Certain areas of Steigerwald Lake NWR and Pierce NWR are seasonally flood irrigated to improve goose browse, control invasive species, and enhance wildlife production. However, the diverse and possibly conflicting needs of multiple species must be considered. Riparian areas on the refuges have been substantially altered from their historic condition as a result of cattle grazing, land clearing, stream diversions, levee construction and hydroelectric projects. Restoration of degraded riparian areas has included such actions as fencing out cattle, relocating roads, and planting buffer strips. Extreme fluctuations in water elevations resulting from operation of Bonneville Dam continue to cause bank erosion.
Similar impacts occur from wave action caused by traffic on the Columbia River.
Water temperatures are elevated in some stream reaches due to inadequate amounts of shade. Upland areas of the refuges support mixed coniferous and hardwood forests and grasslands. Historic land uses, especially logging and ranching, resulted in conversion of bottom land forest to pasture. These grasslands today consist primarily of introduced pasture grasses and exotics. The forest understory consists of native and non-native species.