The Evaluation of Stormwater Runoff to Recharge Groundwater for Use at Fort Irwin, California

Abstract

The use of modeling tools to predict the amount of stormwater that is generated from impervious areas will be imperative for urban planners and developers in arid and semi-arid regions in the future. The National Training Center (NTC) in Fort Irwin, California is located within the Mojave Desert, a region that is increasingly water stressed. The Automated Geospatial Watershed Assessment (AGWA) tool is a GIS based modeling tool that can be used for water conservation planning. In the AGWA tool, there is a hydrologic model, KINEROS2, that has been developed and tested in a semi-arid environment. This model will be used to determine stormwater runoff volumes that are generated by observed rain events and to predict runoff for future storms. Because the NTC only gets three to four inches of rain per year, a scenario analysis using NOAA Precipitation Frequency Data Server data and historical observations will also be performed using the AGWA tool to gain an understanding of the differences in model parameterizations at the site. Within Fort Irwin, there is existing stormwater infrastructure that aids in the facilitation of infiltration. More specifically, the Sleepy Hollow neighborhood has implemented stormwater collection methods to keep runoff on site, and they consist of a stormwater detention basin, controlled release of flood waters, and a drywell to enhance infiltration locally. To monitor the detention basin, the installation of a compound v-notch weir, pressure transducers, a Barologger, weather station, and weighing bucket rain gage took place in November 2017, and has been monitoring the site since. Soil samples also were taken on site in order to characterize the hydrologic soil parameters for input into KINEROS2. This thesis summarizes the preliminary modeling results based on three observed rainfall events and assesses the differences in multiple soil and rainfall parameterizations and their impact on surface water modeling at Fort Irwin.