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

~
~.
~,

GENERAL

.~~
~i~;!

t~-I".~;~~

I

f;~i;;:~_,

flX"i..

~.,'~~

I
II

fl,;
f{9

Or' '; Q ('
U j..L.: (_,q

~
~

STATUS REPORT NO. 10

"!
~
~]

',"I
~~
~::

This status report covers ,the monitoring program of Rainbow Bridge
from October 1, 1977 to March 31, 1978. During January 1978, sur-
veys and elevations were recorded at established quadrilaterals at
Rainbow Bridge and along Bridge Creek Canyon, a series 'of photo-
geology photographs were taken at all photopoints for comparison
with previous photographs, and readings were obtained from all
strain gauge stations, which monitor the movements of selected
cracks on Rainbow Bridge. Strain gauge stations Nos. I and 5 were
also read monthly to get a more complete picture of crack motion.
Seismic data was also obtained from a newly installed seismograph,
located about one mile west of Rainbow Bridge.

~i',
~.
Si

I

f"l
t"
~}

As explained in previous status reports, all motion recorded by the
surveys and strain gauge readings indicates a cyclical pattern which
repeats itself on a daily and yearly basis. Seasonal temperature
changes are responsible for this motion, both in the cracks of the
Bridge and in the rock itself. The minor deviations in readings
from day to day and one year to the next ar~ the combined result of
weather patterns and exposure time to the sun.

~~
p
<\,::.1

'i'"
f.._~
t

The information gathered during this report period indicates that
the structural integrity of Rainbow Bridge and foundation has been
maintained, and no adverse effects have been observed by the
incursion of the reservoir into the Monument.

"~
r~:
{"
,.,.'
.'
/;.,

",...~
''",'
it

SPECIFIC COMMENTS

Iw'
J.i.~
'.
.,

The following comments are a brief explanation of the purpose and
procedure of the different monitoring programs and an analysis of
the data obtained during this report period.

i'T
&~1

1. Bridge Creek Canyon Quadrilateral Surveys

~"'l
(''(J
~i.~
;z.:r

A meaningful basis for comparison and analysis of the Rainbow Bridge
structure and foundation can be provided by the surveying technique
of triangulation, by which exact distances between two points are
found. This technique is applied at Rainbow Bridge by establishment
of four horizontally-oriented quadrilaterals.

:.:~.";l
:;,1
~;;'.1
~<-'~

"'-.-_:-~~-':'-;:.-
-. ....
':~;- -.~~" :;..:
'," .::>.;.':
i~t:~!)i.;
. ...,

;"-:~ '. ~'. - ."
<: . -"'~-',;.~.: '.-
';:'--'.;'.

jE9~::~;

~;,J~~!~~~$.~1~l~$#~~1tt~~1~~~;j}~J~~~~I~:~1~~t~~!l~~!~~~;.!~t~fffJi;~f;~~~~~~f.~;~(~i~if[~1~5.~1~fg~~~~~f!f{~1~t~~~:;;'