Search results for query: *

I typically assume a flowing full condition when setting the slopes of the sewer. In reality, it may be hard to ge a full 3 fps. This is usually the case in the upstream pipes that may have a small tributary area but are being installed to pick up a designed low spot. I never use less than a 12"...

I can only release 0.15 cfs/acre. I am already at that in my design.

I am designing a wetland style pond and need to keep the total water inundation time under 72 hours during a 100 year event in order to not kill the plants. The site is about 10 acres and the pond is only about 2-2.5' deep. Using TR-20 with a Huff rainfall distribution, my total time is over 80...

Thanks for all your responses

I am designing a parking lot and the contractor wants to use recycled asphalt. What are the negatives to using this? I assume that the parking lot may not last as long but are their any other concerns? If it matters, I live in the midwest with some pretty cold winters.

Same rules apply unless you are using a water main quality pipe

Sewer and Water are ussually 10' hor. and 1.5' vertically

I don't think any plan on the internet will answer all your questions. Every site is different.

The first time it will be offered is this April. No one will have taken it yet.

I have read that the Time Interval needs to be less than 20% the time to peak. Is this correct? If so, I assume that means 20% of the time to peak of the Unit Hydrograph. Can anyone confirm my statement?

Well, I agree with the constraints that you mentioned. However, I feel that it is good in estimating the required volume that you will need. After that you can design your pond as necessary and import the design contours into the pond function to get the exact design. Otherwise you have to guess...

Use the pond wizard after you have the rainfall curve setup. It makes things pretty easy.

I would never go above 8%....25% is going to look terrible. Can you lower the foundation?

I do agree that sometimes we are better off to require a cash donation to improve or develop regional detention basins instead of having numerous small basins with unmaintainable restrictor sizes.

So your Tc for your pond would be about what the final Tc for the storm sewer system is?

I have always been a bit confused as to how to develop a proposed Time of Concetration in which to model detention. Most of the work my firm does are small (~5 acres commercial sites). Most time of concetration models assume all water is channeled directly to the pond. For instance, TR-55...

THANKS, THAT MAKES SENCE

Thank you for your help

So, if I am required to find the maximum discharge from a 5 acre site using the Huff rainfall distribution, should I run numerous different time intervals in the 1-4 quatiles to find my maximum discharge? If I run the 1 hour-1st Quartile, the discharge seems high to me. I am just trying to...

It does, but when I run the 3rd. qrt.-24 hrs, the peak runoff is significantly less that the scs 24 hour. I guess I am just confused about how to use the Huff curves.