Combined Monitoring and Simulation of Groundwater Contribution to Streams in the Lake Mendocino Watershed
Abstract
Lake Mendocino is an important reservoir for both flood control and water supply in the Russian River watershed. The US Army Corps of Engineers (USACE) operates the lake according to a rule curve that dictates water levels depending on the time of year. The lake is operated to maximize flood protection, with water supply and power generation as ancillary benefits to the project. In an effort to maximize benefits without reducing flood protection the USACE Engineer Research and Development Center is studying the application of physics-based hydrologic modeling forced with forecasted precipitation generated by the Scripps Institute of Oceanography West WRF model. As part of this research effort streamflow, rainfall, hydro-meteorological, and radioisotope data were collected from October 2017 to April 2018 from six smaller streams in the watershed. The radioisotope data are being used to separate the rainfall and overland flow from the groundwater component of streamflow. Understanding the mixture of surface water and groundwater in streams during a range of conditions helps us to better understand, simulate, and, potentially, manage Lake Mendocino. The Gridded Surface Subsurface Hydrologic (GSSHA) model is being used to simulate coupled surface water/groundwater flow in the Lake Mendocino basin. The streams being sampled were considered inconsequential at the larger watershed scale, and were not initially included in the Lake Mendocino watershed model. In order to assess the impact of the smaller streams on the watershed hydrology we built a coupled surface water/groundwater GSSHA model of Cold Creek, one of the small monitored streams in the larger Lake Mendocino watershed model. This inset model was used to analyze factors that may influence groundwater contribution to the stream flow, such as stream density. We compared the simulated volumes of flow from the different components, surface and groundwater, to the amounts determined through the hydrograph separation analysis from the field data. In this presentation we present the results of this analysis of the Cold Creek basin as well as discuss impacts on the larger Lake Mendocino watershed model.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.H31L2101D
- Keywords:
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- 1804 Catchment;
- HYDROLOGYDE: 1839 Hydrologic scaling;
- HYDROLOGYDE: 1847 Modeling;
- HYDROLOGYDE: 1879 Watershed;
- HYDROLOGY