Storm water management is a major issue today which many metropolitan areas are facing. The number of water catastrophes in the US due to flooding is one of the highest as compared to other disasters. So what is it that causes cities to flood? The concretization of cities is the major culprit that causes flooding. The concrete surface is impervious which does allow water to infiltrate into the soil like would generally happen in a natural environment. This increases the speed of runoff water as well which can be extremely dangerous when almost every time it combines with debris. Runoff water is high of pollutants as it washes off farms, streets, industries etc. Pathogens in this contaminated water have been well known to cause epidemic. Apart from this, most of the stormwater system in the US is Combined Sewer Outflow which highly pollutes the water bodies. It is clear from all the stated facts that it is essential for cities to come up with effective stormwater management practices.
Cities have been largely investing in Grey Infrastructure to curb stormwater runoff. Grey infrastructure has its limitations as it cannot effectively deal with stormwater beyond a certain threshold. When the Grey Infrastructure has reached its limit, water bypasses the water treatment plants and directly enters streams and rivers causing pollution. The solution to this might seem like a further investment in Grey Infrastructure but that too will have its shortcomings and will only end up increasing taxes on the people. The most effective solution to this would be to invest in Green Infrastructure. Green infrastructure largely mimics nature and effectively deals with stormwater from reducing pollutants to deceasing the runoff speed.
Green infrastructure includes bio swales, rain gardens, Infiltration trenches, rain barrels, permeable pavement etc. This have been proven to be very effective in terms of dealing with stormwater. Elmer Street in Sunny Valley, Los Angeles stands as a good example. Bio swales and rain gardens use native plant species which require less maintenance and are draught resistant. The water entering the bio swale and rain garden allow water to pass through it and filter pollutants and also reduce the speed of surface runoff. When the Bio Swale and rain garden fills up, water simply flows to the next bio swale through overflow pipes or outlets. Rain gardens work on a similar principal. All homes can be reworked with downspout that can lead to rain barrels instead of runoff. The rain barrels can be kept next to the rain garden so that when overflow happens the water infiltrates into rain gardens and bio swales.
Green Infrastructure at first might seem pricy but it is efficient considering long term use and also performance. Almost around 700 hundred cities built during the industrial era have combined sewer outflows which need to be replaced with green infrastructure instead of grey infrastructure to help mitigate the problem of storm water effectively and in a sustainable way.