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But can it increase a flow capacity problem downstream? Increase the peak flow as the new stormwater has more capacity than the existing combined sewer.

Does sewer network separation increase peak flow rate? e.g. Installing a new stormwater sewer next to an existing sanitary (combined) sewer. More precisely, if and only if the existing combined sewer is not able to carry a certain peak flow, installing a stormwater sewer that has the capacity...

We're looking for a submersible mixer to install in a water tower (submersible, powered, recirculation equipment for potable water reservoir). The overall volume of the tank is 1 000 000 US GAL and the maximum water level is 120 ft from ground. The area of the tank is 1200 square feet. Thing...

@cvg : I am reviewing for the owner.

Thanks beej67. This was done with PC-SWMM so the math seems to be alright. I just don't think this is "optimal" as the water level in the pond is "too high" for no reason (increasing the overall volume).

What if the pipe between the pond and the manhole is undersized? (this would act as an orifice as you mention).

I am reviewing a detention pond (Sketch attached). The designer determined 2 WSE : 1 for the detention pond maximum water level and 1 for the manhole with control structure maximum water level. Thing is, there's almost 1' between the 2 water levels. I'm guessing intuitively that there is...

Thanks for the answers. The reason behind this concept is mainly to reduce the amount of dead end on 2 separate pressure network (see concept attached - sorry for Paint :)). 3' might be too much here. We're dealing with rock and we wanted to use the existing trench as much as possible. I...

We have a project where we have to place 2 pipes parallel on a water distribution network. The pipe will be made of PVC DR-18 with diameters of 8'' and 6''. What would be the different considerations as to determine the distance between these two pipes? I was thinking of specifying at least...

What if all the points are 0,0 !? Seriously if you use a duration-intensity series then don't plot the 0,0 in Excel as it won't match the rest and you won't be able to use the (power) trendline. Just input the known values and with the equation y = Ax^-B calculate the y with a x of 5.

I'd then try to find out how were the IDF curves derived (measured data). If you can get to the data (e.g. 5 min maximum annual daily precipitation or else), you could (re)perform the statistical analysis with it and make that IF curve for 5 min. Less precise, but quick : Plot the x (minutes)...

Depends of what you're looking for to model. I'd rather use a culvert model (e.g. HydroCulv, HY-8) and input the peak flow (or else depending on what you're looking for) in it.

I recently had to debate with a technician about insulation of culvert. From my perspective, we try to put styrofoam above (horizontal) or as an inverted U around the pipe when we know that we're near the depth of penetration of frost. The technician says that they only put styrofoam under...

We have an old sewer force main (6 inches CPV). There is an high point/manhole with a check valve placed upstream the air release valve. It doesn't seem to be working. I would like to know what is advantage of placing a check valve before the air release valve? Should we replace both or just...

What’s the purpose of developing the term of specific energy for open channel flow? The concept of specific energy was introduced by Bakhmeteff in 1912. I like this explanation: For short reaches of channel, changes in specific energy related to the downstream decline in bed elevation or...

Some regulators here ask for wastesewer pipe to be SDR35 PVC while drainage has to be SDR28 PVC. I saw both to be SDR28 and some other ask for SDR28 for wastesewer and 35 for drainage. I'm not sure to see where this all comes from. Any clues?

So probably that the elevation of the "outlet 1" is below the minimum value of the elevation-storage (area) : you have to change that e.g. saying that this minimu elevation has 0 storage.

The storage-dischare or elevation-storage (or area) has to cover the same elevation in HMS. If you use the outlets option, it has to cover the elevation of the elevation-storage (or area)

The operator is missing something.

Any year storm in LA is nothing. The worst LA got over a year was about 30 inches.