TitleICONS: Interconnected Surface Water in California’s Central Valley
Resource Author(s)
  • The Nature Conservancy
Year of Publication2021
Link to Report/
Full Description

Sustainable groundwater management in California requires an understanding of how groundwater pumping affects surface water features. Groundwater seeps into many river and lake beds in California, providing a steady source of cool clean water. This source of water is crucial for people and nature because it remains steady throughout the year even after the winter rains stop. Under the Sustainable Groundwater Management Act (SGMA),
interconnected surface water (ISW) is defined as “surface water that is hydraulically connected at any point by a continuous saturated zone to the underlying aquifer and the overlying surface water is not completely depleted” (Groundwater Sustainability Plan Emergency Regulations).

SGMA requires special treatment of ISW, but in many parts of the state, ISW is poorly understood. This dataset categories rivers and stream segments on the likelihood that they are ISW, using groundwater depth as a proxy to determine ISW. This data is available to view in an interactive online map at:

Topic Area(s)
  • Environment – Terrestrial and Riparian/Aquatic