keroberozz
Civil/Environmental
- Feb 21, 2006
- 1
I used HEC-RAS and tried to reduce “Profile Delta WS” down to be no more than 1’ according to FEMA. First, I tried with Method 4 with Target Value of 1’. I did change the target values (Target WS change) many times and run the program based upon the criteria on the manual that the target values of such station have to be adjusted to the target values of the PF of that station that has Profile Delta WS closet to one but no more than one for all PF in that station.
My PF1, PF2 and PF 3 are 2, 10 and 100 year respectively. I first try target value of 0.8 and 0.9 for PF2 and 3 respectively. The result of PF3 has Profile Delta WS more than 1’. The target value with the closet Profile Delta WS closet to one but less than one is PF2. Accordingly, I went back and adjust that station target value to 0.8 for the entire station. However, the Profile Delta WS are still higher than one. I kept adjusting the target value though it never work no matter how many times I tried. Also, I understand that I should use Method 1 to finalize the floodplain one more time though I still get stuck with this 1’ Target depth that has to be performed by Method 4 first. Please advice. Thank you very much.
My PF1, PF2 and PF 3 are 2, 10 and 100 year respectively. I first try target value of 0.8 and 0.9 for PF2 and 3 respectively. The result of PF3 has Profile Delta WS more than 1’. The target value with the closet Profile Delta WS closet to one but less than one is PF2. Accordingly, I went back and adjust that station target value to 0.8 for the entire station. However, the Profile Delta WS are still higher than one. I kept adjusting the target value though it never work no matter how many times I tried. Also, I understand that I should use Method 1 to finalize the floodplain one more time though I still get stuck with this 1’ Target depth that has to be performed by Method 4 first. Please advice. Thank you very much.