Water is a life sustaining source that has been an integral part of the human settlements from times immemorial. Through the evolution of settlements we have used water as a resource in various ways.
Storm water and Rain are a rich source of pure water when compared to rivers, streams and other ground sources, which for a major part have been polluted by human interventions. Harnessing these water sources especially in today’s context of dealing with environmental degradation is important. In many old cities like Pittsburgh and New York, CSO’s or Combined Sewer Systems have seriously underutilized such an important resource as storm water by mixing it with wastewater, which have been in process of redesigning. It highly advantageous to use the surface storm water for various purposes like ground water recharge, irrigation and watering gardens etc.
So when we consider how to manage storm and flood water, the basic solutions would be to build flood control reservoirs and detention ponds, but they do have disadvantages due to the maximum capacity they are designed for. A better approach to these issues would be to address the issue of storm water management in a decentralized way on a daily basis rather than only when the calamity strikes. Various solutions for managing run off in a decentralized way are storing using rain barrels or cisterns and reusing, soil infiltration, evapotranspiration, use of permeable surfaces, bio swales, rain barrels/cisterns, constructed wetlands and rain gardens, infiltration strategies, rainwater harvesting etc. Large scale issues like problems downstream due to upstream runoffs should also be addressed with localized solutions upstream as well as downstream with BMP’s (Best Management Practices) in a decentralized way.
Another major issue is water resource management in extreme weather. For example, California suffers from alternating droughts and floods. So, water resource management efficiently during floods can impact the water availability during droughts with the help of various Storm water management techniques that recharge the groundwater.
Reference : The post is based on Lecture ‘Green Water Infrastructure (GWI)’ by Nizar Eldaher