Borewell Yield Measurement Borewell Yield Measurement Measurement A common way to describe the yield of a new borewell is in ‘ inches’ measured by the free, unrestrained flow of water from a borewell over a 90 degree ‘V’ notch. The basic principle is that the discharge is directly related to the height of the water level from the bottom bottom of the the V notch. notch.
h - Height of water level from the bottom of the V Based on certain equations and formulae, the height ‘h’ in inches is converted to discharge rate in litres per hour. The following table indicates the conversion of the yield in ‘inches’ to a discharge rate in litres per hour. V-Notch Reading in Inches
Approximate Discharge Rate in l.p.h.
1/4
95.4
3/4
261
1
597
1 1/4
1,045.00
1 1/2
1,650.00
1 3/4
2,425.00
2
3,382.00
2 1/4
4,558.80
2 1/2
5,919.00
2 3/4
7,501.00
3
9,329.00
3 1/4
11,402.60
3 1/2
13,720.00
3 3/4
16,284.60
Class
Low Yield
Average Yield
High Yield
Very High Yield
4
19,148.00
4 1/4
22,285.60
4 1/2
28,695.20
4 3/4
29,459.20
5
33,350.00
5 1/4
37,914.00
5 1/2
42,551.00
5 3/4
47,461.00
6
52,644.00
6 1/4
58,372.00
6 1/2
64,373.00
6 3/4
70,919.00
7
77,464.00
7 1/4
84,557.00
7 1/2
92,195.00
7 3/4
1,00,105.00
8
1,08,288.00
Superlative Yield
Source: http://www.lmnoeng.com/Weirs/vweir.php http://www.thehindu.com/features/homes-and-gardens/water-literacyhelps/article4931751.ece http://www.water-diviner.com/vnotch%20test.htm
