High-resolution flood precipitation and streamflow relationships in two US river basins

Previous studies have examined these relationships, but they lacked the high-resolution precipitation data necessary to analyse rainfall-streamflow correlations for individual flood episodes. The present study addresses this limitation by examining rainfall-streamflow relationships in two topographically and climatically different river basins: the Wabash River basin in Indiana and the Willamette River basin in Oregon, using high-resolution, sub-basin precipitation and discharge data.

Results show that flood rainfall-streamflow relationships are highly spatially variable on a sub-basin scale. In the Wabash basin, strong positive correlations exist between rainfall and streamflow near urban areas and slight terrain gradients during flash floods, while weaker correlations between rainfall and streamflow are observed in other areas of the basin and for slow-rise floods. In the Willamette basin, strong positive slow-rise flood rainfall-streamflow relationships occur in referenced gauges in the eastern, mountainous part of the basin, while strong negative correlations occur in non-referenced gauges near reservoirs along the main rivers.