Strengthening Urban Resilience to Flooding in Yangon using Sustainable Urban Drainage Systems

Abstract

The paper assesses the potential for adopting Sustainable Urban Drainage Systems (SUDS) in Myanmar to mitigate flood risks related to urbanisation. Fieldwork in commercial and industrial developments and informal settlements was undertaken to identify flood problems, understand causes and assess the potential for SUDS in Yangon. Hydrological modelling was used to assess the benefits in terms of flood risk mitigation from a quantitative perspective and engagement with key stakeholders facilitated a consideration of the practical implications of SUDS adoption. The results demonstrate that on-site source control technologies can play a key role in mitigating flood risks for storm events with return frequencies of 1 in 10-years. Based upon simulation results, whereas the existing situation shows extensive flooding with 45% of the area flooding to a depth of 0.25m, the SUDS scenario reduces this by 30% to 15% of the modelled catchment area. SUDS need to be adopted at scale for the benefits to be realised but the adoption of SUDS in existing developments is seen to be constrained due to practical and financial considerations. Therefore, green field sites offer the greatest potential for SUDS and a three-stage procedure based on flood risk and drainage impact assessments was developed to be incorporated in the existing planning applications process.