An introduction to water for the environment

What is water for the environment?

Water for the environment, or environmental water, is surface water or groundwater which water managers use to maintain or improve the condition of the environment.

• Surface water for the environment is largely used to improve the conditions of rivers, wetlands and floodplains.
• Groundwater for the environment is largely used to protect ecosystems that depend on wetlands, springs, caves, and coastal sand dune systems. It can also help provide important flows to rivers and tidal creeks.

Water for the environment includes both planned environmental water and held environmental water.

• Planned environmental water is water that is reserved for the environment in a water sharing plan. Planned environmental surface water is either kept in the system or released from dams to improve environmental outcomes, while planned environmental groundwater is usually kept in the system to protect ecosystem health.
• Held environmental water is water that is purchased with a licence to be used for environmental purposes, in the same way that a person may purchase water to irrigate crops.

Why do we need water for the environment?

Over time, humans have altered the condition of our rivers, wetlands and floodplains. Among other activities, we have built dams and weirs, diverted and straightened waterways, built on floodplains and drained wetlands for farming. Humans have also taken water from rivers and groundwater for use for our crops and homes.

This has affected the health of our waterways, and the health of the plants, animals and other organisms which rely on them to survive. It also affects the wellbeing of Aboriginal people, who have cultural and spiritual ties to waterways.

Planning and delivering water for the environment is one way to maintain and improve the health of our river systems. It helps to reduce the negative effects of human activities on rivers, wetlands and floodplains.

How does water for the environment help restore rivers?

Dams and weirs interrupt the natural flow cycles which occur in rivers and streams. By releasing water for the environment at strategic times, water managers can help to mimic the patterns of natural flows. These patterns can help cue feeding and breeding behaviours for plants, animals and other organisms in the water system, which help them survive. During dry times, releasing water for the environment can also help to maintain drought refuge pools to support living creatures.

Water released for the environment in surface water systems can also improve the connectivity of the water system. Connectivity is a measure of how much the water in a river or stream is connected down its length, to the surrounding floodplains and wetlands, and to underlying groundwater sources. It helps to maintain healthy water conditions, move nutrients and sediment down the river, and allow native fish and other organisms to move around.

In groundwater systems, retaining water for the environment in the system can help protect the health of groundwater dependent ecosystems. These can include ecosystems based around wetlands, springs, caves, and coastal sand dune systems. It can also help to provide important base flows to connected surface water systems like creeks and rivers.

Who manages water for the environment in NSW? How do they do it?

Both the NSW and the Commonwealth government have agencies which manage water for the environment - NSW DCCEEW Biodiversity, Conservation and Science Group and the Commonwealth Environmental Water Holder are environment water holders, while NSW DCCEEW Water Group and Murray Darling Basin Authority develop and implement environmental water policies. These agencies work together to deliver environmental water in ways that best support the environment.  Find out more about who is responsible for managing water for the environment.

Deciding how, where and when to deliver water for the environment is complicated. Priorities for water for the environment are set in water sharing plans, but physically delivering it is complex. Each year, agencies responsible for water for the environment plan how to deliver it to best help the environment. But their plans have to consider issues like:

• the availability of water, and the expected weather that year
• how much water the environment needs, when and where
• how to get the water where it needs to go
• rules and regulations
• climate change, and planning for droughts and floods.