Laserfiche WebLink
Worksheet 3: Time of concentration iTc) or travel time (Tt) <br />• <br />• <br />C I <br />Project SDHR1 ~ "C" By ~- Dace 7/7/93 <br />Location Checked Date <br />Circle one: Present Developed <br />Circle one: Tc ~Ttlchrough subarea <br />NOTES: Space for as many as tvo segments per flow type can be used for ea eh <br />vorksheet. <br />Include a map, schematic, or description of flov segments. <br />Sheet floe (Applicable to Tc only) Segment ID <br />1. Surface description (cable 3-I) ............ <br />2. Nanning's roughness coeff., n (cable 3-l) .. <br />3. Flov length, L (total L C 300 fc) .......... ft <br />4. iwo-yr 24-hr rainfall, P2 .................. in <br />5. Land slope, a .............................. ft/ft <br />6. Tt 0.00075(nOL)~'8 Compute Tt ...... hr <br />P2 s <br />Shallow concentrated flow Segment ID <br />7. Surface description (paved or unpaved) ..... <br />8. Flow length, L ............................. ft <br />9. Watercourse slope, s ....................... ft/fc <br />!0. Average velocity, V (figure 3-1) ........... ft/s <br />11. Tt 3600 V Compute Tt ...... hr <br />Channel flow Segment ID <br />12. Cross sectional flow area, a ............... ft2 <br />13. Petted perimeter, pw ....................... ft <br />14. Hydraulic radius, r ~ Pa Compute r ....... ft <br />v <br />15. Channel slope, s ........................... ft/ft <br />16. Hanning's roughness coeff., n .............. <br />2/3 1/2 <br />17. V 1.49 rn a Compute V ......, ft/e <br />18. Flow length, L ............................. ft <br />19. Tt 3600 V Compute Tt ,,,,,, hr <br />20. Watershed or subarea Tc or Tt (add Tt in steps 6, 1 <br />1, end 19) ....... hx <br />42-8 <br />(210-VI•TR-56, Second Ed., June 1986) <br />0.02 <br /> <br />0.02 <br />D•3 <br />