Green Highway Development Features to Control Stormwater Runoff Pollution

Beside buildings, highways and roads construction interfere with Stormwater runoff (SWR). They have two main impacts. They generate more runoff and pollutantswhile they contribute to the increase in impervious surfaces in the watershed and intensify activities. Regarding the increase of impervious surfaces, United States Environmental Protection Agency [1] states that roads occupy one third to two third of the land portion of the city (mostly impervious surfaces). The resulting effects of the hydro modification are increased volume of the runoff, change in sediment loading. From undeveloped area to developed zone with 30 to 50% of road impervious surface, the storm runoff rate increases from an average of 10% to 30% of the rain fall [2]. Kansas Department of Health and Environment exhaustively listed water pollution indicators as ammonia, total suspended solids (TSS), biochemical oxygen demand (BOD) and chemical oxygen demand (COD), chlorophyll, dissolved solids, heavy metals, minerals, nitrates, pesticides, pH, phosphorus, temperature, and turbidity. Barrett et al. [3] state highway pollutants are from three categories: organic, inorganic and microbial pollutants.Inorganic Pollutants (most common heavy metals) and the group of nutrients (herbicides, pesticides)) are toxic in high concentration and tend to amass into the tissue of aquatic flora and fauna [4,5]. Coliform bacteria are ordinary microbial pollutants encountered in storm runoff. They are of meticulous interest due to their easy access into the runoff either through anthropogenic sources or illicitconnections to stormwater sewer system. Waterborne diseases originating from non-point sources (NPS) pollution are alleged to be more detrimental than sedimentation issues in developing countries [6]. Additionally, erosion and sedimentation process contribute to Stormwater runoff pollution. Sediment sources from roadways include road sanding, runoff from unpaved roads and areas where soil has been exposed during construction.Malaysia is a country with an objective of being a fully developed country by 2020. Among the objectives stated in Malaysian’s 10th Master Plan (2010-2020) increasing water resources pollution and providing quality water which is expected to grow over 70% of the total population[7]. Controlling water pollution, water resource management is a priority in Malaysia where more than 90% of water supply if from rivers and lakes [8]. As a matter of fact, highway/roads have been identified, and developed countries are moving forward in curbing highway-related water pollution through the establishment of highway assessment framework. The current study aimed to identify criteria and sub-criteria in Green Highway development towards controlling Stormwater runoff pollution in Malaysia.