The researchers studied water levels along River Benue floodplain in Nigeria to see how water availability changes during dry and rainy seasons. They used instruments to measure water table heights and found that in the dry season, the river loses water to the surrounding area, while in the rainy season, the surrounding area loses water to the river. The direction of groundwater flow varies in different parts of the floodplain, with the river being the main source of water recharge during the dry season.