Abstract:
SINCE THE HYDROLOGIC PROBLEMS IN PLANNING HIGHWAY DRAINAGE ARE SIMILAR TO THOSE ENCOUNTERED IN MANY PHASES OF SOIL AND WATER CONSERVATION, HIGHWAY ENGINEERS MAY BE INTERESTED IN THE EXPERIENCE OF CONSERVATIONISTS. CLEARER UNDERSTANDING OF THE PROBLEM AND INFORMATION ON SOILS, PHYSIOGRAPHY AND LAND USE MADE POSSIBLE DELINEATION OF AREAS IN WHICH RESULTS FROM THE RUNOFF STUDIES ARE APPLICABLE. THROUGH PROBABILITY ANALYSIS OF THE RUNOFF RECORDS, DESIGN CURVES WERE DEVELOPED FOR SEVERAL AREAS OF APPLICATION. SAMPLES OF SUCH CURVES SHOW VARIATION OF PEAK RATES OF RUNOFF WITH SOILS, VEGETAL COVER, AS WELL AS RAINFALL INTENSITIES AND OTHER CLIMATIC FACTORS IN VARIOUS GEOGRAPHIC LOCATIONS. THE SHAPES OF THE SEVERAL CURVES EXPRESS THE RELATION OF PEAK RATES OF RUNOFF TO SIZE OF DRAINAGE AREA IN VARIOUS PHYSIOGRAPHIC PROVINCES. SOME OF THE CURVES HAVE ALREADY BEEN PUBLISHED. REPORTS CONTAINING OTHERS ARE IN VARIOUS STATES OF COMPLETION. ALL ARE SUBJECT TO REVISION IN THE LIGHT OF LONGER RECORDS AND RECORDS FROM WATERSHEDS OF VARIOUS SIZES IN EACH AREA OF APPLICATION. MANY ADDITIONAL RECORDS ARE REQUIRED TO VERIFY THE RESULTS AND TO DEVELOP SIMILAR INFORMATION FOR THE REMAINDER OF THE UNTED STATES. IF THIS NEW APPROACH IS ACCEPTED, ADDITIONAL RECORDS FROM SMALL WATERSHEDS CAN BE OBTAINED WITH A MINIMUM OF EFFORT AND EXPENSE. WITH PUBLISHED INFORMATION, MOST OF IT RECENT, ON THE HYDRAULICS OF CULVERTS AND ON DISCHARGE COEFFICIENTS OF NOTCHES AND INLET STRUCTURES, RECORDS OF PEAK RATE OF RUNOFF CAN BE OBTAINED BY A LIMITED NUMBER OF STAGE READINGS ON PROPERLY INSTALLED STAFF GAGES. BOX CULVERTS AND EVEN STREAMS SPANNED BY SMALL BRIDGES CAN BE RATED WITH THE "VELOCITY-HEAD ROD" WHICH, WHILE VERY MUCH SIMPLER, IS MORE SUITABLE FOR THE PURPOSE THAN THE CURRENT METER METHOD. A LIST OF 31 REFERENCES, DEALING WITH VARIOUS PHASES OF THIS SUBJECT, COMPLETES THIS PAPER. /AUTHOR/
Supplemental Notes:
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