The Lukely Brook is an important chalk stream that flows through Carisbrooke on the Isle of Wight, providing valuable aquatic habitat, supporting the ecology of Plaish Meadows which is designated as a Site of Interest to Nature Conservation (SINC), and acting as a key public amenity to local residents. Southern Water operates two licensed groundwater abstractions near to the Lukely Brook, which supply the Isle of Wight with clean drinking water.
Where the Lukely Brook flows through the more urban areas of Carisbrooke, the stream has historically been modified for access (ford crossings) and industry (water mills and ponds). Sluices, weirs and culverts constructed as part of these modifications and the resulting large jumps in water level can stop fish (and eel) from swimming freely up and down the stream.
In 2020, Southern Water either modified or replaced four of these historic structures so fish can now travel further up the Lukely Brook to Clatterford (around 1.3 km further than was possible before).Fish passes, sometimes called fish ladders, were installed within existing structures at Carisbrooke Mill and Southern Water’s Waterworks in Carisbrooke. A series of three small weirs were constructed below a culvert at Wellington Road, and the Garden Weir (behind Carisbrooke Road) was replaced with three small rock weirs creating a series of lower ‘steps’ that fish are able to swim up, especially when the flow in the stream is lower like in the summer.
In addition to removing these barriers to fish movement, Southern Water has also agreed with the Environment Agency to reduce the amount of groundwater they are allowed to abstract from the Chalk here. These changes were similarly implemented in 2020 and will make more water available to the Lukely Brook during dry summer periods, helping to protect the valuable ecology it supports.
On-going and future work
Southern Water are now (between 2022 and 2024) undertaking further river habitat enhancement work on the Lukely Brook between its source near to Bowcombe, down to Towngate Pond in Newport that will make the stream even more resilient to environmental change, improving flows and water depths in the stream, and providing increased public amenity value. Examples include cutting back bank vegetation to allow more sunlight into the channel, planting marginal aquatic plants, and redistributing gravel in the riverbed to create more variety in flow and water depths.