Kansas Administrative Regulations
Agency 5 - DEPARTMENT OF AGRICULTURE-DIVISION OF WATER RESOURCES
Article 40 - DESIGN OF EARTH DAMS
Section 5-40-30 - Time of concentration
Current through Register Vol. 43, No. 39, September 26, 2024
(a) Except as specified in subsections (b) and (c), the time of concentration (Tc) shall be determined by using one of the methods specified in chapter 15, "travel time, time of concentration and lag," in the natural resources conservation service (NRCS) national engineering handbook, part 630, dated August 1972, which is hereby adopted by reference.
(b) For drainage areas of not more than three square miles, the time of concentration (Tc) may be determined by use of the Kirpich formula, which is as follows:
See Equation at http://www.kssos.org/pubs/register%5C2007%5CVol_26_No_18_May_3_2007_p_607-676.pdf
Where
Tc = the time of concentration, in hours
L = the longest distance that water has to travel in the drainage basin, in miles
H = the maximum elevation difference in the drainage basin, in feet.
(c) In addition to the methods specified in subsections (a) and (b), the applicant may determine Tc based on sound engineering principles and commonly accepted engineering practices if the applicant obtains the prior written consent of the chief engineer.
