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<br />30 <br /> <br />Powell, the beaches downstream are eroding due to the river's clear, sediment-free flows <br />(Kearsley et aI., 1994), Camping beaches are also being eroded through gullying induced by <br />monsoon rainstorm runoff, and due to the lack of periodic floods, these increasingly degraded <br />beaches are not being replenished. Most pre-dam beaches are now considerably smaller, and <br />some have disappeared completely, The size and availability of camping beaches is directly tied <br />to visitor experience parameters in that the decreasing size, abundance, and distribution of <br />campsites constrains the visitor carrying capacity of the CRE and may lead to crowding or <br />reduction in visitor access, thereby creating adverse impacts to visitor use values in the CRE. <br />In 1994, change in campable area was analyzed using aerial photographs (Kearsley et aI., <br />1994), This analysis revealed that loss of campsites was an ongoing process, They noted that <br />not all sand bars responded in the same manner to flows and vegetation encroachment, and that <br />campsite availability in critical reaches (Marble Canyon, the Inner Gorge, and the Muav Gorge) <br />had decreased the most. Effects of the 1996 controlled flood at selected campsites were also <br />evaluated, and it was found that the increase in the number and size of campsites was of short <br />duration (Kearsley et al. 1999), The post-BHBF data indicated that while floods temporarily <br />increased campsite number and size, the beneficial effects to campsites were temporary, and that <br />campsite size rapidly degenerated to pre-BHBF levels and then continued to erode more slowly. <br />Although the effects of the 1996 artificial flood were temporary, periodic "floods" above power <br />plant capacity appear to be the only feasible means of depositing sediment and rejuvenating <br />camping "beaches" above normal fluctuations (Kearsley et aI., 1999). <br />One previous study assessed recreational preferences relative to dam-controlled flows <br />and quality of camping opportunities (Stewart et al. 2000), The study concluded that users of the <br />Colorado River were relatively unconcerned about impacts of fluctuating flows, had strong <br />concerns (generally positive) about impacts of spike flows, and strongly preferred sandy beaches <br />with shade (especially from trees) for camping, <br />Recent and Onfloinfl Recreation Investiflations: Recent GCMRC studies have assessed <br />camping beaches, trout fishing activities, and recreational river running in terms of visitor <br />experience issues and safety concerns associated with varying flow levels. Low Steady Summer <br />Flows in summer 2000, provided data on impacts to recreational experiences (Jonas and Stewart <br />2002), travel rates and safety (Jalbert 2001) and economic impacts to concessionaires (Hjerpe <br />and Kim 2001), Final reports have been received for all projects except the safety study, <br /> <br />GCMRC FY2005-2006 Draft Annual Work Plan (November 10,2003) <br />