About The Wetlands

History

Why an Urban Wetland?

In July 1993, the City of Mitcham Council carried out a study of the storm water drainage system along Cross Road. It is here that two large pipe systems join into a single pipe under Cross Road and the stormwater flows into the Patawalonga outlet and then into the St Vincent Gulf at Glenelg.

Due to increasing areas of hard surfaces like roads, rooves and paved areas in this catchment area the volume of stormwater flowing through this system was too large for the pipe system resulting in regular flooding of some of the farm land of the Urrbrae Agricultural High School as well as the local streets. As a result, it was decided that a water retention basin should be constructed by diverting the water from the two inlet pipes into a wetland to be constructed on the Urrbrae site. An outlet pipe could then regulate and deliver the overflow water from the Wetland into the existing stormwater pipe under Cross Road at a rate that would avoid the flooding.

Funds to build the Wetland were provided by the City of Mitcham, Department of Transport and the Patawalonga Catchment Board. The land itself is part of Urrbrae Agricultural High School and is owned by the Department of Education. The flood mitigating facility is currently managed by the City of Mitcham with Urrbrae Agricultural High School managing the education aspect of the site. The volunteers, Friends of the Urrbrae Wetland, manage the vegetation and some of the general maintenance of the site under the guidance of the City of Mitcham Council and the Wetland Manager.

The Wetland site was opened on April 9th, 1997.

Our Vison

Our Vision Science with Practice
To develop, promote and deliver specialist and engaging environmental educational programs for school students, tertiary students, teachers and community members. The cross-curricular programs will combine field experiences at Urrbrae Wetland with classroom based lessons to enhance learning experiences and allow the acquisition of a diverse range of viewpoints to help understand environmental issues.

Objectives

  • To promote an awareness and understanding of wetlands in urban areas through hands on learning experiences, which encourage sustainable practices and values.
  • Offer programs across the curriculum that are authentic, practical and engage students in learning activities.
  • To equip visitors with the skills to take positive actions towards a sustainable future.
  • To utilise information, communication technologies as an educational tool to connect Urrbrae Wetland with outside schools, universities and other organisations which encourages the sharing of information to achieve better sustainable and conservation outcomes for Urrbrae Wetland.
  • Promote a better understanding of the values, functions and benefits of wetlands in urban areas.
The Wetlands Today

The wetland is visited by over 6000 people including students from kindergarten to tertiary levels and various community groups each year. These visits provide opportunities to learn about how the wetland works as well as the importance of the natural environment surrounding the wetlands.

The wetland also has several Open Days a year which are run by their dedicated volunteer group. These provide any members of the community the opportunity to enjoy and discover the wonderful environment of this unique wetland.

For more information about go to bookings

How the Wetlands Work

Function of the Urrbrae Wetland includes:

  • The cleansing of the stormwater by, filtering out large debris through the trash racks.
  • The water flow is slowed down causing the sand and sediments to fall to the bottom, this is called sedimentation.
  • Heavy metals, salts and bacteria are removed as they “stick’ onto the falling particles, this is called flocculation.
  • Reeds, sedges and other native plants that make up the riparian zone, filter out a lot the of salts and heavy metals.

Flood Provention
The wetland ponds hold up to 17.7 million litres of water (that’s over 7 Olympic swimming pools). With large rain events it has the capacity to hold an additional 17 million litres by filling the ephemeral ponds and swelling up the banks.

Provides an aquatic habitat
The wetland has been planted with may different species of local plants, providing a home for numerous species of birds, reptiles, amphibians and  macroinvertebrates.

Provides the community with unique, educational programs
The Urrbrae Wetland offers authentic and engaging learning opportunities for every  age group in any learning area.

Copying nature – designing a wetland
The Urrbrae Wetland is a man made, permanent wetland with some ephemeral ponds in the surrounding areas. These ephemeral ponds demonstrate what a natural wetland would be like as they often dry out during summer. The wetland itself has four main areas of water including the main pond (holding 13.5 million litres of water), the two sedimentation ponds (together holding 1.2 million litres) and the farm dam (holding 3 million litres). The main pond area can be anywhere up to 3m deep when the wetland is full and each pond helps the wetland function effectively as a flood controller and storm water filter, but this hasn’t always been the case.

When the wetland was first built the sedimentation ponds were not include so the stormwater ran straight into the main pond. Students from Urrbrae Agricultural
High School were involved in conducting depth profiles of the main pond along set transects, and soon discovered that the maximum depth had plummeted from 3m to 2m in only five years. As a result of their findings the two sedimentation ponds were added in 2003.

The Big Picture
While the wetland only covers an area of approximately 6 hectares, its catchment area is around 380 hectares (see below). That means that any drop of water, which falls in this catchment area could potentially end up in the wetland, along with many different pollutants. Prior to the establishment of the Urrbrae Wetlands the water and its pollutants flooded local areas, before flowing into the Brown Creek Catchment, the Patawolunga then out into the Gulf of St Vincent. However the wetlands stops much of the pollutants from continuing their journey, through a number of different methods including sedimentation, filtering, nutrient up-take, organic oxidisation and UV sterilization.

Creating a safe home
As well as controlling and cleaning stormwater, Urrbrae Wetland also provides an invaluable habitat for a wide variety of animals including over 50 species of birds. These animals are able to find refuge in their urban surroundings because the wetland is planted with over 100 different species that are considered ‘local’ or endemic to the area; meaning they are believed to have grown in the area prior to European settlement in 1836. The overall landscape represents a ‘grey box grassy woodland’, containing tall trees, shrubs, grasses, shoreline plants and aquatic plants.