Optimization of Manning’s roughness coefficient using 1-dimensional hydrodynamic modelling in the perennial river system: A case of lower Narmada Basin, India

• Published in: Environmental monitoring and assessment 2024-08, Vol.196 (8), p.743, Article 743
• Main Authors: Bhargav, Anurag M., Suresh, R., Tiwari, Mukesh K., Trambadia, Nevil K., Chandra, Ravish, Nirala, Sanjay Kumar
• Format: Article
• Language: English
• Subjects: Agricultural engineering; Atmospheric Protection/Air Quality Control/Air Pollution; Civil engineering; Climate change; Coastal zone; Coastal zones; Conservation of Natural Resources - methods; Creeks & streams; Decision making; Dimensional analysis; Earth and Environmental Science; Ecology; Ecosystem; Ecotoxicology; Emergency communications systems; Environment; Environmental Management; Environmental Monitoring - methods; Environmental risk; Flood forecasting; Flood management; Flood predictions; Flood risk; Floodplains; Floods; Flow velocity; Hydraulic models; Hydrodynamic models; Hydrodynamics; Hydrology; India; Modelling; Models, Theoretical; Monitoring/Environmental Analysis; Natural resources; Optimization; Perennial streams; Resource allocation; Risk allocation; Risk management; River discharge; River management; River systems; Rivers; Rivers - chemistry; Roughness; Roughness coefficient; Stormwater management; Sustainability management; Water conservation; Water discharge; Water flow; Water levels; Water management; Water Movements; Water resources; Water shortages; Wind
• ISSN: 0167-6369; 1573-2959; 1573-2959
• DOI: 10.1007/s10661-024-12883-w

This research bears significant implications for river management, flood forecasting, and ecosystem preservation in the Lower Narmada Basin. A more precise estimation of Manning’s Roughness Coefficeint ( n ) will enhance the accuracy of hydraulic models and facilitate informed decision-making regarding flood risk management, water resource allocation, and environmental conservation efforts. Ultimately, this study aspires to contribute to the sustainable management of perennial river systems in India and beyond by offering a robust methodology for optimizing Manning’s n tailored to the complex hydrological dynamics of the Lower Narmada Basin. Through a synthesis of empirical evidence and computational modelling, it seeks to empower stakeholders with actionable insights toward preserving and enhancing these invaluable natural resources. Using the new HEC-RAS v 6.0, a one-dimensional hydrodynamic model was developed to predict overbank discharge at different points along the basin. The study analyzes water levels, stream discharges, and river stage, optimizing Manning’s n and required flood risk management. The model predicted a strong output agreement with R 2 , NSE, and RMSE for the 2020 event as 0.83, 0.81, and 0.36, respectively, with an optimum Manning’s n of 0.03. The lower Narmada Basin part near the coastal zone (validation point) appears inundated frequently. The paper aims to provide insights into optimizing Manning’s coefficient, which can ultimately lead to better water flow predictions and more efficient water management in the region.