Agriculture Practices in an Urban Landscape: Bioreactors and Saturated Buffers
Grant funds will be utilized to install a bioreactor and saturated buffer system to capture and treat runoff from an urban watershed which drains into Duck Creek. The City of Davenport and partners will be utilizing local resources to contribute to the design, construction and monitoring efforts to assess the effectiveness of these practices in an urban landscape. The goal of this demonstration project is provide the information needed to expand similar installations at the city, county and state level.
The City of Davenport and the Scott County Soil and Water Conservation District (SWCD) plan to address surface stormwater run-off from an 11-acre residential watershed that empties into Duck Creek. Using the Water Quality Volume (WQv) calculation, it estimated that the area sheds 24,960 cubic feet of water per a rain event of 1.25 inches. The indicated practices will treat this volume of water, removing sediment, nitrates, phosphates and other pollutants.
By applying and modifying common nutrient reduction agriculture practices, it is anticipated that treated urban stormwater will result in similar pollutant load reductions. The City of Davenport, working in conjunction with Ecosystem Services Exchange will design a system of two bioreactors and a saturated buffer that will treat the runoff. The City of Davenport will begin to stock pile woodchips on site during winter brush removal. This will reduce the cost of the bioreactors and allow the construction of the system to begin in a timely matter. The watershed drains to one stormwater outlet pipe. This outlet pipe will be outfitted with a sediment trap, which will prevent sediment and trash from entering the system. The water will enter a lift station and be diverted either directly to the saturated buffer, or to the bioreactors. Water that exits the bioreactors will then be directed to the saturated buffer. By separating the water we hope to monitor the effectiveness of both the saturated buffer, the bioreactor, and the system as a whole. It is anticipated that the combination of practices will clean, slow the velocity and reduce the volume of urban water runoff.