Object :
Object of installation of “Electromechanical Digital Discharge Recorder” (DG-Meter) is to measure, record, store and print any relative change in water head and discharge of canal for 24 hours. Data transmission system will generate and display the following informative data on display board.
- Any relative change in water head of upstream side of H.R. gate with respect to canal bed level. This may be upstream of H. R. gate OR reservoir level.
- Any relative change in water head of downstream side of H.R. gate with respect to canal bed level.
- Any relative change in H.R. gate No.1, 2, 3 etc.,for gate opening in meter.
- Value of Cd with respect to opening of gate as per area curve.
- Relative discharge in downstream side of canal after H.R. gates.
- Date, time of recorded data.
Basic Pirnciple Used for Discharge Measurement :
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For discharge measurement in canal, “Driving Head” principle is used. Head regulators are used to control discharge in the main canal. Discharge formula is as below.
Q = Cd X A X √2GH Where Q - Discharge in canal in Cu. Meter/ Second.
Cd - Coefficient of discharge and value is depending on percentage of
gate opening.
A - Average cross sectional area of gate openings when no of gates are
installed in series.
g - Acceleration due to gravity = 9.8 M/sec².
H - Driving head = (H1 – H2).
H1 - Available head in canal at upstream side of H.R.gates from sill level.
H2 - Available head in canal at downstream side of H.R. gates from sill level.