Groundwater Potential Assessment in the Intensive Agricultural Zones of Kishoreganj District, Bangladesh Using GIS and AHP

In the fertile plains of northeastern Bangladesh, water is the lifeblood of the harvest. For generations, farmers have relied on the earth's hidden reservoirs—groundwater—to keep their rice fields green when the rains stop. This water sits in the spaces between soil particles and cracks in the rock deep below the surface, waiting to be drawn up by pumps. However, as populations grow and farming becomes more intense, the demand for this invisible resource has surged, often outpacing nature's ability to refill it. When too much water is pulled out, the levels drop, leaving wells dry and threatening the food supply. To manage this delicate balance, scientists need to know exactly where the water is most likely to be found and where it is scarce. They look for clues in the landscape above: the shape of the land, the type of soil, the pattern of rivers, and the cracks in the ground that allow rain to seep down. By mapping these features, researchers can predict which areas are rich in water and which are running dry, offering a guide for sustainable farming.

In the Kishoreganj District, a region known for its intensive agriculture, a team of researchers set out to create such a guide. They faced a pressing question: where is the groundwater most abundant, and how does this availability match the intensity of farming in the area? To answer this, they combined three powerful tools. First, they used satellite imagery and digital maps to see the land from above, capturing details like elevation, slope, and how the land is used. Second, they applied a method of logical ranking, similar to how a judge might weigh different factors to make a final decision, to determine which landscape features mattered most for holding water. Finally, they layered all this information together on a computer map to paint a picture of the district's water potential. Their goal was not just to find water, but to understand if the farmers were trying to grow too much in places where the water simply could not keep up.

The researchers gathered ten different types of information to build their map. They looked at the density of cracks in the ground, known as lineaments, which act like underground highways for water. They measured the slope of the land, noting that flat areas allow water to soak in while steep slopes cause it to run off. They analyzed rainfall patterns, soil types, and the presence of rivers and lakes. They also considered how rough the terrain is and the curvature of the land. Each of these factors was given a score based on how well it helped water reach the underground aquifers. For instance, areas with many cracks and gentle slopes received high scores for their ability to recharge, while steep, rocky areas received lower scores. By combining these scores, the team generated a detailed map that divided the district into five zones: very low, low, moderate, high, and very high potential for groundwater.

The results revealed a striking pattern across the district. The western and central parts of Kishoreganj, which are heavily farmed, were found to have very low to low groundwater potential. In contrast, the eastern regions showed high to very high potential, meaning they are naturally better suited for storing water. The map showed that about 31 percent of the district falls into a moderate category, while roughly 21 percent is high and 9 percent is very high. The remaining areas, covering about 39 percent of the land, are classified as low or very low potential. To ensure their map was accurate, the team checked their predictions against real data from 27 wells in the area. The comparison showed a strong match, with the model correctly predicting the water conditions in most of the tested locations, giving them high confidence in their findings.

Perhaps the most significant discovery was the mismatch between where the water is and where the farming is most intense. The researchers found an inverse relationship: the areas with the highest farming activity were often the ones with the least groundwater. In specific upazilas, or sub-districts, such as Hossainpur and Kishoreganj Sadar, farmers are growing crops on more than 220 percent of the available land area, meaning they are harvesting multiple times a year on the same fields. Yet, these same areas sit in the zones with the lowest groundwater potential. This creates a dangerous situation where the demand for water far exceeds the natural supply, putting the long-term sustainability of the region at risk. Conversely, the eastern upazilas like Kuliarchar and Bajitpur, which have the best conditions for groundwater, are actually used less intensively for farming.

The study concludes that the current farming practices in the western and central parts of Kishoreganj are likely unsustainable. The heavy reliance on groundwater in areas where it is naturally scarce suggests that the aquifers are being drained faster than they can recover. The researchers suggest that this imbalance needs to be addressed through careful planning. They recommend that water management strategies be tailored to specific zones, protecting the high-potential areas from overuse while finding alternative water sources or less water-intensive crops for the low-potential, high-demand zones. By understanding the hidden geography of their water, policymakers and farmers can make better decisions to ensure that the land remains productive for generations to come. The map serves as a clear warning: in the race to feed a growing population, the limits of the earth's hidden water must be respected.