>>>> Warren Campbell wrote:"With regard to sheet flow length, McCuen recommends that the sheet flow length be given by L n/sqrt(S) = 100 ft. "

Interesting.

Actually, I have a handwritten note in my June 1986 copy of TR55 concerning the the computation of Tt (Eq. 3-3 on Page 3-3). The text says "For sheet flow of less than 300 feet, use Manning's kinematic solution..." The note, to be inserted between "300 feet" and "use," reads "or, more precisely, Tt less than or equal to 0.4 hours,"; as I recall this information was provided by the NRCS' former (?) state hydraulic engineer in Minnesota, Sonia Johnson.

Jeff Rice
jrice@urban-systems.com