When it rains the water falls on the ground:
• Some of the water sinks and passes the earth in.
• Another part of the water goes to small streams.

Those streams gradually come together with other streams and also with water running down slopes and ravines, which end up forming small rivers.
These small rivers also meet other rivers.
These rivers can be found with a large river, called the major river.

The major river stream travels through much of a territory and its waters can reach a serene and deep lake; to a shallow, still lagoon; or to a main river, with plenty of water, that will reach the sea.

To all the territory, where this happens, it's called a “hydrological basin or watershed”.

The name of the main river gives the watershed its name,
for example, the Papaloapan River Basin,
the Grijalva River Basin, the Balsas River Basin,
to name just a few of the most important in Mexico.

And you, what basin do you live in?

Text: Helena Rivas López
Translation: Lilia de Jesús Villalba Almendra
Validation 1: CAED 147, Cuautla, Morelos
Validation 2: APAMA, Spain