Daniel Bowman wrote:Hi, this question might be a simple yes/no kind of deal-- in my experience (older Garmin 60Csx backpacking GPS) the accuracy of a waypoint or track is usually +/-30ft from the actual location you are at. If you want a more accurate waypoint, you have to stand there for several minutes while the GPS runs the numbers and averages out a better reading.. to about +/-5ft. Given all the inaccuracy and waiting involved, I would prefer to flag out my contours with a laser transit or even a homemade a-frame or bunyip. Is my Garmin just blown out of the water by newer GPS technology? Thanks.
Jerry McIntire wrote:R Scott, I'm looking forward to your reply about GPS models and costs. That kind of accuracy would be useful as we will be doing keyline design this summer on a small property.
Daniel Bowman wrote:More info or advice on where to find engineer-grade tools for rent in my area would be greatly appreciated. I am working about 4 acres of sloped pasture, 2 acres of flat-ish bottomland and 18 acres of steep woodland.. kind of borderline overkill for the high-tech route and dodgy for running heavy equipment on these slopes. I prefer a small diesel BCS 2-wheel tractor for terrace and swale building. I wonder if there is a quicker solution for flagging contours to rip keylines (one at a time!) with a walk-behind tractor, though.
Daniel Bowman wrote:Love that idea, Grant! We have Oak-Hickory woods (with a lot of Tuliptree) up to the top of our ridge and are beginning to replant and diversify the understory (currently overgrown with multiflora rose). Thinning on contour is a great way to begin building trail switchbacks. The log berm can be further staked out and stabilized with mushroom logs. I am planning on ripping into the pasture this spring and running some alley tree crops. The slope is too much for a full-sized tractor, so it will be slow-going.. but worth it.
Patrick Freeburger wrote:I wanted to do swales on a 1% grade. I assume the same idea of a 5' pvc pipe with a handheld sight level would work, but use a 7' pvc pipe with black and red tape at 6'. Step out 100' and line up the level on the 6' high mark and I should have your 1% drop. I am curious on pros/cons of on-contour vs. moving water with a 1% or 2% drop? Also for steep slopes does 2% make more sense than 1%, both making switchbacks easier and moving water a little more quickly to prevent washouts? I have a 32 degree slope (200' rise over a 330' run) with very little top soil under my sage and coyote brush. I don't think I can get a subsoiler to get in pulled by a BCS or otherwise, but the idea of dropping small tree along the path may work. Any other ideas on my 20 acres would be appreciated.