Managing water in dry times
Healthy rivers and wetlands are the lifeblood of New South Wales. They are essential for the delivery of economic, social and environmental outcomes that impact us all.
Drought conditions pose social, economic and environmental challenges. The Office of Environment and Heritage (OEH) is aware of the difficult times many people are currently facing.
Rivers and wetlands across New South Wales are also doing it tough – they need water too.
OEH is managing the limited volume of water set aside for the environment to ensure essential environmental assets remain viable now and into the future.
As part of its annual planning processes, OEH has prioritised the rivers and wetlands that will receive water over the coming months and years. Our management approach is adaptive. We revisit our priorities as the seasons change from dry times to floods and to the scenarios in between.
Many of our rivers and wetlands are still recovering from the millennium drought. We must manage available water carefully so that we don’t undo any recent gains or have further declines in river and wetland health.
Allowing a key wetland or river to degrade during drought can have long-term and far-reaching consequences. The risks include:
- losing genetic diversity, especially among native fish populations which cannot exist without water. Genetic diversity is not easily fixed by restocking
- losing viable populations of plants and animals of different ages and maturities. For floodplain plants like river red gums, this can take many decades to restore. This has implications for waterbirds, turtles, frogs and native fish as well
- losing or reducing breeding opportunities for flow dependent native animals and plants
- deleting parts of the food chain which then impacts other species
- opening the door to pest species that can capitalise on conditions in a degraded environment and bounce back faster than native species when rain returns. This is especially true of European carp
- interrupting the release of essential nutrients into the aquatic food web which impacts on plant and animal populations locally and downstream
- interrupting the seed bank lifecycle of native plants whose seeds lie dormant in the soil but are lost when water does not arrive
- depleting the availability of food for pollinators, which move from floodplain forests into surrounding farmland and provide important services to the agricultural industry
- depleting groundwater reserves, which impacts plant health and availability of grazing opportunities for nearby landholders.
It is not always possible to recover or restore populations of plants or animals that have been lost. That’s why it is so important to maintain what we have during these challenging times so our rivers and wetlands can remain viable for all water users now and in the future.
How is water for the environment managed during dry times and drought?
OEH manages water across years and seeks to protect important rivers and wetlands through periods of drought. Our teams across the state are now implementing these strategies with the limited water available to avoid critical loss of habitat and ensure the survival of native species including fish, waterbirds and plant communities.
Where water for the environment is not available, OEH is working with partner agencies, such as WaterNSW and DoI Water, to ensure water releases for consumptive purposes can also support the survival of native plant and animals.
What is water for the environment and where does it come from?
Water for the environment is water that is set aside and managed specifically to improve the health of rivers, wetlands and floodplains. This includes the unique native plants and animals that rely on river systems for their survival.
Water for the environment has been recovered across New South Wales by both State and Commonwealth governments. Water is held as licences or water allocations within the NSW water Sharing Plans.
Why do you keep adding water to these wetlands and rivers, even during drought?
Our wetlands and rivers play a vital role in supporting native water-dependent animals and plants. This includes important recreational fish species such as Murray cod and golden perch. It also includes important and rare wetland plants which provide food and shelter for native animals including frogs, turtles, crustaceans, wetland and woodland birds, reptiles and insects. Many of these species are now dependent on water for the environment to provide drought refuges to help them survive the tough times.
It’s not just a matter of keeping things alive. For ongoing survival, native animals and wetland plants need to reproduce and have viable populations to create the next generation to remain in the system.
Dry conditions mean water allocations have been impacted across many NSW catchments. The same rules and allocations that apply to industry and agricultural water licenses also apply to environmental water licences. Everyone who shares in the water resource has less water during drought.
Why have you changed the places you deliver water to? Why aren’t you delivering water to other important waterways?
During dry conditions and drought, priorities for water delivery to environmental assets change. Some sites will end up going dry. This is natural for waterways that have natural wetting and drying phases. Water delivery is prioritised to maintain minimum flow rates and inundation to sites that are identified as critical drought refuges.
A drought refuge is a site such as a river or wetland that provides permanent fresh water or moist conditions for native plants and animals. These refuges are important and act like an oasis, maintaining vital populations of native plants and animals until drought conditions break.
How are watering events planned?
Each year water managers plan watering events according to the seasons, water availability, in consideration of other water users, and the needs of native plants, fish, frogs, birds and other wildlife. Water availability is one of the key considerations when planning where and when water should be used. The four water availability scenarios used in the planning process are shown in the table.
|Very dry||Dry||Moderate||Wet to very wet|
|Main aim: Protect||Main aim: Maintain||Main aim: Recover||Main aim: Enhance|
Who manages the water and decides where the best drought refuges are?
The NSW Office of Environment and Heritage (OEH) manages the delivery of water to key sites across New South Wales including the Gwydir, Macquarie-Castlereagh, Lachlan, Murrumbidgee and Murray-Lower Darling catchments.
OEH consults with stakeholders including community groups, Traditional Owners, recreational fishers, landholders, scientists and government agencies to decide when and where water for the environment is used. These stakeholders form part of Environmental Water Advisory Groups (EWAGs) in each of the catchments. These EWAGs, in conjunction with the latest available scientific research, help to decide where water is used to achieve the best outcomes with the available water.
Why are landholders and primary producers important stakeholders?
OEH works with landholders including irrigators to achieve environmental outcomes on public and private land. Some 80 per cent of wetlands in New South Wales are located on private property. It is essential that we work with primary producers (and other landholders) to achieve the best possible outcomes for rivers and wetlands on a landscape scale.
In the southern basin, OEH works with irrigators to deliver water to wetlands and ephemeral creeks via private irrigation infrastructure. More than 200 irrigators are involved in watering programs. They provide local knowledge and often invest their own time and resources to support outcomes, including opening irrigation channels, tracking flow progress and reporting their observations.
Many primary producers care about their local environment and are advocates for the dual outcomes that can be achieved by working together to deliver water for the environment.