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Rivers Team Protect Us From Rare But Real Risk

Thursday 22 September 2011, 2:13PM

By Marlborough District Council

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MARLBOROUGH

The Council’s Rivers team plays a vital job in keeping the urban and rural properties of Marlborough safe by managing the rivers that criss-cross the Wairau Plain – the floodplain on which we live.

Millions of dollars have gone into flood control works constructed and maintained by the Council (and its predecessors) over the last hundred years or more. Remember, the Wairau is bigger than Canterbury’s Waimakariri River, with a 15% greater flood flow to be contained. In the past, that flow has had devastating effects on human life, livestock, crops, buildings and essential services.

The Rivers team keep a close eye on the state of our rivers; always monitoring their flood-carrying capacity, keeping back the willows that threaten river flows and stabilising riverbanks with a combination of rocks and planting, including native plant species.
The Rivers team recently inspected the lower reaches of the Opawa River and Wairau River to check on sediment build up and the need for river bank protection maintenance work.

Hand-in-hand with flood control is drainage maintenance. More than 8000 hectares of productive land at the eastern end of the Wairau Plain relies on the Council maintenance of 150 kilometres of watercourses and drains, and 18 pumping stations. A further nine pump stations ensure that stormwater from Blenheim can drain away when river flows are high.
Council knows it must keep all drains in good condition to cope with sudden heavy rain - so there can be no let-up in maintenance. Controlling the aquatic weed in our waterways is also a constant battle and we’re now spending more than $100,000 a year on the weed control programme.

Landowners and residents can play a part by keeping canals, waterways and stormwater drains on their own land clean and flowing freely, remembering that where pressure builds up, the river forces its way into new courses.