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The Parshall Measuring Flume

THE PARSHALL MEASURING FLUME 
A HISTORICAL LANDMARK 
OF 
AGRICULTURAL ENGINEERING 
SINCE THE BEGINNING OF IRRIGATED AGRICULTURE 
IT BEEN IMPORTANT TO MEASURE FLOWS OF IRRIGATION 
WATER. ACCURACY OF EARLY WATER MEASUREMENT METHOD 
OFTEN SUFFERED BECAUSE OF TRASH OR SEDIMENT IN THE 
WATER OR UNUSUAL FLOW CONDITIONS. 

RALPH L. PARSHALL SAW THIS PROBLEM WHEN HE BEGAN 
WORKING FOR THE USDA IN 1915, AS AN IRRIGATION RESEARCH 
ENGINEER. IN 1922 HE INVENTED THE FLUME NOW KNOWN BY 
HIS NAME. WHEN THIS FLUME IS PLACED IN A CHANNEL, FLOW 
IS UNIQUELY RELATED TO THE WATER DEPTH. BY 1953 PARSHALL 
HAD DEVELOPED THE DEPTH-FLOW RELATIONSHIPS FOR FLUMES 
WITH THROAT WIDTHS FROM 3 INCHES TO 50 FEET. 

THE PARSHALL FLUME HAS HAD A MAJOR INFLUENCE 
ON THE EQUITABLE DISTRIBUTION AND PROPER MANAGEMENT 
OF IRRIGATION WATER. THOUSANDS OF FLUMES HAVE BEEN 
USED TO MEASURE IRRIGATION WATER AS WELL AS INDUSTRIAL 
AND MUNICIPAL LIQUID FLOWS, THROUGHOUT THE WORLD. 

THIS PLAQUE MARKS THE SITE OF THE ORIGINAL COLORADO 
AGRICULTURAL COLLEGE HYDRAULICS LABORATORY, WHERE 
PARSHALL CARRIED OUT HIST HISTORIC EXPERIMENTS. 

DEDICATED 
BY THE 
AMERICAN SOCIETY OE AGRICULTURAL ENGINEERS 
1985


Submitted by @PraliteMonks

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