Evaluating Aquatic Habitat Quality Using Channel Morphology and Multiscale-Scale Modeling Techniques

Fifteen streams in Northwestern Vermont spanning five geomorphic classes: stable, and unstable through change in planform, widening, aggrading, and degrading, (according to the Vermont Agency of Natural Resources Geomorphic Assessment (RGA) Protocols) were surveyed to assess the linkages between channel morphology and aquatic habitat quality. Detailed channel surveys were completed including cross sectional and longitudinal profiles, substrate samples, and Rapid Geomorphic Assessments. Habitat assessments included measures of substrate availability, embeddedness, presence of large woody debris and Rapid Habitat Assessments (RHA). Simple regression analysis of geomorphic parameters and habitat parameters shows that the RGA explains a significant amount of the variance in the RHA. In the second stage of this project, watershed-scale modeling was completed for each watershed using the Soil and Water Assessment Tool (SWAT). The model was calibrated and validated using gauged watersheds within the study region (Lake Champlain Basin). The model was used to generate stream hydrographs and basic watershed parameters (landuse summaries, runoff, sediment loading, etc.) for each watershed in the study. The model was executed for existing landuse and, in the future, will beused to predict impacts of landuse change. Watershed parameters were regressed with geomorphic and habitat condition to assess the ability of watershed-level characteristics to impact in-stream condition.