days bay.
Photo: RNZ / Angus Dreaver
Wellington’s water utility hopes to start excavation at the site of a broken sewage pipe at Eastbourne Harbour in Lower Hutt on Monday morning.
Since the main sewer line next to the pumping station in Days Bay burst on Saturday afternoon, both treated and untreated sewage has been entering the harbor.
Flooding has also forced the closure of three public beaches at Days Bay, York Bay and Sunshine Bay, and local iwi are considering a rāhui.
Repairs are expected to take several days and Eastbourne residents are being asked to flush toilets less and avoid long showers to save water.
Jeremy McKibbin, Wellington Water’s head of network management, said it was not a simple leak and that repairs would require releasing more wastewater into the harbour to empty the pipe.
There are several sewage pumping stations in the immediate vicinity, he added.
To reduce water flow and increase safety for repair crews, the main sewer line to Pencarrow Heads was also closed. As a result, treated sewage was discharged into Waiwhetu Creek.
McKibben said the cause of the fracture could not be determined until excavations began.
However, he said initial investigations had found that two valves near the leak may have been affected.
“One valve connects the pumping station to the pressure main that returns the water to Seaview’s sewage treatment plant for treatment; the other valve is connected to the main discharge main that takes the treated wastewater to Pencarrow. Two different valves connect two different parts of the network.”
The repair was “extremely complex” because it was a “difficult installation situation”.
“It’s quite deep and in the intertidal zone, so once you dig down there, it’s affected by the tide, it’s also affected by the main drainage pipe – the sewage in there – we actually have to drain it because it’s quite a large volume.”
McKibben said Wellington Water was aware of the impact the incident had had on the environment and recreational users in the area.
“That’s why we’re working on the repair as quickly as possible.”
Crews had been working “at full speed” all weekend and into Sunday night, with trucks driving back and forth to transport raw wastewater to the Seaview treatment plant.
To reduce the amount of water entering the port, the water was collected at two pumping stations.
McKibben said the main drainage pipe in Days Bay was in “pretty bad” condition.
“We have problems with this pipeline on a fairly regular basis. It’s a very expensive piece of infrastructure that needs to be replaced. It’s part of the long-term plan, but that’s going to take a while.”
