Lower Colorado River Valley

The Lower Colorado River Valley (LCRV) is a region along the lower part of the Colorado River in the southwestern United States. The river begins in the Rocky Mountains and flows all the way to the Colorado River Delta in the northern Gulf of California in northwestern Mexico, between the states of Baja California and Sonora. This part of the river creates a border between the U.S. states of California/Arizona and Nevada/Arizona, as well as between the Mexican states of Baja California and Sonora.

A section of the LCRV showing the Colorado Desert (yellow dotted line) in the west, the Salton Sea, and the three US bordering states on the Colorado River. Portions of the Mexican states of Baja California and Sonora also shown. Proximity to San Diego and the rain shadow of coastal mountains is also shown.

The LCRV is usually thought of as the area starting below the Hoover Dam and Lake Mead, stretching to the Gulf of California. It includes the river itself, canyons, valleys, mountains with wilderness areas, and flat areas near the water with plants that grow near rivers, called riparian environments.

This valley is a special place for many reasons. People enjoy fun activities like recreation along the river and the lakes made by big dams. It is also an important area for agriculture, meaning growing food. Many cities, towns, and communities are found here, as well as five Indian reservations: the Chemehuevi, Fort Mojave, and Colorado River Indian Reservations; and at Yuma, the Quechan and Cocopah reservations.

Ecology

The Lower Colorado River Valley has some of the hottest temperatures in North America, with places like Bullhead City, Lake Havasu City, and Yuma often feeling very warm. This area is part of three big deserts: the Mojave Desert, the Sonoran Desert, and the Colorado Desert. The valley stretches about 350 miles from Hoover Dam to the Colorado River Delta.

Plants and animals in this valley must survive with very little water and extreme heat. Common plants include white bursage and creosote bush, and you might also find Joshua trees and brittlebush. Some plants only bloom after rare rains. However, the valley faces many challenges, such as people moving in, farming, and activities like offroad driving that can harm the land.

Fauna

Main article: List of fauna of the Lower Colorado River Valley

Trigo Mountains Wilderness, a ridgeline wilderness area on the eastern border of the river proper, 30 miles north of Yuma–Winterhaven. A buckhorn cholla cactus is in foreground; creosote bush scrubland on hillsides.

Flora

The Lower Colorado River Valley has special plants that can handle very dry and hot conditions. Because there is little water, most plants have ways to keep from losing too much water. Common plants include white bursage, creosote bush, and many types of cacti.

_[Yucca brevifolia](/wiki/Yucca_brevifolia)_ (Joshua tree)

_[Abronia villosa](/wiki/Abronia_villosa)_ (sand verbena)

_[Eriogonum inflatum](/wiki/Eriogonum_inflatum)_ (desert trumpet)

_[Encelia farinosa](/wiki/Encelia_farinosa)_ (brittlebush)

_[Opuntia basilaris](/wiki/Opuntia_basilaris)_

_[Yucca schidigera](/wiki/Yucca_schidigera)_

Threats

The Lower Colorado River Valley faces several challenges that can harm its plants and animals. These include cities growing, people using land for farming, and activities like offroad driving. Taking wood for fuel and damaging the land can also be a problem.