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Contributed Papers. AbstractsFate and transport of TNT, RDX, and HMX in streambed sediments: Implications for riverbank filtration Weixi Zheng, Joseph Lichwa, Matteo D’Alessio, Chittaranjan Ray Riverbank filtration (RBF) refers to the process of capturing surface water passing through the river-sediment- aquifer system by using a collection technique such as a well or an infiltration gallery. RBF removes nearly all suspended and a large number of dissolved contaminants from the surface water. Therefore, it can function as an effective pretreatment process in drinking-water production. TNT (2,4,6-trinitrotoluene), RDX (1,3,5-trinitro-1,3,5-triazacyclohexane), and HMX (1,3,5,7-tetranitro- 1,3,5,7-tetrazocane) are three military explosive chemicals that are considered of concern to human health when present in source waters. This study is to evaluate the ability of the filtration media in RBF systems to remove these chemicals. The results from an anoxic batch test showed that all three chemicals will degrade while passing through streambed sediments. The pseudo first-order degradation- rate constants for TNT, RDX, and HMX were measured to be 0.33, 0.055, and 0.033 d1, respectively. Under aerobic conditions only TNT showed significant degradation. Results from a model RBF system showed that the mobility of the three chemical contaminants in streambed sediments was in the order: HMX > RDX > TNT. The results suggest that RBF is capable of removing TNT and RDX but HMX levels may continue to be of concern—especially when collector wells use laterals running directly beneath the stream or riverbed. Reducing the Complexity of Inverse Analysis of Time Domain Reflectometry Waveforms Xiufu Shuai, Ole Wendroth, Caicheng Lu, and Chittaranjan Ray Inverse analysis of time domain refl ectometry (TDR) waveform in the frequency domain is important in measuring complex dielectric permittivity of soils. However, for widely used probes designed as impedance mismatching and nonseparable connection between probe head and coaxial cable, none of the available models can be used for the inverse analysis. The objective of this study was to derive a model which is applicable for this specifi c type of probes. A two-section (probe head and probe rods) model was derived from the full model of Feng et al. (1999) by reducing its complexity on the basis of the matching design of cable tester and coaxial cable. The model was validated by comparison of the measured spectra of properly terminated coaxial cable with the theoretical values, and the accuracy of the model was studied by the comparison of the estimated complex dielectric permittivity of ethanol by the model with those measured by the network analyzer method. This model was applied to a silt loam soil under different levels of water content and electrical conductivity (EC). The results showed that the two-section model was applicable for this specifi c type of probes to measure complex dielectric permittivity at low frequency range. The lowest frequency of 30 MHz was used to estimate soil complex dielectric permittivity. The real parts of the estimated soil dielectric permittivity were close to the apparent dielectric permittivity determined by travel time analysis (TTA). The soil bulk EC calculated from the imaginary parts of the estimated soil dielectric permittivity was close to the measured values. Use of Artificial Neural Networks for Predicting of Groundwater Contamination Sahoo, Goloka Behari, and Chittaranjan Ray. Artificial neural networks are empirical mathematical tools proven to represent complex
relationships of hydrological systems. Neural networks are increasingly being applied in
subsurface modeling where intricate physical processes and lack of detailed field data prevail.
Two types of ANN models: Back propagation neural network (BPNN) and radial basis function neural
network (RBFN) are examined to predict the pesticide contamination of domestic wells. Because
sample collection, analysis, and re-sampling are expensive, a large dataset is not available for
ANN use in this study. This study presents analyzes of raw data for preparation of input subsets
for ANN use. Thus, a clustering technique is used to divide the whole dataset into three subsets:
training, validating, and testing. The sensitivity analysis was carried out by deleting one or
more input variables from the input data set to measure the importance of one variable over the
other in terms of ANN prediction performance. It provides a sense of the effect of each parameter
on pesticide occurrence in a well. The well depth, depth to aquifer material from land surface,
and on-site pesticide storage are found to be important parameters in pesticide occurrence in well.
Flow Forecasting Using Artificial Neural Network and a Distributed Hydrological Model, MIKE SHE
Sahoo, Goloka Behari, and Chittaranjan Ray.
Many drainage basins in Hawaii, especially those on Oahu, are highly urbanized with large areas of impervious surface
that produce nearly 100% runoff. Streamflows change by a factor of 60 in only 15 minutes during flashfloods, because
these streams are short and steep and respond quickly to intense tropical storms. No matter how small is the scale,
many tropical storms on Oahu lead to flash foods and cause life and property damage. Thus, forecasting and analysis
of runoff and streamflow in relation to the size and land-use characteristics of individual drainage basins are
important for flood and land resources management. This study presents flow estimation of a tropical mountainous
stream on Oahu at a 15-minute frequency using a back-propagation neural network (BPNN) and a physically. distributed
model MIKE SHE (DHI, 2003).
It was found that BPNN was able to predict the streamflow with a correlation coefficient (R) greater than 0.99. It was
demonstrated that BPNN was found to be superior to MIKE SHE in terms of predictive performance efficiency: R, mean error,
and root mean square error when all information at the gauging stations: stream stage, rainfall, and evapotranspiration
was available. MIKE SHE produced continuous and consistent results along the streams (gauged and ungauged locations) with
R approximately 0.7. Also, MIKE SHE produced results at multiple sites (i.e. at gauged and ungauged stations) and at
multiple scales (e.g., streamflow, groundwater head, surface water level, and soil moisture content). While BPNN is
not intended as a substitute for a conceptual model, it can be used as a viable alternative to a physically-distributed
model only if streamflows at gauging sites are required. The advantages and limitations of using empirical BPNN and a
distributed physical based model for flow forecasting are discussed
Distribution of Discharge Intensity along Small-Diameter
Collector Well Laterals in a Model Riverbed Filtration Seung-Hyun Kim, Kyu-Hong Ahn, and Chittaranjan Ray
Experiments were performed to evaluate flow and head variations along perforated screens 10–30 mm in diameter using
sand tanks which were connected and a perforated screen extended through these tanks to form a model collector well lateral up to 2.6 m
in length. Hydraulic heads and discharge along the lateral and production rates of the model collector well were measured as the water
level in the well, the lateral length, and diameter, and the hydraulic conductivity of the filter sand were varied. A mathematical model was
developed to predict the axial flow velocity distribution and the discharge intensity variation along the lateral using the head distribution.
Results showed that the production rate increased as the lateral length and diameter and the drawdown at the well increased. However, the
production rate increase was not linearly related to these factors. When larger-diameter laterals were used, the axial flow velocity in the
laterals decreased. This caused the hydraulic heads along the lateral to become more flattened, resulting in a lateral of high efficiency in
terms of water production. This condition is similar to the assumption of the uniform discharge intensity along the lateral that many
researchers have used in the analysis of the horizontal wells. Under the conditions of this study, a critical axial flow velocity was
determined to be 1 m/ s. Hydraulic efficiency decreased drastically when the velocity exceeded 1 m/ s. The roughness coefficient the
Manning’s n value of the lateral varied as a function of factors such as axial velocity and discharge intensity, and it ranged from 0.010
to 0.015.
Microgenetic algorithms and artificial neural networks to assess minimum data requirements for prediction of pesticide concentrations
in shallow groundwater on regional scale.
Sahoo, Goloka Behari, and Chittaranjan Ray.
Artificial neural networks (ANNs) have been extensively used for forecasting
problems involving water quantity and quality. In most cases, the geometry and model
parameters of the ANN are set using a trial-and-error approach to achieve better network
generalization ability, whereby the available data are divided arbitrarily into training,
testing, and validation subsets. It has been shown that using the arbitrary sample selection
method to assign samples into the training subset commonly results in the inclusion of
samples from densely clustered regions and omission of samples from sparsely
represented regions. This paper presents a systematic approach using the self-organizing
map (SOM) clustering technique that identifies which samples and determines how many
samples should be included in each of the three subsets required by ANN for optimum
predictive performance efficiency. In addition, this paper presents the microgenetic
algorithms (mGA) that optimize ANN’s geometry and model parameters in terms of the
correlation coefficient (R). In the sensitivity analysis, mGA model parameters are found to
be least sensitive to the optimum R value, while ANN’s predictive performance is
significantly affected by (1) the poor selection of its geometry and model parameters and
(2) the arbitrary selection of samples for the three subsets of data used. It is demonstrated
that the mGA-ANN model using the SOM technique for data division outperforms the
mGA-ANN model using arbitrary data division. For the training subset, the model using
the SOM technique identifies samples that are representative of the region, requiring only
20% of the total samples, whereas the arbitrary sample selection method requires
50–90%. Because resampling on a regional scale is expensive and time consuming,
substantial cost and time could be saved if resampling could be done only on the 20%
representative drinking water wells.
Determination of trifloxystrobin and its metabolites in the tropical soils
of Hawaii by ASE-LC/MS/MS
Chen, Jingyu, Chittaranjan Ray, and Binh Loo.
Analytical methods for the determination of trifloxystrobin and four of its metabolites were developed in a leaching study conducted
in Hawaii. To duplicate plots at each of five locations representing various agricultural areas in Hawaii, trifloxystrobin was applied at
label rates and allowed to leach under normal rain and irrigation conditions. Soil samples were collected at weekly to monthly intervals
and the residual concentrations of trifloxystrobin and metabolites measured. A quantitative analytical method for their determination in
various soil samples was developed using accelerated solvent extraction (ASE), coupled with liquid chromatography-tandem mass spectrometry.
Extraction solvent with various ratios of methanol to water, addition of EDTANa2 to the extract solvent, and ASE cell temperature were
adjusted to improve recovery. Deuterated (E,E)-trifloxystrobin was chosen as the internal standard of the analytical method. The limit
of quantitation was 2.5 ppb in the soil for trifloxystrobin and its metabolites. Laboratory aerobic degradation studies with the soils
from the five sites were also conducted to measure the same compounds.
Land management impacts on coastal watershed hydrolgy.
Fares, A., and A. I. El-Kadi.
From the Wit Press website:
(http://www.compmech.com/acatalog/9781845640910.html)
Coastal watersheds differ from others by their unique features, including proximity
to the ocean, weather and rainfall patterns, subsurface features, and
land covers. Land use changes and competing needs for valuable water
and land resources are especially more distinctive to such watersheds.
This book covers recent research relevant to coastal watersheds. It
addresses the impact of a stream’s chemical, biological, and sediment
pollutants on the quality of the receiving waters, such as estuaries,
bays, and near-shore waters. The contents of the book can be divided
into three sections; a) overview of hydrological modelling, b) water
quality assessment, and c) watershed management. This book differs from
other hydrology books by dealing with coastal watersheds which are characterized
by their unique features: including weather and rainfall patterns, subsurface
characteristics, and land use and cover. In addition to academia, the
book should be of interest to organizations concerned with watershed
management, such as local and federal governments and environmental
groups. Overall, the book is expected to satisfy a great need toward
understanding and managing critical areas in many parts of the world.
Movement of bromacil in a Hawaii soil under pineapple cultivation - A field
study
Alavi, G., M. Sanda, B. Loo, R. E. Green, and C. Ray.
Recent discovery of low concentrations of bromacil in drinking water prompted the State of Hawaii to examine the leaching behavior of
bromacil in pineapple fields. This study is a follow up to earlier work on bromacil concentrations in soil profiles in a pineapple field
in central Oahu, Hawaii. Soil samples were collected for bromacil analysis at different times prior to and after application from a pineapple
field that was previously surveyed by other research workers. The leaching pattern of bromacil was further investigated at two different
application rates (2.25 and 1.8 kg ha_1). The concentration of bromacil in the topsoil about 100 days after bromacil application
(1.8 kg ha_1) was substantially higher in 2002 compared to 1999. The distribution profiles were generally consistent with the one
presented in the previous study. Residual bromacil was present in the entire sampled zone (3 m deep) about 18 months after the
previous bromacil application. Over a period of 9 months, there was substantial dissipation of bromacil residue present in the
topsoil. The residual concentration of bromacil in the area that received the reduced application rate (1.8 kg ha_1) were lower
than those receiving the current application rate (2.25 kg ha_1) and the depth of penetration of the bromacil front was shallower
at the reduced application rate. Because of the common practice of placing plastic mulch around the base of the pineapple plants
to retain volatile nematicides, the applied bromacil was found to be concentrated in the areas between the plastic mulch, transported
by runoff from the plastic. The study results encourage the use of less than the label led rate of application of bromacil for pineapple
fields.
Estimating hydraulic properties of coastal aquifers using wave setup.
Rotzoll, K., and Aly I. El-Kadi.
Wave setup is the elevated mean water-table at the coast associated with the momentum transfer of wave breaking, which occurs generally over several days. Groundwater
responses to wave setup were observed as far as 5 km inland in central Maui, Hawaii. The analysis showed that at times of energetic swell events wave-driven watertable
overheights dominate low-frequency groundwater fluctuations associated with barometric pressure effects. Matching peak frequencies at 1.7 x 10-6 Hz and 3.7 x 10-6 Hz
were identified in setup and observed head using spectral decomposition. Similar to tides, the setup propagation through the aquifer shows exponentially decreasing
amplitudes and linearly increasing time lags. Due to the longer periods of setup oscillations, the signal propagates deeper into the aquifer (~10 km in central Maui)
than diurnal tides (5 km) and can therefore provide information on greater length scales. Hydraulic diffusivity was estimated based on the setup propagation. An
effective diffusivity of 2.3 x 107 m2/d is consistent with aquifer parameters based on aquifer tests and tides. A one-dimensional numerical model supports the results of
the analytical solution and strengthens the suitability to estimate hydraulic parameters from setup propagation. The methodology is expected to be beneficial to
high-permeability coastal environments, such as on volcanic islands and atolls.
Use of dissolved helium as an environmental water tracer.
Ritcher, F., and A. I. El-Kadi.
Abstract: This study deals with the development, calibration, and testing of an
automated technology for using helium as a water tracer in continuous real-time
monitoring. The instrument combines a gas extraction system and a helium mass
spectrometer. The technology was tested in laboratory pipe, open-water, and porousmedia
experiments, and the results were used to test helium breakthrough curves against
those for salinity expressed by electrical conductivity. The instrument promptly responds
to concentration changes. In general, accurate results were obtained for first arrival times
and peaks of solutes, as well as for the dispersive characteristics of the breakthrough
curves. The accuracy of the elution curves needs some improvement due to limitations of
the helium extraction system. In addition, the developed method is sensitive to the water
flow rate and nitrogen pressure used in extracting helium from the solution. These issues
can be addressed through calibration. Potential improvements are possible through the
use of more precise helium concentration quantification equipment and through
enhancement of the extraction method. The success of the methodology makes helium an
attractive tracer for use near drinking water sources, in environmentally sensitive areas
such as wetlands and fish farms, and near recreational or other areas where esthetics are a
concern.
Analysis of an unconfined aquifer subject to asynchronous dual-tide propagation
Rotzoll, Kolja, Aly I. El-Kadi, and Stephen B. Gingerich.
Most published solutions for aquifer responses to ocean tides
focus on the one-sided attenuation of the signal as it propagates
inland. However, island aquifers experience periodic forcing from
the entire coast, which can lead to integrated effects of different
tidal signals, especially on narrow high-permeability islands. In
general, studies disregard a potential time lag as the tidal wave
sweeps around the island. We present a one-dimensional analytical
solution to the ground-water flow equation subject to asynchronous
and asymmetric oscillating head conditions on opposite boundaries
and test it on data from an unconfined volcanic aquifer in Maui.
The solution considers sediment-damping effects at the coastline.
The response of Maui aquifers indicate that water-table elevations
near the center of the aquifer are influenced by a combination of
tides from opposite coasts. A better match between the observed
ground-water head and the theoretical response can be obtained with
the proposed dual-tide solution than with single-sided solutions.
Hydraulic diffusivity was estimated to be 2.3 x 107 m2/d. This
translates into a hydraulic conductivity of 500 m/d, assuming a
specific yield of 0.04 and an aquifer thickness of 1.8 km. A
numerical experiment confirmed the hydraulic diffusivity value and
showed that the y-intercepts of the modal attenuation and phase
differences estimated by regression can approximate damping factors
caused by low-permeability units at the boundary.
Estimating hydraulic conductivity from specific capacity for Hawaii aquifers
Aly I. El-Kadi.
Site-specific relationships between specific capacity
and hydraulic parameters (transmissivity and
hydraulic conductivity) were investigated for volcanic
rocks in Maui, Hawaii, USA. Details about well construction
were commonly ignored in previous studies. To
improve on such efforts, specific-capacity values were
normalized by the open interval of the well. Correcting
specific capacity for turbulent head losses using stepdrawdown
tests and including aquifer penetration length
improved the correlation between specific capacity and
hydraulic conductivity and reduced uncertainty in the
prediction of hydraulic parameters. The relationships
provide estimates of aquifer parameters with correlation
coefficients between 0.81 and 0.99. The relationships for
Maui can probably be extended to other Hawaii islands,
given the similarity of aquifer formations and a reasonable
fit to step-drawdown data from Oahu. Hydraulic conductivity
was estimated from 1,257 specific-capacity values in
the Hawaii’s well database. Hydraulic-conductivity estimates
for dike-free volcanic rocks are consistent on
different islands. For all islands, the estimates range from
3 to 8,200 m/d, with a geometric-mean and median value
of 272 and 291 m/d, respectively. A geostatistical approach
was applied to Maui and Oahu to generate island-wide
hydraulic-conductivity maps to facilitate groundwater management
efforts. Optimization of artificial neural networks using genetic algorithms
Sahoo, Goloka B., and Chittaranjan Ray.
Effect of recycled water on transport of estrone and 178 estradiol in a
tropical soil
Mohanty, Sanjay K., and Chittaranjan Ray.
The nature and value of ecosystem services: An overview highlighting hydrologic services.
Brauman, Kate A., Gretchen C. Daily, T. Ka'eo Duarte, and Harold A. Mooney.
A screening tool for vulnerability assessment of pesticide leaching to groundwater for the islands of Hawaii, USA.
Stenemo, Fredrik, Chittaranjan Ray, Russell Yost, and Steven Matsuda.
An evaluation of the mobility of pathogen indicators, Escherichia coli and
bacteriophage MS-2, in a highly weathered tropical soil under saturated conditions
Wong, Tiow-Ping, Muruleedhara Byappanahalli, Bunnie Yoneyama, and Chittaranjan
Ray.
Evaluation of dual-permeability models for chemical leaching assessment
to assist pesticide regulation in Hawaii
Alavi, G., J. Dusek, R. E. Green, and C. Ray.
Groundwater is the primary source of drinking water for all the islands of Hawaii. Past agricultural practices have led to the contamination of
groundwater in certain locations. As a result, the state of Hawaii emphasizes the prevention of contamination of groundwater from the leaching of pesticides.
Hawaii currently uses a simple (Tier I) screening assessment model to evaluate the leaching potential of pesticides. This model is only capable of indicating if a
chemical is likely to leach; it can estimate neither the concentration profile in soil nor the concentration in leachate water. The USEPA is seeking partnership
with the state of Hawaii for examining the feasibility of using Tier II models in Hawaii conditions for pesticide registration. Two pesticide leaching models,
MACRO 4.3 and S1D DUAL, were tested using leaching data for five pesticides from a field site on the island of Oahu. Despite deficiencies, it is one of the best
data sets currently available for tropical soils. Both MACRO 4.3 and S1D DUAL models explicitly include preferential flow components but use different concepts in
model formulations. The performances of the two models were generally similar. The results show that preferential flow had a minor role in transporting the chemicals
compared with micropore flow because of the high saturated conductivity of micropores (matrix). We conclude that a process-based model will contribute substantially
to the evaluation of chemical leaching risk and complement the Tier I model that currently is used for pesticide registration in Hawaii.
Evaluation of enterococcal surface protein genes as markers of sewage contamination
in tropical recreational waters
Betancourt, W. Q., and R. S. Fujioka.
A molecular monitoring strategy was developed to detect prevalence of two enterococcal
surface protein genes (esp-1 gene and esp-2 gene) in isolates of enterococci
from recreational waters in Hawaii as evidence of human sewage contamination.
The sensitivity and specificity of the methods were evaluated in selected environmental
samples including human sewage, ocean water samples near a sewage outfall, shoreline
coastal beach waters, ambient soil samples, and ambient streams not known to
be contaminated with sewage. The results of this study show that the esp-1 and
esp-2 genes are highly associated with enterococci from sewage sources as compared
to non-point sources. Therefore these esp genes show promise as good indicators
of sewage contamination. However, more sensitivity and specificity of esp genes
are needed. Moreover, a more specific enumeration method for E. faecium
and E. faecalis is needed so that subsequent test for the esp genes will
be reliable and feasible. Monitoring strategy using FRNA coliphages and Clostridium perfringens
to detect sewage contamination of recreational waters by subsurface cesspool
discharges and surface sewage spill
Vithanage, G., G. Ueunten, and R. Fujioka.
Conclusions on the microbial quality of environmental waters in the state of
Hawaii are based primarily on data collected on the most urbanized and populated
island of Oahu and applied to the other six islands in the state. The objective
of this study was to assess the reliability of monitoring environmental waters
on the Hawaiian Island of Kauai for FIB or faecal indicator bacteria (faecal
coliforms, enterococci) as well as for alternative faecal indicators (C.
perfringens, F+ coliphages). The island of Kauai differs from Oahu in being
less urbanized, having higher rainfall and where sewage is primarily treated
by on-site cesspools. The monitoring data from this study confirmed data obtained
on Oahu that under ambient conditions, faecal coliforms and enterococci are
naturally present in high concentrations in soil, that soil rather than sewage
is the primary source for the high concentrations in all streams and therefore
FIB are unreliable indicators of sewage contamination. This study resulted in
new findings that monitoring for F+ coliphages but not C. perfringens
can detect stream contamination by subsurface cesspool wastes. Moreover, by
identifying and genotyping FRNA coliphages, additional evidence was obtained
to show that cesspool wastes are contaminating streams on Kauai. Distribution of discharge intensity along collector well laterals in a model
of riverbed filtration
Kim, Seung-Hyun, Kyu-Hong Ahn, and Chittaranjan Ray.
ABSTRACT
Esssential oils of selected Hawaiian plants and associated litters
Chen, Jingyu, Joseph Lichwa, and Chittaranjan Ray.
The chemical composition of the essential oils from the leaves of Araucaria
heterophylla (also known as Norfolk Island pine), Casuarina cunninghamian,
Eucalyptus citriodora, Psidium cattlenium , var. lucidum (also known
as strawberry guava), and litters of the first two species were studied using
two gas chromatography techniques, one equipped with a mass spectrometer detector
(GC/MS) and the other with a flame ionization detector (GC/FID). Six volatile
compounds were identified in the leaf oil of A. heterophylla. A substantial
increase in the amount of a-pinene, a-terpinene
and a decrease in the amount of (b-caryophyllene
was noticed in the litter oil of A. heterophylla. Three volatile compounds
were identified in C. cunninghamian. Another monoterpene, a-terpinene,
was observed in the litter oil of C. cunninghamian.. Eleven compounds
were identified in the leaf oil of P. cattlenium, of which b-caryophyllene
(59.0%), a-pinene (13.2%) and myrcene (11.3%) were
the major components. Thirteen volatile oil compounds were identified in the
E. citriodora leaf oil, of which citronellal (42.8%), citronellol (17.9%)
and a-terpinene (11.2%) were the major components.
A mini-review of modeling studies on membrane bioreactor (MBR) treatment
for municipal wastewaters
Ng, Aileen N.L. & Albert S. Kim Estimating hydraulic proerties of volcanic aquifers using constant-rate and variable-rate aquifer tests Rotzoll, Kolja, Aly I. El-Kadi, and Stephen B. Gingerich In recent years the ground-water demand of the population of the island of Maui, Hawaii, has significantly increased. To ensure prudent management of the ground-water resources, an improved understanding of ground-water flow systems is needed. At present, large-scale estimations of aquifer properties are lacking for Maui. Seven analytical methods using constant-rate and variable-rate withdrawals for single wells provide an estimate of hydraulic conductivity and transmissivity for 103 wells in central Maui. Methods based on constantrate tests, although not widely used on Maui, offer reasonable estimates. Step-drawdown tests, which are more abundantly used than other tests, provide similar estimates as constant-rate tests. A numerical model validates the suitability of analytical solutions for step-drawdown tests and additionally provides an estimate of storage parameters. The results show that hydraulic conductivity is log-normally distributed and that for dike-free volcanic rocks it ranges over several orders of magnitude from 1 to 2,500 m/ d. The arithmetic mean, geometric mean, and median values of hydraulic conductivity are respectively 520, 280, and 370 m/ d for basalt and 80, 50, and 30 m/d for sediment. A geostatistical approach using ordinary kriging yields a prediction of hydraulic conductivity on a larger scale. Overall, the results are in agreement with values published for other Hawaiian islands.Analytical groundwater modeling for estimating sustainable yield of lao Aquifer, Maui, Hawaii. Liu, C. C. K., and X. Li. 2007. Since 1980, several numerical models of groundwater flow and salinity transport have been developed for Hawaii basal aquifers. At this time, however, they are too complicated as viable management tools because adequate calibration and verification of these models require extensive field data which are not currently available. In our study, a simple robust analytical model called RAM2 was developed by taking Hawaii basal aquifers as a completely stirred tank reactor. RAM2 consists of (a) a flow submodel and (b) a salt transport submodel which simulates the evolution of the transition zone in a basal freshwater lens. The mathematical structure of RAM2 is simple, such that it can be solved analytically and can be readily calibrated using available field data. Its usefulness as a management tool was demonstrated by applying it in an evaluation of the sustainable yield of the Iao aquifer on Maui, Hawaii. Modeling streamflows and flood delineation of the 2004 flood disaster, Manoa, Oahu, Hawaii. El-Kadi, Aly I., and Eric Yamashita. In October 2004 a flood caused extensive damage to the University of Hawai‘i (UH) campus and neighboring residential areas in Mãnoa Valley, O‘ahu, Hawai‘i. This modeling study was aimed at streamflow evaluation and flood delineation for the area impacted by the flood. The study concluded that the HEC-1 model of the U.S. Army Corps of Engineers is suitable for simulating storm runoff response for the study area, considering the nature of small Hawai‘i watersheds, which generate hydrographs with steep rising and falling limbs. The curve-number method of the U.S. Soil Conservation Service is also suitable because it predicts reasonably well the main features of streamflow hydrographs, including runoff duration and time of peaks. To improve on accuracy, however, there is a need for better characterization of spatial rainfall distribution through measurements. A flood delineation model, which treats the flood as a hypothetical dam break, was used to predict the floodwater pathway, flood zone extent, maximum flood depth, and the time to reach that depth. The model predicted an upper value for storm total flow volume that would not cause flooding on the UH campus. Although not fully validated, the developed models can guide data-collection and decision-making processes. For example, the models demonstrated that it is possible to mitigate the flood through streamflow diversion and stream dredging, realignment, and lining. For efficient management, we recommend defining a new subwatershed of the Ala Wai basin (to be called the West Mãnoa Watershed) that contains the university campus. Use of dissolved helium as an environmental open-water tracer. Richter, Florian, Robert B. Whittier, and Aly I. El-Kadi. 2006.
A screening tool for vulnerability assessment of pesticide leaching to groundwater for the islands of Hawaii, USA. Stenemo, Fredrik, Chittaranjan Ray, Russell Yost, and Steven Matsuda. This paper describes an updated version of a screening tool for groundwater vulnerability assessment to evaluate pesticide leaching to groundwater, based
on a revised version of the attenuation factor. The tool has been implemented in a geographical information system (GIS) covering the major islands of the
state of Hawaii, USA. The Hawaii Department of Agriculture currently uses the tool in their pesticide evaluation process as a first-tier screening tool.
The basic soil properties and pesticide properties necessary to compute the index, and estimates of their uncertainty, are included in the GIS. Uncertainties
in soil and pesticide properties are accounted for using first-order uncertainty analysis. Classifications of pesticides as likely, uncertain or unlikely to
leach are made on the basis of the uncertainty and a comparison of the revised attenuation factor with values and uncertainties of two reference chemicals.
The reference chemicals represent what are considered to be a leachable and a non-leachable pesticide under Hawaii conditions. It is concluded that the tool
is suitable for screening new and already used pesticides for the islands of Hawaii. However, the tool is associated with uncertainties that are not accounted
for, so a conservative approach with respect to interpretation of the results and selection of pesticide parameters used in the tool is recommended. Analytical groundwater modeling for estimating sustainable yield of a basal freshwater lens. Liu, Clark C. K., John F. Mink, and John Dai.
Restoration and protection plan for the Nawiliwili Watershed, Kauai, Hawaii, USA. El-Kadi, Aly I., Monica Mira, James E. T. Moncur, and Roger S. Fujioka.
Cake resistance of aggregates formed in the diffusion-limited-cluster-aggregation (DLCA) regime. Kim, Albert S., and Rong Yuan. The ideal aggregate characterized by the quadratically increasing permeability k(r) = k2r2 is investigated to estimate the specific cake resistance (i.e., inverse permeability) of a cake layer composed of deposited aggregates formed in the diffusion-limited-cluster-aggregation (DLCA) regime. Happel's cell model is employed in this study by embedding the ideal aggregate in the center of a spherical cell of tangential stress-free surface. The specific resistance is analytically calculated as a function of the occupancy fraction and then compared to those of conventional cake layers of equal-sized spherical colloids and uniformly porous spheres. The DCLA-aggregate cake layer provides significantly less specific resistance and therefore shows the remarkable potential of aggregate-enhanced membrane filtration (AEMF) as a new protocol for colloidal filtration. The settling velocity of a swarm of the ideal aggregates is investigated as a by-product and experimental verification of this theory. Parameter sensitivity of a hydrocarbon biodegradation model under uncertainty of permeability. El-Kadi, Aly I. The effects of permeability variability on uncertainty of the results of a hydrocarbon biodegradation model are addressed. The model includes saturated and unsaturated flow, multi-species transport, heat transport, and bacterial-growth processes. A stochastic approach was used in the uncertainty analysis. Sensitivity analyses were conducted, taking into consideration the effects of heterogeneity. The Monte Carlo method was used, with permeability as the input stochastic variable. Results showed that uncertainty increases with time. This can lead to difficulties regarding cleanup decision making such as predicting the timeframe to reach an aquifer cleanup goal. It was not possible to replace the heterogeneous system with a homogeneous one through the use of effective parameters that preserve an equivalent behavior of the two systems. Effective permeability is space and time dependent and also depends on values of bioactivity parameters. The study also emphasized the importance of accurately measuring certain bacterial parameters, namely, maximum substrate uptake rate for degradation and cell yield coefficient. Uncertainties regarding nutrient and oxygen uptake and saturation parameters were less important for the current application. Assessment of submarine groundwater discharge by handheld aerial infrared imagery: case study of Kaloko Fishpond and Bay, Hawaii Duarte, T. Ka'eo , Harold F. Hermond, Donald Frankel, and Sheila Frankel Handheld aerial infrared imagery was used to infer submarine groundwater discharge (SGD) to a Hawaiian fishpond and adjacent bay at Kaloko, Hawai'i, using heat as a tracer for the relatively cooler groundwater. Use of a handheld infrared camera aboard readily available, unmodified aircraft is a convenient and less expensive alternative to use of a camera mounted in the belly of a customized aircraft, although it favors taking images with an oblique view instead of the preferable nadir view. Pond-wide patterns of SGD were readily apparent in oblique images and were typically more apparent in infrared imagery than in ground truth data, due to the formation of thin (order of cm) surface strata of groundwater which could easily fail to be observed with conventional temperature probes. Absolute temperature measurement is affected by the variation of surface emissivity and reflectivity with angle of camera view; corrections based on use of Fresnel's equation were of the order of several degrees centigrade at convenient oblique aerial viewing angles. Other factors that may affect apparent water temperature include sky temperature and camera error. Surface waves may also account for variations in average surface emissivity and reflectance that were not accounted for by the aforementioned corrections. Under suitable conditions, handheld aerial infrared imagery revealed spatial patterns of groundwater inflow, detected differences in water temperature at the meter scale, and measured absolute water temperature with accuracy on the order of 2 to 3 °C.The History of Groundwater Management and Research in Hawaii El Kadi, Aly L., and James E.T. Moncur This paper reviews groundwater research studies with emphasis on modeling as a tool for management of Hawaii's resources. Hawaii depends to a great extent on groundwater resources, and concern over availability of potable water has guided research regarding both water quantity and quality. Research is mainly aimed at understanding Hawaii hydrogeology, identifying aquifer parameters and modeling needs, and applying models in the management of resources. Use of models has advanced over the past ten years toward routine aquifer management, yet there is a great need to better characterize aquifer spatial data. Variability of hydrogeological conditions is a major hurdle for successful application of models. This paper also addresses legal, institutional, and economic issues pertinent to Hawaii's pressing problems regarding water allocation. Areas of critical research needs are also identified.EPS membrane biofouling in membrane filtration: An analytic modeling study Kim, Albert S., Huaiqun Chen, Rong Yuan Biofouling is theoretically investigated by modeling solute transport within a biofilm, defined in this study as a swarm of solid biocolloids surounded by liquid-like exopolymeric substances (EPS). A mathematical approach is employed to map the biofilm to an equivalent, simple speherical cell using a self-consistent method. It is found that the physical presence of EPS' and their reaction with solute ions reduce the mass transfer coefficient, which significantly contributes to permate flux decline in reverse osmosis and nanofiltration menmbrane proceseses.Hydraulic permeability of polydispersed cake layers: an analytic approach Kim, Albert S., Aileen N.L. Ng An analytic method is introduced to calculate hydraulic permeability of porous media composed ofpolydispersed spheres with log-normal and normal (Gaussian) distributions of particle sizes. From the comparison of the permeability for the two particle-size distributions, it was observed that a medium with normally distributed particle sizes consistently has a lower permeability than a medium with log-normally distributed particle sizes. This phenomenon is due to the larger number of smaller particles in the normal distribution, which results in greater cake resistance. The specific resistance of the cake layer is computed by taking the inverse of the permeability.A postaudit study of DBCP and EDB contamination in the Pearl Harbor aquifer Rungvetvuthivitaya, Mongkolaya, Chittaranjan Ray, Richard E. Green A simulation of the transport of dibromochloropropane (DBCP) and ethylene dibromide (EDB) in the vadose zone and ground water was conducted in the Mililani area of Central Oahu, Hawaii to revisit the groundwater contamination predictions made by researchers at the University of Hawaii in 1988 for selected wells of the Honolulu Board of Water Supply. Examination of sampled DBCP results in these wells indicated a large discrepancy between the observed and predicted concentrations in 1988. Therefore, a post-audit study was initiated in the same area to assist in better defining projected concentrations of contaminants in well waters in the future. With the new data, different modeling approaches were undertaken for simulating flow and contaminant transport in both the vadose and saturated zones. The new simulations indicate travel times of 14 to 32 years for contaminants to reach the water table, depending on the location. The approximate recovery time of wells in the study area is expected to occur after the year 2016 for DBCP. The predicted concentration of EDB in the wells is less than the current detection limit. Variabilities in model predictions due to parameter uncertainties and model limitations are also considered. While the predicted concentrations from the present simulations match sampled data better than the concentrations from earlier modeling efforts, still a number of uncertainties remain.Determination of hormones and non-ionic surfactant degradation products in small-volume aqueous samples from soil columns using LC-ESI-MS-MS and GC-MS Chen, J., J. Lichwa, M. Snehota, S. Mohanty, C. Ray The leaching of two estrogens, 17 beta-estradiol and estrone, and two degradation products of non-ionic surfactants, octylphenol and nonylphenol, through a soil column were studied to estimate their transport behavior. Different concentration methods (lyophilization, solid phase extraction, and liquid-liquid extraction) were evaluated for analyzing these compounds in small effluent fractions (30-50 mL) collected. Liquid chromatography-mass spectrometry (LC-MS-MS) and gas chromatography-mass spectrometry (GC-MS) were employed for quantitative analysis of these compounds. After comparison, the lyophilization LC-MS-MS method was found to be best suited for the analysis of the two estrogen hormones and the liquid-liquid extraction GC-MS method best for the analysis of the two phenols in small samples in the soil column study. Because of their high sorption capacity, these compounds were mostly sorbed in the upper part of the soil column and were difficult to detect in column effluent.Predicting flux decline in crossflow membranes using artificial neural networks and genetic algorithms Sahoo, Goloka Behari, Chittaranjan Ray The geometry and internal parameters of artificial neural networks (ANNs) have significant effects on the prediction performance efficiency of the network. The optimal ANN geometry is problem-dependent. Although some guidance is available in the literature for the choice of geometry and internal parameters, most networks are calibrated using the trial-and-error approach. This paper presents the use of genetic algorithms (GAs) to search the optimal geometry and values of internal parameter of a multilayer feedforward back-propagation neural network (BPNN) and a radial basis function network (RBFN). The prediction performance efficiency of the GA-ANN combination is examined using an already published experimental dataset of crossflow membrane filtration. The data includes the permeate flux decline under various operating conditions (e.g. transmembrane pressure and filtration time) with different physicochemical properties of feed water (e.g. different combinations of three particle diameters, three pH values and four ionic strengths). It is illustrated that the GA-optimized ANN predicts the permeate flux decline more accurately than a network in which the ANN calibration is done using a trial-and-error approach. It is shown that scaling the training data to the range of 0-1 helps the modeler find the solution range of an RBFN for GA.A wind-driven reverse osmosis system for aquaculture wastewater reuse and nutrient recovery Liu, C.C.K., W. Xia, J.W. Park A wind-driven reverse osmosis system for aquaculture wastewater treatment, developed at the University of Hawaii at Manoa, was tested at the experimental facilities on Coconut Island, Oahu, Hawaii. With this technology, a fish tank becomes a closed aquaculture production system with zero waste discharge. The permeate (freshwater) from the system can be used as the freshwater supply for fish culture, while the brine (concentrated wastewater) can be further processed into fish feed by a duckweed-covered reactor.Use of neural network to predict flash flood and attendant water qualities of a mountainous stream on Oahu, Hawaii Sahoo, G.B., C. Ray, E.H. De Carlo Frequent flash floods of Hawaii streams pose continuous threats to the coastal environment because the streams respond rapidly to high runoff and huge transport quantities of sediments, to which are sorbed nutrients, heavy metals, and persistent hydrophobic organic compounds. High-frequency stream flow and water quality estimation are essential to correctly assess water quality variations and pollutant loads during flash floods, because stream flow and turbidity in Hawaii can change by a factor of 60 and 30, respectively, in 15 min. This study shows the application of artificial neural networks (ANNs) to assess flash floods and their attendant water quality parameters using measured data of a Hawaii stream. The paper illustrates that ANNs predict stream flow with a correlation coefficient (R) greater than 0.99 and turbidity and specific conductance with R-values greater than 0.80. Although the R-values for the estimation of dissolved oxygen, pH, and water temperature were somewhat low, most of the estimated stream water quality values (turbidity, specific conductance, dissolved oxygen, pH, and water temperature) were within the limits of ±30% deviations of the 1:1 line. The R-value for the estimation of stream water qualities could have been significantly improved if high resolution (at 15 min or lower measurement frequency), noise-free, and continuous data were available for a longer period of time. The paper demonstrates that the upstream water quality parameters depend on weather forces and land use of the watershed and the downstream water quality parameters additionally influenced by oceanic tides. Stream stage is found to be an important input parameter for stream flow prediction using ANN; however, the predictive performance of ANN for the estimation of stream flow is improved if weather data, rainfall, and evapotranspiration are included in the input data set.Calibration and validation of a physically distributed hydrological model, MIKE SHE, to predict streamflow at high frequency in a flashy mountainous Hawaii stream G. B. Sahoo, C. Ray, E. H. De Carlo Hawaii streams are short and steep, often producing dangerous flash floods as a result of rainfall events that can be short but intense. The streamflow can change by a factor of 60 in only 15 min. Using streamflow data collected at 15-min intervals, the physically distributed modeling system, MIKE SHE, is applied to the Manoa-Palolo stream system on the island of Oahu, Hawaii, to study the watershed response to storm events. Because of the unavailability of detailed spatially distributed data, a single-valued hydraulic conductivity for the saturated zone is used as the representative of the entire watershed. It is shown that a well-calibrated MIKE SHE with the single-valued hydraulic conductivity is able to produce consistent results with correlation coefficients greater than 0.7. The rainfall distribution along the watershed is the driving factor for the estimation of streamflow. The reciprocal of Manning's roughness coefficient (M) for the watershed and the hydraulic conductivities (vertical and horizontal) of the saturated zone had the most pronounced effects in determining the shape of flood peaks. The peak streamflow is reduced by nearly 1 mp3/s for an M value that was changed from 60 to 10. For the upper part of the watershed, which is located in the rainiest and steepest mountainous area, the horizontal hydraulic conductivity value of the saturated zone is insensitive, while the horizontal and vertical hydraulic conductivity values of the saturated zone are sensitive to predict streamflow for the entire watershed. Drainage depth, an average position of phreatic surface above which the water table in one grid starts to drain to the nearest grid or stream, is less sensitive, while drainage time constant, the time required to discharge the drainage water to the nearest grid or stream, is more sensitive for the estimation of base flow. Because calibration for a large basin at small time steps (e.g., every 15 min) takes a long time to complete a year of simulation, splitting the entire watershed into subwatersheds during calibration was useful in examining the effects of key parameters on streamflow estimation before calibrating the parameters for the entire watershed.Diffusive tortuosity factor of solid and soft cake layers: A random walk simulation approach Kim, Albert S., Huaiqun Chen Diffusive tortuosity factor of solid (colloidal) and soft (biofilm) cake layers formed during membrane filtration is investigated using the random walk simulation of solute tracers. Four different structures are investigated as possible candidate structures of the cake layers: simple cubic (SC), body-centered cubic (BCC), face-centered cubic (FCC), and random colloidal cake (RCC) structures. Low porosity of the deformable, compressible soft cake is mimicked by allowing overlaps among the adjacent particles and taking into account only the void spaces. When the volume fraction of each structure is less than its own maximum packing ratio of mono-dispersed solid spheres, Maxwell's theoretical prediction of the diffusive tortuosity factor is accurately superimposed on the simulation results, showing structural indifference of the tortuosity factor. However, when the soft cake is compressed so that the volume fraction becomes greater than the maximum packing ratio, the diffusive tortuosity factor surpasses Maxwell's theory and tends to diverge as the porosity reaches zero. The deviation of simulation results from the theory starts near the maximum packing ratio of each structure, and SC and FCC structures show higher diffusive tortuosity factors in comparison to the BCC structure. Most important, the RCC layer with a realistic irregular configuration has the highest diffusive tortuosity factor over almost the entire range of volume fraction. This implies that the solute diffusion within the soft cake layer of a random irregular structure is most hindered so that the concentration polarization and osmotic pressure of the solutes are accordingly enhanced on the membrane surface.Unconfined Groundwater El Kadi, Aly An article in "Water Encyclopedia", ed. Jay Lehr, Jack Keeley, and Janet Lehr, 662-667. John Wiley & Sons, Available online at www.mrw.interscience.wiley.com/eowWater Management and Water Reuse Moreland, Victor, Roger Fujioka Water management is a process for determining a proper blend between demand management and supply augmentation with options that provide a long - term, reliable water supply for all beneficial uses ( best water source use) at a reasonable cost (financial resources best use) and with the highest possible benefits to the water users, economic development, environmental quality, and other perceived society needs. Drinking water requires a multi - barrier approach to providing proper quality water to protect the public health of our world's population. The first barrier starts with protecting water sources, both surface waters and groundwaters. This source water protection and the other barriers will be discussed in the text of this paper. Drinking water quality is not required for all uses and source waters should be paired appropriately with needed quality water for its intended use (irrigation does not require potable water). Even treated wastewaters have beneficial uses for other than drinking purposes as long as appropriate laws, regulations, and government sponsored monitoring and enforcement can provide acceptable public health risk. Monte Carlo simulation of colloidal membrane filtration: Principal issues for modeling Jim C. Chen, Albert S. Kim The principal issues involved in developing a Monte Carlo simulation model of colloidal membrane filtration are investigated in this study. An important object for modeling is the physical dynamics responsible for causing particle deposition and accumulation when encountering an open system with continuous outflow. A periodic boundary condition offers a solution to the problem by recirculating continuous flow back through the system. Scaling to full physical dimensions will allow for release of the model from flawed assumptions such as constant cake layer volume fraction and thickness throughout the system. Furthermore, rigorous modeling on a precise scale extends the model to account for random particle collisions with acute accuracy. A major finding of this study proves that forces within the colloidal filtration system are summed and transferred cumulatively through the inter-particle interactions. The force summation and transfer phenomenon only realizes its true value when the model is scaled to full dimensions. The overall strategy for model development, therefore, entails three stages: first, rigorous modeling on a microscopic scale; next, comprehensive inclusion of relevant physical dynamics; and finally, scaling to full physical dimensions. A new marine species of Tubificoides (Annelida: Oligochaeta: Tubificidae) from Hawaii, U.S.A. Christer Erseus, Olav Giere, Jennifer Dreyer, and Julie H. Bailey-Brock Tubificoides calvescentis is described from subtidal sediments near a sewage outfall at Sand Island, off Honolulu, Oahu, Hawaii. It is characterized by hair chaetae being restricted to preclitellar segments, small atria and sperma-thecae, and smooth, cylindrical, cuticular penis sheaths. Tubificoides bakeri Brink-hurst, 1985, known from the West coast of North America, appears to be closely related to the new species; its male genitalia are virtually identical to those of T. calvescentis. However, T. bakeri does not possess distinct cuticular papillae, which are evident in T. calvescentis, and it has more numerous chaetae and more slender spermatozeugmata than those of the new species. The paper also provides a nomenclaturally updated list of all marine oligochaetes reported from Hawaii.Bacteroides Spp. as reliable marker of sewage contamination in Hawaii's environmental waters using molecular techniques Betancourt, W.Q., and R.S. Fujioka No AbstractPrediction of permeate flux decline in crossflow membrane filtration of colloidal suspension: A radial basis funcion neural network approach Chen, Huaiqu, and Albert S. Kim No AbstractUse of artificial neural networks to evaluate the effetiveness of riverbank filtration Sahoo, Goloka, B., Chittaranjan Ray, et al. Riverbank filtration (RBF) is a low-cost water treatment technology in which surface water contaminants are removed or degraded as the infiltrating water moves from the river/lake to the pumping wells. The removal or degradation of contaminants is a combination of physicochemical and biological processes. This paper illustrates the development and application of three types of artificial neural networks (ANNs) to estimate the effectiveness of two RBF facilities in the US. The feed-forward back-propagation network (BPN) and radial basis function network (RBFN) model prediction results produced excellent agreement with measured data at a correlation coefficient above 0.99 for filtrate water quality parameters, including temperature as well as turbidity, heterotrophic bacteria, and coliform removal. In comparison, the fuzzy inference system network (FISN) predicted only temperature and bacteria removal with reasonable accuracy. It is shown that the predictive performances of the ANNs depend on the model structure and model inputs. Monte Carlo simulation of colloidal membrane filtration: model development with application to characterization of colloid phase transition. Chen, Jim C., Menachem Elimelech, Albert S. Kim This study investigates phase transition from a fluid-like polarization layer to a solid cake layer of particle deposits during membrane filtration of interacting colloidal particles. A Monte Carlo simulation model of dead-end filtration is used under the influences of hydrodynamic bias from the permeation flux as well as inter-particle interactions. The model effectively demonstrates the roles of the hydrodynamic drag force and inter-particle potential in governing the volume fraction of the particle deposit. The cake layer volume fraction is shown to be sensitive to the combination of particle surface (zeta) potential, solution ionic strength, particle size, and applied transmembrane pressure. Further application of the model leads to a holistic characterization of the phase transition phenomenon. The onset of phase transition is characterized with flexibility and adaptability with concern for both physico-chemical standards, such as volume fraction and inter-particle separation distance, as well as pragmatic considerations, such as the desire to operate the system below the critical flux and avoidance of irreversible cake formation. Simple analytical groundwater modeling for sustainable yield estimation Clark C.K. Liu, John F. Mink, and John Dai Over the last twenty years, numerous modeling efforts were made to simulate the flow and salt transport processes of the Pearl Harbor aquifer, a basal freshwater lens. These modeling exercises enhanced our understanding of the aquifer. However, most of these models are too complicated, such that adequate calibration and verification require extensive field data which are not currently available. A simple robust analytical model (RAM) developed by John Mink in 1980 has been used to estimate the sustainable yield of Pearl Harbor aquifer and many other basal aquifers in the state of Hawaii. Modification of RAM is made in this study by including salt advection-dispersion processes. The modified model consists of two sub-models: (a) a flow sub-model, in the form of the original RAM, and (b) a salt transport sub-model, which simulates the evolution of the transition zone in a basal freshwater lens. The mathematical structure of the modified model remains simple such that it can be solved analytically and can be readily calibrated based on available field data of hydraulic head variations and salinity profiles. Its usefulness as a viable management tool was demonstrated by applying it hi an evaluation of the sustainable yield of the Pearl Harbor aquifer. KEY TERMS: groundwater; basal aquifer; sustainable yield.Calibrating steady-state river water quality models with field data Liu, Clark C.K. In this study, a formula that separates the time-varying effect from observed dissolved oxygen (DO) data was derived. This formula calculates the steady-state DO profile along a biologically active river by "filtering" out the time-varying effect from field-measured diurnal DO curves along the river. As a result, both the model and the data used for its calibration are completely in a steady-state mode, so that model parameters which represent relevant transport and transformation processes can be determined properly. Progoniada oahuensis, a new species from Oahu, Hawaii (Annelida: Polychaeta: Goniadidae) Brendan M. Barrett and Julie H. Bailey-Brock A new species of Progoniada is described. This is the third species in the genus and the first known from the Hawaiian Islands. It differs from the two previously known species in having two compound falcigerous chaetae, jaws with 5 teeth in the ventral arc, proboscis papillae of two types, and compound falcigers with blades less than half the length of the spiniger blades, Distribution in Hawaiian waters is from 34 and 70 meters at sewage outfalls and at disposal dump sites off Oahu at 397 and 502 meter depths. Hydrodynamics of an ideal aggregate with quadratically increasing permeability Liu, Clark C.K. In this study, we consider the ideal aggregate with quadratically increasing permeability k = k2r2 and derive the analytical expression of the stream function within the porous aggregate by incorporating the Brinkman and continuity equations. The hydrodynamic properties of the aggregate are investigated by taking account of the hydrodynamic radius, settling velocity, and fluid collection efficiency, which are found to be solely dependent on the permeability prefactor k2. The fractal dimension Df and prefactor k2 of the ideal aggregate are found to be 5/3 (=1.67) and 0.20, respectively, and well describe the hydrodynamics of aggregates formed in the diffusion-limited-cluster-aggregation (DLCA) regime. More important, hydrodynamic similarity between the ideal aggregate and impermeable solid sphere is discovered in terms of variations of the hydrodynamic radius, settling velocity, and fluid collection efficiency with respect to the aggregate radius. Keywords: Aggregation; Fractal aggregate; Permeability; Settling velocity; Hydrodynamic radius The immediate effects of hurricane Iniki on interidal fauna on the south shore of Oahu Dreyer, J., H. Bailey-Brock, and S,A, McCarthy No AbstractValidity of the generalized Richards equation for the analysis of pumping test data for a coarse-material aquifer El-Kadi, Aly I. This paper presents an examination of the validity of the generalized Richards equation (GRE), which includes unsaturation and compressibility effects, in the analysis of a well-documented, three dimensional aquifer test. The potential effects of wellbore storage and monitoring-well delayed response were included in the analysis. The uniqueness of the solution was also examined by testing the potential success of fully saturated models in simulating the drawdown measurements. The solution of the GRE closely matched the field measured drawdowns with some parameters that were close to their independently measured values. The aquifer-test analysis can thus provide accurate estimates for some average aquifer parameters, namely, horizontal and vertical hydraulic conductivities and specific storage. However, the model is not fully validated due to the need for calibrated soil hydraulic parameters. In general, it is possible to account for early time discrepancies by using an inflated fitting value for the specific storage. However, good accuracy was obtained using a physically based value for such a parameter when wellbore storage is considered. Sensitivity of results to values of saturated conductivity again confirmed the great importance of obtaining accurate estimates of such values. Finally, the study showed that saturated flow models did not provide results as accurate as those provided by the GRE model. Classifying the aquifer material as coarse can be misleading, considering that its effective soil properties is that of a finer texture. As such, unsaturated flow effects should not be overlooked.Screening of polymers on selected Hawaii soils for erosion reduction and particle settling James A. Teo, Chittaranjan Ray, and Samir A. El-Swaify In recent years, high-molecular-weight anionic polyacrylamides (PAMs) have been tested on a variety of soils, primarily in temperate climates. However, little information is available regarding the effectiveness of PAM for preventing soil loss through runoff in tropical settings. Screening tests were performed using three negatively charged PAMs and one positively charged PAM on five Hawaii soils (two Oxisols, one Vertisol, and two Aridisols) to determine erosion loss, sediment settling, and aggregate stability. A laboratory-scale rainfall simulator was used to apply erosive rainfall at intensities from 5 to 8.5 cm h-1 at various PAM doses applied in both dry and solution forms. Soil detachment due to splash and runoff, as well as the runoff and percolate water volumes, were measured for initial and successive storms. The impact of PAM on particle settling and aggregate stability was also evaluated for selected soil-treatment combinations. Among the PAMs, Superfioc A-836 was most effective, and significantly reduced runoff and splash sediment loss for the Wahiawa Oxisol and Pakini Andisol at rates varying between 10 and 50 kg hat. Reduced runoff and splash sediment loss were also noted for PAM Aerotil-D when applied in solution form to the Wahiawa Oxisol. Significant reductions in soil loss were not noted for either the Lualualei Vertisol or the Holomua Oxisol. It is believed that the high montmorillonite content of the Lualualei Vertisol and the low cation-exchange capacity of the Holomua Oxisol diminished the effectiveness of the various PAMs tested. The polymers were also found to enhance sediment settling of all soils and helped improve their aggregate stability. This screening study shows the potential use of PAM for tropical soils for applications such as infiltration enhancement, runoff reduction, and enhanced sedimentation of detention ponds. A new model for calculating specific resistance of aggregated colloidal cake layers in membrane filtration processes Kim, Albert S., Rong Yuan A simple model to evaluate hydrodynamic cake resistance due to filtered aggregates is developed in this study. An aggregate is treated as a hydrodynamically as well as geometrically equivalent solid core with a porous shell. Creeping flow past a swarm of the composite spheres is solved using Stokes’ equation and Brinkman’s extension of Darcy’s law. The dimensionless drag force () exerted on the composite sphere is analytically determined by four parameters: radius of the solid core, thickness of the porous shell, permeability of the aggregate, and occupancy fraction as defined in this paper. In certain limiting cases, converges to pre-existing analytical solutions for (i) an isolated impermeable sphere, (ii) an isolated uniformly porous sphere, (iii) an isolated composite sphere, (iv) a swarm of impermeable spheres, and (v) a swarm of uniformly porous spheres. This expression is then used to predict the specific resistance of aggregate cake formed on membrane surfaces. Brownian dynamics, molecular dynamics, and Monte Carlo modeling of colloidal systems Chen,Jim C., Albert S. Kim This paper serves as an introductory review of Brownian Dynamics (BD), Molecular Dynamics (MD), and Monte Carlo (MC) modeling techniques. These three simulation methods have proven to be exceptional investigative solutions for probing discrete molecular, ionic, and colloidal motions at their basic microscopic levels. The review offers a general study of the classical theories and algorithms that are foundational to Brownian Dynamics, Molecular Dynamics, and Monte Carlo simulations. Important topics of interest include fundamental theories that govern Brownian motion, the Langevin equation, the Verlet algorithm, and the Metropolis method. Brownian Dynamics demonstrates advantages over Molecular Dynamics as pertaining to the issue of time-scale separation. Monte Carlo methods exhibit strengths in terms of ease of implementation. Hybrid techniques that combine these methods and draw from these efficacies are also presented. With their rigorous microscopic approach, Brownian Dynamics, Molecular Dynamics, and Monte Carlo methods prove to be especially viable modeling methods for problems with challenging complexities such as high-level particle concentration and multiple particle interactions. These methods hold promising potential for effective modeling of transport in colloidal systems. Aquaculture wastewater treatment and reuse by wind-driven reverse osmosis membrane technology Qin, Gang, Clark C.K. Liu, et al. Nitrogen in aquaculture wastewater may cause many environmental problems to the receiving water. To protect its pristine coastal water, the State of Hawaii established stringent water quality limits for aquaculture wastewater. Effluents from aquaculture facilities in Hawaii generally exceed these limits - sometimes by one to two orders of magnitude. Development of cost-effective treatment technology would be one of the most important factors for a profitable aquaculture industry in Hawaii. Furthermore, recirculating of aquaculture wastewater is highly desirable for environmental protection and resource conservation. To achieve these goals, a wind-driven reverse osmosis (RO) technology was developed and applied for the removal of nitrogenous wastes from the culture water of tilapia on Coconut Island, the home of the Hawaii Institute of Marine Biology, University of Hawaii at Manoa. A conventional multi-blade windmill is used to convert wind energy directly to hydraulic pressure for RO membrane operation. Aquaculture wastewater passing through the RO membrane is separated into permeate (freshwater) and brine (concentrated wastewater). The permeate is recirculated to the fish tanks, while the brine is collected for possible treatment or reuse. As a result, no wastewater discharge is made to the ambient coastal water. Testing results indicated that the prototype wind-powered RO system can process and recycle freshwater at a flux of 228-366 L/h, depending on wind speed. The nitrogen removal rate ranges from 90% to 97%, and the recovery rate of the RO membrane is about 40-56%. A preliminary cost analysis shows that the production of 1.0 m3 permeate from aquaculture wastewater would cost US$ 4.00. Further study will focus on the reuse of concentrates and on further enhancement of cost-effectiveness. Use of qualitative and quantitative information in neural networks for assessing agricultural chemical contamination of domestic wells Arabinda Mishra, Chittaranjan Ray, and Dana W. Kolpin A neural network analysis of agrichemical occurrence in groundwater was conducted using data from a pilot study of 192 small-diameter drilled and driven wells and 115 dug and bored wells in Illinois, a regional reconnaissance network of 303 wells across 12 Midwestern states, and a study of 687 domestic wells across Iowa. Potential factors contributing to well contamination (e.g., depth to aquifer material, well depth, and distance to cropland) were investigated. These contributing factors were available in either numeric (actual or categorical) or descriptive (yes or no) format. A method was devised to use the numeric and descriptive values simultaneously. Training of the network was conducted using a standard backpropagation algorithm. Approximately 15% of the data was used for testing. Analysis indicated mat training error was quite low for most data. Testing results indicated that it was possible to predict the contamination potential of a well with pesticides. However, predicting the actual level of contamination was more difficult. For pesticide occurrence in drilled and driven wells, the network predictions were good. The performance of the network was poorer for predicting nitrate occurrence in dug and bored wells. Although the data set for Iowa was large, the prediction ability of the trained network was poor, due to descriptive or categorical input parameters, compared with smaller data sets such as that for Illinois, which contained more numeric information. Usefulness of monitoring tropical streams for male-specific RNA coliphages Luther, Kartini, and Roger Fujioka The objective of this study was to evaluate the usefulness of monitoring streams in Hawaii for FRNA coliphages as a reliable indicator of sewage contamination. This study was undertaken as a result of our previous findings that monitoring streams in Hawaii for traditional faecal indicator bacteria (faecal coliform, Escherichia coll, enterococci) was not useful in determining when streams are contaminated with sewage, because environmental (soil) sources rather than sewage accounted for the high concentrations of faecal bacteria in streams. Two perennial streams, sewage and soil samples were monitored for traditional faecal indicator bacteria (faecal coliform, £ coll, enterococci) and FRNA coliphages. The results showed that sewage treatment processes and disinfection drastically reduced the concentrations of traditional faecal indicator bacteria but FRNA coliphages were still present in significant concentrations in the treated sewage effluents. These results indicate that monitoring sewage effluents and environmental waters for only traditional faecal indicator bacteria may not be adequately protective of human health effects. Ambient concentrations of traditional faecal indicator bacteria in soil and streams of Hawaii were consistently high but consistently low for FRNA coliphages, indicating that monitoring streams of Hawaii for FRNA coliphages can be used to determine when streams are contaminated with sewage. Modeling RBF Efficacy for mitigating chemical shock loads Ray, Chittaranjan Riverbank filtration (RBF) offers several advantages over the direct use of surface water. A number of dissolved and suspended contaminants of surface water—including pathogens and microscopic particles—are removed during passage of surface water through the river sediment–aquifer system. Many dissolved chemicals undergo biogeochemical reactions and dilution, leading to reductions in concentrations of parent species. This research examined the potential of RBF systems to attenuate chemical shock loads that may result from chemical spills or spring flooding in agricultural watersheds. Scenarios simulated both horizontal and vertical wells, with riverbed and bank hydraulic properties varying as a function of river stage. The solute transport equation considered a range of reaction parameters. Sensitivity analysis showed that the hydraulic conductivity of the riverbed or bank materials had a pronounced effect on filtrate quality. For materials with low hydraulic conductivity, the effect on filtrate quality would be minimal, and the lag time between the contaminant peak concentrations in the surface water and the pumped water would be significant. However, further biogeochemical modeling is needed to predict the fate of contaminants during their transit to the pumping wells. Use of backup vertical wells of selected laterals of a collector well could effectively mitigate the risks. Integrating entrapped mixed microbial cell (EMMC) process for biological removal of carbon and nitrogen from dilute swine wastewater Yang, P.Y., H.J. Chen, S.J. Kim An entrapped mixed microbial cell (EMMC) process was used to investigate the simultaneous removal of carbon and nitrogen from dilute swine wastewater. Cellulose triacetate was used as the matrix for entrapping the mixed microbial cells. The EMMC process was tested under various oxygen supply conditions (ratios of aeration to non-aeration times) and two types of carrier sizes (large and medium). Also, various pre-treatments with chemical coagulation, screen separation, and ammonium crystallization prior to the EMMC process and post-treatment following the EMMC process were investigated. It was found that at a hydraulic retention time of 30 hours and 1 hour of aeration and 1 hour of non-aeration, the EMMC process packed with medium carriers after the pre-treatment of ammonium crystallization exhibited the best total nitrogen removal efficiency of 95.1 ± 1.0% when compared to two other pre-treatment methods. The total chemical oxygen demand (TCOD) and soluble chemical oxygen demand removal efficiencies were 83.5 ± 2.2% and 84.1 ± 1.1%, respectively. Lime post-treatment provided TCOD and total phosphorus removal efficiencies of 59.6 ± 2.7% and 98.0 ± 0.5%, respectively. Thus, a cost analysis for ammonium crystallization pre-treatment, EMMC process, and post-treatment with lime was conducted. The unit cost for a 2,000-pig operation is ˜$4.91/pig/year. For the application of the EMMC process with the proposed pre- and post-treatments, a suitable farm size needs to be greater than a 2,000-pig operation. Because of the high efficiency and the simple operation of simultaneous carbon and nitrogen removal, the EMMC process has the potential for treatment of dilute swine wastewater in a land-limited area and can be manufactured as pre-fabricated wastewater treatment units. Modeling depth-variant and domain-specific sorption and biodegradation in dual-permeability media Ray, Chittaranjan, Tomas Vogel and Jaromir Dusek A dual-permeability model (S_1D_DUAL) was developed to simulate the transport of land-applied pesticides in macroporous media. In this model, one flow domain was represented by the bulk matrix and the other by the preferential flow domain (PFD) where water and chemicals move at faster rates. The model assumed the validity of Darcian flow and the advective-dispersive solute transport in each of the two domains with inter-domain transfer of water and solutes due to pressure and concentration gradients. It was conceptualized that sorption and biodegradation rates vary with soil depth as well as in each of the two flow domains. In addition to equilibrium sorption, kinetic sorption was simulated in the PFD. Simulations were conducted to evaluate the combined effects of preferential flow, depth- and domain-variant sorption, and degradation on leaching of two pesticides: one with strong sorption potential (trifluralin) and the other with weak sorption potential (atrazine). Simulation results for a test case showed that water flux in the PFD was three times more than in the matrix for selected storm events. When equilibrium sorption was considered, the simulated profile of trifluralin in each domain was similar; however, the atrazine profile was deeper in the PFD than in the bulk matrix under episodic storm events. With an assumption of negligible sorption in the PFD, both the atrazine and the trifluralin profiles moved twice deeper into the PFD. The simulated concentrations of the chemicals were several orders higher in the PFD than in the matrix, even at deeper depths. The volume fraction of the macropores and the sorption and biodegradation properties of the chemicals could also affect the amount of pesticides leaving the root zone. For an intense storm event, slow sorption reaction rates in the PFD produced higher breakthrough concentrations of atrazine at the bottom of the simulated soil profile, thus posing the risk for breakthrough of chemicals from the root zone. Three new species of Saccocirrus (Polychaeta: Saccorcirridae) from Hawaii. Bailey - Brock, Julie H., J. Dreyer, and R.E. Brock Three new species of saccocirrids from interstitial sand habitats off O'ahu, Hawai'i, are described. Two are from subtidal depths, 9-33 m, and the third is from the intertidal to 3.5 m deep on a fringing reef and at Hanauma Bay, the Marine Life Conservation District and public park. The two deeper-water species, Saccocirrus oahuensis, n. sp. and 5. waianaensis, n. sp., have 76-119 and 157-210 segments, respectively; they also have bilateral gonads but lack a pharyngeal pad. The third, S. alanhongi, n. sp., has 35-47 segments, unilateral gonads, and a muscular pharyngeal pad. These species are distinguished from 18 known Saccocirrus spp. by their unique chaetation, number of segments, presence or absence of ventral cilia, and pygidial adhesive structures. Saccocirrus oahuensis consumes foraminiferans, and S. alanhongi contained diatoms, unicellular algae, and ostracods. These species add to the interstitial fauna of O'ahu and cooccur with polychaetes Nerilla antennata (Nerillidae) and protodrilids (Protodrilidae), and Kinorhyncha. Saccocirrus alanhongi withstands almost daily disturbance by 600-1200 bathers per day entering the sandy swimming holes in the reef at Hanauma Bay. Protozoal and epitheliocystis-like infections in the introduced bluestripe snapper Lutjanus kasmira in Hawaii Work, Thierry M., Robert A. Rameyer, Geraldine Takata, Michael L. Kent The bluestripe snapper, or taape, was introduced into Hawaii in the 1950s and
has since become very abundant throughout the archipelago. As part of a health
survey of reef fish in Hawaii, we necropsied 120 taape collected from various
coastal areas south of Oahu and examined fish histology for extraintestinal
organisms. Forty-seven percent of taape were infected with an apicom-plexan
protozoan compatible with a coccidian. Infection was evident mainly in the spleen
and, less commonly, the kidney. Prevalence of this coccidian increased with
size of fish, and we saw no significant pathology associated with the organism.
Twenty-six percent of taape were also infected with an epitheliocystis-like
organism that occurred mainly in the kidney and, less commonly, the spleen.
In contrast to the coccidian, fish mounted a notable inflammatory response to
the epitheliocystis-like organism, and this inflammation appeared to increase
in severity with age. Prevalence of the epitheliocystis-like organism infection
increased with age, but infection was not seen in fish greater than 26.5 cm
fork length. The high prevalence of coccidial infection in introduced taape
prompts the concern that these organisms, along with the epitheliocystis-like
organism, have the potential to be transmitted to native reef fish. Given the
impact of other introduced microbial organisms on native Hawaiian fauna, there
is a clear need to assess whether protozoa and bacteria are endemic to Hawaii,
and whether they negatively impact native reef fish that closely associate with
taape. Rainwater roof catchment systems, microbial quality of Fujioka, Roger S. Clean and safe water piped to homes by a reliable supplier (water utility) and available at the turn of a tap is taken for granted by most people in developed countries. However, in developing countries, large populations of people are not supplied with clean water piped into their homes. Even in developed countries, many houses do not receive piped water from a public water utility because of practical or economical conditions related to houses being too far away from a public water utility, houses being located at too high an elevation, or because the houses in rural areas are too few and too scattered. Under these conditions, homeowners will rely on the most feasible source of water for their household needs, such as surface waters (rivers, streams, lakes) or groundwater sources (boreholes, wells). However, under some conditions these sources of water are not readily available, and harvesting (collecting and storing) rainwater may be the most feasible way to obtain water for household use. In its simplest form, open tanks can serve the dual purpose of collecting and storing rainwater. However, this method is applicable only to few places where rainfall is frequent and the volume of water required is low. In most situations, a designated surface area or catchment is required to collect sufficient volumes of rainwater. The objective of this review is to assess the microbial and hygienic quality of rainwater collected from roof catchment systems from private homes and stored in cisterns or tanks for household use. Monitoring Honolulu's groundwater sources for human enteric viruses using cell culture and cell-culture PCR Fujioka, Roger, Audrey Asahina, Geeta Rijal, and J. Alfredo Bonilla The Honolulu Board of Water Supply (HBWS) is the largest water utility in the state of Hawaii and chlorinates only 50% of its deep (600 feet) groundwater sources to provide 150 mgd of potable water. The water quality in the distribution system contains low to undetectable levels of chlorine but meets the Total Coliform Rule. However, the upcoming Groundwater Rule (GWR) recommends that groundwater sources be chlorinated to reach a 0.2 mg/l residual in the distribution system as a treatment process to disinfect contaminating pathogens. Guidance under the GWR indicate that water utilities may be granted a variance to this disinfection requirement if their groundwater sources are naturally protected and are not vulnerable to contamination with fecal matter. In a previous study, the groundwater sources used by HBWS were monitored for multiple fecal indicator microorganisms (total coliforms, fecal coliforms, E. coli, fecal streptococci, C. perfringens, FRNA coliphages). Since most of 79 groundwater samples did not contain these fecal indicator microorganisms, it was concluded that these groundwater sources are naturally protected from fecal matter. However, human enteric viruses are the most likely pathogen to contaminate groundwater and are known to survive longer and are transported more readily through the soil environment than fecal bacteria. The objective of this study was to analyze HBWS groundwater sources for human enteric viruses. The experimental design of this study was to process 200 gallons of groundwater and to analyze these samples for infectious human enteric viruses using the standard cell culture method as well as the integrated cell culture and polymerase chain reaction (ICC-PCR) method. A total of 45 groundwater sources were initially determined to be negative for human enteric viruses by cell culture method and by the standard ICC-PCR results. However, based on seeding poliovirus into mock samples, the standard ICC-PCR method was determined to be unreliable due to interferences from sample components. A modified ICC-PCR was developed to increase the sensitivity of the assay method. Using this modified method, 40 of the groundwater samples tested were shown to be negative for human enteric viruses. Two conclusions can be drawn from this study. First, that PCR methods must be optimized for each laboratory before they a re used. Second, the absence of human enteric viruses in all groundwater samples by cell culture and PCR method indicate that the groundwater sources used by the HBWS are not vulnerable to contamination by human enteric viruses. Male-specific RNA coliphages are reliable markers of sewage (point source) contamination Luther, K. and R. Fujioka Concentrations of U.S. Environmental Protection Agency-approved fecal indicator bacteria (fecal coliform, E. coli, enterococci) in environmental waters are used to determine the extent of sewage contamination and to establish recreational water quality standards. These water quality standards are used to determine the risk or probability that someone using that body of water for primary contact recreational use (e.g., swimming) will become ill from sewage-borne pathogens. The current EPA-recommended marine recreational water quality standards were developed from results of previously completed epidemiological and water quality studies at three beach sites (New York City, Boston Harbor, and Lake Pontchartrain) in the United States. These sites were selected because concentrations of fecal bacteria were barely acceptable due to nearby sewage discharges. Similar studies were conducted for fresh recreational waters at lakes in Pennsylvania and Oklahoma. Results of these studies (Cabelli et al., 1982; USEPA, 1986) have led to different recreational water quality standards for marine waters and for fresh waters. For marine waters, the EPA-recommended recreational water quality standard is a geometric mean concentration of 35 enterococci/100 ml based on five weekly samples taken over a month. For fresh waters, the EPA-recommended standards are similar geometric mean concentrations of 33 enterococci/100 ml or 126 E. coli/100 ml. The results of these EPA studies showed that concentrations of enterococci in marine and fresh waters correlated with incidences of swimming-associated gastroenteritis whereas concentrations of E. coli correlated with swimming-associated gastroenteritis only in fresh waters. A significant conclusion of the EPA studies was the finding that concentrations of fecal coliforms in marine and fresh waters did not correlate with swimming-associated gastroenteritis. EPA concluded that the most likely sewage-borne pathogens causing gastroenteritis was Norwalk type viruses (Cabelli et al., 1982). It was concluded that E. coli was too unstable in marine waters to serve as a reliable surrogate for the presence of sewage-borne pathogens. It should be noted that EPA conducted a similar epidemiological study at a lake in Connecticut. This lake was not contaminated with sewage, and fecal indicator bacteria in the lake were from non-point sources such as wild animals rather than from a point source (sewage). Under these conditions, the concentrations of enterococci and E. coli did not correlate with swimming-associated gastroenteritis (Calderon et al., 1991). Experiments of a prototype wind-driven reverse osmosis desalination system with feedback control Liu, Clark C.K., Jae-Woo Park, Reef Migita, and Gang Qin A prototype wind-powered reverse osmosis desalination system was constructed and tested on Coconut Island off the northern coast of Oahu, Hawaii, for brackish water desalination. The system has four major subsystems: a multi-vaned windmill/pump, a flow/pressure stabilizer, a reverse osmosis module, and a control mechanism. The feedback control mechanism, developed by this study, allowed this prototype system to be operated satisfactorily under mild ambient wind of 5 m/s or less. No auxiliary power source was needed. The system operational data showed that at an average wind speed of 5 m/s, brackish feedwater at a total dissolved solids concentration of 3000 mg/l and at a flow rate of 13 l/min could be processed by this system. The average rejection rate of this prototype system was 97% and the average recovery ratio as 20%. The energy efficiency of the system was measured at 35%, which is comparable to the typical energy efficiency of well-operated multi-vaned windmills. Generally, the system's energy efficiency decreases as wind speed increases. Artificial upwelling and near-field mixing of deep-ocean water effluent Liu, Clark C.K, In Mei Sou, and Huashan Lin Deep-ocean water (DOW) as a depth of 300 m or lower is cold, nutrient-rich, and free of pathogenic bacteria. This water is considered an important natural resource. One of the fully developed technologies of DOW application is ocean thermal energy conversion (OTEC), which makes use of DOW for energy production. In recent years, the potential of DOW to enrich the open oceans and thus to increase fish yield has attracted the attention of researchers. Before this potential can be realized, however, major scientific and technological developments concerning artificial upwelling, plume mixing, and DOW simulated bio-productivity must be achieved. This study, which is a continuation of earlier research on artificial upwelling at the University of Hawaii, investigates the effects of discharging artificially upwelled DOW into the open ocean where it is subsequently mixed with surface water. The study involves both hydraulic modeling and numerical simulation, and its objective is to control the near-field mixing of DOW effluent such that the dilution is small and the settling depth does not go below the euphotic zone. Special attention is given to wave effects on the near-field mixing processes. Research results indicate that, with proper effluent control, desirable nutrient-rich DOW plumes can be established and maintained in the open ocean. Polychaetes associated with a tropical ocean outfall: Synthesis of a biomonitoring program off O‘ahu, Hawai‘i Bailey–Brock, J.H., B. Paavo, B.M. Barrett, and J. Dreyer A comparison of benthic polychaete communities off the Sand Island Wastewater Outfall was undertaken to recognize organic enrichment indicator species for Hawaiian waters. Primary-treatment sewage is discharged off the south shore of O'ahu at 70 m depth. A historical data set spanning 9 yr for seven sites at 70 m and two recent studies at 20, 50, and 100 m depths were analyzed. Geochemical data did not support the assumption that the outfall is an im¬portant source of organic enrichment in nutrient-poor sandy sediments within oligotrophic tropical waters. Five polychaete species, however, appeared partic¬ularly sensitive, positively or negatively, to environmental conditions near the outfall. Neanthes arenaceodentata (Nereididae) and Ophryotrocha adherens (Dorvilleidae) have been dominant at sites within the outfall's zone of initial dilution (ZID). Since 1993, N. arenaceodentata has virtually disappeared, and O. adherens concurrently became abundant and continued to flourish at ZID sites. Well-known indicators within the Capitella capitata complex (Capitellidae) were pres¬ent at ZID and control (far field) sites though their ZID abundance was greater. Two sabellids, Euchone sp. B and Augeneriella dubia were inversely distributed, the smaller Euchone sp. B at far field sites and larger A. dubia within ZID stations. The former was most likely restricted to a greater proportion of fine sed¬iment particles at two far field sites. The most abundant and widespread polychaete off O'ahu's south shore was Pionosyllis heterocirrata (Syllidae), which does not seem to represent a sensitive indicator species. Ophryotrocha adherens was the most abundant indicator species within the ZID; P. heterocirrata was the most ubiquitous species at all sites and should always be expected in these sedi¬ments. Traditional measurements of numerical abundance, species richness, and diversity (H') have not shown a clear distinction between ZID and far field sites in annual analyses. An examination of composited data over an 11-yr period does support such a distinction. Multidimensional scaling (MDS) analyses clearly delineate different assemblages. We suggest that MDS analyses are sen¬sitive to the community differences present near the outfall. The ZID commu¬nity is clearly contained within the Environmental Protection Agency-approved ZID boundary. Because each ZID and far field site supports a diverse and coarsely similar polychaete fauna, no pollution level effects seem to be present. Use of reflectors to enhance the synergistic effects of solar heating and solar wavelengths to disinfect drinking water sources Rijal, G.K. and R.S. Fujioka Aluminum reflectors were added to solar units designed to inactivate faecal microorganisms (faecal coliform, E. coli, enterococci, FRNA coliphage, C. perfringens) in stream water and diluted sewage by the two mechanisms (solar heat, solar UV) known to inactivate microorganisms. During sunny condition, solar units with and without reflectors inactivated E. coli to <1 CFU/100 ml to meet drinking water standards. Solar units with reflectors disinfected the water sooner by increasing the water temperature by 8–10oC to 64–75oC. However, FRNA coliphages were still detected in these samples, indicating that this treatment may not inactivate pathogenic human enteric viruses. During cloudy condition, reflectors only increased the water temperature by 3–4oC to a maximum of 43–49oC and E. coli was not completely inactivated. Under sunny and cloudy conditions the UV wavelengths of sunlight worked synergistically with increasing water temperatures and were able to disinfect microorganisms at temperatures (45–56oC), which were not effective in inactivating microorganisms. Relative resistance to the solar disinfecting effects were C. perfringens > FRNA coliphages > enterococci > E. coli> faecal coliform. Microbial indicators of marine recreational water quality Fujioka, Roger S. The value of coastal waters is clearly evident from the ob¬servation that nearly two-thirds of the world's population make their homes within 150 km of the shore (31). The obvious advantages of living near coastal areas are a mod¬erate climate, ease of transportation, sources of food, and jobs. However, when people live near coastal water, they also develop social and cultural values associated with coastal waters (20). More recently, people have recognized the esthetic and recreational values of coastal waters. As a result, people today travel long distances to spend their valuable vacation time at coastal water sites which are especially suitable for swimming, sunbathing, surfing, and fishing. To meet all of these values of coastal waters, there has been a dramatic increase in the building of cities, industries, homes, hotels, restaurants, shops, parks, harbors, and many tourist-related facilities in coastal areas. Unfortunately, these activities, along with the commensurate increase in population, inevitably result in increased production of point source pollution such as sewage and industrial discharges as well as nonpoint source pollution such as agricultural and urban runoff, especially storm drains. In coastal areas, these kinds of pollution generally discharge into and pollute coastal waters (40). Recognizing this problem, effective environmental regulations have been implemented to properly treat and dispose of point source discharges. However, nonpoint source discharges have generally not been regulated, and therefore these kinds of discharges are not treated and pollute shoreline coastal waters, often in close proximity to waters desig¬nated for swimming. In this regard, a recent report by the U.S. Environmental Protection Agency (EPA) estimates that the water quality at 40% of the nation's recreational waters is unsuitable for swimming and that contamination is due primarily to nonpoint source pollution (Beach Watch website: http://www.epa.gov/ost/beaches). Today, many of our popular beaches are susceptible to pollution, and the suitability of these waters for swimming is often questioned. Diseases acquired from recreational use of wa¬ters are of great concern to city officials, public health agencies, and the tourism industry. To address this concern, expensive programs have been implemented to control coastal water pollution, to establish water quality standards, and to constantly monitor these waters to ensure that rec¬reational waters designated for swimming are suitable for swimming. Linear systems approach to river water quality analysis Liu, Clark C.K. and Jenny Jing Neill The water quality of a polluted river can be improved either by increasing the river's self-purification ability or by reducing the amount of waste loading the river receives. Traditional physically based water quality models do not evaluate separately a receiving river's purification ability and the effect of waste loading; thus, these models are not ideal analytical tools for water quality management. This chapter introduces and discusses an alternative river water quality modeling approach based on the linear systems theory. In a linear systems model, a receiving river's self-purification ability is represented completely by the model's, impulse response function, whereas the amount of waste loading the river receives is represented by the model's input function. These two functions can be evaluated separately. Further, a simple convolution integration of these two functions gives the system output. Usually, the system output is the water quality condition of the receiving river. The linear systems model's usefulness as a water quality management tool is demonstrated in this chapter by applying it to studies of dissolved oxygen variations (1) in a steady-state river system that receives both point-source and nonpoint-source waste loading and (2) in a time-variable river system that receives point-source waste loading in the form of periodic function. Monitoring coastal marine waters for spore-forming bacteria of faecal and soil origin to determine point from non-point source pollution Fujioka, R.S. The US Environmental Protection Agency (USEPA) and the World Health Organization (WHO) have established recreational water quality standards limiting the concentrations of faecal indicator bacteria (faecal coliform, E. coli, enterococci) to ensure that these waters are safe for swimming. In the application of these hygienic water quality standards, it is assumed that there are no significant environmental sources of these faecal indicator bacteria which are unrelated to direct faecal contamination. However, we previously reported that these faecal indicator bacteria are able to grow in the soil environment of humid tropical island environments such as Hawaii and Guam and are transported at high concentrations into streams and storm drains by rain. Thus, streams and storm drains in Hawaii contain consistently high concentrations of faecal indicator bacteria which routinely exceed the EPA and WHO recreational water quality standards. Since, streams and storm drains eventually flow out to coastal marine waters, we hypothesize that all the coastal beaches which receive run-off from streams and storm drains will contain elevated concentrations of faecal indicator bacteria. To test this hypothesis, we monitored the coastal waters at four beaches known to receive water from stream or storm drains for salinity, turbidity, and used the two faecal indicator bacteria (E. coli, enterococci) to establish recreational water quality standards. To determine if these coastal waters are contaminated with non-point source pollution (streams) or with point source pollution (sewage effluent), these same water samples were also assayed for spore-forming bacteria of faecal origin (C. perfringens) and of soil origin (Bacillus species). Using this monitoring strategy it was possible to determine when coastal marine waters were contaminated with non-point source pollution and when coastal waters were contaminated with point source pollution. The results of this study are most likely applicable to all countries in the warm and humid region of the world. Synergistic effect of solar radiation and solar heating to disinfect drinking water sources Rijal, G.K. and R.S. Fujioka Waterborne diseases are still common in developing countries as drinking water sources are contaminated and feasible means to reliably treat and disinfect these waters are not available. Many of these developing countries are in the tropical regions of the world where sunlight is plentiful. The objective of this study was to evaluate the effectiveness of combining solar radiation and solar heating to disinfect contaminated water using a modified Family Sol-Saver System (FSP). The non-UV transmittable cover sheet of the former FSP system was replaced with an UV transmittable plastic cover sheet to enable more wavelengths of sunlight to treat the water. Disinfection efficiency of both systems was evaluated based on reduction of the natural populations of faecal coliform, E. coli, enterococci, C. perfringens, total heterotrophic bacteria, hydrogen sulphide producing bacteria and FRNA virus. The results showed that under sunny and partly sunny conditions, water was heated to critical temperature (60°C) in both the FSP systems inactivating more than 3 log (99.9%) of the concentrations of faecal coliform and E. coli to undetectable levels of <1 CFU/100 mL within 2–5 h exposure to sunlight. However, under cloudy conditions, the two FSP systems did not reduce the concentrations of faecal indicator bacteria to levels of <1 CFU/100 mL. Nonetheless, sufficient evidence was obtained to show that UV radiation of sunlight plus heat worked synergistically to enhance the inactivation of faecal indicator bacteria. The relative log removal of indicator microorganism in the FSP treated water was total heterotrophic bacteria < C. perfringens < FRNA virus < E. coli< faecal coliform. In summary, time of exposure to heat and radiation effects of sunlight were important in disinfecting water by solar units. The data indicated that direct radiation of sunlight worked synergistically with soar heating of the water to disinfect the water. Thus, effective disinfection was observed even when the water temperature did not reach 60°C. Finally, the hydrogen sulphide test is a simple and reliable test that householders can use to determine whether their water had been sufficiently disinfected. Wastewater reuse Liu, Clark C.K. Recent events and research on wastewater reuse are covered. Video transects and their use in the environmental assessment of deep water marine disposal sites Miller, Jacquelin N., Roy H. Wilkens, and Peter Wathern Environmental studies of proposed or designated disposal sites are directed by regulations that presently require extensive sampling of all possible components of biological, chemical, and physical characteris¬tics of the sites with little regard for the application of this data to predicting real, as contrasted to perceived, impacts to the environment. These broad-brush studies are poorly focused, may provide little guidance for measuring actual impacts, and are extremely costly. To address these problems, a new method of carrying out environmental assessments of deep water dredged material disposal sites has been developed that incorporates the latest developments in both video imaging and computer analysis as well as selective, habitat based, sampling. Microbial ecology controls the establishment of fecal bacteria in tropical soil environment Fujioka, R.S. and M.N. Byappanahalli Fecal indicator bacteria such as E. coliand enterococci are consistently present in Hawaii's streams in concentrations exceeding recreational water quality standards. The source of these fecal indicator bacteria has been determined to be the soil where these bacteria are able to multiply and have become part of the soil microflora. The mechanisms by which these fecal bacteria are able to multiply under ambient soil conditions have not been determined. The objective of this study was to test two hypotheses by which these fecal bacteria can establish populations in the soil environment. The first hypothesis states that the soil environment is restrictive for the growth of fecal bacteria but a sub-population of fecal bacteria with metabolic characteristics adaptable to growth in soil will be selected to establish a population. The second hypothesis states that the soil environment is permissive and most strains of fecal bacteria will be able to multiply and become part of the soil microflora. The metabolic profile of soil isolates of 48 E. coli and 30 enterococci were determined based on their ability to metabolize 95 different carbon sources using the Biolog System. These results showed that many metabolically diverse strains of E. coli as well as six different species of Enterococcus were recovered from seven different groups of soil in Hawaii. These results support the hypothesis that soil conditions in Hawaii are permissive for the growth of most strains of fecal bacteria. Thus, the genetic capabilities of fecal bacteria are sufficiently robust to overcome all of the ecological constraints in the soil environment and have succeeded in becoming a minor but significant fraction of the soil microflora. Assessing the vulnerability of groundwater sources to fecal contamination Fujioka, Roger S. and Bunnie S. Yoneyama The Honolulu Board of Water Supply (HBWS) selectively chlorinates half of its groundwater supply to provide drinking water that meets the Total Coliform Rule. The objective of this study was to determine whether the groundwater sources used by HBWS are vulnerable to contamination with fecal matter and would require routine disinfection. Larger volumes (1,000 ml) of samples from groundwater and from the distribution system were more sensitive than standard volumes (100 ml) in the detection for total coliform, fecal coliform, Escherichia coli, and fecal streptococcus. Confirmed fecal indicator bacteria were detected in 2 of 79 groundwater samples and from none of the 152 distribution system water samples, indicating that the groundwater has a low incidence of contamination and the selective chlorination program effectively reduces this level of contamination. Analysis of 1,000-ml samples of groundwater is recommended but is not included in the recent guidelines of the proposed Ground Water Rule. One last visit to the capillarity correction for free surface flow Fink, James P., J.-Y. Parlange, and Aly I. El-Kadi When a capillarity correction is incorporated into the diffusion equation to describe the sudden drawdown of a water table, the resulting differential equation preserves, instead of smoothes, irregularities in the initial data. We describe how this problem can be handled by a proper and careful interpretation of the initial conditions, explain why it works, and illustrate the resulting behavior with numerical experiments. Identifying variably saturated water-flow patterns in a steep hillslope under intermittent heavy rainfall El-Kadi, Aly I. and Jill D. Torikai The objective of this paper is to identify water-flow patterns in part of an active landslide, through the use of numerical simulations and data obtained during a field study. The approaches adopted include measuring rainfall events and pore-pressure responses in both saturated and unsaturated soils at the site. To account for soil variability, the Richards equation is solved within deterministic and stochastic frameworks. The deterministic simulations considered average water-retention data, adjusted retention data to account for stones or cobbles, retention functions for a heterogeneous pore structure, and continuous retention functions for preferential flow. The stochastic simulations applied the Monte Carlo approach which considers statistical distribution and autocorrelation of the saturated conductivity and its cross correlation with the retention function. Although none of the models is capable of accurately predicting field measurements, appreciable improvement in accuracy was attained using stochastic, preferential flow, and heterogeneous pore-structure models. For the current study, continuum-flow models provide reasonable accuracy for practical purposes, although they are expected to be less accurate than multi-domain preferential flow models. System development and testing of wind-powered reverse osmosis desalination for remote Pacific islands Liu, C.C.K., R. Migita, and J.-W. Park Reverse osmosis (RO) is one of the most feasible methods of desalination to produce a supplemental freshwater supply. Because traditional RO desalination is energy-intensive, it is not a viable solution for remote Pacific islands where electricity is also in short supply. The utilization of wind power holds promise as a solution to this problem, as most of these remote islands are subject to constant trade winds. RO desalination of brackish groundwater, which is available in many of these islands, requires low feed water pressure that can be delivered by wind power at a moderate wind speed. Testing of a prototype wind-powered RO desalination system constructed on Coconut Island, a small island off the windward coast of Oahu, Hawaii, indicated that at an average wind speed of 8.5 m/s, a freshwater flow of over 4000 L/d can be produced. This volume is sufficient to meet the freshwater needs of a typical remote island community. Keywords Brackish water; reverse osmosis; system control; wind power Changes in pollution indicators at the Sand Island sewage outfall Bailey–Brock, Julie H., Brian Paavo, Brendan M. Barrett, and Jennifer Dreyer Comparison of benthic communities off the Sand Island Ocean Outfall was undertaken to recognize pollution indicator species for Hawaiian waters. The primary treatment sewage is discharged off the south shore of O'ahu at 70m depth. A historical data set spanning 15 years for seven sites at 70m (4 ZED and 3 far field) and two recent studies at 20, 50, and 100m were compared. Polychaetes collected with a 7.6 cm diameter sediment core were sorted and five indicator species tentatively identified. Neanthes arenaceodentata (F. Nereididae) and Ophryotrocha adherens (F. Dorvilleidae) have been dominant at ZID stations. Since 1993, N. arenaceodentata has virtually disappeared from the ZID while O. adherens became abundant and continues to flourish there. The well known indicators within the Capitella capitata complex (F. Capitellidae) are present at ZID and far field sites. Two sabettids, Euchone sp. B and Augeneriella dubia are inversely distributed, the smaller Euchone sp. B at the far field stations and larger A. dubia at the ZID. The former is most likely restricted to the greater proportion of fine sediment particles at two far field sites. Pionosyllis heterocirrata (F. Syllidae) is the most abundant and widespread polychaete off O'ahu's south shore. These indicator species share life history and feeding traits that lead to rapid growth and onset of reproduction, and produce benthic juveniles that recruit to the parent population leading to high levels of abundance. The success of indicator species is due to rapid use of available food resources and resulting increase in abundance. O. adherens is the most abundant indicator species at the ZID, P. heterocirrata is the most ubiquitous species at all sites and should always be present in these sediments. No pollution level effects on the benthic assemblages seem to be present, but fluctuations in indicator abundances may indicate a response to organic materials such as sewage outfalls. Future changes in benthic assemblages on O'ahu's south shore need to consider all possible organic sources including sewage effluent, fish farm wastes, land run off, canal and harbor drainage and the effects of beach nourishment projects. Development and assessment of a fecal bacterial monitoring program to determine the impact of ocean sewage outfall on shoreline water quality Fujioka, R., C. Fujioka, and R. Oshiro An innovative monitoring study, based on analyzing water samples at sampling stations near the Sand Island Ocean Outfall for three fecal indicator bacteria (E. coli, enterococci, and C. perfringens), was completed. Monitoring for these bacteria was useful because each is present in wastewater at different concen¬trations and survives in ocean water environments at different rates. The wastewater being discharged into the ocean via the ocean outfall pipe was documented to contain high concentrations of the three fecal bacteria. The monitoring data were used to assess the movement of fecal bacteria from the ocean outfall to shoreline stations where most people use the water for recreational purposes. Data were obtained to show that the wastewater from the ocean outfall did not surface but remained submerged to be transported away by ocean currents and be further diluted by ocean water. Since the concentrations of fecal bacteria at the Nearshore Stations and at the Shoreline Stations met the current recreational water quality standards, it was concluded that the wastewater discharged from the Sand Island Ocean Outfall was not being transported to the Shoreline Stations to measurably impact on the microbial quality of water there. Nonpoint sources of fecal bacteria can affect shoreline water quality. Instances of elevated fecal bacterial counts at the Nearshore Stations were observed, indicating that the wastewater from the ocean outfall was occasionally being transported to the Nearshore Stations. The difficulty of interpreting a single day of elevated counts and the many complications involved in interpreting monitoring data near ocean sewage outfalls were reviewed. Macrobenthos monitoring near the Sand Island and Barbers Point Ocean Outfalls, O‘ahu, Hawai‘i Swartz, R.C., J.H. Bailey–Brock, W.J. Cooke, and E.A. Kay The Sand Island and Barbers Point primary treatment plants discharge wastewaters into Mamala Bay through ocean outfalls located off the southern coast of O'ahu, Hawai'i at a water depth of approximately 60 m. The macrobenthos in the vicinity of these outfalls has been monitored since 1986. Replicate grabs at multiple stations located along transects and depth contours have been collected to provide biological samples for quantitative analyses. Samples for analysis of sediment grain size and parameters of sediment organic enrichment have also been collected. Benthic conditions at sites near the outfalls have been compared with reference conditions at sites 3 to 6 km from the outfalls to assess biological changes that might be related to the wastewater discharges. The structure of mollusk, nonmollusk (all macrobenthos excluding mollusks), and crustacean assemblages has been analyzed separately. Parameters of biological conditions include number of individuals, number of species, diversity (H1), evenness (J), faunal similarity (Bray-Curtis index), indicator species, and dominant species composition. Conditions have been compared in space (among stations from a single survey) and in time (among samples from different surveys; usually conducted near each outfall on an annual basis). Sediments, which were composed primarily of fine to coarse sands, showed no evidence of organic enrichment at any station. A diverse and abundant macrobenthos has been sampled near the two outfalls. Samples from each survey typically contained hundreds of benthic taxa and more than 10,000 individuals. Analyses of the abundance, taxa richness, and diversity of mollusks and nonmollusks almost always showed no statistically significant reductions at sites near the outfalls relative to reference sites. The abundance and taxa richness of crustaceans have often been less, but usually not significantly less, at some stations near the outfalls. The collection of a variety of pollution-sensitive amphipods near the outfalls indicates that the diminished crustacean fauna may be due to a noncontaminant factor. Separate cluster analyses of mollusks and nonmollusks indicate that factors associated with water depth are more closely related to faunal similarity than proximity to the outfalls. Long-term temporal trends show increased macrobenthic abundance. In summary, the weight of evidence indicates the Sand Island and Barbers Point discharges have not caused substantial changes in the macrobenthos. Occurrence of herbicides and their degradates in Hawaii's groundwater Li, Qing X., Eul-Chul Hwang, and Fengmao Guo Hawaii, with its isolated insular location, unrelenting pest pressure, and complex volcanic geology, presents many unique challenges to protecting groundwater from pesticide contamination. The U.S. Environmental Protection Agency (EPA) estimated that about 10% of community water system wells and 4% of rural domestic wells in the U.S. contain at least one pesticide or pesticide degradation product (degradate) at the reporting limits of the survey (EPA 1990). Regular sampling of community water systems show pesticides and pesticide degradates in 68 of 457 drinking water sources in Hawaii (State of Hawaii Department of Health 1996). The previous monitoring primarily focused on fumigants such as ethylene dibromide and trichloropropane, triazine herbicides, and chlorinated insecticides such as dieldrin and lindane. The most frequently reported pesticides in Hawaii's groundwater are fumigants used in pineapple fields, triazine herbicides used in sugarcane fields and termiticides. Agriculture in Hawaii is in a change from plantation to small family farms. Various pesticides have been used to control different pests. A recent study categorized a wide range of pesticides as "teachers" or "non-leachers" for a specific Hawaii hydrogeological setting. This study was to monitor the occurrence of some herbicides found in groundwater in the continental U.S. in selected wells in Hawaii. These include alachlor, bromacil, dacthal, hexazinone, metolachlor, metribuzin, atrazine, ametryn and simazine and their degradates. Findings in this study have supported the log-transformed attenuation factor index ranking as a practical predication means to assist decision-making Modeling hydrocarbon biodegradation in tidal aquifers with water-saturation and heat inhibition effects El-Kadi, Aly I. A model is developed for hydrocarbon biodegradation, which includes saturated and unsaturated flow, multi-species transport, heat transport, and bacterial growth processes. Numerical accuracy of the model was tested against analytical solutions. The model was also verified against laboratory results for a saturated-flow problem and reasonable match was obtained. Expressions are proposed for inhibition due to water content and temperature fluctuations. Bioactivities under cyclic water content variation were studied under no-flow conditions. A quantitative approach was used to reconcile some of the apparent contradictory conclusions regarding the efficiency of biodegradation of soils under wetting and drying conditions. The efficiency depends on the nature of the oxygenation process. For cases involving the presence of dissolved oxygen and the absence of O2 vapor, subjecting the soil to constant water content close to its optimal value for degradation is most efficient. However, wetting and drying can enhance degradation if O2 is only provided through aeration or direct contact between air and the medium. Also presented are the results of a typical field application of the model and a discussion of the effects of tides, saturation inhibition, and heat inhibition. Other inhibition factors, such as pH or salinity, can be easily incorporated in the formulation. The quantitative approach developed here can be used in assessing bioremediation not only in tidal aquifers but also in areas where water-table or temperature effects are of significance. The approach can be useful in the design of remediation strategies under water-flow or no-flow conditions involving water content and temperature fluctuations. Hawaiian Phoronida (Lophophorata) and their distribution in the Pacific region Bailey-Brock, Julie H., and Christian C. Emig Five Phoronis species are found in Hawaiian waters. Three were recorded previously, and two others, P. muelleri and P. pallida, are added here. Phoronis ovalis (the smallest) and P. hippocrepia are perforant species forming burrows in coral rock, shells, and barnacle encrustations, and P. psammophila, P. muelleri, and P. Pallida are sand-dwellers. Species diagnosis in phoronids requires sectioning to estimate muscle formulas and arrangement of other internal organs. Included are a key to Hawaiian species based on visible external features (so not entirely accurate), description of each, and distribution in Hawaiian waters and the Pacific Ocean. Morphology and life history of Ophryotrocha adherens sp. nov. (Polychaeta, Dorvilleidae) Paavo, Brian, Julie H. Bailey-Brock, and Bertil Akesson An undescribed dorvilleid belonging to the genus Ophryotrocha, Chaparede & Mecznikow, has been collected in the harbor of Kyrenia, Cyprus, the harbor of Las Palmas, and the Canary Islands. It also has recently been reported from the Sand Island and Barbers Point sewage outfalls (Oahu, Hawaii) during an ongoing benthic biomonitoring program. Previous investigations of possible indicator species suggest it may be an outfall-associated species. The species has been continuously cultured since 1971 in Sweden and since 1993 in Hawaii. It has been documented by previous authors under the name Ophryotrocha adherens. These laboratory cultures have produced a profile of the species' life history. The basic reproductive pattern, which includes a short-term free-swimming larva and brood protection within a flexible mucous cocoon, was revealed in a life table study. A full description of O. adherens morphology is presented here, including results of light and scanning electron microscopy of parapodia, setae, cilia, and dentition. Recent community studies have shown that O. adherens abundances decrease with increasing distance from primary treatment sewage outfalls over the past eight years. Rapid reproductive response to organic enrichment makes O. adherens a candidate for marine sediment bioassays. Immunochemical detection of polycyclic aromatic hydrocarbons and 1-hydroxypyrene in water and sediment samples Li, Kai, Lee Ann Woodward, Alexander E. Karu, and Qing X. Li Several approaches were investigated to fully use an enzyme-linked immunosorbent assay (ELISA) for accurate measurement of polycyclic aromatic hydrocarbons (PAHs) and their degradation products in surface water and sediments collected from the Pearl Harbor and James Campbell National Wildlife Refuges (NWRs) in Hawaii. Water samples were extracted by solid phase extraction (SPE) while the sediments were extracted by supercritical CO2. Parent PAHs and 1-hydroxypyrene, selected as a marker, were quantitatively recovered with supercritical CO2 from sediments that were mixed with 5% Na4EDTA. Use of Na4EDTA or Na2SiO3 significantly improved recovery of 1-hydroxypyrene in sediments. Na4EDTA was more effective than Na2SiO3. The concentrations of PAHs as benzo[a]pyrene equivalents determined by ELISA were slightly higher than those determined by gas chromatography; mass spectrometry (GC/MS). Overestimation' by ELISA over GC/MS was attributed to, at least in part, the presence of PAH metabolites including 1-hydroxypyrene which were detected by ELISA, but not quantified by GC/MS. Sunlight inactivation of human enteric viruses and fecal bacteria Fujioka, R.S., and B.S. Yoneyama Three human enteric viruses (poliovirus, echovirus, coxsackievirus) suspended in seawater or buffer were stable for 6 hours in the absence of sunlight but were inactivated at the same rate in the presence of sunlight. Under summer sunlight conditions, at least 3 logs of these viruses were inactivated by one-hit kinetics, whereas under winter sunlight conditions, only 1 log of these viruses was inactivated by two-hit kinetics. Under these same conditions, 6 logs of E. coli were inactivated within 1 hour by one-hit kinetics under summer and winter conditions. In comparison, E. faecalis was inactivated by two-hit kinetics and only 2.5 logs of inactivation were observed after 4 hours of exposure to winter sunlight. Since human enteric viruses are considerably more resistant to sunlight inactivation than E. coli and moderately more resistant than E. faecalis, marine recreational water quality standards should be based on concentrations of enterococci and not on coliform bacteria. Since the mechanism and rate of inactivation of coliphage and human enteric viruses are similar, coliphages appear to be the best indicator for the presence of human enteric viruses in recreational waters, especially coastal waters where abundant sunshine is available. Linear systems approach to subsurface pollutant transport analysis Liu, Clark C.K., C. Ji, and D. Neupane Comprehensive physically based models of chemical transport in soils consist of two nonlinear partial differential equations. An exact analytical solution for these equations is difficult to derive. A numerical solution, on the other hand, produces numerical dispersion and leads to unsatisfactory modeling results. For nonconservative chemicals in adsorptive soils, physically based modeling becomes even more complicated. Simplified models such as mobility index models have been proposed and used, but they are too simple to provide any in-depth understanding of the transport phenomenon. This study shows that by using a linear systems approach, transport characteristics of field soils can be simply described by an impulse response function. The fate and transport of chemical residues in the soil can then be readily determined by convolution integration. This study also shows that the impulse response function of a soil transport system takes the form of a gamma distribution function. Two multiple regression equations, which relate the two parameters of a gamma distribution function with the soil's basic properties, were derived.
Turf irrigation in Hawaii using R-1 effluent: microbial and chemical Effects
Murakami, Gregory A., and Chittaranjan Ray
Soil: the environmental source of Escherichia coli and Enterococci in Guam's streams Fujioka, R., C. Sian-Denton, M. Borja, J. Castro, and K. Morphew
Conservation zoning for groundwater source protection
Lau, L. Stephen, and John F. Mink This paper presents the hydrological paradigm that optimal groundwater recharge takes place in undisturbed natural forests in Hawaii and discusses aquifer sustainable yields and groundwater quality. The Hawaii land use law, which was the first in the United States to regulate land use on a statewide basis, and its ramifications are also discussed. Finally, the recent (1992) five-year review of the conservation districts is presented from the hydrological perspective. The review not only confirms the necessity of the existing conservation districts but also recommends considerable expansion, especially in certain areas of the sparsely populated neighbor islands that are threatened with urbanization. The current status of the recommended changes is discussed.
Integrating an intermittent aerator in a swine wastewater treatment system
for land-limited conditions Yang, P.Y., and Zhiyu Wang A full-scale swine (300 pigs) waste treatment system--including a solid/liquid
separation unit (3m3) with solids holding tank (1.2 m3)
and a liquid holding tank (20 m3), two anaerobic reactors (10 m3
each) in series, an intermittent aeration unit (20 m3), and a sluge
dewatering bed (17 m2)--was used to investigate the impact of integrating
an intermittent aeration unit on the overall process performance of the swine
waste treatment system. The intermittent aeration unit was used for the treatment
of a combination of raw liquid manure and anaerobically treated concentrated
manure. Four optional ratios of aeration time to nonaeration time of 60:36,
5:1, 4:2, and 3:3 hours were investigated. At a hydraulic retention time of
3.2 days and a ratio of aeration to nonaeration of 3:3 hours, the removal efficiencies
for 5-day biochemical oxygen demand (BOD5), total-nitrogen (T-N),
total suspended solids (TSS), and total-phosphorus (T-P) were 98.0%, 92.4%,
95.6%, and 59.4%, respectively, for the intermittent aeration unit. Effluent
concentrations of BOD5, NO-3-N, NH+4-N,
and TSS were 35+12, 2.6+0.8, 36+28, and 78+13 mg/l,
respectively. The impact of integrating an intermittent aeration unit in the
overall swine waste treatment system, which included solid/liquid separation,
anaerobic treatment, and final sedimentation/polishing units is apparent from
its high treatment efficiency for BOD5 and T-N. Economic evaluation
of the swine waste treatment system integrating an intermittent aeration unit
was conducted based on 300, 1,000, 2,000, 3,000, and 5,000 pigs. It was found
that the utilization of biogas and digesting sluge is essential for the benefit
or the profit of operating this treatment system. Integrating the intermittent
aeration unit in the swine waste treatment system provides reduction of energy
consumption cost and reuse/disposal of treated wastewater without causing deterioration
of environmental quality. The integrated system also provides the possiblity
of developing a fabricated-packaged treatment plant of a central swine waste
processing system for application in land-limited tropical/subtropical areas.
Na4EDTA-assisted sub-/supercritical fluid extraction procedure
for quantitative recovery of polar analytes in soil Guo, Fengmao, Qing X. Li, and Jocelyn P. Alcantara-Licudine Supercritical carbon dioxide (SC-CO2) is effective in extracting
nonpolar and slightly polar chemicals from soils. However, pure SC-CO2
is unsatisfactory for recovering polar chemicals in soils. A simple supercritical
fluid extraction (SFE) procedure was developed to quantitatively recover polar
and nonpolar chemicals from soils. The polar chemicals tested were aromatic
acids and phenols. The nonpolar and slightly polar chemicals used as model compounds
were common pesticides and environmental pollutants such as polycyclic aromatic
hydrocarbons. The procedure required pretreatment of the samples with 15% water
(g/g), 5% (ethylenedinitrilo)-tetraacetic acid tetrasodium salt (Na4EDTA)(g/g),
and 50% methanol (ml/g) prior to extractions using SC-CO2 at 60oC
and 34.5 MPa. Recoveries ranged from 90% to 106% for the aromatic acids using
Na4EDTA-assisted SFE compared with only 7% to 63% recoveries of the
corresponding chemicals when no Na4EDTA was used. The method quantitatively
extracted 2,4-D and its close analogues aged in the soil for 2 to 30 days. The
Na4EDTA-assisted SFE was also adequate for extracting phenolic analytes,
including picric acid and pentacholorophenol, with recoveries from 85 % to 104%.
Na4EDTA is a good enhancer for extraction of the 29 analytes representing
a wide range of polarity from the soil using SC-CO2. The method is
valuable for the analysts of parent pollutants and transformed products, particularly
oxygen-borne metabolites in the environment.
Hawaii rainwater catchment systems development: Draft guidelines Fok, Yu-Si, Leroy F. Heitz, and Henry H. Smith The objective of this paper is to present a draft of Hawaii Rainwater Catchment Systems (RWCS) Development Guidelines for the conference participants and the readers of this paper. The purpose of this paper is (1) to present research results of our investigations as outlined in the USGS Collaborative Research Project (09/01/97 to 08/30/99) to form the basic approach of the RWCS development guidelines, (2) to assess the abilities of RWCS users to comply with the items that have been proposed in 1994 Hawaii House Concurrent Resolution no. 214, and (3) to show the Draft Hawaii Rainwater Catchment Systems Development Guidelines which may be adopted by the public sector to regulate RWCS development and management. The objective of this paper is to present a brief draft of the guidelines for Hawaii rainwater catchment systems (RWCS) development for conference participants and readers of this paper to review and comment on. This paper is divided into four major parts: (1) results of our investigation of this subject, (2) assessment of RWCS users ability to comply with guidelines developed under House Concurrent Resolution No. 214 (Hawaii House of Representatives, 1994), (3) discussion and evaluation, and (4) conclusions.
UV disinfection: To pilot or not to pilot? Moreland, Victor, Audrey Asahina, Tua Unutoa, and Roger Fujioka Honolulu evaluates and compares established wastewater treatment systems with newer technology. The effectiveness of low- and high-intensity ultraviolet lamp technology to disinfect unfiltered secondary effluent is evaluated in this pilot-scale study. One goal was to determine the true UV dose required to disinfect indicator bacteria in unfiltered secondary effluent using a collimated beam unit. Another focus was to correlate the effectiveness of all three UV systems while verifying water quality for each.
Political economy of protecting unique recreational resources: Hanauma Bay,
Hawaii Mak, James, and James E.T. Moncur The impact of tourism growth on the environment has become an increasingly important public issue in travel destinations. We review Honolulu's recent experience in designing management strategies to protect one of its most popular, unique, and endangered natural recreational resources, Hanauma Bay Nature Park. We explain why Honolulu City Council members first adopted nonprice rationing techniques to reduce visits in the park and later added an admission fee only to replace it with a lower and less efficiency-enhancing fee structure. Lawmakers desire (i) a quality environment, (ii) to collect economic rents (i.e., achieve economic efficiency) for the benefit of the general public, and yet must (iii) achieve a political equilibrium. As Honolulu's experience demonstrates, goals (i) and (ii) often conflict with goal (iii), yielding typically a second-best outcome. Efficiency can be attained only if it is also consistent with attaining political equilibrium.
Optimal allocation of ground and surface water in Oahu: Water wars in paradise Moncur, James, Jim Roumasset, and Rodney Smith Despite abundant rainfall and groundwater resources, the State of Hawaii has managed to erect so many barriers to efficient use that serious conflicts have erupted over use rights to water. In what is currently the most prominent battle, environmental and agricultural interests of windward Oahu are pitted against agricultural producers on the leeward side over the allocation of aqueduct water in the Koolau Mountains. To inform this debate, a model of conjunctive use is constructed and optimal allocation of ground, surface, and aqueduct water computed. Optimal use of the aqueduct water is as a substitute for groundwater. This postpones the eventual, expensive use of desalination, thus benefiting future users. By making use right fully transferable and charging current users water's true opportunity cost, both windward and leeward users would be winners.
An on-farm swine waste management system in Hawai‘i Yang, P.Y., and C. Gan A prototype of a swine waste treatment system for a 20- to 25-sow operation
was investigated for its potential for odor control, byproduct utilization,
and treated wastewater reuse. The high solid portion of the swine waste ranging
from 4% to 8% total solids was treated and stabilized by the anaerobic process
with a hydraulic retention time (HRT) of 32 days. The diluted liquid portion
from raw and anaerobically digested swine wastewater was effectively treated
by the aeration and sedimentation units with an HRT of 3 and 4 days, respectively.
The overall removal efficiency of 89% to 95.4% for total chemical oxygen demand
(TCOD), 82.3% to 88.5% for total Kjeldahl nitrogen and 81.2% for total-phosphorus
was achieved. The treated effluent was reused for irrigation of pasture without
any negative impact of odor problems. Also, it meets the requirements of the
wastewater reuse criteria, R-3, issued by the Hawai‘i Department of Health.
The economic analysis was conducted by calculating the net present worth. It
was found that the capital cost is the major cost for the proposed treatment
system. The reuse of biogas as energy and sludge as fertilizer are the key factors
as to whether or not it will turn the treatment system into a profit. More than
830 pigs (or approximately 80 sows) are required to achieve the breakeven point
for the application of the swine waste treatment system. Thus, a profit could
be made with the application of this treatment system to more than 830 pigs
if the comprehensive utilization of methane gas and stabilized sludge could
be realized.
Entrapped mixed microbial cell process for combined secondary and tertiary
wastewater treatment Yang, P.Y., and K. Cao An entrapped-mixed-microbial-cell process was investigated for the simultaneous
removal of carbon and nitrogen in a single bioreactor with influent COD/N ratios
varying from 4 to 15 and with influent alkalinity concentrations of 140 mg/l
and 230 mg/l as CaCO3. The alternated schedules of the intermittent
aeration was operated for two different sizes of carriers (i.e., medium carrier
is 10x10x10 mm3 and large carrier is 20x20x20 mm3). It
was found that the medium carrier achieved higher removal of nitrogen, COD,
and BOD5 at 92%, 95%, and 97%, respectively. This was under the operation
of a hydraulic retention time of 12 hours, 0.5 hour of aeration/ 2 hours of
nonaeration, and a COD/N ratio of 15 in the influent. The influent alkalinity
concentration of 140 and 230 mg/l as CaCO3 has minimum effect on
the removal of carbon and nitrogen. However, the oxidation-reduction potential,
ranging from -100 to 300 mV, provides better nitrogen removal efficiency to
maintain the total nitrogen (NO-3-N, NO-2-N,
and NH+4-nitrogen) at less than 10 mg/l when a COD/N ratio
of 10:15 is maintained in influent. The higher ratio of COD/N in the influent
performs better nitrogen removal efficiency; i.e., COD/N of 15>10>7>4. It is
apparent that the EMMC process is technically feasible for the simultaneous
removal of carbon and nitrogen under the operation of an alternated aeration/nonaeration
schedule in a single bioreactor. Ultimately, it can replace or upgrade the existing
combined secondary and tertiary wastewater treatment plant in one bioreactor
and provide simple maintenance and operation.
RWCS development guidelines: A bridge for private and public sectors' partnership Fok, Yu-Si The number of rainwater catchment system (RWCS) users has increased all over
the world in recent decades. The reasons are many, but the major ones are (1)
the concentration of people in cities of developing countries and (2) the greatly
increasing demand for water for food production in rural areas, especially in
arid and semiarid regions. The population in cities of developing countries
has increased from 773 million in 1950 to 2.6 billion in 1995, a 336% increase
in just 25 years. This increase has caused frequent water shortages, resulting
in the need for more RWCS development. The public sector has become greatly
concerned about RWCS development because the private systems were built without
building permits or without following building codes. When building private
RWCS, individuals need to comply with regulations developed by governmental
agencies to ensure that the public health and safety of all citizens are not
compromised. Hence, there is a definite need for RWCS development guidelines
to bridge the different viewpoints of the private and public sectors. This paper
presents the approach that a set of guidelines would be an important bridge
for the partnership between the two sectors for RWCS development and management.
Rainwater catchment systems development guidelines Fok, Yu-Si Most rainwater catchment systems (RWCS) are developed and managed by private
users. From the public safety standpoint, RWCS are a concern because the construction
of the water supply systems is unregulated since no building code or building
permit is required at present. From the public health standpoint RWCS are often
a big concern because the water quality is not monitored for potable uses. According
to Wilken (1995), the number of people living in urban areas jumped from 737
million in 1950 to 2.6 billion in 1995. The urban share of the total population
increased from 29% to 45% in just 45 years. More than 50% of the developed countries'
populations were already urban by 1950; therefore, the increase in urban populations
in recent decades largely took place in developing countries. The rapidly increasing
population rate has a great impact on the public utilities. A great demand in
such a short time causes frequent water shortages. This becomes a problem because
traditional water supply development requires sufficient time to plan to acquire
water rights and right-of-ways, and to obtain permits and funding. Most immigrants
to cities are poor and are trying to earn a living in the city. The water shortage
problems are just part of their daily struggles. RWCS development is a suitable
solution for them. This paper presents a set of RWCS development guidelines
based on the affordability principle in order to provide a common ground for
the public and private sectors to solve the water shortage problem.
Status of RWCS development and progress of IRCSA. Fok, Yu-Si The development of rainwater catchment systems (RWCS) has been gaining great
momentum worldwide in recent decades. This is partly due to the United Nations
General Assembly's proclamation of 1981-1990 as the International Drinking Water
Supply and Sanitation Decade and partly due to the series of international conferences
on rainwater catchment systems that began in June 1982. To date, eight conferences
have been held at about two-year intervals in different cities of the world
to promote RWCS development. A brief description of the Thailand Jar Project,
an example of a national project that aimed to provide a safe and adequate drinking
water supply for the country's rural residents, is included in this paper. Highlights
of the progress in RWCS development made by the International Rainwater Catchment
Systems Association, which was formed at the fourth conference in August 1989,
are also included.
Near-field mixing of wastewater effluent from the Pali marine outfall, Northern
Taiwan. Liu, Clark C.K., Jing Li, and Huashan Lin The Pali marine outfall, an important element of the Tansui River water pollution
control project in Northern Taiwan, was designed to discharge wastewater at
a rate of 37 m3/s, or about 840 mgd, into Taiwan Strait. To minimize
the potential adverse impact of this discharge on the marine environment requires
a thorough understanding of effluent mixing in receiving water. Generally, the
negative environmental impact would be small if the waste materials in an effluent
plume could be significantly diluted. The magnitude of near-field mixing depends
on both waste effluent characteristics and ambient ocean conditions. Relevant
ocean conditions include ocean current, density stratification, and ocean waves.
The effect of ambient ocean waves on near-field mixing has been ignored by almost
all existing mathematical models. In this study, the popular near-field mixing
model UM was modified to include wave effect. The modified model was then used
to predict effluent mixing in the Pali outfall area. Simulation results show
that the minimum required initial dilution ration of 100 to 1 can be achieved
when the ambient current velocity is 2 m/s or higher. Further, the simulation
results indicate that ambient waves play an important role in near-field mixing.
When the amplitude of ambient ocean waves is 2 m or higher, the Pali outfall
effluent can achieve the required dilution, even in the absence of ocean currents.
A prototype small swine waste treatment system for land limited and tropical
application Yang, P.Y., E. Khan, G. Gan, D. Paquin, and T. Liang. A prototype of a 300-pig waste treatment system was constructed at the animal
research farm of the University of Hawai'i. The system includes a solid/liquid
separation unit (12 m3), and one combined rock bed filter and aquatic
plant reactor (20 m3). Based on the current results of a 240-pig
operation. methane gas production and total solids (TS) reduction are 0.75 m3/m3/day
and 72.7%, respectively, at a loading rate of 3.09 kg TS/m3. The
aeration unit provides a TCOD and NH3-N reduction of 94% and 91%,
respectively. The rock filter achieves a TCOD, NH3-N, and NO3-N
reduction of 32.8%, 26.8%, and 68.4%, respectively. The annual cost for each
of the treatment components is presented. It is very useful for the apllication
of each treatment unit for the various needs of each pig farm.
An on-farm swine waste treatment system for odor control, byproduct recovery
and treated wastewater reuse in Hawaii. Yang P.Y., C. Gan, D.G. Paquin, and T. Liang A prototype of swine waste treatment system for 240- to 240-pig operation was
investigated for its potential for odor control, byproduct utilization, and
treated wastewater reuse. It was found that the high solid portion of the swine
waste rangine from 4% to 8% total solids could be treated and stabilized by
the anaerobic process with a hydrulic retention time (HRT) of 32 days. The diluted
liquid portion from raw and anaerobically digested swine wastewater could be
effectively treated by the aeration and sedimentation units with an HRT of 3
and 4 days, respectively. The overall removal efficiency of 89.0% to 95.4% for
total chemical oxygen demand, 82.3% to 88.5% for total Kjedahl nitrogen, and
81.2% for total phosphorous could be achieved. The treated effluent could be
reused for irrigation of pastures without any odor problems. Also, it meets
the requirements of the wastewater reuse criteria, R-3, issued by the Hawai'i
Department of Health. An economic analysis was conducted by calculating the
net present worth. It was found that the capital cost for equipment is the major
expense item for the proposed treatment system. The reuse of biogas as energy
and sluge as fertilizer was determined to be the key factor in turning the treatment
system into a profit operation. Also, it was found that the farm operation would
require more than 830 pigs for the swine waste treatment system to achieve a
breakeven point. Thus this treatment system could result in a profit by centralizing
the hog operation and by fully utilizing the produced methane gas and digested
sluge.
Conservation zoning for groundwater source protection. Mink, John F., and L. Stephen Lau Conservation zoning in Hawaii dedicates lands for the protection of watersheds
and water sources. The designated lands include forest and vacant areas but
exclude areas for major uses such as urban and agricultural. This has been the
practice on the island of Oahu since the 1920s. The sizable conservation district
(about 40% of the island land) in high-rainfall mountains ensures the recharge
needed for groundwater sources that provide over 99% of the drinking water supply
for Oahu. Is this policy wise, or is it too inflexible and draconian to be applicable
to water source protection for other communities? This paper presents the hydrological
paradigm that optimal groundwater recharge takes place in undisturbed natural
forests in Hawaii and discusses aquifer sustainable yields and groundwater quality.
The Hawaii land use law, which was the first in the United States to regulate
land use on a statewide basis, and its ramifications are also discussed. Finally,
the recent (1992) five-year review of the conservation districts is presented
from the hydrological perspective. The review not only confirms the necessity
of the existing conservation districts but also recommends considerable expansion,
especially in certain areas of the sparsely populated neighbor islands that
are threatened with urbanization. the current status of the recommended changes
is discussed.
Accounting-induced distortion in public enterprise pricing. Moncur, James E.T., and Richard L. Pollock Municipal water utilities commonly aim to set prices at average cost. Because
of various omissions and owing to inflation, unadjusted accounting data understate
the economic costs of fixed assets and thus generate inefficiently low prices
and high consumption rates for the output of these enterprises. We investigate
the nature and extent of undercosting and underpricing for a group of large
urban water utilities in the United States. Economic costs appear to be significantly
greater than the corresponding accounting measures for the cases studied.
Rainwater catchment systems: Development and guidelines. Fok, Yu-Si Rainwater catchment systems (RWCS) have been in use for centuries. However,
since most have been developed by users with private funds, few public sector
decision-makers acknowledge the contribution RWCS have for water conservation
and for water supply by including RWCS construction guidelines in their building
code. Due to the great progress in the environmental protection movement and
because public water supply systems have shown their inability to satisfy the
ever-increasing demands for piped water, the need for RWCS development guidelines
that take these factors into consideration becomes evident. This paper aims
to document existing RWCS guidelines; to report the current progress of RWCS
guideline development in Hawaii; to present problems related to RWCS guideline
development, especially those problems related to the affordability of the RWCS
development in Hawaii; and finally to suggest ways for establishing universal
RWCS development guidelines. Using the guidelines developed for Hawaii as an
illustration, this paper points out the importance of conducting a cost analysis
on items included in RWCS guidelines. To ensure that they are complied with
socially and economically, guidelines must be user-friendly and affordable.
Rainwater catchment systems as an important part for integrated resources
development in arid and semiarid regions. Fok, Yu-Si From the viewpoint of regional resources development, water is a limiting resource
in arid and semiarid regions. Rainwater is a natural renewable resource which
should be harvested and preserved for beneficial uses. Especially in arid and
semiarid regions, rainwater should not be allowed to be lost in the hydrologic
cycle-such as through evaporation, interception, infiltration, and transpiration-without
the benefit of production. This is because if water is available, many other
resources can be developed more fully. This paper shows that rainwater catchment
systems (RWCS) are a vital means for integrated resources development in arid
and semiarid regions, where systems should not only be developed by the public
sector but also be constructed by the private sector. A collective water harvesting
effort conducted on a regional basis should be the water policy in the 21st
century. From the micro-viewpoint, this paper demonstrates that RWCS can be
a solution to the water shortage problem by providing a domestic water supply,
irrigation for garden crops/landscapes, water for firefighting, and water for
agricultural production. The concept of macro-viewpoint in terms of RWCS use
in integrated resource development is introduced and its importance explored.
Water balance, climate change and land-use planning in the Pearl Harbor
basin, Hawai'i. Giambelluca, Thomas W., Mark A. Ridgley, and Michael A. Nullet The Pearl Harbor basin on the tropical oceanic island of Oahu, Hawai'i, exhibits
extreme climate gradients, rapid land-use change, and groundwater use near sustainable
yield. The basin's water usage and groundwater recharge, and hence water yield,
are strongly influenced by the spatial distribution of land use. Current recharge
is expected to drop about one-eighth with the demise of remaining sugarcane
and pineapple. Evidence suggests that lower rainfall and increased evaporation
may well accompany warmer periods in Hawai'i, and water-balance simulations
indicate many scenarios having a significant decrease in available water. Land-use
planners can use such results in tandem with multiobjective optimization models
to generate alternative land-use plans and show trade-offs among objectives.
Development of guidelines for construction of rainwater catchment systems
in Hawaii. Fok, Yu-Si This paper presents the past efforts of the public sector to create guidelines
for RWCS development and, accordingly, provides an assessment of the acceptability
of these guidelines. It also seeks support in obtaining funds to perform a cost
analysis on the guidelines requested by House Concurrent Resolution No. 214,
as included in a master's degree thesis by Todd Boulanger (1994).
Linear systems theory and modeling of river water quality Liu, Clark C.K. The water quality of a polluted river can be improved either by increasing
the river's self-purification ability or by reducing waste loadings the river
receives. Traditional physically based water quality models do not evaluate
separately a receiving river's purification ability and the effect of waste
loadings; thus, they are less than desirable as an analytical tool of water
quality management. An alternative river water quality modeling approach based
on the linear systems theory is explored in this study. In a linear systems
model, a receiving river's self-purification ability is represented completely
by the model's impulse response function, whereas waste loadings the river receives
are represented by the model's input function. The two functions can be evaluated
separately. Furthermore, the water quality condition is the system output and
can be readily calculated by a simple convolution integration of impulse response
function and input function. The linear systems model as a useful water quality
management tool is demonstrated in this paper by applying it to a study of dissolved
oxygen variations in a river which receives both point-source and nonpoint-source
waste loadings.
Sustainable tourism development: Managing Hawaii's 'unique' touristic resource
- Hanauma Bay Mak, James and James E.T. Moncur Journal of Travel Research 33(4):51–57 The impact of tourism growth on the environment is an increasingly important
public issue in travel destinations. However, there has been very little research
focusing on the evaluation of management strategies for the sustainable development
of unique touristic sites. Hawaii has one such unique site in Hanauma Bay Nature
Park. In this case study, we describe and evaluate the recent Honolulu City
and County management plan for Hanauma Bay and suggest several criteria for
the evaluation of management strategies for unique touristic resources. We conclude
that Hanauma Bay is a partial success story of sustainable recreational resource
management. It is argued that efficiency and benefits principles suggest that
visitors to Hanauma Bay be required to pay an admission fee to ration the use
of this scarce recreational resource and to generate revenues to fund park services.
Injected helium technology for environmental near-shore water monitoring Lau, L.S., and A.I. El-Kadi Use of dissolved helium as a water environment-tracer has been documented by
Gupta et al. (Ground Water 32(1), 1994; Hydrological Sciences Journal 93(2),
1994). Helium has many unique attributes that make it attractive for use as
a tracer. They include a low background atmospheric concentration, a low molecular
diffusion constant in water, a moderate solubility in water, and an easy availability
at a low price. This study explored the use of the helium tracer in a shoreline
site in Kona, Hawaii. The site is used for ocean thermal energy conversion and
for aquacultural operations. Waters are disposed of in a ditch near the shoreline.
Continuous monitoring data regarding various chemicals and temperature exist
for a number of wells. The specific objectives are (1) to assess the transport
processes in a trenchwater-groundwater system and (2) to understand the hydrogeology
of the complex system through helium data, extant data, and modeling. Dissolved
helium is introduced with return water discharged into a trench, and water is
sampled from a monitoring well. The model used allows for density-dependent
flow and chemical transport.
Assessment of effects of deep-water, sewage effluent discharge on a near
shore, tropical benthic community, Honolulu, Hawaii. Nelson, Walter G., Julie H. Bailey-Brock, William J. Cooke, and E. Alison Kay The benthic infaunal community near the ocean outfall diffuser discharging
wastewater from the city of Honolulu was sampled from 1986 through 1994. Abundance,
number of species, and the overall species composition of the benthic infaunal
community showed no changes attributable to an effect of effluent discharged
from the diffuser. Both biological and physical (sediment grain size, total
organic carbon, total Kjeldahl nitrogen) parameters showed no indication of
an accumulation of organic matter on the bottom at the stations near the diffuser.
Our studies indicate that there has been little alteration of the benthic community,
even at stations immediately adjacent to the Sand Island Ocean Outfall diffuser.
A survey of selected coral and fish assemblages near the Waianae Ocean Outfall,
Oahu, Hawaii, 1994 Russo, Anthony R. In 1994, coral growth and fish abundance were monitored at three stations located
at and in the vicinity of the Waianae Ocean Outfall. This report summarizes
the results of that survey and comparatively analyzes the data with data collected
in previous sampling years. No significant deleterious effects resulting from
outfall operation and discharge were seen on the biological community at the
stations surveyed.
The role of RWCS in 21st century water management.
Fok, Yu-Si Rainwater catchment systems (RWCS) are age-old water supply systems that will
regain their position in diverse forms to complement centralized public water
systems in the 21st century. Regardless of the level of development, many public
water supply systems have already shown their inability to expand fast enough
to meet the ever-increasing demand for water. As a result, water management
decision makers have made efforts to find complementary ways of providing and
conserving water. RWCS stands out as a practical solution. Users could develop
their own RWCS to become self-sufficient in water, or at least to alleviate
water shortage impacts. This paper explores the role of RWCS in 21st century
water management with viewpoints from the public and private sectors reflecting
social, economic, environmental, and institutional concerns. Also, this paper
proposes the integration of RWCS with other renewable resource collection systems
in designing new sustainable structures for the 21st century.
Organic contamination of groundwater in Hawaii: A learning experience revisited. Lau, L. Stephen, and John F. Mink A 12-year experience of regulatory actions and investigative research of nonpoint-source pesticide contamination of potable aquifers in Hawaii, USA, offers policies and technologies for use by others to forecast or meet similar contingencies. In 1983, Hawaii, the beautiful tropical volcanic islands in the Pacific Ocean, met an unexpected crisis of unprecedented, large-scale contamination of the Pearl Harbor aquifer, the all-important drinking water source for the island of Oahu (Lau et al., 1987; Lau and Mink, 1987). The contamination was caused by volatile organic chemicals -l,2-dibromo-3-chloropropane (DBCP), ethylene dibromide (EDB), and 1,2,3-trichloropropane (TCP) - that had been used with approval as pesticides (nematocides) for pineapple agriculture for up to 35 years. Another use of EDB is as an additive to aviation gasoline. Military records show many major spills. The basalt aquifers, which are highly permeable with a regional hydraulic conductivity value of 500 m/day, consist of numerous thin (3 m), discontinuous, inhomogeneous layers of lithified lava flow. The water table is deep -195-265 m below ground surface at Mililani. Abstract truncated.
Sustainable rural water supply: Rainwater catchment systems Fok, Yu-Si, Kyung H. Yoo, and Todd A. Boulanger Rainwater catchment systems are regaining their reputation as a viable means
of providing a sustainable water supply in rural areas and urban centers. In
the United States, more than 250,000 rainwater catchment systems are scattered
in the rural areas of many states. The number of such systems per state ranges
from 100 in Vermont to 80,000 in Kentucky. This paper presents the recent progress
of rainwater catchment system development. Requests for maintenance and operation
guidelines by state legislatures are positive trends to promote the use of rainwater
catchment systems in rural and urban areas. The prospect of incorporating rainwater
catchment systems in 21st century buildings as part of renewable resources collection
and utilization systems is also presented.
Rainwater harvesting: A practical means for water resources development
and management in arid countries. Fok, Yu-Si, and Show-Chyuan Chu This paper presents examples of recent rainwater catchment system development
in urban and rural areas. It also cites the importance of a national policy
on rainwater harvesting and shows a matrix relating per capita annual average
income with the types of water supply systems that are affordable by water users.
This paper also explains that an ideal situation exists for private ownership
of a rainwater harvesting system. This brings back the tradition of users managing
their own water supply and not relying on the public water supply system. This
is especially important in arid countries. Water is life! This paper also points
out that the trend of 21st century buildings is for their construction to be
in harmony with the environment. Natural renewable resources provided by mother
nature should be beneficially collected and utilized by each building; in other
words, each building should be constructed to serve as collectors and conservers
of water and energy.
An analytical groundwater modeling approach for natural resources utilizing
GIS Oloufa, A.A., A.I. El-Kadi, A.A. Eltahan, and H.U. Malik Successful water resource management requires the availability and synthesis
of data from a multitude of sources. The system should also be capable of retrieving
data related to these aspects in a format suitable for analysis by various simulation
models. The objective is to store the required data pertaining to the various
water and environmental resources in a flexible format that is simple to update,
and to utilize a technology capable of linking the various parameters in an
intuitive visual format. The technology of geographical information systems
(GIS) offers such an approach. This paper discusses the design, development,
and implementation of a GIS for water resources information management and modeling.
Ease of use, portability, and data shareability are some of the major factors
considered in the design of our system. For this pilot project, databases for
soil types, water wells, aquifer classifications, rainfall rates, and streams
are used as the underlying databases. Utilization of the GIS as a shell for
analytical groundwater modeling is also presented.
Simulation of 1,3-dichloropropene in topsoil with pseudo first-order kinetics Lin, Pengzhi, Clark C.K. Liu, Richard E. Green, and Randi Schneider For fast-degraded chemicals such as 1,3-dichloropropene (1,3-D), their long
persistent time in topsoils cannot be explained by the ordinary first-order
kinetics of biodegradation that is commonly used in the simulation of chemical
transport in soils. The Monod kinetics of biodegradation, which is usually defined
as the mathematical relationship between the residual concentration of the growth-limiting
substrate and the specific growth of degraders in laboratory reactors, was found
to be responsible for the phenomenon of "decelerated biodegradation." To take
advantage of both the simplicity of first-order kinetics in transport modeling
and the realistic description of Monod kinetics for a physical situation, a
simplified method was used to represent Monod kinetics with the corresponding
pseudo first-order kinetics. Pseudo first-order constants fitted with Monod
kinetics were later substituted into the transport model. A satisfactory agreement
between field measurement and simulated results using these constants was achieved.
Land-use planning and water resources in Hawaii under climate change. Giambelluca, T.W., M.A. Ridgley, and M. Nullet The Pearl Harbor basin on the tropical oceanic island of O'ahu, Hawai'i, is
characterized by extreme climatic gradients, a fragile hydrolic system, and
rapid land-use change. With all the management problems posed by those attributes,
planners must now also consider the effects upon the regional hydrolic system
due to possible climatic change. This paper describes an ongoing modeling effort
to design and evaluate alternative land-use patterns under present and possible
future climates. First, the paper focuses on the hydrogeological effects of
climate change by estimating such possible effects through the application of
a water-balance simulation model to each of 49 different climate scenarios.
Evaporation is estimated to increase if temperature increases. Water-balance
model runs demonstrate that for an increase of potential evaporation of 10%,
even an increase in rainfall of 10% may still result in a significant decrease
in available water. The problem of incorporating such findings into planning
models is then addressed, with the discussion centering on the applicability
of interactive multiobjective optimization. Reference-based programming techniques,
perhaps utilizing some notions from fuzzy and stochastic programming, are considered
especially suitable.
Assesment of four rainwater catchment designs on cistern water quality Faisst, Eric W., and Roger S. Fujioka This paper reports on an experiment in which rainwater was collected from the
same corrugated metal roof of a given building using for different collection
designs, eah with an identical 55-gallon plastic cistern tank as the catchment
device. The four variations in design were a covered tank with screen device
(Gutter Snipe), a covered tank with screen and foul-flush diverter, a covered
tank with sceen and sand/gravel/charcoal filter, and an uncovered tank as a
control. The drinking water quality of the four cisterns was evaluated by testing
for concentrations of bacteria (total bacteria, total coliform, fecal coliform,
and hydrogen sulfide producing bacteria), conductivity, turbidity, PH, and phosphates.
The results indicated that tank 4 (samd/gravel/charcoal filter) demonstrated
the lowest levels of indicator bacteria, ranging from 0 to 6 fecal coliforms
per 100 ml (average of 1.3 CRU/100 ml); followed by tank 3 (foul flush) witha
range of 0 to 168 CFU/100 ml (average of 17.8 CFU/100 ml); tank 2 (screen only)
with a range of 0 to 388 CFU/100 ml (average of 51 CFU/100 ml); and tank 1 (uncovered)
with a range of 0 to 2.59 x 104 CFU/100 ml (average of 2340 CFU/100
ml). However, concentrations of at least one of the three fecal indicator bacteria
(total coliform, fecal coliform, and hydrogen sulfide producing bacteria) were
often recovered from these waters, indicating that the systems designs were
not able to meet U.S. microbiological drinking-water standards. All four systems
were below the maximum turbidity level of 5 NTU established for individual sources.
These cistern waters were also determined to have very high concentrations of
total bacteria, always exceeding 500/ml, the minimum level at which interference
with the recovery of total coliform bacteria has been reported. Fecal (44.5oC)
and total (33.5oC) coliform results were compared with the hydrogen
sulfide MPN method (room temperature). The hydrogen sulfide test correlated
better with fecal coliform results as compared to talk coliform results after
a 24-hour incubation period.
Guidelines and microbial standards for cistern waters. Fujioka, Roger S. Despite the availability of information on how best to design, build, and maintain
rainwater cistern systems to ensure adequate water quality, few people follow
these guidelines. Studies in Hawaii and elsewhere reveal that most cistern owners
have not heard of foul-flush devices, do not clean their water collection/resevoir
tanks at regular intervals, and do not disinfect their waters. In addition,
many do not use filters. As a result of these practices, most cistern waters
don not meet the U.S. Environmental Protection Agency bacteriological standards
for drinking water. The poor quality of cistern waters in Hawaii is not due
to insufficient education of the owners, to poor sanitary conditions, or to
the use of makeshift materials to construct the cistern systems. Worldwide,
the quality of most cistern waters has not been determined, as such systems
are regarded as private and many countries do not require the monitoring of
cistern water quality. However, available information indicates that most cistern
waters cannot meet microbial standards. Implementation of guidelines for cistern
systems will improve water quality, but waters may never consistently meet EPA
drinking-water standards. Most cistern waters can be determined to be free of
ontamination from human fecal wstes, and the risks associated with water containing
nonhuman sources of indicator bacteria should be less than that of water containing
indicators of human origin. Under these conditions, a realistic microbial standard
for cistern water of 10 fecal coliforms/100 ml is proposed.
Groundwater recharge with Honouliuli wastewater irrigation: Ewa plain, Southern
Oahu, Hawaii. Lau, L. Stephen Groundwater replenishment by irrigation with primary chlorinated effluent from
the Honouliuli Wastewater Treatment Plant was tested in a three-year demonstration
project for the Ewa limestone aquifer, island of Oahu, Hawaii. Among the six
options tested with different combinations of crops (California grass and sugarcane),
irrigation methods, and effluent application rates, the most acceptable was
California grass which was grown in plots (0.5-acre each) surrounded by an earth
berm and border-flood-irrigated intermittently at an average rate of 20 in./wk.
Yield of 1 mgd recharge water required a 14.6-acre plot for this option. For
all options, recharge through 3 feet of vegetated, fairly permeable soil overlying
30 feet of permeable reef limestone rock freshened groundwater chlorides to
245 mg/l, stripped virtually all effluent nitrogen, and inactivated effluent
bacteria. Toxics analyzed (pesticides and heavy metals) were all below action
or detectable levels. The natural system, which acts as a surface living filter
and a subsurface trickling filter, outperformed secondary treatment in improving
the water quality. No adverse environmental effects were identified-no surface
runoff, no insects, and no groundwater contamination. Soil clogging was not
evident. Plots were free of shallow standing water except for a few hours after
effluent application. The mild odor noted only infrequently on site was less
than that at the treatment plant. The biomass produced was of usable quality
and adequate quantity. The simulated recharge water spread in the aquifer several
hundred feet from the site after the irrigation phase of a California grass
growth cycle. The state of Hawaii is presently planning a large-scale water
reclamation facility that will upgrade the Honouliuli primary effluent by this
system to a quality suitable for subsequent reuse.
Hawaii: A tropical paradise with clean water environment Lau, L. Stephen This paper discusses Hawaii in terms of a tropical paradise with a clean water
environment. Water resources include groundwater, coastal waters, and other
waters such as the few natural lakes and large perennial rivers, streams, rainwater
caught by rooftop catchment systems, wastewater effluent (for reuse on land),
and desalted water (using membrane technology). Water regulation and management,
as well as research and graduate education, are discussed. The paper also includes
lists of some outstanding successes and some lessons (learned and in progress)
regarding Hawaii's water resources and water environment.
On the numerical solutions of one-dimensional flow in the unsaturated zone. El-Kadi, Aly I. Analysis and prediction of water flow patterns in the unsaturated zone are
critical to many water resources and environmental problems. Examples of such
problems include infiltration, which is an important part of the hydrologic
cycle encompassing the associated movement and storage of subsurface water.
Soil properties are a major factor in controlling rainwater partition between
infiltration and runoff as well as in controlling moisture movement. Hence,
an accurate estimation of infiltration and the factors affecting it is required
to facilitate a reliable prediction of runoff and subsurface moisture distribution.
Another example is related to agricultural management in which unsaturated water
flow needs to be considered in decision making regarding irrigation. Finally,
chemical transport in the subsurface environment is greatly influenced, under
certain conditions, by flow in the unsaturated zone. Contamination may be caused
by leakage from sanitary landfills or by recharge of sewage water under unsaturated
flow conditions. Irrigation and rainwater dissolve and carry fertilizers, pesticides,
and other chemicals under unsaturated conditions also. In most cases, understanding
chemical transport and transformations in the unsaturated zone is essential
for assessing the actual or potential contamination of groundwater aquifers.
Flow in the unsaturated zone is usually simulated by solving the Richards equation,
which is derived by combining the mass conservation equation and Darcy's law.
Recent studies have reported problems in solving such an equation within a numerical
framework. This paper reviews the theory and various conventional numerical
solutions pertinent to the problem. It also covers recent advances in numerical
techniques that are mostly aimed at improving the efficiency of the solutions
by optimizing the size of the spatial and temporal increments. Most of the attempts
are related, in general, to equation transformation, solution iteration, and
interblock parameter estimation. However, there is still room for improvement,
because in some cases accuracy may require the use of small increments, on the
order of a few centimeters and seconds for the spatial and temporal increments,
respectfully. Such a need is critical because of the burden involved in model
applications for large-scale, multidimensional problems. Although only one-dimensional
problems are addressed here, many of the issues involved can be readily extended
to multidimensional cases.
Ground-water tracing with injected helium. Gupta, S.K., L. Stephen Lau, and Philip S. Moravcik Helium has several characteristics that make it attractive for use as a tracer
in hydrological studies. Two types of experiments were conducted to investigate
applicability of helium as a tracer of groundwater movement. The experiments
included studies using laboratory sand and soil columns and field groundwater
tracing in a basaltic aquifer. A water helium analyzer comprised of a thin quartz
glass membrane and diode ion pump (making use of the preferential permeation
of helium through the quartz glass into an evacuated space) was developed and
used for the experiments. Study results demonstrated that breakthrough curves
of specific conductance and helium were similar under saturated conditions.
In the unsaturated sand/soil columns, breakthrough curves of helium were retarded
relative to specific conductance, reducing the usefulness of helium as a tracer.
Use of helium as a hydrological tracer. Gupta, Sushil K., Philip S. Moravcik, and L. Stephen Lau Helium has several characteristics which make it attractive for use as a tracer
in hydrological studies. These include its inert nature, relatively high solubility
in water (~1%), low molecular diffusion in water, ready availability in commercial
quantities, nontoxic nature, and low background atmospheric concentration. The
use of helium as a tracer of water movement has become possible through the
development of an instrument which takes advantage of the fact that at room
temperature helium diffuses through a quartz glass membrane at a rate of three
to four orders of magnitude greater than any other gas. This paper describes
(1) a set of experiments undertaken to compare breakthrough of helium with common
salt (NaCl) tracer through laboratory sand columns; (2) a set of groundwater
tracing experiments conducted in a basaltic aquifer in central O'ahu, Hawai'i;
and (3) two laboratory experiments undertaken to evaluate the applicability
of helium instrumentation for the tracing of submerged plumes in open water
conditions. The test results demonstrate that helium behaves as a conservative
tracer during saturated flow through porous media. During unsaturated flow,
exchange of helium with air entrained in the porous media reduces its usefulness.
During submerged flow of a labeled plume, helium behaves like fluorescein in
a relatively tranquil laboratory tank environment for hours but is gradually
lost through the air-water interface, thus limiting the usefulness of helium
in shallow plume tracing studies to short duration experiments.
Stochastic analysis of the relationships between saturated hydraulic conductivity
variance and solute dispersion in heterogeneous soils Azimi-Zonooz, Ali, and Clark C.K. Liu The effect of three-dimensional heterogeneity of saturated hydraulic conductivity
on the vertical transport of solutes in soils is examined by means of controlled
numerical experiments. Saturated hydraulic conductivity, an important transport
parameter that controls the dispersion of pollutants in heterogeneous soils,
is assumed to be composed of a homogeneous mean value and a perturbation caused
by the vertical variability of soil properties, producing a stochastic process
in the mean flow direction. The spatial heterogeneity of porous soils is characterized
by the variance and correlation scale of the saturated hydraulic conductivity
in the transport domain. Numerical experiments are carried out to evaluate the
extent of contaminant dispersion in Hawaiian Oxic soils when uncertainty exists
as a result of the spatial heterogeneity of saturated hydraulic conductivity.
Statistical analysis of the saturated hydraulic conductivity measurements on
undisturbed soil cores from two locations in Hawaiian Oxic soils indicated two
different soils with the same mean and different variances. The partial differential
equations describing three-dimensional transient flow and solute transport in
soils with a random conductivity field were solved to evaluate the effect of
these two variance levels on the transport of a contaminant plume originating
from the surface. The significance of the variance on the spatial and temporal
distribution of tracer concentrations is demonstrated using solute breakthrough
curves at various depths in the soil profile. The longitudinal macrodispersivity
resulting from tracer spreading in the heterogeneous soils with a finite local
dispersivity is also analyzed. The analysis shows a similar solute dispersion
behavior for the two variances. However, there is an overall reduction in the
dispersion of solutes resulting from a uniform velocity field with the same
mean. Macrodispersivity values in heterogeneous soils are proportional to the
variance at smaller travel distances but converge to the same value at larger
travel distances.
Artificial recharge of ground water for all purposes? Lau, L. Stephen Along a dry, hot coast on the island of Oahu, Hawaii, several needs-water demand
for a new city, salinization control for a limestone aquifer, and management
of wastewater effluent from an ocean outfall discharge-can be met through artificial
recharge of groundwater by irrigation with a primary effluent. Among the six
options tested in a three-year demonstration project with different combinations
of crops (California grass and sugarcane), irrigation methods, and effluent
application rates, the most acceptable was California grass grown in 0.2-ha
plots bordered by an earth berm and flood-irrigated intermittently at an average
rate of 508 mm/wk. A yield of 0.044 m3/s recharge water required
5.9 ha of land for this option; an even higher yield was possible with a minor
change in percolate quality. For all options, recharge through 0.9 m of vegetated,
fairly permeable soil overlying 9.1 m of permeable reef limestone rock freshened
groundwater chlorides to 245 mg/l, stripped virtually all of the effluent nitrogen,
and inactivated effluent bacteria. Toxics analyzed (pesticide and heavy metals)
were all below maximum contaminant levels. The natural system, which acts as
a surface living filter and a subsurface trickling filter, outperformed the
secondary treatment system in improving the water quality. No adverse environmental
effects-surface runoff, insect infestation, and groundwater contamination-were
identified. Soil clogging was not evident. Plots were free of standing water
a few hours after effluent application. The mild odor noted only infrequently
on site was less than that at the Honouliuli Wastewater Treatment Plant. The
biomass produced was of usable quality and adequate quantity. The simulated
plume by the recharge water spread in the aquifer several hundred feet from
the site after the irrigation phase of a California grass growth cycle. This
paper summarizes the technical results on which the planning of a large-scale
facility can be based and addresses the institutional difficulties and land-use
economics, both of which are immense obstacles yet to be overcome.
Use of a geographic information system in site-specific ground-water modeling El-Kadi, A.I., A.A. Oloufa, A.A. Eltahan, and H.U. Malik Groundwater modeling is hindered, in general, by the lack of adequate information
about the groundwater system and hence the need for an interactive and efficient
system for data preparation and results analysis. Such a lack of information
usually necessitates by the use of a tedious iterative methodology within a
sensitive analysis scheme. This study facilitates modeling efforts by using
the data-handling and graphical capabilities of a geographic information system
(GIS) in site-specific, numerical modeling of groundwater resources. Data for
the island of Oahu, Hawaii, are given to illustrate the approach. The modeling
procedure is integrated with the GIS as an item in the main menu. A USGS model,
known as MOC, is linked into the system and applied to a case study to illustrate
the procedure. The linkage is generic in nature and can be extended to other
models as well. The availability of a programming language in the GIS package
facilitates pre- and post-processing efforts within custom-made dialogue boxes
and pull-down menus. On-line help screens for modeling as well as data handling
can also be designed.
Wellhead protection strategy for small aquifers: A study of Hawaii. Lau, L. Stephen, Delwyn S. Oki, and John F. Mink. Small aquifers, especially those of high permeability and with well-defined
boundaries, lend themselves to alternative approaches to wellhead and groundwater
protection. This type of aquifer is common in Hawaii, and many occur elsewhere.
Development of a wellhead protection strategy for Hawaii is technically difficult
because of the wide range of aquifer types and groundwater extraction units.
Three protection approaches are currently being considered for Hawaii. The first
approach involves the delineation of wellhead protection areas around individual
extraction units. This is the approach originally envisioned by the U.S. Environmental
Protection Agency in its guidelines for delineation of wellhead protection areas.
We have identified appropriate delineation methods for the principal extraction
units in Hawaii. The second approach involves delineation of aquifer protection
areas, which are based on aquifer boundaries. The aquifer protection area approach
is conceptually superior to the wellhead protection area approach by virtue
of its comprehensiveness since the entire aquifer is protected, rather than
just isolated areas surrounding the wellheads. The third is a time-phased approach
that involves the initial delineation of wellhead protection areas followed
by an aquifer protection area; that is, delineate wellhead protection areas
during the early stage of groundwater exploitation, and then switch to an aquifer
protection area at a later stage of exploitation near the sustainable yield
of the aquifer. These approaches provide a choice, depending on the degree of
protection desired and the extent of groundwater development in the aquifer.
Modeling atoll groundwater systems. Peterson, Frank L., and Stephen B. Gingerich With the application of high-speed computer modeling, we have begun to understand
the details of hydrodynamic processes within atoll groundwater systems. One
model used to simulate variable-density groundwater systems within atolls is
SUTRA. The use of this model to evaluate several aspects of fresh groundwater
lens dynamics and development on atoll islands is described. Two different atoll
models were simulated. The first uses a generic atoll island with hydrogeologic
parameters that are a composite of several typical atoll islands in the Pacific
Basin to evaluate controls on the size and dynamics of the freshwater lens.
The second models development and sustainable yield under various recharge conditions
for Roi-Namur Island in Kwajalein Atoll, Republic of the Marshall Islands.
Groundwater modeling in Hawaii: A historical perspective. Lau, L. Stephen, and John F. Mink Water supply has been a dominating feature in the evolution of the Hawaii economy since the first settlement of the islands more than a millennium ago. The early Hawaiians relied on water from streams, springs, and shallow excavations to irrigate crops, taro in particular. Water use was regulated by the Hawaiian chiefs and their land managers according to strict rules. The source and delivery systems were so well designed that they served the expanding economy for a century after the opening of the archipelago to the western world by Captain James Cook in 1778. The prediscovery Hawaii economy was highly organized and successful. When Cook arrived the population of the islands was about 300,000, but a century later it had declined to about 60,000 as a result of devastation caused by western diseases and the breakdown of a unifying culture. The demand for water increased to meet the needs of new agricultural initiatives, especially sugarcane, exceeding the supply available from the intricate Hawaiian distribution network. Collection works and transmission systems were constructed by western entrepreneurs. By 1910 virtually every major surface water resource had been seized for plantation agriculture. Still, not enough water was available to satisfy the thirst of the arid lands planted in sugarcane. The greatest impetus to the advancing agricultural economy came with the discovery of artesian groundwater in the Ewa Plain in southwestern Oahu in 1879. Widespread drilling followed, proving the existence of vast groundwater resources. The experience was quickly repeated on all of the major islands. The arid leeward plains of each island, blessed with a bounty of sunshine, became the premier agri¬cultural lands through irrigation with groundwater. Honolulu, served by an unreliable surface water supply for all of the 19th century, prospered and grew after voluminous artesian groundwater resources were discovered beneath the coastal plain. The city became the uncontested urban and commercial center of the island chain. Groundwater became the first choice for municipal drinking water, and as the public appreciated its purity and reliability it also worried about its sustainability. A severe drought in 1926 magnified the concern, leading to the creation of the City and County of Honolulu Board of Water Supply. Basic investigations by the U.S. Geo¬logical Survey, which had started a few years earlier, were expanded. The adequacy of the groundwater resources of southern Oahu was severely tested in World War II when a large military population was grafted on the existing civilian and agricultural economy. Then in 1959 Hawaii became a state, setting off a wave of economic activity which concurrently expanded demand for water. By the 1970s the combined agricultural, military, and civil economy water demands in southern Oahu were rapidly approaching sustainability of the aquifers. Elsewhere in the islands economic expansion also strained water source and distribution systems. The adequacy of the groundwater supply persisted as an unusually widespread concern among the public. Finally, after nearly a decade of legislative attempts, a State Water Code reg¬ulating all water development became law in 1987.
Hydrogeology of the Marshall Islands Peterson, F.L. The Republic of the Marshall Islands consists of 33 atolls containing some 1,136 separate islands in the west central Pacific. The atolls are aligned in a NW-SE direction and extend over a distance of nearly 1,100 km. They form two roughly parallel chains, the eastern Ratak (sunrise) group and the western Ralik (sunset) group. The indigenous people of the Marshall Islands are Micronesians. The first European contact was by Spanish explorer Alvaro Saavedra in 1529. However, the islands' general lack of wealth and resources did not encourage exploitation until 1885, when Germany declared the Marshall Islands a protectorate. In 1914, Japan took control of the Marshall Islands and after 1919 administered them under a League of Nations mandate. During World War II, U.S. forces occupied the Marshall Islands after heavy fighting on Kwajalein and Enewetak, and in 1947 the Marshall Islands became a U.S. trust territory. Finally, in 1986, under a compact of free association, the Republic of the Marshall Islands became fully self-governing and took control of all its internal and foreign affairs. Today the principal economic activities are still subsistence farming and fishing, with increasing effort being di¬rected toward development of a tourist industry. Although the Republic encompasses nearly 500,000 km2 of ocean, the total ex¬posed land area is only about 176 km2 (Mink, 1986). Individual atoll islands are seldom larger than a few square kilometers and average only a few meters in elevation. Owing to their very small size, the lack of freshwater, and the danger of overtopping by storm waves, few of the islands are inhabited. The majority of the population lives on four major atolls: Majuro, the capital; Kwajalein, a center of U.S. defense activity; Jaluit; and Arno. The only public water systems in the Marshall Islands exist on several large islands in these atolls. Elsewhere, individual households obtain water from rainfall catchments and shallow dug wells (Mink, 1986). Most of the hydrogeologic information that serves as the basis for this chapter, therefore, comes from investigations conducted on the major atolls. In addition, a considerable body of information, especially geologic information, is from investigations conducted on Bikini and Enewetak Atolls prior to and after nuclear weapons testing during the 1940s and 1950s (Arnow, 1954; Emery et al., 1954; Ladd and Schlanger, 1960; Ristvet et al., 1978; Schlanger, 1963; Tracey and Ladd, 1974) [see also Chaps. 21, 22].
Modelling chemical transport in topsoil with a gamma distribution function. Liu, Clark C.K., Pengzhi Lin, and Amalia Firman. In applying the linear systems theory to the mathematical simulation of chemical
transport in topsoil, the impulse response function is used to describe the
overall effects of hydrodynamic and kinetic mechanisms of the system. The general
nature of the impulse response function of a soil transport system can be represented
by a gamma distribution function. The multiple regression equations derived
in this study can be used to correlate parameters of a gamma distribution function
with basic soil and chemical properties. Techniques developed in this study
are most suitable for assessing spatial variation of groundwater contamination
potential in a large area.
Water pricing and cost data: Getting the right numbers. Moncur, James E.T., and Yu-Si Fok. The data presented indicate that a substantial increase in water rates is often
justified by real economic costs that are often partially hidden by standard
accounting practice. Such a rate hike would provide each individual water consumer
with a continuing and pervasive incentive to adjust his water use. The resulting
conservation would stretch conventional sources of supply and forestall for
many years the eventual necessity of developing desalination or other truly
expensive sources.
Tubeworms (Serpulidae, Polychaete) collected from sewage outfalls, coral
reefs and deep waters off the Hawaiian islands, including a new Hydroides species. Bailey-Brock, Julie H.. Quantitative benthic samples collected near sewage outfalls off Oahu contained
two species of small, fragile serpulid tubeworms previously unknown from Hawaiian
waters. One is a new species of Hydroides without an opercular funnel, the other
is Josephella marenzelleri, a broadly distributed but easily overlooked serpulid.
Retrieval of these species is attributed to the use of a van Veen grab and elutriation
and sieving to separate the polychaetes from the sediment. Another unrecorded
small serpulid species, Rhodopsis pusilla, was found growing on a hard
foliaceous sponge, in a cave, on a shallow reef off the Kona coast of Hawaii.
Lava rocks collected with a submersible off southeast Oahu (330 m depth) have
yielded another little known serpulid species, Filogranula gracilis.
Soil: The environmental source of Escherichia coli and Enterococci in Hawaii's
streams. Hardina, C.M., and R.S. Fujioka The concentration and sources of Escherichia coli and enterococci in a typical
stream in Hawaii were determined. The concentrations of these two sanitary indicator
bacteria in Manoa Stream consistently exceeded the new U.S. Environmental Protection
Agency recreational water standard in freshwater of 126 E. coli/100 ml
or 33 enterococci/100 ml. Escherichia coli but not enterococci was shown
to multiply in stream water samples. Soil samples obtained near the stream bank,
10 m from the stream bank, as well as from a grassy area on the university campus,
were determined to be sources of both E. coli and enterococci. These
indicator bacteria were recovered from the surface of the soil as well as from
soil samples at depths down to 36 cm. Soil is considered the most likely source
for the high concentrations of indicator bacteria naturally present in the freshwater
streams of Hawaii.
The marine Tubificidae (Oligochaeta) of Hawaii Erasmus, Christer, and Dale Davis The taxonomy and biogeography of the marine Tubificidae of the Hawaiian islands
are studied for the first time. Twenty-three species are reported from largely
subtidal habitats at the islands of Oahu and Maui. Eleven species are new to
science: Bathydrilus exilis, Phallodrilus ampullarius, P. aquilinus, P. distinctus,
Coralliodrilus aequalis, Inanidrilus dutchae, Olavius parapellucidus, O. (Coralliodriloides)
strigosus, O. (C.) mokapuensis, Limnodriloides hawaiiensis, and Tubificoides
pulvereus. Taxonomic notes are given for most of the other species. At least
four of the species recorded from Hawaii have a more or less circumtropical
distribution, whereas six others appear to be members of the Indo-West Pacific
fauna. Three of the Hawaiian species were previously known only from the Caribbean
area, indicating that they may be present in the East Pacific as well.
Hawaii. In Ground Water in the Pacific Region. Natural Resources/Water Series
No. 12 Lau, L.S A description of the major Hawaiian islands is presented. Conditions of groundwater
occurrence, groundwater resources, and groundwater development are discussed.
Urban storm water runoff in Hawaii Young, Reginald H.F. Urban storm water pollution in Hawaii has been the subject of serious study
for only a very few years. The major impetus for such study has been the need
to determine the impact of stormwater or streamflows on coastal water quality.
Early studies conducted by the Water Resources Research Center in Hawaii are
of limited utility, in large part because of the sparseness of accompanying
flow data. These attempts include stream surveys and collection and analysis
of street sweepings. More recently published studies include stream surveys
where pollutant loading rates have been determined, street sweepings where contaminant
loads per length of curbing have been calculated, and direct monitoring in storm
sewers. Data to date indicate contaminant hazards exist for receiving waters
due to suspended solids, heavy metals, and possibly bacterial pathogens. Further
work is necessary to refine loading rates and contaminant levels, especially
as related to land-use pathogens.
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