Learning to Live at Sea Level

Updated: Oct 24, 2019

Over the past 15+ years, the City of Charleston and Charleston County have invested in the development of multiple community-led and community-supported plans to inform growth and preservation on Johns Island. These plans established the urban growth boundary (UGB) and provided guidance on how to:

  • Locate development to minimize storm surge and flooding risks to residents of the island

  • Prevent and/or mitigate flooding on site rather than discharging floodwaters to your neighbor

  • Encourage multi-use streets, especially along and adjacent to Maybank Highway, which support pedestrians, bicycles, and automobiles to reduce traffic on island

  • Enhance and protect open space for public use

  • Protect rural spaces, areas of historic significance, and Gullah Geechie culture on the island

These plans essentially outlined a comprehensive approach to sustainable development and conservation on the island; however, few tools have been developed to support the implementation of these plans. As a result, re-zonings, permitting, and development on Johns Island has largely been implemented on a parcel-by-parcel basis.

New Efforts Underway Need Your Support

Anyone who has been in the Lowcountry for more than a few years will notice that sea levels are noticeably higher and storm events are more frequent and stronger. It is becoming increasingly important to understand the consequences of new development on surrounding residents PRIOR to zoning, approving, and constructing developments. As development has continued on a parcel-by-parcel basis, we are seeing the consequences of these development trends in the form of increased flooding, gridlock traffic, and associated public safety hazards throughout Johns Island. We are now at a point where previous zonings and development strategies (i.e., building codes, stormwater management) should be re-evaluated and altered based on our understandings of flood hazards and best practices to protect the residents, natural spaces, and unique history and culture of the island.

Several efforts are culminating over the coming months to address planning and conservation needs on Johns Island. These include, but are not limited to:

  • Dutch Dialogues ™ – completed

  • Updates to the Stormwater Design Standards Manual – delivery to City Council anticipated in November 2019

  • Johns Island Community Conservation Initiative (a partnership project with the Center for Heirs Property, Lowcountry Land Trust, and NC State) – December 2019

  • Johns Island Drainage Master Plan – utilized for City of Charleston permit reviews, but not yet finalized for public distribution

Although these efforts provide guidance, regulations, and tools for the island, it is important that these documents don’t just sit on a shelf like others from our past. We need to champion these positive changes!

The good news is that we have the information to make the changes necessary to better protect existing and future residents of the island. Next, we need coordination across City and County Councils and the political will to permanently alter the way we zone and permit development on Johns Island moving forward.

Dutch Dialogues™: Tell Me More

The new plans outlined by the Dutch Dialogues™, updates to the Stormwater Design Standards Manual, Johns Island Community Conservation Initiative, and Johns Island Master Drainage Plan highlight opportunities for change and begin to sketch out next steps.

In particular, the Dutch Dialogues™ provide a simple, yet effective, tool that could be implemented today and deliver immediate benefits. The findings from the Dutch Dialogues™ highlight where elevation can dictate the level of development and the types of development on Johns Island: lower elevations (<6 foot) would be protected from development and higher elevations (> 15 foot) could support higher densities developments (see table below).

The plan also recommends changes to building codes (i.e., slab on grade or elevated foundation) and placement of fill according to elevations—by restricting fill and requiring elevated foundations, floodplain function would be protected in the lower elevations (<10 foot) while higher elevations could support a mixture of building types.

Finally, the plan also provides recommendations on stormwater management and treatment: the higher elevations, which typically consist of old sandy dune ridges, should manage stormwater on-site to prevent nuisance flooding downstream while lower elevations should prioritize protection of natural habitat and tree canopy.


What is "stormwater management and treatment onsite"?

The lowcountry is naturally adapted to adsorbing floodwaters so it is important to retain those natural properties during development to the greatest extent as possible. This includes:

  1. Retain native soils on site. These soils are natural sponges for rainfall, but are oftentimes scraped away and replaced with less adsorbent soils during the development process, increasing runoff during storms.

  2. Protect and enhance the surrounding tree canopy. Over 80% of rainfall is naturally absorbed and removed via evapotranspiration from native plants and trees. However, development typically strips the landscape of this vegetation increasing runoff during storms.

  3. Where possible, encourage infiltration and retention of rainfall into the soils to reduce downstream flows of stormwater. Our native landscape consists of small depressions that naturally retain stormwater, but through the development process this ‘microtopography’ is often removed and replaced with fill material. Minimizing fill can reduce the loss of this natural ‘sponge’ in our landscape, however if fill is necessary, the loss of microtopography should be accounted for and replaced with stormwater practices that mimic this process onsite (i.e., rain gardens, rain barrels, pervious material).


These recommendations build on existing plans (i.e., Johns Island Community Plan) and further highlight the importance of ongoing efforts to identify areas that are vulnerable to flooding and update Stormwater regulations to provide a larger suite of tools for addressing stormwater and flooding on Johns Island (i.e., Updates to the Stormwater Design Manual, Johns Island Master Drainage Plan).

All of these efforts cumulatively reiterate the need to provide a watershed masterplan for developed portions of Johns Island to ensure adequate storage and drainage of floodwaters now and into the future.

So What’s Next?

If we want these recommendations to move forward in a comprehensive and meaningful way for Johns Island, we need to re-evaluate zoning, restrict development to those locations that are best suited for the land, and protect rural ecosystems and historic culture on the island. To do this we need to provide an economically viable option for the existing landowners to harness the benefits of their investment—if not by development, then by its protection.

The Dutch Dialogues™ proposes market-based policies to incentivize development in the right places and in the right ways (i.e., stormwater credits, smart growth, transfer of development rights, conservation easements, green infrastructure incentives, etc.). This is not a new concept and has been recommended in previous plans (i.e., Johns Island Community Plan of 2007). However, it has become increasingly apparent that Johns Island, and the broader region, need economic incentives for protecting low-lying land from high density development and increasing development where the land can support growth (i.e., transfer of development right).

The Johns Island Community Conservation Initiative is evaluating the political willpower to undertake this type of approach for Johns Island and what it would mean for rural land outside the urban growth boundary. In addition, updates to the regulatory standards in the Stormwater Design Standards Manual will also provide incentives for stormwater treatment on-site to begin to prevent impacts of stormwater flooding downstream.

If we, as citizens of Johns Island, would like to shape the future of development on our island and the preservation of its valuable ecosystems and rich history, we need tools that provide economically viable options for land owners other than development. Most importantly, we need elected officials on both City and County Councils who will reach across their jurisdictions to work hand-in-hand to develop, legislate, and adopt these tools for Johns Island and the broader region.


Learn more about these plans, speak with City and County officials, and VOTE with Johns Island in mind on November 5th.

So, go out and vote!

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