Using proportional modeling to evaluate irrigator preferences for market‐based water reallocation

Irrigators’ policy preferences for water reallocation programs usually take the form of proportional data, where one option will be relatively more or less favored than another in the composition of a government's total budget apportionment to address water reform. This study applies a zero‐one inflated beta regression to model Murray–Darling Basin irrigators’ preferences for market‐based water policy programs. Market‐based arrangements are more likely to provide efficient solutions to water reallocation problems, particularly where future uncertainty and appropriate pricing induce irrigator preferences for such programs. Our modeling of drivers of irrigator preferences for government expenditure on market‐based programs identified different determinants of zero (a corner solution) and proportional outcomes for the reallocation of Murray–Darling Basin water. In addition, the proportional modeling identifies some variables (namely, state regional influences, the type of farm production and recent debt, low income, or water allocation stressors) that increase engagement with market‐based programs. Interestingly, while price variables are important and statistically significant, they appear to be less relevant to program engagement than other influences.     

Allocation trade in Australia: a qualitative understanding of irrigator motives and behaviour*

Governments in Australia are purchasing water entitlements to secure water for environmental benefit, but entitlements generate an allocation profile that does not correspond fully to environmental flow requirements. Therefore, how environmental managers will operate to deliver small and medium‐sized inundation environmental flows remains uncertain. To assist environmental managers with the supply of inundation flows at variable times, it has been suggested that allocation trade be incorporated into efforts aimed at securing water. This paper provides some qualitative and quantitative perspective on what influences southern Murray–Darling Basin irrigators to trade allocation water at specific times across and within seasons using a market transaction framework. The results suggest that while irrigators now have access to greater risk‐management options, environmental managers should consider the possible impact of institutional change before intervening in traditional market activity. The findings may help improve the design of intervention strategies to minimise possible market intervention impacts and strategic behaviour.     

Upstream demand for water use by new tree plantations imposes externalities on downstream irrigated agriculture and wetlands*

Large‐scale tree plantations in high rainfall upstream areas can reduce fresh water inflows to river systems, thereby imposing external costs on downstream irrigation, stock and domestic water users and wetland interests. We take the novel approach of expressing all benefits and costs of establishing plantations in terms of $ per gigalitre (GL) of water removed annually from river flows, setting upstream demands on the same basis as downstream demands. For the Macquarie Valley, a New South Wales sub‐catchment of Australia’s Murray‐Darling Basin, we project changes in land and water use and changes in economic surpluses under two policy settings: without and with a policy requiring permanent water entitlements to be purchased from downstream parties, before plantation establishment. Without the policy, and given a high stumpage value for trees ($70/m³), upstream gains in economic surplus projected from expanding plantations are $639 million; balanced against $233 million in economic losses by downstream irrigators and stock and domestic water users for a net gain of $406 million, but 345 GL lower mean annual environmental flows. With the policy, smaller gains in upstream economic surplus from trees ($192 million), added to net downstream gains ($138 million) from sale of water, result in gains of $330 million with no reduction in environmental flows. Sustaining the 345 GL flow for a $76 million (406–330) reduction in gains to economic surplus may be seen to cost only $0.22 million/GL; but this is much lower than the market value of the first units of that water to agriculture and forestry.     

Declining inflows and more frequent droughts in the Murray–Darling Basin: climate change,impacts and adaptation*

It is likely that climate change will be associated with reductions in inflows of water to the Murray–Darling Basin. In this study, we analyse the effects of climate change in the Murray–Darling Basin using a simulation model that incorporates a state‐contingent representation of uncertainty. The severity of the impact depends, in large measure, on the extent to which climate change is manifested as an increase in the frequency of drought conditions. Adaptation will partially offset the adverse impact of climate change.     

Economic effects of water recovery on irrigated agriculture in the Murray‐Darling Basin*

In October 2010, the Murray‐Darling Basin Authority (MDBA) proposed that a range of 3000–4000 GL per year, on average, of additional water be made available for the environment in the Murray‐Darling Basin (MDB) to mitigate the effects of what it considers to be inadequate environmental flows. To help quantify the costs of this water reallocation, a hydro‐economic model was constructed based on the 19 regions of the MDB. The model results indicate the following: (i) substantial reductions in surface water extractions of up to 4400 GL per year impose only a moderate reduction on net profits in irrigated agriculture, Basin wide, given competitive water markets, but the effects are much more pronounced in particular regions/catchments and (ii) the costs of the water reallocation are comparable with the amount budgeted by the Australian government to acquire water from willing sellers and increase environmental flows if inter‐regional water trade is unrestricted.     

The impact of drought and water scarcity on irrigator farm exit intentions in the Murray–Darling Basin

Drought and future water scarcity in the Murray–Darling Basin (MDB) will continue to restructure the irrigation industry in the coming decades. There has been little work conducted in Australia that has modelled farm exit or exit intention. ABARES farm survey data were used to model irrigators’ farm exit intentions across the southern MDB from 2006 to 2013. In particular, we examined the hypotheses that drought and water scarcity positively impacted on farm exit intentions and that it is the poorest performing farms that intend to exit in times of drought. Results revealed that water scarcity impacts varied considerably. There was only weak evidence to suggest that irrigators’ exit intentions were higher in times of drought, but there was stronger evidence to support the influence of a lagged water scarcity impact on farm exit intentions during periods of nondrought (e.g. intending to exit at times when the property market was less depressed). There was also strong evidence that poorer performing farms (measured by rates of return and higher debt over a certain level) were more likely to have exit intentions in drought periods, but not necessarily so in nondrought periods. Older age is the most consistent predictor of farm exit intentions across all industries, though it was most significant in drought periods.     

Water use and salinity in the Murray–Darling Basin: A state-contingent model*

The supply of water for irrigation is subject to climatic and policy uncertainty. The object of the present paper is to show how the linear and non-linear programming models commonly used in modelling problems such as those arising in the Murray–Darling Basin may be adapted to incorporate a state-contingent representation of uncertainty. Estimates showing the potential value of improved water use are also derived.     

Policy review of water reform in the Murray–Darling Basin,Australia: the “do's” and “do'nots”

The water reforms undertaken in the Murray–Darling Basin, Australia since 2007 have been viewed as a model for other countries seeking to respond to water insecurity. Here, a policy review is provided of this water reform and whether it delivers on key environmental objectives in the 2007 Water Act (the Act). The evaluation includes a review of the 2012 Basin Plan, a key instrument of the Act, and complementary policies associated with the acquisition of water entitlements for the environment via direct (reverse tenders) and indirect (infrastructure subsidies) means. Using the objects of the Act as a benchmark, an evaluation is provided of the following: (i) planned reductions in irrigation water extractions in the 2012 Basin Plan; (ii) risks associated with the 2018 amendments to the Basin Plan that, collectively, allow for an increase in irrigation water extractions of some 22 per cent, relative to the sustainable diversion limits specified in the 2012 Basin Plan; (iii) Basin‐scale environmental outcomes achieved, as of the end of 2018; and (iv) economic effects of direct and indirect methods of acquiring water for the environment. Findings from the review generate the “Do's” and “Do Nots” of water reform for Australia, and possibly other countries, when managing the trade‐offs between water for irrigation and the environment.     

Achieving environmental flows where buyback is constrained

Theory suggests that the development of common property increases national welfare, and consistent with this thinking Australia's Murray–Darling Basin (MDB) Plan uses a common property approach to recover environmental water rights in the national interest. Two water recovery instruments are used: purchasing water rights (buyback) from farmers, and saving water by subsidising irrigator adoption of technically efficient technology. A moratorium on buyback has focused environmental recovery on subsidised technically efficient technology adoption. Economists argue that national welfare is maximised via buyback and highlight the limitations of efficiency savings to recover sufficient environmental water. A risk is that water recovery targets may be reduced in future, limiting welfare gains from water reform. This article evaluates possible welfare trade‐offs surrounding environmental water recovery outcomes where arbitrary limits on buyback are imposed. Results suggest that, on average, strategies which attempt to obtain >1500 gigalitres (GL) of water from on‐farm efficiency investments will only provide sufficient resources to meet environmental objectives in very wet states of nature. We conclude that reliance on technically efficient irrigation infrastructure is less economically efficient relative to water buyback. Importantly, the transformation of MDB irrigation will significantly constrain irrigators' future capacity to adapt to climate change.     

A MIXED INTEGER LINEAR PROGRAMMING EVALUATION OF SALINITY AND WATERLOGGING CONTROL OPTIONS IN THE MURRAY-DARLING BASIN OF AUSTRALIA

Pollution of the River Murray by salt imposes costs on domestic and industrial users in Adelaide and to irrigators on the River Murray. Salt enters the Murray-Darling system through saline ground water aquifers and from irrigation and drainage of saline land. Irrigation and drainage generate benefits from improved agricultural productivity and impose costs through increased salt loads to the Murray-Darling system. The salinity of the River Murray can be reduced by pumping highly saline ground water into evaporation basins before it enters the River Murray. This paper presents a mixed integer linear programming model which is used to determine the mix of ground water interception schemes and land improvement schemes that minimises the net present value (over a time horizon of 30 years) of total Murray-Darling Basin costs due to salinity and waterlogging. By varying a target salinity level, the mix of works that yields various salinity targets in the River Murray at minimum cost is obtained. The sensitivity of the optimal solution to prescribed changes in costs and benefits of projects and to a longer planning horizon is examined.     

Presumptions of linearity and faith in the power of centralised decision‐making: two challenges to the efficient management of environmental water in Australia

Water policy in the Murray‐Darling Basin continues to be dominated by the trade‐offs between agricultural and environmental interests. This has recently been played out with the acrimonious debate that circumscribed the release of the Guide to the Murray‐Darling Basin Plan. In this paper, we argue that too much emphasis has been placed on the volume of held water as an indicator of environmental benefit. We also contend that there is an attendant presumption of linearity in the relationship between volumes of held water and environmental benefit which could lead to perverse outcomes. A second problem is that there is too much enthusiasm for contemplating the solutions to water management problems as residing primarily at the federal level of government. These factors stand to ultimately limit the efficient delivery of environmental objectives.     

Marginal abatement costs of greenhouse gas emissions: broadacre farming in the Great Southern Region of Western Australia

Broadacre agriculture is a major emitter of greenhouse gases (GHG). To improve efficiency of climate change policies, we need to know the marginal abatement costs of agricultural GHG. This article combines calculations of on‐farm GHG emissions with an input‐based distance function approach to estimate the marginal abatement costs for a broadacre farming system in the Great Southern Region of Western Australia. The results show that, in the study region, the average marginal abatement cost for the 1998–2005 periods was $29.3 per tonne CO₂‐e. Farms with higher crop output shares were found to have higher marginal abatement costs. Overall, our results indicate that broadacre agriculture is among the lowest cost sources of GHG mitigation.     

Effective use of public funding in the Murray‐Darling Basin: a comparison of buybacks and infrastructure upgrades

Policy instruments designed to increase environmental flows in the Murray–Darling Basin are compared using TERM‐H₂O, a detailed, dynamic regional CGE model. Voluntary and fully compensated buybacks are much less costly than infrastructure upgrades as a means of obtaining a target volume of environmental water, even during drought, when highly secure water created by infrastructure upgrades is more valuable. As an instrument of regional economic management, infrastructure upgrades are inferior to public spending on health, education and other services in the Basin. For each job created from upgrades, the money spent on services could create between three and four jobs in the Basin.     

Modelling drought and recovery in the southern Murray‐Darling basin*

The prolonged drought from 2006–07 to 2008–09 in south‐eastern Australia presented severe difficulties for dry‐land and irrigation farmers in the southern Murray‐Darling basin. A dynamic multi‐regional computable general equilibrium model (TERM‐H2O) is used to estimate the economy‐wide small region impacts during and after drought. Drought reduces real GDP in some small regions by up to 20 per cent. Irrigation water trading and farm factor movements alleviate losses. The drought results in an estimated 6000 jobs being lost across the southern basin. Depressed farm investment during drought results in farm capital not returning to baseline levels after drought. Consequently, job numbers in 2017–18 remain 1500 below forecast in the southern basin.     

Do Differences in the Scale of Irrigation Projects Generate Different Impacts on Poverty and Production?

This article investigates differences in household production and consumption among small‐ and large‐scale irrigators to assess whether the scale of an irrigation project increases household welfare in Mali. Much of the evidence of the impact of irrigation does not use counterfactual analysis to estimate such impact or distinguish between the scale of the irrigation projects to be evaluated. In the dataset collected by the author, both a large‐scale irrigation project and small‐scale projects are used to construct counterfactual groups. Propensity score matching is used to estimate the average treatment effect on the treated for small and large irrigators relative to non‐irrigators on agricultural production, agricultural income and consumption per capita. Small‐scale irrigation has a larger effect on agricultural production and agricultural income than large‐scale irrigation, but large‐scale irrigation has a larger effect on consumption per capita. This suggests that market integration and non‐farm externalities are important in realising gains in agricultural surplus from irrigation.     

Irrigator preferences for water recovery budget expenditure in the Murray-Darling Basin,Australia

This study presents results from a survey of southern Murray-Darling Basin irrigators about the percentage of funds they would allocate towards a variety of current and hypothetical trade-off choices for recovering environmental water. The findings, allowing for state-based differentials, suggest irrigators marginally prefer infrastructure expenditure above the sum of a set of market-based options (namely water entitlement purchasing, temporary water market products and exit-based packages). However, their infrastructure preference weighting is less than current budget expenditure, and use of market-based options has higher support from irrigators than current policy recognises. Further, analysis of past and current infrastructure and market-based water recovery expenditures reveals large price-per-megalitre disparities, which may be explained by diminishing marginal returns. Targeting expenditure in line with preferences of irrigators may result in increases in economic efficiency.     

Impacts of climate change on lower Murray irrigation*

This article evaluates irrigated agriculture sector response and resultant economic impacts of climate change for a part of the Murray Darling Basin in Australia. A water balance model is used to predict reduced basin inflows for mild, moderate and severe climate change scenarios involving 1, 2 and 4°C warming, and predict 13, 38 and 63% reduced inflows. Impact on irrigated agricultural production and profitability are estimated with a mathematical programming model using a two‐stage approach that simultaneously estimates short and long‐run adjustments. The model accounts for a range of adaptive responses including: deficit irrigation, temporarily following of some areas, permanently reducing the irrigated area and changing the mix of crops. The results suggest that relatively low cost adaptation strategies are available for a moderate reduction in water availability and thus costs of such a reduction are likely to be relatively small. In more severe climate change scenarios greater costs are estimated. Adaptations predicted include a reduction in total area irrigated and investments in efficient irrigation. A shift away from perennial to annual crops is also predicted as the latter can be managed more profitably when water allocations in some years are very low.     

Risk management strategies using seasonal climate forecasting in irrigated cotton production: a tale of stochastic dominance

Decision-making in agriculture is carried out in an uncertain environment with farmers often seeking information to reduce risk. As a result of the extreme variability of rainfall and stream-flows in north-eastern Australia, water supplies for irrigated agriculture are a limiting factor and a source of risk. The present study examined the use of seasonal climate forecasting (SCF) when calculating planting areas for irrigated cotton in the northern Murray Darling Basin. Results show that minimising risk by adjusting plant areas in response to SCF can lead to significant gains in gross margin returns. However, how farmers respond to SCF is dependent on several other factors including irrigators' attitude towards risk.     

State‐contingent analysis of farmers’ response to weather variability: irrigated dairy farming in the Murray Valley,Australia

The agricultural sector is commonly regarded as one of the most vulnerable to climate change. Current understanding of the impact of climate change on this sector relies on the underlying assumptions about farmers’ possible responses to weather variability, including changes in crop choice, input combinations and land management practices. Many previous analyses rely on the implicit (and restrictive) assumption that farmers operate under a fixed technology set across different states of nature. This assumption, represented through stochastic production or profit functions, is commonly made but seldom tested and may understate farmers’ responses to climate change if state‐contingent production technologies are, in reality, more flexible. The potential for farmers to adapt production technologies in response to unforeseen events is at the core of the state‐contingent approach. Advanced in Chambers and Quiggin (2000), the theory contends that producers can manage uncertainty through the allocation of productive inputs to different states of nature. In this article, we test the assumption that farmers’ observed behaviour is consistent with the state‐contingent production theory using farm‐level data from Australia. More precisely, we estimate the milk production technology for a sample of irrigated dairy farms from the southern Murray–Darling Basin over the period from 2006–2007 to 2009–2010.     

Is there evidence of insider trading in Australian water markets?

Insider trading is a much studied form of market manipulation in the financial market literature. However, studies addressing the issue of insider trading in resource markets, and in particular water markets, are rare. This study investigates the occurrence of insider trading practices around important water market allocation announcements in the Goulburn temporary water market trading zone in the Murray–Darling Basin, Australia, which is one of the largest and longest operating water market districts in the world. Nine years of daily water allocation volume and price transactions between 2008 and 2017 are modelled, with some evidence found of abnormal price movements in the 3 or 5 days preceding water allocation announcements, and especially before the introduction of insider trading rules in 2014. However, although the results do suggest some very weak statistically significant evidence that insider trading may still be present in Goulburn water markets post‐2014, it is just as feasible that our results may also reflect an increased sophistication of trader behaviour over time.