Document Type : Research Paper


1 2Professor, Department of Watershed Management Engineering, Faculty of Natural Resources, Tarbiat Modares University

2 epartment of Watershed Management, Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University


Today, the use of surface water to meet various human requirements such as drinking, agriculture and industry has endangered the health of this river ecosystem and its role in the natural system. The minimum environmental flow in the river provides a safe level of protection for the water-dependent environment. In the present study, the environmental flow requirement of three stations of Cheshmeh Langan River located in Isfahan province were calculated by two hydraulic methods: slope and maximum curvature of wetted perimeter. The results showed that both slope and curvature methods estimate the same minimum environmental flow requirement. So that the difference between the two methods in S1 station was about 0.07m3/s. According to the discharge measured at station S1, minimum environmental flow requirement is provided in all months except December. While the measured discharge at S2 and S4 stations cannot provide the minimum environmental flow requirement due to the impact of the dam and water transfer in any of the months. The flow of 0.39 m3/s for the first station (S1) and 1.44 an 1.68 m3/s for the second and third stations, respectively has been proposed as the minimum environmental flow requirement of Cheshmeh Langan River. The results of this study showed that the environmental flow requirement can be estimated using hydraulic method in data scarce.


[1] Abbaspour, K. C., Vaghefi, S. A., & Srinivasan, R. (2018). A guideline for successful calibration and uncertainty analysis for soil and water assessment: a review of papers from the 2016 international SWAT conference.
[2] Abdi, R., and Yasi, M. (2015). Evaluation of Environmental Flow Requirements Using Eco-Hydrologic-Hydraulic Methods in Perennial Rivers. Water Science and Technology, 72(3), 354–63.
[3] Amin, M., and Shokoohi, A. (2014). An Analytical Solution for Finding the Deflection Point of the Wetted Perimeter – Discharge Curve by Hydraulic Methods for the Determination of Environmental Flow Requirements. Journal of Hydraulics, 9(1), 27-43.
[4] Arcement, G. and Schneider, V. (1989). Guide for Selecting Manning’s Roughness Coefficients for Natural Channels and Floodplains, United States Geological Survey Water Supply Paper 2339.
[5] Arthington, A. H., Bhaduri, A., Bunn, S. E., Jackson, S. E., Tharme, R. E., Tickner, D., Young, B., Acreman, M., Baker, N., Capon, S., Horne, A. C.,  Kendy, E., McClain, M. E. , Poff, N. L., Richter, B. D. and Ward, S. (2018). The Brisbane Declaration and Global Action Agenda on Environmental Flows . Frontiers in Environmental Science, 6(45), 1–15.
[6] Arnold, J. G., Srinivasan, R., Muttiah, R. S., and Williams, J. R. (1998). Large area hydrologic modeling and assessment part I: model development 1. Journal of the American Water Resources Association, 34(1), 73-89.
[7] Azrakani, M., Shokoohi, A., and Singh, V. (2017). Introducing a Holistic Ecological Model under Data Shortage for Determining Rivers’ Ecological Water Requirements. Iran-Water Resources Research, 13(2), 140-153.
[8] Behmanesh, J., Mostafavi, S., and Zamanzad Ghavidel, S. (2017). Use of Soft Calculations at Estimation and Prediction of Environmental Flow Discharge (Case Study: Khorkhoreh Chay River). Journal of Civil and Environmental Engineering, 47.3(88), 9-22. (In Persian)
[9] Dastourani, M.T., and Sharifi darani, H., (2011). Efficient water currency    methods for   estimating runoff height in areas without statistics.   In the Fourth Fashion Conference of the Rhron Water Resources.
‎[10] Dabiri, F., and Kiani, M. (2008). Review of preventive laws and regulations, including environmental impact assessment in Iran and several industrialized countries. Environmental Science and Technology, 9 (4), 95-109. (In Persian)
[11] Dehghanzadeh, M., Mosaedi, A., and Farashi, A., (2017). Environmental flow assessment using wetted perimeter method. Second Conference on Science, Engineering and Environmental Technology, University of Tehran, Faculty of Environment, University of Tehran.  (In Persian)
[12]Esfandyari Darabad, F., Mostafazadeh, R., Shahmoradi, R., Nasiri Khiavi, A. (2019). Investigation the Effect of Boukan Dam on Hydrological Indices of Zarrineh River Based on Flow Duration Curve. Water and Soil Science, 29(4), 147-159. (In Persian)
[13] Esmaili Sari, A. (2019). Determining the Environmental Water Requirement in the Cheshmeh Langan River using Ecological, Hydraulic, Hydrological and Habitat Simulation Methods. Iran Water and Power Resources Development Company.
[14]Gassman, P. W., Reyes, M. R., Green, C. H., & Arnold, J. G. (2007). The soil and water assessment tool: historical development, applications, and future research directions. Transactions of the ASABE, 50(4), 1211-1250.
[15] Gain, A. and Giupponi, C., (2014). Impact of the Farakka Dam on thresholds of the hydrologic flow regime in the Lower Ganges River Basin (Bangladesh). Water, 6(8), pp.2501-2518.
[16] Gippel, C.J., and Stewardson, M.J. (1998). Use of wetted perimeter in defining minimum environmental flows. Journal of Regulated Rivers: Research and Management, 14, 53-67.
[17] Goodman, A.W. (1980). Analytical Geometry and the Calculus, 4th (ed.), Macmillan Publishing Co. Inc., New York, 997pp.
[18] Hosseinpour, D., Zare Bidaki, R., and Karimian Kakolaki, R. (2019). Use of the hydraulic method to estimate the minimum environmental flow for a part of Duab Samsami River. Journal of Natural Environment, 72(1), 59-72
[19] Jabbarian Amiri, B., and Kharazi Baheri, B. (2018). Comparing three approaches to determine environmental flow for Harou river in Ardabil province. Journal of Natural Environment, 71(2), 139-150.
[20] King, J. M., and Brown, C. (2018). Environmental Flow Assessments Are Not Realizing Their Potential as an Aid to Basin Planning, Frontiers in Environmental Science, 6, 133.
[21] Krysanova, V. and Arnold, J. G. (2008). Advances in Ecohydrological modelling with SWAT—a review. Hydrological Sciences Journal, 53(5), 939-947.
[22] Książek, L., Woś, A., Florek, J., Wyrębek, M., Młyński, D., and Wałęga, A. (2019). Combined Use of the Hydraulic and Hydrological Methods to Calculate the Environmental Flow: Wisloka River, Poland: Case Study. Environmental Monitoring and Assessment, 191(4), 1-17.‏
[23] Khoroshi, S., Mostafazadeh, R., Ismail A, Raouf, M. (2017). Evaluation of temporal and spatial changes of river hydrological health index in watersheds of Ardabil province. Iranian Journal of Eco-hydrology, 4 (2): 379-393. (In Persian)
[24] Liu, J., Liu, Q., and Yang, H. (2016). Assessing Water Scarcity by Simultaneously Considering Environmental Flow Requirements, Water Quantity, and Water Quality. Ecological Indicators, 60,434–41.
[25] Mosaedi, A. (2018). Evaluation of environmental water requirements by using hydraulic methods of wetted perimeter in Zarin Gol River, Iran. Journal of Environmental Science and Technology.  (In Persian)
[26] Nasiri Khiavi A, Mostafazadeh R, Esmali A, Ghafarzadeh O, Golshan M. Changes in Environmental Flow Components under the Effect of Sabalan Dam in the Qarehsou River of Ardebil Province . jwmr. 2019; 10 (19) :85-94(In Persian)
[27] Neitsch, S. L., Arnold, J. G., Kiniry, J. R., and Williams, J. R. (2011). Soil and water assessment tool theoretical documentation version 2009. Texas Water Resources Institute.
[28] Nikghalb, S., Shokoohi, A.R., Singh, V.P., and Yu, R. (2016). Ecological Regime versus Minimum Environmental Flow: Comparison of Results for a River in a Semi Mediterranean Region. Water Resources Management , 30(13), 4969–84.
[29] Noor, H., Vafakhah, M., Taheriyoun, M., and Moghadasi, M. (2014). Hydrology modelling in Taleghan mountainous watershed using SWAT. Journal of Water and Land Development, 20 (I–III), 11–18.
[30] Office of Engineering and Technical Criteria of Water and Water of Ministry of Energy (2011). Guidance on determining the water requirements of water stations no. 557, Deputy of Planning and Strategic Supervision of the President, 127p.
[31] Papadaki, C., Soulis, K., Ntoanidis, L., Zogaris, S., Dercas, N., and Dimitriou, E. (2017). Comparative Assessment of Environmental Flow Estimation Methods in a Mediterranean Mountain River. Environmental Management, 60(2), 280–92.
[32] Poorsalehan, S., Sedghiasl, M., and Parvizi, M. (2014). Application of The Wetted Perimeter Method for Predicting Minimum Environmental flow of Beshar River. Irrigation Sciences and Engineering, 37(1), 107-118.
[33] Prakasam, C., and R. Saravanan. (2021). Evaluation of Environmental Flow Requirement Using Wetted Perimeter Method and GIS Application for Impact Assessment. Ecological Indicators, 121, 107019.
[34] Raoof, M., Alioghli, S. (2020). Estimation of environmental flow of the Balikhlochai River and evaluation impact of Yamchi dam operation on hydrological and environmental regime of the river. Journal of Natural Environment, 73(2), 299-312.
[35] Revenga, C., Smakhtin, V., and Doll, P. (2004).Taking into account environmental water requirements in global-scale water resources assessments.  Comprehensive Assessment Research Report 2. Colombo, Sri Lanka: Comprehensive Assessment Secretariat.
[36] Richardson, B.A. (1986). Evaluation of instream flow methodologies for freshwater fish in New South Wales, In Campbell I.C. (eds.), Stream Protection, the Management of Rivers for Instream Uses. Water Studies Centre, Chisholm Institute of Technology, Caulfield, pp. 143–167.
[37] Shokoohi, A. R. (2015). Sensitivity Analysis of Hydraulic Methods Regarding Hydromorphologic Data Derivation Methods to Determine Environmental Water Requirements. Journal of Water and Wastewater, 26(3), 104-115. (In Persian)
[38] Shokoohi, A., and Hong, Y. (2011). Using hydrologic and hydraulically derived geometric parameters of perennial rivers to determine minimum water requirements of ecological habitats (case study: Mazandaran) Sea Basin-Iran). Hydrological Processes, 25, 3490-3498.
[39] Shokouhi, A., and Hang, Y. (2012). Use of Morphological Characteristics in Permanent Rivers to Determine Minimum Requirements for Ecological Aquatic Environment. Journal of Environmental Studies, 37(58), 117-128
[40] Sojka, M., Jaskuła, J., Wicher-Dysarz, J., and Dysarz, T., (2016). Assessment of dam construction impact on hydrological regime changes in Lowland River–A case of study: the Stare Miasto reservoir located on the Powa River. Journal of Water and Land Development, 30(1), pp.119-125.
[31] Suwal, N. et al. (2020). Optimisation of Cascade Reservoir Operation Considering Environmental Flows for Different Environmental Management Classes. Renewable Energy, 158, 453–64.
[42] Torabi Haghighi, A., Nasim Fazel, A., Hekmatzadeh, A. and Klöve, B. (2018). Analysis of Effective Environmental Flow Release Strategies for Lake Urmia Restoration. Water Resources Management, 32(11),3595–3609.
[43] Uday Kumar, A. and Jayakumar, K. V. (2021). Modelling of Environmental Flow Requirements Using Hydraulic and Habitation Models. Ecological Indicators, 121(October 2020),107046.
[44] Van Niekerk, L., Taljaard, S., Adams, J. B., Lamberth, S. J., Huizinga, P., Turpie, J. K., and Wooldridge, T. H. (2019). An Environmental Flow Determination Method for Integrating Multiple-Scale Ecohydrological and Complex Ecosystem Processes in Estuaries. Science of the Total Environment, 656, 482–94.
[45] Vatankhah, A. R. (2018). Normal Depth and Wetted Perimeter in General Power-Law Channels. Flow Measurement and Instrumentation, 64,234–41.
[46] Yasi, M. and Ashori, M. (2017). Environmental Flow Contributions from In-Basin Rivers and Dams for Saving Urmia Lake. Iranian Journal of Science and Technology - Transactions of Civil Engineering, 41(1), 55–64.
[47] Zhang, L., Buxian, Y., Xinan, Y., and Yanwei, Zh. (2019). The Influence of Channel Morphological Changes on Environmental Flow Requirements in Urban Rivers. Water (Switzerland), 11(9), 1–13.
[48] Zuo, Q., and Liang, S. (2015). Effects of dams on river flow regime based on IHA/RVA. Proceedings of the International Association of Hydrological Sciences, 368, 275-280.