Hybrid Systems

Project: Modelling and control of irrigation channels

New PhD scholarship available in modelling and control of irrigation channels. Click here (PDF) for more details.
Visit the postgraduate projects page for list of available projects.

Brief description

Irrigation is of vital importance to many communities in Australia, and many of Australia's large export earners are dependent on the availability of water for irrigation. As water is a precious resource it is important to manage it well. Irrigation channels supply farmers with water from rivers and resorvoirs, and in Victoria alone there are several hundred kilometers of irrigation networks. The water losses in these channels are large, and it is estimated that as much as the equivalent of Melbourne's total water consumption is lost in irrigation channels in Victoria alone. In most cases the losses are due to more water than necessary being released from the rivers and resorvoirs. In this project we have developed control systems which use the gates along the channels to regulate the flows and water levels. By employing such control systems the water losses are substantially reduced.

Benefit

The environmental benefits of employing modern control systems in irrigation channels are huge. Less water can be diverted to irrigation, which frees up water to be used for other purposes, such as restoration of environmental flow in the Snowy River, and reducing the environmental stresses under which the Murray Darling system is currently suffering. Using less water for irrigation will also reduce salinity problems, which is of major concern in many places in Australia.

Detailed description

The overall goal of the project is to improve the efficiency of irrigation channels. A large amount of water is "lost" in irrigation channels. It is roughly estimated that the equivalent of Melbourne's total domestic and industrial water consumption is wasted in irrigation channels in Victoria every year. Water is regarded as lost when it reaches the end of the irrigation channels without being used, since there are few opportunities to recapture water. At the end of an irrigation channel the water often just flows into the sewage system or back into a river which by this stage has become so salty that the water can no longer be used for irrigation purposes. One reason why the losses are large is that the irrigation channels are operated on the conservative side, with large amounts of water let through in order to nearly always be able to guarantee the supply of water to farmers when they need it. Hence there is a conflict between minimising water losses in irrigation channels and reliability of the water supply.

This project has been focusing on minimising the water losses through better control and regulation of the water levels and flows in irrigation channels. The water levels and flows are controlled by operating gates which are located along the channel. At each gate we have measurement of water levels upstream and downstream and gate positions. These measurements are transmitted back to a central computer via a radio network. At each gate there are motors which can lower and raise the gates. The idea is that by better automatic regulation of the water levels we can substantially reduce the losses. The reason being that the automatic control system will make sure that the water levels do not go below the critical levels necessary to ensure reliable supply of water, and at the same time it will do so in such a way that the amount of water that reaches the end of the channel is kept to a minimum. This project has been dealing with deriving mathematical models of the irrigation channels from observed data (water level and gate position measurement), and then using these models to design and implement automatic control systems for regulation of water levels. The control system uses the measured water levels and demand information to calculate the new gate positions.

The kind of problems considered in this project are becoming increasingly important. The restoration of environmental flow in the Snowy River and the increasing concerns about the Murray River have highlighted the need to save water. A common suggestion has been that less water should be diverted for irrigation. A result of this project is that, less water can indeed be diverted, without affecting the supply to farmers. The environmental benefits are therefore potentially very large.

For more information contact: Eric Weyer or Iven Mareels