Hydro Lake Storage Still Below Average

Weekly inflows to New Zealand’s hydro storage lakes were erratic during June, being below average during week 1, above average for weeks 2 and 3, and below average during the last week of June. This trend continued into July, with inflows being 82% of average in the week ending July 7th.

Despite this, lake inflows remained above those for the dry years 1992 and 2004.

Lake storage levels remained below average throughout June, lower than or on par with storage levels recorded in 2004. During the month, hydro lake storage remained well-above 1992 levels which reached their lowest level of less than 1000 GWh during the first week of July 1992, resulting in power blackouts.

At July 7th 2006, hydro-lake levels stood at 82% of average storage, at 2158 GWh.

Hydro lake levels generally fall until mid-September, when warmer temperatures reduce demand and spring thaws provide increased in-flows to South Island lakes.

Lake inflows during 2004, the most recent year that caused serious concerns for continuity of supply were often above average during the first 6 months of the year, as opposed to this year when the 4 peaks of above average inflows have been lower.

This leaves New Zealand’s hydro storage with an on-going deficit of below-average storage for 2007. High inflows during spring will be crucial to restore water levels for next year.

[based on data supplied by M-co.]

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