You can model this situation in HydroCAD and similar programs. I would treat the grate as a horizontal orifice which you can set the opening percentage. You know the discharge pipe and you can figure out how much flow is getting to the low point. Separately, i know local foundries in our area...
Hello,
I am designing a sediment basin in NJ. The basin design includes a riser pipe (currently shown as 24" diameter, and the discharge coefficient selected is 0.60. We need to get the maximum water surface elevation to come down and i was considering designing an anti-vortext device on top...
thank you for your response peter. i have eliminated an error that seems to have fixed the issue. This has caused another issue to deal with, but that is unrelated to HydroCAD! Again, thank you.
I have a situation where the peak flow OUT is calculated to be slightly larger than the flow IN.
Logically, i'm not sure i can think of a scenario where this makes sense... I've tried finer routing, and several different types of minor adjustments but cannot change the situation.
The township...
Hello All,
Hoping you might be of assistance. I have designed an infiltration basin in HydroCAD.
For the "Exfiltration" Outlet, i have selected the "Conductivity" type as we have a known conductivity of 17.25 inches per hour. Previously, the basin bottom was 2.5 feet above the groundwater...
Hello,
We usually do not get involved with mounding analysis for our infiltration basin designs - unless required by the reviewing engineer.
Our NJ state requirement for infiltration basins is to have a 2 foot separation to groundwater, and to "halve" the percolation rates of the soil for the...
Hi all,
Got into a debate with a municipal review engineer about roughness coefficients for Lawn area.
I do most of my stormwater calculations using the HYDROCAD program. The typical list of values for grass manning's coefficients is:
Short grass prairie - 0.15
Dense grasses...
For years, i have used Hec-Ras to produce flood elevations for streams including those that have culverts. I simply model the culvert in Hec-Ras.
I have just recently come across a project where a very renowned civil engineer received an approval from our state's DEP (NJ) by treating the stream...
Good morning all!
I have a situation where a drainage area flows towards and existing inlet with a 10" pipe discharge.
I setup hydrocad to show that the 10" pipe is the primary discharge, the parking around around the inlet is a small "pond" with a weir created which represents the low point...
thank you for the very thorough response Mike!
i am convinced that "Thrie" is the correct term, however back to the original problem - we simply ended up calling the detail "Guiderail Detail" or something similar to avoid the issue entirely (even though we were correct). It wasn't worth the...
Using HydroCAD to prepare calculations to meet NJ state groundwater recharge requirements (infiltration of the increase in 2 year storm runoff volumes).
After applying the design infiltration/conductivity rates, where can i view how much total water has been infiltrated? The summaries indicate...
thank you all for you great responses.
fel3, yes - our state DEP requires us to EXCLUDE infiltration for the very same worst case/ no maintenance scenario.
Regarding the soils in general, like everything else on this project, the applicant has reached the bare minimum. These swales have no...
Thanks PSMART. So basically the engineer uses a formula that is 0.5 * Q * TC * (60 sec/min) to arrive at an answer in cubic feet. Which i assume is supposed to represent the volume under a triangle with TC on the X axis, and Q on the y axis. They previously calculated Q using the rational...
Hello All:
My company has to review a site plan for a small 10 unit towhhome development. So I’m reviewing the plan and almost everything on the job is tight, but meets the ordinance requirements. The only real concern I have is with respect to stormwater.
The site is about an acre. The...
can someone please explain where the term "Thrie" comes from?
for years I thought this was a spelling mistake of the word "three" but my state's approved guiderail is called "Thrie". A local reviewer commented on my latest plan set saying that I needed to correct this spelling mistake. I'd...
ha, i also had cross-sections where bringing the stations closer to one another made the WSE get lower... bizarre! Since my last post, i have submitted our model for permitting. AsiIt turns out our state DEP reviewer does not accept the fact that HEC RAS might not be perfect, and is giving me...
froude,
i painstakingly am doing the encroachments using method 1, one by one, moving from upstream to downstream, careful so that i do not upset the water surface for the upstream cross-sections. Thanks, this seems like the only way. what a pain!
andy
