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<br /> <br />::-:) <br /> <br />i\~ <br />~ <br />~ <br />qt <br /> <br />,.<:'.' <br /> <br />PI~nning <br />Issues/Backgraund <br /> <br /> <br />If it is the aesthetic aspects .of this landscape that stirs <br />human imaginatian, it was the ecanamic patential .of the <br />Calarado in an arid region that interested developers. In <br />1935, Hoover Dam was campleted at the lower end of <br />Grand Canyon and 28 years later, in 1963, Glen Canyon <br />Dam was completed, and thereafter controlled the river's <br />flow at the head of the canyon. <br /> <br />80th of these projects were to have an impact an river <br />running through the Grand Canyon. lake Mead, formed <br />by Haover Dam, extended inta the lower section of the <br />canyon, producing slack water that marked the end of the <br />free-flowing Colorado. Glen Canyon Dam's effects have <br />been mare dynamic. The amount of sediment and drift- <br />wood that was formerly carried naturally along the river's <br />course through the canyon has been significantly <br />reduced. Water releases from Glen Canyon Dam (a <br />primary function .of which is to generate hydroelectric <br />pawer) have created more predictable seasonal water <br />levels but have resulted in extreme daily fluctuations. <br />Canyon beaches, which provide campsites for river <br />runners, no longer receive sediment and are being eroded <br />with erratic daily flows. During periods of low flow, <br />passage at certain rapids has become difficult, creating <br />hazards and delays. Previaus heavy spring runoffs no <br />longer scour the Calorado's banks, and a new ecasystem <br />has grawn up in the pre-dam flaad zane. <br /> <br />There are ather influences that could affect river <br />management in the future that are .outside the scape .of <br />this planning effart. Far example, the Bureau .of <br />Reclamation is presently studying the passibility .of <br />canverting Glen Canyan Dam ta a peaking power <br />facility. This canversion wauld result in even greater <br />fluctuatians, in daily water fl.ow than now .occur. The <br />sharp fluctuatians, particularly periods of very low flows, <br />could make river running with large rafts or waaden boats <br />extremely difficult, if nat impassible, and accelerate <br />beach erasion and related impacts. <br /> <br />The desire .of the American public to experience this <br />unique part .of their natural heritage has dramatically <br />increased. In 1967,2,100 people made the river trip. The <br />number had jumped to 16,500 in 1972. This'sudden rise in <br />use was naticeably impacting the vulnerable inner canyon <br />ecosystem. Trash, charcoal, and human waste were <br />accumulating, multiple trails were developing ta points of <br />interest, and the numerous prehistoric and historic sites <br />near the river were being damaged. <br /> <br />3 <br /> <br />I <br />