Flooding of properties in the low lying Sulphur Beach catchment is exacerbated by high tides and storm surges. In order to reduce these flooding occurrences it was proposed to install 2 large dia Wastop non return valves to prevent back water from the Waitemata Harbour surging into the piped network.
In order to install the Wastop valves some physical stormwater works were required. A large outlet structure was removed together with a 1050dia concrete pipe and replaced with a new outlet structure and Wastop valve installed in the existing pipe. A further 600 dia Wastop valve was installed at another outlet within a manhole.