Tuesday, September 27, 2016

Big Springs Ranch Salmon Restoration Project

In 2009 the Nature Conservancy (TNC) began an effort to restore the coho salmon populations in the Klamath basin with the Shasta Big Springs Ranch Project. The Klamath River was once a major salmon producing. Changes to Klamath River flows and habitat loss due to human activities and development in the last 150 years have caused declines in the salmon runs. The Shasta River is a tributary to the Klamath River and was historically a major salmon producing stream.  Shasta Big Springs Ranch, located in the upper portion of the watershed, is a critical area where springs maintain both flow and cool temperatures.  TNC acquired the ranch and adjacent lands several years ago with the aim of improving habitat for coho and Chinook salmon and steelhead trout.
Shasta Big Springs Ranch Study Site (Reference Note 1)
Land and water use changes through time have led to water temperatures in the  Shasta River basin that do not support all life stages of these cool water fishes.   Critical to salmon and steelhead survival are appropriate water temperatures for summer rearing and spring-time juvenile migration.

Big Springs Creek’s water source provides water in the 10C-12C temperature range year-round and has flow rates that seasonally range from 40 to 80 cfs. Therefore, to create and maintain a suitable habitat for the Salmon along Big Springs Creek and downstream of the creek, maintaining the flow and these lower water temperatures provided by Big Springs Creek is critical.

Elevated water temperatures on Big Springs Creek were caused by low water levels and lack of shade due to loss vegetation, and inflows of irrigation return water. In 2009 livestock were prevented from entering Big Springs Creek which caused an increase in the aquatic vegetation including extensive emergence vegetations. This added vegetation increased water depth (via flow resistance) and shade, both aided in reducing heating of the water in Big Springs Creek. The added vegetation also provided cover for juvenile salmon and formed a basis of the food web (primary production and invertebrate populations) that support young salmon.
Year-on-year temperature measurements from Big Springs Creek and nearby irrigation canal

TNC was targeting a living landscape approach the would support both instream flow and habitat as well as providing a means to support agricultural practices.  In 2010 Eyasco was contracted to install a network of wireless solar-powered monitoring stations that would collect temperature and flow data and display real-time data on a web site that could share the data with ranch managers and staff. 

Automated temperature and flow monitoring stations on Shasta Big Springs Creek
The concept was that ranch managers could observe water temperatures at multiple locations on the creek and in diversion canals and return flow facilities, and use this information to operate in a manner that would minimize temperature impacts due to irrigation return flow.  Differences between irrigation water in off-stream canals and the water in Big Springs Creek in real time were accessible to managers, allowing them to release water back into the creek when temperature differences were within acceptable limits.
Daily temperature swings in creek and canal
Before the Shasta Big Springs Ranch project, only 30-60 feet of Shasta Big Springs Ranch had suitable habitat for salmon. After the introduction of better management practices including real-time temperature monitoring suitable habitat was increased to 10 miles with an overall 7.2 degrees C drop in the water temperature during summer. Eyasco’s real time low-power monitoring system continues to provide critical data year-round information for ranch managers.

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