| dc.description.abstract | The Trailwoods residential neighborhood (Norman, OK) included two instrumented watersheds (each approximately 2.3 acres), with the purpose of quantifying the impact on stormwater quantity and quality through implementation of low impact development (LID) best management practices (BMPs). The control watershed, Trailwoods East (TE), utilized traditional urban stormwater management while the treatment watershed, Trailwoods West (TW), included rain barrels, rain gardens, diversion downspouts, and permeable pavement. The toe of each watershed was outfitted with a trapezoidal flume which allowed for measurement of continuous discharge and calculation of storm event total runoff volume and peak volumetric discharge rates. A storm event-activated autosampler was used for collection of flow weighted composite stormwater samples. Once water levels within the flume reached a predetermined depth, a 20-mL sample was collected immediately and for every 50 cubic feet per second (CFS) of stormwater that passed the measurement point. A suite of stormwater runoff constituents were analyzed, including nutrients (nitrogen and phosphorus compounds), total suspended solids and trace metals. Ecosystem services provided by the LID BMPs at the study site were also determined. Specifically, provisioning of water from rain barrels and regulation through flood attenuation and nutrient retention by the suite of LID BMPs were the focus of the valuation study. A total of 10 storm events were captured, with precipitation intensities ranging from 0.48 to 2.64 in hr-1. LID BMPs decreased the total volume of stormwater by 29,277 cubic feet (CF) or 26.5 percent. Peak volumetric discharge rates were significantly different (p = 0.40) by 1.24 CFS or 47 percent. Mean TSS concentrations were different by 33.7 mg/L or 49 percent when comparing TE control to TW treatment. Mean nitrate-nitrogen concentrations were significantly different (p = 0.01) by 0.68 mg/L or 63 percent. However, mean total phosphorus (TP) and total dissolved phosphorus (TDP) concentrations were higher for TW compared to TE watersheds by 0.17 mg/L or 47 percent and 0.02 mg/L or 29 percent, respectively. The valued ecosystem services provided by LID BMPs showed that, given time, LID BMPs can potentially outweigh the capital costs of construction and provide long-term economic benefits. | en_US |
