Agriculture and water impacts in northern Victoria
The northern Victorian Murray-Darling Basin accounts for about $2.5 billion per annum in irrigated agricultural production. Production is dominated by perennial horticulture (41% by value), dairy (34%), and livestock enterprises (12%). In recent years, total irrigation water usage has ranged from 1,349 gigalitre (GL) to 1,771 GL, with groundwater usage ranging from a low of 55 GL (4% of the total) to a high of 194 GL (11%) under adverse climatic conditions.
To provide for environmental needs, draft Sustainable Diversion Limits (SDLs) have been set for both surface and groundwater resources across the MDB. Under the 2,750 GL scenario, consumptive use of surface water in Victoria is expected to fall by about 30 per cent per annum on average. Conversely, increased extractions are anticipated under the groundwater SDLs.
Currently, the SDLs for groundwater are based on broad scale, simplistic approaches which do not take into account complex stream-aquifer interactions. This project involves hydrological modelling with much improved groundwater conceptualisation to refine these SDLs across the northern Victorian Murray-Darling Basin.
This project targets the northern Victorian regions of the Murray-Darling Basin and is funded from 2011 to 2014.
- Quantify sustainable yields for surface water and groundwater using biophysical models to provide a much stronger basis for informing Victorian government policy.
- Quantify the opportunity cost to irrigators of the revised diversion limits in the northern Victorian Murray-Darling Basin.
- Develop an integrated hydrological model of the lower Campaspe catchment to examine the ecological and socio-economic impacts of SDLs at the catchment scale and to assist groundwater supply managers at a more localised level.
How will this research contribute to productivity?
Reductions in water availability have significant implications for irrigated agriculture in the northern Victorian Murray-Darling Basin. Over time, irrigators will respond by rearranging the enterprise mix to use available water where it is most profitable and feasible. The dairy and mixed grazing sectors are more likely to undergo change. By contrast, perennial horticulture is expected to be more stable as horticulturalists use water markets to secure supplies.
Information is critical in minimising adjustment costs due to planned reductions in water availability. If irrigators are to have the long-term certainty and confidence needed to make investment and adjustment decisions in the future, it is important that there is clear scientific evidence that environmental flows are sustainable. This project aims to provide a much stronger basis for informing Government, Catchment Management Authorities, water authorities and irrigators on this issue.
In-kind research partners
Project Leader contact
Senior Research Scientist – Systems Modelling