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The Brooklands Wetland

Description
The Brooklands Wetland is a protected area in Orange, NSW Australia. It is situated near the northern edge of the city, between Kearneys Drive and the junction of the Northern Distributor Road and Burrendong Way. This lacustrine wetland was initially an ex-pasture naturalised swamp, with a braided freshwater stream–swamp running through the centre from east to north-west. In an effort to combat the effects of current and future dry periods, the Orange City Council has constructed artificial wetlands in the north-western end to store and harvest the increased stormwater runoff associated with increased urbanisation.

Soil and climate
The soils of the wetland area are generally silty clay and sandy clay topsoils, with partly gravelly subsoils. Coarse shale can be found at depths greater than 1.8m, and all soils are moist to wet. Orange itself has a cool climate, particularly as due to the its altitude of 850m above sea level. Evenly distributed rain allows a variety of plants to grow throughout the year.

Ecology
Historically, the Brooklands Wetlands was a pasture area, and as a consequence of the habitat destruction a lot of native species were lost. Many of the plants in the Brooklands Wetland are adapted to, and reliant on, the perennial waterlogging of the area.

Wetland planting
Native flora has been planted around the constructed wetland, such as Lomandra longifolia, Pennisetum alopercuroides, Gahnia sieberiana, Juncus usitatus, Juncus aridicola, Poa labillardieri, Baumea articulate, Bolboschoenus fluviatilis, Carex appressa, Carex fasciularis, Ottelia ovalifolia, and Eleocharis sphacelata. The wetland habitat has been planted with the aim of attracting a diverse range of wildlife, providing niches for feeding, nesting, and breeding in a variety of plant and water habitats, including the deliberate construction of shallow areas for wading birds.

Surrounding flora and fauna
Native eucalypts have been present since before the stormwater collection area, and these populations have been added to with plantings of sheoaks, tableland casuarinas, and yellow box gums. Local populations of adult Eucalyptus viminalis provide structural diversity, as well as established natural regeneration. Phragmites australis is present in large numbers and aids in slowing water flow. A large variety of plants species are present including Leptospermum, Typha, Lomandra, Pennisetum, Carex, Acacia, Vicia, and Poa. Many native and naturalised animals are found in the Brooklands Wetland, including fairy wrens, blue tongued lizards, Japanese snipes, striped marsh frogs, Peron’s tree frogs, and Banjo frogs. White-faced and Lesser herons, ibises, sulphur-crested cockatoos, galahs, starlings, blackbirds, magpies, magpie larks, crested doves, purple swamp hens, Australian wood ducks, miners, currawongs, and crows are all regularly seen in Brooklands Wetland and the surrounding swamp. Macroinvertebrate surveys have shown the presence of a variety of species including midges, water mites, stonefly larvae, dragonfly larvae, damselfly larvae, freshwater shrimps, yabbies, and backswimmers.

Environmental threats
When the Brooklands Wetlands were constructed, it was acknowledged within the plan that removing water from a system will have a downstream impact. As a result, the stormwater harvesting scheme was presented with a challenge to adaptively manage the use and extraction of stormwater so keep the downstream impact below a significant level. Upon completion, the wetlands were successfully constructed without serious or irreversible damage to the health, diversity, productivity and integrity of the environment, reducing the overall environmental threat associated with construction. Overall, an ecologically sustainable yield has been established for this protected area, taking into account the environmental variability associated with climate and weather patterns.

Local environmental threats to this protected area include the surrounding urbanisation: the chemical runoff associated with urbanisation, the litter from surrounding houses and pedestrians around the outside of the wetland, the pollution and potential road kill resulting from the nearby heavy-traffic road, and the large volume of sediment associated with upstream erosion. Biological environmental threats include the presence of non-native animal pests such as foxes, feral and domestic cats, and invasive plant species such as blackberry, St John's Wort, Patterson's curse, pyrocantha, umbrella sedge, Hawthorn, Phalaris and Rumex. Pest mosquito fish were introduced to Australia in the 1920’s and have migrated to the wetland.

In addition, the overall management of environmental water benefits rivers and wetlands, ensuring they have sufficient water to support the inhabiting plants and animals in a varying climate. The stormwater retention dams forming the main body of the Brooklands Wetlands ensure that there is permanent water for the ecosystem, particularly as these areas would otherwise dry out and stress their inhabitants. Despite the purpose of the Brooklands Wetland as a stormwater harvesting scheme, pumping of water is controlled with flow measurement devices and level sensors which adjust pumps according to water availability.

Protection and management
The NSW wetlands policy promotes sustainable conservation and management of wetlands, and encourages stakeholders to cooperate in wetland ecosystem and catchment protection. Protection of wetlands is important as wetlands reduce the risk of flooding, improve water quality through sediment trapping and filtering out pollutants. Prior to wetland establishment a different department of the Orange City Council dug a channel along the northern edge of the swamp in an attempt to “mitigate flood damage” due to the increase of houses built along the floodplain. This caused problems with the first few flood events once the Brooklands Wetland was constructed, as the influx of fast-flowing sediment associated with the channel’s erosion inundated the stormwater holding dams, reducing water and habitat quality. Since then, the planting and confirmed establishment of water-slowing plants such as river tussock and phragmites have mitigated this problem.

Continuous monitoring and evaluation provide important tools in determining the health of the Brooklands Wetland; the Orange City Council Wetlands, Weeds, and Wildlife section regularly inspects the wetland for infestations of noxious weeds and quickly removes any imminent problems. The implementation of a gross pollutant trap at the stream’s entrance into the wetland prevents the entrance of litter into the water-holding dams. As the majority of the water entering the wetland is urban runoff, the establishment and confirmation of the Trade Waste Agreement preventing harmful substances such as metals and pesticides entering the system has been essential in protecting this wetland. Wetlands, due to their densely-covered and boggy nature, can reduce the impacts from storm damage and flooding. These areas also work to maintain the health of river and ground water.

The different zones within the artificial wetland (inlet, deep water, macrophyte, outlet, and littoral) have all been constructed with components to trap litter and larger pollutants, dissipate energy, capture sediment, protect the banks and wetlands, and improve overall aesthetics which in turn improves value to surrounding residents. This is important as public opinion and value of a local protected area has a significant impact on its success ; the Brooklands Wetland has been very successful with the aid of neighbouring residents assisting in planting, maintenance, and monitoring. Many native species reside in the Brooklands Wetland, and with increased urbanisation this protected area provides a variety of habitats as well as ecological connectivity.