Water quality and sediment characteristics of Batang Ai downstream of the dam compared to the reservoir

Construction of dam IS Important in controlling massive water flow from upstream to downstream but it also may cause ecological change to its surroundings. Hence, this study is about water quality and sediment characteristics of Batang Ai downstream of the dam compared to the reservoir. The study was conducted on 9 - 11110/2014 and 29/1 - 112/2015. When going further away from reservoir to the downstream, there was an increase in conductivity and turbidity but decrease in temperature, pH, dissolved oxygen, depth and transparency. The mean range for ex situ parameters were total suspended solids (1.3 57.7 mg/L), chlorophyll-a (1.0 - 4.6 mg/m'), biochemical oxygen demand (1.92 - 4.12 mgIL), chemical oxygen demand (45.3 - 88 02/L), total sulphide (0 - 0.07 mg/L), nitrite-nitrogen (0 - 0.012 mg/L), nitrate-nitrogen (0 - 0.18 mgfL), ammoniacal-nitrogen (0.09 - 2.69 mg/L), total nitrogen (2.81 - 8.99 mg/L), phosphate-phosphorus (0.02 - 0.12 mg/L) and total phosphorus (0.15 - 2.39 mgIL). Biochemical oxygen demand, total suspended solids, ammoniacal-nitrogen and chemical oxygen demand had exceeded Class II of Water Quality Index. For sediment characteristics, particle size analysis, moisture content, total organic carbon, organic matter, total phosphorus and total nitrogen had been analysed. Most of the higher reading came from station near residential area and plantation site