The Winchester Garrison Grounds Flood Alleviation scheme focused on addressing long-standing surface water drainage issues within the south-western corner of the Garrison Grounds, an area prone to waterlogging during periods of heavy rainfall. The works involved the construction of a series of new land drains designed to intercept and manage surface water, connecting into the existing drainage network which outfalls to the River Itchen via a large underground carrier pipe. The new drainage system was integrated with the existing watercourse running along the boundary of the Garrison Grounds and included the installation of manholes, inspection chambers, traps, and separators. The scheme has significantly improved drainage performance and resilience, reducing flood risk and enhancing the usability of this important open space.