We are proposing to use concrete box culverts for inline detention beneath the streets. Does anyone know of a product or method of closing off/sealing the upstream ends of the boxes? I found a company in Canada that manufactures plugs, but they only deal in metric sizes. I've been unable to get...
I've been given an assignment to model 2- and 100-year storms for a 70-acre site using EPASWMM. Previously, the local jurisdiction wasn't particular about what software was used on a project, but for some reason they are requiring SWMMM for this one. We have the appropriate IDF curves and...
Simple question: Are wye fittings ever used on water mains? I'm used to seeing tees where a water line connects with another one, but I have a set of drawings in front of me on which the engineer is showing a lot of, what I consider unnecessary, wyes. The water mains are primarily 8" and 12".
We designed an underground detention system using 30" HDPE pipe. According to our details and ASTM 2321 the trench is supposed to have a minimum clearance between the pipe and the trench wall of 10", backfilled with compacted Class I or II material. The contractor instead set the pipe in a...
A parking lot we designed was recently completed. Visual inspection revealed areas with what appears to be fine, loose asphalt on the surface. Core density reports done on the pavement showed compaction below what was specified in 14 of 16 samples. Twelve of the samples show a core depth more...
The City's new guidelines state that on roadway projects the starting tailwater elevation for extreme event analysis should be the 10-year water surface elevation at the outfall. If the project location is a considerable distance from the outfall channel, the 10-year WSE can be assumed to be 48%...
The City has a set of IDF curves covering rainfall frequencies from two years through 100 years. However, the LEED SS6.1 template asks for 1- and 2-year runoff amounts.
Is there a way to generate b, d, and e coefficients for a 1-year frequency if 2-, 3-, 5, 10, 25, and 100-year coefficients are...
Can someone give me an equation I can plug into excell to calculate the volume/capacity of an irregular shaped detention pond with sloped sides, assuming the top and bottom areas are known?
The Interlocking Concrete Paver Institute has a specification for permeable pavers that states that the stone aggregate beneath the pavers must be washed, with no more than 1% passing a No. 200 seive. The stone must be compacted to 95% of the labratory index density established for the stone...
My client wants to avoid the cost of building a traditional cantilever retaining wall with a footing, etc. He is asking that we build it onto the edge of an existing concrete driveway. The wall will be 2.5 feet high at most if constructed in that manner.
The pavement is 6 inches thick, which...
We recently had a clean and television inspection (CTV) done on sanitary sewers in a large neighborhood. The CTV mechanism shoots a water jet ahead of the camera to clean out debris so you can assess the condition of the pipe.
Even after the water jet there were still pipe segments with heavy...
The contractor is trying to proofroll the soil on a road construction project. They have discovered that water is migrating into the area from an adjacent undeveloped area. This is preventing the soil from drying sufficiently for them to proofroll.
Geotechnical borings prior to completion of...
We will be using reclaimed/recycled asphalt base in a parking lot. The question was asked if ASTM D698 would be appropriate for testing the compaction. If not, can someone tell what the appropriate specification would be?
Thanks in advance.
I am trying to size a restrictor pipe for a detention pond using the orifice equation Q=CA*sqrt(2gh). I have run into a wide range of interpretations as to what head is being represented by the "h" in the equation. The restrictor pipe will be five feet long, and sit inside the outfall pipe from...
If the bottom of a proposed retention pond/water feature will be below the water table, are there any factors, environmental or otherwise, that would require (or preclude) the use of a clay liner or similar product to separate the pond water from the groundwater?
We plan on using City water to...
I need to design a temporary parking lot using a permeable material on top of a crushed stone bed. I am using underdrains since the subgrade is clay, and there will be virtually no infiltration.
My question is, how do I calculate the velocity or volume of water passing through the stone...
Is there a resource (chart, spreadsheet, code, etc.) that I can access to determine the correct size of a domestic water meter if the daily and peak flows are known?
LEEDS Credit No. 6.2 gives one point for storm water quality on a project seeking LEEDS certification. One requirement is that the design must capture and treat 90% of the annual rainfall. Most storm water quality management units on the market are designed to treat the first flush only, with...
I specified that an 8" perforated pipe wrapped in filter fabric and backfilled with gravel (18" cover) be placed beneath a playground covered with wood chips. The architect wants to use styrofoam packing peanuts in lieu of gravel backfill. Does anyone have experience using this material for...
