ANALYSIS OF HYDROLOGIC DATA USING PEARSON TYPE III DISTRIBUTION.

Abstract

Peak flow magnitudes relating to 16 streams were utilised for deriving long term estimates using Maximum likelihood method. The results revealed that most of peak flows were underestimated and their departures from the respective prototype magnitudes were of the order of 10 to 40 per cent. These peak flow magnitudes were graduated by the Pearson type III distribution with the result that a perfect calibration (departure within 1 per cent only) was achieved for three streams. For remaining streams the departures were reduced and were within 20 per cent. The precision of the estimates, deduced from the use of the Pearson type III distribution, was ascertained by evaluating the confidence intervals for these estimates.