Reports

Report Number: 31
Year: 1981
 

Evaluation of the Groundwater Resources of the Agag Basin, Saipan

No abstract was published. A summary of the Introduction and Results follows.

The Agag groundwater basin has long been considered an important freshwater resource on Saipan. Development of this resource began in the early half of 1945, with the construction of eight wells through summer 1979. Apparently, encrustation of some of the older wells occurred, and it was easier to redrill them than purge and clean them. Four of these eight wells are still online, with a combined production of approximately 600,000 gallons per day. The others are used as observation wells only.

Prior to this study, little information was collected concerning the yield of the basin, its hydrogeologic properties, or its sustainable yield. After the construction of the eight wells, no follow-up data were collected, so the effects of pumping on groundwater flow conditions are unknown. After the three older wells were redrilled, a few pumping tests were performed and some data was collected on the behavior of the water table through spot measurements and continuous recordings. The depth of the saturated zone was estimated to be around 60 feet and local hydraulic conductivity to be about 25 ft/day. Unknown but necessary parameters included the type and location of basin boundaries, geologic characteristics of the aquifer, and the magnitude and seasonal characteristics of recharge to the system. Exploratory drilling revealed the hydrogeology and lithology of the aquifer, and water level monitoring illuminated the water table configuration and time response of the flow system. Available pump test data were analyzed using standard analytical techniques.

Author(s):
Jerry F. Ayers