GIS stands for Geographic Information System. It's like a special computer program that helps people make maps and store information about places on those maps.
Hydrology is about studying water, like how much there is, where it goes, and how it affects things. Kind of like a big game of connect the dots. Scientists use hydrology to help understand things like floods, water pollution, and water shortages.
Now, when we put GIS and hydrology together, we can make maps that show us things like how much water is in a particular area, where it flows, and what effects it might have on the land and people.
Take for example, a river. With GIS, we can make a map that shows where the river starts, where it flows, and where it ends up. We can also look at things like the different elevations of the land and the types of soil in the area. All of this information helps us understand how the river affects the land around it, how it may flood or erode, and how people may be impacted.
It's like having a big puzzle, and by using GIS and hydrology, we can fit all the pieces together to see the big picture of how water affects the world around us.