Site suitability analysis for the construction of water reservoirs in drought‐prone areas of Bangladesh using geospatial techniques

Abstract

AbstractDrought is becoming a common phenomenon in the northwestern (NW) region of Bangladesh. To address this problem, the government has taken multiple initiatives such as the construction of deep tube wells, re‐activation of abandoned deep tube wells, re‐excavation of canals, construction of cross dams, and digging wells to hold water during monsoon. However, the construction of medium‐ to large‐sized water reservoirs is somewhat overlooked or missed, which can hold large quantities of surface water and, at the same time, can recharge groundwater. Finding suitable sites for water reservoirs is a challenge. The present study aims to fulfill these gaps. We have applied a spatial multi‐criteria technique called the analytical hierarchy process (AHP) to identify suitable sites for water reservoir construction in the drought‐prone NW region of Bangladesh. A total of 12 criteria such as settlement, land use, slope, soil, groundwater depth, road network, river network, vegetation cover, rainfall, geology, protected areas, and aquifer depth were selected. The study shows that 17 percent of the area is highly suitable for reservoir construction, followed by 24 percent moderately suitable and 25 percent marginally suitable. In contrast, approximately 30 percent of the area is unsuitable for reservoir construction. Among 16 districts of northwest region, areas of Rangpur district are mostly suitable (30 percent), followed by Gaibandha district (16 percent). Construction of water reservoir in the identified areas will lower irrigation water pumping costs and will raise groundwater levels in land adjacent to the reservoir in dry season.