Water Pollution Load Assessment of Yamuna River Basin (Okhla -Agra)

Abstract

The current rate of depletion of fresh water resources are poses a threat to our future life support system. In order to maintain the status of our natural aquatic resources, sustainability is the main focus of an Integrated Water Resources Management (IWRM). Sustainable development will secure the availability of resources for further generations. On the downstream side of the Okhla barrage, Yamuna river has almost dried up, due to the abstraction of all the fresh water. The river on the downstream of Okhla Barrage has turned completely dark and dirty, and not fit to support any aquatic life. The present study was conducted to determine the amount of water pollution load caused by various human activities, which makes the Yamuna River dirtier day by day. The flow of the Yamuna River varies significantly during monsoon and non-monsoon seasons. The river constitutes maximum flow i.e. around 80% of the total annual flow during monsoon period. During non-monsoon period the Yamuna cannot be designated as a continuous river but segregated into four independent segments due to the presence of three barrages from where almost the entire water is being diverted for various human activities. The sources contributing pollution are both point & non-point type. Urban agglomeration at Faridabad, Vrindavan, Mathura and Agra is the major contributor of pollution in the Yamuna River. About 85% of the total pollution in the river is contributed by domestic sources. The condition of river deteriorates further due to abstraction of significant amount of river water, leaving almost no fresh water in the river, which is essential to maintain the assimilation capacity of the river. About 280 km long river stretch between Okhla barrage and Taj Mahal in Agra confluence is critically polluted. This stretch is characterized by high organic contents, high nutrients, significant depletion or increase in dissolved oxygen, severe odours etc. In the stretch from Okhla to Agra water quality monitoring was carried out to evaluate the pollution load of the river. Water quality monitoring facilitates evaluation of nature and 2 extent of pollution and effectiveness of pollution control measures, water quality trends and prioritization of pollution control efforts. Water samples were collected from the different river and drain location and pH, COD, DO, BOD, TSS and heavy metals were measured as per the APHA-AWWA standards. As the water quality standards are not remain same all over the stretch of the river. Therefore, it necessary to determine or have knowledge of the water quality of river before it enters the study area. Water quality of the Yamuna also studied thoroughly in the stretch starting from downstream of Hathnikund barrage to upstream of Okhla barrage to determine the fluctuation in the various parameters of river Yamuna. Variation in the water quality up to Okhla barrage is covered in chapter 4. From the Okhla barrage 101 cusec of water enters downstream of barrage, this is lesser than the minimum flow required for maintaining the sufficient flow in the river. Water samples collected from the downstream of the barrage even doesn’t meet the water quality criteria of class “C” of river water. Water samples also collected from the all the STPs, drains and river locations in the study area. Water quality status of the study area covered in chapter 5 and results obtained from the analysis of various physio-chemical parameters and heavy metals are detailed in chapter 6. Heavy metals were studied in the stretch between Okhla to Agra. Cadmium, Nickel and Lead were rarely present in the river, whereas zinc and iron were generally present. BOD was found exceeding the standards at almost every sample and DO were found nil in the stretch up to Agra. For abatement of domestic source of pollution in Yamuna river various steps are required to be undertaken, which includes – reduction of gap between wastewater generation and its treatment; maximum utilization of sewage treatment facilities; decentralization of sewage treatment plants; segregation of industrial and domestic waste; the treated sewage must be used for irrigation; aqua culture etc. To control industrial pollution, careful planning for the development of industrial areas based on environmental impact assessment is necessary. All the small scale industries should be connected with Combined Effluent Treatment Plant.