CSDMS Summer Science Series III: River morphology and flood risk in the Pacific Northwest, US
Flood hazard in rivers can evolve from changes in the frequency and intensity of flood-flows (hydrologic effects) and in the channel capacity to carry flood-flows (morphologic effects). However, river morphology is complex and often neglected in flood planning. Here, we separate the impacts of morphology vs. hydrology on flood risk for 48 river gauges in Northwestern Washington State. We find that morphologic vs. hydrologic forcings are comparable but not regionally consistent. Prominent morphologic effects on flood-risk are forced by extreme natural events and anthropogenic disturbances. Based on morphologic changes, we identify five categories of river behavior relevant for flood-risk management.