(a) In
determining design storm flow magnitude, the applicant shall use an accepted
engineering method.
(b) For
drainage areas of less than 2 square miles the following methods are
acceptable, where appropriate:
(1) The
rational formula for flow magnitude determination when used according to the
following formula:
Q = CIA
Where C = the runoff coefficient
I = intensity of rainfall in inches per hour and
A = drainage area in acres.
To determine the proper intensity of rainfall for use with the
formula, first determine the appropriate total rainfall from "Technical Paper
Number 40, Rainfall Frequency Atlas of the United States, Department of
Commerce, May 1961," and the time of concentration from the Kirpich nomograph
and then obtain the intensity from the standard rainfall intensity-duration
curves;
(2) The SCS method
for estimating direct runoff, United States department of agriculture, soil
conservation service;
(3)
"Technical Release 55, Hydrology for Urban Areas, United States
Department of Agriculture, Soil Conservation Service."
(c) For drainage areas two square
miles or greater, the following methods of determining flow magnitude shall be
acceptable, where appropriate:
(1) the
publication "Magnitude and Frequency of Floods in Kansas, Unregulated Streams,
Technical Report 11, Kansas Water Resources Board, February
1975";
(2) "Technical Release 20,
Computer Program for Project Formulation, Hydrology, United States
Department of Agriculture, Soil Conservation Service"; or
(3) "HEC-1 Flood Hydrograph Package,
Corps of Engineers Hydrologic Engineering Center."
Notes
Kan. Admin. Regs. §
5-45-9
Authorized by and
implementing
K.S.A. 24-126; effective May 1, 1987.
