Hello all,
I have been tasked with providing options for an expanding a small campus's water system. My previous experience with potable systems is for much larger operations, with 100k gal elevated reservoirs serving a population on the order of 6,000 people. This project is related to a...
I have an older hydrocad model that was built in v10, build 1. Recently I updated to the latest build, and when I ran the model, received this error on a pond with an exfiltration and culvert outlet. I don't recall getting this error before, when was this error added to the list?
Thanks, folks. There were a lot of tweaks I had to make from the standard values in the calc dialog box, so I probably missed something. Just wanted to make sure that was the issue, and not something on the back end.
Hello,
I am attempting to re-create a hydrocad model based on output reports. This original model was created in version 8.5, and I am using version 10.00 to build it. I have success in getting similar outputs for the subcatchment and reach nodes, but the pond node is behaving oddly, my...
not sure what the cost comparison is to chemical flocculant, but there are several vendors out there selling concrete structures with removable filter media cartridges, targeted at urban stormwater sites mostly. It may be worth looking at installing one of these in-line with the sediment pond's...
Hello all,
I have been asked to estimate the extent of groundwater level drawdown for a proposed swale (2' deep) that extends through a wetland (presumed groundwater elevation 6" below grade). The regulator is asking for an area around the swale that will have a lowered water table elevation...
I like your client's approach. If they wait until the next billing statement, previous fees magically go away!
Perhaps do what they ask and attach another statement with the remaining info on it? That way they get the piece of paper they want AND the piece of paper that gives the full story...
Hello,
I have worked with the simple method model for determining annual pollutant load in the past. Now I'm tasked with doing it again, but I was given this source for the model formula:
http://des.nh.gov/organization/divisions/water/stormwater/documents/wd-08-20a_ch8.pdf
formula is on the...
Hello all,
I am working on a storm facility located in sandy soils, so I plan to use infiltration practices. One of the design criteria is the detention of a 1-year storm event over a 12 hour period.
When modeling my pond without infiltration, I can size a control orifice that provides the 12...
This is for a wet pond, so there will be some inflow held in the basin. I take it that means that 34% of my flow becomes the replaced volume of my permanent pool?
In my state, the regulators typically look at the COM detention time to determine if their criteria are being met. In the model I'm working on now, the plug flow time is nearly double the COM time. Reviewing HydroCAD's website entry on the difference between the two, I believe that using COM...
I am looking at the new feature that provides the pollutant loading for subcatchment areas. IN the reports, it appears that the results give a quantity of pollutant per storm event. Is there a way to get an annual pollutant loading number from this new feature?
Thanks,
- shane
Hello,
I am re-permitting a gravel pit and working on a noise model. Unfortunately, the crusher is inoperative at the moment and I cannot directly measure noise levels. Does anyone have information on 'typical' crusher noise levels that I could use to plug into a noise attenuation model...
NEBB is the National Environmental Balancing Bureau (www.nebb.org)
According to the specs we have read, vibration measurements are to be taken at various points on the pump housing, base, piping and floor. It can be determined in 1/3 octave bands or in 1 Hz increments from 1 - 200 Hz.
Our firm is looking into offering vibration testing for the commissioning of buildings. We have reviewed the materials at the NEBB website and have a decent handle on what goes into the testing procedure. Now we are looking to rent a meter to do some dry runs.
Does anyone here have...
Hello,
I am starting the environmental/permitting work for a sand & gravel operation. I'm looking for safety regulations for pits (e.g. max cut slopes, design of benching, min tree clearing width at top of slope, etc.) on the MSHA website, but quickly got lost. Anyone have a link to this type...
I was enjoying the back-and-forth between you two. Thanks for the open discussion, it's an educational experience. Maybe I should change my handle, since I do more stormwater/site layout than chemical engineering now. However, I have not done dam/embankment design, and I know that it is a...
Thanks for the responses. Here's a bit more detail.
The structure is pretty small. The dam impounds about 6 ac-ft, which puts us well under our state's jurisdictional threshold (12 ac-ft).
The pond is an existing farm pond that failed in the past (right now the location of the embankment is...
Hello,
I am working on the design of a culvert that serves as the primary outlet of a stream-fed pond. I have sized the structure as an 83" x 57" pipe arch. 100-yr storm flow is 163 cfs, and the pond rises 3.25' during the storm. The embankment of the pond is about 10' tall at its highest...
Thanks for the reply. I took out the diversion structure and it helped a bit, though I still have overflow issues. The inflow out is bigger than the inflow in; and while the inflow is able to be handled by my overflow culvert, the bigger outflow is not. Here's the HCAD file that spells it...
