This report embodies two principal objectives: 1) updating rainfall intensity-duration curves for the hydraulic design of culverts and 2) adaptation of the Stanford Watershed Model concept to small drainage basins in Kentucky. The first objective is familiar -- the curves presently being used for the rational method of design were established from an earlier Department study made by E. M. West and W. H. Sammons, issued in July, 1955 (Report No. 2, "A Study of Runoff from Small Drainage Areas and the Openings in Attendant Drainage Structures"), and were based on rainfall records then available through 1951. The second objective is somewhat more ambitious and more complex; in its most practical sense, it involves an attempt to equate total rainfall to total runoff and losses throughout a span of years; the losses are then accounted for as evaporation, infiltration, etc. Ideally, all of the significant hydrological parameters may be deduced; then through direct measurements of some essential input descriptors and indirect estimates of others, the water-balance concept may be applied to other basins.

Report Date


Report Number

No. 250

Digital Object Identifier



The opinions, findings, and conclusions in this report are not necessarily those of the Department of Highways or the Bureau of Public Roads.