University of California

Scott Valley

Journal Articles:

  • Foglia, L., J. Neuman, D.G. Tolley, S.B. Orloff, R.L. Snyder, and T. Harter, 2018. Modeling guides groundwater management in a basin with river-aquifer interactions. California Agriculture 72:1, 12 p.
  • Foglia, L., A. McNally, and T. Harter, 2013. Coupling a spatio-temporally distributed soil water budget with stream-depletion functions to inform stakeholder-driven management of groundwater-dependent ecosystems. Water Resour. Res. 49:7292-7310, doi:10.1002/wrcr.20555 (open access).

Reports and Online Webinars:



Principal Investigator:
Thomas Harter [contact for technical comments/questions]

The Scott Valley is an agricultural groundwater basin in Northern California, within the Scott River watershed and part of the much larger Klamath Basin watershed straddling the California-Oregon border.  The Scott River provides important habitat for salmonid fish, including spawning and rearing habitat for coho and fall-run Chinook salmon and steelhead trout. Sufficient flows at adequately low temperatures during summer, for rearing, and fall, for spawning, are critical for healthy fish habitat in the mainstem and tributaries.

The April 2013 Scott Valley Integrated Hydrologic Model data report presents the data assembled and the methods used for data analysis and data modeling to prepare the Scott Valley Integrated Hydrologic Model Version 2, which is currently under development. The report includes precipitation data analysis, streamflow data analysis and modeling, geology and groundwater data review and analysis, evapotranspiration and soils data analysis, and preparation of relevant watershed, land use, topography, and irrigation data. The data collection and analysis efforts culminate in the development of a spatio-temporally distributed soil water budget model for the Scott Valley. The soil water budget model is used to determine spatially and temporally varying groundwater pumping rates, surface water diversion rates, and groundwater recharge across the groundwater basin. The spatial resolution of the soil water budget model is by individual fields (land use polygons). Temporal discretization is in daily time steps for the period from October 1, 1990 to September 30, 2011. This period includes several dry years, average years, and wet year periods. Methods and results of the soil water budget model are presented in this report. This report represents the next step toward a better understanding of the interactions between groundwater, surface water, landuse, and agricultural practices with a specific focus on the seasonal impacts

Data, information, and analysis are needed through studies to understand the groundwater hydrology of the Scott River system and its relationship to surface hydrology, especially in areas where groundwater could affect Scott River water temperatures, potential riparian vegetation, and habitat connectivity for anadromous fish.  Without knowledge of the overall groundwater hydrology of Scott Valley, solutions to specific issues outlined in the TMDL Action Plan and the Scott River Groundwater Management and Enhancement Plan will not be possible.  It will be more cost effective to discover and prevent problems before they occur. Baseline data will be needed to determine the best approach in the design and implementation of water projects and water management alternatives and strategies to protect anadromous fish while also protecting the other beneficial uses, including the needs of agricultural operations.  Much of this information will need to be developed over a period of time necessary to have a sufficient record from which to discover and test feasible and effective management strategies.

The GW Study Plan and the Integrated Hydrologic Model are developed by the University of California at Davis (UC Davis) with the voluntary assistance of communities, landowners, the SRWC, the Groundwater Advisory Committee, and the Siskiyou Resource Conservation District (SRCD). The GW Study Plan is intended to be a living blueprint of the hydrologic, ecologic, water resource management, and agricultural management research needs and of the investigative approaches that can be taken to develop management practices that meet the mandate for protection of water, agricultural, and ecological resources in the Scott Valley. The GW Study Plan summarizes the current status of knowledge about the hydro-agro-eco-geography of the Scott Valley and outlines potential approaches to addressing critical current research needs. Individual study projects and tasks are described and scheduled in a way that is most efficient and timely to make the best use of funds to collect the information and data needed.



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