Introduction to Wet Ponds

Wet ponds are one of the most common stormwater control measures in new and existing developments in southeastern North Carolina. A wet pond is a stormwater facility constructed through filling and/or excavation that provides both permanent and temporary storage of stormwater runoff. It has an outlet structure that creates a permanent pool and detains and attenuates runoff inflows and promotes the settlement of pollutants. The primary treatment mechanism within a wet detention pond is sedimentation or the settling of particulates. Some municipalities have an additional requirement for the capture of a certain quantity of water.

What Ponds Do

Proper maintenance of stormwater ponds is critical to reduce adverse impacts on downstream waterways. Poorly performing or maintained pond systems can act as sources of pollution (Lewitus et al., 2003). Common issues in ponds include: How can a pond buffer help with these issues? A robust pond buffer can help to extend the life of a pond by filtering out sediments, the deep roots of vegetation can prevent erosion by holding pond banks in place, and pond buffer plants can help to take up excess nutrients that exacerbate nuisance aquatic weed growth.

• Remove pollutants, including sediment
• Improve health of streams, rivers, and intracoastal
• Help make our waters swimmable and fishable
• Sediment Accumulation
• Bank Erosion
• Overgrowth of Aquatic Weeds

Getting Pond Plants Established

• When adding new plants to a pond buffer, care should be taken to choose plants that will be appropriate for the water level. You must remember that water levels may fluctuate in a pond depending on rainfall or ground water levels. Plants may need to be watered when getting established if pond levels are low.
• Plants can come in pots, plugs, or as bulbs. Metal landscaping staples may be needed to hold plants in place, especially in muddy banks until the plants are established.
• Turtles can be a nuisance and eat newly planted vegetation. It may be necessary to create a small fence using chicken wire to allow plants to become established. Once established, the plants will be able to withstand herbivory.

How Can I Help Maintain a Healthy Pond? 

Check for sources of additional nutrients– Aquatic plants respond to high levels of excess nutrients by growing just as any other plant would. It is important to assess sources of nutrient rich runoff.

• If turf is being fertilized nearby, be sure to take soil samples periodically to ensure that you are not overfertilizing. Never apply fertilizer to garden beds or turf before it rains; fertilizer can runoff into ponds.
• Avoid letting leaves or grass clipping enter the pond. Nutrients will be released from decaying plant material.
• Pet waste should be picked up promptly and disposed of in the trash.
• Discourage geese from swimming in the pond by having a robust vegetated pond buffer. Geese prefer a clear line of sight and will avoid ponds with a thick vegetated buffer.

Hire a reputable pond management company

If your community needs assistance to maintain a stormwater pond, hire a company that specializes in ponds.

• Aquatic weed ID is crucial. Chemical management of ponds deeply depends on the type of aquatic weeds present and the usage of the water. A good company will be able to identify specific weeds to create an effective management plan.
• Pesticide applicators that are applying chemical herbicides to water for compensation must have a current NCDA Pesticide License with an Aquatic specialty certification.

Add a vegetated pond buffer

Mowing down to the water line is bad practice for stormwater ponds. Turf has shallow roots and can allow erosion of pond banks.

• The minimum height for a buffer should be between 18-24”. Buffers can be taller than this especially with the addition of shrubby species.
• A simple 3-foot, no mow zone can be established around the perimeter of the pond to create a buffer, or specific plants can be planted to achieve a more natural pond look.
• The fall is the best time to plant and establish a new buffer zone around your pond. The cooler temperatures will allow time for pond plants to establish.

Pond Buffer Plants

Pond buffer maintenance

• Cut to 18” in the wintertime to tidy the area and allow for new spring growth
• Do not allow grass or debris to blow into the pond
• Don’t plant invasive species and remove them promptly if they pop up
• Remove tree seedlings as they come up

For more information: NCSU Pond Management Guide