Abstract :
Water quality can be affected by various aspects of either natural or physical changes in the area. This article discusses the effects of water quantity and quality in the upper area of tropical river in Upper Dong natural forest reserved at Dong River, Raub Pahang, Malaysia. Data observations were made from 16 to 21 November 2009. Five sampling stations were selected along 2.4 km encompassed the upstream and downstream of the river. Overall, the water quality status as stated in INQWS is categorized as Class I. Statistical analyses show that water quality parameters were changed significantly along the river reach. Towards downstream, the water quality became more deteriorated followed by reduction on flow velocity. Statistical values for temperature and distance between station from upstream to downstream is R2= 0.989, R2 = 0.882 for TDS, R2= 0.946 for Conductivity and R2= 0.803 for Do (mg/l). Natural factors such as flow velocity, water quantity and land use changes (rubber tree agriculture) from natural forest to village landscape found causing an impact to water quality changes.
