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Chapter 7

Drought, climate change and critical human water needs

Australia is the driest populated continent in the world. It has a highly variable climate, with a history of recurrent droughts and large floods.1
The hydrological conditions for the Murray-Darling Basin can differ year to year and across regions. Planning for wet and dry conditions is a major challenge for river operators, water resource managers and the community.2
Changes in global and regional climate patterns provide further challenges in the Basin. The Murray–Darling Basin Authority (MDBA) works with other Australian Government agencies, including the Australian Bureau of Meteorology (BoM), the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and Basin state governments to understand climate risk and manage the Basin’s water resources under these changing conditions.3
A sharp decline in the conditions of the Basin's environment during the Millennium Drought prompted the development of the Basin Plan. As noted earlier in this report, the Basin Plan is not intended to drought-proof the Basin. Nonetheless, the Water Act 2007 (Cth) (Water Act), the Basin Plan and the National Water Initiative (NWI) set forward requirements for the MDBA and Basin states to plan for dealing with drought and climate change and ensuring water is available for critical human needs.

Many locations in the Basin are experiencing severe drought conditions

Farmers and communities across many locations in the Murray-Darling Basin are currently experiencing severe drought conditions. The drought conditions are having a range of impacts on the environment and communities. Some Basin towns are on water restrictions, and many farmers face the likelihood of very low to zero water allocations.4
As at 18 September 2019, Northern Basin water storages were at 9 per cent and Southern Basin water storages were at 47 per cent.5
In its August 2019 meeting, the Murray-Darling Ministerial Council discussed the possibility that dry conditions would continue into the 2020-2021 water year, potentially triggering tier 2 water sharing arrangements in the southern Basin. Tier 2 water sharing arrangements result from very low water availability and mean that critical human water needs are prioritised over all other water entitlements. 6
During drought, all water entitlement holders are treated equally, and all allocations are reduced, regardless of whether the water is for farming or the environment. In a dry year less water is allocated and available for use, and in a wet year there is more water available for use. The allocation system adjusts year-to-year depending on climate variations.7

Figure 7.1:  Water allocations and usage in different climatic conditions

Source: Murray-Darling Basin Authority, Climate change and the Murray-Darling Basin Plan, MDBA Discussion Paper, February 2019, (accessed 3 October 2019).

Water for Critical Human Needs is prioritised in the Basin Plan

Critical human water needs (CHWN) are the minimum volumes of water that can reasonably be provided from Basin resources to meet core human consumption requirements that, if not met, would cause prohibitively high social, economic or national security costs. The Basin provides water to over three million people for CHWN such as drinking, food preparation and sanitation.
Under the Basin Plan, CHWN are managed through two planning mechanisms:
For communities that are dependent on the River Murray system, the Basin Plan (Chapter 11) and the Murray-Darling Basin Agreement set specific water volumes required to meet CHWN, and establish a tiered approach to water sharing. These provisions were forged during the Millennium Drought and reflect the lessons of that extreme dry period.
For other Basin communities (those that are not dependent on water from the River Murray System), the Basin Plan (Chapter 10, Part 13) requires that Water Resource Plans (WRPs) describe how CHWN will be met (for each WRP Area) during extreme events.8

The Water Act and the Basin Plan include requirements to ensure water is available for critical human needs

The Water Act outlines how the Basin Plan will ensure water is made available for CHWN. The Basin Plan must:
be prepared with regards to the agreement that critical human water needs are the highest priority water use for communities who are dependent on the Basin water resources;
acknowledge that conveyance water, which enables the delivery of CHWN, will receive first priority from the water available in the system;
include a statement from each Basin state that is a referring state (other than Queensland) about how much water is required to meet their CHWN and how much conveyance water is needed to deliver this water.
specify water quality trigger points and salinity trigger points at which water in the River Murray System becomes unsuitable for meeting CHWN.9
In the River Murray system, a tiered approach to water sharing is used to meet CHWN. Tier 1 represents normal water availability, Tier 2 is very low water availability and Tier 3 is extremely low water availability. Tier 2 and 3 water sharing arrangements occur in extreme conditions, similar to, or worse than the Millennium Drought. The trigger points for moving between tiers are set out in the Basin Plan. Each tier has defined provisions for water sharing to ensure critical human water needs can be met.

Figure 7.2:  Tiered water sharing arrangements in the River Murray System

Source: Murray-Darling Basin Authority, Critical human water needs, (accessed 10 October 2019).

Water Resource Plans detail processes for dealing with extreme events

The CHWN provisions under Chapter 11 of the Basin Plan do not apply to all Murray-Darling Basin communities. In Basin communities that are not dependent on water from the River Murray system, the Basin Plan (Chapter 10, Part 13) requires that WRPs describe how CHWN will be met (for each WRP Area) during extreme events. Extreme events include extremely dry periods, water quality events and infrastructure failure that could impact the supply of water for CHWN.10
Extreme event provisions include:
roles and responsibilities relating to the management of water resources during extreme events;
the water management actions that will be implemented to respond to extreme events (for example restrictions on water take, the policies for determining the level and timing of those restrictions, and how water will be provided to the point of use);
a demonstration of how the WRP will perform under extreme circumstances;
alternative water management rules to manage water resources during extreme events (for example, changes in the way that water allocation rules are applied);
estimates of the volume of water required to meet CHWN;
the indicators that will be used to assess whether an event (such as a dry period or water quality event) is classified as extreme and determine the type or level of action to be taken (for example, specifying the duration or severity of an extreme event); and
circumstances in which a WRP can be suspended and the extent of temporary rules that could be put in place.11

Role of water infrastructure development

Noting that the development of water infrastructure, including water storages, is a policy issue that impacts all of Australia, not just the Murray-Darling Basin region, there has been recent debate about the development of dams amid concerns for water security during drought and the pressure of a growing population.12
The Productivity Commission's 2017 inquiry into the reform of Australia's water resources sector noted that there has been less focus on urban water reform in recent years.
The Productivity Commission recommended that, given the challenges of population growth and the impact of climate change there is a need to ramp up reform in urban water management to ensure the demands of Australia’s growing cities can be met efficiently and that water services remain affordable over the long term.13
On September 2019, Minister Littleproud, said that states have failed to match water storage with population growth over the past two decades, and that despite considerable funding through the National Water Initiative Development Fund, they have had to 'drag most states kicking and screaming to build new dams'.14
On 14 September 2019, the Hon Michael McCormack MP, Deputy Prime Minister and Minister for Infrastructure, Transport and Regional Development, launched the National Water Grid Authority. The new authority will play a key role in shaping national water infrastructure policy, and identify opportunities to build water infrastructure to secure long-term water supplies across the country. The Deputy Prime Minister explained that the National Water Grid would 'take out the state-based politics and insert the science with a national-based approach to water security for Australia's future'.15

How is research and data used to plan for the impacts of drought and climate change in the Basin?

The Water Act requires the Basin Plan to be based on the basis of the best available scientific knowledge, and to identify risks to the availability of Basin water resources due to the effects of climate change.
The MDBA has developed research partnerships with a range of institutions, including the University of Canberra, the Murray-Darling Freshwater Research Centre and CSIRO, to:
provide advice on research gaps and scoping of research projects;
synthesise existing scientific knowledge;
undertake commissioned research and analysis to meet specific needs;
provide advice on the best available science and evidence base including knowledge gaps; and
provide peer review to ensure best available science is being used and the evidence base in continually improved. 16
Under the Water Act, the Bureau of Meteorology (BoM) has responsibilities to compile and deliver information about water resources across Australia. It further has responsibility for compiling and managing water accounts, including the National Water Account. The Water Act requires all states and territories to provide the BoM with data on water availability, water flow, water use and water trade. 17
The BoM assists the MDBA and the CEWH in implementing the Basin Plan by providing a range of data and information, including information regarding recent climate conditions, climate outlooks, data relating to heatwaves, fire danger, soil moisture conditions and significant climatic events, water storage levels and water allocation and entitlement trade.18
The South Australian Royal Commission noted that there had not been an assessment of the climate risks to the Basin in developing the plan, or since its implementation. The Royal Commission therefore recommended that the MDBA, or another appropriately funded body, conduct a review on climate risks to the Basin.19 The Royal Commission also recommended that there should be urgent research undertaken as to how the Basin can best adapt to climate change.
The MDBA has noted that the objective of their climate change program is to build understanding of, and capacity to analyse, climate change ahead of the major Basin Plan review in 2026.20
The MDBA are currently working in partnership with the independent Advisory Committee on Social, Economic and Environmental Sciences (ACSEES) to design a research program to improve understanding of climate change.21
On 1 September 2019, Minister Littleproud announced a $20 million study into climate change, ecology and hydrology in the Murray-Darling Basin. This program, which will be completed over four years, will further coordinate research that’s already happening, and aims to increase knowledge around the Basin to help better inform water and environmental management decisions and improve outcomes for communities.22

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