Hydrological Sciences

the extend of modeling area (left) and its estimated hydraulic conductivity distribution (right)

‘Ike Wai: Securing Hawai‘i’s Water Future

Numerical modeling techniques for density-driven flow in coastal aquifers and its application to West Hawai‘i Area Aquifers in island of Hawai‘i.
ASPA-UHWRRC weather station, stream gauge, and monitoring well network instruments.

UH-ASPA Hydrologic Monitoring Network

Hydrologic datasets are essential for the design of sustainable water supply systems and the prediction or detection of acute threats to drinking water quality or availability. We developed a hydrologic monitoring network consisting of 21 instruments including weather stations, stream gauges, and monitoring well dataloggers on the Island of Tutuila, American Samoa.
Figure 1. Apparent groundwater ages in West Hawai‘i, Hawai‘i Island.  

Assessment of Groundwater Ages Using Radiocarbon and Chlorofluorocarbons in West Hawai‘i Aquifer Systems

A multi-tracer approach was used to determine the apparent groundwater ages in West Hawai‘i. Radiocarbon chlorofluorocarbons were used to date water over a range of ages. The results can be used to assess aquifer storage and travel times, which are important is understanding the hydrologic system and assessing groundwater sustainability.
Figure 1. Conceptual model for the Keauhou basal aquifer (KBA) illustrates various inflows and outflows, Hawai‘i Island.

Development and Multi-Process Calibration for the Keauhou Aquifer in West Hawai‘i

The study included developing and implementing a conceptual model for the Keauhou Aquifer site in West Hawai‘i, calibrating the model using available data to their fullest extent to constrain parameters, and applying the model for management through simulating various scenarios aimed at assessing the risk to aquatic resources.
Multi-process modeling, uncertainty analysis, and participation are the main components of an effective scientific evaluation of groundwater sustainability policy with the sphere number reflecting the increasing degree of integration (from Elshall et al. 2020).

Groundwater Sustainability: A Review of the Interactions Between Science and Policy

This study provides a systematic review of the concept of groundwater sustainability, and situates this concept within the calls from the hydrologic literature for more participatory and integrated approaches to water security
Groundwater simulation optimization results with spring discharge constrained at (a) 80%, (b) 60%, (c) 40% of pre-industrial discharge, and (d) estimated spring discharge-sustainable yield tradeoff curve.

Incorporating Historical Spring Discharge Protection Into Sustainable Groundwater Management: A Case Study From Pearl Harbor Aquifer, Hawai‘i

This research provides decision-makers in Hawai‘i with information regarding the trade-off between groundwater pumping and spring discharge, which is connected to multiple benefits, including historical and cultural values in line with codified state beneficial use protections.
Illustration of present day model calculated average-annual groundwater recharge at 20 m cell-size resolution. Inset map shows detail of 1) flow routing effects, seen as higher recharge squares at the bottom of drainage channels, 2) direct infiltration from leaking water lines, seen as linear zones of higher infiltration, and 3) MFR zones seen as larger patches of high- infiltration.

A Participatory and Model Based Approach to Assessing Groundwater Recharge Under Contemporary and Future Climate Scenarios: Tutuila, American Samoa

A water budget approach using the Soil Water-Balance-2 model was applied to Tutuila Island in American Samoa. We also assessed potential future change in recharge by substituting rainfall and temperature projections from dynamically downscaled climate global climate model predictions and possible future land-cover scenarios developed with local stakeholders.
UH WRRC Director Tom Giambelluca visits one of the weather stations within the Tutuila Hydrologic Monitoring Network.

ASPA-UHWRRC Integrated Groundwater Modeling Framework

This work presents a collaborative modeling framework developed by participants at the American Samoa Power Authority and at the University of Hawai‘i Water Resources Research Center. The framework includes modular components including collection and analysis of climatic and streamflow data and development of a water budget model and groundwater model.
Staff member from the American Samoa Coral Reef Advisory Group measuring streamflow to provide flow information used to calculate surface water nitrogen loading to the coastal zone.

Ridge to Reef Management Implications for the Development of an Open-Source Dissolved Inorganic Nitrogen Loading Model in American Samoa

We developed a dissolved inorganic nitrogen (DIN) loading model by integrating commonly available datasets within a geospatial modeling framework for Tutuila, American Samoa. The model integrated an open-source water budget model, water sampling results, and publicly available streamflow data to predict watershed-scale DIN loading to the island’s entire coastline.

Synthesis of the Physical and Socio-Political Aspects of Hydrological Research in the Páramo

The objective of this project is to synthesize the current status of knowledge regarding the effects of land cover and climate change on the hydrological functioning and linked social and economic outcomes in high elevation Andean páramo grasslands from Perú to Venezuela.