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The Lower Colorado River Valley ("LCRV") is the river region of the lower Colorado River of the southwestern United States in North America that rises in the Rocky Mountains and has its outlet at the Colorado River Delta in the northern Gulf of California in northwestern Mexico, between the states of Baja California and Sonora. This north–south stretch of the Colorado River forms the border between the U.S. states of California and Arizona, and Nevada and Arizona;〔"Lower Colorado River Valley" section, Center for Sonoran Desert Studies; ()〕 also between the Mexican states of Baja California and Sonora. It is commonly defined as the region from below Hoover Dam and Lake Mead to its outlet at the northern Gulf of California (Sea of Cortez); it includes the Colorado River proper, canyons, the valley, mountain ranges with wilderness areas, and the floodplain and associated riparian environments. It is home to recreation activities from the river, the lakes created by dams, agriculture, and the home of various cities, communities, and towns along the river, or associated with the valley region. Five Indian reservations are located in the LCRV: the Chemehuevi, Fort Mojave and Colorado River Indian Reservations; at Yuma are the Quechan and Cocopah reservations. ==The LCRV, a desert region== Some of the highest absolute air temperatures (of North America) are recorded in the LCRV, rivaling Death Valley; specifically Bullhead City, Lake Havasu City, Laughlin, Needles, Yuma, or the southeastern deserts of California, west of the Colorado River where extreme heat is the main summertime weather feature. Worldwide, only deserts of the African continent and of the Middle East stand up with an even hotter summer climate. The LCRV is defined by three deserts. The Mojave Desert is in southeast California, southern Nevada, and northwest Arizona. To the south is the Sonoran Desert on both sides of the Colorado River. However an ecozone delineation occurs in the transition from Arizona to southeast California; consequently the western side of the Colorado River is defined as the western Sonoran Desert and given the name Colorado Desert; the ecozone of this western Sonoran Desert extends south into the northwest region of Sonora, Mexico and the extreme northeast of northern Baja California, Mexico. The Lower Colorado River Valley is located in the north, and northwestern Sonoran Desert; the Sonoran Desert region proper extends from areas west of the river, and then southeastwards to southeast Arizona, south to the tip of Baja California Sur, eastwards of the Baja Peninsula cordillera, and south through Sonora state, Mexico to the northern border of neighboring Sinaloa. The LCRV extends about from Hoover Dam to the Colorado River Delta. The Sonoran Desert itself is more than twice as extensive north-to-south, and about in width. Two species, Desert Ironwood-(''Olneya tesota'')〔''Atlas of United States Trees, Volume 3, Minor Western Hardwoods'', Map 103-''Olneya tesota''〕 and the Lesser Long-nosed Bat, have geographic ranges identical to the Sonoran Desert, and are indicator species of the ''Sonoran Desert region''. The spring flowering of Ironwood, and the bat species migration arrivals also become indicators of annual or multi-year climate trends for regions of the Sonoran Desert. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Lower Colorado River Valley」の詳細全文を読む スポンサード リンク
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