Lake salt fears

IRRIGATORS are concerned that a water management plan by the North Central Catchment Management Authority will lead to unacceptable salinity levels in Lake Meran.

This outcome would force them off the land adjacent to the lake, 22 kilometres south west of Kerang, and would create negative environmental outcomes, the farmers claim..

The Diversion Licence Holders Group, comprising eight irrigators, have expressed concerns that despite their families irrigating from the lake for generations, the new water plan, which involves a wetting and drying cycle, will make irrigating impossible.

In addition to that, the group claimed that salinity models had been left out of the original plan and were only included after they objected. 

Irrigator Stephen English said the community consultation group only had a day to approve the newly included salinity models in the plan.

"We ran our own salinity models but the catchment management authority never put them in until after the irrigators insisted. We got one day before the final meeting to approve the plan [occurred]," he said. 

"Then we became aware as to why the authority didn't want us to see the modeling," he said.

The salinity levels that will result from the new plan will at various times throughout the watering cycle be significantly higher than the current level of 889EC. 

The licence holders said that the new levels, which at some points will sit well within 2000EC, will make irrigating their Class A soil impossible, leaving them without an irrigation supply, and will create negative environmental outcomes.

Another concern the group has raised is that lake levels will be too low at some points for them to irrigate at all.

Irrigators have for some time been using water parcels for the environment to irrigate with when it the lake was plentiful.

However, the NCCMA's chief concern, and the only area over which it has jurisdiction in this issue, is environmental water.

Goulburn-Murray Water governs diversion licences and has stated that the lake falls under what is known as an unregulated diversion licence.

GMW's general manager customer operations, Scott Barber, said said that this means irrigators can take "opportunistic water" when it is available, but it has varying reliability.

"GMW is developing new Local Management Rules for Lake Meran to protect the water resources within the lake for domestic and stock purposes and environmental values," he said.

"LMRs help manage water levels by clarifying when diversions by individual licensed irrigators can take place," he said.

Under these arrangements, Mr Barber said if not for the NCCMA water plan, irrigators would not be able to irrigate at all.

"If there was no Environmental Water Management Plan in place for Lake Meran, the only water that would flow into the lake would be via natural overland flows or rainfall, also referred to as unregulated supply," he said.

"With the EWMP in place, the lake would potentially receive environmental water, which increases the reliability for irrigators. This is providing a regulated or controlled supply into an unregulated system," he said.

GMW cannot guarantee supply of water under unregulated licences. 

NCCMA program delivery executive manager, Tim Shanahan said that salinity levels will remain within acceptable levels for the environment.

"Currently the only managed source of water supply to the lake is from water for the environment. [That water] aims to improve the health and condition of the lakes' plants and animals, including fish and an important turtle population, by delivering the right amount of water at the right time, to supplement natural flooding and the natural wetting and drying phases of the region's lakes and wetlands," he said. 

"The salinity model shows that at the end of this plan in 10 years, by the time the water reaches its lowest level in the second cycle of watering, the minimum salinity level is predicted to be about 1880EC. The model does assume that diverters will be pumping water delivered for the environment at an even extraction rate of 3ML a day, whereas the reality is that diverters pump at fluctuating rates with peaks and troughs in volumes extracted," he said.

* FOR full story, read February 6's issue of the Gannawarra Times.

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