Contour lines design problem

Hi,

i've got a 7 ha land. It has some slopes and downhills with <3% inclination. I've read a lot and seen lots of videos of people marking their contour lines easily with A-frames so i decided to do the same.

But then i get to the land and it's not that easy. Why? because the soil in itself is not level, it has rocks and holes and clumps of dirt so i cannot even mark two level points.

Am i making myself understand?

How do i resolve this problem?

Andre

If you're dealing with little lumps and holes, either flatten it or fill it in so it's relatively even with the surrounding soil. I've dealt with this myself and found that one side of a lump will be too high and the lower side is too low. I just whack the lump a few times with the back of a spade and find the level point from there. Usually i'm talking about a difference of less than a centimeter. Once you dig out the swale it really won't matter. You can just dig a little deeper or shallow depending on how the water moves in the swale.

Perhaps your A-frame is too small a tool for a property this size and you might not need so fine a detail in your contours. Try using a hose level or some other tool that can "bite" off a larger segment at a time. If you need to you could go back along the roughed in lines thus laid out with the A-frame at the areas where you really need the fine detail.
Another observation hint that is huge: put on your rain gear and go walk the property in a good hard rain, one heavy enough to cause runoff. You will then see how water moves over the landscape and in what volume, where it gathers, where erosion is a danger, etc. Almost nobody thinks of this, and yet I've found it as useful, or moreso, than any amount of mapping.....

Thank you for answers guys.
I've found out what the problem was, instead of making a semi-circular movement i just had to lift the A-frame and move it. Somehow, when i made that semi circular rotation the a-frame would be unleveled, don't know why it happens but it does.

Alder, i thought about the situation in which the A-frame would give me too much detail for a 7 ha land so i'm not very demanding in the level position.
About the observation hint, thanks for that and i will do it, unfortunately it won't rain here in the next few weeks (months? ) so i have to make the preparations now while observing it dry. At least in my land it's fairly obvious where the rain goes and how's the erosion situation at.

Cheers

Andre Lemos wrote:Thank you for answers guys.
I've found out what the problem was, instead of making a semi-circular movement i just had to lift the A-frame and move it. Somehow, when i made that semi circular rotation the a-frame would be unleveled, don't know why it happens but it does.

Your level might not be calibrated properly. If you label the legs "A" and "B", you want to work across the land such that you pivot on alternating legs. If you're looking up hill and working to the right you'd start with the level in "AB"position and mark your ground position to start. Everything from that point will be level with that spot. Pivot on the B side of your level and then make the next level mark on the A side (which would now be on your right hand side). Then continue by pivoting on the A side. Keep alternating like this til you get to the end of your line. By doing this with a correctly calibrated level you'll eliminate any minor errors. If the level is not calibrated right and you just keep A side on the left and B side on the right without alternating, you'll stack your errors and end up way off contour by the time you get to the end of the line.

Just to double check myself on my A frame level, I made sure the cross piece was level as well and I mounted a small carpenter's level to it. If the bubble and the string agree I know I have it all right.


This may help.


Good luck