Try the Urban Drainage UD-Inlet spreadsheet. It works for a lot of the common inlets and is based on HEC-22 methodology.
http://www.udfcd.org/downloads/software/UD-Inlet_v2.14b.zip
Wish I would have read this sooner. CheckRAS is a touchy program indeed.
The method mentioned on the website that you linked works best for me. If I get that message, I rerun the report with a generic type so that I get the message in CheckRAS that the report is the wrong type and then the...
I'm not familar with NYS criteria but shouldn't the very low imperviousness of the hillside offset the effect of the large area? The runoff for the hillside in the minor (water quality) event should be very small so the volume needed to be treated should be equally as small.
I normally do method 2 with an artifically increased travel time (higher mannings works).
I would be interested to find out the results of your two ideas. Please let us know what you determine. Thanks.
Sorry, I didn't see those Zone D areas. I looked too fast.
I am having trouble getting in contact with a friend over at FEMA Region 9. I will let you know when I do. By digital map, I meant the GIS data that was used to construct that DFIRM panel.
That map was revised effective Sept 30, 2005. Looks like a major update to DFIRM standards. There are no Zone D on that map any longer.
Use the link I provided above to generate your online Firm panel. Once you have the FIRM map follow the instructions to create a FIRMette of the location...
Can you post a copy of the FIRM panel where this is occuring? Have you used the FIRMette tool at FEMA's website?
http://msc.fema.gov/webapp/wcs/stores/servlet/CategoryDisplay?catalogId=10001&storeId=10001&categoryId=12001&langId=-1&userType=G&type=1
Agreed. We are working in floodplain area right now where the on-site detention standard is the 10-year storm event. If you can compare hydrographs it may not be necessary to detain up to the 100-year event.
The steady state model is virtually unchanged.
We have run a comparision between Hec-Ras 4.0 and Hec-6T and found that the one day simulation for bed change was quite different in locations.
We hope to give feedback to USACE soon.
FEMA can look at that detention pond as a levee under new standards. I common way to avoid the levee certification is to map the revised floodplain BFE within the pond. You would be suprised francesca on how much this is occuring in the US. Developments can be placed in the floodway fringe...
I find that the spreadsheets developed by Urban Drainage and Flood Control District are very useful for calculations at inlets.
You can go to their webpage and download UD-Inlet.
http://www.udfcd.org/downloads/down_technical.htm
Maybe this link will work also...
Can you post an image of the profile and cross sections at the bridge?
I have been dealing with a similar situation, but with about 3 feet of submergence over the roadway. What is your flooding depth? A few tenths?
My company renewed their license for Haestad's PondPack before I could let them know about HydroCAD. :(
PondPack input and output methods are terrible.
I use it very often doing floodplain work and open channel hydraulics. The software is very good and integrates well with AutoCAD. I do get bugs here and there since they just released RiverCAD XP last year, but when I do I send the information over to BOSS and they get back to me within the...
HEC-RAS can not model a split flow (lateral weir) and a bridge between the same two cross sections.
Any ideas on how to model a split flow situation over a roadway if there is a bridge also?
Any suggestions would be appreciated. Thanks!