Water quality simulation under river restoration measures for the Delhi stretch of river Yamuna, India

It is currently unclear how river restoration based on hydro-geometrical modifications, dredging, and creating a barrier instead of its removal on a river would affect the water quality in urban rivers. This work attempts to fill this gap in our understanding by simulating the water quality of a highly critical 22-km-long Delhi stretch of river Yamuna in terms of DO, BOD, and total coliform after the implementation of these river restoration measures. Four scenarios were conceptualized based on these restoration measures and water quality simulated. These are: scenario I: simulate the impact of varying the width uniformly for all reaches of the study stretch on the water quality, scenario II: simulate the impact of increased depth by controlled dredging. Scenario III (a) closing the ITO barrage gate and then simulating river water quality from Wazirabad barrage to ITO barrage and (b) closing the ITO barrage and simulation of water quality from ITO barrage to Okhla barrage. Results reveal that the water quality improved significantly in scenario I and scenario II. Scenario III did not yield desirable results in terms of water quality improvement. To the best of the author's knowledge, this is the first attempt involving river morphometry changes using the QUAL2k model for the Delhi stretch of river Yamuna.

Automated summary

This study simulates the water quality of river Yamuna in Delhi after implementing different restoration measures. The results show that changing the width and depth of the river significantly improves water quality. However, closing the barrage does not lead to desirable results in terms of water quality improvement.