Review of Water and Heat Balances and Challenges to Adoption of Permeable Pavement System in Vietnam

Abstract

Permeable pavement system (PPS) contributes to mitigating urban floods and urban heat islands (UHI). PPS has been widely used in developed countries for low-traffic areas, parking lots, and sidewalks. However, PPS has not received much attention in developing countries such as Vietnam. Monitoring studies on PPS mostly focus on hydrological and thermal performance related to volume, rate of flow, and surface temperature, but studies of water and heat balances are somewhat limited. This study, therefore, summarizes hydrological and thermal performance especially focusing water and heat balance in PPS, and the measurement techniques/instruments to construct a suitable monitoring system for application to pavement. In addition, challenges to the adoption of PPS in Vietnam were also investigated, fully considering technical standards/requirements and case studies in developed countries. The results showed that PPS contributes to flooding control due to a large infiltration/drainage component. Water vapor carries away a portion of the energy that arrives at the pavement surface, resulting in a reduction in sensible heat and UHI. Evaporation has been the most difficult component to accurately quantify. A lysimeter system is commonly used to measure components of water balance but cannot be easily integrated into a full-scale PPS installation. A monitoring vault can be used in full-scale applications, but a suitable method is required to accurately determine evaporation. The challenges/requirements for PPS adoption in Vietnam include site-specific, technical/engineered, economic, environmentally friendly, associated facilities, current policies, and awareness.