1. Study site: Wharf Street Drainage Nutrient Intervention Project
The Wharf Street Wetland and Civic Centre Parklands captures and treats storm water and groundwater from the main drain, located in the greater Canning Plain Catchment. The main priority of this wetland catchment was to capture and remove nutrients and other pollutants from the storm water before entering the Canning River. The project on Wharf street is an offline system which diverts storm water out of the storm water pipes and out into the Wharf street wetlands. The Wharf street wetland project is an offline system that diverts the water to a series of open water, vegetation swale, and subsurface wetlands which are essentially gravel pits. (…video…) The Wharf street project is located south of the river in Cannington. The area is highly residential with commercial zones nearby and the Canning river which people value the qualities of. However, with wetlands being so close by to the residential areas, it brought upon environmental, social and aesthetic issues and challenges. These issues and Challenges have been dealt with by the councils and local government, who have come about with solutions to address the problems of the water flow into the Canning River.
Figure 1: Civic Gardens on Wharf street, Cannington.
Environmental issues
Prior to the development of the Wharf street wetlands project, the storm water would go untreated and drained straight into the Canning River which was a major concern towards the community, the environment and the aesthetic quality of the area. The untreated waters draining into the River was a major problem and brought major environmental issues such as pollution and the killing of biodiversity. The main nutrients polluting the river were phosphorous and nitrogen which derived from fertilisers used in agriculture and gardening. Acid sulphate sediments from which derived from industrialized areas where also polluting the river. Prior to construction of these wetlands, the contaminated water flowed out into the Canning River polluting the waters. The process of constructing a wetland, involved the removal of a road and infrastructure that separated the City of Canning council offices from the Canning River Regional Park and access to the foreshore of the river. The process of removing infrastructure causes environmental issues as industrial machinery is used which causes pollution and may affect the biodiversity that exist among the area.
Social, cultural and aesthetic issues
The Canning River is an important feature to the culture of Western Australia. It connects to the iconic Swan River which is the main River of WA. Therefore, is should be aesthetically pleasing and a feature which attracts attention. However, with the environmental issues destroying the river, it lets down the cultural and aesthetic quality of it. Social Challenges have been evident throughout the community, about not being pleased or satisfied with the quality of care or respect towards the land and the river. With the establishment of the Wharf street wetlands in the Civic Garden area, people still have issues with the aesthetic quality of the place, with it not being a pleasant place to be around since its all drainage storm water.
1.1 Discussion: Addressing the issues of Wharf Street Drainage
The project on Wharf street is an offline system which diverts storm water out of the storm water pipes and out into the Wharf street wetlands. As stated before, the Wharf street wetland construction involved the removal of a road and infrastructure. However, the removal of the road and infrastructure was replaced with a functional wetland to capture and remove pollutants and nutrients before entering the Canning River, and a grassed area with a barbeque and seating, and a path were also placed to improve the social status of the area. This uplifted the social issues aroused throughout the Community. People can now come together for a meal, or for a walk and socialise and have a sense of cultural community in an aesthetically pleasing environment. The wetland has helped decrease pollution of nutrients into the rivers shown in the 2017 Department of parks and wildlife statistic report…
“The 2015 CRC WSC performance assessment showed that since commissioning, the wetland has removed 129kgof 286kg (or 45%) of phosphorus and 1,658kg of 2,526kg (or 65%) of nitrogen, which has flowed through it, with phosphorus removal being enhanced after the subsurface flow wetlands were brought online “(Department of parks & wildlife. 2017). Stakeholders such as water corporations, the local government, wildlife parks and the community have supported the wetlands project in addressing the issue of the untreated waters flowing into the Canning River. The implementation of strategies for storm water and groundwater management have been developed in response to the proposed redevelopment and the conditions of the site. Therefore, the Wharf street project offers significant value adds to the local area in which it is situated. (Syrinx Environmental. 2000). Wharf Street wetlands has made significant contributions towards reducing contamination.
2. Study site: Bannister Creek Living Streams Urban Waterway Renewal Project
Banister Creek is situated on Banister Creek, adjacent to Bywood Way in Lynwood, Perth. (Water and Rivers Commission, 2002). The creek was originally a series of wetlands, but has been used as a main drain since 1979. Bannister Creek was once a natural system that has been modified to become a drainage network. Most of the water catchment has been cleared for residential industrial and uses. This has altered the waters entering the creek due to the rigid surfaces, such as roads that don’t retain water and it runs quickly into nearby wetlands and waterways. The aim of the project was to transform a section of the drain into a living stream. The main function of the waterway is to collect storm water from urban and industrial areas and treat it from pollutants. The establishing of the site is to raise community awareness and achieve environmental benefits by promoting adoption of different waterways management techniques. (Water and Rivers Commission, 2002). However, before the urban waterway renewal project was established, and after it was done, it created problems and challenges towards the environment, the social/amenities and the local government.
Environmental issues
“The Bannister creek has been severely modified by urbanisation and industrialisation, with very few of the original plant and animal communities remaining. The Catchment’s normal hydrological processes have been radically altered…changes to land use in the catchment have the potential to cause significant changes in processes controlling stream flow and water quality in Bannister Creek” (Fisher, Judith. 1999.). This has caused issues in the quality of the water, changes in the runoff of the water and changes in the amenities such as wetlands. The Creek is always flowing which causes issues with sedimentation and erosion. Since the creek is always flowing, there is no pollution trap and therefor sedimentation enters the creek from nearby building sites.
Urbanisation can have major negative impacts on the Creek itself due to pollutants flowing into it. The following image shows the mixture e of bubble creates by the establishment of pebbles mixed with the pollutants from the nearby industrialised areas.