Geomorphic response to urban development with infiltration-focused stormwater management in headwater streams
Abstract
Urban development and the associated replacement of vegetated land cover with impervious cover has led to altered flow regimes, degrading physical stream habitat through accelerated vertical and lateral channel erosion. To mitigate urban impacts on streams, new development approaches have attempted to improve stormwater management by dispersing runoff and promoting infiltration throughout the entire watershed. Clarksburg, Maryland is a rapidly developing suburb of Washington, D.C. where a significant investment in infiltration-focused stormwater management facilities have been incorporated to manage runoff from impervious surfaces. This study focuses on three headwater watersheds within Clarksburg that have transitioned from primarily agricultural to urban land use, and two additional nearby urban and forested watersheds that underwent little change over a 14-year period. We investigated physical channel changes from 2004 to 2018 using both multitemporal airborne light detection and ranging (lidar) and annual field-based measurements at discrete cross-sections. In-stream habitat surveys were also conducted annually to assess changes in riparian habitat quality over time. Geomorphic changes from lidar and cross-section data indicated areas of both channel erosion and stability at cross-section monitoring locations. Watershed-scale analyses of change from lidar also detected other areas of increased deposition during the construction phase of development and incision near stormwater management outlets. Examining geomorphic and habitat changes simultaneously allows us to further investigate linkages between the two and develop methods to assess and monitor habitat conditions using lidar. This method could be used to evaluate the success of infiltration-focused stormwater management in mitigating headwater habitat impacts caused by the urban stream syndrome.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFMEP22B..08M
- Keywords:
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- 1632 Land cover change;
- GLOBAL CHANGE;
- 1813 Eco-hydrology;
- HYDROLOGY;
- 1825 Geomorphology: fluvial;
- HYDROLOGY;
- 1862 Sediment transport;
- HYDROLOGY