Merced River Plan Implementation: East Yosemite Valley River Restoration
The East Yosemite Valley River Restoration Project will stabilize the banks of the Merced River in east Yosemite Valley and prevent further accelerated erosion and widening of the river by re-establishing natural topography and native vegetation in heavily eroded areas. The project will also enhance conditions for aquatic life by providing shade, structural habitat elements, and organic matter. The Merced River in Yosemite Valley widened an average of 27% in the period between 1919 and 1986. In some parts of east Yosemite Valley the river doubled in width. This accelerated erosion is closely related to heavy visitor use and loss of vegetation.
To halt bank erosion, National Park Service (NPS) crews will plant willow cuttings in the river channel and remove about 1,700 cu. yd. of riverbank rip-rap from key locations. Crews will integrate wood into the riverbanks and channel to facilitate revegetation, provide structure, decrease flow velocities, and capture river sediment to slowly rebuild the banks. Crews will place logs strategically to limit scour and promote accretion. Restoration actions will require the use of a high pressure water drill to plant willows and a hydraulic excavator to remove rip-rap.
NEPA compliance for this project was completed as part of the Merced Wild and Scenic Comprehensive Management Plan EIS process. This project was selected for implementation in the 2014 Record of Decision for the Merced River Plan/EIS (MRP). This project must adhere to mitigation and stipulations in the Final EIS/Record of Decision, the MRP programmatic agreement, and permit requirements.