WEIR DETAIL??
WEIR DETAIL??
(OP)
Does anyone know where I can find a concrete overflow structure (weir) detail for a retention pond? The local municipality is looking for something more permanent than a "grass"-type weir. My weir opening length is about 50' wide and top of bank is about 1.2' above bottom of weir elevation (ponding depth about 9"). Any help would be appreciated.





RE: WEIR DETAIL??
or fabric bags which are relatively inexpensive to install.You can use a variety of different materials and designs. You really have to decide what you need or what the city requires.
RE: WEIR DETAIL??
RE: WEIR DETAIL??
RE: WEIR DETAIL??
For a vertical weir, which is what is sounds like your detail is for, I would have a structural engineer look at it if possible, especially for the length you mention - a 45-ft long weir wall would need a foundation design and hydrostatic forces accounted for.
For a concrete lined spillway crest on a pond berm, i.e. a broad-crested overflow weir, consider if you can adapt a concrete slab detail like a driveway approach (in terms of thickness and reinforcing bar spacing/diam.), but add a vertical cutoff lip or alternative barrier to prevent any piping through the bedding material.
RE: WEIR DETAIL??
RE: WEIR DETAIL??
Just a thought I figured that I would mention.
RE: WEIR DETAIL??
Please see FAQ731-376 for great suggestions on how to make the best use of Eng-Tips Fora. See FAQ158-922 for recommendations regarding the question, "How Do You Evaluate Fill Settlement Beneath Structures?"
RE: WEIR DETAIL??
the local municipality is requesting a concrete lined overflow weir (broad-crested overflow weir) in lieu of the vertical-type weir. Has anyone had experience in a design of this type (i.e. slab thickness, rebar spacing, etc.)
thanks
RE: WEIR DETAIL??
Download at the following website (2004 english uniform standard Details for Public Works Construction):
http://www.mag.maricopa.gov/publications.cms
RE: WEIR DETAIL??
By vertical cutoff lip I mean a downward vertical extension (say 18-24 inches) integrated with the concrete-pour to prevent water from seeping/piping beneath concrete slabs used to construct a spillway. Actively design to prevent hydraulic piping through the bedding material, if any, beneath the concrete...
RE: WEIR DETAIL??
The weirs are relatively large (could be ideal for kids and skateboards). I've seen surfaces that look "bubbled" with concrete but this may change the weir coefficent and as a result increase the weir dimensions (and add more concrete). Any ideas/details/suggestions (i.e. weir speed bump???)?
Thanks
RE: WEIR DETAIL??
RE: WEIR DETAIL??
My personal opinion (I am not a lawyer, owner should consider legal ramifications): Sign it or fence it
Soap-box speech:
If the pond is a risk, fence it off for everyone, otherwise dont' worry about the boarders. Put up a sign about risks if that is the concern, something you should do anyways if the facility is unfenced. Skateboarding is not a crime (at least shouldn't be; there are much worse things kids can get into.... a really creative design for a mixed use stormwater facility could incorporate some cool skating features for when the facility is dry). Why single out skaters, what about people walking their dogs, or mountain bikers...... if skaters in the neighborhood are also hell-raisers there are already likely to be laws/ordinances to control nuisance behavior/graffitti/vandalism/etc.
Please let us know what you decide.