We have been doing some survey work -- trying to determine the best spot for a homesite, well, septic tank and pole barn. It is tough going as parts of the forest are very thick with shrubs and vines. But so far we think we have a site picked out.
One tool that I "built" is our water level. It works pretty well for what it is. It can determine the elevation difference of two spots up to 40 feet apart -- and you can go around trees. It is actually very accurate.
Two lengths of wood with measuring tapes starting at the top taped on ( I could have just used a marker to mark the lines but ...) to the poles. Then 50 feet of clear plastic tubing filled with iced tea ... to make it easy to see the height.
When the two poles are level the water is at the same mark on each pole. If there is a difference in level it is the difference between the two tape measure readings. So if the water line on one is at 20 inches and the other shows 5 inches there is a difference of 15 inches between the two spots.. This is important to know if you want to build swales.
Next trip out there we will start looking for countour lines.