The Low Flow Assessment of Padma River in Bangladesh

  • Md. Abu Sayed Postgraduate student, Department of Civil Engineering, Chittagong University of Engineering & Technology (CUET), Chittagong 4349, BANGLADESH and Water Supply and Sewerage Engineer, Climate Resilient Infrastructure Mainstreaming Project, LGED.
  • Aysha Akter Chittagong University of Engineering & Technology (CUET), BANGLADESH
Keywords: Environmental Flow, HEC-RAS, Log-Pearson Type-III, Hilsha Breeding, Return Period


Low flow or Environmental Flow (EF) assessment is vital to ensure the river and ecosystem remain healthy. Both natural and human interventions might alter a river. Therefore, this study presents EF requirements of the famous Hilsa breeding center in the Padma River, Bangladesh, by applying the Hydrologic Engineering Centers River Analysis System (HEC-RAS) for discharge and water surface levels simulations at different stations. The frequency analysis of 20 years of historical data, spanning 2000-2019, used the Log-Pearson Type III (LP-III) distribution method, while the one-dimensional unsteady flow simulation was performed for the last 10 years (i.e., 2012-2019). Subsequently, the HEC-RAS simulated water level values reasonably correlated with the field observations at four stations, namely Baruria Transit, Mawa, Tarpasha, Sureswar, with Coefficient of determination R2=0.86, 0.83, 0.92, and 0.74, alongside simulated minimum water surface levels of 1.57 m, 0.37 m, 0.30 m, and 0.27 m, respectively. Also, the Baruria Transit and Mawa had simulated flows that reasonably correlated with the field observations at R2=0.70 and 0.61, with a simulated minimum flow of 3849.51 m3/s and 3789.14 m3/s, respectively. The minimum flow according to the frequency analysis was 4017 m3/s, 3685 m3/s, 3449 m3/s, 3229 m3/s, and 3113 m3/s at Baruria Transit and 3304 m3/s, 2781 m3/s, 2438 m3/s, 2141 m3/s, 1992 m3/s at Mawa station in 5, 10, 20, 50 and 100 years return periods, respectively. This study overlooked to report the ongoing investigations into the water quality issues. Thus, this study is expected to guide the required EF quantity towards a healthy Hilsha fish habitat and surface water source for drinking purposes in this studied river. The stated method is also applicable to other similar rivers around the world.


Abramowitz, M. and Stegun, I.A., 1965. Handbook of mathematical functions. New York: Dover.

Ahsan, D.A., Naser, M.N., Bhaumik, U., Hazra, S. and Bhattacharya, S.B., 2014. Migration, Spawning Patterns and Conservation of Hilsa Shad (Tenualosa ilisha) in Bangladesh and India.

Akter, A. and Ali, M.H., 2012. Environmental flow requirements assessment in the Halda River, Bangladesh. Hydrological Sciences Journal.

Akter, A. and Tanim, A.H., 2018. A modeling approach to establish environmental flow threshold in ungauged semidiurnal tidal river. Journal of Hydrology, [online] 558, pp.442–459. Available at: <>.

Akter, J., 2010. Environmental flow assessment for the Ganges river. (March), p.158.

Arthington, A.H. and Zalucki, J.M., 1998. Comparative evaluation of environmental flow assessment techniques: Review of methods. LWRRDC Occasional Paper Series 27/98.

Baten, M.A. and Titumir, R.A.M., 2016. Environmental challenges of trans-boundary water resources management: the case of Bangladesh. Sustainable Water Resources Management, 2(1), pp.13–27.

Brunner, G.W. and CEIWR-HEC, 2016. HEC-RAS River Analysis System User’s Manual. US Army Corps of Engineers–Hydrologic Engineering Center. [online] (January), pp.1–790. Available at: < 5.0 Users Manual.pdf>.

Editor Engr Taqsem Khan, C.A., Editor, E. and Shahid Uddin Director, A., 2019. DEWASA Annual Report 2018-19.

Ferdows, M., and Hossain, M, 2005. Flood frequency analysis at different rivers in Bangladesh: a comparison study on probability distribution functions. Thammasat International Journal of Science and Technology, 10 (3), pp.53–62.

Islam, N., 2006. IRLP or the Ecological Approach to Rivers? Economic and Political Weekly, [online] 41(17), pp.1693–1702. Available at: <>.

Jahid, S.A., 2016. Assessing Environmental Flow for the Kobadak River and Developing a Framework for Its Maintenance Assessing Environmental Flow for the Kobadak River and Developing a Framework for Its Maintenance. (February).

Kite, G.W., 1977. Frequency and risk analysis in hydrology. Fort Collins, CO: Water Resources Publications.

Moly, S.H., Rahman, M.A.T.M. and Saadat, A.H.M., 2015. Environmental Flow Characteristics of the Gorai River, Bangladesh. International Journal of Scientific Research in Environmental Sciences.

Mullick, M., Babel, M. and Perret, S., 2010. Flow characteristics and environmental flow requirements for the Teesta River, Bangladesh. Proceedings of International Conference on …, [online] pp.105–114. Available at: <>.

Neill, C., Hotopp, D. and Hunter, B., 2013. Some hydrotechnical features of Padma River, Bangladesh. pp.1–11.

Pusey, B.J. and Arthington, A.H., 1991. The utility and applicability of the in-stream flow incremental methodology (IFIM) for Australian lotic environments. SIL Proceedings, 1922-2010.

Pusey, B.J., Arthington, A.H. and Read, M.G., 1993. Spatial and temporal variation in fish assemblage structure in the Mary River, south-eastern Queensland: the influence of habitat structure. Environmental Biology of Fishes.

Rahman, A., Roy C., Rahman, A., Jamil, F., and Islam, M.S., 2019. Environmental Flow Assessment for the Main Rivers of the North-West Zone of Bangladesh. North American Academic Research, 2 (3), pp 81-101

Rahman, M.A.T.M.T., Moly, S.H. and Saadat, A.H.M., 2013. Environmental Flow Requirement and Comparative Study of the Turag River, Bangladesh. International Journal of Scientific Research in Environmental Sciences.

Rahman, M.K., Akhter, J.N., Nima, A., Ahmed, S.U. and Mazid, M.A., 2003. Studies on geo-morphology, ecology and fish production of the 92 rivers of Rajshahi Division , Bangladesh. Bangladesh ]. Fish. Res., 7(2), pp.141–150.

Saha, P.P., 2007. As assesssment of instream flow requirement of Gorai river considering salinity intrusion and fish habitat.

Smakhtin, V., Revenga, C. and Döll, P., 2004. Taking into Account Environmental Water Requirements in Global-scale Water Resources Assessments. Comprehensive Asessment of Water Management in Agriculture Research Report 2. IWMI, Colombo, Sri Lanka. Assessment.


Sunny, A.R., Ahamed, G.S., Mithun, M.H., Islam, M.A., Das, B., Rahman, A., Rahman, T., Hasan, N. and Chowdhury, M.A., 2003. Livelihood Status of the Hilsa ( Tenualosa ilisha ) Fishers : The Case of Coastal Fishing Community of the Padma River , Bangladesh. Journal of Coastal Zone Management, 22(2), p.469.

Tharme, R.E., 2003. A global perspective on environmental flow assessment: Emerging trends in the development and application of environmental flow methodologies for rivers. River Research and Applications.

USGS, 2019. Guidelines for Determining Flood Flow Frequency Bulletin 17C Book 4, Hydrologic Analysis and Interpretation. [online] Book:, Available at: <>.

How to Cite
Md. Abu Sayed, & Akter, A. (2021). The Low Flow Assessment of Padma River in Bangladesh. Journal of the Civil Engineering Forum, 8(1), 11-20.