FY 2018 Suiattle River and Whitechuck River Side Channel Assessment

This project implemented phase 1 of a multi-phase project. In this initial phase, side channels were identified and data loggers were deployed.



USGS reviewed LIDAR imagery of the Sauk River basin including the Whitechuck and Suiattle Rivers taken in 2015. In 2017, we contracted Quantum Spatial to take thermal infrared imagery in the Sauk River basin to identify cold water patches. By using the lidar elevation data and digital color orthophotography, geomorphologic feature characteristics of side channels were identifiable.



We started monitoring by deploying data loggers at the upstream end of identified side channels to monitor water temperature and water level changes.

The purpose of this project is to identify side channel habitat in the Suiattle River and Whitechuck River. A second element deploys data loggers to monitor water temperature and water level changes in these side channels. Future phases of project will assess habitat suitability for Chinook and chum spawning; plus rearing, and refuge for all salmonid species. This initial project phase will provide a list of identified side channels sites for further investigation. At completion of all project phases candidate sites will be identified that would benefit from some restoration action. The deliverables would give us a list of sites to protect, enhance, and restore.



The project will provide a starting point to study stream channel complexity by identifying side channels in the Suiattle River and Whitechuck River floodplains. The Skagit Chinook Recovery Plan (SCRP) emphasizes the need to investigate stream channel complexity in the floodplain. The plan also identified floodplain isolation from the mainstem river due to disturbances from hydro modification. SCRP also suggest global warming impacts need to be assessed. Connectivity issues have been observed during summer low flows in recent years. Off channel habitat such as side channels provide spawning habitat opportunities, rearing space, and flood refuge. The Skagit Chinook Recovery Plan noted numerous studies observing high densities of Chinook parr rearing in these off channel habitats.