Handbook for Agrohydrology (NRI) 
Chapter 2: Measurement of runoff 

Appendix A1: Rating tables for H flumes, HS flumes and HL flumes
Rating Tables given in the USDA Agriculture Handbook 224 are in feet and inches. If metric measurements are required, conversions can be made using the following conversion factors. 1 inch 2.54 centimetres 1 foot 0.3048 metres 1 cubic foot 0.02832 cubic metres 28.32 litres
Because of the size of increments used in the rating tables (0.1 and 0.01 ft.), interpolation may be necessary when conversions to SI units are undertaken. Linear interpolation is permissible and does not lead to serious inaccuracies. Below are presented two conversions of rating tables to SI units, for a 30 cm deep H flume and for a 90 cm deep H flume. Together, these two sizes of flume and their rating table conversions will cover the range of discharge measurements encountered by most agrohydrological projects.
Rating Table 30 cm H Flume
(litres second^{1})
Rating Table 90 cm H Flume
(litres second^{1})
90 H Flume Rating Table continued
Rating Tables for Various Depths of H Flume (feet^{3} second^{2})
Flume 0.5 foot deep
Flume 0.75 foot deep
Flume 1.0 foot deep
Flume 1.5 feet deep
Flume 2.5 feet deep
Flume 2.5 feet deep  Continued
Flume 4.5 feet deep
Rating Tables for Various Depths of
HS Flumes (feet^{3} second^{1})
Rating Tables for HL Flume 4 Feet
Deep (feet^{3} second^{1})
Appendix A2: Construction details of multislot dividers
Figure
Figure
Appendix A3: Construction details rotary slot dividers
Figure
Figure
Alternate Design for N1
CoschoctonType Runoff Sampler
Figure
Appendix A4: Rating table for broad crested (triangular weirs)
For conversions into SI units:
1 foot = 0.3048 metre,
1 square foot = 0.09290 square metre
Rating Tables for Various Crosssectional Areas of Channel 10 Feet (3m) Upstream of Centre of Crest (feet^{3} second^{1})
2:1 Triangular weirs
3:1 Triangular weirs
3:1 Triangular weirs continued
5:1 Triangular weirs
Appendix A5: Capacities and dimensions of parshall flumes
For conversion to SI units
1 inch = 25.4 mm
1 foot = 0.3048 metre
1 cubic foot per second = 1 secondfoot = 0.02832 cubic metres per second = 28.32 litres per second
Figure