The pretty Northampton villages around Weedon, in the upper River Nene valley, suffered disastrous flooding in 1998, with Weedon Bec being particularly affected.
To alleviate this problem, the Environment Agency (EA) has put into place a dam project to contain floodwater in the catchment area, of which the key component is a 6.5 ton, 2 metre diameter Hydro-Brake® Flow Control device located in the dam, supplied by Hydro International.
Contractor Edmund Nuttall created an embankment across the valley, using locally won blue clay as the embankment core topped with a granular hogging layer, with a centrally located concrete culvert to channel the water flow.
Environmental sensitivity of any flood control solution was a crucial part of the scheme and the EA has made an arrangement with local farmers to allow their fields to flood behind the day during heavy rainfall to avoid damage downstream.
By using a Hydro-Brake® Flow Control at the inlet to the culvert, the EA provide a controlled maximum flow of water despite a fluctuating head, with a designed maximum flow of up to 12,000 l/s. The operating characteristics of the Hydro-Brake® Flow Control allow for a dramatic reduction in land take due to a reduced requirement in storage capacity.
The design work carried out by Hydro International prior to manufacture of the Hydro-Brake® Flow Control included incorporation of an adjustable intake to allow future adjustment of the flow rate either upwards or downwards between 8,000 l/s and 12,000 l/s.