Flows from Nymboida weir are topping up Karangi Dam.
Flows from Nymboida weir are topping up Karangi Dam.

Nymboida is topping up Coffs water supplies

KARANGI Dam is being topped up with gravity flows from Nymboida Weir as water levels continue to drop in the Orara River.

Karangi Dam, which supplies Coffs Harbour's water, is at about 93% capacity thanks to these injections of extra water.

Coffs Harbour City Council's director of city infrastructure services, Ben Lawson, said they would probably think seriously about Level 2 water restrictions if Karangi Dam dropped to about 85% capacity, but it depended on the forecast and other factors.

"Based on current water usage and assuming no rain, it would take about five weeks to reach 85%," he said

The 28.4mm recorded in Coffs Harbour on October 19 has made little impact on the dry conditions affecting the city, which had previously recorded only four days of rain over 5mm in the past four months.

The Orara River is the lowest it has been since mid-January, although river flow is still 30ML per day.

Orara river flow was down to 0.5ML/day during the last protracted dry spells in 2002 and 2003, but in some earlier dry years it has recorded no surface flow at all.

Shannon Creek Dam, which provides water security for both Coffs Harbour and Grafton water supplies, is at 93.8%, holding 28,042ML.

Coffs Harbour's current daily rate of usage is 16.8ML, better than the council's daily target of 18ML.

Coffs Harbour has had permanent Level 1 water restrictions since 2004. These rules ban fixed hoses and sprinklers between 8am and 4pm; restrict building maintenance using water to trigger nozzle hoses or pressure washers, and restrict washing of driveways, roofs and pavers to health and safety reasons only.

Since Shannon Creek Dam was completed in 2008, the city has had a secure water supply and a succession of wet years, but previously tight water restrictions were a regular feature of life in Coffs Harbour.

In 1994, before the wall of Karangi Dam was raised by 10m, for more than seven months residents were forbidden to use any water outdoors. Even after the wall was raised, it was buckets only outdoors for three and a half months in 2002 and the city had a full year of water restrictions.

Shannon Creek Dam, which holds 30,000 ML when full, was completed in November 2008 and water restrictions have remained at Level 1 since, while flooding has been much more of a concern to local residents than drought.