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May

19

2022

From The Blog

2022 Flood Mitigation Special Assessment and Project Updates

Special Assessment

In the spring of 2020, Kiawah Island Community Association (KICA) members voted to approve a Flood Mitigation Special Assessment to fund six infrastructure improvement projects that will alleviate hazardous flooding on Kiawah’s main roads to keep them passable in many heavy rainfall scenarios. The special assessment is billed annually in June for five years: 2020-2024. The special assessment is $130 per improved property and $65 per unimproved property. 

The 2022 special assessment will be charged to your KICA member account on June 1. Notices will be emailed to the primary contact of your household on June 5. Payment is due by June 30, 2022.  To pay this assessment, login and visit the Billing and Payment tab of your member account. (If you purchased your property after May 1, 2020, the balance of the 5-year special assessment should have been paid in full by the previous owner at closing.)

This five-year special assessment was required to accomplish the package of infrastructure improvements because the community association does not have a funding source to build new infrastructure. Typically infrastructure is built by a developer and then conveyed to the community association to maintain. Drainage repairs and replacements are funded by KICA’s reserve budget, but there is no fund for new infrastructure, so a special assessment and vote was necessary.

To view a report of the status of finances associated with this special assessment and project costs, view the PDF below.  

Financial Overview of Flood Mitigation Assessment and Projects (PDF)

 

Flood Mitigation Map - Before Improvements

KICA’s Flood Mitigation Efforts

Water is one of Kiawah’s greatest assets – the ocean, marsh, river and ponds. The island’s natural abundance is a big reason why people are drawn to the island and why they stay, but living with water requires careful stewardship.

In 2019, KICA established the Water Management Task Force to evaluate and refine KICA’s approach to water management, and determine a comprehensive solution to address Kiawah’s commonly recurring flooding issues.

As the first step to any short or long-term flood mitigation efforts, international water resilience experts encourage communities to focus on water removal through drainage optimization. The task force determined that six strategic infrastructure improvement projects would optimize Kiawah’s drainage system, allowing water to more efficiently exit the system. This would reduce hazardous flooding in significant portions of the island during many heavy rainfall events and position Kiawah to recover more quickly from storm surge.

Before the infrastructure improvements, a severe rainfall at high tide could flood Kiawah’s main roads, limiting access to and from the island. Statistically, this happens annually and it is a public safety issue. In the same rainfall scenario, with improvements to Kiawah’s infrastructure, main roads are better able to remain open to traffic and hazardous flooding on common property throughout many neighborhoods will be resolved.

The new infrastructure was developed by Stantec, an international engineering firm that has a successful history working with the association. The projects were selected because they each solve an existing detrimental flooding issue, and they work in tandem to relieve the drainage system and maximize efficiency.

In two independent digital hydrologic models of Kiawah Island, simulations confirm that the proposed new infrastructure successfully eliminates hazardous flood waters, in the scenario of the highest average annual rainfall at an average high tide, with no unintended water displacement or erosion issues. Now that several of the projects are complete, two tropical storms have also confirmed their effectiveness.

These strategic improvements communicate that Kiawah is a proactive barrier island community that safeguards property values by implementing strong flood mitigation practices. In the short and long-term, property values on Kiawah will be strengthened with this new infrastructure.

Projects and Status Updates

Project 1

Status – Complete

Project One is in the area of the Kiawah Island Parkway and Sea Marsh Drive near the west end of the island. Before improvements, Sea Marsh Drive flooded in this location. Water from the road is designed to shed into Pond 21, but the water level in this pond stayed too high due to insufficient capacity to drain, so there was no place for water to be displaced. The solution was to add another pipe from Pond 21 to its neighboring pond, to increase its capacity to flow through the pond system and out through the drainage system. This improvement significantly reduces rainfall flooding on Sea Marsh Drive.

Project 2

Status: Complete

Project Two is in the area of the Kiawah Island Parkway and Sea Forest Drive near Fire Station #4. Before improvements, the Kiawah Island Parkway flooded in this location with 12 inches of water (the height of some car tailpipes) at least once annually, which could prevent access to most of the island. There is no possible detour in this area, so it is critical to maintain access here. Overall drainage capacity issues also contributed to significant flooding (up to 26 inches) on Sea Forest Drive and many side streets.

The solution included adding a new water outfall to the marsh at an existing inlet and raising an existing berm at that inlet to prevent tidal water from coming in and flooding the parkway. Previously, one outfall at Inlet Cove drained all of the ponds on the west end of the island up to the V-gate – 37 ponds and over three miles of drainage. The new outfall now drains The Settlement neighborhood on the north side of the parkway, relieving the Inlet Cove outfall from draining this one-mile section. The additional outfall helps keep the Kiawah Island Parkway clear, and alleviates hazardous flooding in The Settlement neighborhood and throughout West and East Beach areas. This project had the greatest impact of all of the flood mitigation projects and so it was accomplished first.

Project 3

Status: Complete

Project Three is in the area of the Kiawah Island Parkway and Green Dolphin Way. At this location, the Kiawah Island Parkway’s elevation dipped, creating a bowl that held flood water. There is also no possible detour around this part of the road, so it is critical that the road remains open to traffic. The solution involved raising 450 feet of the parkway to eliminate the bowl.

Project 4

Status: Planned for Fall 2022

Project Four is in the area of the Vanderhorst Gate (V-gate). This area is low and can hold water from rainfall. In some cases, a nearby pond can push excess water onto the road through curb drainage, compounding flooding. There is no possible detour in this area, so it is a priority to maintain traffic flow in this location. The solution is to add a flap gate to the pipe from the nearby pond, so that water cannot be pushed up into the intersection, and install a pump so that water can be pumped out from the V-gate area, keeping it passable for cars. The pump can also alleviate Governors Drive flooding in the Project Five area.

Project 5

Status: Planned for Fall 2022

Project Five is in the area of Governors Drive and Halona Lane (across from the Turtle Point maintenance facility). A tidal inlet at the end of Halona Lane can cause flooding on Governors Drive, in an area where there is no possible detour. A weir, a low barrier to reduce the infiltration of minor tides, and a flap gate on the end of the pipe will reduce flooding in Indigo Park and on Governors Drive. A new dry detention area next to Governors Drive will collect excess rainwater. If needed, the pump at the V-gate could also be connected to this area to relieve road flooding.

Project 6

Status: Inlet Dredging Complete, Pipe Reconfiguration Planned for Fall 2022

Project Six is in the area of Governors Drive, between the Vanderhorst Mansion (across from Flyway Drive) and Persimmon Court. Blocked pipes and an inefficient drainage configuration cause flooding on Governors Drive. The first step was dredging the existing inlet to remove several decades of sediment for an efficient path for water to exit into the Kiawah River.  The rest of the solution will include adding pipes, reconfiguring pipes, adding flap gates to pipes to prevent tidal water from entering the drainage system, and raising the level of pipes so that water efficiently drains from the road and area ponds into the inlet. A weir will also be added to the end of Pond 56, to prevent tidal water from infiltrating and overflowing the pond.