Hey all! I've been a lurker on here for a long time but finally decided to register so I could ask this question:
Attached is a topo map of a portion of our property that we are converting from row crops to pasture. We'd like to keyline pattern cultivate before we start dividing into paddocks and planting trees etc.
Can anyone help me identify where exactly our keylines/keypoints would be?
The images still are not there for me.
Just remember, as Darren Dougherty has said, that the Keyline was originally phrased "the Keyline of the valley." Figure out your valley's keypoints, then you have to figure out how your various valley keylines/keypoints will mesh. And then, as Mark Shepard has said, don't stress too much about getting it exactly right.
Unfortunately there is only one line with elevation marked (750) so it is hard to give you a key point or even a place to start observation.
The way you determine keypoint(s) is to observe where water begins the downhill journey during a rain event or by the tops of gullies (which is where the water gathers to go downhill).
This upper most point is the keypoint and there would be a pond placed there, then swales with berms run at a 1% down hill grade from that point out to intersect the ridge line on either side.
If you happen to know the co-ordinates (gps) for the site, and you post those, I can take a look at the satellite images and give you better help with identifying the important start point(s).
If you are in an area with more than 3 junctions of water passage, then you want a main line setup instead of a key line setup, because that will work better for you.
"If you are in an area with more than 3 junctions of water passage, then you want a main line setup instead of a key line setup, because that will work better for you."
Bryant, I respect you greatly, but I'm a little confused by the above quote, and I thought I had a better handle on keyline than most. Can you elaborate on "main line setup" or refer me to a pertinent resource? Thanks, Peter
Keyline was developed in Australia where watersheds tend to be very simple, unlike say the Mississippi river watershed with literally hundreds of streams feeding it as it moves along.
The best book I've found for understanding the differences between Keyline and Mainline water control systems is Mark Shepard's book "Restoration Agriculture".
I tried using the keyline methods on my own land and created very bad situations down the hillside. I switched to the Mainline system Mark developed and the blow out situations are gone.
When you have steep land like I have, the key line creates huge water plumes that create springs down hill. In many areas that can be a blessing but it can also be a curse if you have to go that direction to get to town.
In our case, it caused complete road erosion and that is not a good thing. By moving the water and designing for overflow sheeting of water to the next swale system, we took care of the problem.
Thank you, that explains it. I reread the Earth Shaping and Water Management section, and while I see talk of swales, keyline patterns, etc., I don't quite see what you're talking about here. Think that must have come later as you said.
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