Embedded CMP culvert with Slope... Stream vs. Water Slide
Embedded CMP culvert with Slope... Stream vs. Water Slide
(OP)
i'm looking at adding culverts to a seasonal stream to make some road improvements. The state is requiring the culverts have a minimum of 18" of stone inside the bottom of the culvert so there is a natural stream bed. we would like to accomplish this with 36" or perhaps 42" Corrugated Metal Pipe, but i'm having trouble finding information about slope limitations for doing this. There is a pipe slope where we're just creating a water slide for rocks and i would like to understand those limits better. I'm not getting much out of the manufacturer reps i've reached out to, nor anything from the state either. anybody dealt with this and found info... or studied existing ones? fyi my slopes are 5%, 10%, 15% and 30%.





RE: Embedded CMP culvert with Slope... Stream vs. Water Slide
RE: Embedded CMP culvert with Slope... Stream vs. Water Slide
you need to look at your velocity. maybe a multiplate arch, preferably without invert would be better
RE: Embedded CMP culvert with Slope... Stream vs. Water Slide
RE: Embedded CMP culvert with Slope... Stream vs. Water Slide
RE: Embedded CMP culvert with Slope... Stream vs. Water Slide
The culvert with the biggest flow should only see 30 CFS during a 25-yr storm. i'm sure the actual behaivior is some combination of these variables: corrugation geometry, gradation of stone, slope of pipe, angle of repose for the stone, velocity of water, effective weight of submerged stone... but i really would love a reference to hang the hat on. Maybe i should bring this up next time somebody comes here without a thesis....
i'm trying to convince the State into letting the 30% go without stone lining. i hope they will see that this is a rare scenario which is outside the norm by which their rules and guidelines were developed, and they shouldn't worry about setting a precedent by this.
RE: Embedded CMP culvert with Slope... Stream vs. Water Slide
RE: Embedded CMP culvert with Slope... Stream vs. Water Slide
RE: Embedded CMP culvert with Slope... Stream vs. Water Slide
RE: Embedded CMP culvert with Slope... Stream vs. Water Slide
RE: Embedded CMP culvert with Slope... Stream vs. Water Slide
RE: Embedded CMP culvert with Slope... Stream vs. Water Slide
We've done cast-in-place concrete culverts on slopes up to 33% but keyed the culvert in every so often. I can't say any of the manufacturers I'm aware of have slope limitations other than trying to find a way to key it in. I believe we sized using our normal hydraulic procedures but then had to add an energy dissipator at the outlet. It's been a while since we did those...