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Greater Wellington Regional Council is urging people in the region’s four cities to remain careful with their water use over the next few months after a “dry” December in the Hutt water collection area, in spite of the heavy rain at the end of December.
Although the level of rainfall at NIWA’s Kelburn monitoring station was well above average last month, Greater Wellington’s Hutt Water Collection Area rain gauge at Kaitoke recorded just 70% of the ‘usual’ level for December – the fifth month in a row of below average rainfall in the water supply catchment area.
“We still have one storage lake empty for upgrading and less rain than usual for this time of year in the headwaters of the Hutt River so we need to remain focused on making water savings where we can,” says Cr Sandra Greig, Deputy Chair of Greater Wellington’s Social and Cultural Wellbeing Committee.
“January and February are typically the hottest, most settled months of the year. It’s also the time when water use usually peaks, with increased garden watering being a big contributor to surging supply levels. The combination of these factors, along with an empty water storage lake and low Hutt catchment rainfall, means that the ‘dry’ summer we’ve been talking about is here.”
Cr Greig says that the dry spring in our water catchments may seem like a distant memory, but it’s had an affect on water supplies, leaving less water in the Hutt River than would be ideal.
“If people make just a few simple changes to their water use, it will help to reduce the chance of harsh watering restrictions and take pressure off the Hutt River. Easy measures to use a bit less, such as targeting garden watering so that you only water your plants’ roots and turning the tap off while you brush your teeth, can make a big difference and leave enough water to see us through summer.”
“People should also be vigilant for water leaks, which can show up more easily in dry conditions. Wet spots on road frontages and water running down street gutters can often be due to leaks. Please phone any information about possible leaks in to your city council, which will investigate these and repair them if necessary,” she says.
Greater Wellington and the Porirua, Wellington, Lower Hutt and Upper Hutt city councils are kicking off the summer phase of their water conservation campaign next week with “do it now” water saving tips. This follows the “get prepared” phase which took place in spring 2011.
Visit www.gw.govt.nz/water for summer water-saving tips, water situation updates and information on Greater Wellington’s lakes upgrade project.
For details of the current watering restrictions in your area, contact your local city or district council.
Rainfall and water source data
December 2011 river flow rates and aquifer level (percentage compared with the long-term December average for each site)
Hutt River at Kaitoke (flow) – 70%
Wainuiomata River (flow) – 114%
Hutt aquifer (level) – 102%
The Hutt River at Kaitoke typically provides just over 40% of the total water supply for Upper Hutt, Lower Hutt, Porirua and Wellington. The Hutt aquifer, which is fed by the Hutt River, also provides about 40% of the total water supply.
Background to lakes’ upgrade
Greater Wellington supplies bulk water to Porirua, Wellington, Upper Hutt and Lower Hutt. The water comes from rivers and an aquifer, backed up by the Stuart Macaskill storage lakes.
The Stuart Macaskill water storage lakes are being upgraded to increase their strength in an earthquake and to boost storage capacity. Much of the work requires the lakes to be empty and dry working conditions, which is why we’re doing it during summer. The southern lake is currently empty with work on it likely to finish in mid-2012. The northern lake will be empty during summer 2012/ 2013. If there are any delays, a lake may be empty during summer 2013/14.