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ECOLOGICAL SUSTAINABILITY IN RAPIDLY URBANIZING WATERSHEDS: EVALUATING STRATEGIES DESIGNED TO MITIGATE IMPACTS ON STREAM ECOSYSTEMS
Description:
Urbanization has profound impacts on the hydrology and ecology of streams via alteration in water temperatures, peak and base flows, and nutrient, sediment, and contaminant inputs. Storm water management (SWM) is commonly used to reduce these impacts; however, comprehensive watershed-scale studies to determine the effectiveness of SEM designs in reducing ecological impacts are scarce. With the continuing trend of urbanization, there is an urgent need to more fully understand which SWM designs are most effective and why, so that policymakers are better equipped to address the sustainability of water resources.
In 2000, the state of Maryland adopted new SWM criteria to address the impacts of urbanization on stream ecosystems. Montgomery County (Maryland) Department of Environmental Protection initiated a project in 2002 to evaluate the effectiveness of new SWM practices. Here, we propose a new partnership to significantly expand the scientific scope of that project in order to determine the SWM-related environmental responses off channel (groundwater), in-channel (surface water & streambed) and below channel (hyporheic). We will investigate the effectiveness and underlying biophysical mechanisms of these new SWM strategies. Critical questions will be answered using an empirical research design that focuses on multiple stream reaches within:
- watersheds developed with the most advanced SWM technologies;
- watersheds with older SWM designs;
- and largely forested (control) watersheds.
We will evaluate the structural and functional responses of stream ecosystems to these differing SWM designs. Using replicate sampling, we will quantify and statistically compare watersheds with respect to: discharge, rainfall-to-runoff ratios, groundwater-surface water exchange, bed particle size and mobility, suspended sediment loads, groundwater and surface water quality, macroinvertebrate composition, and the ability of streams to process nutrients and excess carbon (nutrient uptake rates, whole stream metabolism, decomposition rates).