12 June 2012

Wivenhoe Dam back to high levels


WIVENHOE Dam has been allowed to reach its highest level since February 2011, with steady flows lifting the massive water supply well beyond the 75% maintained during the summer wet season.

SEQwater figures from last Friday showed the dam was now more than 85% full and rising slowly as a result of the relatively light rain that hit the area last week.

The dam has been on a steady rise since measures to rein it in were relaxed in mid-March.

The previous State Government made the decision to drain Wivenhoe to 75% of its full capacity at the end of last year following pressure from flood victims and the then LNP opposition.

Before that, the dam level had been maintained at 80%.

A change in State Government could lead to a change in policy for the way south-east Queensland's dams are managed. An SEQwater spokesman said the new State Government was in the process of reviewing dam management practices - in particular the levels that will be maintained during the summer storm season.

"For now at least, the dam will be allowed to return to its full supply level," the spokesman said.

"The new Government is reviewing the levels and how they will be maintained in the future."

At this stage it is uncertain whether the LNP Government will drain Wivenhoe Dam back to 75% at the end of this year.

The previous government's decision to leave Wivenhoe at 100% leading into the floods in January 2011 was blamed for reducing the dam's flood mitigation capabilities.

Lake Wivenhoe reached 190% at the peak of the floods, with water lapping just 60cm below the auxiliary spillway.

This necessitated the steady release of water down the Brisbane River during the flooding to prevent what would have been an even bigger catastrophe. In a week-long period between January 12 and January 20, last year, 90% of the capacity of the dam - close to one million megalitres - was released down an already flooded Brisbane River.

As of last Friday, Wivenhoe Dam was one of the few storages on the south-east Queensland water grid that was not full or overflowing.

In fact, 10 out of the region's 24 major dams are currently spilling.

Eleven of the remaining 14 are either 100% full or just under, including Somerset Dam, which is 99.6% and North Pine Dam, which is 98.4%.

http://www.qt.com.au/ 

12.6.12