The Irrigation Area
The Harvey Water Irrigation Area (HWIA) is located to the west of the Darling Scarp on the Swan Coastal Plain, around100 kms south of Perth. It covers an area of 112,000 hectares (around 75 kms long and 15 kms wide) in three Irrigation Zones: Harvey, Waroona and Collie. There is currently around 10,000 ha of land under permanent irrigation for dairy farming, beef grazing and horticulture, with a total irrigable area of approx 30,000 ha. The irrigable area and value of output could be further increased with the introduction of an enhanced delivery system, improved irrigation technologies and new crops with support from new investors. Total GVAP from the irrigation area is estimated at $100 million per annum.
The HWIA is different from most Australian irrigation areas because it does not have a longitudinal river system(s) from which water is diverted or pumped. Water has historically been supplied by gravity flow from dam to farm along a network of open concrete lined and earthen channels. The slopes are quite short and relatively steep and feed water laterally across the system to the irrigation farms. Water releases are actively managed using a SCADA system for automation.
Delivery Losses
Historical delivery losses have been over 30% between dam and farm and result from seepage into the ground, leaks in the channels and structures, filling of channels which have degraded to much larger than design, end of system outflows and with evaporation the smallest loss because of the short residence time the water is actually in the channels.
Asset Investment
Harvey Water understands that to retain its licensed allocation it must demonstrate that it can use water efficiently and productively for the benefit of the local and wider communities in comparison to competing uses. Since 1996 when Harvey Water took over the management and ownership of the business and its assets, $18 million of irrigators’ funds have been invested to improve the system. The major focus has always been on improving the delivery efficiency between the dams and the farms in order to reduce losses.
Harvey Pipe Project
The Harvey Pipe Project employs the very basic principle of infrastructure improvement to reduce water losses, by replacing open water delivery channels with pipelines.
The project is one component of a wider long term development project being undertaken by Harvey Water. Stage 1 of the piping project has commenced in Harvey South with all the necessary approvals and funding in place. Approvals and funding are currently being sought for piping Stage’s 2 and 3 (Uduc & Harvey North). Funding is now sought for Stage 4 of the project (Logue Brook).
The Channel Replacement Strategy is to estimated to eliminate 17.1 Gigalitres (GL) of water losses incurred during the current delivery process by installing a network of HDPE (Heavy Duty PolyEthylene) pipes in lieu of the wasteful open channel in operation. It is important to note that this is not water which is allocated to irrigators and does not reduce their water supply.
Project Goals
The goal of the project is to pipe the balance of the unpiped area in Harvey district by the end of 2009, which will result in 17.1 GL of water becoming available for trade over the period of construction.
For the irrigators, the outcome will be a pipe scheme delivering water at gravity driven static head pressure of about 70 metres. The system will be capable of supporting surface irrigation with scheduling of delivery but, importantly, will also provide the ability for farmers to readily undertake on-farm improvements in water use efficiency.
Previous Piping Projects
In 2002, Harvey Water completed over 140 km of piping in the Harvey Irrigation District to supply over 70 customers with water. In 2003, the company completed over 40 km of piping to service nearly all the 80 shareholders in the Waroona district. Both these systems provide water under head pressure from nearby dams. In Harvey a parallel system providing water through both open channel and piped systems was constructed at the request of irrigators.
There was no support available from the State government or private spheres for the piping but the Federal Department of Transport and Regional Services provided $275,000 through the Dairy Regional Assistance Program. The remainder of the $6m capital works funding came from company reserves and contributions from irrigators.
Stage 1 of the Harvey Pipe Project began in October 2005. The project is progressing well and is on schedule and on budget as at 28th April 2006. Stage 1 is forecast to be completed in June 2006. Funds for Stage 1 have been sourced from the Water Corporation on the basis of sharing the cost and sharing the water saved.
National Water Initiative (NWI)
This project is consistent with the continuing national imperative to increase the productivity and efficiency of Australia's water use, to address the need to service rural and urban communities and to improve environmental management practices Water that becomes available due to improved delivery efficiencies then becomes available for trade with the funds generated being turned back into further investments in distribution efficiency.
One of the major objectives of installing a piped irrigation water delivery system under gravity head pressure is to facilitate the improvement of on-farm water use; specifically by moving away from reliance on surface irrigation towards higher technology and more water use efficient systems such as sprinkler and trickle. This development in infrastructure will facilitate the change from low value surface irrigated pasture production for dairy and beef production to high value horticultural enterprises.
Economic Development
The strategic vision of the company is “To stimulate regional economic development through our access to irrigation water”
Pipelines do not just deliver reduced losses they stimulate the fundamental changes in on-farm irrigation which will change the way the industry produces. In previous times the system was set up to deliver large volumes of water infrequently for pasture irrigation by surface or flood methods. This was very efficient in terms of energy use since our system is totally fed by gravity.
Higher value uses of water and land such as horticulture require water in small volumes very frequently and this was hard to obtain under the old system except by building a large on-farm dam and installing a pump to deliver water as needed. The costs and inconvenience were a barrier to many irrigators.
With a pipe scheme where the water is under head pressure from the dams they now have access to water 24 hours a day 7 days a week and so have total control over the supply of water to their different crops. This system allows irrigators to easily connect much more water use efficient on-farm irrigation systems such as centre pivot and knocker sprinklers, trickle and T-tape drip systems. The resulting water savings can be used to extend the farm area irrigated each year, further increasing production and profitability.
Not only will there be a change in the type of agricultural output there will be an increase in diversity and a steady increase in area under production because of the access to water under pressure.
As well, higher value farming uses higher technology equipment and methods which, in turn, leads to an increase in the use of off-farm services and contractors.
