Technical Reports 131-192 (1980-1993):

From 1967 until around 1993 WRRC published many reports on completed projects in-house. These “Technical Reports” contain a wealth of information on water issues, problems, and research, and are all available in PDF format at the University of Hawaii’s ScholarSpace institutional repository. Click on the report titles to view the abstracts.

SEARCH Technical Reports 131-192 (1980-1993) ARCHIVE

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Technical Report No. 131
LEACHATE QUALITY FROM LYSIMETERS TREATING DOMESTIC SEWAGE

by Gary T. Tasato and Gordon L. Dugan
April 1980

ABSTRACT
A study was undertaken to determine the treatability of raw domestic wastes using waste water treatment lysimeters. A pilot treatment unit was constructed that included four waste water treatment lysimeters, each utilizing a different Hawaiian soil. The soils included two silty clays of the Wahiawa and Lahaina series, a silty loam of the Tantalus series, and a beach sand of the Jaucas series. The use of graded rocks or gravel was incorporated in all of the soil series with the exception of the Wahiawa series. The Wahiawa and Lahaina soil lysimeters employed a top surface application scheme while the Tantalus and Jaucas lysimeters utilized a lateral low scheme. Two residential cottages served as the domestic waste water source and produced flows ranging from 3.15 to 5.04 x 10 6 m3/s (72-115 gpd). In general, the Tantalus and Jaucas series attained relatively higher removal efficiencies than the Wahiawa and Lahaina series. However, in all of the soil series, only moderate constituent removals were observed particularly for dissolved solids, organics, ammonia nitrogen, and bacteria. The only constituents which showed high removals were suspended solids and phosphorus. The primary factor for the low overall removals was probably overloading of the lysimeters inasmuch as both the hydraulic and constituent loadings (especially organics, solids, nitrogen, and bacteria) proved to be excessive. Soil clogging was also evident to some extent in all of the soil series.


Technical Report No. 132
BENTHIC ECOSYSTEM AND FISH POPULATION OFF THE MOKAPU OUTFALL: A SECOND POST INSTALLATION ECOLOGICAL STUDY

by Anthony R. Russo, Steven J. Dollar, E. Alison Kay
May 1980

ABSTRACT
An ecological study of the benthic and fish populations at Mokapu, 0’ahu, Hawaii was completed in the summer of 1979. This is the second post-installation study of the Mokapu Outfall area since the commencement of effluent discharge in December 1977. An initial baseline survey was completed in 1975 (Russo et al. 1977, 1979). Data were obtained from five stations between Mokapu Point on the northeastern tip of Oahu to Alala Point approximately 6 034 m (3.75 mites) south, at depths of 6 to 24 m (20-80 ft) in all surveys. Results show little or no effect from the operation of the outfall on the benthic and fish communities two years after commencement of discharge. There are no significant differences in abundance, diversity or composition of fishes from 1975 to 1979 except over the outfall site where fish abundance increased significantly especially over the diffuser where the snapper Lutjanus kasmira was counted in large numbers (>500). The relative abundance of herbivorous fishes (acanthurids) increased near the outfall. This may be commensurate with an increased coverage of a fine microalgal mat and an increase in the biomass of Lyngbya, a blue-green alga near the outfall site. The biomass of dominant macroalgae did not significantly change at any of the five areas surveyed. Between the 1975, 1978, and present (1979) studies, there are some differences in coral cover which are attributed to patchy substrata distribution rather than stress from the sewer outfall. In comparison with the samples of 1975 and 1978, the 1979 transect D samples and that from the diffuser show a lower, overall abundance in micromolluscan assemblages than was recorded in either 1975 or 1978, and that Tricolia, Vitricithna, Rissoina miltozona., and Bittium increased in relative proportions at the 18 to 16 m (60-80 ft) depth levels and at the diffuser. The differences reflect increasing numbers of micromollusks more usually associated with depths of less than 15 m (50 ft) at greater depths and of species associated with frondose algae and substrata. This trend was noted in 1978 and is apparent again in 1979. Large differences canons some of the 1979 samples and between the 1979 and other year samples reflect the patchiness of the substratum, and cannot be attributed to effects of the sewer outfall.


Technical Report No. 133
BAYES-MARKOV ANALYSIS FOR RAIN-CATCHMENT CISTERNS

by Yu-Si Fok, Ronald H.L. Fong, Jack Hung, Edwin T. Murabayashi, Andrew Lo
March 1980

ABSTRACT
In many parts of the world, public water-supply systems have shown signs of an inability to adequately service increasing demand. As a result, water shortages have occurred and moratoriums on new development areas have been imposed. And because of recurrent droughts and the rapid acceleration of urban development in recent years, the rain catchment system and its cost effectiveness are now regaining the attention of researchers and planners as a “new” and important alternative water supply. Rainfall, catchment area, storage capacity of the cistern, and water demand are the four main elements considered in the design, operation and management of a cistern system. Expected weekly rainfall is the main uncontrollable element of concern to the cistern owner; therefore to meet this problem, expected weekly rainfall probabilities were first simulated by the Bayesian analysis. Then the sequential property contained in the 25-yr rainfall record was utilized to generate the likelihood probability function by using the lag 1 Markov sequential analysis. The Bayes-Markov analysis was subsequently applied to obtain the weekly rainfall probabilities. As a result of these analyses, the Bayes-Markov probabilistic approach for weekly rainfall simulation has shown its usefulness. Design and operational methodologies are also presented in the report.


Technical Report No. 134
SURVIVAL, DISSEMINATION, AND PUBLIC HEALTH SIGNIFICANCE OF HUMAN ENTERIC VIRUSES IN OCEAN WATERS OFF O’AHU: VIABILITY AND DIE-OFF; ROLE AND EFFECTS OF ANTIVIRAL AGENT(S)

Philip C. Loh, L. Stephen Lau, Roger S. Fujioka
May 1980

ABSTRACT
The discharge of domestic sewage into the ocean waters off Oahu is a common practice. Since infectious enteric human viruses have been determined to be present in all sewages, viruses are also being discharged into the ocean environment. This study was undertaken to determine the fate, dissemination, and public health significance of sewage-borne viruses after they enter the ocean environment. Using an experimental, portable virus concentrator, indicator bacteria as well as human enteric viruses were consistently recovered from water samples taken from the surface sewage plume, the result of sewage discharge from the original ocean outfall pipe extending 129.8 m into Malama Bay at a depth of 12.2 m. Recovery of sewage-borne bacteria and viruses decreased as the distance from the plume increased. However, viruses were recovered from a station as far away as 3 218 m east of the plume and within the vicinity of Ala Moana Beach. Significantly, viruses were occasionally recovered in the absence or negligible concentrations of coliform bacteria, indicating that the standard coliform test for water quality may be inadequate as an assessment for the presence of viruses. When the old sewage outfall pipe into Malama Bay was diverted to the new outfall pipe which extends approximately 2 743 m from shore (exclusive of a 914 m long, multi-porthole diffuser) at a depth of 73.2 m, no surface plume was observed and viruses were only sporadically recovered from ocean waters above the discharge pipes (zone of mixing). Viruses were recovered from ocean waters near other ocean sewage outfalls, such as in Pearl Harbor Kaneohe Bay, and Kailua Bay, as well as from boat marinas and a stream emptying into the ocean. Other studies showed that human enteric viruses can be expected to survive for 24 hr in the marine environment before they are actively destroyed. Moreover, evidence was obtained that microorganisms naturally present in all the marine waters off Oahu are responsible for the inactivation of human enteric viruses.


Technical Report No. 135
POST-SECONDARY TREATMENT OF EFFLUENT FOR DRIP IRRIGATION:JULY 1977 TO MARCH 1980, PHASE II-B

L.Stephen Lau, Reginald H.F. Young, George P. Young
1981

ABSTRACT
The freshwater aquifer in the Pearl Harbor area on Oahu, Hawai’i is the most important water resource of the island and constitutes a large proportion of its freshwater supply. The aquifer has a freshwater lens up to 304.8 m (1000 ft) thick, floating on top of a saline water zone. Mechanisms of groundwater movement are extremely complex because the upper boundary is confined near the coast and phreatic inland, while the lower boundary is nowhere confined. In this study, regional groundwater movement due to various pumping schemes is mathematically simulated by a set of partial differential equations. These equations are then solved numerically with a finite difference approximation. The location of the freshwater and salt-water interface, which constitutes the lower boundary of the system model, was estimated by Hubbert’s formula. Consideration was also given to features concerning geohydrologic boundaries of the Pearl Harbor aquifer. It was concluded that a mathematical model can be used as a tool in the management of groundwater development in a thick Ghyben-Herzberg aquifer. Improvement of system simulation may be achieved by adding a mass transport element to study hydrodynamic dispersion within a transition zone where fluid density changes gradually.


Technical Report No. 136
RAINFALL CELL SIZE FROM RIT CURVE ANALYSIS

Charles M. Fullerton, S.K. Wilson, Arne Austring

June 1980

ABSTRACT
A small and closely-spaced network of three to seven rapid response (4-s) rainfall intensity gages has been used to measure intense, short duration rain showers on the windward (eastern) coast of Hawai’i island. During a one year, intensive monitoring period, 54 events were recorded with rainfall intensities greater than 95 mm/hr on at least one gage. Four of these events had peak rainfall rates greater than 250 mm/hr. The 54 events were analyzed in an attempt to derive some properties characteristic of individual high intensity rainfall-producing “cells”. A total of 75 cells, involving 397 separate gage measurements, here extracted from the 54 events by applying an 11-point running mean, averaging technique. The cell data were studied by sorting the rainfall intensity-time plots into curves of symmetrical shape (35.5%), and those exhibiting a positive (43%) or a negative (21.5%) skew. Normalized mean curves then were constructed for each of these three types. Ten cases appeared to involve multiple, overlapping cells, including two cases of long duration thunderstorm rainfall. These ten events were excluded from the results listed below. The average of the 65 single cell cases produced about 5 mm of rain in about 5.5 min, with an average maximum rainfall rate of about 110 mm/hr. The ground rainfall pattern moved across the network with an average speed of about 6.5 m/s. If the cell is assumed to be circular across a plane parallel with the ground, these results imply a mean cell diameter of about 2 km and an average cross-sectional cell area of about 3.2 kM2.


Technical Report No. 137
CONTACT CHAMBER AERATION EFFECTS ON EFFLUENT DISINFECTION

Stanford M. lwamoto, Michael J. Chun, Reginald H.F. Young, Gordon L. Dugan

March 1981

ABSTRACT
The most common method of disinfecting waste water effluent is by chlorination which destroys pathogenic microorganisms in the waste water stream. A field study conducted at the Wahiawa Wastewater Treatment Plant on the island of 0’ahu, Hawaii was established to determine the effect of aeration on disinfection efficiency in the chlorine contact chamber. A range of chlorine dosages was applied to the waste water entering the contact chamber for aeration rates of 0, 2.36 X 10-3, and 4.72 X 10-3 std. m3/s (0, 5, and 10 std. cfm) of air. The chlorine demand and chlorine requirement of the waste water was then determined by measuring the chlorine residual and fecal coliform concentration in the effluent leaving the chlorine contact chamber. The addition of aeration into the chlorine contact chamber enhanced the disinfection efficiency of chlorine, while its effect on chlorine residual loss in the contact chamber was not readily apparent; however, a greater drop in the chlorine residual was observed for higher chlorine dosages during periods of aeration, in comparison to nonaerated conditions.


Technical Report No. 138
WATER QUALITY SIMULATION OF WAHIAWA RESERVOIR O’AHU, HAWAII

Stephen F. Moore, G. Stephen Lowry, George P. Young, Reginald H.F. Young

September 1981

ABSTRACT
Wahiawa Reservoir is a small multi-use facility located on the central plain of Oahu, Hawaii. The goal of this study was to develop and apply a computer-simulation model of water quantity and quality in Wahiawa Reservoir. The model was used to evaluate alternate water quality management strategies. The model represents the reservoir as a dynamic, one-dimensional (vertical) system. Primary emphasis is placed on representing vertical and temporal changes in water level, water temperature and dissolved oxygen. A unique feature of the model is the inclusion of the effort of artificial aeration. Model calibration was accomplished by obtaining statistically acceptable comparisons between simulated and observed water quality values over a .1-yr interval. Model verification results demonstrated a low predictive accuracy for the model as calibrated. However, the general response behavior of the reservoir is well represented by the model. Examples of using the model to predict effects of alternate management strategies showed that anaerobic conditions depend on oxygen demanding sediments and high algal productivity of surface waters. Artificial aeration appeared to be the most effective water quality management strategy.


Technical Report No. 139
NUMERICAL SIMULATION OF A THICK FRESH WATER LENS: PEARL HARBOR GROUNDWATER MODEL

Clark Liu, L. Stephen Lau, John F. Mink,
September 1981

ABSTRACT
The freshwater aquifer in the Pearl Harbor area on Oahu, Hawai’i is the most important water resource of the island and constitutes a large proportion of its freshwater supply. The aquifer has a freshwater lens up to 304.8 m (1000 ft) thick, floating on top of a saline water zone. Mechanisms of groundwater movement are extremely complex because the upper boundary is confined near the coast and phreatic inland, while the lower boundary is nowhere confined. In this study, regional groundwater movement due to various pumping schemes is mathematically simulated by a set of partial differential equations. These equations are then solved numerically with a finite difference approximation. The location of the freshwater and salt-water interface, which constitutes the lower boundary of the system model, was estimated by Hubbert’s formula. Consideration was also given to features concerning geohydrologic boundaries of the Pearl Harbor aquifer. It was concluded that a mathematical model can be used as a tool in the management of groundwater development in a thick Ghyben-Herzberg aquifer. Improvement of system simulation may be achieved by adding a mass transport element to study hydrodynamic dispersion within a transition zone where fluid density changes gradually.


Technical Report No. 140
ENVIRONMENTAL ASPECTS OF KAPA’A LANDFILL, KAWAINUI, O’AHU HAWAII

Michael J. Chun and Gordon L. Dugan
September 1981

ABSTRACT
The operation of the City and County of Honolulu, Kapa’a Sanitary Landfill, located next to Kawainui marsh on Windward Oahu, Hawai’i, raised concern over the possibility that landfill leachate could have adverse effects on the marsh. Thus, this study established six sampling sites each for surface water, groundwater, and combustible gas. Analyses were conducted for typical surface water and leachate parameters. The combustible gas monitoring was primarily for methane. There was obvious interchange of the marsh water and groundwater, with the higher mineral constituents of seawater intrusion being more evident in the monitoring wells with lower water levels. The outstanding characteristic of leachate, COD, with a reported typical concentration of 18,000 mg/l, was only found at a maximum median value of 38 mg/l in one of the six monitoring wells, while its surface water sampling station counterpart was nearly the same, 39 mg/l. No particular consistent correlation could be found to relate individual constituent concentrations of the surface water stations or monitoring wells to groundwater levels, rainfall, or seasonal and/or annual changes. If leachate is indeed entering the underlying groundwater its effect at this time would have to be considered minor. It was determined that no methane was detected in the gas monitoring wells.


Technical Report No. 141
IRRIGATION OF CALIFORNIA GRASS WITH DOMESTIC SEWAGE EFFLUENT: WATER AND NITROGEN BUDGETS AND CROP PRODUCTIVITY

Linda Lea Handley and Paul C. Ekern
December 1981

ABSTRACT
Californiagrass (paragrass) irrigated with effluent from secondarily treated domestic sewage showed excellent response as a means for disposal of large amounts of water, effective removal of nitrogen, and high production of excellent fodder.
This grass, already well established in Hawaii, is used for pasture and fodder, endures flooding, and because of its allelopathic habit forms dense, easily maintained monostands. The water, nitrogen, and biomass budgets of the grass over a 17-mo period, from April 1979 through August 1980, were measured in eight large percolate-style lysimeters filled with the Lahaina series soil (Tropeptic Haplustox). The experiment was conducted on the grounds of the Mililani Wastewater Treatment Plant in central 0’ahu, Hawaii. Under irrigation rates which reached as great as 98 mm/day 5 days a week, consumptive use of water by the grass averaged 4 mm/day and was linearly correlated with biomass production. The monthly effluent nitrogen content ranged from 17 to 59 mg/l with an average level of 34 mg/l. With effluent nitrogen application rates which ranged from 475 to 2 600 kg/ha/yr, an average 69% was harvested in the grass, 3% percolated, nearly 28% was denitrified, while the soil nitrogen status remained unchanged or decreased slightly. Even with the highest effluent irrigation rates, nitrate nitrogen levels in the percolate remained less than the 10 mg/l recommended for maximum potable water. Crop productivity was linear with applied nitrogen. Dry weight averaged 150 tons/ha/yr, with a maximum short-term productivity equivalent to 193 tons/ha/yr. The calculated crude protein content with the highest nitrogen application rates was 13%, while the caloric value was 4 000 kcal/kg, and no nitrate nitrogen levels in the forage exceeded 0.1%.


Technical Report No. 142
WATER TRANSFER STRATEGY ENERGY VS. AGRICULTURAL USE

Yu-Si Fok and Chi-Pin Chang
March 1982

ABSTRACT
In some arid and semiarid regions where most water is appropriated for irrigation, water has been recognized as the most important limiting factor for energy development. Therefore, a water transfer from agricultural to energy use should be considered. In this study, water values for energy and food production are first analyzed. Next, problems associated with transferring water from agriculture to energy are discussed. Then, an agricultural energy-water transfer model and an agricultural crop-production model for compensating crop production losses due to water transfer are derived. Finally, to seek an optimum development scale, a trade-off methodology which could be implemented by high-level decision-makers is proposed to coordinate the profits from agricultural water transfer and their related environmental impact. An example of the agricultural energy-water transfer model and trade-off is shown and conclusions drawn.


Technical Report No. 143
WATER CONDUCTION IN HAWAII OXIC SOILS

Richard E. Green, Lajpat R. Ahuja, She-Kong Chong,
L. Stephen Lau
August 1982

ABSTRACT
Oxic soils on Oahu were studied to develop and test simplified methods of determining the hydraulic conductivity of unsaturated soils, to test some simple infiltration models, and to assess the utility of soil survey mapped units in defining hydrologically similar soils. Field measurements of water infiltration and redistribution were accomplished on 21 sites located on the Lahaina, Molokai, and Wahiawa soil series. Water retention curves measured on undisturbed soil cores from the AP1, Ap2, and B horizons of each site provided a means of determining the downward flux of water during redistribution from soil water suction measurements over time. These data allowed calculation of hydraulic conductivities (by a detailed Darcy analysis) of soil at various depths in the soil profile and for a range of water contents and suctions. The detailed analysis and field infiltration data provided a means of evaluating two new simplified methods of determining hydraulic conductivity functions of well-drained soils; the new methods are sufficiently accurate and economical to be used in watershed characterization. Also., field measured sorptivity and water redistribution data were used to successfully predict cumulative infiltration with the Talsma-Parlange and Green-Ampt equations, respectively. Statistical analysis of field and laboratory data suggested that soil map s of central Oahu would not be particularly useful in delineating soil areas of relative homogeneity with respect to hydrologic properties. These ,results further emphasize the need for simple methods to characterize hydrologic properties of field soils.


Technical Report No. 144
WATER QUALITY OF AIRPORT STORM RUNOFF

Elizabeth Christakos-Comack and Gordon L. Dugan
July 1982

ABSTRACT
The quality of natural and induced storm runoff was ascertained from the 11.33 x 106 m2 (2800 acre) Honolulu International Airport (daily average air traffic volume of about 1000 planes and a mean annual rainfall of approximately 508 mm [20 in.]) by incorporating two monitoring schemes, the wet season and the dry season. The wet-season monitoring involved collecting storm runoff samples during and following rainfall events at established airport sites on paved surfaces. The dry-season monitoring scheme consisted of enclosing a 1.0-m2 (10.8-ft2) area, applying deionized water, and then collecting the wash water, leached chemicals, and sediments by a heavy-duty vacuum cleaner. Phenol, mercury, and turbidity exceeded the primary drinking water regulations, while pH, manganese, and total dissolved solids at times exceeded secondary drinking water regulations. Grease and oil concentrations showed a definite decrease from the Terminal Building (service and fueling area) to the outer drainage sites. High technology treatment, costing nearly four times the present cost of municipal water, would be required to meet potable water requirements; however for subpotable use, an equalization basin could be constructed for one-half the cost of municipal water. The 1985 projected water demand volume could be met by recovered storm runoff.


Technical Report No. 145
EXPOSURE TO MICROBIAL AEROSOLS FROM ACTIVATED SLUDGE TREATMENT

Arnold W. Lam and Reginald H.F. Young
November 1982

ABSTRACT
Viable pathogens are generally present at every stage of wastewater treatment. Thus a potential airborne infectious pathway due to microbial aerosols exists, particularly at activated sludge treatment plants. In this study the concentration of sewage-borne indicator bacteria and viruses in effluent aerosols was determined and the exposure to such aerosols by treatment plant workers was estimated. Initial aerosol collection with fog-gage screen collectors yield erratic results due especially to lack of control over sampled air volume and slit openings too large for effective collection. Standard Andersen and glass impinger collectors were used throughout the field study. Areas downwind of aeration basins yielded as much as 1 657 CFU/m3 total bacteria and 1.8 PFU/m3 coliphage. These aerosols were mostly 2.1 to 3.3 gm droplet nuclei with a high potential for inhalation and bronchial retention. The inhalation of microbial aerosols by Wahiawa treatment plant workers was estimated to be between 48 to 94 total bacteria/person/day above background levels. The inhaled total coliform level may average 8 to 27 CFU/ person/day. This usually short duration and sometimes intense exposure could not be implicated directly to cause adverse health effects. Correlations of statistical tabulations of sick-leave illness with degree of exposure were not significant at the 0.01 or the 0.05 level.


Technical Report No. 147
POPULATION BIOLOGY IN SMALL HAWAIIAN STREAMS

Robert A. Kinzie, III and John I. Ford
October 1982

ABSTRACT
Intensive stream surveys were conducted on Maui and Kauai in Hawaiian island streams during October 1979 through 1982 to investigate whether the presence of predaceous eleotrids in terminal reaches of low-gradient streams excluded the rare goby, Lentipes concolor, from this habitat and restricted it to higher elevations, An attempt was also made to determine whether a correlation exists between seasonality of stream discharge patterns and the two life history parameters (spawning and recruitment) of the indigenous, diadromous species. Two small perennial streams, Puaaluu and Pepeiaolepo, on the island of Maui, and another small stream, Maunapuluo, on the precipitous Na Pali Coast of Kauai were selected as study areas. Although evidence indicated that Eleotris sandwicensis preys upon gobies and rarely coexists with Lentipes, many other factors influence the effectiveness of Eleotris as a predator. Factors affecting the distribution and abundance of Lentipes are complex. No sharply defined periodicity was found in the recruitment of diadromous fishes, crustaceans, or mollusks. In-stream factors, among-stream and among-island differences in physical and biotic parameters apparently make recruitment into small Hawaiian streams an event in which chance plays a dominant role. In larger streams these stochastic processes may be averaged out and populations of these indigenous animals are more stable. The importance of these physical, biotic factors in determining the disturbance of populations of native stream fauna is discussed.


Technical Report No. 148
SOIL PARAMETERS AND SAMPLING SCHEME FOR CHARACTERIZING SOIL HYDRAULIC PROPERTIES OF A WATERSHED

Eshel Bresler and Richard E. Green
December 1982

ABSTRACT
Watershed modeling, which incorporates the stochastic nature of the hydraulic properties of the land surface and rainfall, requires a mathematical description of watershed variability, including the frequency distribution of key hydrologic parameters and the spatial structure of variances, Heterogeneous watersheds require extensive sampling to characterize the spatial distribution of a property, such as hydraulic conductivity, which is frequently required as input to model calculations of infiltration and runoff. Since hydraulic conductivity, K, varies with water content, e, and soil water pressure, h, the K(e) and K(h) relationships can be conveniently represented by parameters in mathematical expressions relating these variables. The parameters of three different equations are examined as indices of the hydraulic properties of Oxisol soils in Hawaii’s Pearl Harbor watershed. When what to measure and how to mathematically express the results is decided, the number and location of field-measurement sites in a particular watershed are determined. Geostatistical concepts are applied to design a sampling scheme for a specific watershed in which the measured value of a hydrologic property or index at a given point is correlated with other measured values of the property that is dependent on the distance between sampling points. Required statistical parameters for the geostatistical approach are the mean, variance, and autocorrelation function or variogram. Criteria are specified for selecting the location and smallest possible number of observation points to best estimate the statistical parameters. The results suggest that 30 measurement sites are the minimum sample size for estimating the parameters required for stochastic modeling. The proposed sampling procedure is illustrated with a sampling strategy for a portion of the Pearl Harbor watershed.


Technical Report No. 149
WATER RESOURCES BIBLIOGRAPHY OF HAWAII

Faith N. Fujimura and Edwin T. Murabayashi
March 1983

ABSTRACT
The previous Water Resources Research Center bibliographies (Technical Report Nos. 50 and 88) were evaluated by the project staff, assisted by an advisory committee to determine how this bibliography could be improved. As a result of the discussion and evaluation, the order and presentation of the entries in the Annotated Listing were revised. The former threepart code was simplified to a two-part code consisting of the first five letters of the primary author’s last name and the last two digits of the year of publication. The title of the report or article is displayed first in bold type for readability, followed successively by the annotation; author(s); keywords; repository, including the call number; and then by the facts of publication, such as the journal name, volume, number, inclusive pages, and the year of publication. Although the original research approach was to include publications issued between 1971 through 1978, earlier as well as more recent publications have been included. Secondary sources of information that were also used in compiling information included the Engineering Index, Selected Water Resources Abstracts, and the Water Resources Scientific Information Center.


Technical Report No. 150
WATER RIGHTS, WATER REGULATION AND THE “TAKING ISSUE” IN HAWAII

William Kloos, Nathan Aipa, Williamson B.C. Chang
May 1983

ABSTRACT
The unique situation concerning water rights in Hawaii presents some particularly difficult legal questions. This report analyzes the constitution, “taking” issues involved if Hawaii were to move from its present, judicially created system of water rights to a system allocating water based on limited-duration permits. Such a problem arises under the fifth amendment of the United States Constitution (prohibiting the taking of property without just compensation) because present Hawaiian water rights, namely riparian, appurtenant, and konohiki water rights, could be considered “property”. Replacing such rights with permits of limited duration, or the failure to grant a permit to an existing inchoate use, might therefore be considered a taking. Hence, the issue as to whether or not compensation in such cases is constitutionally compelled casts a pall of legal and economic uncertainty over the adoption of a permit system. This report develops a model for answering these questions based on the following steps: (1) the determination of the present state of water rights, (2) ascertainment of the degree to which these rights constitute “property” in a constitutional sense, (3) an assessment of the degree to which a comprehensive regulatory system is required by the constitutional amendment on water resources, (4) a discussion of the desirability of a limited-duration permit system,(5)the derivation of a test for determining whether a taking has occurred, and (6) the isolation of different factual patterns which would raise a taking question. The constitutional analysis proceeds under the assumption of a pre-McBryde state of affairs since this presents a ‘worst case’ scenario and magnifies the constitutional issues involved. In conclusion, a limited duration permit system is recommended as a constitutionally permissible and viable means of maintaining the needed flexibility to meet future demands and shifting uses.


Technical Report No. 151
WATER BALANCE OF THE PEARL HARBOR-HONOLULU BASIN, HAWAI’I, 1946-1975

Giambelluca, Thomas
1983
151 pages


Technical Report No. 152
STREAM-WATER STORAGE IN THE OCEAN BY USING AN IMPERMEABLE MEMBRANE

Murabayashi, Edwin T.
1983
64 pages


Technical Report No. 153
WATER QUALITY OF AIRPORT STORM RUNOFF PHASE II

Gordon L. Dugan
May 1983

ABSTRACT
The quality of natural and induced storm water runoff from several smaller public airports in Hawaii (air traffic volume of approximately 130 to over 350 airplanes per day) was compared to results from the previous Phase I study of the Honolulu International Airport that handles daily nearly 900 airplanes. The mean annual rainfall at these airports ranges from approximately 381 mm (15 in.) to nearly 3 251 mm (128 in.). Two basic storm quality monitoring schemes were incorporated, the wet season and the dry season. The wet season monitoring involved collecting storm runoff samples from paved surfaces during and following rainfall events at a specific airport. The dry season monitoring scheme consisted of enclosing a 0.25-m2 (2.69-ft2 ) area, applying deionized water, and then collecting the wash water, leached chemicals, and sediments by a hand bilge pump. As was the case for the storm runoff quality from the previous study of the Honolulu International Airport, the runoff from the smaller airports also contained mercury and turbidity that significantly exceeded the primary drinking water regulations, while concentrations of phenol and carbon chloroform extract definitely indicated that petroleum-derived products would be too high-and expensive to remove-for consideration as an alternate drinking water supply. However, the water, if collected and stored, could serve as a source of subpotable water.


Technical Report No. 154
CLOSTRIDIUM PERFRINGENS AS AN INDICATOR OF STREAM WATER QUALITY

Roger S. Fujioka and Lyle Shizumura
June 1983

ABSTRACT
The mCP medium devised by Bisson and Cabelli in 1979 was used to recover Clostridium perfringens from sewage and stream. This membrane filtration method proved to be uncomplicated and reliable. Of 98 presumptively positive colonies recovered from various stream samples, 89 or 91% were confirmed as C. perfringe-ns by using biochemical tests., whereas only 1 of 29 (3%) of the presumptively negative colonies was subsequently confirmed as C. perfringens. The quality of streams receiving treated and chlorinated sewage effluent was determined by analyzing the effluent entering the stream as well as stream samples above and below the effluent discharge site for fecal coliform (FC), fecal streptococcus (FS), and C. perfringens (CP). Chlorination was shown to drastically reduce the concentrations of FC and FS, but not CP in the sewage effluent. As a result. the concentrations of FC and FS in the chlorinated effluent were less than the natural concentrations of these bacteria in the stream, whereas the same effluent contributed significantly more CP than was naturally present in the stream. Thus, analysis of stream water for CP but not FC or FS clearly indicated the input of effluent into the stream. Moreover, the FC:CP ratio was useful in determining the quality and distance of a major source of pollution within a stream.


Technical Report No. 155
ECONOMICS AND LAW OF COMPENSATION: NATURAL RESOURCES POLICY

Stephen 0. Andersen
August 1983

ABSTRACT
Most economists advocate full compensation for natural resource use and for personal injury. The intent of these positions i8 to assure proper resource allocation and equity. However, this advocacy often neglects nonmarket re-sources and perspectives of future generations. This neglect i8 compounded by the separation of legal process and economic analysis. As a consequence many economists fail to understand how incomplete compensation is and lawyers frequently find economic analysis too naive and obscure to be useful. In this report economic and Legal theories are described. contrasted, and integrated in a pragmatic conceptual framework. Causes of inadequate compensation are defined using a case-study methodology. Two types of case studies are presented. The first summarizes the published record of compensation for privately induced damage to natural environments; the second presents the results of an original survey on mitigation to environmental impacts of contested water projects. Compensation in both cases is inadequate. in terms of equity and eliminating externalities. because of biased institutional factors. To make compensation more adequate. changes in property rights. liability rules. and insurance are suggested in combination with enhanced public trust doctrine.


Technical Report No. 156
MEASURED EVAPORATION IN HIGH RAINFALL AREAS, LEEWARD KO’OLAU RANGE, O’AHU, HAWAII

Paul C. Ekern
October 1983

ABSTRACT
An evaporating surface made from a dark, porous carborundum stone, 6-in. (152.4-mm) in diameter, wetted by capillary rise from a plastic reservoir and shield from rainfall by a clear plastic cover was designed for rainy areas. Class A pan evaporation at five different sites was 0.6 the water loss from corresponding evaporimeters Water use by Californiagrass was 1.1 pan evaporation and 0.66 the water loss from the evaporimeter. Evaporation, rainfall, and pertinent meteorological factors were measured at one ridge and four valley sites on the Manoa transect in southern 0’ahu and at one valley and eight ridge sites on the Kipapa Ridge transect on the Leeward Ko’olau Range slopes in central Oahu. Water use on the Kipapa transect was that predicted by the Priestley-Taylor relationship, while water use on the Manoa transect exceeded that predicted with positive advection from the urban surroundings and probable subsidence of the air from the Kololau crest. Measured rates exceeded those from empirical relationships based on extrapolation of pan evaporation measurements. Of the near normal 1981 rainfall of 149 in. (3 784.6 mm), runoff was 27%, evaporation 28%, and deep percolate 45% for the Kipapa watershed water balance. Both runoff and evaporation were greater and percolate less than that given for the 1958 water balance. Direct interception of cloud water added an amount less than 2% of the rainfall on the watershed. Maximum short-term, deep percolation rates were no greater than 1.6 in. (40.64 mm)/day and runoff was 0.53 rainfall 1.28.


Technical Report No. 157
DBCP VOLATILIZATION FROM SOIL AND WATER: A LABORATORY STUDY WITH TWO HAWAIIAN SOILS

Katherine W. Pringle, Clark C.K. Liu, Richard E. Green
August 1984

ABSTRACT
DBCP (dibromochloropropane) has been used as a soil fumigant for nematode control for decades by the Hawaii pineapple industry. Recent detection (parts-per-trillion range) of the fumigant in potable well water has spurred a study of the behavior of DBCP in its Hawaiian environment. A volatile trapping apparatus was developed which proved to be highly efficient in capturing volatilized DBCP. Rates of DBCP volatilization from water were established for variations in air flow rate, temperature, and DBCP solution concentration. Measurements of cumulative DBCP volatilized at three solution concentrations indicated the applicability of Henry’s law for solution concentrations up to 35 ug/ml. A soil cell, patterned after that developed by Spencer and associates, was used to determine volatilization rates for DBCP mixed uniformly in surface soils from the Wahiawa series of 0’ahu and the Maile series of Hawaii Island. The effect of Wahiawa soil-water content on DBCP volatilization (without water loss) was evaluated at water contents of 2.3, 8.5, 13.5, and 31.6% by volume. DBCP vapor flux was lower at 2.3% water content than at higher water contents for the first three days, possibly because of higher adsorption on the very dry soil. An untreated 0.02 m thick soil layer placed above DBCP-treated soil greatly retarded DBCP volatilization during the first two days. The calculated effective liquid-vapor diffusion coefficient, De, for Wahiawa soil increased with soil water content from 6.1 x 10-4 cm2/s at 2.3% water content to 2.6 x 10-3 cm2/s at 31.6% water content.


Technical Report No. 158
MICROMOLLUSCAN ASSEMBLAGES IN MAMALA BAY, O’AHU, 1974-1982

E. Alison Kay and Regina Kawamoto
December 1983

ABSTRACT
The benthic communities in Malama Bay, Oahu have been monitored since 1974 to assess the extent to which the introduction of sewage effluent at about a 70-m depth has affected the system. The index organism utilized are micromollusks, mollusks less than about 7 mm in greatest dimension. Replicate sediment samples were obtained by modified Petersen dredge from 11 stations at 15- to 120-m depths between 1974 and 1981; samples from the diffuser and the ZID boundary were obtained by submersible-operated grab in 1982. Aliquots of sediment were sorted for micromollusks and analyzed by Q-mode cluster analysis. relative species compositions relative abundance, species diversity, and dominance. Three micromolluscan assemblages were distinguished. A Tricolia-rissoid dominated assemblage in an algal and rubble-associated assemblage of microherbivores derivative of the reef. An infaunal assemblage with about 30% of the mollusks’ carnivorous, parasitic and/or deposit feeders is associated with the occurrence of beds of the bivalve Pinna. The habits of the mollusks of the third assemblage. the dialid assemblage, are not known. Mean micromolluscan abundance tends to increase with depth; number of species and species diversity decreases with depth. Abundance is not significantly different between pre- and post-discharge stations. The Tricolia assemblage was the most frequently occurring assemblage under pre-discharge conditions; the infaunal assemblage the most frequently occurring assemblage under post-discharge conditions. In the submersible-obtained samples. only the dialid assemblage was represented at the ports of the diffuser and only the Tricolia assemblage at the ZID boundary. It is suggested that the micromolluscan assemblages in Malama Bay are distributed in a continuum throughout the bay, their boundaries associated with different type of sediment. No major changes in the benthos associated with the introduction of sewage effluent were detected in this study, but variations in pattern of assemblage occurrence may be the result of changes in sediments associated with diffuser activity.


Technical Report No. 159
DECONTAMINATION OF CHROMIUM-CONTAMINATED SOIL IN HAWAII

Gordon L. Dugan, Henry K. Gee, L. Stephen Lau
March 1984

ABSTRACT
Approximately 1 841 m3 (65,000 ft3) of chromium-contaminated soil, classified as hazardous waste (>5 mg/l chromium extract concentration as measured by the EP toxicity test) was found near the new pipe shop at the Pearl Harbor Naval Shipyard on Oahu. Hawaii. Unless treated to a safe level, the contaminated soil required disposal in a Class 1 landfill. the closest being in the continental United States. Based on simple laboratory and pilot plant procedures, the project proved that chromium could be effectively leached from the soil to a safe level by using a nearly 1:4 weighted soil to water ratio; reducing the pH to 2.5; adding sodium metabisulfite to chemically reduce chromium from Cr+6 to Cr+3; and then raising the pH to 8.5 to precipitate the chromium from solution. A full-scale operation, following the technology that was developed. successfully treated the soil to a safe level and subsequent testing of the treated soil at the disposal (landfill) site confirmed the effectiveness of the treatment operation.


Technical Report No. 160
CHEMICAL CONSTITUENTS CF RAINFALL AT DIFFERENT LOCATIONS ON OAHU, HAWAII

Gordon L. Dugan and Paul C. Ekern
May 1984

ABSTRACT
Rainfall sampling, which began in 1981 before the 1982 to 1983 El Nino and continued into 1984 on Oahu in Hawaii, represented sites with widely different rainfall amounts. Samples stored under refrigeration prior to analysis were analyzed for pH and for the major cations, chloride and sulfate, and the nitrogen series. For the stored samples, the rainiest site was acidic with median pH 4.9, and rainfall weighted pH 4.77. Samples analyzed immediately on receipt at the laboratory had median acidity of pH 4.2 and rain-weighted pH 4.22. Samples that included some cloud water had acidity with a median pH 5.1 and rainfall weighted pH 5.17. Samples taken before and after the eruption of El Chichon in April 1982 showed no apparent effect of the stratospheric sulfur on rainfall acidity. Electrical conductivity of the rainfall was equivalent to cation concentrations of 1 to 10 milliequivalents per liter. Chloride, a major cation, decreased with distance from the ocean sources. Sulfate values in the rainwater increased during southerly flow when Kilauea volcano was erupting, so that the sulfate to chloride ratio increased to tenfold that for seawater. Organic nitrogen forms made up about 40% of the total nitrogen content of the rainfall, and calculated organic-N loadings from the annual rainfall had values from 4.39 to 1.62 kg/ha/yr. These pH values of 4.2 to about 5.0 support the contention that the acidity in naturally occurring rainfall in remote areas has a pH slightly below 5.0.


Technical Report No. 161
REPLICATION OF HUMAN ROTAVIRUS IN TISSUE CULTURE: RECOVERY AND DETECTION IN FECAL, SEWAGE, AND NATURAL WATER SAMPLES

Roger S. Fujioka, Edward B. Siwak, Philip C. Loh
June 1984

ABSTRACT
Human rotavirus is the major cause of gastroenteritis among young children. To replicate this virus, sensitive methods using standard tissue culture systems are required. The project goal was to develop laboratory capability to recover and detect this infectious rotavirus in fecal, sewage, and natural water samples. Using simian rotavirus (SA-11) as a model system and an enzyme-linked immunosorption (ELISA) test capable of detecting high concentrations of rotavirus, the protamine sulfate method was determined as superior to the aluminum chloride precipitation and polymer two-phase methods for recovering rotavirus from sewage. The ELISA method was very effective in detecting rotavirus in stool samples of children. Stools from children not displaying clinical symptom of rotavirus infection were negative for rotavirus, whereas 43 to 58% of stools from children displaying clinical symptom of rotavirus infection was positive for rotavirus. The results suggested an association of increased rotavirus infections during the winter months in the state of Hawaii. Stools positive for rotavirus by the ELISA test were used as inoculum to develop methods to replicate human rotavirus in the cell culture system. After many unsuccessful attempts, human rotavirus was cultured after two passages in primary cynomolgus monkey kidney cells. Human rotavirus which replicated in the primary monkey kidney cells was shown to be capable of replicating in continuous monkey kidney cell lines such as the MA-104.


Technical Report No. 162
MICROMOLLUSK MONITORING AT BARBERS PT. SEWAGE OUTFALL O’AHU, HAWAI’I

E. Alison Kay and Regina K. Kawamoto
March 1984

ABSTRACT
The purpose of the 1981 to 1983 monitoring program at the Barbers Point Outfall on Oahu, is two-fold: to describe the benthic community by utilizing micromollusks as index species and to establish a data base for continuing community analysis. This report should be regarded as an initial step in an ongoing monitoring program. The conclusions as of the end of 1983 are as follows:
1. Analysis of the data indicates a consistent pattern of benthic community structure in the area of the Barbers Point Outfall at Honolulu, Oahu. Shifts in the distribution pattern of the assemblages are interpreted as due to natural variability in the system.
2. A comprehensive, systematic, computerized data base has been established for micromollusk data in SAS at the University of Hawaii computing Center. The data base contains all micromollusk data collected at Barbers Point and a Bay between 1973 and April 1983 (data from Sept., Oct., and Nov. 1983 are currently being entered in the data base). Included in the data base are values for physicochemical characteristics of the samples.
3. The current sampling program appears to be adequate at this time and should be continued in its present form through 1984.


Technical Report No. 163
IMPROVED EMITTER AND NETWORK SYSTEM DESIGN FOR WASTEWATER REUSE IN DRIP IRRIGATION

Donald R. McDonald, L. Stephen Lau, I-Pai Wu, Henry K. Gee, Stephen C.H. Young
July 1984

ABSTRACT
The problem of emitter (orifice) plugging inherent in drip irrigation systems was investigated. Plugging not only reduces the effectiveness of this most water conservative method but also excludes the use of low quality waters unless first processed with costly water treatment. A problem-solution approach was used to develop simple emitters and a network system that would minimize plugging to acceptable levels. Tests using secondary treated municipal effluent from the Mililani Wastewater Treatment Plant on Oahu, Hawaii, consisted of numerous plugging experiments supplemented by theoretical and laboratory studies. Tests showed that plugging, up to 25% or less, can be controlled by using size emitters and passing the effluent through a stationary 40 and 80-mesh screen; critical-size emitters are 0.03 in. for microjets and 0.019 in. for monotubes; higher operating pressure further reduces plugging percentages; flexible 0.15 in. slit orifices (at 15 psi) perform as well as the critical size rigid orifice but another round flexible orifice (rubber tube) was less successful; a multiple-inlet network design with critical-size emitters can minimize pressure and emitter flow variations along the drip laterals and was ideal for systems with large flow rates; and plugging was attributed to particles and fibers in the effluent.


Technical Report No. 164
WATER-USE COEFFICIENT’S AND RESOURCE MULTIPLIERS FOR O’AHU, HAWAII

Richard L. Bowen, PingSun Leung, Mary H. Vesenka
August 1984

ABSTRACT
The proliferation of the number of water multipliers in recent years has increased the likelihood that misunderstanding and misuse will occur by practitioners not well trained in the interindustry analysis. What is needed is a more standardized terminology and a more critical evaluation of the meaning and use of these multipliers. The this purpose, water resource multipliers were estimated for Oahu, and the usefulness of such multipliers for public planning and decision making in Hawaii are critiqued. The method of analysis used is the Leontief input-output or interindustry model. The Oahu model was developed from data used to construct the state input-output (I-0) model. Water use by economic sector was estimated from primary and secondary data. Three general types of water multipliers were estimated and evaluated for Oahu. The water-final demand coefficients can be useful in estimating water use under alternative development scenarios. The water multiplier was found to have limited value for planning in Hawaii. The waterincome ratio is supposed to quantify the tradeoff between sectoral income and water use. However, this ratio is conceptually troublesome and it takes multiplier analysis beyond its traditional positive role into the normative arena.


Technical Report No. 165
REPPUN V. BOARD OF WATER SUPPLY: PROPERTY RIGHTS, ECONOMIC EFFICIENCY AND ENSURING MINIMUM STREAMFLOW STANDARDS

Williamson B.C. Chang and James E.T. Moncur
September 1984

ABSTRACT
Two recent decisions of the Hawaii Supreme Court have substantially modified the ground rules governing water rights in the state. The principal economic result of these decisions is the limitations they impose, if they survive appeals, on rights of individual water users to exchange water rights. This report inquires into the values the Court appears to have had in mind in imposing such restrictions. From a legal standpoint, the paper argues that the Court’s decision in Reppun v. Board of Water Supply sought not so much to protect the taro farmers from loss of water as to protect in-stream water uses such as fishing and aesthetics. A brief summary of the economics of growing taro in Waihe’e Valley suggests that the water in question has much higher-valued uses than traditional taro cultivation, and notes a broad framework of principles that would allow efficient allocation of water between users, uses and places of use, covering traditional as well as in-stream uses.


Technical Report No. 166
ACTIVATED CARBON ADSORPTION OF LOW CONCENTRATION ORGANIC PESTICIDES IN WATER

Gordon L. Dugan, Henry K. Gee, Kevin M. Oshiro,
L. Stephen Lau
December 1984

ABSTRACT
A series of thirty separate. experimental laboratory bench-scale runs were conducted in which concentrations of EDB and DBCP in water, ranging from 2,170 to 10,000 parts per trillion (ppt), were treated by passing various quantities through both standard and fine-grained Calgon and Darco granulated activated carbon (GAC). The results of the experiments indicate that Calgon is more efficient than Darco in removing EDB and DBCP, that fine-grained GACs are more efficient than standard GACs, that EDB is removed more efficiently than DBCP, and that when a mixture of EDB and DBCP is passed through the same GAC, the pesticide removal efficiency of the GAC–based on fine-grained Calgon–decreases significantly. At single concentrations of EDB, no detectable concentrations (at the 10-ppt level) were noted when the maximum flow-through GAC loading rates were 259 gal/lb-day (1.50 ml/g-min). Based on extrapolated results, the GAC requirement for 100 ppt pesticide concentrations is estimated to be approximately 1.0 lb/ 1.0 mil gal.


Technical Report No. 167
WATER PRICING, CONSERVATION, AND URBAN WATER MANAGEMENT

James E.T. Moncur
October 1984

ABSTRACT
The potential for using water pricing was investigated as a tool to promote conservation efforts of the water supplies of Oahu. Traditional approaches, in Honolulu as elsewhere in the United States, to an impending long-term shortage of water relative to demand emphasize augmenting the supply of water, on the implicit ground that consumers “need’ certain quantities, whatever the price. A survey of Honolulu single-family residential customers of the Honolulu Board of Water Supply was conducted in the spring of 1983. Data generated in this survey allow the specification and testing of a fairly traditional economic model of water demand. Results of this model indicate that marginal price, household income, and rainfall all significantly affect the quantity of water demanded by Honolulu residents. Price, in particular, evidently has a low but non-zero elasticity, indicating that pricing policy will indeed serve as a tool in attempts to promote water conservation and thus lengthen the viability of conventional and less expensive water sources on Oahu.


Technical Report No. 168
RECOVERY OF FALSE POSITIVE FECAL STREPTOCOCCUS ON KF AGAR FROM MARINE RECREATIONAL WATERS

Roger S. Fujioka, Aaron A. Ueno, Owen T. Narikawa
July 1984

ABSTRACT
Fecal streptococcus (FS) is the most often used alternative to fecal coliforms to assess the quality of recreational water. Because the reliability of KF agar to recover PS bacteria has been reported to approach 100%, this medium was used to test the water quality of Hanauma Bay which was suspected as the source of disease transmission to a group of swimmers using this beach park. Marine water samples from Hanauma Bay, 0’ahu, were characterized by low concentrations of fecal coliforms and Clostridium perfringens but unusually high concentrations of presumptive FS when KF agar was used. Most of the presumptive FS colonies on KF agar could not be verified and was therefore concluded to be “false positive”. At least two types of catalase-positive bacteria were determined to be responsible for the formation of false-positive colonies on KF agar: one, a gram-positive coccus; the other, a gram-negative, NaCl-requiring bacillus. These false positive, FS-like bacteria were present in marine recreational waters obtained from 15 other sites, although at lower concentrations than in Hanauma Bay. The presumptive FS counts on KF agar ranged from 53 to 1205/ 100 HE for the 15 marine sites. In contrast, less than 20 presumptive enterococcus colonies were recovered and readily confirmed as true enterococci when mEnterococcus agar was used to assay these samples. Thus in tropical climates such as Hawaii, KF agar and its recommended technique should not be used to assay marine waters for F’S. Three modifications in the KF agar technique could however prevent the bacteria present in marine waters from producing false-positive FS colonies on KF agar: delete NACL from KF agar, increase sodium azide concentrations in KF agar, or incubate KF agar anaerobically rather than aerobically.


Technical Report No. 169
ELECTRICAL RESISTIVITY INVESTIGATION OF SCHOFIELD HIGH-LEVEL WATER BODY, OAHU, HAWAII

Shettigara, K.V.
1985
136 pages


Technical Report No. 170
WASTEWATER IRRIGATION FOR ALFALFA, GUINEA GRASS, AND PAPAYA PRODUCTION IN HAWAII

Henry K. Gee, Edwin T. Murabayashi, Reginald H.F. Young
September 1985

ABSTRACT
A preliminary investigation was undertaken to determine the effectiveness of using treated municipal wastewater for irrigation and nutrient stripping by three agricultural crops. Alfalfa and guinea grass were chosen because local production could reduce the large amounts of alfalfa cubes and hay imported for the dairy and cattle industry. Papaya was selected because it is a developing export crop with an established marketing infrastructure. Health hazards were not a factor in this study. Forage crops are consumed by animals before reaching the human food chain. Papayas are harvested 5 to 10 ft above the ground (where drip irrigation lines were located), with no direct contact by the irrigated wastewater. Alfalfa produced 16.6 tons/acre/yr dry wt or 85 tons/acre/yr wet wt; guinea grass yielded 21.0 tons/acre/yr dry wt or 126 tons/acre/yr wet wt. Guinea grass contained 1.5 times more water than alfalfa, and although dry wt production was higher, its crude protein content was lower, amounting to1.96tons/acre/yr compared with 3.49 tons/acre/yr for alfalfa. Both forage crops stripped N from the effluent but guinea grass was more efficient than alfalfa. Nitrate levels of the guinea grass percolate were below the drinking water limit of 10 mg/l as NO.-N after the first harvest, while alfalfa gradually increased its stripping ability and exceeded the limit after the fifth harvest.
Difficulty was encountered in obtaining a viable crop of papaya. Of the transplanted seedlings, only 25% survived and became established. Thus, female papaya plants were not culled and fruit production rate was measured for all the plants. Extrapolation of the total yield of 122,000 lb/acre/yr, of which 30% was marketable, indicated papaya production amounted to 36,000 lb/acre/yr which is comparable to commercial production in Kapoho, Hawaii.


Technical Report No. 171
HABITAT MODELING OF HAWAIIAN STREAMS

Robert A. Kinzie, III; John I. Ford; Andrew R. Yuen; Sterling J.L. Chow
October 1986

(REV. 1988)

ABSTRACT
An evaluation of the Instream Flow Incremental Methodology (IFIM) was carried out to assess the applicability of this technique to Hawaiian streams. Hydraulic simulations were made for two study reaches on Nanue Stream, Hawaii, and one study reach on Wainiha River, Kaua’i. Four simulations were carried out and compared: WSP used alone, IFG4 using several data sets, WSP and IFG4 in combination, and IFG4 using only a single data set. Habitat utilization and preference were determined for three stream gobies, Awaous stamineus, Sicyopterus stimpsoni, and Lentipes concolor. IFIM was used with habitat data for S. stimpsoni to determine weighted usable area and to carry out time series analyses for Wainiha River. Results of the hydraulic simulations indicate that IFG4 using several data sets yields the best simulation of stream hydraulics. The WSP simulation program does not appear to be suitable for many Hawaiian streams, particularly smaller streams, with high gradients, or streams with complex channels. The habitat utilization studies indicated that the three species used available habitat in different ways giving rise to some microhabitat differentiation. Tests were made to determine if habitat preference curves derived from fish in one stream could be transferred to another stream. Tests of transferability indicated that habitat utilization data collected from one stream could not be reliably transferred to another stream. Finally it was concluded that IFIM is suitable for certain Hawaiian conditions provided that appropriate precautions in project design, data collection, and simulation studies are taken.


Technical Report No. 172
CARBONATE GEOCHEMISTRY AND HYDROGEOLOGY RELATIONSHIPS: LAURA, MAJURO ATOLL, MARSHALL ISLANDS

Stephen S. Anthony and Frank L. Peterson
January 1987

ABSTRACT
In carbonate aquifers diagenetic alteration of the aquifers host rock and the chemical interactions between groundwater and the carbonate sediments and rocks are important for groundwater quantity and quality relations. These processes result not only in the alteration of groundwater chemistry, but also influence the development of porosity and permeability, and thus groundwater occurrence and movement in carbonate aquifers. Likewise, the rates, directions, and mechanisms of fluid transport through aquifer pore-networks are basic to an understanding of @ diagenetic processes. In this study a hydrogeochemical approach is taken to decipher the occurrence and movement of groundwater in the Laura area of Majuro Atoll, Marshall Islands. The following questions are addressed: (1) what is the geochemical composition and depositional environment of the subsurface materials; (2) what are the diagenetic processes operating in the hydrologic regime; (3) what are the controls on these processes; and (4) what is the effect of depositional and diagenetic history on permeability and porosity characteristics of the aquifer? The stratigraphic section in Laura consists of two principal units: an upper unit of moderately permeable carbonate sediments, under-Laid by an extremely permeable carbonate rock unit. The sediment and rock units contain a calcium carbonate freshwater-seawater system, in which the freshwater nucleus occurs on the lagoon side of the island. Its movement is governed by an an-axisymmetric distribution of lithofacies and an increase in permeability with depth.
An effect of the an-axisymmetric distribution of fresh groundwater is a groundwater divide that is preferentially closer to the Lagoon shoreline than the ocean shoreline; thus, more of the island’s recharge is directed toward the ocean rather than to the lagoon. A longer flow path from the groundwater divide toward the ocean, coupled with a shallower high permeability carbonate rock unit, results in a thicker freshwater-seawater mixing zone in the sediments bordering the ocean than those bordering the lagoon. Thus, not only is the mixing zone thicker, but it also receives a greater amount of rainfall recharge. This thick, well-flushed mixing zone is the site of continuously occurring diagenetic reactions that are having a significant effect on the development of porosity and permeability. The diagenetic history of the lower carbonate rock unit and the upper carbonate sediment unit are the primary controlling factors in the occurrences and movement of groundwater in the Laura area of Majuro Atoll.


Technical Report No. 173
WATER CODE DEVELOPMENT IN HAWAII: HISTORY AND ANALYSIS, 1978-1987

Williamson B.C. Chang
February 1987

ABSTRACT
During the nine years since the enactment of the amendment to the state constitution calling for a water code, those proposing various codes have faced four main problems identified here as (1) the ownership question, (2) the question of which agency shall ultimately control water allocation, (3) relationship between the state and counties, and (4) the question of Native Hawaiian water rights. Early debate on various codes focused on the issue of ownership. Many parties incorrectly assumed that government regulation could only be based on government ownership of water. The confusion was exacerbated by the decision in McBryde v. Robinson which purported to give corporeal ownership of the water to the state. This report discusses limited duration permit systems that grant the government the power to allocate water without reliance on ownership. Two of the major issues focus on the proper governmental agency for regulation of water. The counties have opposed statewide control over water allocation for fear that the decisions made in Honolulu will not reflect local concerns and out of a concern that county land-use planning decisions will not be supported by water allocation decisions made by a state agency. Secondly, the Department of Health expressed fears that its water quality decisions could be bypassed by powers lodged in the Department of Land and Natural Resources. The last major issue focuses on respect for traditional Native Hawaiian water rights that are not clearly defined. The various codes present the possibility that such claims would be nullified. Such a scenario would represent a perpetuation of harm done to the Native Hawaiian which began with the alienation of land from the Hawaiian in the middle nineteenth century.


Technical Report No. 174
TRACE ORGANIC (DBCP) TRANSPORT SIMULATION OF PEARL HARBOR AQUIFER, O’AHU, HAWAII: Multiple Mixing-Cell Model, Phase I

Shlomo Orr and L. Stephen Lau
August 1987

ABSTRACT
Lumped parameter models were chosen to provide a preliminary appraisal of the fate of trace organics (DBCP) in a portion of the Pearl Harbor aquifer and to provide a management tool for policymaking. The models, which consider portions of the aquifer as mixing cells, extensively simplify the systems. Special attention focused on attenuation and travel time in the approximately 800 ft (244 m) thick, vadose zone. Pseudo first-order decay coefficients determined from pesticide residues in the topsoil were used to determine attenuation in the vadose zone. A separate mixing-cell model was developed for the topsoil to distinguish between the different mechanisms responsible for the attenuation of adsorbed pesticides, particularly leaching vs. volatilization. Thus, an alternative method that excludes the varying distribution coefficients is suggested to estimate the leaching fraction of strongly adsorbed pesticides. The results indicate that at least a decade will pass before the aquifer starts to recover and another five years before DBCP concentrations become undetectable. The concentration attenuation within the vadose zone is about three orders of magnitude greater than the concentration reduction resulting from dilution within the aquifer. The simulated concentrations are very sensitive to the decay coefficients determined for the unsaturated zone. We conclude that leachate concentrations as low as 0.1 ppb (ug/1) below the top few feet of soil can reach and contaminate deep goundwater, where (usually) the dilution is limited to less than 1:10. Due to the high persistence of many volatile organic carbons (dissolved in water) in very low concentrations, they can be considered as “conservative” tracers for modeling purposes.


Technical Report No. 175
MODELING OF TRACE ORGANIC (DBCP) TRANSPORT IN PEARL HARBOR AQUIFER, O’AHU, HAWAII: Method of Characteristics, Phase II

Shlomo Orr and L. Stephen Lau
September 1988

ABSTRACT
A numerical model, based on the method of characteristics (MOC), is used to simulate the transport of DBCP through the basaltic aquifer in Mililani and vicinity and to predict the potential downstream contamination including Waipio Heights Wells H. The Phase H modeling is intended to improve upon the Phase I mixing-cell model. For the two-dimensional solute transport model and the large scale used, the aquifer is considered as homogeneous and isotropic, the solute transport as occurring in the upper irrigation-return lens, and the dispersion as Fickian. The lowest and the most abundant concentration detected in the deep core samples was assumed to be the input concentration at the water table, deep below the pineapple fields. This rather optimistic assumption would render a rather optimistic recovery of the aquifer. The results suggest that predicted DBCP levels will decline to below 20 ppt for the Mililani wells around the year 2000. Waipio Heights Wells R would experience DBCP increase up to 22 ppt around the year 2000, then decline slowly. Increased pumpage from Mililani Wells 11 would hasten aquifer recovery. The mutual relationship between the calibration of the solute transport and the groundwater flow models emphasizes the need for a more precise flow model that more precisely predicts dynamic changes in pumping stresses and recharge. The two models show a general similarity in the prediction of aquifer recovery, which is, however, slightly faster in the mixing-cell model. The mixing-cell model tends to overestimate dispersion, the lateral in particular. Both models show that leachate concentrations as low as 0.1 ppb below the top few feet of soil can contaminate a deep aquifer.


Technical Report No. 176
CHEMICAL RESIDUALS TRANSPORT IN AGGREGATED SOILS: Mathematical Simulation by the Linear System Approach

Liu, Clark CK; Feng, Jing-Song
1988
45 pages


Technical Report No. 177
DRINKING WATER QUALITY DETERMINATION: An Evaluation of New Methods of Analysis

Roger S. Fujioka, Nipapun Kungskulniti, Samuel S. Nakasone
September 1987

ABSTRACT
The most recent edition of Standard Methods proposes the use of the presence-absence (P-A) test to assay drinking waters for Coliform bacteria and the membrane filtration (MF) method using two new media (M-HPC, R2A) to determine the concentrations of total heterotrophic bacteria in drinking water samples. These two methods were used to analyze selected samples of Honolulu’s drinking water which were being routinely analyzed for coliform bacteria and total heterotrophic bacteria tested by traditional methods from the Honolulu Board of Water Supply (BWS) and the Hawaii State Department of Health (DOH). Over a thirteen-month period, 200 water samples obtained by the BWS and 18 samples obtained by DOH were also analyzed for coliform bacteria using the P-A test and for total heterotrophic bacteria using the MF method by the laboratory at the University of Hawaii. The comparative results show that the P-A test is more sensitive than the most probable number (MPN) (P <0.01) and the MF methods (P <0.05) in recovering coliform bacteria. Moreover, the MF method using either the M-HPC or R2A media is more efficient in recovering total heterotrophic bacteria than the pour plate method (P <0.01). The P-A test for coliform bacteria and the MF method for total heterotrophic bacteria were determined to be feasible and reliable methods when applied to drinking water samples from Honolulu. These two new methods were recommended for use by the BWS and DOH.


Technical Report No. 178
HYDROGEOLOGIC CHARACTERISTICS OF SUBSOIL AND SAPROLITE AND THEIR RELATION TO CONTAMINANT TRANSPORT, CENTRAL O’AHU, HAWAII

Mark E. Miller, Richard E. Green, Frank L. Peterson, Rollin C. Jones, Keith Loague
June 1988

ABSTRACT
A detailed characterization was made of soil and saprolite core samples taken from seven locations in central O’ahu pineapple fields. Groundwater in the area is contaminated with trace amounts of the soil fumigants EDB, DBCP, and TCP. Samples were collected to a depth of 30 m in the unsaturated zone and tested for hydraulic and mineralogic properties to evaluate the geologic controls on contaminant transport from the surface soil to the groundwater. The geologic profile in the area consists of Oxisol surface soils grading into saprolite (highly weathered basalt). Soil water retention measurements conducted on tension table and pressure plate apparatus provided data for the determination of porosity, bulk density, water-retention curves, and poresize distributions. Hydraulic conductivity, as a function of water content and water tension, was estimated using the Marshall method. X-ray diffraction was used to determine the bulk mineralogy, and scanning electron microscopy (SEM) was used for detailed study of mineral morphology and composition and the degree of pore interconnections.
The hydrogeologic conditions of the unsaturated zone were found to be extremely heterogeneous relative to hydrologic and mineralogic properties. Porosities were high (0.4550.723), but generally over half of the pore space consisted of micropores. While not contributing much to water flow, the significant quantity of micropore water provides a temporary reservoir for solutes and could be expected to contribute to the retardation of pesticide movement in percolating water. The calculated saturated hydraulic conductivities ranged over five orders of magnitude(10-3 – 10-8 m/s). The SEM results suggested that preferential flow was occurring in channels between macropores and along joints. The mineralogy results showed the most intense weathering at shallower depths, with primarily Fe and Ti oxides occurring to a depth of 6 to 12 m, below which were mainly clay minerals. The highly weathered upper zone had lost the parent basalt structure and showed lower conductivities. The presence of kaolinite and halloysite closely correlated with pesticide residues in the subsurface; these clay minerals might have been entrapping the pesticides within their tubular structure. These residues are suspected to be weakly bound and might easily leach downward to the groundwater. The future impact of the residual pesticides on groundwater quality will depend on the rate of release of the entrapped pesticides and the degree of dilution by infiltrating water.


Technical Report No 179
AQUIFER IDENTIFICATION AND CLASSIFICATION FOR O’AHU: Groundwater Protection Strategy for Hawaii

John F. Mink and L. Stephen Lau
November 1987 (Rev. 1990)

ABSTRACT
In response to the need to identify and describe aquifers for each island of the state of Hawaii to serve as a framework for goundwater protection strategy, a program has been initiated to classify and assign codes to the principal aquifers of the State. This first report provides Aquifer Codes and Status Codes for the island of 0’ahu. The Aquifer Codes incorporate locational and descriptive indices, while the Status Codes indicate the developability, utility, quality, uniqueness and vulnerability to contamination of the goundwater resources. The codes were generated for Hawaiian conditions of groundwater occurrence and behavior in preference to employing the DRASTIC approach suggested by the U. S. EPA. Each Aquifer Type within an Aquifer System is assigned an Aquifer Code consisting of an eight-digit number. An Aquifer Code is unique and non repeatable in the State. Accompanying the Aquifer Code is a Status Code of five digits. A Status Code is specific to an Aquifer Code. The 0’ahu classification includes 6 Aquifer Sectors, 24 Aquifer Systems, and 90 Aquifer Codes.


Technical Report No. 180
DESORPTION AND LEACHABILITY OF SORBED DBCP RESIDUES IN HAWAII SOILS

Donna S. Buxton and Richard E. Green
March 1992

ABSTRACT
Sorption processes for Hawaii soils which contain highly sorbed dibromochloropropane (DBCP) residues were analyzed to assess the leachability of the residues and their potential as a source for goundwater contamination. Leaching potential was inferred from measurements of equilibrium distribution coefficients and rates of desorption considered in the context of convective and diffusive transport by water moving in structured soils. Two methods that exploit the volatile nature of DBCP were developed to quantify the partitioning of the nematicide into the sorbed, solution, and vapor phases. The indirect sorption method determined equilibrium distribution coefficients; the air-purge system measured the rate and extent of desorption. Both methods involved analysis of only the vapor phase of a soilpesticide system. Effective pollutant diffusion coefficients and diffusion times were calculated for DBCP movement out of soil aggregates.
The tightly bound sorbed DBCP residues are extremely resistant to desorption. The amount of pesticide from the sorbed phase that can contribute to groundwater contamination during any one rainfall event is on the order of a thousandth to a millionth the amount of the sorbed phase. Even under sustained rainfall or irrigation, it may take from days to months for DBCP to be released from soil aggregates. Thus, movement of surface-soil DBCP residues is not expected to result in future groundwater contamination; the residue concentrations are low, the desorption rate is low, and large travel times to groundwater enhance the likelihood of dispersion and degradation of DBCP.


Technical Report No. 181
ORGANIC CHEMICAL CONTAMINATION OF OAHU GROUNDWATER

Lau, L. Stephen
1987
153 pages


Technical Report No. 182
GROUNDWATER RECHARGE WITH HONOULIULI WASTEWATER IRRIGATION: Ewa Plain, Southern O’ahu, Hawai’i

L. Stephen Lau, W. Roy Hardy, Henry K. Gee,
Philip S. Moravcik, Gordon L. Dugan
August 1989

ABSTRACT
High-rate groundwater replenishment by irrigation with primary chlorinated effluent from the Honouliuli Wastewater Treatment Plant was tested in a 3-yr demonstration project for the Ewa limestone aquifer, O’ahu. Among the six options tested with different combinations of crops, 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 borderflood irrigated intermittently at an average rate of 20 in./wk. For this option, the production of 1 mgd of recharge water requires a 14.6-acre plot. For all options, recharge through 3 ft of vegetated, fairly permeable soil overlying 30 ft of permeable, reef limestone rock stabilized groundwater chlorides to 245 mg/l, stripped virtually all effluent nitrogen, and inactivated effluent bacteria. Toxics analyzed (pesticides, solvents, and heavy metals) were all below action or detectable levels. The natural system, which acts as a “living filter”, outperformed secondary treatment in improving the water quality. No adverse environmental effects were identified: no surface runoff, no insects, and no groundwater contamination. Except for slight clogging in the California grass plots toward the end of each harvest cycle, surface soil clogging was not evident. Plots were free of shallow standing water except for a few hours on the day of 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 plume spread in the aquifer several hundred feet from the site after the irrigation phase of a California-grass growth cycle. Project results favor a large scale water reclamation facility which will upgrade the Honouliuli primary effluent to a quality suitable for subsequent reuse.


Technical Report No. 183
GROUNDWATER FLOW AND DEVELOPMENT ALTERNATIVES: A Numerical Simulation of Laura, Majuro Atoll, Marshall Islands

John E. Griggs and Frank L. Peterson
June 1989

ABSTRACT
The numerical simulation of groundwater flow with solute transport is described for Laura on Majuro Atoll, Marshall Islands. The primary objective was to investigate strategies for developing and managing the freshwater resource in Laura. Secondary objectives included performing a sensitivity analysis of the parameters used to calibrate the model and illustrating the effect of density-dependent fluid flow. The two-dimensional mathematical model SUTRA was selected for the simulations because it is based on density-dependent fluid flow and solute transport equations. Cartesian coordinates were used to approximate a vertical cross section through the Laura area in which three boreholes and three nests of piezometers were emplaced during another 1987 study. The wells are along a line perpendicular to the ocean and lagoon shorelines running through the central portion of Laura. The model was calibrated in a transient mode with constant sea-level boundary conditions by using observed salinity data. Permeabilities and dispersivities were adjusted during calibration. In a preliminary attempt, tidal boundary conditions were also used to calibrate the model. Model calibration showed that the 50% isochlor depth depends primarily on permeability and that the transition zone thickness is most sensitive to transverse dispersivity. Simulated pumping results indicated that gallery-type wells constructed in the center of the islet could supply 1.4 to 2.1 million l/day of fresh water. Also, a comparison between flow regimes generated by single-phase fluid flow and density-dependent fluid flow demonstrated that the latter greatly affects the groundwater flow regime and must be included in flow dynamics modeling studies of atolls and small oceanic islands.


Technical Report No. 184
WITHDRAWN FROM PUBLICATION

Technical Report No. 185
AQUIFER IDENTIFICATION AND CLASSIFICATION FOR MAUI: Groundwater Protection Strategy for Hawaii

John F. Mink and L. Stephen Lau
February 1990

ABSTRACT
In response to the need to identify and describe aquifers for each island of the state of Hawaii to serve as a framework for groundwater protection strategy, a program has been initiated to classify and assign codes to the principal aquifers of the State. This second report provides Aquifer Codes and Status Codes for the island of Maui. The Aquifer Codes incorporate locational and descriptive indices, while the Status codes indicate the developability, utility, quality, uniqueness, and vulnerability to contamination of the groundwater resources. The codes were generated for Hawaiian conditions of groundwater occurrence and behavior in preference to using the DRASTIC approach suggested by the U.S. EPA.
Each Aquifer Type within an Aquifer System is assigned an Aquifer Code consisting of an eight-digit number. An Aquifer Code is unique and non-repeatable in the State. Accompanying the Aquifer Code is a Status Code of five digits. A Status code is specific to an Aquifer Code. The Maul classification includes 6 Aquifer Sectors, 25 Aquifer Systems, and 113 Aquifer Codes.


Technical Report No. 186
AQUIFER IDENTIFICATION AND CLASSIFICATION FOR KAUA’I: Groundwater Protection Strategy for Hawaii

John F. Mink and L. Stephen Lau
September 1992

ABSTRACT
In response to the need to identify and describe aquifers for each island of the state of Hawaii to serve as a framework for groundwater protection strategy, a program has been initiated to classify and assign codes to the principal aquifers of the state. This third report provides Aquifer Codes and Status Codes for the island of Kaua’i. The Aquifer Codes incorporate locational and descriptive indices, while the Status codes indicate the developability, utility, quality, uniqueness, and vulnerability to contamination of the goundwater resources. The codes were generated for Hawaiian conditions of goundwater occurrence and behavior in preference to using the DRASTIC approach suggested by the U.S. EPA. Each Aquifer Type within an Aquifer System is assigned an Aquifer Code consisting of an eight-digit number. An Aquifer Code is unique and non-repeatable in the state. Accompanying the Aquifer Code is a Status Code of five digits. A Status code is specific to an Aquifer Code. The Kaua’i classification includes 3 Aquifer Sectors, 13 Aquifer Systems, and 77 Aquifer Codes.


Technical Report No. 187
AQUIFER IDENTIFICATION AND CLASSIFICATION FOR MOLOKA’I: Groundwater Protection Strategy for Hawaii

John F. Mink, L. Stephen Lau
October 1992

ABSTRACT
In response to the need to identify and describe aquifers for each island of the state of Hawaii to serve as a framework for groundwater protection strategy, a program has been initiated to classify and assign codes to the principal aquifers of the state. This fourth report provides Aquifer Codes and Status Codes for the island of Moloka’i.
The Aquifer Codes incorporate locational and descriptive indices, while the Status Codes indicate the developability, utility, quality, uniqueness, and vulnerability to contamination of the groundwater resources. The codes were generated for Hawaiian conditions of groundwater occurrence and behavior in preference to using the DRASTIC approach suggested by the U.S. EPA.
Each Aquifer Type within an Aquifer System is assigned an Aquifer Code consisting of an eight-digit number. An Aquifer Code is unique and non-repeatable in the State. Accompanying the Aquifer Code is a Status Code of five digits. A Status Code is specific to an Aquifer Code. The Moloka’i classification includes 4 Aquifer Sectors, 16 Aquifer Systems, and 40 Aquifer Codes.


Technical Report No. 188
FIVE-YEAR REVIEW OF STATE LAND USE DISTRICTS: PROTECTION OF WATERSHEDS AND WATER RESOURCES IN HAWAII

Steven R. Spengler, Frank L. Peterson, John F. Mink
January 1992


Technical Report No. 189
GEOLOGY AND HYDROGEOLOGY OF THE ISLAND OF POHNPEI, FEDERATED STATES OF MICRONESIA

John F. Mink, E.T. Murabayashi, L. Stephen Lau
January 1992

ABSTRACT
The island of Pohnpei is the eroded remnant of a large shield volcano that was built up from the surrounding sea floor by the repeated eruption of mildly alkalic lava. The main island is composed entirely of volcanic material erupted episodically over the last 9 million yr. The volcanic construction of Pohnpei can be divided into three stages of activity. The first was a shieldbuilding phase dominated by the frequent eruption of alkali olivine basalt, which was followed after an eruptive hiatus of roughly 1.5 million yr by sporadic volcanic activity dominated by basanitic and hawaiitic composition lavas (Awak volcanic stage). Shortly after the end of the shield-building stage, a large-scale landslide event is postulated to have removed much of the northwestern portion of the original shield volcano. The final stage of volcanic activity (Kupwuriso volcanic stage) produced voluminous flows of undersaturated lavas, which blanketed much of the southern half of the island. The thick, massive, low-permeability postshield-building lavas of the Awak and Kupwuriso volcanic stages dominate the present-day geomorphology and hydrogeology of the island.
Due to regional subsidence and sea-level rise (roughly 5.5 m over the last 6,000 yr), Pohnpei lacks extensive coastal plains of sedimentary material around its perimeter. Instead, volcanic rock and fringing mangrove swamps occur along the coastline around much of the island.
Rainfall on the island is abundant year-round and ranges from 400 cm/yr along the coastline to an estimated high of 900 cm/yr in the island’s interior. A high runoff-rainfall ratio (0.67) is estimated for the island’s river basins. An evapotranspiration rate of 140 cm/yr is estimated for the island. These values lead to an estimated islandwide groundwater recharge of 600 to 750 million liters per day.
Groundwater development on Pohnpei has been limited mainly to areas in the northern part of the island in and around the town of Kolonia and Palikir, the new Federated States of Micronesia capitol site. Wells in the Kolonia area exploit local unconformities between flow units of the late-stage volcanics and the unconformity between these volcanics and the underlying shield-building lavas. Somewhat more productive wells located in the Palikir area exploit relatively unweathered shield-building lavas. Groundwater development in the northern half of the island is hindered by the low permeability of the basement rock and by the lack of an extensive, low permeability capping layer to impede the movement of basal groundwater out into the lagoon. More favorable conditions for the development of basal groundwater are thought to exist in the southern half of the island due to the presence of relatively thick deposits of low-permeability ash near the coast, although groundwater has not yet been developed there.


Technical Report No. 190
AQUIFER IDENTIFICATION AND CLASSIFICATION FOR LANA’I: Groundwater Protection Strategy for Hawaii

John F. Mink, L. Stephen Lau
April 1993

ABSTRACT
In response to the need to identify and describe aquifers for each island of the state of Hawaii to serve as a framework for groundwater protection strategy, a program was initiated’ to classify and assign codes to the principal aquifers of the state. This fifth report provides Aquifer Codes and Status Codes for the island of Lanai.
The Aquifer Codes incorporate locational and descriptive indices, whereas the Status Codes indicate the developability, utility, quality, uniqueness, and vulnerability to contamination of the groundwater resources. The codes were generated for Hawaiian conditions of groundwater occurrence and behavior in preference to using the DRASTIC approach suggested by the U.S. Environmental Protection Agency.
Each Aquifer Type within an Aquifer System is assigned an Aquifer Code consisting of an eight-digit number. An Aquifer Code is unique and non-repeatable in the State. Accompanying the Aquifer Code is a Status Code of five digits. A Status Code is specific to an Aquifer Code. The Lana’i classification includes 4 Aquifer Sectors, 9 Aquifer Systems, and 22 Aquifer Codes.


Technical Report No. 191
AQUIFER IDENTIFICATION AND CLASSIFICATION FOR THE ISLAND OF HAWAII: Groundwater Protection Strategy for Hawaii

John F. Mink, L. Stephen Lau
May 1993

ABSTRACT
In response to the need to identify and describe aquifers for each island of the state of Hawaii to serve as a framework for groundwater protection strategy, a program was initiated to classify and assign codes to the principal aquifers of the state. This sixth report provides Aquifer Codes and Status Codes for the island of Hawaii.
The Aquifer Codes incorporate locational and descriptive indices, whereas the Status Codes indicate the developability, utility, quality, uniqueness, and vulnerability to contamination of the groundwater resources. The codes were generated for Hawaiian conditions of groundwater occurrence and behavior in preference to using the DRASTIC approach suggested by the U.S. Environmental Protection Agency.
Each Aquifer Type within an Aquifer System is assigned an Aquifer Code consisting of an eight-digit number. An Aquifer Code is unique and non-repeatable in the State. Accompanying the Aquifer Code is a Status Code of five digits. A Status Code is specific to an Aquifer Code. The Hawaii classification includes 9 Aquifer Sectors, 24 Aquifer Systems, and 68 Aquifer Codes.