Managing environmental water
Managing water for the environment is complex and requires environmental water managers and river operators to consider:
- the availability of water
- environmental requirements
- delivery of environmental water
- rules and regulations
- climate change.
Availability of water
The availability of water for the environment varies from year to year and is dependent upon weather conditions, the volume of water in storages, river flows and catchment conditions and entitlement levels. This means the management of water for the environment needs to be flexible and adaptable. It is important for environmental water managers to plan for a range of conditions so that they use water for the environment as efficiently as possible.
For information about availability of water including water allocations, current conditions, outlook and supplementary water availability visit Allocations & availability.
Each section of the river is unique and has different flow requirements to keep the native plants and animals healthy. The timing, duration and amount of water required by each section also varies depending on the current condition of the landscape and the watering needs of the plants and animals at that particular point in time - for example, migration of Silver perch.
Annual Watering Plans
The NSW Department of Planning and Environment–Environment and Heritage develops Long term Watering Plans for the five catchments (Gwydir, Lachlan, Macquarie-Castlereagh, Murray and Lower Darling and Murrumbidgee) where they actively manage water for the environment. These plans are based on advice received from Environmental Water Advisory Groups (EWAGs).
The plans outline the priorities for use of water for the environment over the coming year and consider factors such as the recent climate conditions and water availability.
Long Term Environmental Water Plans
The NSW Department of Planning and Environment–Environment and Heritage are also developing Long Term Environmental Water Plans to meet Murray–Darling Basin Plan requirements. These plans draw on local, traditional and scientific knowledge to guide the management of water for the environment over the longer term.
Nine plans are being developed for all NSW Murray-Darling Basin catchments and will set objectives for five, 10 and 20 year time frames.
The plans set objectives, targets and watering requirements for key plants, waterbirds, fish and system functions.
Delivery of environmental water
Over the past 100 years, we have changed the river systems to make water available for irrigation, industry and domestic purposes. This regulation of the river has disrupted the natural flow patterns and affected the environment. To improve and maintain the health of the environment, we must be able to deliver water to the environment efficiently and when and where it is needed most.
Using water for the environment is most effective and efficient when it is used in response to natural cues such as rainfall and runoff. In these circumstances timing of releases of water for the environment is critical in order to maximise river height and replenish floodplain habitat. Because our rivers are highly regulated, particularly in the southern part of the Murray-Darling Basin, delivering water for the environment to coincide with natural flows is difficult, and often requires coordination across states.
Water delivery is also subject to timing and volume limits due to physical, operational and management constraints. It takes a lot of planning and coordination to ensure that the environment receives water where and when it needs it most.
As part of the implementation of the Basin Plan, the Murray–Darling Basin Authority has put forward a strategy to manage constraints. In the context of the Basin Plan, a constraint is any rule or structure which limits the volume or timing of the delivery of environmental water. Constraints can include physical structures, river management practices, and operational limits to river heights. Easing constraints contributes to greater efficiency in the use of environmental water. NSW is progressing projects in the southern Basin that manage physical constraints through supply measure projects and those that are rules based through implementation of prerequisite policy measures. In the northern Basin NSW is considering constraints management as part of the northern Basin toolkit and will be implementing active management in some northern Basin unregulated rivers to achieve better management of environmental water commitments under the Water Reform Action Plan.
To find out more about delivering water for the environment including who the delivery agencies are and the structures used to deliver water, visit the Murray–Darling Basin Authority website.
Rules and regulations
Water sharing plans
In NSW the water sharing plans set out planned environmental flow rules and contain other provisions for the protection and management of planned environmental water. These rules vary between valleys, and according to whether they are regulated or unregulated rivers or groundwater sources and focus on the objectives that are most important for each water source.
The planned environmental flow rules in the water sharing plans are designed to:
- limit extraction to protect a share of water for the environment
- replicate natural flow patterns or events to provide water when and where it will meet environmental needs.
The planned environmental flow rules are based on the broad river flow objectives. They set out 12 aspects of flow considered critical for the protection or restoration of river health, ecology and biodiversity.
Each water sharing plan also includes specific rules for the operation of water access licences. These rules apply to all licence holders, including environmental water holders, and include how allocations are made, extraction limits, water allocation account management rules (for example, carryover and take limits), conditions governing water extraction and trade rules. View more information on Water Sharing Plans
Water management in the Murray–Darling Basin
The Murray–Darling Basin is the catchment for the Murray River, Darling River and all their tributaries. It covers most of inland NSW and extends from Queensland through to South Australia.
In an effort to improve the environmental outcomes of the Basin as a whole, the states agreed on the first Murray–Darling Basin Agreement – (schedule 1 of the Water Act) in 1987.
In 2012, the Murray–Darling Basin Plan (the Basin Plan) was developed to manage the Basin in its entirety and as a whole connected system for current and future generations. The Basin Plan determines the amount of water that can be extracted annually from the Murray–Darling Basin for consumption, including urban, industrial, and agricultural uses. This volume is called the Sustainable Diversion Limit and represents a volume that can be used while also ensuring the delivery of environmental outcomes and the function of the rivers, waterways, groundwater, and wetlands of the Basin.
To assist with the management of water in the Basin the NSW Government is developing 20 water resource plans (WRPs). The water resource plans have a fundamental role in ensuring that the sustainable diversion limits for our water resources (as set by the Basin Plan) are implemented from 2019 onwards. The water resource plans set out arrangements for sharing water for consumptive use, establish rules to meet environmental and water quality objectives and take into account any potential and emerging risks to NSW water resources.
More information on water resource plans including access to fact sheets on:
- Maintaining the protection of planned environmental water - surface water
- Specifying planned environmental water
- Compliance with sustainable diversion limits for groundwater
- Sustainable diversion limit compliance for surface water
- Active Management to share flows
Changes in global and regional climate patterns are affecting water availability for communities and the environment of NSW. Climate change is a complex process because many of the effects are uncertain and the timeframes are unclear.
Most climatic projections suggest an increase in the frequency and severity of drought in NSW. Conversely heavy rainfall is also expected to increase.
The NSW Government is planning for climate uncertainty and is developing regional water strategies that bring together the best scientific information and use that data to plan and manage the short- and long-term water needs of each region. The strategies consider how much water a region will need to meet future demand and suggest ways to manage risks to water availability and security. Find out more about regional water strategies being developed across NSW.
To find out more about climate change in NSW, including understanding and adapting to climate change impacts, visit Understanding and adapting to climate change impacts.
If you would like to explore Australia's projected climate and access model data and learn about observed climate change over Australia visit Climate change in Australia.