How could managed aquifer recharge be feasible in the Coleambally Irrigation Area?

Figures & data

Figure 1. The argumentation approach developed for this study, with associated guiding questions and how this approach was applied in Coleambally Irrigation Area of Operations (CIA). CICL = Coleambally Irrigation Co-operative Limited, CRDC = Cotton Research & Development Corporation, MAR = managed aquifer recharge.

Figure 2. The Coleambally Irrigation Area and surrounds.

Table 1. The seven feasibility criteria and respective key considerations/questions, and the methods used to inform the analysis adapted from Ticehurst and Curtis (2017). MDB = Murray Darling Basin, MAR = Managed aquifer recharge.

Criteria	Example questions and considerations	Methods used to assess
Effective demand for products	Is there demand for more water or greater water security? Who wants the water and when?	Gauged the local demand for change to existing water management, using stakeholder workshops and phone interviews.
Water availability	Is water available to be banked underground (e.g. unused surface water shares, surface water traded in when prices are low)?	Reviewed water allocation, use, carryover, and entitlement data to identify potential sources of water to be banked via MAR
Technical feasibility	Is there space in the aquifer systems to store surface water for drier times? How can the water be recharged, stored and extracted?	Considered aquifer and soil characteristics, a MAR suitability assessment previously undertaken in the area, literature review of MAR methods, and how a monitoring program could be implemented
Financial viability	Can MAR be a viable and profitable alternative to surface storage schemes? What are the critical factors affecting financial viability?	Assessed the levelized cost of MAR using differing water sources, compared to surface storage cost
Environmental risks	Are there any significant effects on water quality and quantity (positive or negative)? What are the consequential impacts of any change on farmland and ecosystems?	Investigated effect of banking ‘unused’ water on downstream environments, water quality risks and potential benefits to aquifer health associated with MAR
Social acceptability	Is it a socially acceptable option to irrigators and other stakeholders? What are people’s values, knowledge and beliefs about MAR? Do they perceive risks about its implementation in their region?	Elicited opinions on MAR during stakeholder workshops and phone interviews
Governance arrangement	Are the legislative and policy settings appropriate to support a MAR system? If not, how would they need to be changed?	Reviewed legislation and policy related to MAR at the federal, state and MDB level

Figure 3. Potential of MAR building on scenarios within an argumentation approach. Managed aquifer recharge (MAR) scenarios (blue boxes) and alternate scenarios (grey boxes) with arguments for MAR in green. Section numbers are shown in square brackets.

Table 2. Assessment of feasibility criteria for Managed aquifer recharge (MAR) scenario (Don’t miss a drop) and alternate surface storage scenario (Surface storage) that both store ‘unused’ allocations (e.g. supplementary entitlements). More details are provided in the project report (Guillaume et al. 2020).

Scenario	Don’t miss a drop	Multi-year water storage
Effective demand for products	Variable and low allocations mean that water is valuable and fully using entitlements is worthwhile
Water availability	During long events with wet antecedent conditions, supplementary allocations that would otherwise be forgone by members could be banked Water entitlements that cannot be carried over could also be banked
Technical feasibility	High flows capture is limited by main channel intake and recharge rate across multiple infiltration and injection sites	Large dams, likely with high evaporation, would be needed to allow for interannual storage
Financial viability	Levelised cost of MAR water is competitive with market value of water in dry years	Large corporations in the region have found the building of dams viable, with government subsidies
Environmental risk	Capture of full supplementary water allocations may affect environmental flows, and be further regulated
Social acceptability	Multi-stage pilot projects may resolve community concerns and minimise initial investment risk	There has been public opposition to other large dams built in the region
Governance arrangements	Injection is subject to NSW Aquifer Intervention Policy; any project will require project assessment process or new water recovery rules	Other large dams have been successfully completed and audited

Table 3. Managed aquifer recharge (MAR) scenario (MAR community sustainability) and alternate surface storage scenarios that store current entitlements or require policy change. More details are provided in the project report (Guillaume et al. 2020).

Scenario	MAR for community sustainability	Community sustainability through high security entitlements	Community sustainability through policy change
Effective demand for products	While cotton is an opportunistic crop, evening out peaks and troughs could allow greater investment in supply chains, infrastructure, justify cost of pickers, and take-up of forward contracts, allowing farmers to farm and the community to endure extended dry periods
Water availability	Long term storage of part of conveyance and general security allocations (487 GL held in 2019)	Current high security surface water entitlements for Coleambally are ~8.4 GL. Somehow more would need to be acquired	Requires a serious change in how water is allocated during times of drought, (e.g. allowing environmental water allocations to be sold on market)
Technical feasibility	Preliminary analysis suggests it is possible. Further testing would identify best locations and mechanisms for long term recharge	Existing reservoirs would be used, changes are required only in allocation and governance
Financial viability	Benefits for viability of co-operative and sustainability of community can warrant additional co-investment	Expense of high security water entitlements would require support for market purchases or reallocation	The freed (environmental) water would be available on the water market, and likely to attract high prices similar to high security entitlements
Environmental risk	Artificial recharge comes with potential risks for water quality and minimum impact considerations must be met to proceed	Negligible – little change from current reservoir operations, greater water in dry years in the irrigation district	Environmental risk would be managed by the Commonwealth Environmental Water Holder to meet dry and wet year objectives, and they would decide when to release water
Social acceptability	Change process could be shepherded by a trusted organisation in the community with a history of innovation and experience in managing water and change (e.g. CICL), providing example of best practice in management of district-scale water resources	Not all communities could use this strategy. High security would need to be seen as community entitlements rather than high value entitlements, otherwise there would be pressure to sell water	Not all communities could use this strategy. Freed (environmental) water would need to be seen as community entitlements. This is likely to be contentious within and outside the Murrumbidgee
Governancearrangements	Large scale community projects can be developed collaboratively with local, state and/or national government with project-specific assessment processes	Possible within current water market mechanisms	Current water sharing arrangement would need to be revised, for example, to allow for the sale of environmental water when deemed necessary and when critical environmental needs are met

Table 4. Managed aquifer recharge (MAR) scenario that stores water to facilitate conjunctive water use. More details are provided in the project report (Guillaume et al. 2020).

Scenario	Integrated groundwater and surface water delivery
Effective demand for products	Irrigators already use both groundwater and surface water entitlements. Increased groundwater use in drought is limited by long term SDL and MAR could alleviate this constraint
Water availability	Managing surface and groundwater conjunctively means that the focus is on balancing reservoir and aquifer levels. Only using groundwater in dry years may free up conveyance water by reducing the use of canals
Technical feasibility	A focus on condition-based management (e.g. target levels of local drawdown) rather than extraction volumes (i.e. SDL) reduces barriers to operation
Financial viability	As part of broader strategies for managing drawdown, investment would be divided between MAR and delivery infrastructure, as well as improved groundwater monitoring
Environmental risk	Explicit management of groundwater levels benefits from understanding of effects of drawdown on dependent ecosystems
Social acceptability	Long term transition would involve greater understanding of current groundwater use and availability, integration into surface water delivery operations, and coordination of water sources before integrating MAR
Governance arrangements	Possible now with approval through NSW Aquifer Intervention Policy, but decisions on groundwater use restrictions would need to account for drawdown to guarantee access in drought periods as well as clarifying rights to surface water post infiltration

Figure 4. Recommendations for initial steps towards implementation of manage aquifer recharge (MAR) in Coleambally Irrigation Area of Operations. Recommendations are provided for the Coleambally Irrigation Co-operative Limited (CICL) and Cotton Research & Development Corporation (CRDC). MDBA = Murray Darling Basin Authority, R&D = research and development. Although the recommendations here are aimed at the two case study agents of change (CICL and CRDC), they could be applicable to other MAR innovators, both in a local or supporting role.

Table

	Number of participants
Stakeholder group representatives	Interviews	Workshops	Total^a
Irrigators	4	4	8
Industry representatives	5	3	7 (1)
Environmental managers	1	1	2
Water managers	2	7	8 (1)
Other^b	2	3	4 (1)
TOTAL no. people	14	15 (3)^c	29 people involved in project discussions

^aThe numbers in brackets are the number of people who had been interviewed and also had been invited to workshops. ^b ‘Other’ include researchers, water brokers, a representative from the NSW irrigators council and a cotton gin operator. ^c Some people invited to workshops were representing more than one stakeholder group (e.g. they were an irrigator who also sat on the NSW irrigators council).

Ticehurst, J., and A. Curtis. 2017. Preliminary Assessment of Conjunctive Use Opportunities in the Murray-Darling Basin: A Case Study in the Lower Campaspe Catchment. Wagga Wagga, NSW: Murray-Darling Basin Authority, National Centre for Groundwater Research and Training.

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Guillaume, J. H. A., N. Harvey, W. S. Merritt, and J. L. Ticehurst 2020. Feasibility Study of Managed Aquifer Recharge for Improved Water Productivity for Australian Cotton Production. http://www.insidecotton.com/xmlui/handle/1/4874.

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