Methods and assumptions used in this impact analysis include the following:
Activities that cause substantial disturbance to soils and vegetation may adversely affect water quality and quantity, which adversely affects fisheries habitats.
Surface disturbances accelerate runoff and sediment delivery to stream channels, which alters streamflows and reduces habitat quality for fish that require clear water, moderated streamflows, and clean substrates.
Increased sedimentation adversely affects most fish species in the Planning Area. This analysis, therefore, focuses on the degree of surface disturbance anticipated under each alternative.
The potential for sedimentation of streams and rivers is minimized through using BMPs.
The health of fisheries in the Planning Area is directly related to the overall health and functional capabilities of riparian/wetland resources, which in turn reflect watershed health.
As riparian systems adjust in response to the removal of vegetation or changes in hydrologic conditions, the availability of habitats required to fulfill the life history requirements of fish populations is likely to be affected.