The Hurunui Water Project plans to raise the level of Lake Sumner by two metres for an intensive irrigation scheme that will enable dairy farming expansion in the area.
Canterbury resident, Edward Snowden, said the proposed run height would mean that Lake Sumner and nearby Lake Katrine, would lose forest cover along 70 percent of their perimeters.
“The lake foreshore of this popular swimming beach will be submerged in summer under the Hurunui Water Project regime,” he said.
Undemocratic legislative change
Last year, the Environment Canterbury board was sacked by the Government, and new un-elected Commissioners appointed using legislative changes pushed through under urgency. Canterbury groups such as “Our Water, Our Vote” and “Save our Water” suspect that similar undemocratic legislative changes will be made to ensure the changes to Lake Sumner.
At a Hurunui Water Matters meeting in central Christchurch (in February 2011, organised by “Artists for Save our Water”), it was revealed that Environment Canterbury’s Zone Committee meetings want the Waiau flow and allocation to be decided by February and the Hurunui flow and allocation done by March.
In a report from a Hurunui Zone Committee earlier this year, (on January 31st), the briefing by EC principal consents and planning officer, Lynda Weastell-Murchison, advised the Hurunui Zone Committee that it could find its “own integrated solution” and that “if the law won’t let us at the moment, so we can find another way, legislative change”.
Professor Philip Joseph from the University of Canterbury’s School of Law, said that the “Environment Canterbury (Temporary Commissioners and Improved Water Management) Act” that was passed under urgency last year, breached several principles of law, and was “constitutionally repugnant.” He said the legislation contained “elements of subterfuge” and was a “constitutional affront”, since the public has lost the right of recourse to the Environment Court.
Proposals to raise lake levels
Proposals before the Zonal Committees include; a dam at Lake Sumner and a 75 metre dam at the south branch of the Hurunui; Ngai Tahu Property proposed raising the Lake level 2.35 metres with an in-canal hydro at Balmoral; transferring water from the Hurunui River by pumping it 70 metres to a canal and tunnel through to the upper Waitohoi River to be stored in a 100 metre dam near Seven Hills; pumping water from the Waiau River from a canal to a reservoir at Grampians or to a large storage in the upper Pahau; a dam and reservoir on the Mandamus River with water pumped from the Hurunui River; a new race to supply Waiau river water to the Balmoral Forest. (Ngai Tahu received this forest in their Treaty Settlement and now wishes to clear fell the forest and convert it to dairy); and pumping water from the Waiau River to a reservoir at Countess Stream.
Two further confidential options were presented to the committee that the public was excluded from hearing about. The Zone Committee was concerned that Hamner Basin was missing out on the economic benefit of having its river “managed”.
Huruanui District mayor Winton Dalley, made the point that “if the add-on costs of weed and predator control were too great, a partnership with the greater community would be needed.”
In other words ratepayers could be expected to pay for the proposed, grandiose despoiling of pristine wild rivers, said David Bedford. He pointed out that missing from the list was having a good public supply of water, and that the Hurunui zone committee did not have the science or funds to make these decisions at this stage.
Inundation six months of year
Ecologists for the Hurunui Water Project have reported that the raising of Lake Sumner’s level will most likely happen for only one to three months of the year, but earlier reports have shown possible inundation for three to six months of the year.
In the report on ‘Lake Sumner Water Storage and Edge Inundation’, by consultants Boffa Miskell, the ecologist said that to store water for irrigation use it was proposed to build a low control gate at the outlet of Lake Sumner.
This mechanism would be used to hold the lake level higher than the present average, but would not exceed the natural range of the lake and would cause an average increase in lake height of between 0.75m and 1.4m during the irrigation season.
The effects of the proposed additional inundation of Lake Sumner on lake edge vegetation and habitat would include the loss of beech forest, wetlands, and kowhai forest, as well as smaller areas of matagouri shrubland and native forest, from around the lake.
Loss of vegetation communities
The report said the main potential adverse effect was the loss of some or all of the lower-beach kowhai - coprosma communities.
“Even with tolerances of over 90 days inundation it was likely that most in the current typical beach vegetation fragments would eventually die.”
The lake margin increase under the proposed storage regime would affect the beach growing herbaceous vegetation, (a narrow band up to 2m wide in some locations), kowhai and broadleaf raised margins, brown top dominated grasslands, and a small area of Schoenus wetland in the Loch.
“The margin will still present as a native intact riparian vegetated margin, if with less frequently evident beaches,” according to the ecologists‘ report.
References
- Artists for Save our Water meeting in Christchurch, Sunday 20th February 2011
- Artists for Save our Water website
- Our Water, Our Vote website
