Sandy River Delta Habitat Restoration Project, Annual Report 2001.

Kelly, Virginia ; Dobson, Robin L.

United States. Bonneville Power Administration.

关键词: Aluminium;    Gramineae;    River Deltas;    Plants;    Habitat;   

DOI  :  10.2172/819779
RP-ID  :  DOE/BP-00005685-1
RP-ID  :  NONE
RP-ID  :  819779

美国|英语

来源: UNT Digital Library

【 摘 要 】

The Sandy River Delta is located at the confluence of the Sandy and Columbia Rivers, just east of Troutdale, Oregon. It comprises about 1,400 land acres north of Interstate 84, managed by the USDA Forest Service, and associated river banks managed by the Oregon Division of State Lands. Three islands, Gary, Flag and Catham, managed by Metro Greenspaces and the State of Oregon lie to the east, the Columbia River lies to the north and east, and the urbanized Portland metropolitan area lies to the west across the Sandy River. Sandy River Delta was historically a wooded, riparian wetland with components of ponds, sloughs, bottomland woodland, oak woodland, prairie, and low and high elevation floodplain. It has been greatly altered by past agricultural practices and the Columbia River hydropower system. Restoration of historic landscape components is a primary goal for this land. The Forest Service is currently focusing on restoration of riparian forest and wetlands. Restoration of open upland areas (meadow/prairie) would follow substantial completion of the riparian and wetland restoration. The Sandy River Delta is a former pasture infested with reed canary grass, blackberry and thistle. The limited over story is native riparian species such as cottonwood and ash. The shrub and herbaceous layers are almost entirely non-native, invasive species. Native species have a difficult time naturally regenerating in the thick, competing reed canary grass, Himalayan blackberry and thistle. A system of drainage ditches installed by past owners drains water from historic wetlands. The original channel of the Sandy River was diked in the 1930's, and the river diverted into the ''Little Sandy River''. The original Sandy River channel has subsequently filled in and largely become a slough. The FS acquired approximately 1,400 acres Sandy River Delta (SRD) in 1991 from Reynolds Aluminum (via the Trust for Public Lands). The Delta had been grazed for many years but shortly after FS acquisition grazing was terminated while a master plan and Environmental Impact Statement (EIS) were developed for the site. During the following three years, the vegetation changed dramatically as a result of cessation of grazing. The dramatic changes included the explosive increases of reed canary grass monocultures in wet areas and the expansion of Himalayan blackberries throughout the site.