ABSTRACT

Efficient drainage systems in urban areas were introduced for the safe passage of urban runoff to the downstream stream/water body. Since they involve huge capital costs, developed countries were obviously ahead in implementing infrastructures with proper planning and design. A critical design parameter is the design velocity along the channel, which needs to be satisfied considering potential damage of grass and/or channel surface. The hydraulic capacities and calculations for bioretention systems are the same as for sand filters, the only exception might be that, due to the presence of vegetation roots, the hydraulic conductivity value of the filter media is expected to be higher. The traditional practice of conveying higher volumes of stormwater was to provide a concrete-lined channel with the aim of swift drainage of generated runoff from upstream of a catchment to some downstream locations. Rainwater tanks have been in use for many centuries, especially for remote communities where other sources of water are scarce.