Orange County NC Website
Browse       Search
45 <br /> Creating Optimum Conditions for Pollutant <br /> Removal and Treatment <br /> Creating a marsh at the inlet enhances the growth of vegetation and the trapping of sediment and <br /> other pollutants. Aquatic benches along the sides also encourage vegetation. The plants enhance <br /> pollutant removal by drawing nutrients from sediments. Algae attaches to these plants and can <br /> draw nutrients directly from the water. A created wetland is desirable, but consideration should <br /> be given to restricting vegetation to a confined area where it can be managed so the entire pond <br /> does not become a jungle of vegetation, cold blooded wildlife, and insects. <br /> The greatest initial settling occurs in the upper end of the pond where the larger, heavier <br /> particles fall out as the flowing runoff looses velocity as it enters the still water in the pond. For <br /> this reason it is necessary to provide a baffle or other structure near the inlet to concentrate <br /> sediment accumulation where it can be reached for periodic removal as part of maintenance. <br /> Consideration for Multiple Uses <br /> Careful evaluation and planning is needed since vegetation may make the pond unattractive for <br /> use as recreation and landscaping. If the pond is to be multipurpose, marshes and benches should <br /> be isolated from other areas to be used for fishing, boating, swimming, etc. <br /> Vegetation on or close to the dam should be discouraged and prevented through routine <br /> maintenance. Roots can weaken the dam, and vegetation attracts burrowing animals that earl <br /> weaken it further. Thick vegetation makes maintenance more difficult, which may delay wort <br /> and allow growth to spread further until major clearing is required. <br /> Refer to the sources listed in the references for more information and for suggested plants to <br /> establish in a pond. <br /> Safety <br /> A fence is required around the pond to control access. Gates sized for either pedestrian or <br /> vehicular access (for maintenance) should be installed at appropriate locations. At the designated <br /> access to a public right-of-way the gate must be wide enough to accommodate equipment needed <br /> to mow and otherwise maintain the pond and to excavate accumulated sediment when the time <br /> comes. <br /> The owner should consult with an attorney concerning liability for accidents, legal requirements <br /> for fencing and access, insurance, etc. <br /> Review of Pond Design <br /> A pond can have both positive and negative impacts on the natural environment and the <br /> development and review of the design will consider these impacts. However, develop of the site <br /> will have impact downstream with or without the pond, so the pond is necessary to mitigate the <br /> impact and contain pollutants before they are washed downstream. <br /> DRAFT 10 June 1993 <br />