Rio Grande/Rio Bravo The Rio Grande/Rio Bravo is the second longest river in the United States and Mexico. Flowing over 1,900 miles (3000 km) from the high mountains of southern Colorado to the Gulf of Mexico, it is the center of life for countless people, plants, and animals. The Rio Grande/Rio Bravo is an international river, meaning that the basin from which its water flows is located on two sides of an international boundary or flows from one country into another. As such, there are a number of unique issues that must be addressed. For example, although rain may fall in Colorado, the water may not be used until the river carries it into Mexico. This means that communities, which seem unrelated, are highly interconnected by their mutual dependence on the river. Discover a Watershed: the Rio Grande/Rio Bravo has been tailored to address topics that are specifically related to the Rio Grande/Rio Bravo. Comprised of an educators guide, a KIDs (Kids in Discovery Series) activity booklet, and an issues investigation book. Link to Rio Grande/Rio Bravo Educators Guide Link to Rio Grande/Rio Bravo KIDS Activity Booklet (English and Spanish Editions) Link to "Investigating and Evaluating Environmental Issues in the Rio Grande/Rio Bravo Valley"