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55 Wyoming’s North Platte water users have been in a relationship with the federal government and the mandates of the Endangered Species Act (ESA) because they have been beneficiaries of federal dams, reservoirs, river diversions, and canals that capture over 2.8 million acre feet of North Platte River water for irrigation and hydroelectric power. The U.S. Bureau of Reclamation (USBR) owns and manages—on behalf of four Wyoming irrigation districts and nine Nebraska districts—the infrastructure that has significantly altered stream flows, sediment loads, and consumptive uses across a wide stretch of high semi-desert. All of this federally constructed North Platte River plumbing meant that Wyoming water users, along with their Nebraska compatriots downstream across the state line and along the Upper North Platte above Lake McConaughy, would be in the grasp of federal environmental laws and regulations. North Platte River water users on federally funded and managed USBR irrigation projects must face the prospect of consultations with the U.S. Fish and Wildlife Service (USFWS) under Section 7 of the ESA and Section 404 of the Clean Water Act. Wyoming’s facilities are large and impose major impacts. Section (2c)(2) of the ESA declares that federal agencies shall cooperate with state and local agencies to resolve water resource issues in concert with the conservation of endangered species (Record of Decision 2006: 2–3). Background Wyoming’s boundaries encompass an ancient and gigantic mountain mesa, the C h a p t e r 6 Wyoming in a Federal nexus Defending the Mountaintop W y oM in g in a FeDer a l n exus 56 geologic nucleus of North America. Mountain peaks that hover over watersheds such as those of the Medicine Bow Range are merely pimples on the massive up-thrust that in many places consists of pre-Cambrian rock 4.1 billion years old, an impressive figure on a planet only about 4.6 billion years old (Knight 1990; Ostresh, Marston, and Hudson 1990). Colorado and Nebraska, by comparison, are geologic afterthoughts. The broad mountaintop that is Wyoming tends to level out in the southern part of the state and thereby afforded a path that provided the best route west for nineteenth-century folks of European stock who followed the Missouri, then the Platte main stem to North Platte, Nebraska, then the North Platte to Wyoming’s Sweetwater River, then over the Continental Divide to Utah, Oregon, or California. Today, Interstate 80—paralleled by the Union Pacific Railroad—roughly follows that same trail. The state’s history has been well told elsewhere (Larson 1965). Only about 15 percent of the state has an average annual positive water balance , meaning areas where more water is received from precipitation than is lost through evaporation and transpiration by way of vegetation. These areas are generally found in the mountains (Ostresh, Marston, and Hudson 1990: 24). At lower elevations, where cropping seasons are the longest, water balances tend to be negative—a fact that harshly constrains dry-land farming. Aridity, combined with high elevations and short crop seasons, has meant that the Wyoming postsettlement agricultural landscape has always been dominated by grass range for sheep and cattle. The agricultural and urban-industrial frontiers have been held in check. The state has the smallest population of the lower forty-eight U.S. states. Its urban centers, by the standards of most states, are little more than small towns. Old-timers are fond of saying that “the whole state is a small town, just with very long streets.” north Platte Water Projects The North Platte River originates in north-central Colorado near the Continental Divide and plunges through Northgate Canyon into Wyoming. Major Wyoming tributaries, capturing and channeling high-country snowmelt, feed the stream; the most prominent are the Encampment, Sweetwater, Medicine Bow, and Laramie rivers. After leaving Colorado, the stream flows in a northerly direction until it hits the slack waters of a string of federally constructed reservoirs. When released through gates at Seminoe and Pathfinder, some flow is diverted toward Kendrick Project lands at Alcova Dam. A larger annual fraction moves northeast to Casper, after which the river bends southeast to fill Glendo Reservoir, on to Guernsey Reservoir, then across the state line to western Nebraska panhandle country where—after multiple uses and return flows—it fills Lake McConaughy (Map 6.1). About 80 percent of the North Platte storage water pooled in Wyoming reservoirs is destined for Nebraska panhandle water users above Lake [3.138.105...

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