Underground Service Locating in Thames

Thames sits where the Coromandel Peninsula meets the Hauraki Plains, strung along the eastern shore of the Firth. The town grew quickly in its gold-mining years and much of what stands today dates from that era or the decades after it, including a long run of heritage commercial buildings on the main street and plenty of older timber housing behind them.

The ground changes sharply across town. The flat land towards the Firth and the plains is soft alluvial material with a high water table, while the streets climbing the hills behind are on steep, rocky ground. Water and wastewater are run by Thames-Coromandel District Council, and the mix of old pipe and variable ground keeps leak and locating work interesting.

Thames is a long way from most Auckland contractors, and that distance is the point. Utility Works arrives with locators, hydro-vac truck and digger on the same trip, so a job that would otherwise mean three separate visits from three separate trades is handled in one. We group Hauraki work into runs so the travel is never wasted.

Thames has some of the oldest pipe anywhere in the region. Under the 1870s to 1920s streets on the flat we expect galvanised steel laterals, some close to a century old, off cast iron mains with lead joints, with asbestos-cement where mains were renewed mid-century. Galvanised that age is more rust than steel, so leaks are pinholes and split threads and a lateral can be leaking in two or three places at once. Lead-jointed cast iron weeps at the joints whenever the ground moves.

On the hill streets the lines are younger and shorter but run steeply, so a leak surfaces well downhill of the pipe. Moanataiari and the post-war infill carry copper and early PVC, and anything from the 1990s on is MDPE without a reliable tracer wire. The practical result is that most Thames pipe is metal and traces well, but it is fragile, so we expose it with hydro-vac rather than a bar, and we expect abandoned lines from earlier buildings on the same lot. Under Pollen Street the services are layered a century deep, and the plans stop short of the shop.