In early 2020, Cain Bio-Engineering, on behalf of the client Thames Water, completed the construction of a fish pass at Venn Mill on Childrey Brook in Oxfordshire. The existing weir infrastructure was identified by the Environment Agency as a ‘significant barrier to fish passage’.
The weir was lowered by 300mm and a series of five concrete baffles installed downstream to manage the head-drop between the mill leat and bypass channels. The baffles each incorporate a low flow notch, capable of operating in a range of flow conditions. The fish pass was dressed with gravel, to create further habitat enhancement.
Not only is the final installation fish passable under most flow conditions, but also maintains the existing flow regime and allows for continued function of the mill.