Eddie Dyer, age 11, of Beaumont, Tex., for his question:
HOW LONG IS THE RIO GRANDE?
Fifth longest river in North America is the Rio Grande. It flows for 1,885 miles through the Southwestern United States and it forms the international boundary between the United States and Mexico for about 1,240 miles, or almost two thirds of the common border.
Early Spanish explorers gave the river its name. Rio Grande means large river. Many Mexicans call the river Rio Bravo, or bold river. Others call it Rio Bravo del Norte, or bold river of the north.
In the southern Rocky Mountains in southwestern Colorado, on the Continental Divide, the Rio Grande rises. It flows southeast through the San Luis Valley Reclamation Project. At Alamosa, the river turns south.
The Rio Grande crosses into New Mexico and flows from north to south through the center of the state. In northern New Mexico, the river is fed by other mountain streams, such as the Brazos and the Chama rivers. It passes through a series of basins separated by narrow valleys.
Above Albuquerque the Rio Grande's valley widens and the river flows out upon a dry plateau. Here Elephant Butte Dam impounds the river for about 40 miles. Farther downstream is the Caballo Reservoir. Both of these lakes store water.
The American Dam controls the waters of the Rio Grande north of E1 Paso at the Texas, New Mexico and Mexico borders.
From E1 Paso to the Gulf of Mexico the river forms the international boundary. The river flows southeast from E1 Paso to Presidio, where it turns north to pass around the mountainous Big Bend country. It then flows eastward until the Pecos River joins it. The river then turns southeast for the rest of its course.
Amistad Dam spans the river about 12 miles northwest of Del Rio, Tex. The dam forms Amistad Reservoir which extends upstream for 86 miles.
Near the Rio Grande's lower course, the river may be dry in late summer because of little rainfall and the amount of water used for irrigation.
About 50 miles below Laredo, the Salado River, a major tributary from Mexico, joins the Rio Grande. Falcon Dam, about 20 miles below the mouth of the Salado River, forms Falcon Reservoir, which extends upstream more than 35 miles.
At Rio Grande City is the Los Olmos Reservoir on another tributory, the Rio Los Olmos. Lake E1 Azucar lies across the Rio Grande at Camargo in Mexico.
At Mission, farther downstream, is Mission Reservoir which was built jointly by the United States and Mexico to hold back floodwaters for the lower valley's irrigation projects.
Between Rio Grande City and Brownsville, farmers grow citrus trees, vegetables and cotton in the irrigated valley.
In 1936, a 17 mile canal was built from Brownsville to Laguna Madre, with jetties through the barrier beach to the Gulf of Mexico.