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<br />redistributed the sediment dowpstream and contributed additional
<br />sediment to the reservoir within Bridge Creek Chapnel. The reservoir
<br />was at elevation 3647,75 at the time of the flash;"flooding or 22.64
<br />feet below the elevation of the reservoir during the flash flood of
<br />July 31, 1976 (see combined Status Reports 6-9). With this lower
<br />elevation, the sediment pattern was consequently reestablished
<br />downstream.
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<br />These flash floods and resulting sedimentation have produced no
<br />apparent or measurable effect on the structural stability of the
<br />Rainbow Bridge structure or foundation.
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<br />10. Meteorologic Data
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<br />Due to functional problems encountered by the weather barge, some of
<br />the data obtained was incomplete and/or unusable. A summary weather
<br />data sheet of the good data available for this time period is included
<br />in this report.
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<br />11. Ecology Environmental Effect
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<br />As indicated in the last status report, the dislocation and stirring
<br />of sand, gravE,l, and cobbles by visitors to the Monument is having
<br />a slow but stE',adily noticeable ef:t;ect along visitor pathways. It
<br />appears that t.he material is loosened by foot travel'with the sand
<br />and silt size particles being blown away by the wind and the gravel-
<br />cobble, sizes being thrown into the reservoir by humans. Midway between
<br />Courtesy Dock and the Bridge, erosion can be seen at the visitor regis-
<br />tration box and a park bench, where the cement footings, originally at
<br />ground level, are now several inches above the ground.
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