The Pilchuck River is home to close to 1,000 riverside residents, several species of salmon, and countless other birds and animals. Ensuring a healthy, safe, and clean river for all can be a challenging task. Pilchuck riverside landowners have suffered damage from flooding and loss of property due to erosion in the past years, and salmon numbers have declined dramatically from historical levels. Three species of local salmon – Chinook, steelhead, and bull trout – are now listed as “threatened” on the Endangered Species List.
Snohomish County Surface Water Management has been studying these changing conditions in the Pilchuck River in order to better advise residents how to minimize flooding and erosion, while maintaining a healthy river for fish and wildlife.
The goals of the river assessment are:
- Assess the health of the Middle Pilchuck River;
- Identify projects that will address flooding and erosion concerns for landowners as well as improve fish habitat.
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of assessment area.
The assessment was conducted on the stretch of river that flows from the City of Snohomish Diversion dam on the upstream end to the OK Mill Road bridge at the downstream end.
What we did
The first step of this assessment was to document the current condition of the river.
Data was collected in summer 2010 and included:
- areas of recent bank erosion
- width and depth of the river channel
- sediment size and location
- frequency and depth of pools
- location and abundance of large woody debris jams
- condition of vegetation along the banks
- water temperature
This data, coupled with historic data on channel location and movement, enabled us to take a look at how sediment is moving through the system, what changes have occurred in the river, and where potential restoration opportunities would be feasible.
What the Assessment Revealed
The information we collected indicates the following actions will benefit landowners, fish and wildlife:
- Restore flow to side channels – to provide more space for flood waters, reduce the river’s impact on failing banks, and provide refuge for young salmon during winter flooding and high summer water temperatures.
- Plant vegetation along the river – to slow erosion and protect property, maintain cooler water temperatures, and provide protective cover and shade for fish.
- Add large wood to the river – to reduce erosion in vulnerable areas, and to create pools and cover for fish.
Conclusions from the study point to specific actions that can reduce flooding and erosion and simultaneously improve fish habitat. The County received funds from the Washington State Recreation and Conservation Office to design a limited number of projects within these identified priority areas. During January and February of 2012, we will be contacting landowners in these areas with an invitation to discuss project opportunities. Should we contact you, we hope you will be interested in talking with us about ways we can work together to make the Pilchuck River a healthier place for future generations of people and wildlife.