Final work on dam needs fine weather

A few more days of fine weather and the finishing touches can be put on Dannevirke's new $3 million dam.

A 170-metre by 130m addition to the Tararua district's water supply was to be completed by the start of next month, but recent wet weather may cause delay.

The dam, which is 46 times the size of an Olympic pool, had the first stage of work, which required about 180,000 square metres of material to be shifted, ticked off last month.

The second stage of installing the liner finished this month. But the final stage of putting a floating top liner to protect the bottom from sun damage, which stopped algae growth and birds defecating in the water, required more sunny days, Tararua District Council's manager of strategy and district development Peter Wimsett said. The materials to complete the floating cover were at the site and four more days of fine weather were needed to finish it off, pushing the deadline back to mid-June.

The "pretty impressive structure" can hold 115.7 million litres of water and has an extended water storage time of between 15 and 20 days.

Mr Wimsett said Dannevirke's two reservoirs could store water for only about 24 hours.

Pipework and controls enabling remote operation of the water supply have been installed.

The 12m-deep dam is designed to improve the reliability, availability and quality of the district's water supply. It will reduce the need for treatment by managing the intake during high river flows.

Mr Wimsett said that once construction was finished, filling it, which could take 15 days, should begin by the end of next month.

Manawatu Standard