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|Title:||Comparison of flood for various return periods estimated using L-moments & other conventional techniques|
Sapra, Tilak Raj
|Abstract:||Information on flood magnitudes and their frequencies is needed for design of various types of water resources projects/ hydraulic structures such as dams, spillways, road and railway bridges, culverts, urban drainage systems as well as for taking up various non-structural measures such as flood plain zoning, economic evaluation of flood protection projects etc. Since scientific hydrology began in the seventeenth century, one of the most difficult problems facing engineers and hydrologists is how to predict flow in basins with no records. Whenever rainfall or river flow records are not available at or near the site of interest, it is difficult for hydrologists or engineers to derive reliable design flood estimates directly. In such a situation, regional flood frequency relationships developed for the region are one of the alternative methods for prediction of design floods, especially for small to medium size catchments. Considering the importance of prediction in ungauged catchments, the International Association of Hydrological Sciences (IAHS) launched "Prediction of Ungauged Basins (PUBs)" as one of its initiatives and declared the current decade as "Decade of PUBs". As per the Bureau of Indian Standards (BIS) hydrologic design criteria, frequency based floods find their applications in estimation of design floods for almost all the types of hydraulic structures viz. small size dams, barrages, weirs, road and railway bridges, cross drainage structures, flood control structures etc., excluding large and intermediate size dams. For design of large and intermediate size dams probable maximum flood and standard project flood are adopted, respectively. Most of the small size catchments are ungauged or sparsely gauged. To overcome the problems of prediction of floods of various return periods for ungauged and sparsely gauged catchments, a robust procedure of regional flood frequency estimation is required to be developed. In this study, floods of various return periods have been estimated using L-moments, least squares based EVI distribution and PT III distribution methods for a snow and rainfed area. Result obtained from the analyses of the various approaches have been compared.|
|ISSN:||0975-2412 (Online); 0771-7706 (Print)|
|Appears in Collections:||BVAAP Vol.20(1) [June 2012]|
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