Sustainable surface water management and green infrastructure in UK urban catchment planning

Based on the analysis of impervious surface cover and water balance studies, it is argued that conventional, separately-sewered first-generation and alternative second-generation sustainable drainage systems (SUDS) cannot provide a fully sustainable surface water management approach for urban catchment planning. An extended approach based on the introduction of micro-and meso-vegetative SUDS systems into a wider green infrastructure (GI) framework is advocated to effectively address on-site and catchment urban surface water issues. The approach is based on the integrated planning implementation of street ‘greening’, with optimisation of existing biofiltration SUDS solutions, together with green roofs, downspout disconnection and sub-catchment riparian corridors to achieve a minimum 25--30% canopy cover level. A ‘leaf-out’ inventory procedure using GIS and satellite imagery can be employed to assess potential vegetative SUDS locations and types, and their likely impact upon the urban water cycle and receiving water health. However, there is a need to ensure that GI elements are incorporated into planning approaches and protocols for urban drainage infrastructure provision.