Restoring in-stream habitat in urban catchments: Modify flow or the channel?

Abstract

Urban streams have almost universally altered physical habitat conditions due to excess stormwater run-off. This includes changes to in-channel hydraulics and channel morphology. Restoration of in-channel habitat has two main levers: address the hydrology or channel morphology. Both variables impact in-stream habitat, but understanding the relative role of hydrologic and morphologic change remains a challenge. This study uses two-dimensional hydraulic modelling to examine the relative roles of flow and channel morphology in setting hydraulic conditions. We investigated four test scenarios involving the combinations of urban versus natural hydrology and urban versus natural channel morphology..