From The Blog

Electronic Outfalls Speed Up Response Time at Kiawah’s Two Largest Drainage Basins

In a severe rainfall event, quick action is essential to move water off the island through the island’s drainage systems. KICA manages 10 outfalls where gates allow water to flow into or away from the island. Now, with the completion of an electronic outfall gate at the Canvasback Outfall, the island’s two largest drainage basin outfalls can be operated remotely by KICA staff, enabling staff to be more responsive to severe weather events regardless of where they are. (See a 2022 video of the Beachwalker outfall in action here.)

Formerly, each of the island’s 10 outfall gates opened and closed manually, taking considerable time and physical effort. KICA’s team of four Lakes department staff cannot be in 10 places at once, manually turning a wheel to open or close a gate. Additionally, 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 rainwater 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. The electronic gates can be accessed remotely through an internet-connected app, allowing staff to control the Beachwalker and Canvasback systems from anywhere at the optimal time.

When a tropical storm or hurricane is approaching, time is of the essence. It’s particularly helpful during hurricane season: staff can be safely evacuated, and instead of waiting to open the gate until they are allowed to return, they can take advantage of outgoing tides to pull water away from the island immediately after a storm. The gates are connected to a generator, so if the power goes out, the generator can keep the outfall operational. (Note that the remote function depends on an internet connection. If power and internet connectivity are unavailable, the outfalls must be operated manually.)

In future years, other outfalls may be considered for the conversion as well. This work is part of KICA’s annual commitment to optimizing island drainage.