Classifying Headland-Bay Beaches and Dynamic Coastal Stabilization

In this paper, a framework is developed for classifying bay types using stability and a sediment supply source. The framework is used to classify a total of 212 headland-bay beaches in Southeast Asia. The results show that static bays, bays with no sediment supply, and dynamic bays (with a sediment supply), account for 36% and 64%, respectively, while stable bays, bays that can maintain their long-term shoreline stability, and unstable bays (changing their shape over time), account for 69% and 31%, respectively. The results reveal the importance of dynamic bays. The dynamic parabolic bay shape and bay characteristic equations have been verified to bridge the knowledge gap of coastal stabilization and management in dynamic bays. The verification of bay characteristic equations shows an efficiency index of more than 78%. The bay characteristic equation shows that dynamic bays are highly sensitive to low sediment supply and become less sensitive when the sediment supply increases. Knowledge of the coastal stabilization concept successfully implemented for static unstable bays has been extended in this study and applied to stabilize dynamic unstable bays using the verified equations. Sediment control and the combined method are developed in this study, and a case study is presented on the stabilization of a dynamic unstable bay

Combining Ecosystem Services with Cost-Benefit Analysis for Selection of Green and Grey Infrastructure for Flood Protection in a Cultural Setting

The present paper describes a methodological framework that combines ecosystem services (flood protection, education, art/culture, recreation and tourism) with economic analysis for selection of multifunctional measures for flood resilience. The framework includes active stakeholder participation and it consists of the four main components: (1) identification and valuation of ecosystem services pertinent to the project site under various mitigation scenarios, including baseline (pre-mitigation conditions); (2) evaluation of most effective flood mitigation measures through hydrodynamic simulations, and evaluation of economic viability using cost-benefit analysis; (3) selection of measures through consideration of ecosystem services, and solicitation of stakeholders’ inputs; (4) development of the conceptual landscape design. Application of the framework was demonstrated in a case study of Ayutthaya Island, Thailand. Results of our research suggest that taking a holistic perspective of ecosystem services and economic assessments, marshalled through active stakeholder participation, has the potential to achieve more ecologically sustainable and socially acceptable solutions for flood protection in areas with cultural heritage. However, there is still a considerable challenge in taking this framework to a full-scale practical implementation, and this mainly relates to the selection of indicators that can enable proper application of ecosystem services

Exploratory Assessment of SUDS Feasibility in Nhieu Loc-Thi Nghe Basin, Ho Chi Minh City, Vietnam

Aims: In recent decades, Ho Chi Minh City, Vietnam, frequently has been affected by local floods and inundation from heavy rainfall. Conventional flood mitigation measures such as building flood gates and upgrading sewerage systems have been implemented but problems persist. The objective of this research is to assess another approach for flood control measures, namely Sustainable Urban Drainage Systems (SUDS), with application to the Nhieu Loc - Thi Nghe Basin, located in the central part of Ho Chi Minh City.Methodology: A combination of the Stormwater Management Model (PCSWMM) and interviews with 140 households was used to assess the efficacy and acceptability of four of the most popular SUDS: Rainwater harvesting, green roofs, urban green space and pervious pavement. Thirteen SUDS and urban build-out scenarios were simulated under 6 design storm conditions.Results: PCSWMM results showed that inundation from intense rainfall could be reduced with proper land-use control, specifically by maintaining imperviousness at 65% or less of the surface area. With respect to SUDS performance, green roofs were best at reducing peak runoff (22% reduction), followed by pervious pavement, urban green space, and rainwater harvesting systems. Regarding environmental improvements, as represented by reduction in total suspended solids load, urban green space was best with 20% of the solids load removed compared to the base case scenario, followed by green roofs, pervious pavement, and rainwater harvesting. The household interviews revealed the majority of people preferred pervious pavement to the other SUDS options and the least preferred option was green roof technology.Conclusion: Considering the combination of water quantity and water quality controls, it seems that green roof technology was the best performer for this area of Ho Chi Minh City, followed by urban green space, pervious pavement and rainwater harvesting. However, green roof technology also was the least favored option for the public and stakeholder acceptance will impact SUDS implementation