San Juan River
Context
The floodgates of the El Cuchillo Dam in Nuevo Leon after Mexico opened them to send water through the San Juan River to the U.S. to settle its water debt under the 1944 Water Treaty.
What it means
El Cuchillo Dam is a major reservoir in northern Mexico.
It was opened to release water into the San Juan River, which ultimately feeds into river systems shared with the U.S.
Mexico did this to repay a water shortfall (“water debt”) under the 1944 Water Treaty with the United States.
Why this happens
Under the 1944 treaty, Mexico must deliver a fixed quantity of water every five-year cycle from certain tributaries of the Rio Grande.
During drought years, Mexico often falls behind and later releases large volumes at once to meet its obligation.
The San Juan River is one of the most important tributaries of the Colorado River.
About San juan river
It originates in the San Juan Mountains of southwestern Colorado.
The river flows through New Mexico and southeastern Utah, cutting through deep canyons and desert landscapes.
It joins the Colorado River in Lake Powell, upstream of Glen Canyon Dam.
Colorado River:
The Colorado River is one of the most important rivers of the southwestern United States and northern Mexico.
Origin and upper course
The river originates in the Rocky Mountains of Colorado.
It flows for about 1,450 miles (2,330 km) from its headwaters to the Sea of Cortez/Gulf of california in Mexico.
Before entering Arizona, it is joined by its largest tributary, the Green River, which flows south from Wyoming.
The river cuts through the mountains of Colorado and the canyonlands of Utah, carving deep gorges.
Lake Powell and Glen Canyon
In southern Utah, the river enters Lake Powell.
Lake Powell was created by the Glen Canyon Dam, located just south of the Arizona–Utah border.
This dam is crucial for hydropower generation, water storage, and regulation of downstream flows.
Middle course: Grand Canyon and Lake Mead
Below Glen Canyon Dam, the river flows through the Grand Canyon for more than 200 miles, creating one of the world’s most iconic erosional landforms.
It then enters Lake Mead, formed by the Hoover Dam.
Hoover Dam is a major source of electricity, irrigation water, and urban supply for the southwestern U.S.
Prelims Practice MCQ
Q. Consider the following statements about the San Juan River:
It originates in the San Juan Mountains
It joins the Colorado River downstream of Hoover Dam
It flows across canyonlands of the Colorado Plateau
Which of the statements given above is/are correct?
(a) 1 and 2 only
(b) 1 and 3 only
(c) 2 and 3 only
(d) 1, 2 and 3
Correct answer: (b)
Explanation:
Statement 1 is correct: It rises in the San Juan Mountains.
Statement 2 is incorrect: It joins the Colorado at Lake Powell, upstream of Hoover Dam.
Statement 3 is correct: It flows through canyonlands of the Colorado Plateau.