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| Downtown Riverhead Stormwater Management | |||||
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Task 1: Subwatershed Delineation
Through the analysis of topographic maps coupled with field inspections during rain events, it was determined that the downtown Riverhead area can be broken into 2 subwatersheds (see below). This delineation, when combined with additional information such as land use and soil type, allowed us to calculate stormwater loadings. For the western subwatershed, a 2 year rain event (3 inches in 24 hours) will produce almost 4.4 million gallons of stormwater runoff!!” Task 2: Stormwater Structure Inventory
Catch basins, including both leaching basins and basins associated with conveyance systems, were located by physically searching roads and parking lots. Positions were recorded via a Global Positioning System (GPS) with sub-meter accuracy. The locations of conveyance systems were based upon existing blue prints, field observations, and input from the Riverhead Highway Department. Finally, the locations of the outfall pipes were located by walking or kayaking the shoreline and recorded via GPS. Task 3: Water Quality
In order to assess how stormwater impacts the Peconic River, water quality stations were established in order to measure coliform concentrations. These were sampled at various times during periods of dry weather as well as during rainfall events. |
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The Riverhead GIS database can be a valuable tool in stormwater management. Having a greater understanding of the subwatersheds and having a detailed inventory of stormwater structures can allow the Town to more effectively manage the issue of stormwater runoff. Also, additional information such as coliform counts in the surrounding waterbody or from outfall samples can assist in determining the location of problem areas. This information can be used in future restoration and remediation efforts. |
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