I am currently looking a parcel of land for a projected permaculture farm. The intention is to raise a moderate amount of livestock (primarily goats and sheep) in conjunction with a food forest. This land is about 35 acres. Without getting into all the details regarding soil types, slope, etc, I have one main concern, which is water: the land has a deep well which pumps at 35 gal/min. This is all the water that will be available on this land, other than rain water, which is considerable in certain seasons (PNW). I havent been able to find any clear info on the amount of water needed to run the kind of operation I am envisioning, so my question to you all is how far will this water go and how much will it prove a limitation. Thanks much.
If you plan for water conservation, and water catchment, you can go a long ways towards making that well work fine. 35 gallons a minute means you can almost fill an average bathtub to the top.in a minute (if you go to the overflow, it would fill your tub in a minute). It will provide 2100 gallons an hour.
Swales, catch ponds, mulch, hugels, will all help towards enough water. Have a good look at the topography and slopes of your site and plan to manage the water as a resource. It will greatly help. There are many articles here on Permies about all of those systems.
As Deb has given some great methods already rain catchment is only difficult when using large tank sizes and that is more about placement and routing that water.
The more you can conserve your well water, the better. In many areas of the US ground water levels are dropping from overuse and that water doesn't come back quickly.
Chris has given you really good numbers on per animal volume numbers.
35 gallons a minute is a lot. My folks bought a 20 acre farm in the Willamette Valley that originally came with a 5 gpm well, they had a new well dug that produced 30 gpm, more than any other well within a couple miles.
Unless you're planning on irrigating the whole 35 acres in some sort of thirsty crop, you should be fine. The devil, of course, is in the details, but the right selection of plants for your area will do well most years without any supplemental irrigation. A lot of crops respond well to dry land farming, even some that are surprising, tomatoes for example.
The amount needed for the livestock is negligible.
My opinions are barely worth the paper they are written on here, but hopefully they can spark some new ideas, or at least a different train of thought
We get about 12 inches of rain a year, I have about 1000 square Metres of roofing over sheds and the house and can store about 300,00 litres
of fresh water at anyone time.
I have two dams set in the ground which catch water via channels in the adjacent forest, which is unusual, and can store about 1 million lures in those.
So instead of using the well, consider tanks.
Now things may be different where you are, tanks are very common in Australia and just about every building will have gutters to catch any rain run off. I am aware some areas
of the world do not collect rain off roves, do you?
John Daley Bendigo, Australia
The Enemy of progress is the hope of a perfect plan