The Potential of Urban River Reserve in Modifying Outdoor Thermal Condition : A Case Study in Johor, Malaysia

Abstract

The urban riparian in Malaysia is also known as river reserve. Section 62 of the National Land Code 1965 has stipulated that the State Authority has the power to reserve state land for any public purposes, including river reserves. Nonetheless, its criteria are determined by the width of the reserved land and are highlighted only for bank stabilization, biodiversity, and water quality purposes. Additionally, some studies have proven that vegetated urban riparian promotes thermal reduction, in comparison to those covered with mere hard surfaces. As such, this study looked into the effect of urban riparian structure upon local thermal environment so as to gain an overview of the possible form of heat transfer occurrence. With that, this study investigated two varied formations of river reserve located side-by-side, which is bound by the same river in Johor, Malaysia. Despite of the low-albedo materials, the developed river reserve displayed somewhat lower air temperature, when compared to undeveloped river reserve area. In addition, ambient air temperature and relative humidity of both the investigated sites were linked to some factors, such as shading and wind movement. In fact, vegetation vertical clearance that caused wind flow obstruction could have been influential as well. Therefore, the effect of vegetation structure has to be comprehensively understood. With that, it is possible to determine the multiple functions of a river reserve, especially after implementing several passive cooling strategies within the area.