This brief report by the Central Pollution Control Board (CPCB) presents an analysis of the monitoring of the water quality in India under the National Water Quality Monitoring Programme. The water quality data for the years 2002-2008 has been analysed and monitoring locations exceeding the water quality criteria have been identified as polluted locations with respect to risk.
The present monitoring network comprises of 1429 stations in 27 States and 6 Union Territories spread over the country. The monitoring network covers 293 Rivers (810 stations), 94 Lakes (102 stations), 9 Tanks, 41 Ponds, 15 Creeks/seawater, 23 Canals, 18 Drains and 411 Wells.
The identification of polluted river stretches is based on the risk. Risk here has been defined as – Risk = Frequency of violation of criteria X Consequence (Magnitude). The degree of violation is with respect to water quality criteria (specifically BOD) for drinking water source under conventional treatment. The polluted locations in a continuous sequence have been defined as polluted river stretches.
Priority | Definition of criteria | Number of Stretches |
Priority 1 | Locations with BOD > 30 mg/l in on any occasion; All monitoring locations with BOD > 6 mg/l on all occasions. | 35 |
Priority 2 | Monitoring locations having BOD between 20-30 mg/l on any occasion; All monitoring locations with BOD > 6 mg/l on all occasions. | 15 |
Priority 3 | Monitoring locations having BOD between 10-20 mg/l; All monitoring locations exceeding BOD concentration 6 mg/l on all occasions. | 26 |
Priority 4 | Monitoring locations having BOD between 6-10 mg/l. | 38 |
Priority 5 | Monitoring locations having BOD between 3-6 mg/l. The locations exceeding desired water quality of 3mg/l BOD. | 36 |
Total |
| 150 |
The report presents the approach to water quality management in the country. The Central Pollution Control Board (CPCB) has tried to define the wholesomeness in terms of protection of human uses, and thus, taken human uses of water as base of or identification of water quality objectives for different water bodies in the country.
It was considered ambitious to maintain or restore all natural water body at pristine level. Planning pollution control activities to attain such a goal is bound to be deterrent to developmental activities and cost prohibitive. Since the natural water bodies have to be used for various competing as well as conflicting demands, the objective is aimed at restoring and/or maintaining natural water bodies or their parts to such a quality as needed for their best uses.
Thus, a concept of “designated best use” (DBU) was developed. According to this concept, out of several uses a water body is put to, the use which demands highest quality of water is termed as “designated best use”, and accordingly the water body is designated. Primary water quality criteria for different uses have been identified.
The note presents the use based classification of surface waters in India. The entire water resources of the country were classified according to their designated best uses and a “Water Use Map” was prepared. For identification of the water bodies or their parts where water quality is at variance with water quality criteria, it was felt important to measure water quality of that water body or its part. It would help in preparation of “Water Quality Map” of India. The idea was to superimpose “Water Quality Map” on “Water Use Map” to identify the water bodies or their parts, which are in need of improvement (restoration).
Subsequently through a wide network of water quality monitoring, water quality data are acquired. A large number of water bodies were identified as polluted stretches for taking appropriate measures to restore their water quality. Today almost all policies and programmes on water quality management are based on this concept including the Ganga Action Plan and National River Action Plans.
Download the report here -
Polluted_river_stretches_in_India_Criteria_and_status_Central_Pollution_Control_Board_2011.pdf
