Fena Valley Reservoir watershed and water-balance model updates and expansion of watershed modeling to southern Guam

Abstract

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Water resources on Guam—Potential impacts of and adaptive response to climate change

“…Future streamflow and recharge estimates were generated from modeled climate variables (rainfall, air temperature, and evaporation) for Guam during 2080-99 that were also estimated as part of this study through downscaling of climate models. To estimate future streamflow in southern Guam and future FVR water levels, future rainfall and air temperature inputs are needed for the surface-water models (Rosa and Hay, 2017a;Marineau and Wright, 2015;Marineau and Wright, 2017). Future recharge to the NGLA was estimated through a soil-water balance model (Johnson, 2012) using estimated future-climate variables and was applied to the existing groundwater model (Gingerich, 2013).…”

“…Several models were used to evaluate Guam's water resources. In southern Guam, watershed and reservoir waterbalance models, published as part of this study (Rosa and Hay, 2017a), provided insight into the operation of the FVR. In northern Guam, an existing numerical groundwater model was available to evaluate how groundwater withdrawals affect salinity in the freshwater lens.…”

“…To estimate future monthly FVR water levels in response to various combinations of projected water-withdrawal rates, a two-step modeling procedure was developed, documented in Rosa and Hay (2017a) (fig. 3).…”

“…The second step uses streamflow estimates from the PRMS_2016 model simulations as input to a separate reservoir water-balance model (FVR_2016) to estimate changes in FVR water levels. Both models were developed using streamflow and climatological data from 1951-2015 (Rosa and Hay, 2017a). Details of the PRMS_2016 and FVR_2016 model development are available in Rosa and Hay (2017a).…”

“…Both models were developed using streamflow and climatological data from 1951-2015 (Rosa and Hay, 2017a). Details of the PRMS_2016 and FVR_2016 model development are available in Rosa and Hay (2017a).…”