Author(s): Golam Saleh Ahmed Salem; So Kazama; Daisuke Komori; Shamsuddin Shahid; Nepal C. Dey
Linked Author(s): So Kazama
Keywords: Global climate models; Sustainable water use; Northwest Bangladesh
Abstract: Climate change alters hydrological processes, groundwater recharge and groundwater level which in turn, increase irrigation cost. Identification of necessary adaptation measures is very important for sustainable management of groundwater resources and ensuring farmer’s profit. The objective of this study is to assess the impact of climate change on groundwater level and it’s consequence on irrigation cost in order to propose necessary mitigation measures in Northwest Bangladesh. An ensemble of four global circulation model (GCM) simulations of Coupled Model Intercomparison Project phase 5 (CMIP5) namely, BCCCSM1-1, Can ESM2, MIROC5 and MIROC-ESM under Representative Concentration Pathways (RCP) scenario (RCP) 4.5 are used to project future changes in climate in the study area. A support vector machine (SVM) was used to model the temporal variation of groundwater level from rainfall, evapotranspiration, groundwater abstraction and irrigation return flow. A multiple linear regression (MLR) model was also developed to estimate irrigation cost from groundwater level, crop schedule and irrigated area. The study reveals that average groundwater level will go down by 1.3 m during irrigation period, which in turn will increase irrigation cost by 0.38 thousand Bangladesh currency per hector. It is expected that the study will help to build resilience in groundwater based irrigation system in the context of climate change.