There is a water catchment area located along Sungai Layang sections near the Sultan Iskandar Reservoir. Senai–Desaru Expressway traverses through the environmentally sensitive water catchment area of Sultan Iskandar Reservoir. Senai–Desaru Expressway is the only expressway in Malaysia which features the Pollutant Removal System (PRS). The expressway took one step higher by introducing the PRS to monitor and control any potential impact to the water quality in Sultan Iskandar Reservoir in the event of a spillage of dangerous and hazardous chemicals from any vehicle travelling on the expressway.