Waimak dam up­set con­tin­ues


Op­po­si­tion to a 13-me­tre high dam in the Waimakariri dis­trict con­tin­ues, de­spite it be­ing out of the lime­light for a cou­ple of years.

Cather­ine Ballinger of the Eyre Community En­vi­ron­men­tal Safety So­ci­ety (ECESS) res­i­dents’ group said although the mat­ter had been be­fore the En­vi­ron­ment Court for the past two years, many peo­ple were un­aware of the group’s ef­forts, which was why she wanted to ‘‘ring the bell again’’ and rally the troops.

‘‘We need the whole community be­hind us,’’ she said. ’’We want to do some fundrais­ing and get our voice heard again.’’

In essence the group is op­pos­ing Waimakariri Ir­ri­ga­tion Ltd’s (WIL) build­ing of a large dam on the grounds of safety con­cerns. With about 1,800 peo­ple now liv­ing down­stream of the pro­posed dam, Ballinger said res­i­dents were con­cerned about the lack of a work­able evac­u­a­tion plan.

‘‘Noth­ing has been built like this be­fore, with no nat­u­ral wa­ter course for it to flow to if it breaks or floods,’’ she said. ’’The only course of ac­tion we could take was to ap­peal, which we are do­ing now.’’

Ballinger said pub­lic meet­ings had been held with WIL and GNS sci­en­tists at­tended by ‘‘lots of un­happy peo­ple’’.

Con­cerns were height­ened af­ter last year’s earth­quake, she said, how­ever there had been no change to the dam plans to take a po­ten­tial nat­u­ral dis­as­ter into ac­count, de­spite build­ing stan­dards hav­ing been changed in re­cent years.

‘‘We are not anti-dairy­ing, and we are not against wa­ter stor­age. It’s just the safety is­sues. There are other al­ter­na­tives — farm­ers could put their own ponds in, un­der­ground stor­age could be put in. By all means have your wa­ter, but store it safely.’’

WIL gen­eral man­ager Brent Wal­ton said there were cer­tainly some farms which al­ready had on­farm stor­age, how­ever the dam was nec­es­sary to pro­tect against the rav­ages of drought.

Cur­rently farm­ers in the area had a 75 per cent re­li­a­bil­ity on be­ing able to take wa­ter, but for the re­main­ing 25 per cent of the time the Waimakariri River level was too low and restrictions came into force.

With the dam, this re­li­a­bil­ity would be up be­tween 92 and 95 per cent, he said.

Al­ter­na­tive sites had also been re­searched, but there would al­ways be a pop­u­la­tion be­neath any pro­posed dam.

As for the safety con­cerns, four dif­fer­ent flood sce­nar­ios had been mod­elled. While the ECESS group ar­gued they would not hear warn­ings over loud speak­ers or sirens, the mod­el­ling showed there would be plenty of time for an evac­u­a­tion.

The wa­ter would take at least two and a half hours to reach Downs Rd, and a fur­ther two to five hours to reach Two Chain Rd.

In the event of a ma­jor earth­quake, which was the only re­al­is­tic risk to the dam’s struc­ture, the quake it­self would be the trig­ger for the area to evac­u­ate, Wal­ton said.

In terms of a fault with the struc­ture, there was a three-tier emer­gency man­age­ment plan with checks and bal­ances in place, in­clud­ing weekly in­spec­tions, wa­ter level checks and seis­mic trig­gers.

The de­sign of the dam, which would be built to the high­est stan­dard, had been ex­ten­sively peer­re­viewed.

In ad­di­tion, it was im­por­tant to note there were share­hold­ers in the ir­ri­ga­tion scheme liv­ing in the flood path who would be un­likely to be in­vest­ing if they be­lieved it was go­ing to burst in five years, he said.

The next step in the process was for the mat­ter to take its course in court, with a hear­ing an­tic­i­pated be­fore Christ­mas, he said. Af­ter that, a con­struc­tion con­tract and price would be ne­go­ti­ated be­fore it went to the share­hold­ers for ap­proval. Only then would con­struc­tion go ahead, Wal­ton said.

Cather­ine Ballinger of ECESS is con­cerned about evac­u­a­tion plans.

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