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Reducing Flooding in Coastal Communities



DNREC’s Delaware Coastal Programs (DCP) office has partnered with a group of seven unique coastal municipalities on a comprehensive assessment of impervious surface coverage. The project will produce community-specific strategies for reducing existing and future impervious surface coverage and increasing stormwater infiltration.

A Coastal Community

Local Leadership

In early 2018, the City of Rehoboth sought interest from other coastal communities to form a partnership to apply for assistance in conducting the study of impervious surface coverage to address its impacts on stormwater management, flooding, and water quality. The partnership includes the Cities of Lewes and Rehoboth, and the towns of Henlopen Acres, Dewey Beach, Bethany Beach, South Bethany, and Fenwick Island.

Each of these communities faces additional challenges associated with rising sea-levels, based on their proximity to the Atlantic Ocean and Delaware’s Inland Bays. Rapid growth, compounded by impacts to the groundwater table and growing floodplain, led these coastal communities to seek out strategies for reducing impervious surface coverage.

Input and Outreach

Stakeholder and public participation are important to this effort. Through meetings with municipal officials and public outreach events, residents and community leaders have the opportunity to add their ideas and brainstorm strategies for addressing these challenges.

The work of the partnership will be promoted through information sharing across the state and region so that other municipalities and communities may benefit.

Project Steps

Planting to control runoff

Summary of options that will increase stormwater infiltration and reduce future impervious surface coverage

AECOM will summarize current best practices regarding stormwater infiltration across the state and region. They will also meet with the coastal municipalities, appropriate stakeholders, and state agencies to identify current practices and codes that apply to impervious surface coverage. With this information they will develop a community-based guide with tools reduce stormwater runoff as well as their cost, feasibility, maintenance, and strategies for incentivizing BMPs.

Status: Completed

Evaluation of current status of impervious surface coverage in each municipality’s boundaries

The Delaware Coastal Programs office will work with the University of Delaware’s Department of Geography to determine the current (2016) and past (2007) amounts of impervious surface in the municipalities.

Status: Completed

Development of best practices for each municipality to control future impervious surface coverage and final assessment report

KCI will hold meetings with the municipal stakeholders and the public to identify preferences in community practices and to determine unique challenges to each one. After collecting this information they will develop specific best practices for each municipality and will present them at their Council meetings. This report will also contain community and resident feedback on stormwater control options.

Status: Completed

Regulatory Options

Delaware Communities have the option to enact regulations more stringent than the State’s Sediment and Stormwater Regulations and may want to consider inclusion of the final project report’s suggested practices in their permitting process.

There are three general scenarios upon which Best Management Practices (BMPs) for impervious surface coverage may be placed to manage runoff from:

  • existing developed areas on a voluntary basis
  • small impervious areas being proposed that would not otherwise fall under the third scenario
  • larger (greater than 5,000 square feet) each disturbance being proposed

Typically, there are no regulatory requirements for projects in the first category, but coastal communities may want to consider inclusion of these types of projects in their building permit processes if for no other reason than to track installations.

Similarly, projects in the second category may or may not fall under current requirements depending on the size and type of proposed activity.

Projects in the third category would trigger compliance with the State’s Sediment and Stormwater Regulations, which would necessitate a permit from the Sussex Conservation District. Lots in the coastal communities are frequently less than 5,000 square feet and are exempt from the Sediment and Stormwater Regulations regardless of the activity proposed.




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