Investigation of surface water quality and degree of hardness at Semenyih Dam, Selangor / Norfadzilah Abd Rahim

Semenyih Dam is one of the Klang Valley major dams in Malaysia which is an important water resource. Water quality is important because they help to protect and restore of the quality of surface water that is suitable for human use. The objectives of this study are to determine Water Quality Index (WQI), water classification and to measure the degree of water hardness for surface water at Semenyih Dam. Besides that to compare the obtained results with the standards set by Malaysian government for raw water quality. Water samples from four samplings were sampled from January to February 2008 and analyzed for physical and chemical parameters. The findings show that Water Quality Index (WQI) for four samplings are in Class II. Class II is means that the water is suitable for drinking water resource but needs general treatment. Water Quality Index (WQI) was calculated based on 6 parameters which were Dissolved Oxygen (DO), Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), pH, Total Suspended Solid (TSS) and Ammoniacal-Nitrogen. The average of total hardness for all sampling points was 25.44mg/L. This range indicates the degree of water hardness is soft.