Impacts of climate change on command area development of Teesta barrage project

Abstract

The impacts of climate change on agricultural rood production are global con~em.<"and they are very important for Bimgladesh, Climate change may have repel'eussions 00 \h~ command al'ea developmcnt of Phase-Il of' the Tecsta Barrage PrOject (TBP), whIch is now at the implementation ,tage. This study was a~comp]jshcd to find out the p()s~lhlc effects of climate ehangc on TBP and thc possible mitIgation mcasures. A farmers' sLlf\'ey was conduded to assess the famler;' awareness about climate ~hange and possible mitigmlOll measures. Discussilln meetings with onieials of TBP were also held to assess th~ preparation of the projed authority in mitigating the adverse effects of climate change. In this stLldy, mClGorological data "ere taken from the pre<!ldion of Hadley Centre's generated two climate models (HadCM3 and PRECIS) with A2 and B2 scenario, and the Ilow of Teesta river was taken ii-om the outputs llf CLAS1C project, for the future horimn.<' of 2025 and 2050 From the analysis, it "as found that due to climale ~hange the fllture crop water requirement "0uld increase by 2,8% to 9.2% and 1.7% to 21.0% for PhusI:'-1and Cor Phase-ll by 4, I% to 10,3% and 3.1% to 14.9% for the projection year:<:l)f 2025 and 2050. respecti\'ely compared to the baseline perilld or 1990. Similarly, for the ,ame projedlon years, the rainfall would de~rease by 0.2% to 8.6% and 1.6% to 19,0% for .Phas~-I and for Phase-II by 7.0% to 23.7% and 3.0% to 151%. As a result. the future 110" 01 Tee.lta river would decrease during the critical period llf Odobcr by ILl % to 20,l"la. 28.9% to 31.4% and 23.9% to 30.6% in 2025 and by 5.4% to 24,8%, 15.3% to 32.8% and 12,2'"" to 23.0% in the project year of 2050 for the 1",2nd and 3IT! decades, respedlve1y Dunng the 1" and 2nJ decade~ or Odoher the scheme water reqUlrement may exceed the maXl1ntLmcapac,ty (283 m'/sec) of the canal head regulator, All models ,howcd that \\ith the present noppmg pattern the TBl' may face problem to meet the future increased demand due to the ad\"er~e effects of climate change, It should be noted that, because or ~oar:<;cresolution, variability and uncertainty in assumptions made and secnarios developed, the results or the climate change models arc only indicative, From the t~ehnieal feasibility analys;' "[possible tlutigatlon measures it wa.' r~vea1cd that by shifting to earlier transplanting dates or by introducing short duration Amall vanety, ll" po~sible to evade the shortfall in discharge of Tecsla river during the critical ]Jenlld "f' Odober K"L"j1ingthe present transplanting scheJuk, angmentation of the water availabliily for migatllln dLlring October is feasible either by rainwater harvesting through oll"fann reservoir or by inlernal river linking to the TBP. From the farmers' survey it "as evident that thcy are totally unaware of global warTllll1gand climate change but they have observed some changes 1Jltheir local climate. When asked about, the adoption ()f technically feasible climate ~hange mlllgalion OpIlOllS,the oll-fann reservoir was unacceptahle lO them as it takes away land penmmently out 01' productlOn. Farmers were not \'ery enthu,iastlC ahout either earlier transplanting or shorl duration variety but would adopt them if necessary. The project officials beheve that the futllre climate change scenario would nllt be as ,e,ere as predicted by the models due 10 spatial variation of climate, At present they have no preparation to mitigate the adverse impacts of climate change but would opt for flow augmentution Ii-om thc lJltcmal rivers if needed.