PUB00155 - Laserfiche WebLink

Home Browse Search

~ initiating four different Supreme Court cases and could easily be the motivation for future interstate litigation. Additionally, as a lower elevation watershed, the Gila River's future may be in the most jeopardy due to future climate changes. The other two major sub-basins in the Lower Basin are the Little Colorado River Basin and the Virgin River Basin. The Little Colorado River Basin drains about 25,000 square miles of northeastern Arizona and west central New Mexico. The Little Colorado River has even less natural discharge per square mile than the Gila River. Reclamation estimated the average annual discharge of the Little Colorado at Grand Falls to be in the range of200,000 to 240,000 afper year.27 Grand Falls is about 60 miles upstream of the confluence of the Little Colorado River and the Colorado River in Grand Canyon National Park. Like the Gila, the Little Colorado River is a very flashy river. Its primary watersheds are the northern slopes of the Mogollon country and the White Mountains. Major portions of the Lower Little Colorado River mainstem are dry for most of the year. The Little Colorado River is politically important because it drains.and runs through the Navajo and Hopi Indian Reservations within Arizona and the Zuni Indian Reservation in western New Mexico. None of these tribes has quantified its reserved water rights. The Little Colorado River is environmentally important because after the completion of the Glen Canyon Dam, the Little Colorado is a primary source for sediment for the Grand Canyon river ecosystem. The very lower portion of the Little Colorado also provides habitat for the Humpback Chub, a native fish species listed as endangered under the ESA. The Virgin River and its tributaries drain very southwestern Utah, the very northwest comer of Arizona and southeastern Nevada. The Virgin River has its headwaters in the high country of southern Utah east of Cedar City. Its principal tributary in Nevada is the Muddy River. The drainage area is approximately 11,000 square miles.28 The estimated natural flow of the river at Littlefield, Arizona is 310,000 afperyear.29 The Virgin River and Muddy River flow directly into Lake Mead. When Lake Mead is high, location of the confluence ofthe two streams is underwater in Lake Mead. The Virgin River is politically significant for a number of reasons. The river is the primary source of water for southeastern Utah. The Washington County/St. George, Utah area is booming. In fact, the State of Utah is moving forward with the development of a pipeline project that would supply the St. George area with water from Lake Powell. There is no formal agreement among Arizona, Nevada and Utah dividing the waters of the Virgin River. However, there have been informal discussions among the three states. The second reason for the political importance of the Virgin River is that within Nevada, there are over 20,000 acres of irrigated lands in primarily the Muddy River Basin. Reclamation 27House Document 419, TABLE LXXIV, page 152. Again, remember that this is probably higher than the long term average. 28House Document 419, page 157. 29House Document 419, page 158. Page -12-