Habitat Evaluation Procedures (HEP) Report; Steigerwald Lake National Wildlife Refuge, Technical Report 2000-2001.

Abstract

Steigenvald Lake National Wildlife Refuge (NWR, refuge) was established as a result of the U. S. Army Corps of Engineers (COE) transferring ownership of the Stevenson tract located in the historic Steigerwald Lake site to the U.S. Fish and Wildlife Service (FWS, Service) for the mitigation of the fish and wildlife losses associated with the construction of a second powerhouse at the Bonneville Dam on the Columbia River and relocation of the town of North Bonneville (Public Law 98-396). The construction project was completed in 1983 and resulted in the loss of approximately 577 acres of habitat on the Washington shore of the Columbia River (USFWS, 1982). The COE determined that acquisition and development of the Steigenvald Lake area, along with other on-site project management actions, would meet their legal obligation to mitigate for these impacts (USCOE, 1985). Mitigation requirements included restoration and enhancement of this property to increase overall habitat diversity and productivity. From 1994 to 1999, 317 acres of additional lands, consisting of four tracts of contiguous land, were added to the original refuge with Bonneville Power Administration (BPA) funds provided through the Washington Wildlife Mitigation Agreement. These tracts comprised Straub (191 acres), James (90 acres), Burlington Northern (27 acres), and Bliss (9 acres). Refer to Figure 1. Under this Agreement, BPA budgeted $2,730,000 to the Service for 'the protection, mitigation, and enhancement of wildlife and wildlife habitat that was adversely affected by the construction of Federal hydroelectric dams on the Columbia River or its tributaries' in the state of Washington (BPA, 1993). Lands acquired for mitigation resulting from BPA actions are evaluated using the habitat evaluation procedures (HEP) methodology, which quantifies how many Habitat Units (HUs) are to be credited to BPA. HUs or credits gained lessen BPA's debt, which was formally tabulated in the Federal Columbia River Power System Loss Assessments and adopted as part of the Northwest Power Planning Council's Fish and Wildlife Program as a BPA obligation (BPA, 1994). Steigenvald Lake NWR is located in southwest Washington (Clark County), within the Columbia River Gorge National Scenic Area. Historically part of the Columbia River flood plain, the refuge area was disconnected from the river by a series of dikes constructed by the COE for flood control in 1966. An aerial photograph from 1948 portrays this area as an exceedingly complex mosaic of open water, wetlands, sloughs, willow and cottonwood stands, wet meadows, upland pastures, and agricultural fields, which once supported a large assemblage of fish and wildlife populations. Eliminating the threat of periodic inundation by the Columbia River allowed landowners to more completely convert the area into upland pasture and farmland through channelization and removal of standing water. Native pastures were 'improved' for grazing by the introduction of non-native fescues, orchard grass, ryegrass, and numerous clovers. Although efforts to drain the lake were not entirely successful, wetland values were still significantly reduced.