1

Leveling Computations

Chapter 5

Adjustments of Level Circuits

Level Circuits can be adjusted based on the lengths of lines leveled or the number of setups between benchmarks.

2

Adjustments of Level Circuits

100.24A

-7.310.5

3.0

107.55D

-8.470.8

116.02C

+5.420.7

110.60B

+10.601.0

100.00A

ΔElevationElevationDistance (mi)BM

Misclosure = + 0.24’

Adjustments of Level Circuits

A

0.5/3.0(-0.24) = -0.040-7.310.5

-0.243.0

D

0.8/3.0(-0.24) = -0.064-8.470.8

C

0.7/3.0(-0.24) = -0.056+5.420.7

B

1.0/3.0(-0.24) = -0.080+10.601.0

A

AdjustmentΔElevationDistance (mi)BM

Misclosure = + 0.24’

3

Adjustments of Level Circuits

100.00A

-7.31 – 0.04 = -7.35-0.04

0.00-0.24

107.35D

-8.47 – 0.06 = -8.53-0.06

115.88C

5.42 - 0.06 = 5.36-0.06

110.52B

10.60 - 0.08 = 10.52-0.08

100.00A

Adjusted Elevation

Adjusted ΔElevation

AdjustmentBM

Adjustments of Level CircuitsAdjusted Level Circuit:

4

Reciprocal Leveling

Used when leveling across rivers, lakes and canyons.

Reciprocal Leveling

Multiple Rod Readings are determined across river, lake or canyon.

5

Reciprocal Leveling Example

3.956.52

3.976.51

3.965.486.538.06

F.S. to AB.S. to BF.S. to BB.S. to A

At Point YAt Point X

Reciprocal Leveling across a wide river gives the following rod readings in feet:

The elevation of point X is 5,000.00’. Compute the misclosure and elevation of point Y.

Reciprocal Leveling Example

Average = 3.96Average = 6.52

3.956.52

3.976.51

3.965.486.538.06

F.S. to AB.S. to BF.S. to BB.S. to A

At Point YAt Point X

At Point X: 8.06 – 6.52 = 1.54’ At Point Y: 5.48 – 3.96 = 1.52’

Misclosure = 1.54 – 1.52 = 0.02’ Average difference =

Elevation of Y = 5,000.00 – 1.53 = 4,998.47’

1.54 1.522+