Guam Hydrologic Survey Program
Dr. Nathan Habana, Operations Manager
Funded by the Government of Guam
The Guam Hydrologic Survey (GHS) and the Comprehensive Water Monitoring Program (CWMP) were created in 1998 by the 24th Guam Legislature’s enactment of Public Laws No. 24-247 and 24-161 respectively. WERI was charged with administering the annual legislative appropriations necessary to drive these two programs and facilitate, direct and implement their primary objectives. Both programs are now an integral component of the WERI water resources research, information dissemination, education and training mission.
The purpose of GHS is to consolidate Guam’s hydrological data gathered over the years by local and federal government agencies and consultants, and to conduct research on water related issues of local importance. GHS also funds a variety of water resource educational programs in various formats, including guest lectures and seminars at UOG and in the community, informational and training workshops for teachers and professionals from other government agencies, field trips and talks for schoolchildren, and the publication and distribution of educational posters, maps, and fact sheets.
The CWMP was created to collect data on saltwater intrusion and water lens thickness in Guam’s sole source aquifer in the northern part of the island and stream flow and other parameters associated with surface waters in the south. The program rehabilitated data collections assets that had fallen into disrepair. In 1998 the CWMP appropriations from the Guam Legislature restored the Federal/State-Territory cost-sharing program for water resource monitoring and reinvigorated the collaborative work between WERI and USGS.
The foresight of the Guam Legislature in creating these two very important programs deserves special mention here. Through their efforts and continued support, we have consolidated and interpreted several vital water resources databases for Guam and revitalized the USGS water resources monitoring program. Our understanding of the complex physical, chemical and biological processes that influence Guam’s water resources has broadened considerably and the increase in graduate student research opportunities provided by the programs has substantially added to the number of highly trained water resources professionals in the island’s work force.
GHS and CWMP Program Management Organization
One-Guam Groundwater Resources Development Group and Technical Experts Group
Program Activities for FY 2021
Research Projects
Outreach
GHS and CWMP Program Management Organization
WERI organizes and integrates the GHS and CWMP programs to manage and execute the public law. The WERI personnel organizational chart of duties and responsibilities are shown below. WERI’S groundwater hydrologist is the program manager, supported by research advisors of hydrogeologist, meteorologist, toxicologist, and GIS expert. The research affiliate reports to the program manager and is supported by a CWMP research assistant and digital assistant. Program manager has a digital assistant for the GHS website and a graduate research assistant for groundwater model research.
One-Guam Groundwater Resources Development Group and Technical Experts Group
WERI is also a member of the local water resource interagency organization called the Technical Experts Group (TEG) and the Groundwater Resource Development Group (GWRDG), created in the December 2016 MOU. The GHS and CWMP mandate require interagency collaboration and cooperation, as written, “establish a direct working relationship with each organization collecting hydrologic data important to Guam and maintain a permanent flow of new data from each organization to keep the data library up to date.” Attending local government and federal agencies are Guam Waterworks Authority, Guam Environmental Protection Agency, Consolidated Commission on Utilities (CCU), US Navy (NAVFAC, Marianas), US Air Force (CES), and USGS. Our interagency groups also include private consultants: Duenas Camacho and Associates, Allied Pacific Environmental Consultant (APEC), EA Engineering, Brown and Caldwell, and AECOM. Meetings are organized and held quarterly at Guam Waterworks Authority (Gloria B. Nelson Public Service Building), Fadian. Current discussion is the expansion of monitoring (observation) wells, see details in Ongoing Research section.
Program Activities for FY 2021
The GHS program management, WERI Director, and Research Affiliate has reorganized the program management to include undergraduate research assistant support. The undergraduate research assistant’s slot to be filled will assist the program management, supporting web development as GHS mandate part of data repository, access, and distribution. The Research Affiliate will utilize an undergraduate research assistant to manage data and field assistance.
The Guam Hydrologic Survey office and computer hydro-laboratory at WERI had been remodeled to improve GHS functionality. Designated storage space and worktable has been built to organize and prepare valuable field equipment. Workstations and workspace have been configured properly for research assistants in the environmental science program. A Guam geologic rock display section was built to improve collection and organization of the island’s rock inventory. This area was also designed as a small geology laboratory.
GHS provides limited stipends for research by graduate students working on their MS degree in Environmental Science and partial summer salaries to WERI faculty advising those students. It also pays for undergraduate field and lab assistants working on water resources projects on Guam, and the salary of one full-time Research Affiliate is charged with operating and managing WERI’s information database, the hydrology laboratory, and preparation and update of routine reports and presentations.
Research Projects
Research projects are grouped into four sections: database, maps, sustainable management, and outreach. The database organizes a borehole database, which is the basis of subsurface information, and a water resources library. It also includes the collection and organization of pertinent meteoric, hydrologic, and water quality data. The maps often summarize the data analysis and are truly indispensable tools for water resource management. Sustainable management is a multi-faceted approach to quality sustainable water resource. The workshops provide training and outreach to our interagency partners.
Outreach
Guam Hydrologic Survey provides outreach programs. WERI teams up with Guam Waterworks Authority, Guam Water Kids, UOG Professional and International Programs, for the NGLA Executive Tour and Technical Workshops.
Comprehensive Water Monitoring Program
Dr. John Jenson, WERI & Dr. John Hoffman, USGS
Funded by USGS and the Government of Guam
The United States Geological Survey (USGS) has monitored our island’s water resources since 1951. Unfortunately, during the 1990s they were forced to downsize this program because matching support from the Government of Guam was discontinued. This resulted in the abandonment of all deep monitoring wells needed to monitor saltwater intrusion in the north, and most of the stream gages in the south by the mid-1990s. In 1995, the USGS closed its field office at Naval Station, but continued to run a limited monitoring program (out of its Saipan and Honolulu offices). In August, 1998 the Comprehensive Water Monitoring Program (CWMP) was made a permanent part of WERI’s program when Governor Gutierrez signed PL 24-161. This resulted in the refurbishment of the deep monitoring wells and a renewed program of water resource monitoring on Guam. The intent of PL 24-161 was to restore, and then to expand, as needed, the discontinued monitoring program in order to help Guam manage and safeguard all of its freshwater resources, now and in the future. Under PL 24-161, WERI/UOG and the USGS entered into a memorandum of understanding to administer and fund this program on a cost-sharing basis. The CWMP is a permanent investment in Guam’s future.
A well-designed long-term CWMP can save communities millions of dollars, and even human lives, by providing critical information for water supply, culvert and bridge design, delineating flood-hazard areas, and tracking effects of climate change. The USGS started a water-resource monitoring program in Guam in 1951 with installation of stream gages at Pago, Lonfit, and Tolaeyuus and a rain gage near Fena dam. At the same time, measurements of discharge from Almagosa Springs and water levels in Fena Reservoir started. Since 1951 about 22 stream gages, 8 rain gages, and 16 groundwater-monitoring wells have been operated, providing reliable information on the water resources and hydrologic hazards of Guam.
Currently, USGS monitoring on Guam consists of 6 continuous-recording stream gages, 1 reservoir monitoring station, 8 continuous-recording groundwater-level-monitoring wells, 7 groundwater wells where the thickness of the freshwater lens is measured, and 8 continuous-recording rain gages. From a broad perspective, the program provides long-term information on the hydrologic cycle of Guam so that its water resources can be understood and sustainably managed. The bulk of the monitoring stations on Guam are funded as part of a Joint Funding Agreement between the USGS and WERI.
Stream Gages for Water Availability and Flood Planning in Southern Guam
Stream Gages for Water Availability and Flood Planning in Southern Guam
Most freshwater used in southern Guam comes either from streamflow or wells that withdraw water from near the banks of streams. Data from USGS stream gages provide information needed by managers and engineers to properly manage the long-term sustainability of these water resources. Statistical analyses of long-term streamflow data are needed so the effects of abnormally wet or dry years can be understood and planned for. For example, USGS gages provide information that can be used to assess and manage the sustainability of surface water from the GWA Ugum Treatment Plant. Other gages, funded in cooperation with the U.S. Navy, are used to manage withdrawals from Fena Reservoir.
Long-term streamflow information is needed for flood planning. This information is used to delineate flood zones, estimate the magnitude of floods and frequency with which they could be expected to occur, and design bridges and culverts. For example, information from 11 stream gages and 3 other sites was used to assess the flood-peak magnitude and recurrence interval following Typhoon Chata‘an in 2002. FEMA uses information from USGS stream gages to determine the level of financial aid from FEMA after storms. Currently, the WERI-USGS CWMP funds the operation of 3 stream gages at key locations in southern Guam.
Well Monitoring of the Northern Guam Lens Aquifer
Well Monitoring of the Northern Guam Lens Aquifer
Monitoring wells operated as part of the USGS-WERI CWMP provide information to assess the health and sustainability of the Northern Guam Lens Aquifer. This aquifer is the most important source of freshwater on the island. Currently, the program includes 8 wells where water level is continuously measured and 7 wells where the thickness of the freshwater lens is measured biannually. Collectively, this information allows scientists at WERI, GEPA, GWA, and USGS to understand the flow of water through the aquifer and refine sustainability estimates of this resource. This information is used to understand how current withdrawal is affecting the aquifer and how future changes in climate and groundwater production may affect the sustainability of groundwater resources. Coupled with detailed geologic mapping and modern hydrologic tools such as groundwater flow models, information from this long-term program will be invaluable as additional water is needed to support increasing economic development on Guam.
Rainfall Data to Estimate Water Supply Recharge and Flood-Water Distribution
Rainfall Data to Estimate Water Supply Recharge and Flood-Water Distribution
The USGS currently operates 8 rain gages on Guam, 6 of which are funded by the WERI-USGS CWMP. Rainfall data are fundamental to understanding the water supply and threats from flooding. Information from these gages is used to evaluate the extent of drought during El Niño events and the severity of flooding during typhoons. Information from rain gages is also essential in determining how much freshwater infiltrates past the ground surface to reach the water table. This water, known as recharge, is the source of freshwater in the Northern Guam Lens Aquifer and only by measuring rainfall can its abundance be accurately estimated.
What Does It Cost to Operate Data Collection Instruments?
What does it cost to operate data collection instruments?
In fiscal year 2022, the cost to operate a continuous-record stream gage will be $24,515. This includes all operation and maintenance, site visits, field data collection, data analysis, and computation of the flow record. Gage operations are frequently reviewed and upgraded as improvements become available. Other gages, such as rainfall ($10,675) and groundwater ($7,725), require less funding. With over 100 years of experience, USGS procedures ensure that data are reliably collected, analyzed, and publicly available.
Most data from USGS gages are readily available on the internet. As part of CWMP between WERI and the USGS, historic data and other hydrologic information for Guam are consolidated and made publicly available at: http://hi.water.usgs.gov.
Completed Projects
Development of the Groundwater Model of the Yigo-Tumon Basin, Northern Guam Lens Aquifer
A Comprehensive Review and Consolidation of Unpublished WERI Research on the NGLA Response to Variations of Sea Level and Rainfall
A Sustainable Plan for Stormwater Management and Flooding at Garapan, Saipan
Hydrological Features and Analysis in the Finegayan Area
Establishing Groundwater Protection Zones in Guam
Aerial Survey and Field Instrumentation for Investigation of Landslide Threat to a Tropical Watershed in Southern Guam
Comprehensive Hydrological Database for Secure Water Resources in Tofol Watershed, Kosrae
Hydrological Control on Submarine Groundwater Flow in Ayuyu Cave
Development of the Groundwater Model of the Yigo-Tumon Basin, Northern Guam Lens Aquifer
Funded by USGS
MS Environmental Science Thesis
Guam has plans for major island growth and expansion well within the next 10 years, requiring more water from its principal source—the Northern Guam Lens Aquifer (NGLA). Developers will be looking for groundwater models to test aquifer capacity and placement of additional wells. Reliable groundwater models are very useful for determining aquifer development strategies that include optimum production well configuration and sustainable management of water resource. The Yigo-Tumon Basin, in the NGLA, is the most abundant source of utility water out of the 6 aquifer basins, where deep production wells extract about half of the total 42 MGD from the NGLA, which is about 90% of total water produced on the island. More than 20 years of NGLA research and data is available that can be used to develop a reliable groundwater model of the NGLA, starting with the Yigo-Tumon Basin. A new addition to NGLA research in 2019 is the time-series of phreatic profiles in three deep observation wells in this basin that present the spatially varied dynamic response to recharge, from which model results can be matched. And most recently accomplished, groundwater model assessment of the capacity of each basin’s “sweet spot,” the parabasal zone. Also, the advancement in groundwater modeling software and computer technology, integrating tested finite element code extensions (FEM Water), GIS capability, 3-D interface are available in Aquaveo® Groundwater Modeling Systems (GMS) that will be the selected model application, and that will run on WERI’s fast computer.
A Comprehensive Review and Consolidation of Unpublished WERI Research on the NGLA Response to Variations of Sea Level and Rainfall
Funded by USGS
Rainfall amounts on Guam are high. The average annual rainfall on the island is roughly 100 inches, with modest (10-15%) geographical variation (drier in the middle and on the central east coast, and wetter in the southern mountain region and in a stripe across the northern end). But, despite high average rainfall, there are large variations of rainfall at all time scales. Over the course of the year, there is typically a 6-month dry season during which only 30 inches of the annual 100 inches accrues. It is thought that very little of the dry season rainfall recharges the aquifer. The amount of annual rainfall also has large variation, primarily the result of forcing by the El Niño/Southern Oscillation (ENSO) phenomenon. Annual rainfall amounts vary by a factor of three! (50 to 150 inches). Daily rainfall during a typhoon exceeds 7 inches in one hour and 30 inches in 24 hours.
In past WERI research efforts, evidence was found that on top of the immediate response of the water table to rainfall and variations to sea level, the water table of the NGLA responded at an 18-month lag to long-term surpluses and deficits of rainfall. An elegant method, outlined in 2009 (minimizing the hysteresis of modeled water table with respect to the observed water table), elucidated the response of the aquifer to rainfall input. The findings of this research were largely exploratory, with formal investigative follow-through pending. This project will consolidate and summarize these past findings with a formal rigor (data consolidation, updated data, further statistical analysis, clarification of the techniques, and a detailed discussion of the results).
A Sustainable Plan for Stormwater Management and Flooding at Garapan, Saipan
Funded by USGS
Flooding is an overflow of a large amount of water beyond its normal limits. Floods are the most common and widespread of all weather-related natural disasters. Floods in the U.S. kill more people each year than other natural disasters. Average annual flood damages in the U.S. are more than 2.2 billion dollars a year. Furthermore, increasing trends in number of these natural disaster have been observed. Today flooding control including stormwater management has become a critical issue in civil and environmental engineering applications.
Stormwater management is originally intended for flood control and minimal water quality improvement. With stormwater runoff, four major problems begin to emerge; Flooding: excess stormwater increases the extent, severity, and frequency of floods. Degraded water quality: stormwater carries a number of pollutants, nutrients, pathogens, and floating matters on streets. Erosion: increased stream volume and velocity exacerbate streambank erosion. Sewer overflows: increasing stormwater volumes contribute to combined sewer overflows.
Floods are a common occurrence in the lower Garapan area, Saipan. The relatively flat terrain in the target area causes lack of gradient, which prevents adequate drainage and the lack of drainage outlets. Thus, severe ponding problems are emerged from following moderate and heavy rainfalls. A flood prone zone includes an extensive number of residential structures, stores, and commercial establishments. Especially, the most critical area is located between the hotel resort area and the West Coast Highway. Due to frequent flooding over the area, it can be expected that the following offshore water quality, which caused by erosion and sewer overflows, and flooding damages. The objectives of the proposed project can be summarized as the followings;
1) To collect relevant base data, maps, aerial imagery;
2) To identify stormwater runoff flowing characteristics;
3) To develop stormwater management model;
4) To suggest the Low Impact Development (LID);
5) To simulate the stormwater model for current and future weather conditions.
Hydrological Features and Analysis in the Finegayan Area
Funded by USGS
Guam Waterworks Authority (GWA) is the custodian of Guam’s public water supply and is responsible for ensuring that it meets all appropriate standards as mandated under the Safe Drinking Water Act and Clean Water Act of US EPA. To this end, GWA regularly evaluates the physical, chemical and biological integrity of the island’s drinking water in accordance with US EPA requirements. While the agency has maintained a considerable amount of monitoring data over the years, only values that approach or exceed the water quality standards are paid attention. The rest, which account for well over 99% of all monitoring data collected so far, falls well below critical thresholds of concern and is of little immediate interest or attention. As a consequence, these data are simply stored on file for reference purposes. They are just paid attention only when they need be used to identify subtle changes in contaminant abundances and distributions within the aquifer or changes for a long-term basis.
Because of projected increase of population, and relocation of around 5000 marines from Okinawa to Gaum in the next few years, water quantity and quality, particularly groundwater quantity and quality will be crucial to the sustainable development of resources and environment in Guam. Since the Finegayan area will be involved in lots of buildup activities due to relocation of marines, it’s very important to evaluate whether the related activities will affect the quantity and quality of the water resources, especially groundwater resources. Concerning water quality problems in the northern Guam lens aquifer (NGLA), salinity is of serious consideration. Based on this concern, the project will focus on salinity problem in Finegayan. The foci of the project will aim to evaluate the patterns of salinity levels from individual wells and all wells in the basin in space and over time, and to analyze the trends of salinity change of individual wells and overall trends of salinity in the basin spatially and temporally.
Establishing Groundwater Protection Zones in Guam
Funded by USGS
Guam is the largest (about 541.3 km2) and southernmost member of the Mariana Islands chain. It currently supports a local population of around 170,000 and receives over 1.5 million tourists annually. The relocation of around 5000 marines and their dependents in the next few years, and foreign labors hired to assist with buildup activities will impose impacts on water quantity and water quality in Guam.
Groundwater from a karst limestone aquifer in the northern Guam supplies local residents and tourists with approximately 90% of their daily water needs. While estimates of the aquifer’s sustainable water resources remain adequate for the current population, there is serious concern that the projected population increase will severely compromise the island’s drinking water supplies and have an unprecedented impact on water quality and quantity. The high porosity and rapid recharge characteristics of the northern Guam lens aquifer make it vulnerable to contamination from urban runoff, chemical spills, effluents from septic tanks and sewage overflows.
Guam Waterworks Authority (GWA) is in charge of Guam’s public water supply and ensures that it meets all appropriate standards as mandated under the Safe Drinking Water Act and Clean Water Act. While the agency has collected a considerable amount of monitoring data over the years, only values that approach or exceed the water quality standards are paid attention. Most of the data fall well below critical thresholds of concern and is paid little attention. However, these data may be useful for evaluation of changes of contaminants for a long-term basis.
Since groundwater in the Northern Guam Lens Aquifer (NGLA) supplies local residents and tourists with about 90% daily water use, it’s absolutely necessary to set up groundwater protection zones (GPZs) and make sure that water quality can be maintained so that the daily life of the people of the island will not be affected. The main purpose of the project will focus on a better way to create GPZs, particularly GPZs located in the parabasal zone in the NGLA. The existing GPZ boundary lines have been made available from the Guam Environmental Protection Agency (GEPA) for WERI to utilize and update.
Aerial Survey and Field Instrumentation for Investigation of Landslide Threat to a Tropical Watershed in Southern Guam
Dr. John Jenson, & Dr. Shahram Khosrowpanah
Funded by GHS
During 2019, the research team reviewed different watersheds in southern Guam and after much deliberation have identified 2 locations in Inarajan watershed, 2 locations along hillslopes of Fena Valley reservoir, and one location along Nimitz Hill Ridge in Piti-Asan watershed for this study. The PI and his research team has made several field visits to these sites and collected soil samples for lab studies as well as performed aerial and terrestrial photographic surveys to map the slope failures in these locations. One undergraduate engineering student from UOG’s school of engineering has been hired on part-time basis to assist in lab testing and field assistance.
This research includes a one plus-year field monitoring study and will be followed by analyses of field data which will serve as an input of soil properties for slope stability analyses. Field instrumentation has been installed at Ija research station site in August 2019 and will be soon installed at Fena site. It will allow measuring the near-surface hydrologic response to assess the potential for landslides that mobilize into debris flow. It is our intent to capture a live shallow landslide event during monitoring period which will allow for identifying the triggering mechanism and modeling the safety factor changes. Shallow slope failure analyses will be presented and conclusions along with recommendations will be made to prevent future slope failures. Although we earlier planned monitoring of spatiotemporal soil surface movement along the slopes, later with consultation with the Co-PI’s we decided to not include this part and instead we included more site locations for field and lab studies. In next phase, we request to provide us with a budget to buy subscription to remote services to access data and for numerical analyses software for slope stability studies and purchase some supplementary field supplies. These measurements will be a valuable information which will enable us to hopefully capture “real time slope failure”.
Comprehensive Hydrological Database for Secure Water Resources in Tofol Watershed, Kosrae
Funded by USGS
The management and allocation of water resources have always been considered as one of the most significant endeavors in human society since water plays a vital role in all natural and environmental systems of the Earth. Information on the variability in time and space of rainfall and on the resulting runoff characteristics is thus essential for the planning, design, and water resources management. For instance, daily/monthly precipitation time series are commonly used for the assessment of the available water resources in a region, and the extreme rainfall amount for a given return period is required for the estimation of flood for the design of hydraulic structures.
However, almost all river basins on the Federated States of Micronesia (FSM) do not have a network of rainfall and flow measurements to provide a sufficient record of observed data, estimating accurate hydrological responses. Rainfall records have been collected by various governments since 1985. Due to short or incomplete records, it is however impossible to be used for estimating the available water resources on the island. Consequently, characterizing watersheds on the island for the sustainable water supply was identified as a high priority concern at the Advisory Council Meeting for the FSM held in Kosrae Island in October 2019.
The water collected from surface water sources generally requires heavy treatment processes to reduce its turbidity, remove micro-organisms, and odor. Nevertheless, there is no one who was trained on water quality testing and sampling with not enough facilities. In addition, the Advisory Council Meeting 2019 requested a training course on ArcGIS for the development planning. To maintain the monitoring system consecutively and to test water quality at local sites, it has been recognized as a high priority work to conduct training courses. The proposed courses will cover the water quality test, the maintenance of the monitor systems, and to implement GIS data. They fall within the category of Research and Education/Professional Training Needs for the FSM, respectively. The operators for the measurement instruments do not require official certification, but training can be done by an instructor.
The immediate objectives of this phase are to set up the monitoring systems for daily rainfalls and stream flows on the island and to train personnel. The following works cover gathering the measured records and storing them for the public purposes. Building a database and/or website will be required for continuously providing the water resources information. From the information provided by this project, further research works will be suggested for the development of duration curve, the development of average and low flow, and the wastewater treatment plant design.
Hydrological Control on Submarine Groundwater Flow in Ayuyu Cave
Funded by NASA EPSCoR
MS Environmental Science Thesis
Characterizing karst features is integral to understanding groundwater flow in karst aquifers. A USGS modeling study (Gingerich, 2013) of withdrawal and drought in the Northern Guam Lens Aquifer (NGLA) indicated that discharge was especially concentrated at Finegayan Basin on the northwest coast. Previous coastline projects observed a channel of freshwater discharge at a single cave, Ayuyu Cave, which measured 2.3 MGD. This cave is hypothesized to be located at the end of the Pugua Fault, an important geologic feature with potential to channel groundwater in Finegayan Basin.
Observations of the cave interior revealed three sections: an enlarged chamber filled with tidal debris (trash, shell and coral fragments, and cave rubble), inner passages filled with detached cave formations from the walls and ceiling, and a brecciated zone with varying-sized conglomerate limestone bedrock pieces. The most significant finding was an unexplored passageway that led to a cave pool. Water samples indicate the pool is in the brackish zone of the lens (386 mg/L chloride). Water level loggers currently are logging temperature and pressure in the cave pool and in the chamber the pool is located. These project aims to conduct an updated cave survey and produce a digital map of these new cave areas in 2D and 3D. Additional surveys need to be conducted on the fault surface to characterize the position of Ayuyu Cave relative to the Pugua Fault. Fundamental project goals are to 1) further understand the geologic processes by which coastal karst aquifers transmit and discharge groundwater and 2) improve existing models of groundwater storage and flow for coastal and island karst aquifers.
Ongoing Research
Groundwater Model of the Machanao Basin, Northern Guam Lens Aquifer
Surface Hydrology of the Northern Guam Lens Aquifer, Phase II
Information Transfer of Water Quality Analysis Techniques for FSM Water Utility Agencies
PFOS Trend Monitoring in Saipan Production Wells
In-situ Characterization of Extreme Rainfall on Guam, FSM and the CNMI
Establishing Groundwater Protection Zones in Guam, Phase II
Spatial-Temporal Analysis of Patterns and Trends of Salinity in Yigo-Tumon Basin
Phase II - A Sustainable Plan for Stormwater Management and Flooding at Garapan, Saipan
A Comprehensive Review of Hydrogeological Assessments of Sinkholes on NGLA, Guam
Northern Guam Lens Aquifer Monitoring System Expansion Rehabilitation Program (MSERP)
Identifying, Analyzing and Mapping Submarine Groundwater Discharge (SGD) with a Thermal Infrared (TIR) Sensor and Unmanned Aerial Vehicle (UAV)
Potential PFAS Contamination Sites Near the GWA Production Well A-25
Groundwater Model of the Machanao Basin, Northern Guam Lens Aquifer
Funded by USGS
Guam is undergoing major military development and expansion that may require up to 11 MGD more water beyond the current 40-44 MGD from its principal source—the Northern Guam Lens Aquifer (NGLA). The large USMC Camp Blaz complex, new under construction, straddles two of the NGLA’s six groundwater basins: Finegayan and Machanao. Plans call for additional production wells on Camp Blaz to provide another 2-4 MGD beyond the current 1 MGD production.
An ongoing groundwater model development project of one of the other basins, the Yigo-Tumon Basin, will serve as the pilot study for the Machanao Basin model. Machanao Basin has limited data on lens profiles, from only a single deep observation well (EX-8), but construction of two new deep observation wells in the Machanao Basin is underway. The model will simulate alternative scenarios of performance of new production wells planned for the basal zone. The groundwater model development will continue to use Aquaveo, LLC, Groundwater Modeling Systems (GMS) employed for the Yigo-Tumon model.
Surface Hydrology of the Northern Guam Lens Aquifer, Phase II
Funded by USGS
Recent engineering studies and Phase I of this project have revealed that the island karst surface of the Northern Guam Lens Aquifer is a self-organized system composed of a hierarchy of basins with tributary watersheds connected by overflow runoff paths, which cascade to a central, focal watershed. Phase I performed hydrologic spatial analysis on LiDAR based DEMs, producing a map that reveals the fundamental surface hydrology boundaries and runoff paths of the entire NGLA. Phase II analysis will result in a complete and thorough analysis of the surface hydrology to provide larger-scale details, such as tributary watershed divides, focal watersheds, and details within DEM fill areas. The product will be used to educate and assist local engineers, planners, developers, and regulators to better understand the nature of surface water movement and infiltration and thus to design, facilitate, and promote more effective and efficient storm water disposal while also managing risks of sediment occlusion of sinkholes and ponding basins, and contamination of drinking water via sinkhole infiltration.
Information Transfer of Water Quality Analysis Techniques for FSM Water Utility Agencies
Funded by USGS
Water quality is a severe issue for all utility agencies throughout the Western Pacific. The development of modern water treatment systems and distribution networks for some of the more populated islands in this area started in the 1970s. In the United States, the Environmental Protection Agency (EPA) regulates over 90 contaminants under the Safe Drinking Water Act (SDWA). Under the SDWA, regulate contaminants including microorganisms, disinfectants, disinfection byproducts, inorganic chemicals, organic chemicals, and radionuclides. These contaminants are regulated under the standards called “maximum contaminant levels (MCLs)” that present a risk to human health. Information transfer of water quality-related knowledge will benefit the FSM water agencies in further developing water quality analysis skills. The training of water quality technicians will also assist in acquiring advanced techniques.
PFOS Trend Monitoring in Saipan Production Wells
Funded by USGS
Saipan is a 19km long and 9km wide island located in the western Pacific Ocean and is the largest of the Northern Mariana Islands. Groundwater is a main freshwater source, and over 50% of production wells are located in the vicinity of the Saipan International Airport (SIA). The Airport Rescue Firefighting Facility (ARFF) at the SIA is suspected as a major PFOS contamination area and a main source for groundwater contamination. The public water and utility agency in Saipan has collected water samples from 24 drinking water entry points; 5 entry points were found to contain PFOS. These entry points include reservoirs and production wells in Isley Field and Koblerville where villages are located around the SIA. The main concerns of PFAS contamination in Saipan are 1) drinking water sources are limited, 2) pathways of PFASs contaminant transport have not been well identified, and 3) an independent ability to measure PFASs is lacking. This research will help to identify PFOS migration patterns in groundwater and establish a proper remediation plan.
In-situ Characterization of Extreme Rainfall on Guam, FSM and the CNMI
Funded by USGS
Rainfall and other climate data are required for studies of water quantity and water quality (WQ2) in our region. With the obvious importance of rainfall data, other climatic data with possible influence on WQ2 include (but are not limited to): the typhoon distribution; local and regional sea level; the MAX and MIN temperature, and the effects of wind and amount of sunshine. The project PI is constantly being asked to provide climate data for a wide array of WQ2 efforts, such as the recent EPA-sponsored GWUDI study, and a host of USGS-sponsored projects. A common request to the project PI by local water resource managers (and outside environmental consulting businesses) involves acquiring storm data to assess return-period calculations for storm drain projects, stream-flow estimates, reservoir management, etc. Acquiring climate data for such projects is hampered by the multiplicity of sources, incomplete or missing data in official records, short periods of record, and an absence of metadata on recording sites. Most of the region’s extremes of rainfall occur during typhoons, and there are very few in-situ measurements of short-term rain rates (e.g., 1-minute and 1-hour) and the storm totals. The causes of major damage (large waves, flooding and extreme wind gusts) often go unseen during the storms (for example, the case of the fuel tank fires at the Guam commercial port during Typhoon Pongsona that commenced unobserved at the height of the storm, with theories later abounding on the cause—lightning, metal-on-metal sparks, voltage surges in power, etc.). Similarly, extraordinary bridge-destroying flooding, and huge waves that whitewash miles of coastline to 40-foot elevations go unseen during the full rage of the storm; this is often compounded by darkness.
This proposal seeks to initiate a rapid response mechanism for observing the nature of extreme events. A simple package of instruments—time-lapse cameras, stream level loggers, and rain gauges—to be emplaced in areas of expected impact from extreme events. This could include a permanent set-up at locations with frequent exposure to natural hazards (e.g. the Umatac River Bridge), or a package of basic instrumentation (a rain gauge and a level logger) that could be set-up on short notice in advance of an expected extreme event.
Establishing Groundwater Protection Zones in Guam, Phase II
Funded by USGS
Guam is the largest of the Mariana Islands. It currently has 170,000 residents and prior to the pandemic hosted over 1.5 million tourists annually. In the next few years, growth driven by expansion of its defense installations will impose increased demand on freshwater resources and additional challenges for stormwater management, groundwater protection, and wastewater treatment and disposal. The high porosity and rapid recharge characteristics of the northern Guam lens aquifer make it vulnerable to contamination from urban runoff, chemical spills, effluents from septic tanks and sewage overflows. This project will lay the foundation for a systematic regulatory approach to accommodate the conditions and meet the needs described above by developing a series of maps of the relevant features. These maps will then be overlain to determine the types of risks associated with definable geographic sectors, and the appropriate risk management regulations and mitigation procedures for the various types of sector.
Spatial-Temporal Analysis of Patterns and Trends of Salinity in Yigo-Tumon Basin
Funded by USGS
Guam is the largest (541.3 km2) and southernmost member of the Mariana Islands chain. It currently supports a local population of around 170,000 and more than 1.5 million tourists annually. About 5000 marines will be relocated to Guam from Okinawa in the next few years. With the marines and their families moving to Guam, and the importation of foreign labor to assist with the buildup activities and infrastructure needs of the military, the island’s population is expected to grow substantially in the next few years. Groundwater from a karst limestone aquifer in the northern Guam plateau—the Northern Guam Lens Aquifer (NGLA)—currently supplies permanent residents and visitors with 90% of their daily water needs. While estimates of the aquifer’s sustainable water resources remain adequate for the current population, there is concern that meeting the projected population increase could compromise the island’s drinking water supply.
Phase II - A Sustainable Plan for Stormwater Management and Flooding at Garapan, Saipan
Funded by USGS
Floods are a common occurrence in the lower Garapan area, Saipan. The relatively flat terrain prevents adequate drainage and precludes drainage outlets. Severe ponding follows moderate and heavy rainfalls. The flood-prone zone includes an extensive number of residential structures, stores, and commercial establishments. The most critical area is between the hotel resort area and the West Coast Highway. The previous phase of this sustainable stormwater management project focused on collecting relevant base data, maps, digital elevation models (DEMs). The main objectives of the second phase project are To conduct onsite frequency analysis and regional frequency analyses; To identify the scale-invariant properties of annual extreme rainfalls; To develop a scale-invariant model based on Generalized Extreme Value (GEV) distribution for estimating sub-daily extreme rainfalls using daily historical records.
Comprehensive Review of Hydrogeological Assessments of Sinkholes on NGLA, Guam
Dr. Yong Sang Kim, & Dr. Nathan Habana
Funded by USGS
The Northern Guam Lens Aquifer (NGLA) supplies 90% of Guam’s drinking water. With steady population growth and military facilities relocating to Guam during the next decade, groundwater withdrawals from the NGLA are programmed to increase in the decade ahead. Ongoing new construction and steady urbanization pose new risks and challenges for stormwater disposal and groundwater protection. The karst surface is drained by sinkholes, which serve as natural ponding basins. Stormwater can carry pathogens, contaminants, debris, and sediments into sinkholes. Debris and sediment can block drainage from them, reducing their capacity for stormwater disposal. Pathogens and other contaminants that get into sinkholes can be transmitted rapidly to the groundwater. The general objective of this project is to gather and systematize the current knowledge and lessons learned from recent and ongoing hydrogeological assessments and engineering studies of sinkholes and storm drainage on the surface of the NGLA. This study will be complementary to a parallel project to build high-resolution maps of the surface drainage system. The report from this study will describe and explain what has been learned and documented about certain major features shown on the maps. The final product will thus be useful for hydrogeological assessment studies by public and private water resources professionals responsible for either stormwater management or groundwater protection.
Northern Guam Lens Aquifer Monitoring System Expansion Rehabilitation Program (MSERP)
Funded by Guam Waterworks Authority
The NGLA Monitoring System Expansion Rehabilitation Project (MSERP) launched on October 2017. This scope of work is divided into two tasks. Task 1 consists of (1) developing well-construction specifications for seven new deep-monitor wells and rehabilitating 12 existing monitor wells; and (2) defining sustainment requirements for the OEA-funded NGLA Monitoring System Expansion Project and associated expansion of the Guam Comprehensive Water Monitoring Program. Task 2 consists of geophysical logging of the seven new deep-monitor wells to evaluate aquifer properties, especially the characteristics of the water-bearing zones penetrated by the wells.
The Rehabilitation Phase of MSERP is near completion. Well fences, concrete pads, and deteriorated surface casings were removed. New PVC well casings were coupled a few feet below the ground surface to the existing casings that were still in good, usable condition. A wellhead locking cap, new well pad, well enclosure, and where needed, security fencing was installed. Bollards were installed at wells that required protection from passing vehicles. The surrounding grounds were cleared to maintain easy access at each well site.
The Expansion Phase of MSERP will include USGS and WERI working with GWA’s the Program Management Office (PMO) to provide technical support, including on-site support, before, during, and after construction of the new deep-monitor wells. The PMO will be responsible for ensuring that the driller constructs the wells as designed in the specifications and that the required timelines are met.
Identifying, Analyzing and Mapping Submarine Groundwater Discharge (SGD) with a Thermal Infrared (TIR) Sensor and Unmanned Aerial Vehicle (UAV)
Funded by NASA EPSCoR
MS Environmental Science Thesis
An autonomous aerial vehicle improved with a visual-thermal infrared gimble camera will be used to locate and quantify the plumes of freshwater discharging from the Northern Guam Lens Aquifer (NGLA), a sole-source karst limestone aquifer that comprises the northern half of the island and supplies over 90% of the island’s drinking water. The Guam-based research team has already found and mapped numerous seeps and springs with discharges that can be evaluated to test the technology and the university’s graduate environmental science program provides the human intellectual infrastructure of faculty and students who can conduct year-round fieldwork as well as laboratory analyses of GIS/remotely-sensed products and integrate the proposed work with previous and ongoing hydrological and spatial analytical studies. Quantifying the aquifer’s discharge provides a means of back-calculating its recharge, which comprises the limit to sustainable development for the island’s groundwater – the overriding question for water resource managers in any jurisdiction.
Besides proving the application of this new technology, this project will also build regional technical capacity for water resource management using UAVs and remote sensors and help local natural resource managers in Pacific islands build more detailed and useful geospatial datasets of geographic conditions affecting water resources. Specifically, it will make the application of the technology (through separately-funded related projects) available to the Federated States of Micronesia (FSM), which still have little useful geospatial data by which to manage their water resources. It will also expand the nascent Geography Program at UOG and put in place a local system to monitor geospatial data and manage natural resources using regular UAS flights and data collection. Finally, beyond these terrestrial applications, the NGLA provides a terrestrial analogue to help NASA in their studies of karst landscapes and processes on other planets.
Thermal images were first acquired in the summer, when tide was the lowest-low (-1 ft) and weather was optimal for operating the UAV. For comparison, images were captured during sunny days in the rainy season.
Potential PFAS Contamination Sites Near the GWA Production Well A-25
Funded by NIEHS and USGS
MS Environmental Science Thesis
Perfluoroalkyl substances (PFAS) have recently received attention as emerging contaminants in drinking water. Recent UCMR3 results reveal three Guam Waterworks Authority production wells to be contaminated with perfluorooctanesulfonic acid (PFOS). One of these wells (NAS-1) is located inside of the former Naval Air Station at Tiyan, in the village of Barrigada. PFOS concentrations found in this well to date range from 67-110 ng/L. The two other wells (A-23 and A-25) are located in Hagatña, one of the oldest villages on Guam. PFOS concentrations determined in both of these wells to date are consistently above 70 ng/L with maximum levels occasionally exceeding 400 ng/L in well A-25. Both wells are currently off-line. Ongoing PFOS source studies have so far identified four potential contamination sites based on historical records and favorable hydrogeological properties of the surrounding area.
These sites include: 1) a defective wastewater pump station that leaked millions of gallons of wastewater into the Chaot River over a 25-year period, 2) Agana swamp which drains the Chaot River and where chronic illegal dumping has occurred since WWII, 3) neighboring ponding basins that direct stormwater into the underlying aquifer, and 4) a nearby air flight crash site.
The objective of this study is to conduct a preliminary assessment of PFAS contamination sites in Hagatna and Ordot-Chalan Pago regions.
Education and Outreach
Digital Atlas of Chuuk - A Geospatial Map and Data Server for Resource Management
Guam Hydrologic Survey Website:
Power Web MApps
Workshop Series on Guam Groundwater Resources
Sand Filtration Training for Yap State Public Service Corporation (YSPSC)
Guam Water Kids
Advisory Council Meetings
Workshop Series on Guam Groundwater Resources
Dr. Yong Sang Kim & Dr. Nathan Habana
Funded by USGS and GHS
The military buildup and ongoing economic growth anticipated on Guam over the next decade have raised concerns regarding sustainable management of Guam’s groundwater resources. Besides educating policymakers and agency heads, it is essential that island water resource professionals and educators be equipped with an accurate and up-to-date understanding of the island’s aquifer and the factors that must be considered to frame and implement sustainable management practices. Professional people in the water resources industry, from technicians to engineers, managers, agency heads, and policy-makers have extremely limited time to engage in professional development education opportunities. In FY 2019, WERI offered a two-day professional workshop on the Northern Guam Lens Aquifer (NGLA). It was held on 31 January and 7 February 2020. The affiliations of the participant included Guam EPA, Guam Bureau of Statistics and Plans, and private firms including EA Engineering, GHD, APDI, and AECOM.
The workshop covered WERI’s aquifer database containing hydrogeological, engineering, and management data. The salinity histories of wells and the relations to well operation, construction, and location were also addressed. The workshop also introduced ongoing studies of salinity, PFOS, and nitrogen analyses, hydrologic modeling of groundwater production capacity, and concepts for sustainable management of the NGLA. Nine WERI faculty taught a total of nine sessions of the workshop. Four one-day professional tours of the NGLA were planned in FY2019, but the tours were cancelled due to the COVID-19 pandemic.
Sand Filtration Training for Yap State Public Service Corporation (YSPSC)
Dr. Myeong-Ho Yeo & Ken Rekdahl
Funded by USGS
There are four independent water authorities in Yap: FSM-Yap State Public Service Corporation (YSPSC), Map Municipality Water Authority, Gagil-Tamil Water Authority, and Southern Water Authority. This four-day training incorporated in-class lectures and hands-on practice sessions as well as field trips. This training was the first training in which the different water authorities participated together. Operators from three water authorities, agents from Environmental Protection Agency (EPA), and the agents from the Project Management Office, Yap State, attended this training. Although the original training objective was to have been only slow sand filtration, participants advised the trainer that YSPSC has a rapid water treatment system, and asked for instruction and advice on basic hydraulics, techniques, and equipment operation. The trainer therefore adjusted the curriculum to provide information and tools appropriate for current local conditions and resources.
The training thus included the following information and more: 1) introduction to water system hydraulics, from water sources to storage tanks to customers; the parts of pumps and how best to operate and maintain them; and 3) how to operate and maintain disinfection systems. This spontaneous course of instruction was very well received, and now is in constant demand. The success of the training is explicitly documented in the survey collected at the end: 69% marked it excellent, and 16% scored it very good. Regarding how applicable the training is to their work, 58% of the attendees said very applicable, and 21%, applicable. A certificate of the completion was given to each attendee and was uniformly highly appreciated.
Guam Water Kids
Kaylyn Bautista & Dr. John Jenson
Funded by USGS
This year’s Guam Water Kids program continued to build on the success of this well-received collaborative effort between WERI and K-12 educators in the local community. Activities included 1) a Guam Water Kids service-learning collaboration with two Guam Department of Education (GDOE) central district schools: Tiyan High School and P.C. Lujan Elementary School; and 2) presentations and activities at the Pay-Less (groceries stores) Summer Camp and University of Guam’s 52nd Charter Day community outreach events. The primary goal achieved this year was building the partnership between officials and educators from GDOE, Tiyan, and P.C. Lujan Elementary School to implement the Guam Water Kids service-learning modules. Representatives from both schools acknowledged the limited off-the-shelf resources and materials available to help visualize local geology, hydrology, and pollution sources in their classrooms. Teachers welcomed the program’s assistance to motivate students to be productive citizens and good stewards of the environment. Timely communication and logistic deliberate logistical planning aided in the Tiyan-P.C. Lujan service learning success in October 2019, despite Super Typhoon Hagibis’ passage over Guam the day before.
One notable success from this event is the quality of retention young students developed from the presentation of concise scientific explanations of local natural features and from subsequent hands-on activities. Several fifth-graders astounded the Tiyan High School ambassadors when they consistently
answered content questions during the service learning visit. These students were also summer school participants received instruction over a span of three months—from a July summer presentation to the service-learning presentation in October. WERI and Guam Water Kids are preparing training kits for educators and students using local rocks, gravels, and sands.
Guam Water Kids plans to expand its videos, free downloadable handouts and activities collection to include new footage from around the island.
Educational information for students can be found in the forms of narrated videos, flash cards, quizzes, and a link to the Guam Water Kids Facebook site for up-to-date media posts and announcements (https://www.facebook.com/guamwaterkids/).
Advisory Council Meetings
Dr. John Jenson
Funded by USGS
WERI’s Three Advisory Councils. WERI maintains a separate advisory council for each of its three regional constituencies: 1) the US Territory of Guam, 2) the Federated States of Micronesia (FSM), and 3) the Commonwealth of the Northern Mariana Islands (CNMI).
Each council is built around a core of officials, managers, and technical experts from local agencies involved with water resources development, management, or regulation, who serve as more or less permanent members. Some have been formally appointed by their governments or agency heads. Others serve by invitation from WERI. The composition and appointment process for each council reflects the governmental and geographic conditions unique to each constituency.
The Guam Advisory Council core members include managers and technical experts from local agencies, and local offices of US federal agencies, including the local military civil engineering units and their contractors that deal with water resources. The core members of the councils for the CNMI and FSM include representatives from local government departments, as well as permanently-stationed employees of US federal agencies; United Nations, European Union and other international development aid agencies; Non-Governmental Organizations; and local colleges and schools.
WERI convened each council for a day-long virtual conference to review and update its agendas for research, information transfer, and educational projects. In addition to the core members, people invited to the meetings include government officials, private sector engineers and planners, educators, students, and other scientific and professional colleagues involved in ongoing projects and programs. The morning agenda includes presentations on recently completed projects and ongoing projects. Following lunch, there are plenary and focus-group discussions on critical needs, after which each participant fills out a survey regarding directions of ongoing projects and prospective future projects.
Meeting participants frequently observe that WERI Advisory Council meetings are the sole venue in which all of the water resources professionals on their island meet together in a single group. The meetings are thus valued as unique forums for professional information-sharing and networking. Throughout each year, WERI uses council mailing lists to provide updates and announcements for events of common interest, including WERI research presentations, professional workshops, and thesis defenses.
University of Guam Programs Supported by WERI
Environmental Science Graduate Program
School of Engineering
Environmental Science Graduate Program
The Environmental Science Program is designed to provide students with an appreciation of the interdisciplinary nature of environmental problems that exist in the world today and prepare them for professional employment, teaching, or advanced studies in diverse areas of environmental science, or related disciplines. The program also serves working professionals in local schools, government agencies and the private sector who are seeking career advancement and/or professional enrichment, e.g., educators, regulators, administrators and planners.
The interdisciplinary focus of the program is intended to train students to identify and understand environmental problems and exercise sound judgment in effecting their remediation. This is accomplished through a careful blend of core courses and electives in an integrated teaching-research approach. Students are required to conduct a research project and document their study in thesis form. They are encouraged to present their findings in a variety of forums (e.g., society meetings, conferences, workshops, seminars, peer-reviewed journals, technical reports, newsletters and the local newspaper). Students also have the option to serve out an internship with a local environmental or engineering firm, or an appropriate Government of Guam or Federal Government Agency. This permits them to gain professional problem-solving skills in the environmental arena. Students who graduate from the MS program can, therefore, reasonably expect to enter professional employment in a variety of areas in the public and private sectors where an understanding of the complex interdisciplinary scientific, social, and political dimensions posed by environmental problems is increasingly necessary.
The Environmental Science Program strives to promote educational and service projects within island communities of the Western Pacific and attract a broadly based group of scholars committed to seeking answers to the many environmental questions that are arising in developing island nations of the tropical Pacific Basin. Areas of faculty expertise center around three broad areas of concentration namely, biology-ecology, geosciences-engineering, and economics-management.
School of Engineering
The School of Engineering grew out of the Pre-engineering program, which was established in 1989 by WERI faculty, who taught it voluntarily. In 2013, a cooperative agreement was signed with the Universities of Iowa, Mapua Institute of Technology (Manila, Philippines) for student and faculty exchange. The courses offered by the program at UOG were accepted by these institutes.
On October 29, 2009, the President of the University of Guam expressed his vision for establishing a four-year accredited engineering degree program to help meet current and growing demand for engineering expertise in Guam’s private and public sectors. In August 2016, the UOG Board of Regents formally chartered the new School of Engineering and the President appointed Dr. Shahram Khosrowpanah, who was then Director of WERI, to lead the new school as Interim Dean.
