Pond maintenance keeps stormwater harvesting scheme ready for use

Orange Council

This week, local specialist contractors Blackpoly Piplelines are working to maintain Orange’s stormwater harvesting scheme, as Orange City Council gets the system ready to be used in the coming months.

A floating dredge and a heavy-duty pump, that is used in the mining industry, is pumping sediment out of ponds that are part of the scheme.

Orange Deputy Mayor, Gerald Power said it was important to keep the system working well.

“When we need it, our stormwater harvesting scheme can deliver a quarter of our city’s water needs, so it’s important to keep it operating smoothly,” Cr Power said.

“Taking a metre of sediment off the base of the pond doesn’t increase its volume by much. It’s more a step that delivers better water quality by giving the sediment, settling out the water, somewhere to go.”

When water is pumped from Orange’s stormwater harvesting wetlands to add to Suma Park Dam, it first flows into a holding pond before going through two sedimentation ponds.

In the two ponds, which each hold 17 megalitres, the stormwater is tested and treated to remove impurities like sediment. A water treatment is added which helps the sediment settle out of the water and onto the base of the pond.

“Over the years, sediment has settled and built up on the floor of the pond. It’s estimated to be around a metre deep, and this week a specialist contractor is working to remove that mud,” Cr Power said.

“From the pond, the mud is pumped up a small hill and captured in a huge mesh bag which filters out the sediment, leaving clear water that flows back down hill to another pond.”

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