Green Roofs for Stormwater Runoff Control

INTRODUCTION In the Wider Caribbean Region (WCR), improperly treated domestic wastewater can be a significant source of marine pollution and represents a threat to human health, sustainable development and marine resources. However, a tendency to the stagnation in the sanitation services is observed among many municipalities in the region as population's size and the economy are increased. Also, natural resources vital to economic growth are wasted or lost through misdirected urban policies and practices, and population overspill into areas less suitable for urban development, thus creating further pressure on these resources as urban sprawl increases, turning the town concerned into one large drain 1 . The environmental problems associated with uncontrolled urban development are particularly marked among the poorest urban sectors those with the worst housing and the most restricted access to public services. But the principal impact of unrestrained urban expansion is on the environment caused by pollution of inland and marine waters, exhaustion of water reserves, destruction of woodlands and fertile agricultural land, and encroachment on ecologically-productive territory (the ecological footprint). The severest effects are declining drinking water reserves and deteriorating housing quality, public health and sanitation services 2 . In WCR countries, an important sector of the population lives in coastal areas where sewerage systems are deficient and even absent in some cases and have illegal connections to the storm drains. The limited access to a basic sanitation by means of the domiciliary connection to a sewer system, low[1]cost household systems made up of septic tanks, dry latrine and with discharge of water, and to the simple pit latrine; as well as the shortage of sewage treatment plants in countries that have sewer systems causing risks to public health and the environment 3 . The pattern of sanitation cover in the region is extremely patchy in terms of its extent and treatment capabilities, reflecting sharp differences between the various countries in terms of culture and tradition, as well as degrees of socio-economic development; factors that significantly influence the lives of their populations and the environmental quality. The development of these services in the region over the last three decades compares quite favorably with other parts of the world. However, as regards to coverage, the absolute numbers are worrying, an estimated 100 million inhabitants (15% of those living in upstream coastal areas) have no access to sanitation services, while some 43% of the sewer system effluents receives some degree of treatment(pre-treatment, primary treatment, secondary treatment, tertiary treatment or sewage discharges by means of submarine outfalls) 4 .