Culvert pipe size,

[simon-0116]

Local horsey paddocks have culvert thought field,
2 x 300mm pipes side by side.
With all rain they are running full hole and backing up because of debrie sticks etc. Normal / last 15 yrs been find.
Right so can alter it bit which senerio takes more water
1 x 900mm
Or
2 x 450mm.
These are sizes he's told me so may be not exact size.
Any ideas ??

 

[pycoed]

900mm will take 4 times as much water as a single 450mm & 9 times that of a 300mm

 

[Steevo]

900mm also won’t block as easily with twigs or a dustbin lid.

 

[C.J]

900mm will take 4 times as much water as a single 450mm & 9 times that of a 300mm

Correct and a 450mm will in theory take 2.25 as much as the 300mm.

 

[dannewhouse]

A 900 will also cost X times more!
You need a big grate and to clean it or spend a fortune on big pipes

 

[Steevo]

A bigger pipe could well flow faster too - less friction from pipe walls per litre.

 

[Agriimark]

Bigger the better but i would go 900, dont put a grate in front as this just causes it to block quicker, most stuff flows through, biggest problem with ditches is lack of maintenance, put a decent head wall in to, poured concrete, brickwork or ballast and cement filled hessian sacks stacked around the pipe.

 

[Matt L]

If you have 2 300 pipes then replace with one 600. More flow through and not even half the price of the 900.

 

[Mur Huwcun]

If the 2x 300 are near enough coping then wouldn’t another 300 be the cheapest way? How wide or long a culvert?

 

[Matt L]

The problem with multiple pipes is it’s not a clear span. As soon as bits of debris build up you can massively restrict flow. One loafer diameter pipe is always better than twins.

 

[Lincsman]

A 600 would be best option flow and cost wise, it is acceptable for it to back up for a few hours in peak times.

 

[averageguy54]

1X900 would be the way to go. Will flow a higher volume of water and less chance for blockage. Not to mention, that with global warming the potential for more erratic weather patterns including flash flooding from rain events, the 1x900 would be better at handling that type of water.

 

[Wombat]

Always go bigger than you think and go single pipe if you can. Twin pipe always seem to block on the join then floods when it backs up

 

[Lincsman]

A 600

A 600 would be best option flow and cost wise, it is acceptable for it to back up for a few hours in peak times.

PS 2 x 450mm are going to need a very wide ditch base.

 

[Wombat]

A 600

PS 2 x 450mm are going to need a very wide ditch base.

Agree on the single pipe, whether you can take a bit of back up is the question. Here we end up with it coming over upstream and flooding so never want any hold up so always go bigger. Just got a quote for 1.5m diameter pipe at the mo for one beck

 

[homefarm]

Could you slope the entrance and exit to the crossing and lower the covering over the pipes then it would flow over the top of the pipes when it rained heavily or blocks.
Depends on what is crossing I suppose. Last ditch we did we used 12 inch concrete pipes in the bottom just covered them with clay from the sides and sloped the entrance and exit at about 30 degrees. Very quick job with a digger. Works well for crossing with tractors and bale trailers up to now and no worries should it block.

 

[Smith31]

Where is the best place to purchase concrete pipe 900+ please? Travis Perkins are quoting nearly £500 for a single 2.5 metre length.

 

[Steevo]

Where is the best place to purchase concrete pipe 900+ please? Travis Perkins are quoting nearly £500 for a single 2.5 metre length.

You want seconds, not new.

Depends where you are - haulage can kill it.

Beavers are pretty good usually.

 

[Matt L]

Where is the best place to purchase concrete pipe 900+ please? Travis Perkins are quoting nearly £500 for a single 2.5 metre length.

Why do you want concrete? Plastic is a much better alternative as it is less brittle, easier to deal with, comes in 6m lengths

 

[Smith31]

Why do you want concrete? Plastic is a much better alternative as it is less brittle, easier to deal with, comes in 6m lengths

Will get a quote, see what the price difference is thanks