Retention Pond Maintenance, Go Green Hilliard Style

Many suburban neighborhoods have retention ponds to manage stormwater runoff volume and mitigate any potential pollution from this runoff. Over the course of time these ponds can fill up with sediment and other debris, thereby reducing their capacity and effectiveness. Another unwanted problem is that these increasingly shallower ponds can become inundated with algal growth during the summer months.

Few options, however, are available to restore retention ponds to their original depth and capacity. One commonly used method is to drain the pond before digging out the accumulated material. This, unfortunately, is a messy and time consuming process, and often requires restoring the landscaping around the pond. In addition, many ponds aren’t easily accessible by heavy equipment and the volume of material to be disposed of can be excessive.

Another more environmentally friendly method is to use divers and suction pumps to remove and transfer the sediment to an onsite geotextile (permeable fabric) container where it can dry. Over time the sediment will dewater, thus reducing the volume of material. Once dry, the sediment can either be hauled away; or even better, it can be used as landscaping material or simply graded out and reseeded with grass.

This onsite sediment removal/dewatering method was employed by the City of Hilliard this past month at the Carrington pond adjacent to Britton Parkway. Sediment was removed from the north pond and left onsite in geotextile containers to dewater, thereby reducing the amount of material to be managed and maintaining the aesthetic value of the pond while avoiding the cost of landscaping the area around the pond. Once dry, the geotextile containers are opened and the remaining sediment solids are excavated and loaded into trucks for transport to an approved disposal/recycling facility.