August 2012 // Volume 50 // Number 4 // Tools of the Trade // 4TOT6
Nonpoint Source Pollution Reduction in Coastal Communities: An Extension Service Guide to Stormwater Management Practices
Managing nonpoint source (NPS) pollution is a crucial aspect of maintaining coastal water quality and ensuring viable estuarine habitats. This article provides a primer on promoting sustainable stormwater management techniques in local government, in the interest of reducing the impact of nonpoint source pollution in coastal areas.
Acting through the EPA National Pollutant Discharge Elimination System (NPDES) program, states assume a significant role in ensuring coastal water quality. Within Extension literature, there has been a strong focus on mitigating the impact of agricultural runoff through educational approaches and best management practices (Ross, Dillaha, Mostaghimi, & Heatwole, 1991; Benham, Braccia, Mostaghimi, Lowery, & McClellan, 2007). Yet, Extension agents have a role to play in educating and assisting local government in strategies to mitigate the effects of NPS from urban development as well.
Incorporating stormwater best management practices (BMPs) in local land use plans is one of many tools that Extension officials can use to help accomplish coastal water quality goals. BMPs can work in concert with low impact development (LID) procedures to provide "cost-effective, lot-level strategies that replicate pre-development hydrology and reduce the impacts of development." (Zhen, Shoemaker, Riverson, Khalid, & Mow-Soung, 2006). This primer outlines the benefits of NPS that can be undertaken by local governments, particularly those in coastal communities, to reduce pollution discharge.
NPS Pollution Strategies for Local Governments
Enact Erosion Control Ordinances
The NPDES program specifies the need for regulatory review by state agencies for construction projects that disturb at least one acre, but there are many smaller projects that do not trigger regulatory review. The cumulative impact of smaller projects often results in increased sedimentation and degradation of coastal waters. Several states delegate primary review authority to local jurisdictions that enact erosion and sedimentation ordinances that comply with state requirements.
Strengthen Onsite Stormwater Retention Standards
Many states specify a need for retention facilities (retention ponds, swales, etc.) that are designed to handle water from a storm of limited duration and intensity. By promoting stronger onsite retention standards, local governments can reduce the frequency and flooding events, while reducing severity of NPS effluent flows into coastal habitats. This also reduces the need for expensive engineered solutions to fix flooding problems.
Assess and Evaluate Minimum Parking Requirements
Local governments may see benefits in assessing required parking standards, particularly for commercial or industrial uses. Ordinances that remain tied to parking ratios, building square footages, or peak use demand calculations may unnecessarily add impervious coverage. These surfaces collect and concentrate pollutants such as oil and grease during dry periods, which are released in heavy concentrations to sensitive estuarine areas during periods of sustained or heavy rainfall (Jolley, 2003). Adjusting parking standards towards the nature of the use decreases development costs, reduces the need for variance appeals, and promotes better water quality.
Incorporate Ordinances That Require the Use of Pervious Paving Solutions
Numerous coastal municipalities have enacted requirements for the use of permeable paving solutions, particularly in commercial parking areas. Pervious concrete, grid blocks, and other alternative pavement solutions promote stormwater infiltration. They help mitigate the need for installing curb and gutter, thus reducing development and maintenance costs.
Pass or Strengthen Vegetation Preservation and Lot Coverage Ordinances
Ordinances that limit the installation of impervious surfaces aid onsite stormwater retention, reducing the release of NPS pollution. Vegetation preservation ordinances also help enhance the aesthetic properties of a community and can be used to provide buffering between less compatible land uses.
Expand the Use of Buffer Zones, Conservation Subdivisions, and Environmental Overlay Districts
Buffer zones are an integral part of many state coastal management programs. Local governments may seek to expand these setbacks to provide greater protection to ecologically sensitive waters. These areas assist in filtering stormwater while reducing the volume of effluent into estuarine environments.
The conservation subdivision is also a relatively new tool in local land use ordinances. By using incentives such as density credits, local governments can discourage the fragmentation of ecologically sensitive coastal habitats while promoting onsite stormwater retention.
Environmental overlay districts are an option for protecting significant coastal resources. These zones have been used to prevent or remedy water quality issues in a number of coastal freshwater ponds and wetlands.
Promote Voluntary Environmental Design Principles
Asking those who are proposing projects to incorporate elements of sustainable design is a simple, though perhaps underutilized avenue of achieving environmental goals. In preliminary meetings with local government agencies, staff may also suggest improvements to designs that can maintain existing site features and minimize site disturbance. At this stage, revisions require little effort or cost to modify and help accomplish water quality objectives without introducing burdensome regulatory delays.
Encourage Participation Through Education and Incentive Programs
Encouraging the installation of BMPs by citizens is a low-cost strategy to help achieve stormwater and NPS pollution reduction goals. Placing brochures in local offices and permit applications is one strategy to disseminate information. Numerous municipalities also incentivize the installation of rain barrels by providing them at reduced cost. Local outreach programs have proved effective in lessening nutrient loads to coastal waters with the use of initiatives meant to reduce the use of residential lawn fertilizers.
This article summarizes a set of strategies Extension agents can recommend and utilize to assist local governments in managing NPS in coastal communities. Many of these strategies are also applicable to non-coastal communities seeking to reduce NPS pollution.
Benham, B. L., Braccia, A., Mostaghimi, S., Lowery, J. B., & McClellan, P. W. (2007). Comparison of best management practice adoption between Virginia's Chesapeake Bay Basin and Southern Rivers watersheds. Journal of Extension [On-line], 45(2) Article 2RIB3. Available at: https://www.joe.org/joe/2007april/rb3.php
Ross, B. B., Dillaha, T. A., Mostaghimi, S., & Heatwole, C. D. (1991). Using rainfall simulators for water quality education. Journal of Extension [On-line], 29(1) Article 1IAW3. Available at: https://www.joe.org/joe/1991spring/iw3.php
Jolley, J. (2003). Nonpoint source pollution prevention and control through land use planning and management: An introduction & resource guide for protecting coastal North Carolina waters. North Carolina Department of Environment and Natural Resources.
Zhen, J., Shoemaker, L., Riverson, J., Khalid, A., & Mow-Soung, C. (2006). BMP analysis system for watershed-based stormwater management. Journal of Environmental Science & Health, Part A: Toxic/Hazardous Substances & Environmental Engineering, 41(7), 1391-1403.