Dams: What You Need to Know & How to Maintain Them
Dams are large barriers that control the flow of fresh water in order to improve water quality; provide drinking water supply resources; support irrigation and industrial needs; and most importantly help provide relief from flooding during large rain events. For instance, the City proactively lowers water levels at City-maintained dams and ponds in Raleigh prior to a large rain event to provide additional lake storage. This reduces impacts to properties downstream of the dam and ensures the ongoing safety of Raleigh residents.
Dam Removals or Repairs
Dams vary in size (i.e. small scale ponds versus larger dams located on rivers), and can be considered high-hazard depending on their function, age, and condition.
The North Carolina Department of Environmental Quality’s North Carolina Dam Safety evaluates annual inspections for dams in their jurisdiction (including City and privately owned dams) to assess the condition of the dam structure. After an evaluation, North Carolina Dam Safety will notify dam owners if it is determined that a dam is in poor condition. Then, the owner of the dam is responsible for repairing the dam or completely removing the dam structure from their property.
When a dam is repaired or rehabilitated, like at Northshore Lake, Carolina Pines Lake, and Lower Longview Lake in Raleigh, the new dam is designed and constructed to meet current North Carolina Dam Safety requirements and to offer more sustainable stormwater infrastructure throughout the city that reduces flooding and/or improves water quality.
Meanwhile, removing a dam completely restores the land back to its natural state. This reestablishes natural water flows, provides a healthier habitat for fish and wildlife, improves water quality, and eliminates safety concerns of a failing dam.
After a dam is constructed, regular maintenance is completed on City-owned dam structures to make sure that dam infrastructure is functioning properly and remains in good condition. Private property owners are responsible for maintaining dams on their property. Here are a few tips to help with dam maintenance:
- Repair any issues with the dam structure (i.e. remove woody vegetation and trees, and check for cracks/leaks along the dam structure). Property owners should contact North Carolina Dam Safety at 919-707-9200 if there are concerns with a dam on their property and to coordinate any dam repairs or removals. Contact Raleigh Stormwater at 919-996-4174 with questions related to City-maintained dams;
- Keep grass and brush on top of and along the dam short. Regularly mow and clear these areas;
- Place vegetation, like plants and shrubs, along the stream bank to maintain good water quality, limit erosion, and stabilize the stream bank both upstream and downstream of a dam and lake; and,
- Pick up any litter or debris surrounding the lake and at the dam structure to reduce downstream pollution along rivers and streams.
To learn more about dam construction and maintenance, call 919-996-4174 or email Albert.Cole@raleighnc.gov.
This article was originally printed in the Stormwater Management Division's Urban Watersheds publication. Subscribe to learn more and to receive stormwater-related news.