Biological Monitoring - a sustainable water management approach

The increasing demand for water, the large variety of water uses and also the direct use of the river catchments have partially impaired many rivers in such a way that they completely lost their natural functionality and thus can no longer provide their ecological services to mankind. Water in the Kathmandu Valley is derived from two sources: surface water (rivers and ponds) and groundwater. They are basically fed with rainfall. Rivers are important running surface water in terms of water volume and potential development. Over time, requirements for water for drinking and personal hygiene, agriculture, religious activities, industrial production, and recreational activities, such as swimming and fishing, have increased in the valley. Nevertheless, the rivers are also the main repository for the valley’s untreated sewage, solid waste, and industrial effluents. The biota of an aquatic ecosystem directly reflects the existing condition and the information available have been utilized very extensively in the biological monitoring of water pollution levels worldwide. Experience in Europe and elsewhere and recently adopted in HKH region clearly indicated that biological assessment methods appear to be appropriate based on benthic macroinvertebrates. This paper deals with the methodology to evaluate the ecological status of the streams in the HKH region and the case study of Bagmati River System, Kathmandu Valley.