Depletion of Fresh Water Resources
Environmental Assessment: Pressure State Response Indicators

Industrial production systems place considerable demand on fresh water resources: Irrigation for Feed Production - in competition with other local demands for crop production and reducing downstream flows and downstream water quality; Water for Animal Production - consumption and cleaning livestock housing; and Water for Processing Animal Products - used in industrial processing animal and waste disposal. | Pressure State Response

The biggest problems with demand competition are likely to be with the Animal Production and Animal Products Processing. These activities are generally carried out near urban centres where there are existing and expanding demands for fresh water for domestic and industrial use. Demand projections show that overall shortages are likely to occur in almost all major urban centres within the next 25 years.

The impact of this demand is to reduce available supplies to other competing users, and to reduce flow and indirectly quality of water in natural environments.

Again the problem of fresh water demand and impact on the environment is incremental; water use has to be looked at within the context of demand from other agricultural and industrial enterprises and demand for domestic use. The environmental demand is of particular concern and is often overlooked in the water demand balance equation, largely because there are no clear guidelines on what is the average or minimal water requirement (in terms of both quality and quantity) to maintain a given ecosystem.

Pressure

Industrial Production Systems are direct consumers of fresh water resources, reducing total available water, and polluters of fresh water resources, reducing water quality. Both aspects reduce the potential uses of water resources, and increase the costs of accessing fresh water to other users.

One major problem with the management of fresh water resources, is that demand tends to be fairly in-elastic, while water supply can be extremely variable.

Irrigation demand will decrease in years of high local rainfall, but in general as it is established in areas with low rainfall, the impact of this variability on downstream flow is overshadowed by variability in rainfall in the upstream catchment.

In feed production, pressure is characterised by:

- The area under irrigation;
- The method of irrigation, technology used and efficiency of water use
- The potential to switch to other feed production sites during periods of low water availability.

The fresh water demand for maintaining animal production systems and processing animal products is even less seasonal, as the system is based on supplying a steady market requirement for animal products. As a result there is little potential for changing management systems to reduce demand in periods of low water availability. The impact of demand is therefore greatest during the occasional but expected periods of low water availability.

In animal production and processing systems, pressure is characterised by:

- The type of enterprise and number of enterprises;
- The scale of the enterprise - small, medium or large;
- The technology used - high, medium or low;
- The method used for waste treatment and disposal;
- The number of similar or comparable enterprises using water for consumption and waste discharge - including those from other sectors.

Projections of future pressure can be based on patterns of consumption and projected socio-economic and demographic trends, particularly towards more affluent urban patterns of settlement.

State

The impact of fresh water demand is a decrease in total water volume and a decrease in water quality of the remaining water in the system. The impact of this on the environment is a loss or change in the aquatic ecosystems, with decreasing water and increasing nutrient load leading to higher risks of eutrophication.

However, as the availability of water is often highly variable, the measurement of water flows or water quality at a single point in time is not necessarily a good indicator of state.

State indicators are characterised directly by:

- Changes in flow conditions, with particular emphasis on low flow conditions;
- Changes in water quality, again with the emphasis on low flow conditions;
- Presence or loss of indicator species - vegetation and microfauna, fisheries;
- Gross changes in ecosystem or habitat;

Given that demand will be competing with other sector uses as well as the environment, an indirect indicator of the impact on the "state" will be the impact on other sectoral demand users. Reduced supply of water to other users is an indication of the likelihood of excessively low flows and polluted flows to downstream ecosystems.

Response

In most cases there is some attempt to regulate water use, both on farm in terms of use for irrigation and in the urban and peri-urban areas for animal production and processing.

Response indicators will include:

- Number of Licenses to Extract - typically with no limit to volume for irrigation, although the technology used may be specified;
- Licenses and charges for connection to mains supplies;
- Regulation of borehole construction and licenses for operating boreholes;
- Costs of Licenses;
- Variable charging rates or rebates to encourage efficient use of water;
- Monitoring/policing mechanisms for enforcement of regulations;
- Integrated management plans for allocation of water supplies to competing sectors, including the environment.

> > [Livestock & Environment Toolbox Home]