From The Blog

How an Automatic Gate Improves Water Management Responsiveness

Watch the Video of KICA’s New Outfall in Action.

In situations where flooding is a threat, quick action is essential. KICA manages the island’s drainage basins at 10 outfalls where gates allow water to flow into or away from the island. Formerly each of these outfall gates opened and closed manually, taking considerable time and physical effort. Now, the island’s second-largest drainage basin is controlled remotely and automatically, increasing the association’s ability to act efficiently.

When a tropical storm or hurricane is approaching, time is of the essence. Gates need to open at low tide so that water can drain away from the island as the tide lowers and pulls it out, which adds rain water storage capacity to the ponds, a valuable way to combat flooding. Gates need to close at high tide so that as the water level rises, water is not pushed back into the drainage system and ponds, negating the drainage efforts. Kiawah has 10 outfalls, and a team of four Lakes department staff cannot be in 10 places at once, manually turning a wheel to open or close a gate.

Manually raising and lowering the gates is even more difficult when an evacuation order has been issued and staff aren’t onsite. An automatic gate can be accessed remotely, allowing staff to control the gate from anywhere in the world, at the optimal time. This spring, the Beachwalker Drainage Basin outfall at Inlet Cove was converted to an automatic gate, making the management of that outfall as easy as a click of a button. Staff can be safely evacuated, and instead of waiting to open the gate upon their return, they can take advantage of outgoing tides to pull water away from the island immediately after a storm. The automatic outfall is also connected to a generator, so if the power goes out, the generator can keep the outfall operational. This project was much more complex than simply swapping out some equipment, and KICA is thankful to the professionals and contractors who worked with us to design and build this solution.

Plans are underway to automate a second outfall at the Canvasback Drainage Basin in 2022. This will optimize the management of the island’s two largest drainage basins. In future years, other outfalls may be considered for the conversion as well. This is part of KICA’s commitment to optimizing island drainage. Some other steps the association has taken over the years are updating miles of metal drainage pipes installed by the original developer (about $1 million is budgeted each year for drainage repair) and initiating the Flood Mitigation infrastructure projects, which are scheduled to be completed this year. Automating outfall gates was a recommendation from the Town of Kiawah Island’s Flood Mitigation and Sea Level Rise Adaptation report.

Now that the project is complete, the outfall gate management is the responsibility of Lakes supervisor Matt Hill. Instead of cranking open or closing 10 outfalls, the team will only have to manually open or close nine, and this important stop can now be skipped, because it’s a simple click-of-a-button to control Kiawah’s second-largest drainage basin.