Topics > Water > Water resources > SE Drainage Network

Environmental management

Wetland and watercourse protection

The South East drainage and floodway network aims to protect and enhance wetlands and watercourses in the South East by:

  • providing fresh water flows to water-dependent ecosystems
  • minimising the negative impacts of waterlogging and/or salinity on ecosystems
  • annually monitoring the condition of wetland areas.

In the Upper South East, the drainage network gives us the ability to separate saline groundwater from fresh water. Saline groundwater is transferred through the network to the Coorong. Fresh water is used as environmental flows, including diversions to the REFLOWS Floodway which recreates the natural historic south to north flowpaths across the region.

Adaptive management

Operating decisions are made according to the principles of adaptive management, which simply means ‘learning by doing’ and ensures continuous improvement. It includes a rigorous program of planning, operating, monitoring and improvement.

Each year pre-winter, objectives are set for the annual management of the system. Examples include delivering environmental flows to priority wetlands and ensuring the operation of a key regulator to minimise inundation of an at-risk agricultural area. The system’s winter/spring operations are run to achieve the management objectives and each operation (e.g. the lifting of a regulator) is recorded for subsequent review.

A hydrological monitoring network allows operators to manage the drainage system in response to catchment conditions and rainfall. Ecological monitoring captures the response of wetland ecosystems using the numbers and variety of vegetation, waterbirds, fish and frogs as key indicators.

Management agreements

Management agreements were established under the previous USE Act. The South Eastern Water Conservation and Drainage (SEWCD) Board is now responsible for these agreements for a number of purposes that include:

  • the conservation or management of water, or the management of any water table
  • the preservation, conservation, management or re-establishment of any key environmental feature
  • any other matter associated with the implementation of the project or furthering or enhancing the project undertaking.

To date, remnant natural environments have been safeguarded through the negotiation of formal management agreements with landholders for the care of biodiversity assets on their land. As at 30 June 2012, a total of 156 management agreements had been negotiated between the Minister for Water and various landholders relating to stewardship covenants over 18,500 hectares of land.

Operating the system

The SEWCD Board operates the South East’s drains and floodways.

The drainage system is operated to:

  • protect infrastructure, land, soils and ecosystems from flooding and dryland salinity
  • provide water for environmental purposes to enhance the natural environment
  • protect and enhance South East agricultural lands for primary production
  • assist in the proper conservation and management of water in the South East.

Prolific growth of rushes and other vegetation in drainage channels encourages silt deposits. The SEWCD Board maintains 2589 kilometres of drains and associated structures through a comprehensive annual maintenance program. This program includes machine cleaning of silt deposits, control of vegetation obstructing flows and regular attention to road bridges and other structures.

See our fact sheet on operating the South East drains and floodways.