Correlation of hydrogeomorphic characteristics with runoff at Beichuan River basin in Qinghai province

Runoff observation data at 5 gauging stations were used to calculate average annual runoff in the Beichuan River basin, 30 m DEM data were used to extract the hydrogeomorphic characteristic factors related to runoff． The topography of the Beichuan River basin was found to tend to be flat from the upstream to the downstream, and the catchment capacity was stronger with the increase of river network development． Correlation was analyzed between average annual runoff and hydrogeomorphic characteristic factors． Hydrogeomorphic characteristic factors were selected through collinearity diagnosis, to establish linear regression equation． Of macro topographic factors, two factors showed high contribution rates: terrain humidity index (50.66%), surface roughness (44.33%)． For micro topographic factors, contribution rates were: profile curvature 36.25%, elevation 27.26% and slope aspect variation 24.31%． The river network form index contribution rates were: node connection rate 54.16%, area elevation integral 32.95%． Those results will: 1) help in-depth understanding of relationships between hydrogeomorphic characteristics and runoff, 2) help studying hydrogeomorphic characteristics upstream and downstream．