Rainwater becomes surface runoff when the ground can’t soak it up fast enough. Even if the earth is cracked and dry, a downpour will fall faster than can be absorbed; hence, flash floods and overflowing sewer systems. The problem we have today is that impervious surfaces, such as car parks, sidewalks, and city buildings take over so much ground that the water cycle is disrupted, causing flooding and erosion. And stormwater collects oil, fertiliser, and litter on its way, further polluting the environment.
As a result, city councils are now forced to restrict impervious surfaces. In applying for building permits, the size of a lot, driveway, or pathway can be constrained by these new restrictions. A green solution is to divert the rainwater to soft landscaping with porous surfacing. Many cities have found that permeable paving and other green paving practices are less costly than restructuring stormwater drain systems.
Holistic concepts such as Water Sensitive Urban Design (WSUD) and Integrated Water Management (IWM) call for the integration of urban planning and development, including water supply, wastewater, stormwater, and groundwater management.
City Councils are proactive in improving the ecological management of urban stormwater under the State Environmental Protection Policy – Water of Victoria. A water balance may vary significantly from council to council due to regional differences in rainfall, land uses and other physical characteristics. The vision statements of the City Councils of Kingston, Brisbane, and Knox include water balance as part of the development of a Water Cycle Strategy, including rain gardens and rainwater tanks.
The Canberra Times report on positive steps to solve Canberra’s water quality include the use of permeable pavements, rain gardens, and wetlands. An installation of a rain garden as small as 10 square metres will reduce the amount of stormwater from approximately 83,000 litres per year to around 15,000 litres per year, an 81% reduction.
With soft landscaping, bio-retention tree pits, and a rain garden, you can meet your city council’s requirements for a green water system.
StoneSet provides a hard-wearing, usable surface while being classified as “soft landscaping,” the best of both worlds.
Ref: Developing a Strategic Approach to WSUD Implementation, Guidelines for Councils, Melbourne Water