Evaluating the performance of a retrofitted stormwater wet pond for treatment of urban runoff
| Autor: | David J. Sample, Daniel Schwartz, Thomas J. Grizzard |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Watershed
Nitrogen 0208 environmental biotechnology Stormwater 02 engineering and technology 010501 environmental sciences Management Monitoring Policy and Law 01 natural sciences Waste Disposal Fluid Rivers Retention basin Water Quality Cities Ponds 0105 earth and related environmental sciences General Environmental Science Urban runoff Hydrology Environmental engineering Virginia Phosphorus General Medicine Pollution 020801 environmental engineering Total maximum daily load Environmental science Water quality Eutrophication Surface runoff Environmental Monitoring |
| Zdroj: | Environmental monitoring and assessment. 189(6) |
| ISSN: | 1573-2959 |
| Popis: | This paper describes the performance of a retrofitted stormwater retention pond (Ashby Pond) in Northern Virginia, USA. Retrofitting is a common practice which involves modifying existing structures and/or urban landscapes to improve water quality treatment, often compromising standards to meet budgetary and site constraints. Ashby Pond is located in a highly developed headwater watershed of the Potomac River and the Chesapeake Bay. A total maximum daily load (TMDL) was imposed on the Bay watershed by the US Environmental Protection Agency in 2010 due to excessive sediment and nutrient loadings leading to eutrophication of the estuary. As a result of the TMDL, reducing nutrient and sediment discharged loads has become the key objective of many stormwater programs in the Bay watershed. The Ashby Pond retrofit project included dredging of accumulated sediment to increase storage, construction of an outlet structure to control flows, and repairs to the dam. Due to space limitations, pond volume was less than ideal. Despite this shortcoming, Ashby Pond provided statistically significant reductions of phosphorus, nitrogen, and suspended sediments. Compared to the treatment credited to retention ponds built to current state standards, the retrofitted pond provided less phosphorus but more nitrogen reduction. Retrofitting the existing stock of ponds in a watershed to at least partially meet current design standards could be a straightforward way for communities to attain downstream water quality goals, as these improvements represent reductions in baseline loads, whereas new ponds in new urban developments simply limit future load increases or maintain the status quo. |
| Databáze: | OpenAIRE |
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