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Construction and rehabilitation of wetlands

The rehabilitation and construction of wetlands and other treatment systems is undertaken for a wide range of reasons. Wetlands are often rehabilitated to return a system to its natural (or near-natural) state, to enhance opportunities for wildlife, or for recreational purposes. The construction of wetlands may occur for similar reasons e.g. replacing a previously removed catchment, pollution management, erosion control or water storage.

Wooden pile fields can be used to slow down water flow Photo by Matthew Griffiths

Quick facts

Natural
wetland systems have been described as the ‘earth’s kidneys’ because they effectively filter pollutants from our waterways and improve water quality. Engineers and scientists construct similar systems that replicate the filtering functions of a natural wetland.

The first steps in rehabilitating and constructing wetlands are to determine the:

  • type of wetland required
  • aim of the project
  • desired function for the wetland.

Identifying the values—or reasons why the wetland is important—is critical in developing the design. The Queensland Wetlands Program has developed a range of tools to help determine the best approach to the wetland rehabilitation or construction project.

Constructed wetlands

Constructed wetlands are artificial systems designed to mimic certain conditions of natural wetlands. Like natural wetlands they have the potential to regulate levels of sediments, nutrients, metals and pathogens in water.

Constructed wetlands can be built for a variety of different purposes. Most are designed to treat stormwater or wastewater. Others can be designed to provide habitat and aesthetic values. A knowledge of wetland plants, soil and microbial life, and wetland processes is essential for building a wetland for any purpose.

Water movement

Wetland construction requires a balanced approach between engineering, ecology, landscape design and natural resource management. In general, constructed wetlands are designed to use gravitational energy to move water. It is important to ensure that flow rates are not excessive, as high flows—especially during rainfall events—can stir up sediments and impede nutrient removal by destroying wetland vegetation. It may be necessary to incorporate design solutions to control flow rate. The key factors to water purification are the wetland plant communities and the amount of time the water spends within the wetland system. In general, the longer the water spends in contact with plants and the bottom of the wetland, the more effective the treatment.

Water treatment

The keys to water purification are the wetland plant communities and the amount of time the water spends within the wetland system. In general, the longer the water spends in contact with the plant roots and/or wetland substrate, the more effective the treatment.

A stone pitched weir outlet enables vegetation to be incorporated in the design (Figure courtesy of South East Queensland Healthy Waterways Partnership, 2006).
Schematic of a sub-surface flow wetland (Diagram courtesy of Dirou et al 2003)

Treatment and constructed wetlands

Find out more on the treatment systems page.

Additional information

The Wetland Management Handbook is a useful resource, providing information and advice on planning, designing, constructing, management and maintenance of constructed wetlands.

National Standards for the practice of Ecological Restoration in Australia

Fact sheets

Queensland guidelines

Journal articles

Other States, Australia and international

Pages under this section


Last updated: 30 August 2016

This page should be cited as:

Construction and rehabilitation of wetlands, WetlandInfo 2014, Department of Environment and Heritage Protection, Queensland, viewed 12 September 2017, <https://wetlandinfo.ehp.qld.gov.au/wetlands/management/constructed-wetlands/>.

Queensland Government
WetlandInfo   —   Department of Environment and Heritage Protection