GPR Scanning in Pōkeno

Pōkeno has gone from a small rural stop on State Highway 1 to one of the fastest-growing settlements in North Waikato. Large residential subdivisions have spread across the hills around the old village, and industrial and food-processing operations have set up on the flat land near the expressway.

That growth means a great deal of new underground infrastructure laid in a short time, and not all of it is recorded accurately. The hilly ground is mostly clay, which holds water and can carry a leak some distance downhill before it shows on the surface.

Reticulated water and wastewater are managed by Waikato District Council. Outside the subdivisions, lifestyle blocks and farms rely on bores and tanks, and many have older private lines that pre-date the recent growth. We reach Pōkeno quickly via the expressway from Waiau Pa.

Pōkeno turns the usual Franklin story on its head. There is almost no old pipe to worry about: the handful of village houses on the old highway may still have galvanised laterals, and the lifestyle blocks on the surrounding hills run alkathene from bores, but the town itself is PE100 and PVC with tracer wire, laid since about 2012.

The trouble is how it was laid. More than 1,500 houses went up in a decade on cut-and-fill lots across the hills, with a different contractor on every stage. We find laterals crushed where a retaining wall footing went through them, tracer wire severed at the boundary so the plastic line is invisible to a locator, tobies buried half a metre under imported fill, and services sitting at odd depths where a lot was cut down or built up after the mains went in. New pipe, old problems. Radar and the hydro-vac do most of the finding here.