Local Govt | National News Video | Parliament Headlines | Politics Headlines | Search


Draining of water storage lake marks start of upgrade

9 September 2011

Draining of water storage lake marks start of upgrade

The draining of the southern Stuart Macaskill water storage lake at Te Marua has begun this week, signalling less stored water for Porirua, Wellington, Upper Hutt and Lower Hutt this summer.

The lake is being drained as part of Greater Wellington’s 2-3-year upgrade project to increase the resistance of the two Stuart Macaskill lakes to a major earthquake and boost their combined storage capacity by 13%.

Cr Nigel Wilson, Chair of Greater Wellington’s Social and Cultural Wellbeing Committee, says the upgrade is essential for a resilient, “future proof” water supply. (The committee’s responsibilities include water supply.)

“We’ve found that the lakes’ embankments may crack in a major earthquake, causing leakage and therefore slowing the recovery of our water supply system – seismic strengthening is a top priority to meet new dam safety guidelines. We also need to build more water storage capacity to serve our growing population.”

The upgrade works will require a lake to be empty this summer and the next – and possibly a third summer if there are any construction delays. This will essentially halve the amount of stored water available. And with one storage lake down, it’ll be harder to overcome water shortages in a warm, dry summer.

Cr Wilson says that Greater Wellington will be working closely with the Porirua, Wellington, Upper Hutt and Lower Hutt city councils to let the public know how we’re doing for water and provide simple tips on how people can help so that we don’t go short of water for essential uses. “If everyone works together and saves a bit more water, we can ease the pressure on our water supply and hopefully avoid tough restrictions.”


What’s the role of the Stuart Macaskill lakes?

Most of the treated bulk water that Greater Wellington supplies to the four cities comes from the Hutt, Wainuiomata and Orongorongo rivers and an aquifer, with the two Stuart Macaskill Lakes at Te Marua functioning as back-up to the Hutt River supply. Currently, each lake is 16 metres deep and together they have a capacity of approximately 3,000 million litres (ML), or enough to replace the average water supply from the Hutt River for about 50 days.

The lakes are filled from the Hutt River when the water is clean and there is plenty available. Stored water is pumped back to the water treatment plant when there is not enough water in the Hutt River to meet public demand, when the river is too dirty or when it is in flood and the intake is closed to prevent rocks and gravel from entering the intake pipes.

What will the upgrade involve?

The southern lake will be empty this summer (2011/12) and the northern lake empty in summer 2012/13. If there are any delays a lake may need to be empty in summer 2013/14.

Seismic strength will be increased by:

• Installing a strong, flexible liner in the lakes, which can stretch to more than seven times its length. This should prevent leakage after an earthquake even if the soil beneath the liner cracks

• Buttressing of the lakes’ external walls

Storage capacity will be boosted by:

• Raising the lakes’ walls by one metre to give an additional 400 ML (13%) combined storage capacity. That’s enough to help maintain supply for up to two weeks longer in a drought, in combination with other water sources.

• Tenders for the lakes’ upgrade are currently being considered. The lining and embankment raising works are expected to start in November.


Visit Greater Wellington’s website for a live water supply map, including a daily update on how much water Greater Wellington is supplying to the four cities: www.gw.govt.nz/live-water-supply .


© Scoop Media

Parliament Headlines | Politics Headlines | Regional Headlines

Gordon Campbell: On Budget 2022

At base, the political biffo back and forth on the merits of Budget 2022 comes down to only one thing. Who is the better manager of the economy and better steward of social wellbeing – National or Labour? In its own quiet way, the Treasury has buried a fascinating answer to the “who’s best at running an economy during a crisis?” question, at page 57 of the Fiscal Strategy section...


Government: Helps Supermarket Shoppers Get A Fair Deal
Urgent Budget night legislation to stop major supermarkets blocking competitors from accessing land for new stores has been introduced today, Minister of Commerce and Consumer Affairs Dr David Clark said... More>>

Budget 2022: A Secure Future In Difficult Times
Budget 2022 will help build a high wage, low emissions economy that provides greater economic security, while providing support to households affected by cost of living pressures... More>>


Budget: Climate Investments Provide Path To Economic Security
The Government is investing in New Zealand’s economic security by ensuring climate change funding moves away from short-term piecemeal responses and towards smart, long-term investment... More>>


National: Jacqui Dean To Retire From Parliament In 2023

Waitaki MP Jacqui Dean has announced that she will not be seeking re-election at the 2023 election. “I have advised the President and Leader of the National Party that I have decided not to put my name forward... More>>

Classification Office: Following Decision To Ban Manifesto The Buffalo Mass Shooting Livestream Is Now Banned
The livestream video of yesterday’s mass shooting in the United States has now been banned, Acting Chief Censor Rupert Ablett-Hampson announced this morning. The decision follows on from his decision yesterday to call in and ban the ‘manifesto... More>>

Borders: New Zealand Poised To Welcome International Students Back
New Zealand is fully reopening to international students and the Government is committed to help reinvigorate and strengthen the sector, Education Minister Chris Hipkins said today... More>>




InfoPages News Channels