Water pressure at end of a outfall?

coatsandrew · Oct 17, 2016

I'm trying to determine the water pressure at the exiting end of a 66" storm water pipe. Max flow is 10 ft/s. Suggestions?

Thanks

SlideRuleEra · Oct 19, 2016

LittleInch - You are right about the high flow capacity of the 66" pipe. The impoundment I know of (a city park lake) covers 10 acres. A few times a year, there may be a 6 ft. tide rise/fall in say 6 hours. So, an average of 10 acre-feet per hour of water through a 66" pipe (I don't know the size of the exiting inlet/outlet). For those conditions I get a flow rate of 5.1 fps. Briefly, at peak tidal flow during the 6 hours may be 7 fps. During a hurricane storm surge, the water rise would be much faster... but probably not designed for that.

Depending on how much "sag" (mainly horizontal, but some vertical at low tide) there is in the cable holding the floating screen, the pull on the piling could be a good bit more than the two tonnes on a flat plate.

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