The goal of the interdisciplinary Willow Slough Watershed Study was to assess how carbon, nutrients, sediments and salts, are produced and transported in agricultural landscapes. Understanding the basic processes and identifying land management strategies for reducing water-quality concerns were at the core of the study. HydroFocus’ main focuses were groundwater-stream interactions and subsurface movement of nutrients, salts and carbon from agricultural fields to surface water. Our scope included collection of groundwater and unsaturated-zone physical and chemical data and development of groundwater flow and solute transport models.
In cooperation with the US Geological Survey and UC Davis-Department of Land, Air and Water Resources, HydroFocus, Inc. used integrated and quantitative analysis of physical and chemical data which provided new insights into watershed processes and directions for improved water and land management practices. HydroFocus used groundwater age-dating, isotopes of water and nitrate in groundwater and soils, hydrologic and temperature data and groundwater and heat-flow modeling. Our results indicate fertilizer inputs and denitrification in groundwater are major processes affecting groundwater nitrate concentrations.