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Moving Blue Mesa's Marketable Yield: A Myth 3. Water Rights for the Black Canyon of the Gunnison The Black Canyon of the Gunnison (see map located on inside cover) has sub- stantial water rights in the basin dating to 1933, the year the United States reserved it as part of the National Park system. Though the specific quantity and timing of these rights has yet to be finalized by the Water Court, the Gunnison River system may be re-operated so that the Black Canyon will again receive its legal entitlement to some of the spring peak flows and winter base flows that created it and that will keep it healthy for future generations. The Black Canyon and the Gunnison Gorge (immediately downstream from the Canyon) were carved by the forces of the Gunnison River over millions of years. Unobstructed by any human-made features, in average and above-average years, the river received spring peak flows-torrents that in wetter years were as great as 20,000 cfs or more. These spring peaks cleared out woody debris and carried sediment, grav- el, and large boulders down-canyon. This natural hydrograph developed a canyon environment every bit as dramatic as the Grand Canyon. Though only half as deep, the Black Canyon is many times narrower from rim to rim, an impressive gash of dark purple rock in a landscape of spare piiion and juniper forest. As a result of these natural processes over the millennia, the Black Canyon is home to a host of plants and animals, including bighorn sheep, deer, river otters, beaver, eagles, peregrine falcons, and several species of waterfowl. Listed as "gold medal waters" by the Colorado Division of Wildlife, the canyon is thought by many to be the best trout fishery in the state. It has tremendous cliffs, banks, beaches, and other wilderness features. The Black Canyon is a boon for human uses, too. Hundreds of thousands of people visit the area each year to sightsee, hike, camp, rock climb, kayak, raft, and fish. Visitors bring their pocketbooks, with undeniable economic benefit to the sur- rounding communities. According to National Park Service records, in 1995 the Black Canyon generated $12.3 million in sales, $1.1 million in tax revenue, and 307 new jobs.97 In short, the Black Canyon is a spectacular national treasure deserving of the water it needs to carry it into the next century. But the past century has brought increasing consumptive use of water upstream of the Canyon. And, since the mid-1960s, the Aspinall Unit has moderatbd flows substantially, cutting off the top of spring peak flows (to the point where the Gunnison River no longer transports significant quantities of sediment) and increas- ing winter flows to roughly twice their natural levels. These modifications in the natural hydrograph result from the Aspinall Unit release schedule, which maximizes hydropower generation at the expense of biologi- cal function. Blue Mesa and Morrow Point are "peaking facilities," and maximize releases during periods when power is in greatest demand and has the highest value. Crystal Reservoir's re-regulating releases tend to even out the flows; nonetheless, cur- rent operations of the Aspinall Unit create a huge irregularity in the River's heartbeat. • 26 • The Land and Water Fund of the Rockies