Key issues for sustainable urban stormwater management.

Since ancient times, it is understood that stormwater from constructed areas should be managed somehow. Waste and pollution transported by stormwater poses quantity and quality problems, affecting public health and the quality of the environment. Sanitation infrastructures in urbanized regions have different development levels and the perception of stormwater changed considerably during the centuries and especially in recent years. Still, there is an evident worldwide heterogeneity when analyzing the lack of studies on urban stormwater conducted in some Asian or African countries. Strategies for sustainable stormwater management are needed at different decision levels (political, regional or local scale, for instance) but all of them need information and a clear understanding of the possibilities that are at stake as well as the main consequences of each decision. A sound approach to stormwater management should be flexible, based on local characteristics, and should take into consideration temporal, spatial and administrative factors and law, among other issues. Economic or technical constraints define different decision scenarios. Best Management Practices should be seen as an opportunity for development and improvement of social, educational and environmental conditions in urbanized and surrounding areas. Therefore they require an ample perspective and the participation of different stakeholders. High-quality decision needs time and a fair overview of the problem: the purpose of this document is to contribute to sustainable stormwater management, informing on the most relevant factors that should be assessed and their interaction. A flowchart has been produced and is presented, indicating the most relevant steps, processes and information that should be taken into account in urban development.