Construction activities contribute significantly to greenhouse gas emission. Along with the rapid urbanization we have seen our cities to be progressively built up. Our built environment has created negative impact toward our environment in many ways and in every step of the ways. Pollution, erosion and flooding are just a few upon many of our environmental problems. For many people, such problems are considered to be inevitable as a price of progress. However it doesn’t have to be that way, we can choose to reduce the negative impact of our built environment.
Managing our storm water is one important way to take care of our environment. Urban storm water runoff is a major contributor to water bodies’ pollution. Our built up environment has changed the way water flows. Natural pervious surfaces that allow rainwater to recharge are rapidly converted into impervious surfaces such as paved sidewalk, parking lots and driveways. Before reaching the city drain, rainwater run off pick up various pollutants from such surfaces. Pesticides, fertilizer, used oil, pets waste, litters, construction debris are just to name among many pollutants that can end up in the nearest body of water.
The importance of storm water management has been recognized in many cities in US and Europe. City authorities are working hard to raise awareness on the importance of good practice in storm water management and to encourage the city inhabitants to do their part to maintain the quality of their water bodies. The city of Durham in North Carolina even introduced a palpable storm water billing which sees its inhabitants paying a certain amount of utility fee that is calculated based on the quantity of impervious area on their land parcel such as rooftops, driveways, parking lots, paved surfaces. The idea is that every city inhabitants contribute to the addition of impervious surface thus inadvertently contributes the storm water problem. This amount of utility fee often referred as storm water dollars is used to fund many activities such as conducting preventive measure to curb further pollution (street sweeping, waste removal), maintenance of the public drainage system, assessment of water body, stream restoration program, running harzardous waste collection system, and public education.
In Asia, HDB (Housing Development Boards), Singapore’s government agency that deals with housing provision has recently published its new landscape guide aimed for architects and landscape designers who are involved in the physical planning of public housing. Some new concepts are incorporated in the guide such as vertical greenery, bio-diversity along with water sensitive urban design or WSUD approach. The adoption of WSUD is in line with government’s recently initiated program, Active Beautiful Clean Waters (ABC Waters) which promotes localized storm water management as landscape features to create a more sustainable water management and at the same time creating interesting water elements that can be enjoyed by the community.
In the guide, HDB proposes landscape soakaway, water retention basin, swale and vegetated swale, bioretention swale and bio retention basin as the preferred WSUD types that can be incorporated in the planning of housing estates. Those types are considered to be sustainable types considering Singapore’s land scarcity and ease of maintenance.
In the same line with the ABC Waters program, the building authority of Singapore, BCA, in their Green Mark guide for new residential projects recommends several ways to deal with storm water run-off. BCA listed infiltration features such as bio retention swales, rain gardens, constructed wetlands, cleansing biotopes and retention ponds as suggested storm water management. The adoption of any of such features can earn projects some points to satisfy green building requirements.
As city inhabitants there are many ways to do our part to participate in good storm water management practice for example by using less fertilizer, picking up after our pets and properly disposal of hazardous materials. Landed property owners can look into installing rain water harvesting tank as a part in the efforts to reduce rain water runoff.
Rain garden is one infiltration features that can be easily installed in the garden by property owners in their own backyards. Rain garden basically is a depression on the ground into which rainwater is channeled to be slowly absorbed by the ground. It is acting as pervious surface. The idea is to provide a catchment area for rainwater thus reducing the volume of storm water that flows to natural water bodies. Rain garden can be connected to rain water spout or simply located near walkways to catch its surface water.
All too often sustainable buildings are associated merely with energy performance and sustainable building materials selection. Whilst both factors are important, sustainable buildings concept should go beyond that. For example, good storm water management should be an integral part of sustainable building projects. We should start to include our gardens and backyards as potential tools in our efforts to build more responsibly.
By: Devisanthi Tunas