Federation Square Car Park, Melbourne
In terms of urban development, landscapers have to be increasingly innovative in order to make an impact. With most of Australia facing extreme weather fluctuations, planting popular European plants becomes an almost non-existent possibility. Other than green roofing, the space shortage in urban areas places great limitations of landscape opportunities. This is especially relevant in Melbourne where terrace houses are a cultural heritage, compiled against city sky rises offering limited space for effective landscape design.
Compiling these ideas together and serving a greater purpose are the increasingly popular rain gardens. Although the idea of these sections of landscaped areas only came into vogue around ten years ago, they are proving to be vital in terms of city water planning. Melbourne and Sydney have used the rain garden principle in their water saving and landscaping planning, the idea also proving incredibly popular across America.
Rain gardens are essentially areas that allow for run off from gutters, houses, driveways and foot paths to be absorbed. This is proving to be increasingly important in urban areas as it reduces the toxicity of run off water, as well as filtering it before it goes through drains to waterways. Not only is this allowing more water into suburban soils, it is decreasing the pollution in nearby waterways by approximately 30%.
Already, major cities in Australia have taken up the idea with positive results. Last year the City of Sydney Council commissioned 21,000 sqm of space for rain gardens in order to cut down on the storm water entering the harbor, as well as promoting sustainability in the city. Initial projects were so effective spreading across the areas from Buckland St. to the Glebe foreshore; a further $3 million was put into Parklea in order to create a rain garden that would filter water at a new housing project.
Here in Melbourne the City Council is using the rain garden initiative as a way to save water, as well as cut down on pollutants flowing into the Port Phillip Bay and the Yarra River. With 735 rain gardens already being seen city wide, and with a goal of ten thousand, it is clear that Melbourne is committed to the rain garden initiative. Two major projects that the council in association with Melbourne Water have developed through the Yarra River Action Plan are the Federation Square Rain Gardens and the Acland St. Rain Gardens.
Melbourne Water case studies of the two projects explain the ideology behind the projects, as well as what the results have shown.
Constructed as apart of the plan formed at the Melbourne Water “Yarra River Youth Conference 2007”, the project at Federation Square in the centre of Melbourne was created to catch and treat run off from the car park’s roof.
Specific plants and soils are now breaking up drainpipes that were initially connected to further piping that sent storm water directly into the Yarra River. These plants and soils break up the pollutants in the water, filter it, and allow it to soak through into an underground pipe, which catches the filtered water and takes it to the river. Although the benefits are small in the initial stages, Melbourne Water says that the project is promoting sustainability and awareness on a community level.
The second project at St. Kilda’s Acland St. was initiated after trees in the area were found to be poorly irrigating soils, were in poor health, and were becoming a hazard for pedestrians. Due to the urban nature of Acland St., building up gardens on the footpath was not an option. Instead, permeable tree grates and pits were constructed into the sides of roads in place of original drainpipes. The tree species, Japanese Zelkova, were planted in the grates due to their hardiness and ideal qualities as storm water filters. Again the trees and their soil are breaking up the storm water before it reaches the drains below, becoming a natural filtering system. The trees and storm water are proving to be symbiotic. The trees are being fed by the nutrients in the water as they are filtering it.
This innovative and sustainable filtering system is leading the way in terms of urban landscaping. It shows a clear initiative that allows for plant and tree growth in even the most built up city areas.
Image: as sourced from Melbourne Water online