PARENT SESSION
Oral Session #25: River and Riparian Restoration I.
Presiding: M.A. Madej
Tuesday, August 6. 8:00 AM to 11:30 AM. Mohave Meeting Room, TCC.
River restoration in Yosemite Valley, California: A case study.
DENN, C*,1, BEATTY, K1, FRITZKE, S1, ACREE, M1, GOLDMAN, V, 1 National Park Service - Yosemite National Park, El Portal, CA
ABSTRACT- Since the late nineteenth century, the Merced River channel in Yosemite Valley has been altered due to the development and use of campgrounds, roads, trails, lodging and bridges within the floodplain. Concentrated recreation activities and infrastructure along the riverbanks have contributed to accelerated bank erosion, channel widening, and isolated increases in bed depth. Between 1991 and 1996 the National Park Service in Yosemite recontoured and revegetated eleven high-use riverbank sites in Yosemite Valley. Impermeable soils were decompacted, riprap was removed, and banks were revegetated. Large woody debris was anchored within and adjacent to the river channel and some eroded banks were rebuilt using bioengineering techniques. Trampling was eliminated with fencing and signs. Photo and channel geometry monitoring of the sites indicate initial revegetation success and sediment deposition onto eroded banks. In-channel monitoring of substrate composition, pool frequency, algal standing crop, and large woody debris density document the successful effects of these restoration actions on the Merced River system.
KEY WORDS: restoration, riparian, bio-engineering