THE MASTER PLANNING DIVISION OF THE WATER AND POWER DEVELOPMENT AUTHORITY (WAPDA), GOVERNMENT OF PAKISTAN, HAS BEEN CONDUCTING WATERCOURS SURVEYS THROUGHOUT PAKISTAN IN THE LAST FEW YEARS. A BASIC DATA COMPONENT OF THIS SAMPLE SURVEY IS THE USE OF CUTTHROAT FLUMES FOR MEASURING FLOWS AND WATER LOSSES IN EACH OF THE 61 WATERCOURSES INCLUDED IN THE SURVEY. THE THREE CUTTHROAT FLUME SIZES ARE 8" X 18", 8" X 36", AND 12" X 36", WHERE THE FIRST DIMENSION IS THE THROAT WIDTH AND THE LAST DIMENSION IS THE FLUME LENGTH. THE RECALIBRATION WORK PERFORMED IN THE LABORATORY FOR THESE FLUMES, ALONG WITH REFINEMENT OF THE DATA ANALYSES, WOULD INDICATE THAT THE FREE FLOW RATINGS FOR THE 8" X 18" CUTTHROAT FLUME WOULD BE REDUCED 3 PERCENT, THE FREE FLOW RATING FOR THE 8" X 36" CUTTHROAT FLUME WOULD BE REDUCED 1.3 PERCENT, AND THE FREE FLOW RATING FOR THE 12" X 36" CUTTHROAT FLUME WOULD BE REDUCED 2 PERCENT. LABORATORY STUDIES HAVE SHOWN THAT THE 8" X 18" CUTTHROAT FLUME IS AFFECTED BY ENTRANCE CONDITIONS. CONSEQUENTLY, THE USE OF THREE PIEZOMETER TAPS AT BOTH HA AND HB, COMPARED WITH USING A SINGLE TAP CONNECTED TO EACH STILLING WELL, HAS A SIGNIFICANT IMPACT UPON THE FREE FLOW AND SUBMERGED FLOW RATING.