Reservoir type access cover with sampling access. This design of lid was fitted to reservoirs from about the the 1980s. It was lighter than a cast iron lid and easier to lift with a hinged design and lifting handles. It fitted over a a raised flange casing which helped prevent surface water and rain ingress into the chamber below. It incorporated a smaller and very light to lift lid for the water quality staff to lower a water sampling container into the water below.

Photo taken 2022