Optimisation of Water Sensitive Urban Design Practices using Evolutionary Algorithms

摘要

Population growth and urban consolidation have resulted in a movement away from the natural landscape, creating a greater proportion of impervious area, and an increase in urban stormwater runoff. The increase in stormwater runoff has typically been handled using traditional drainage infrastructure such as pipes, pits and detention basins. An alternative is Water Sensitive Urban Design (WSUD), which has been shown to counteract the effects of increased runoff by decreasing the proportion of impervious area and utilising natural retention/detention. This research utilised evolutionary algorithms as a means of identifying, at the lot scale, the most efficient combinations of WSUD practices (rain gardens, bio-retention cells, rainwater tanks, etc.) to meet designated hydrologic objectives at the catchment scale. Furthermore, an optimisation step was included to determine, and explore, the trade-offs between WSUD practices and traditional drainage infrastructure. A case study on the proposed South Campus Research Park at the University of Illinois Urbana Champaign (UIUC) was selected to determine the optimal combination of traditional and WSUD infrastructure to meet flooding, freeboard and peak flow criteria at minimum cost. The optimisation results showed that for a variety of rainfall Average Recurrence Intervals (ARIs) it is cheaper to use a combination of traditional drainage infrastructure and WSUD than to only use the traditional drainage infrastructure.