Another item to consider is to make sure that you have a little bit of water in your detention basins. If you are using storage areas, set the initial elevation to 0.1 foot above the invert. If you are modeling the basins with cross sections, make sure you have a minimum flow in your flow...
I would think what you proposed should be sufficient for a CLOMR submittal. I think it would be important to account for what is providing an obstruction to flow. Be sure to provide a brief note in the cross section editor to explain what you are trying to represent and if possible, attach a...
In order to model the detention within HEC-RAS, you will need the hydrographs. I have successfully completed several detention analyses using unsteady flow HEC-RAS models.
As cvg said, it may be easier to just do your routing within the hydrology software than to set up an unsteady flow...
There is no tool for sloping blocked obstructions, just sloping abutments at bridges. A work-around could be to use the Multiple Blocks option and enter several, thin obstructions to simulates the sloping wingwall. It won't be perfect, but it may be a close enough approximation for your needs.
That is correct, HEC-RAS cross sections cannot cross one another. You can take the obstruction due to the wingwall into account using a the Blocked Obstruction option in the cross section editor.
Are you using an unsteady flow HEC-RAS model? That would be your best option. You could set up a plan for each storm event you would like to analyze. Then you would have to make several runs with different weir heights to determine which weir height meets your criteria. The program should...
I believe that you could use HEC-RAS to develop the rating curve you are looking for. I would recommend developing an unsteady flow model utilizing two storage areas (one for the lake and one for the river) connected with a river reach to model the breach. You could set up various model runs...
The level of effort for a LOMA and a LOMR-F can be vastly different. A single-lot LOMA can be applied for electronically in less than an hour. A LOMR-F will take more paperwork and coordination. So I wouldn't say there is a going rate, especially if you haven't done FEMA submittals previously.
KatieTX: Yes, I work in Houston at AECOM. Do we know each other?
KatiLynSki: I am glad that you were able to get your model to run. Sometimes, models with storage areas can be challenging.
There are two ways to approach this problem:
1) with your current model set up, add another river reach downstream of the downstream storage area. Add in some cross section. To model the outlet structure, put a culvert or inline weir in the downstream river reach.
2) Model the whole system...
