What is water for the environment?

Water for the environment, also known as environmental water, e-water or environmental flows, is water allocated solely for the purpose of achieving environmental benefits and improving the health of our rivers, wetlands and floodplains.

In South Australia, water for the environment is managed and delivered by the Department for Environment and Water (DEW) and local landscape boards, with the goal of restoring the health of rivers, wetlands, and floodplains by delivering water when and where the river’s ecosystems need it.

Specific goals for watering at each site along the River Murray are based on scientific advice, investigations and past monitoring results, and are decided with Traditional Owners and local communities.

Why do we need it?

Starting in the early 1900’s, the River Murray’s channel, wetlands and floodplains were modified to ensure a more consistent water supply for critical human needs, navigation and agriculture. This river regulation and water management heavily reduced the river’s seasonal flow regime and the availability of water for the environment, which are both required for river ecosystems to thrive.

As agriculture, industries and communities have grown over time, water use has increased dramatically, further impacting the waterways and preventing them from functioning as they naturally would. This has resulted in the degradation of the river system and the decline of keystone flora and fauna species.

To aid in restoring the river system, we need to actively manage how water flows through it. These flows are called ‘water for the environment’ and are critical to restoring the Murray-Darling Basin’s long-term health.

Water for the environment provides many benefits, including keeping the Murray Mouth open, flushing salt from the system and providing additional water to precious wetlands and floodplains, which need a varied flow regime for their ecosystems to thrive. It also benefits ecosystem functions like nutrient cycling, soil development, biodiversity and water quality.

Water for the environment creates flows through the anabranches of the river and over riverbanks, which connect habitats along the floodplain with one another and the main river channel. Such connections maintain shorebird habitat and enable aquatic species to access refuge areas, find breeding partners and recolonise suitable habitats, all of which are important for species’ long-term survival.

Benefits

Environmental

• Improved connectivity between riverine and floodplain habitats
• Localised freshening of groundwater systems
• Watering of native vegetation including red gums, black box and lignum
• Improved soil conditions due to floodplain watering operations flushing salt
• Increased sustainability of tree populations through supporting seedlings with more frequent watering
• Increased food resources, such as waterbugs and aquatic plants, for fish, yabbies and waterbirds
• Increased food resources and habitat for native terrestrial animals such as bush birds, reptiles and bats, through improved condition of floodplain woodlands
• Increased opportunity for successful breeding and recruitment of fish such as Murray cod and golden perch.

Community

• Opportunities for recreational activities such as fishing, boating and birdwatching
• Sustained healthy Country for First Nations communities
• Improved water quality and flow-on economic benefits for farming and industry

How do we know it works?

The effects of water for the environment are measured and monitored at many sites before, during and after each watering operation, and we draw on a large body of scientific and community knowledge to measure success.

Monitoring involves observing, recording and evaluating releases of water over time. From the results, we can understand how the physical and biological parts of the river system respond to changing water and flow conditions.

Monitoring data is collected by government agencies, research organisations, First Nations communities, volunteer groups and the Murraylands and Riverland Landscape Board, with data recorded in outcome reports and used to inform the planning of future watering decisions.

Types of monitoring

Real time (operational) monitoring

Occurs during an environmental watering operation and is often frequent (weekly or even daily). The information allows us to change how the water is delivered as it is flowing.

Monitoring activities include:

• measuring water levels and salinity at surface water monitoring stations located along the SA River Murray channel, floodplains, Lower Lakes and Coorong lagoons. Some stations also measure dissolved oxygen, water temperature, flow direction and turbidity
• collecting data on gate openings, water levels, and discharge volumes through pump and regulator operations.

Ecological monitoring

Occurs at many watering sites, with data collected on:

• the health and abundance of native fish, waterbirds, frogs, invertebrates and aquatic vegetation
• tree condition (particularly red gum and black box communities)
• groundwater and surface water quality.

System-scale ecological monitoring

For Basin-wide information, including the Lower Murray, visit the Commonwealth Environmental Water Holder's on-ground monitoring, evaluation and research program (Flow-MER).

Does environmental watering affect irrigators?

Water for irrigation is not affected by environmental watering operations, as water for these are sourced from specific environmental water allocations.

Operations are carefully managed to minimise the risk of water quality issues such as algal blooms or black water.

Does watering affect river salinity?

Watering operations may temporarily increase the amount of salt entering the River Murray, in the same way natural floods can. This can cause saline groundwater to flow into the river.

The impacts of short-term increases in salinity are minimised by:

• reducing the level and length of floodplain watering operations when there are salinity risks
• only delivering water for the environment when water flows are high enough to dilute salt levels downstream of regulators
• tracking salinity levels to ensure they remain under certain thresholds.

While there are short-term impacts from increased salinity, In the long-term, water for the environment actually reduces salt build-up in soil and improves the health of the floodplain and river system.