Below is a simple sketch showing the application of a water level.
There is actually only one hose. A 5 gallon plastic bucket works well. I like 5/8" to 3/4" hose but I guess any size would work.
I first mark a reference mark about 1' from the end of the hose. This assures that I have the same volume of water in the bucket each time. I can then move to a location, move the hose up or down until the water is at the mark, and then measure the height of the water in the hose to the object. I can then move to any other location and repeat the process.
Another option is to attach a rigid ruler/scale on the end with the hose attached along the length. I can then just place the end of the scale on the object and read the height on the scale. This eliminates the need for verifying the water is at the same fill level in the hose.
The same can be done without the bucket but often takes two people.
The advantages of this over the lasers, transits, and auto levels are
The disadvantages are
Since 10 November 04