Restoring The Yamuna River Basin

River BasinUsing Integrated Water Resources Management and Water Quality Modelling

Millions of people in India depend on the Yamuna River for domestic, industrialand agricultural uses. During the non-monsoon (dry) season, however,stretches of the river become highly polluted and the water quality drops. Tohelp the Government of India (GoI) improve the water quality during the dryseason, we conducted an Integrated Water Resources Management (IWRM)and water quality modelling study. As part of the study, we also created a Decision Support System (DSS) that will enable authorities to restore the waterquality of the river based on sound information. PROTECTING A SACRED RIVER The 1,376 km long Yamuna River - the largest tributary of the Ganga River - is oneof the most important and sacred rivers in India. The Ganga's 360,220 km2basinarea spreads across seven states: Uttarakhand, Himachal Pradesh, Uttar Pradesh,Haryana, Delhi, Rajasthan and Madhya Pradesh. Approximately 12.4% India'spopulation depends on the Yamuna River basin. Over the years, the river has experienced severe degradationof its water quality, primarily caused by:

• rapidly changing land use
• over-exploitation of water resources for irrigation -approximately 90% of water resources are utilised for thissector.

Nearly all the water received at Hathnikund Barrageduring dry seasons is distributed to meet the irrigationrelated demands of Uttar Pradesh and Haryana as well asthe drinking water demands of Delhi

• domestic and industrial water use leading to low-flow or noflow conditions in the river
• discharge of untreated wastewater from growing urbancentres
• discharge of organic wastes from agriculture-basedindustries (including distilleries, sugar mills and paper mills)

The Yamuna River is in pristine condition and has a goodwater quality before it reaches the towns of Yamuna Nagar and Panipat, where it becomes highly polluted - mainly due tothe discharge of untreated sewage. In Delhi, the BiochemicalOxygen Demand (BOD) ranges from 6 to 35 mg/l - with verylow to zero Dissolved Oxygen (DO) and millions of coliformcounts - in the 22 km stretch between Wazirabad and OkhlaBarrage. Downstream of the Okhla Barrage, the river receives partiallytreated sewage from East Delhi. This is the only water flowinginto the river during the non-monsoon (dry) period, whichcauses increased pollution. Further downstream, the Yamunaalso receives pollution from Mathura and Agra. The riverremains polluted until it meets with the Chambal River, afterwhich the Yamuna regains its good quality due to dilution. Thelow-flow and no-flow conditions prevalent over a considerableportion of the river and its tributaries have seriously impacted the Yamuna. The discharge of domestic sewage, however, is the maincause of river's pollution. There is a large gap between the amount of wastewater generated and the amount ofwastewater treated in all the cities and urban centres throughout the basin. Increasing urbanisation is furtherwidening this gap. Treating sewage before it is discharged is not enough to restore the ecological integrity of the river. Anumber of options need to be considered to find a solution,including:

• using state-of-the-art technologies such as an interceptorsewer to treat sewage
• significantly reducing BOD in sewage before it is dischargedinto the river
• diverting treated sewage for agricultural purposes

HELPING TO RESTORE WATER QUALITY

To help water officials regain the good water quality of theYamuna River, we conducted an Integrated Water ResourcesManagement (IWRM) and water quality modelling study. Aspart of this study, we developed a Decision Support System(DSS) that uses baseline information on:

• topography
• land use
• river flow
• water quality
• wastewater discharges
• less water intensive crops

For this project, we used MIKE BASIN, MIKE 11 and ECO Lab(part of our MIKE by DHI software) to develop the DSS. Weused MIKE BASIN to describe the catchment's hydrology,examine abstractive uses (such as irrigation and domesticwater use) and their return flows, and estimate pollution load. We used MIKE 11 and ECO Lab to conduct riverhydrodynamic and water quality modelling. Our DSS integrates the mathematical models of systemprocesses with decision variables to arrive at certain conclusions or decisions.It can take into account differentwastewater loading and water availability situations - as wellas management options and future changes - to predict waterquality scenarios. Utilising the DSS, we generated waterquality scenarios based on different actions in order to:

• control wastewater discharges to the basin
• increase the availability of water resources in the basin byusing less water intensive crops

The scenarios will enable government planners to makesound decisions in order to help restore the quality of the Yamuna River and manage its pollution levels Source: DHI Group

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Taxonomy

• Environment
• River Basin management