Water quality of the heirok-wangjing river

The Physico-chemical and biological analysis of the Heirok-Wangjing River water was carried out over a stretch of 22.5km. Temperature, transparency, pH, dissolved oxygen, bio-chemical oxygen demand, carbon-dioxide, chloride, total alkalinity, acidity, calcium hardness, NO¬2 and NO3 etc. increased slightly from its origin to the end of the river in the valley. This increase in the parameters was the result of human activities. A total of fifteen species of fish and seven groups of aquatic insects and one class of annelids were recorded from the river.