Paleohydrology is the study of ancient water systems and their changes over time. It examines how rivers, lakes, and groundwater have evolved, providing insights into past climates and environmental conditions. By analyzing sediment layers, fossils, and chemical signatures, scientists can reconstruct historical water flow and availability. This field is important for understanding how water resources have influenced human civilizations and ecosystems. It also helps predict future water availability in the context of climate change. Researchers often use data from geology, archaeology, and paleoclimatology to build a comprehensive picture of ancient hydrological systems.