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Buoyant Weir: Protection from Flooding & Low Cost Hydropower Generation
The Buoyant Weir is a new simple technology for flood mitigation and disaster relief, and hydropower infrastructure.
It is a low-cost, environmentally friendly and easy-to-install facility that holds back water like a weir, dam or rock wall, thereby creating a water level difference between upstream and down waters. It holds back rainwater at source for a sufficient time to mitigate the maximum surge height of flood waters in a valley below. Only a few days’ notice would be needed to install such an upland reservoir. It can then be removed again for re-use.
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The Buoyant Weir is also installed as permanent solution for weirs and as an alternative to costly rock walls in tidal energy schemes.
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Video: Demonstration of the Buoyant Weir operation across high and low tides.
The Buoyant Weir is a waterproof membrane spread perpendicularly across the expected course of upstream flood water. The downstream edge of the membrane is attached to a buoyant tube, held back by anchored tendons. The tube rises under its own buoyancy, lifting the membrane to prevent water from flowing past. The Buoyant Weir can be designed for a desired “uplift" so that it will be known at which water level increase the Buoyant Weir will begin to overtop.
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Buoyant Weir in Tidal Setting
In a tidal energy as well as offshore flood protection setting the Buoyant Weir will operate in either direction from the tides and automatically rises and falls under different tidal water levels.
Image: The Buoyant Weir at high tide on flood current, with the tide flowing into an estuary or lagoon.
Image: At low tide on the ebb current.
Image: The weir on the ebb current, as the tide recedes and waters move away from the shore.
Image: At low tide on the flood current.
River and Inland Flood Protection
The Buoyant Weir can be used temporarily or permanently with VerdErg Renewable Energy's VETT-in-a-Box hydropower technology or Standard VETT system to generate electrical energy. The VETT-in-a-Box also offers the potential for airlifting ‘pop-up’ Buoyant Weir facilities to remote or disaster relief community locations.
Testing
Physical model testing was carried out at HR Wallingford in August 2023, successfully demonstrating the Buoyant Weir's operations.
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Image: Testing of the Buoyant Weir at HR Wallingford.