Study on sustainability of groundwater resources in Rajshahi district of Bangladesh

Abstract

Bangladeshis predominantly anagricultural countrywhereagriculturesector plays a significant role in accelerating the economic growth of the country. It is therefore important to have a sustainable, environment-friendlyand profitable agriculturalsystem in order to ensure long-term food security. Agriculture in Bangladesh is largely dependent on groundwater resources. But this scarce groundwater resources have been decreasing alarmingly in Rajshahi district which is one of the most drought prone districts and driest place of Bangladesh. This situation has threatened the sustainability of agriculture in this area at present as well as in the near future.Over abstraction of groundwater, lack of surface water bodies, low rainfall, high elevation, thick clay layer are the major hindrances in the study area to sustain groundwater resources. As a result, groundwater level in this district is successively falling in each year. In this study it has been strived to sustain this valuable groundwater sources for the sustainable agriculture of this region.

An integrated Surface Water- Groundwater base model from 2012 to 2016 has been developed, calibrated and validated. It has helped to understand current situation of the study area. In order to sustain groundwater resources up to year 2030, it is needed to foresee future condition of groundwater resources from 2017 to 2030. For this reason, there are ten (10) scenarios have been chosen to understand future groundwater condition in the study area by considering different driving forces such as Rainfall, Evaporation, Groundwater Level, Surface Water Level, and Water Demand. These scenarioshave been analyzed to identify the most extreme future scenario that is needed to be countered by applying suitable interventions.

Model output has been analyzed on eight Upazilas (Upazila wise) to understand the condition of groundwater precisely instead of taking study area as a whole. In spite of having different climatic conditions, soil type, cropping pattern, water demand and water availability most of these Upazilas have shown similar result. Scenario number 10 (S-10) has been found the most extreme scenario in most of the Upazilas (six out of eight). There are three interventions have been considered out of which intervention 1 (I-1) has shown significant result towards sustainable groundwater resources. In intervention 1, crop diversification technique has been applied by substituting high water consumed Boro rice by low water consumed Wheat and the outcome is remarkable. Groundwater resources of 96.55% of the study area has improved and additional 3620 million cubic meter saturated zone is increased in the study area in the most extreme event (April, 2028) of most extreme scenario. Moreover, all analysis has been done to counter the driest event (April, 2028) of worst scenario so that reaming events could be could be countered. Based on analysis it can be said that this intervention will be a suitable solution to sustain groundwater resources for future in this area. The results that have been found from this study will be very much helpful to carry out further studies in future.