Evaluating improvements in irrigation efficiency as a salinity mitigation option in the South Australian Riverland

Abstract

A modelling framework incorporating relationships between agricultural production and groundwater hydrology was developed to estimate the bene¢ts of improved irrigation e¤ciency in the Riverland of South Australia. Increased irrigation e¤ciency can generate external bene¢ts to downstream users through reduced discharge of saline groundwater. In the Riverland these bene¢ts are large in comparison to the direct value of the irrigation water. However, the nonexclusive and site-speci¢c nature of these bene¢ts makes it di¤cult to fully internalise them through market instruments such as salinity credits. Achieving optimal irrigation e¤ciency is likely to require institutional arrangements that promote collective investment and public expenditure.

Mathematical optimisation of drainage and economic land use for target water and salt yields*

“…For example (i) targeted reforestation is likely to be a more cost-effective strategy to manage salinity than broad-scale landuse change; (ii) the hydrological characteristics of a region affect the costs and benefits of salinity management strategies; (iii) reforestation targeted to landscapes with faster responding aquifers and porous soils are more likely to generate net salinity benefits; (iv) the distribution of favourable hydrological characteristics in the landscape will determine whether revegetation is a cost-effective salinity management tool; and (v) increased irrigation efficiency can generate external benefits to downstream users through reduced discharge of saline groundwater (Heaney et al . 2000(Heaney et al . , 2001b.…”

Australasian environmental economics: contributions, conflicts and ‘cop‐outs’*

“…The flexibility of the bioeconomic modelling has been demonstrated by research conducted by Heaney et al (2001) on water salinity, Cacho et al (2001) on dryland salinity control and Cacho et al (2003) on carbon sequestration opportunities. Cassells and Meister (2001) demonstrated the potential for using Computable General Equilibrium modelling in costing the New Zealand dairy industry's response to national water quality standards.…”

Basin efficiency approach and its effect on streamflow quality, Zerafshan River Uzbekistan

“…Most of these studies focus on urban, industrial and agricultural pollution, but not necessarily on increases of salinity based on return flow from agriculture. Basins in which the effects of basin efficiency and saline return flows on downstream users have been studied and therefore policy recommendations have been formulated and implemented are the Colorado (Gardener and Young, 1990), the Murray-Darling (Heaney et al, 2001) and the Ebro (Causapé et al, 2006), hence mainly in the developed world. Gardener and Young (1990) report on the solutions found in the Colorado river, these include salinity reducing measures like desalinisation plants at different locations at the river and some voluntarily on-farm measures as well as taking areas out of agricultural production (Colorado River Basin Salinity Control Forum, 2011).…”