JOINT PROBABILITIES IN THE RAINFALL-RUNOFF RELATION
A PROBLEM IN SURFACE DRAINAGE OF HIGHWAY IS THE ASSIGNING OF PROBABILITIES TO PEAK RATES AND TOTAL VOLUMES OF RUNOFF, PREDICTED FROM RAINFALL WITH KNOWN PROBABILITY OF OCCURRENCE. AN ATTEMPT TO SOLVE THIS PROBLEM WAS MADE THROUGH CONSIDERING THE RAINFALL ON A CATCHMENT AND THE MOISTURE STATUS OF THE CATCHMENT AS STOCHASTIC VARIABLES. PROBILITY DISTRIBUTIONS WERE DERIVED FOR THESE STOCHASTIC VARIABLES. BY A RANDOM SAMPLING TECHNIQUE USING THE PROBABILITY DISTRIBUTIONS, IT WAS POSSIBLE TO DEFINE INPUT AND INITIAL CONDITIONS FOR A PROBABLE FLOOD EVENT. A DETERMINISTIC WATER BUDGET APPROACH MAKES IT POSSIBLE TO TRANSLATE THE RAINFALL INPUT INTO A RUNOFF HYDROGRAPH. IN THIS WAY, SERIES OF PROBABLE FLOODS CAN BE GENERATED. ANALYSIS OF THESE SERIES OF GENERATED FLOODS PERMITS ASSIGNING PROBABILITIES TO THE MOST PROBABLE CORRESPONDING FLOODS. IT WAS POSSIBLE TO DESCRIBE THE TIME PATTERN OF RAINFALL INTENSITY BY MEANS OF THE INCOMPLETE BETA-FUNCTION. THE TWO-PARAMETER LOG-NORMAL DISTRIBUTION FUNCTION WAS A SUITABLE DESCRIPTOR FOR ALL THE NECESSARY PROBABILITY DISTRIBUTIONS. THE RESULTS OF THIS EXPLORATORY INVESTIGATION WERE TESTED AGAINST ANNUAL SERIES OF OBSERVED FLOOD PEAKS ON TWO VERY SMALL RURAL CATCHMENTS. RESULTS ARE POSITIVE AND PROMISING. /AUTHOR/
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Supplemental Notes:
- Paper sponsored by Committee on Surface Drainage of Highways and presented at the 48th Annual Meeting. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
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Authors:
- Hiemstra, Lourens A V
- Publication Date: 1969
Media Info
- Media Type: Digital/other
- Features: Figures; References; Tables;
- Pagination: pp 1-17
- Monograph Title: Surface drainage of highways
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Serial:
- Highway Research Record
- Issue Number: 261
- Publisher: Highway Research Board
Subject/Index Terms
- TRT Terms: Drainage basins; Floods; Hydrographs; Normal distributions; Probability theory; Rainfall; Randomization; Runoff; Stochastic processes; Surface drainage
- Uncontrolled Terms: Flood peaks
- Old TRIS Terms: Highway drainage
- Subject Areas: Data and Information Technology; Highways; Hydraulics and Hydrology;
Filing Info
- Accession Number: 00204218
- Record Type: Publication
- Files: TRIS, TRB
- Created Date: Aug 4 1994 12:00AM