Assesement of Surface Water Availability of Kathmandu Valley Using SWAT Model
The study used the Soil and Water Assessment Tool (SWAT) model to analyse the surface water availability in the Kathmandu Valley. The model was calibrated and validated at Khokana station of basin area 592 km2 for the period from 2000 to 2015. To test the model’s performance for smaller subbasins, it was validated at Sundarijal station of basin area 16 km2. The daily runoff simulation statistics indicated that the model’s performance was satisfactory and the model effectively captured the runoff trend for the entire basin and subbasin catchment areas. This study demonstrates that the model can be adopted for assessing stream flow within the basin by selecting appropriate parameter values. The calibrated and validated model was subsequently applied to determine the surface water availability in surrounding mountainous, forested regions less affected by urbanisation, by setting up the model at 66 watersheds. The results indicate that the upper reaches of the Bagmati River basin and its tributary, the Nakkhu River, possess substantial surface water resources that can be utilised to alleviate water stress in the valley.
Abbaspour, K.C., Vejdani, M. and S. Haghighat (2015). SWAT Calibration and Uncertainty Programs. Eawag: Swiss Federal Institute of Aquatic Science and Techology.
Abbaspour, K.C., Yang, J., Maximov, I., Siber, R., Bogner, K., Mieleitner, J., Zobrist, J. and R. Srinivasan (2007). Modelling hydrology and water quality in the prealpine/alpine Thur watershed using SWAT. Journal of Hydrology, 333(2-4): 413-430. https://doi.org/10.1016/j. jhydrol.2006.09.014
Altinbilek, D. (2002). The role of dams in development. Water Science and Technology, 45(8): 169-180. https:// doi.org/10.2166/wst.2002.0172
Arnold, J.G., Moriasi, D.N., Gassman, P.W., Abbaspour, K.C., White, M. J., Srinivasan, R., Santhi, C., Harmel, R.D., Griensven, A. van, Liew, MW.V., Kannan, N. and M.K. Jha (2012). SWAT: Model use, calibration, and validation. Transactions of the ASABE, 55(4): 1491-1508. https://doi. org/10.13031/2013.42256
Baker, T.J. and S.N. Miller (2013). Using the soil and water assessment tool (SWAT) to assess land use impact on water resources in an East African watershed. Journal of Hydrology, 486: 100-111. https://doi.org/10.1016/j. jhydrol.2013.01.041
Bal, M., Dandpat, A.K. and B. Naik (2021). Hydrological modeling with respect to impact of land-use and landcover change on the runoff dynamics in Budhabalanga river basing using ArcGIS and SWAT model. Remote Sensing Applications: Society and Environment, 23: 100527. https://doi.org/10.1016/j.rsase.2021.100527
Bera, S. and R. Maiti (2021). Assessment of water availability with SWAT model: A study on Ganga River. Journal of the Geological Society of India, 97(7): 781-788. https:// doi.org/10.1007/s12594-021-1760-9
Bhatta, B., Shrestha, S., Shrestha, P.K. and R. Talchabhadel (2019). Evaluation and application of a SWAT model to assess the climate change impact on the hydrology of the Himalayan River Basin. CATENA, 181: 104082. https:// doi.org/10.1016/j.catena.2019.104082
Devkota, N. and N.M. Shrestha (2021). Development of rainfall – runoff model for extreme storm events in the Bagmati River Basin, Nepal. Journal of Engineering Issues and Solutions, 1(1): 158-173. https://doi.org/10.3126/joeis. v1i1.36835
Gupta, H.V., Sorooshian, S. and P.O. Yapo (1999). Status of automatic calibration for hydrologic models: Comparison with multilevel expert calibration. Journal of Hydrologic Engineering, 4(2): 135-143. https://doi.org/10.1061/ (ASCE)1084-0699(1999)4:2(135)
Guug, S.S., Abdul-Ganiyu, S. and R.A. Kasei (2020). Application of SWAT hydrological model for assessing water availability at the Sherigu catchment of Ghana and Southern Burkina Faso. HydroResearch, 3: 124-133. https://doi.org/10.1016/j.hydres.2020.10.002
Jordan, S., Quinn, J., Zaniolo, M., Giuliani, M. and A. Castelletti (2022). Advancing reservoir operations modelling in SWAT to reduce socio-ecological tradeoffs. Environmental Modelling & Software, 157: 105527. https://doi.org/10.1016/j.envsoft.2022.105527
Kc, S., Shrestha, S., Ninsawat, S. and S. Chonwattana (2021). Predicting flood events in Kathmandu Metropolitan City under climate change and urbanisation. Journal of Environmental Management, 281: 111894. https://doi. org/10.1016/j.jenvman.2020.111894
KUKL (2019). Kathmandu Upatyaka Khanepani Limited Annual Report 2076. KUKL. http://kathmanduwater. org/wp-content/uploads/2021/03/Annual%20Report%20 2077.pdf
Lamichhane and Shakya (2019). Integrated assessment of climate change and land use change impacts on hydrology in the Kathmandu Valley watershed, Central Nepal. Water, 11(10): 2059. https://doi.org/10.3390/w11102059
Molden, D. (2020). Scarcity of water or scarcity of management? International Journal of Water Resources Development, 36(2-3): 258-268. https://doi.org/10.1080/0 7900627.2019.1676204
Moriasi, D.N., Arnold, J.G., Van Liew, M.W., Bingner, R.L., Harmel, R.D. and T.L. Veith, (2007). Model evaluation guidelines for systematic quantification of accuracy in watershed simulations. Transactions of the ASABE, 50(3): 885-900. https://doi.org/10.13031/2013.23153
Nazari-Sharabian, M., Taheriyoun, M. and M. Karakouzian (2020). Sensitivity analysis of the DEM resolution and effective parameters of runoff yield in the SWAT model: A case study. Journal of Water Supply: Research and Technology-Aqua, 69(1): 39-54. https://doi.org/10.2166/ aqua.2019.044
Neitsch, S.L., Arnold, J.G., Kiniry, J.R. and J.R. William (2005). Soil and Water Assessment Tool Theoretical Documentation Version 2005. Soil and Water Research Laboratory, Agricultural Research Service.
Pokhrel, M. and N.M. Shakya (2021). Assessment of future land use/cover change of Kathmandu Valley using two models of land change. IOE Graduate Conference, 10: 463-471.
Saade, J., Atieh, M., Ghanimeh, S. and G. Golmohammadi (2021). Modeling impact of climate change on surface water availability using SWAT model in a semi-arid basin: Case of El Kalb River, Lebanon. Hydrology, 8(3): 134. https://doi.org/10.3390/hydrology8030134
Sharma, A., Patel, P.L. and P.J. Sharma (2022). Influence of climate and land-use changes on the sensitivity of SWAT model parameters and water availability in a semi-arid river basin. CATENA, 215: 106298. https://doi. org/10.1016/j.catena.2022.106298
Thapa, B.R., Ishidaira, H., Bui, T.H. and N.M. Shakya (2016). Evaluation of water resources in mountainous region of Kathmandu Valley using high resolution satellite precipitation product. Journal of Japan Society of Civil Engineers, Ser. G (Environmental Research), 72(5): I_27-I_33. https://doi.org/10.2208/jscejer.72.I_27
Thapa, B.R., Ishidaira, H., Pandey, V.P. and N.M. Shakya (2017). A multi-model approach for analyzing water balance dynamics in Kathmandu Valley, Nepal. Journal of Hydrology: Regional Studies, 9: 149-162. https://doi. org/10.1016/j.ejrh.2016.12.080
Thavhana, M.P., Savage, M.J. and M.E. Moeletsi (2018). SWAT model uncertainty analysis, calibration and validation for runoff simulation in the Luvuvhu River catchment, South Africa. Physics and Chemistry of the Earth, Parts A/B/C, 105: 115-124. https://doi. org/10.1016/j.pce.2018.03.012
Udmale, P., Ishidaira, H., Thapa, B. and N. Shakya (2016). The status of domestic water demand: Supply deficit in the Kathmandu Valley, Nepal. Water, 8(5): 196. https:// doi.org/10.3390/w8050196
Winchell, M., Srinivasan, R. and M.D. Luzio (2008). ARCSWAT 2.1 Interface For SWAT2005 User’s Guide.