TU’s Conservation Hydrology program has built the largest non-governmental stream gage system in California
At its core, Trout Unlimited’s restoration work is dedicated to improving flow, water quality and stream connectivity for trout and salmon.
In the West, this effort is accomplished largely by working in partnership with landowners, agricultural operators and water agencies. Those partnerships improve dry season streamflows and update state water laws to allow willing water rights holders to dedicate a portion of their right to keeping more water instream when fish need it most.
TU’s California Water Program has taken this mission to the next level by building and monitoring an extensive system of stream gages across the North Coast and Central Coast regions. This is done to better inform conservation actions and water rights management in the recovery of native coho salmon and steelhead. This work is sourced in the science arm of the California Water program—the Conservation Hydrology project.
A major milestone reached
Recently, the team passed a major milestone with the installation of the 100th stream gage in its statewide monitoring network. The network aims to gather the high-quality, long-term hydrological data needed to better understand and protect the habitat requirements of California’s salmon and steelhead. Seven more stream gage installations quickly followed. The team’s stream gage system is now the largest non-governmental gage network in the state.
This milestone is especially impressive given that the “ConHydro” team is comprised of only seven staff, led by Mia Van Docto, who directs the California Water Program; Krysia Skorko, who manages the program’s gage network in the Sierra Nevada; and Troy Cameron, who manages data collection in the program’s monitoring network in 22 watersheds across 250 miles of California coast, from Santa Cruz to Mendocino County.
How and where ConHydro works
When TU launched the program nine years ago, the team operated 25 gages, primarily within two coastal watersheds—the Navarro and Russian Rivers.
The geography of the ConHydro system has since expanded inland to encompass alpine meadows throughout the Sierra. While some of these gage sites are easily accessed by decent roads, others are in remote backcountry areas and fieldwork may require pack mule teams to carry essential gear.
This stream gage system is monitored and maintained through a schedule of monthly field visits, during which ConHydro technicians measure streamflow, stream depth and water temperature and record photo documentation of sites. Additional data metrics may include riffle crest thalweg (the line or curve of lowest elevation within a valley or watercourse) depths, dissolved oxygen concentrations, surface water mapping and juvenile salmonid distribution.
The Conservation Hydrology program also monitors 81 groundwater wells.
Putting the data into action
Altogether, this data helps inform management decisions aimed at improving habitat conditions and enhancing the long-term survival of native salmonid species, particularly juvenile coho salmon and steelhead trout during the critical summer months when flows are lowest and streams may become disconnected.
Many of ConHydro’s stream gages are paired with TU restoration project sites to validate the streamflow benefits of restoration. A good example is a project on Flynn Creek, in the Navarro River Watershed. At this site, TU’s North Coast Coho Project (NCCP) is piloting a “gully-stuffing” technique that will increase winter recharge capacity and boost summer baseflows. The Conservation Hydrology team supports this work by monitoring and quantifying changes in both ground and surface water conditions.
The work of the Conservation Hydrology program depends on the support of and collaboration with numerous partners, including:
- California Wildlife Conservation Board
- The Nature Conservancy
- California Sea Grant
- California State Parks
- NOAA Fisheries
- California Department of Fish and Wildlife
- Sonoma Resource Conservation District
- Mendocino County Resource Conservation District
- Gold Ridge Resource Conservation District
- San Mateo Resource Conservation District
- private landowners
- other organizations and individuals
TU’s decades-long commitment to enhancing dry season flows in vital salmon, trout and steelhead streams in California is now supported by millions of dollars in investments. The extensive Conservation Hydrology stream gage system plays a key role in monitoring the effectiveness of these investments and in guiding recovery of salmonid populations across the state.