The Macalister Irrigation District is the largest irrigation district in the south of Victoria. The district has secure water supplies supplemented by good rainfall, productive soils, a strong dairy sector and developing vegetable and cropping industries. Estimates put annual economic contribution in excess of $500 million per annum.
More of the designated irrigation district could be used for food production; however, further investment is needed as increased production is constrained by a shortfall of water to meet available irrigable land and an antiquated supply system that provides poor service to most customers. This poor service means that best practice on-farm water use and farm productivity cannot be achieved.
The district can be modernised to contemporary standards through a combination of pipelining and channel automation at a cost of approximately $310m (2011 dollars). This would provide an additional 37 GL of water for irrigation use through reduced water losses and provide excellent service to customers, allowing a similar or greater amount of water to be saved on-farm. Bulk inflows to the Macalister Irrigation District in 2009-10 were 201.9 GL.
Southern Rural Water is proposing a co-funding investment model with government funding 50% of the investment, and irrigators the other 50%. Water savings would go back for use within the irrigation district. Discussions were held with the Victorian Government on this basis.
Initial estimates showed the price rise for this investment is beyond the irrigators’ capacity to pay at this time. Therefore, Southern Rural Water proposed to break the project into two phases. The first phase would focus on work which brings the greatest value in water savings and service improvements.
The estimated cost of the first phase is $122.8m (2012 dollars).
- pipelining of one full supply zone
- further automation of channel regulating structures in three zones
- constructing a balancing storage
- some outlet modernisation and rationalization
- establishment of at least one end-of-drain wetland.
Southern Rural Water sought a government contribution of $61.4m. A business case was submitted to the Victorian Government on this basis.This would fully modernise 40% of the district, provide some service benefits to a further 85% of the district and create 26 GL of water savings for use back in the district.The expected regional economic growth from the Phase 1 investment is approximately $80m per annum.
In May 2013, the state government announced it was providing $16m towards the modernisation of the MID, with a co-contribution of $16m from Southern Rural Water.The works to be done over the next three years include:
- upgrade of regulators in:
- all of the Nambrok-Denison supply system
- most of the channels in the Eastern system
- all of the Heyfield channels
- construction of the Southern Cowwarr balancing storage in Nambrok;
- further expansion of our outlet rationalisation and modernisation program
- detailed design of the $80m (approximately) Southern Tinamba pipeline for further funding submissions down the track.
We estimate that this suite of works will save around 12,300ML. We expect that most of this water will be offered to customers by distribution in proportion to their entitlement. Some water will be offered for sale via auction and/or a shelf price.
Some of the other benefits include:
- modernised systems for two more supply zones – about 70% of the districts channels will be modernised by the time these works are finished
- reduced times between orders and delivery in modernised areas along with less shifting of orders
- on-farm benefits for modernised outlets including more consistent flow rates and higher flow rates
- reduced outfalls meaning less drain flows out of the district and therefore reduced nutrients heading down to the Gippsland Lakes
- better asset conditions to carry the district into the next 40 years
- Improved safety by removing manual handling of regulator drop bars
MID Supply Zones
For the purpose of MID 2030 the MID has been slip into five zones that align with the natural boundaries. The soil permeability profile varies significantly between each of the zones.
The following table and map shows the zone and highlights its colour code:
Southern-Cowwarr Balancing Storage
The nature of the Main Southern Channel does not allow for the implementation of full Total Channel Control (TCC®) due to legacy issues associated with the long distance from the Glenmaggie dam and Thomson River and the lack of control on the Cowwarr channel. The Eastern Irrigation Business has identified the storage basin as a high priority project from MID 2030 suite of projects with respect to customer service outcomes and outfall reductions. Construction of the storage has the ability to improve customer service in the Southern Main, the Southern-Tinamba, and the Southern-Cowwarr Supply Zone. It is estimated that the balancing storage could save approximately 1,700 ML/annum in outfalls.
Based on the final design the estimated construction cost for the storage is $5.84m compared with $6.4m originally estimated from the preliminary design.
Southern-Cowwarr Regulator Retrofit Program
Under the Southern-Cowwarr Regulator Retrofit Program Southern Rural Water plans to modernise approximately 179 regulators in Zone 4 (Nambrok-Denison) of the MID. The works will be completed over the 2014 and 2015 winter maintenance periods.
The total capital cost of the proposed project is estimated at $11.2m. In return, the project is expected to produce water savings of 4,075ML as well as improved levels of customer service.
Southern-Tinamba Pipeline Design
The Southern-Tinamba Pipeline Design Project is a component of the MID2030 Phase 1A Program.
The objective of the project is to develop a “shovel ready” pipeline design for the first stage of the network and a preliminary design for the remainder of the network. This project is due to be complete at the end of 2014 at a capital cost of $1.4m. This investment will help drive further funding for this part of the MID.
- the conceptual study review has been completed
- final versions of Flora & Fauna and Cultural Heritage Review Reports have been received
- the Concept Design Review Report has been issued to SRW
- the preliminary design has commenced
- rationalisation opportunities have been identified and communicated to the consultant
- preparation of hydraulic models for the three alignment options has commenced
- preliminary geotechnical investigation has been completed
- no unsuitable conditions were encountered.
Eastern Regulator Retrofit Program
Under the Eastern Regulator Retrofit Program, SRW plans to modernise approximately 107 regulators in Zone 5 (Eastern) of the MID. The works will be completed over the 2014 and 2015 winter maintenance periods.
The total capital cost of the proposed project is estimated at $6.05m. In return, the project is expected to produce water savings of 3,875ML as well as improved levels of customer service.
Past projects - MID 2030 Leading Works Program
The Leading Works Program was a $5m investment in the modernisation of the MID, consisting of the following projects:
- Nambrok-Denison Stage 1 and 2 Regulator Retrofit Programs
- Eastern Stage 1 and 2 Regulator Retrofit Programs
- Stage 1 and 2 of the Outlet Rationalisation Program
- Heyfield Regulator Retrofit Program
- Design and construction of the Southern-Cowwarr Balancing Storage
- Southern-Tinamba Outlet Rationalisation Investigation
- Southern-Tinamba Prototype Outlet Investigation
Stage 1 of the Nambrok-Denison, Eastern and Heyfield Regulator Retrofit Programs involved converting part of the channel system to channel automation by way of modernising the regulators and cleaning the channels in these supply zones.
The following table exhibits the outfall performance of the Heyfield supply zone after channel automation.
MID 2030 Customer Presentations – October 2011
District update – May 2013 including MID 2030 update
MID 2030 Newsletter – January 2012
MID 2030 Newsletter – October 2011
MID 2030 Newsletter – June 2011
MID 2030 Discussion Paper
MID2030 Strategy paper
MID affordability case studies
MID economic value
MID 2030 Prospectus 2014