No-Rise Certification Question
No-Rise Certification Question
(OP)
I have a client who is planning to add on to his dock. The property is located in Northampton County, NC. The addition will include 4 – 4x4 posts to be in constructed in the lake. The county is requiring that our client get a No-Rise Certification before they issue a building permit. Are there any guidelines/methods for correctly modeling the effect of the dock posts in the lake and floodway? Any guidance would be appreciated.





RE: No-Rise Certification Question
RE: No-Rise Certification Question
RE: No-Rise Certification Question
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com
RE: No-Rise Certification Question
RE: No-Rise Certification Question
RE: No-Rise Certification Question
I don't have much exertise in this area, however just trying to rationalize the request. I look forward to see other posts from the forum.
RE: No-Rise Certification Question
The only way a bureaucrat can lose his job is if he actually makes a judgment call. That's just the nature of the regulatory environment. Following the rules ad-absurdum not only ensures you don't lose your job, it positions you well for promotion. I suspect you have run into one of these people. They're quite common, in truth.
So the natural thing to do is to rant and rave about how stupid their request is, but the better thing to do is try to see the issue from their point of view. They're a bureaucrat looking after their job security, so they want you to provide them some sort of documentation they can point to that shows they followed the "no rise rules" in your design review.
So here's what I would do. First I'd try to get a hold of the hydrology study for the lake, presuming there was one. That study probably had a stage storage table in it somewhere, just subtract the volume of the posts from the lake storage, show the reviewer that the stage storage didn't change due to roundoff error, and submit a 'compliance study' with them that acts as an amendment to the approved hydro study on file. If such a study doesn't exist, then compensate for the volume of the posts by digging a few wheelbarrows full of dirt out of the shore somewhere to compensate.
If the reviewer wants HEC-RAS for this, then make a painstakingly detailed effort to explain to your client how unreasonable the reviewer is being and ask him what approach he'd like to take. If it gets that far, then it might not be an engineering issue at all. The whole thing could be political, and may need to involve his boss.
The two most likely scenarios I see are either A) you ran unto Ultimate Bureaucrat and just need to work it out with him somehow, or B) the owner pissed off local government and the issue isn't the dock at all, it's something else.
This sort of thing is what makes engineering fun, right? :)
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com
RE: No-Rise Certification Question
RE: No-Rise Certification Question
Talk to the reviewer, try to handle this with a conformance letter, or an addendum to whatever hydrology study was performed for the lake, based on volume. Avoid HEC-RAS if possible.
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com
RE: No-Rise Certification Question
In %.
That could be a killer.
RE: No-Rise Certification Question
RE: No-Rise Certification Question
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com
RE: No-Rise Certification Question
RE: No-Rise Certification Question
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com
RE: No-Rise Certification Question
4 4x4 posts in a reservoir...
Is there something else we should konow?
RE: No-Rise Certification Question
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com
RE: No-Rise Certification Question
I do have a question concerning HEC-Ras. I have little experience with the software but upon looking at it the information for the dock would be input into the pier tab on the bridge scour window, correct?
RE: No-Rise Certification Question
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com
RE: No-Rise Certification Question
In the Geometric Data/bridge Culvert Data, you add the dock as a bridge deck/roadway between 2 cross sections and then you add piers.
RE: No-Rise Certification Question
Boundary conditions and flow rate.
RE: No-Rise Certification Question
Another option to consider.....just my two cents but I wonder if it's worh speaking to someone higher up the ladder to see if this is really necessary. Is it the engineer or the planner that is requesting the no-rise? I'm all for doing things the right way but for something like this I would wonder if a "no-rise" calculation would be required for boats entering the lake and or swimmers. By comparison, I would think that even a 14' aluminum boat would displace more water than 4-4x4 posts.
Again, just my two cents, but I think this request from the planner is unreasonable. For a creek it may be worth a look into but not a reservior.
RE: No-Rise Certification Question
This sounds to me like a reviewer who doesn't fully understand the science trying to cover his rear, and he probably just needs something to stick in his file that says the words "No Rise" on it with some math somewhere and a PE stamp. Just explain that there's no flow in the lake, and the volume change is minimal. For the 'math' portion of the conformance letter, show him a pre/post stage storage table.
If you do happen to run into an existing HEC-RAS model for this river, and it has the lake right there smack dab in the middle of the reach, please post it here. I'd like to take a look at it.
Hydrology, Drainage Analysis, Flood Studies, and Complex Stormwater Litigation for Atlanta and the South East - http://www.campbellcivil.com
RE: No-Rise Certification Question