Cosumnes Coalition Partners and Collaborators work together to obtain and share current scientific information to guide restoration, reconciliation and stewardship efforts.  A comprehensive science program includes consideration of water quality, hydrology, groundwater (geohydrology), water supply, land use, cultural resources, economy, connectivity, and ecosystems.  Understanding of each element and how they interact is necessary to support adaptive management decisions, leading to a healthy watershed that can support both humans and native ecosystems.

Cosumnes 1, 2 and 3:  UC Davis Center for Watershed Science and the Cosumnes Preserve Partners

UC Davis (and more recently UC Merced and UC Water) have worked with the Cosumnes Preserve Partners  for many years to study hydrogeomorphic conditions and aquatic biology of the Lower Cosumnes River.  The work has included: upper watershed hydrologic modeling; lower watershed groundwater hydrology; geomorphology of the floodplain; biogeochemistry and nutrient cycling in aquatic and floodplain habitats; ecology of fish and aquatic invertebrate communities, riparian bird surveys; and analysis of the reestablishment of riparian forests, among other topics.  More information may be found at:

Cosumnes Preserve Partners' history, assessments and plan may be found at:

Oneto Denier Flood Plain Restoration

Photo Courtesy of

The Nature Conservancy

Salmon Escapement Monitoring

The Fishery Foundation has monitored Cosumnes salmon escapement and out migration for over a decade, creating an important record that may be correlated with weather and passage barrier removal.  USFWS has provided important support of Fishery Foundation monitoring in 2017.

With passage barrier removal complete in 2011, and high rainfall amounts in 2016, the 2016/2017 salmon run has recorded 1247 salmon!

Cosumnes Coalition

Water Quality Monitoring Program

The ARC Cosumnes River Monitoring Program is CEDEN compliant and approved by Water Resources.  The Program is made possible by the Cosumnes Coalition contributors and Citizen Scientist volunteers, whose generous donations and dedicated efforts make it possible to gather and analyze water quality data, identify trends, and monitor project outcomes.  The Program was transitioned from Trout Unlimited to ARC in 2017, to support upcoming projects.

Clickhere for 2015 Monitoring Report

Clickhere for 2016 Monitoring Report

Omochumne Hartnell Water District (OHWD) Off Season Irrigation Groundwater Monitoring Study

Cosumnes Coalition is collaborating with OHWD, Larry Walker and Associates, UC Water, iWEST/Sac State, The Nature Conservancy, the Water Forum, and the Sacramento County Water Agency to monitor groundwater movement in real time during OHWD's groundwater recharge efforts, as well as perform chemical analysis, in 2018. 

Watershed Assessment

The Cosumnes Coalition recently completed the 2016 Cosumnes River Watershed Update and Stewardship Plan (2016 Plan), which builds on the extensive conservation and stewardship investment made by a variety of agencies and organizations in the upper and lower watersheds, linking upper and lower watershed approaches in one document.  Click here to open the 2016 Plan.