URBAN STORMWATER DRAINAGE MANAGEMENT BY LOW IMPACT DEVELOPMENTS PRACTICES

Nowadays, climate change represents one of the greatest challenges to face in the management of the urban water systems. This problem is particularly crucial in the least developed countries of the world, where an uncontrolled expansion of the cities and of the human activities is often observed.
Recent studies about climate change indicate a growing frequency and intensity of extreme events, causing significant impacts and being one of the most serious challenges faced by society in coping with a changing climate [1] [2] [3] [4].
Extreme local precipitations now often exceed the values of design storms used for planning of the urban drainage systems and surface hydraulic structures in towns, causing the overflow of domestic drainage, urban storm water systems and small urban rivers, triggering flooding in urban areas [5] [6].
At the same time, the effects of development and urbanization practices on the hydrologic cycle are well known. Urbanization is typically accompanied by increases in impervious surfaces (rooftops, driveways, roadways, parking lots and sidewalks), compaction of soils, and modifications to vegetation (Fig. 1) [7]. This results in increased surface runoff, increased runoff velocity and stream erosion, decreased time of concentration of watersheds, and decreased water quality, due to water contamination in particular from suspended sediments, heavy metals, hydrocarbons, nutrients, and pathogens [8] [9] [10] [11].
In this regard, new strategies should be developed in order to mitigate the social and environmental impacts caused by the climate change and human modification on urban areas. In the context of urban water management, a predominant role can be played by innovative approaches, implementing optimization techniques and new technologies for Low Impact Development (LID) type of storm water Best Management Practices (BMPs) for urban runoff control [11]. The main goal of these strategies should be the improvement of the resilience of the cities against the increase of the storm water flows and the risk of flooding (urban flash floods), which could be responsible of significant impacts on the present and future urban and social development.