Building lot elevation surveying

Old 11-29-07, 01:04 PM
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Building lot elevation surveying

Don't know where else to put this question-

I have a steeply sloped lot. I want to make an elevation plot so I can see where to put retaining walls, locate the slab, and make the grading cuts.

Any one ever done this with a laser level or a transit?

The lot is 150' x 225' and drops about 30-40 ft from front to back. I don't see how to 'check level' across 225 feet. Doesn't need to be really accurate.
Old 11-29-07, 03:46 PM
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A laser level will work fine. The method is to establish a base point at the high point (if you do not need to tie your survey to the exterior of the lot). Drive a stake deep enough so that it won't move and is almost flush with the ground. That is the base point (elevation 0). Set the level (or transit-level) up downslope but high enough that you can place your rod (ruler) on the base point and read it. Write that readng down. The actual height of any of your readings taken from that particular placement of the level is the reading minus what you wrote down. For instance, you read 1'1" from your base, then turn the level and take readings down the slope: 1'6", 3'5", 6'7". Your actual elevations are: 5", 2'4", 5'6" below base point.

You will have to set up intermediate points down the slope within range of each prior point to establish the height of your instrument when you move it.

Is that clear as mud now?

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