WSP04101

• File Number: 8080
• Description: Section D General Interstate Litigation - Rainbow Bridge Monitoring Program
• State: CO
• Basin: Statewide
• Date: 5/21/1964
• Author: DOI-BOR
• Title: Rainbow Bridge Monitoring Program - Reports 4 through 10
• Water Supply Pro - Doc Type: Report/Study

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RAINBOW BRIDGE NATIONAL MONUMENT MONITORING PROGRAM

Status Report No. 4
January 1975

INTRODUCTION

This is Status Report No.4 on the monitoring program of Rainbow Bridge

National Monument.

It covers the period from September 1974 to

January 1975 with some reference to prior reports.

During the eurrent

,coverage Lake Powell dropped from a maximum elevation of 3667.35 on June 30,

1974, to elevation 3648.27 on December 31, 1974.

Prevailing average,

temperatures during the period of September through November ranged from
740F. to 480F. in the Lake Powell area.

GENERAL

During this reporting period additional surveys were performed,on
established quadrilaterals at Bridge Creek Canyon and Rainbow Bridge.
Existing Whittemore Strain Gage Stations on the legs of the bridge were
remeasured and a supplemental set of deeper seated stations 'were installed.

The Bridge Creek Canyon sediment sections were resurveyed.

A raft containing meteorological equipment was anchored in Bridge Creek
Canyon. The USGS Branch of Seismicity and Risk Analysis was funded to
establish a microseismic earthqupke monitoring station at Rainbow Bridge.

Detailed rock mechanics testing of the Navajo and Kayenta rock from

Rainbow Bridge and Bridge Creek Canyon have been completed by the

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