Consider this a listening post – I want to hear from you! Do the jurisdictions that review your stormwater submittals specify a specific software? or do they require a specific method? What, if you know, might get them to look at something new?
It would be great if you could post links here or start a list over at the Autodesk Civil 3D Stormwater Discussion Group. Let me hear from you!
Our office is the municipal engineer for many local towns so I do my own share of reviewing and most of the local towns/we accept most anything. Some output is definitely easier to follow than others. We even get chicken scratch hand calculations which I wish we wouldn’t accept but that is a different story.
When I am doing design work and have to get it approved by the State of CT DEP they will only accept models created in programs that are in the public domain and require the model to be provided on a CD so they can be recreated for review (ex. HEC-2, HEC-RAS, WSP2 and WSPRO are all acceptable models)
My experience is that the big cities have their preferences to tie into their own software such as XPSWMM or MOUSE. Generally that is because the cities retain their own consultant engineer instead of keeping engineers on the payroll to cut costs. In the small areas, the liability lies with the consultant in terms of stormwater storage, flow rates, etc, but some places have an internal calculation set up to check if storage is reasonable based on experience in the area.
So, I would assume interoperability is key. You have an interesting observation in that XPSWMM and MOUSE are proprietary software packages. I have seen a submittal rejected because I didn’t have a specific version that they accepted.
I find it a bit more common that agencies only accept the public domain models.
Here is GA we typically have to go by the Georgia Stormwater Manual http://www.georgiastormwater.com/ . While we are supposed to have a unified code and manual different jurisdictions have their views and querks. Mostly I’ve found that they don’t look at the stormwater as one system but instead two (pipes and ponds). Their is not mass balance on the system. My favorite is one county requiring you to run the pond completely full when running the pipes. It’s like running two 100 year storms.
In our region, it is the method that is important.
Our Office supports various software programs to achieve the same result, (based on individual preferences). Software programs are not used for final designs because the “output” is not preferred by the engineer who seals the drawing or the reviewing agency.
Our ordinance in Tippecanoe County, Indiana states in part:
On sites larger than 5 acres, runoff shall be determined by:
“…model that can generate hydrographs based on the NRCS TR-55 time of concentration and curve number calculation methodologies and the Huff Third Quartile (50%) Rainfall Distribution…. Including… TR-20, HEC-HMS and HEC-1. Other models may be used with the prior approval of the Tippecanoe County Drainage Board. Examples of other computer models that have been previously approved by the Tippecanoe County Drainage Board include PondPack, AdICPR, and XP-SWMM.”
So… I think we would have no problem getting most any software approved that is “reasonable and prudent”. Of course, there is the very odd requirement in our ordinance of finding the peak storm by modeling ALL storm durations (between 5 min and 24 hrs) using the Huff 3rd Quartile!