How to use a Dumpy Level Example 1

How to use a Dumpy Level Example 1 Find the difference in height between the benchmark and the top of the slope ? Top of Slope Divide hill into 3 spots to make easier Otherwise too far to see or leveling staff not long enough

How to use a Dumpy Level Example 1 9 m. AOD (above sea level) Back sight

How to use a Dumpy Level Example 1 Rotate Dumpy round 9 m. AOD (above sea level) Back sight 2 m. AOD (above sea level) 2 m Foresight Move Level to new position

How to use a Dumpy Level Example 1 Move Dumpy to new position 6 m. AOD 9 m. AOD Back sight 2 m. AOD Foresight Back sight

How to use a Dumpy Level Example. Rotate 1 Dumpy round to new position 6 m. AOD 9 m. AOD Back sight 2 m. AOD Foresight Move Level to new position Back sight

How to use a Dumpy Level Example 1 6 m. AOD 9 m. AOD Back sight 1 m. AOD 2 m. AOD Foresight Back sight Foresight

How to use a Dumpy Level Example 1 1 m. AOD 9 m. AOD Level of dumpy = 922 m Back sight 9 m 6 m. AOD 2 m. AOD Foresight Level of dumpy = 926 m Back sight 2 m 6 m Foresight 1 m 6 m + 920 m 913 m + 9 m Height of Backsight instrument Foresight Height of new Ground (from (Ground Level (from point (Height Level Dumpy + Backsight Dumpy of instrument Level) from Dumpy Level) -foresight) Level) Bench mark 913 9 922 2 920 6 926 1 925

How to use a Dumpy Level Example 1 ? Height of Backsight instrument Foresight Height of new Ground (from (Ground Level (from point (Height So the difference in height is Level Dumpy + Backsight Dumpy of instrument 925 m-913 m=12 m Level) from Dumpy Level) -foresight) Level) Bench mark 913 9 922 2 920 6 926 1 925

Example 2 I want to construct a water pipe on the hill? To find the pressure that will result from the pipe I need to know the height difference between point A and point D A= 875 m. AOD B C D

Example 2 Height of Foresight Height of new Backsight instrument Ground (from point (Height of (from Dumpy (Ground Level + Level Dumpy instrument. Level) Backsight from Level) foresight) Dumpy Level) Benchmark A=875 B= B= C= C= D= A= 875 m. AOD B C D

Example 2 Level of dumpy=879 m. AOD A= 875 m. AOD 4 m 9 m B Level of dumpy=871 m. AOD 1 m 11 m B= 870 m. AOD Level of dumpy=862 m. AOD 2 m C 12 m C= 860 m. AOD D D= 850 m. AOD

Example 2 Benchmark Ground Level Backsight (from Dumpy Level) Height of instrument (Ground Level + Backsight from Dumpy Level) A=875 4 879 9 B= 879 -9=870 B= 870 1 871 11 C= 871 -11=860 C= 860 2 862 12 D= 862 -12= 850 Foresight Height of new (from point (Height of Dumpy instrument. Level) foresight)

Example 2 Benchmark Ground Level Backsight (from Dumpy Level) Height of instrument (Ground Level + Backsight from Dumpy Level) A=875 4 879 9 B= 879 -9=870 B= 870 1 871 11 C= 871 -11=860 C= 860 2 862 12 D= 862 -12= 850 Once you have gone down the hill, check you answer by coming back up the hill Ground Level Backsight (from Dumpy Level) Height of instrument (Ground Level + Backsight from Dumpy Level) Foresight Height of new (from point (Height of Dumpy instrument. Level) foresight) D=850 C= C= B= B= A=

Example 2 Level of dumpy=879 m. AOD 4 m A= 875 m. AOD 9 m B Level of dumpy=871 m. AOD 1 m 11 m. Level of dumpy=862 m. AOD B= 870 m. AOD 2 m C 12 m C= 860 m. AOD D D= 850 m. AOD

Example 2 Benchmark Ground Level Backsight (from Dumpy Level) Height of instrument (Ground Level + Backsight from Dumpy Level) A=875 4 879 9 B= 879 -9=870 B= 870 1 871 11 C= 871 -11=860 C= 860 2 862 12 D= 862 -12= 850 Once you have gone down the hill, check you answer by coming back up the hill Foresight Height of new (from point (Height of Dumpy instrument. Level) foresight) Ground Level Backsight (from Dumpy Level) Height of instrument (Ground Level + Backsight from Dumpy Level) D=850 12 862 2 C=862 -2=860 C=860 11 871 1 B=871 -1=870 B=870 9 879 4 A=879 -4=875 Foresight Height of new (from point (Height of Dumpy instrument. Level) foresight)

Example 2 So what was the change in height? Change in height= 25 m A= 875 m. AOD B C D A= 850 m. AOD

Summary Questions 1. What is a Dumpy Level Used for? 2. What 2 things can you use to check if things are level? 3. How does a spirit level work? 4. One you have done a backsight reading what would you do next with a dumpy level?