concrete base fall

[dogglercowman1]

Making a small silage pit for extra products.
It is roughly 80 ft by 25 ft.....the area is already dug out and is 16 inches higher at the back running to where I'm starting.....width ways will be level..can someone tell me the what the height needs to be at the back to draw effluent correctly to the front bearing in mind it already has a 16 inch fall..

 

[Tarw Coch]

I’ve never heard of a correct fall for a silage pit, does it really matter all that much?
Minimum amount of fall to let surface water run forward would suffice I should think, 16” over 80’ sounds a lot of fall to me but can’t see why it wouldn’t be ok, depends if you want to avoid the extra work of digging down at the back to lessen the fall.

 

[averageguy54]

I would use a minimum 2% grade. That's what road builders use as a number to keep water off roadways. If my calculations are right, that would be 19".

 

[Mur Huwcun]

An inch per 15foot bay would make more sense, I’ve looked at our 90foot one long enough and If I remember correctly from looking at the side perlins and top of L oanels that the back is about 6 inches higher!!! 60foot cattle shed here built in 70s is half a block higher at the back and that’s a good slope. I split a tractor there once and only once!!!