|
<br />:;?"~1r_..,,-,:.;,.::.~,,,,,~,"J- ,,';:'1~,";:" ~::;::;~, :":O-J:,;~,.,,,,,,,,'~'~'n""". :oW, ,_.." .,.-;".;E.< "'''''"'..,.''-'''_. ," ~'~';:.._.,,,r._. 0._";, "-,;,, .' '~'_~""""'___'A""'~''-''''';'-:~' .-' >" .;,'" '. .'U.",--;-'......
<br />
<br />,~
<br />in
<br />.....
<br />'::: ,.32
<br />
<br />
<br />RIO GRANDE COMPACT COMMISSION REPORT
<br />
<br />~~ ')
<br />c;:
<br />
<br />ACCURACY OF RECORDS
<br />
<br />The Rules and Regulations of the Commission state that the equip-
<br />ment, method, and frequency of measurement at each gaging station shall
<br />be sufficient to obtain records at least equal in accuracy to those
<br />classified as "good" by the U.S. Geological Survey. Within the
<br />physical limitations of stream gaging, the agencies obtaining the
<br />records at Compact gaging stations have compiled with these
<br />regulations.
<br />
<br />The accuracy of discharge data depends primarily on (1) the
<br />stability of the stage-discharge relation, or if the control is un-
<br />stable, the frequency of discharge measurements', and (2) the accuracy
<br />of observations of stage, measurements of discharge, and interpre-
<br />tation of records.
<br />
<br />The station description states the degree of accuracy of the
<br />daily records. "Excellent" means that about 95 percent of the daily
<br />discharges are considered to be within 5 percent of true value;
<br />"good" within 10 percent; and "fair" within IS percent. "Poor"
<br />means that daily discharges have less than "fair" accuracy.
<br />
<br />The phrase "within 5% of true value" used to qualify "excellent"
<br />records establishes the extremes of the probable errors for 95% of
<br />the days in a given period of time. The word "within" defines the
<br />range of errors with individual daily values falling between 95%
<br />and 105% of true value. The probable error in a monthly or annual
<br />mean discharge depends more on the distribution of the daily errors
<br />between these two limits than it does on the limits themselves.
<br />For this reason monthly and annual records are much more accurate
<br />than most daily records.
<br />
<br />",it'~~"..".~,:...,..
<br />;;~~~~~~4~:::;~~(~i~~~
<br />;:'.~"Y..f,~~,..",-~t... .#....~'.t~~.-:~,;
<br />. '"", _ ~>~'!;~ _ ,,", 0::
<br />.'. ';'>""~~~ ~~... ~~.;~,.~
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />
<br />.,.~!.,.
<br />
<br />
|