Impact of Climate and Land Use Changes on the Flood Hazard of the Middle Brahmaputra Reach, India
Subashisa Dutta and Shyamal Ghosh
Department of Civil Engineering, Indian Institute of Technology Guwahati (IIT Guwahati), Guwahati-781039, Assam, India
Being the highest specific discharge river in the world, the Brahmaputra has a large floodplain area of 700 km in length in its middle reaches falling in the high flood vulnerability category. Floods generated in upland Himalayan catchments are mainly controlled by land use and land cover, storm characteristics, and vegetation dynamics. Floods propagate through a floodplain region consisting of wetlands, paddy agriculture, and wide braided river reaches with natural constraint points (nodals) that make the reaches more vulnerable to flood hazards. In this study, a macroscale distributed hydrological model was used to obtain the flood characteristics of the reaches. A hydrological model with spatially distributed input parameters and meteorological data was simulated at (1 km × 1 km) spatial grids to estimate flood hydrographs at the main river and itsmajor tributaries. Aftermodel validation, “best guess” land use change scenarios were used to estimate potential changes in flood characteristics. Results show that at the middle reaches of the Brahmaputra, peak discharge increases by a maximum of 9% for land use change scenarios. The same model with bias-corrected climatological data from a regional climate model (RCM) simulation (PRECIS) was used to obtain future changes in flood generation and its propagation through the basin in the projected climatological scenario. Changes in flood characteristics with reference to the baseline period show that the average duration of flood waves will increase from 15.2 days in the baseline period (1961-1990) to 19.3 days in the future (2071-2100). Peak discharge will increase by an average of 21% in the future in the projected climate change scenario. After statistics on changes of flood characteristics in the projected climate change scenario (2071-2100) were obtained, a 2-dimensional hydrodynamic model was used to obtain flood inundation and velocity distribution on the floodplain. Distribution of velocity and inundation depth was spatially analyzed to obtain flood hazard zones in the projected climate change scenario. Results show that spatial variation in flood hazard zones will be significantly altered in the projected climate change scenario compared to land use/land cover changes.
-  V. K. G. Arora and G. J. Boer, “Effects of simulated climate change on the hydrology of the major river basins,” J. Geophys. Res., Vol.106, pp. 3335-3348, 2001.
-  N. W. Arnell, “Climate change and global water resources,” Glob. Env. Change, Vol.9, pp. 31-49, 1999.
-  A. Baldassarre, A. Castellarin, A. Montanari, and A. Brath, “Probability-weighted hazard maps for comparing different flood risk management strategies: a case study,” Nat. Hazards, Vol.50, pp. 479-496, 2009.
-  D. Cameron, K. Beven, and P. Naden, “Flood frequency estimation by continuous simulation under climate change (with uncertainty),” Hydrol. Earth. Syst. Sc., Vol.4, No.3, pp. 393-405, 2000.
-  H. Chang and I. W. Jung, “Spatial and temporal changes in runoff caused by climate change in a complex large river basin in Oregon,” J. Hydrol., Vol.388, pp. 186-207, 2010.
-  B. Datta and V. P. Sing, “Hydrology,” in “The Brahmaputra Basin Water Resources,” V. P. Singh, N. Sharma, C. Shekhar, P. Ojha (Eds.), Kluwer Academic Publishers, Netherlands, pp. 139-195, 2004.
-  S. Dutta and M. Zade, “RISE – A distributed hydrologic model for Rice agriculture: concept and evaluation,” in “Watershed Hydrology,” V. P. Singh and R. N. Yadava (Eds.), Allied Publishers, India, pp. 240-251, 2003.
-  S. Ghosh and S. Dutta, “Impact of climate change on flood characteristics in Brahmaputra basin using a macro scale Distributed Hydrological Model.” J. of Earth System Science, Vol.121, No.3, Springer, pp. 637-657, 2012.
-  S. Ghosh and S. Dutta, “Impact of climate and land use changes on the flood characteristics of the Brahmaputra basin,” ISH J. of Hydraulic Engineering, Vol.17, Supplement-1, pp. 32-42, 2011.
-  S. Ghosh and S. Dutta, “Macro-scale distributed hydrological modeling for flood wave prediction in Brahmaputra river,” in Proc. of Workshop on Development and Application of Advanced Soft Computing Techniques in Multidimensional Geospatial Data Analysis (WAST2009), October 15-16 2009, IIT Kanpur, Kanpur, India, 2009.
-  B. N. Goswami, V. Venugopal, D. Sengupta, M. S. Madhusoodanan, and P. K. Xavier, “Increasing trend of extreme rain events over India in a warming environment,” Science, Vol.314, No.5804, pp. 1442-1445, doi: 10.1126/science.1132027, 2006.
-  D. C. Goswami, “Fluvial regime and flood hydrology of the Brahmaputra River,” Assam Mem. Geol. Soc. Ind., Vol.41, pp. 53-75, 1998.
-  L. P. Graham, J. Andreasson, and B. Carlsson, “Assessing climate change impacts on hydrology from an ensemble of regional climate models, model scales and linking methods-a case study on the Lule River basin,” Climatic Change, Vol.81, pp. 293-307, 2007.
-  T. Karmaker and S. Dutta, “Generation of synthetic seasonal hydrographs for a large river basin,” J. Hydrol., Vol.381, pp. 287-296, 2010.
-  A. L. Kay, D. A. Jones, S. M. Crooks, A. Calver, and N. S. Reynard, “A comparison of three approaches to spatial generalization of rainfall runoff models,” Hydrol. Process. Vol.20, pp. 3953-3973, 2006.
-  Z. W. Kundzewicz, L. J. Mata, N .W. Arnell, P. Doll, P. Kabat, B. Jimenez, K. A. Miller, T. Oki, Z. Sen, and I. A. Shiklomanov, “Freshwater resources and their management,” in “Climate Change 2007: Impacts, Adaptation and Vulnerability,” M. L. Parry, O. F. Canziani, J. P. Palutikof, P. J. van der Linden, C. E. Hanson (Eds.), Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, UK, pp. 173-210, 2007.
-  S. K. Mishra, R. Sarkar, S. Dutta, and S. Panigrahy, “A physically process based hydrological model for Paddy agriculture dominated hilly watersheds in Tropical region,” J. Hydrol., Vol.357, pp. 389-404, 2008.
-  N. S. Reynard, C. Prudhomme, and M. Crooks, “The flood characteristics of large UK rivers: Potential effects of changing climate and land use,” Climate change, Vol.48, pp. 343-359, 2001.
-  K. Rupa kumar, A. K. Sahai, K. K. Kumar, S. K. Patwardhan, P. K. Mishra, J. V. Revadekar, K. Kamala, and G. B. Pant, “Highresolution climate change scenarios for India for the 21st century,” Curr. Sci. India, Vol.90, No.3, pp. 334-345, 2006.
-  J. N. Sarma, “Fluvial process and morphology of the Brahmaputra River in Assam, India,” Geomorphology, Vol.70, pp. 226-256, 2005.
-  J. N. Sarma, “An overview of the Brahmaputra River System,” in “The Brahmaputra Basin Water Resources,” V. P. Singh, N. Sharma, C. Shekhar, and P. Ojha (Eds.), Kluwer Academic Publishers, Netherlands, pp. 72-88, 2004.
-  R. Soja and L. Starkel, “Extreme rainfalls in Eastern Himalaya and southern slope of Meghalaya Plateau and their geomorphologic impacts,” Geomorphology, Vol.84, pp. 170-180, 2007.
-  J. Wainwright and M. Muliagan “Environmental Modelling: Finding Simplicity in Complexity,” John Willey & Sons Lt., 2004.
-  S.Wang, R. McGrath, T. Semmler, C. Sweeney, and P. Nolan, “The impact of the climate change on discharge of Suri River Catchment (Ireland) under different climate scenario,” Nat. Hazard Earth Sys., Vol.6, pp. 387-395, 2006.
-  Y. Zhang, “CCHE-GUI – Graphical Users Interface for NCCHE Model User’s Manual – Version 3.20,” Technical Report No. NCCHE-TR-2008-01 The Univ. of Mississippi, 2008.
-  Y. Zhang and Y. Jia, “CCHE2D Mesh Generator Users Manual – Version 2.6,” Technical Report No. NCCHE-TR-2005-05 The Univ. of Mississippi, 2005.
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