Hydro Lakes Recover

Hydro-electric storage lake levels improved dramatically during the latter half of November.

At the beginning of November, national hydro lake storage stood at 2297 Gigawatt hours (GWh) or 94% of average, continuing a trend that has seen lake levels consistently below average during 2006.

Whilst daily storage figures for November were above those for November 2005, they still remained below overall average levels until November 14th when twice normal inflows boosted storage. The hoped-for improvement in storage arrived late, following a cool spring which slowed snowmelt and increased electricity demand.

Above average inflows continued boosting storage until November 27th when they eased back briefly. Water flowing into the lakes increased again on the 29th, and a whopping 293 GWh of inflows, 350% of average, was recorded on the 30th.

Steady rain in lake catchments nationwide was a key component in the improving lake levels, with the inevitable downside being the increased risk of flooding. Lake Wakatipu, which normally benefits from melting snow and rainfall during spring, rose rapidly from the middle of the month, threatening to flood Queenstown. The lake reached 310m, close to the level at which flood alerts are issued, its highest level since the 1999 flood which caused 3 weeks of disruption for the town.

At the end of November 2006, hydro storage stood at 3495 GWh, a healthy 132% of average.

[Compiled from data supplied by M-co.]

Leave a Reply