Wake County helps protect streams, lakes, and downstream infrastructure by reducing erosion and keeping sediment on-site during land-disturbing activities.
Why is sediment the most common pollutant in rivers and lakes?
Sediment is the most common pollutant by volume in surface waters for several reasons:
- Sediment is everywhere. It comes from the land beneath our feet when topsoil detaches from the land surface and becomes loose. Under the right conditions, any exposed land surface can become a pollutant source. Any ground not covered by vegetation or hardscape is at risk. Ground cover protects sediment from being moved by rain, wind, and even foot traffic.
- Construction is frequent. Land-disturbing activity regularly exposes bare soil, which increases the chance that sediment will be carried off-site by stormwater runoff.
- Sediment does not break down easily. Other pollutants, such as sewage or excess nutrients, can sometimes be biologically or chemically removed from the environment. Sediment cannot, because it is weathered rock. It usually must be physically removed, which can require significant labor and material costs.
- Erosion can trigger more erosion downhill. Bare ground uphill is less stable during storms and cannot slow or infiltrate water effectively. Faster runoff can destabilize slopes, detach more topsoil, and in some cases cause mass wasting or streambank collapse.
Why is sediment considered a pollutant?
While sediment may seem natural, excessive amounts in water bodies and accumulated in infrastructure can have serious environmental and economic impacts.
- Very fine soil particles can remain suspended in the water column for months, making water look brown and muddy. Muddy water reduces sunlight for aquatic plants, makes it harder for fish to find food, can smother fish eggs and benthic organisms, disrupt fish gill function, and degrade aquatic habitats.
- Sediment can carry other pollutants, including fertilizers, metals, and pathogens, which attach to sediment particles and worsen water quality.
- Accumulated sediment in stormwater infrastructure and drinking water reservoirs reduces capacity and increases maintenance and treatment costs. Excess buildup can also put infrastructure out of compliance with federal and state regulations, and removal often requires costly mechanical dredging or excavation.
Key regulations
NC Department of Environmental Quality (DEQ) state regulations
Wake County is delegated by the State of North Carolina to operate a local erosion control program. The overall goal of the Sedimentation Pollution Control Act (SPCA) and the NC Administrative Code Title 15 Chapter 4 is to prevent visible sedimentation into lakes, streams, natural watercourses, and adjoining properties. The SPCA outlines regulatory requirements and grants authority to the Sedimentation Control Commission (SCC) and the Land Quality Section (LQS). The Code provides the administrative framework for how the SCC and LQS enforce the SPCA.
To report sediment problems to the State, contact the appropriate DEQ - DEMLR Regional Office that serves your area or use the Division of Energy, Mineral, and Land Resources toll-free hotline: 1-866-STOPMUD.
Wake County Unified Development Ordinance Article 10 – Erosion and Sediment Control
Wake County's erosion control regulations may be found in Article 10 of the Wake County Unified Development Ordinance. These regulations establish sediment and erosion control requirements for new development.
Wake County administers erosion control regulations for all unincorporated areas, as well as six municipalities through interlocal agreements: Garner, Knightdale, Morrisville, Wendell, Rolesville, and Zebulon.
Federal rules
How Wake County supports responsible land development activities
- Review construction plans for each land development over one acre.
- Inspect construction sites for compliance with regulations and the approved design plan.
- Issue enforcement actions when land development is out of compliance.
- Investigate complaints from Wake County residents to identify and address violations.
- Provide education and guidance to development partners and residents.
What can homeowners do to reduce erosion and sedimentation?
- Cover bare soil with permanent ground cover. Grass and other plants are the best options because roots stabilize soil and leaves reduce the impact of raindrops. Plants are especially important on slopes and near waterways.
- If bare soil cannot be planted right away, use temporary cover such as mulch, stones, tarps, or plastic sheathing until the growing season returns and plants can become established.
- Direct downspouts into vegetated areas or rain gardens instead of onto bare ground or driveways. This helps water soak into the ground rather than washing soil away.
- Minimize disturbed areas during landscaping or construction. If digging or grading is necessary, cover exposed soil as soon as possible and use practices such as silt fences and stabilized construction entrances to trap sediment on-site.
- Avoid compacting soil. Compacted soil is more prone to erosion and less able to absorb water. Stay off wet soil with heavy equipment or repeated foot traffic when possible.
- Create buffer zones near creeks or drainage ditches. Native vegetation in these areas can help filter stormwater runoff before it reaches waterways.
What can builders and contractors do to control sediment?
- Limit exposed areas by phasing grading so that only the necessary portions of the site are disturbed at one time.
- Follow the approved plan to install and maintain erosion and sediment control measures.
- Maintain all erosion and sediment control measures after storms or heavy site activity.
- Avoid compacting soil wherever possible.
- Stabilize inactive areas within 7 or 14 calendar days, as required by the approved plan.
- Protect stockpiles and keep them away from the site perimeter.
- Control site access and tracking. Use stabilized construction entrances, such as rock pads, and street sweeping to prevent sediment from leaving the site.
- Conduct regular inspections weekly and after significant storm events, and correct problems immediately to avoid violations.
- Train the entire team so everyone on-site understands sediment control basics and their responsibilities under the Stormwater Pollution Prevention Plan (SWPPP).