Aquaculture Engineering

Unit 1- Surveying

Find out the elevation of points using different methods

Rise and Fall method

Problems

3. The following staff readings were observed successively with a level, the instrument having been moved after third, sixth and eighth readings.

2.228, 1.606, 0.988, 2.090, 2.864, 1.262, 0.602, 1.982, 1.044, 2.684 m.

Enter the above readings in a page of a level book and calculate the R.L. of points, if the first reading was taken with a staff held on a bench mark of 432.384 m.

Check = ∑BS-∑FS = ∑rise = ∑fall = first RL – last RL
=5.964=6.916=2.842=3.794=432.384-431.432
=0.952 0.952 0.952

4. The following consecutive readings were taken with a level and 5 m. levelling staff on continuously sloping ground at common intervals of 20 m.
0.385, 1.030, 1.925, 2.825, 3.730, 4.685, 0.625, 2.005, 3.110, 4.485

The reduced level of the first point was 208.125. Rule out a page of level field book and enter the above readings. Calculate the reduced levels of the points by rise and fall method.

Check = ∑B.S. = ∑F.S. = First R.L = Last R.L
1.01 = 9.17 = 208.125 = 199.965
= 8.16 = 8.16