A comparative study of mean-section and mid-section methods for computation of discharge measurements

Abstract

In February, 1949, Mr. J. V. B. Wells, Chief of the Surface Water Branch, appointed a committee of three hydraulic engineers assigned to the Washington office to make a comparative study of the relative merits of the mean-section and mid-section methods of computing discharge measurements. this was done in order that there might be a basis for either adhering to the present "official" method, or adopting another method as the "official" one. This study is based on a collection of field data consisting of discharge measurements made with approximately four times the usual number of observations. There was a total of 213 of these special measurements made by all the district offices. The two methods of computation were examined as to accuracy and time savings. This was done by selecting observation stations from the special measurements to arrive at a synthetic measurement with the usual number of observations. This normal measurement was then computed by both the mean-section and mid-section method of computation for a comparison of results in discharge. A record was kept of the time consumed for computing and checking measurements so that any time savings in either method could be found. Much of the computation work was done in four of the district offices, with a variety in personnel as to grade and to experience in the use of the two methods.