Circulation of the Latest Riverwalk Habitat Survey Data

Results from the 2017 Santa Ana Riverwalk, which was conducted on October 25, 2017, have been uploaded into the annually updated Riverwalk Atlas. The Atlas provides a map-based summary of the data collected during the annual survey event.

The data reflected in the Atlas has been gathered since the initial Riverwalk that occurred in 2006. That year the first group of Santa Ana Sucker Fish Conservation Team members, local volunteers, U.S. Fish & Wildlife Service (USFWS), California Department of Fish & Wildlife and Santa Ana Watershed Project Authority (SAWPA) staff volunteered their time and resources to document the quality of aquatic habitat in the Santa Ana River.

Post-Riverwalk-Twitter-Post

The primary purpose of the Riverwalk is to survey the status of the Santa Ana sucker fish’s habitat. The Santa Ana sucker is primarily a bottom feeder so a river bottom with a mixture of sand, gravel and cobble is ideal for the algae that the fish feeds on. The sucker is listed as a threatened species by the USFWS under the Endangered Species Act of 1973. Conducting a regional survey is useful because the data gathered can be integrated with other habitat and fish surveys. It allows different entities, who may collect other data, to compare their data to the Riverwalk survey and track trends.

2017 was an important year to collect data along the River because it occurred after what many perceived as the end of the 2011 to 2016 California drought. Flow levels (expressed as daily mean discharges) at a US Geological Survey gaging station located in the Riverwalk survey area are provided below and show the relative increase in the winter of 2016-17 during the last California drought. To truly correlate sucker habitat and flows, further analysis would be needed that compares sucker habitat conditions to volume, timing, duration, magnitude and variability of flows in the River.

2014-2017 Flows at MWD

Several agencies in the watershed are working on models to project flow levels in the watershed, including the SAWPA administered Basin Monitoring Program Task Force and the Upper Santa Ana River Habitat Conservation Plan administered by San Bernardino Valley Municipal Water District (SBVMWD). Projections in surface flow were developed through another effort in 2013 led by SAWPA and the Bureau of Reclamation whereby they determined runoff potential at 36 points in the Santa Ana River Watershed using the Coupled Model Intercomparison Project and the Variable Infiltration Capacity hydrology model. These projections show changes in mean runoff (annual or seasonal) for three future decades – 2020s, 2050s and 2070s – from the reference 1990s decade based on recorded flows at the Prado Dam USGS gaging station. The 2050s and 2070s show a decrease in annual, winter, and spring runoff. Note that Seven Oaks Dam on the Santa Ana River was constructed in 2000, after the 1990 reference period.

USBR Runoff Projections at Prado

About the Santa Ana Sucker Conservation TeamSASCT-Logo

The Conservation Team, administered by SAWPA, conducts the Riverwalk each year. The Team uses the data collected from the Riverwalk to evaluate the condition of the fish habitat. Various projects and studies aimed at recovering the Santa Ana sucker are funded by the Santa Ana Sucker Conservation Team member agencies, which include Orange County Water District (OCWD) and the City of Riverside. SAWPA, with project partner OCWD who is providing environmental planning and monitoring support, is currently constructing a habitat project using rock, boulders and cobble within the Riverwalk survey area near the cities of Jurupa Valley and Riverside.

The project will provide beneficial habitat in a central part of the River. To provide the most benefit to other public agencies, the development of the habitat structure’s engineering plans are also being coordinated with other agencies such as SBVMWD to serve as a design template for their future habitat projects.

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SAWPA Consultant Nate Scheevel Assisting the U.S. Army Corps of Engineers on a Similar Habitat Project

A Volunteer Effort

Thanks to all the approximately forty volunteers who attended on October 25, 2017 to make the Riverwalk possible. If you want to learn more about the Santa Ana sucker, the work going into its recovery and meet staff and other volunteers involved in the world of water and natural resources management, we encourage you to participate in the 2018 Riverwalk. Please stay tuned this fall for an announcement of the event’s date. The announcement will be distributed through the SAWPA email distribution list. If you have any questions, contact Ian Achimore via email: iachimore at sawpa.org.