Holding pond calculations

[Doing it for the kids]

Trying to take on the local planners with out spending vast sums on engineers.

Planning for another New shed going in soon, will probably need a holding pond to help with flooding. Last time we guessed how big the pond would be and got it wrong by about 600m3!

Is there a rough calc that can be used to work out how many m3 you need for a m2 of New hard standing?

Working on the last project’s outcome, I think it’s about 10m2/m3 which is a big volume to area ratio

This is on the assumption that soak away/ natural percolation is not possible no other option but pond and hydro brake at 2 l/s I think.

Has anyone tried to do this themselves?

 

[Exfarmer]

10. sq.m. will give a volume of 1000 litres or 1 cu.M . in the event of 100mm of rain , which I think is judged to be a 1 in 100 year event.
If I was doing one, I would make it a permanent pond feature which could fill by a further metre in the event of good flood with an outlet allowing your 2l/s
this would discharge a cumec in 8mins 20 secs
They do not like soakawys as groundwater can be polluted, ponds can also trap sediment etc
so a 464 square meter building plus the same again out front would require a pond about 10metres by 10metres or double with a .5 metre surcharge
wild life would love it

 

[Doing it for the kids]

all agreed.

on clay though no soakaway option, but a pond wont be wet in the summer. Its in a good location and I wanted to save the land for more commercial, not ponds really. I am also governed by the outflow which is not very deep. I worked out about 10 x 10 @1m deep as well, see if / what they ask for.

just got planning for a bigger grainstore 100m away and they haven't asked for anything on there though!?

 

[Exfarmer]

Sounds like you have a very exciting project!