IMPROVING FLOW MEASUREMENT AND EFFICIENT DELIVERY TO YOUR FIELD ZACK LIBBIN, MSCE, PE DISTRICT ENGINEER ELEPHANT BUTTE IRRIGATION DISTRICT

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1 IMPROVING FLOW MEASUREMENT AND EFFICIENT DELIVERY TO YOUR FIELD ZACK LIBBIN, MSCE, PE DISTRICT ENGINEER ELEPHANT BUTTE IRRIGATION DISTRICT

2 OBJECTIVES / TAKE AWAYS PURPOSE AND BENEFITS OF METERING HOW DELIVERY CAN BE IMPROVED FOR INCREASED IRRIGATION EFFICIENCY OPEN DITCH FLOW IMPROVEMENTS OPEN DITCH METERING METHODS

3 PURPOSE OF METERING CANT MANAGE IT IF YOU CAN MEASURE IT QUANTIFY IMPROVEMENTS IDENTIFY PROBLEMS VERIFICATION IMPROVING EFFICIENCIES

4 WELL METERING REQUIRED IN LRG EVALUATE PERFORMANCE PART OF DETERMINING EFFICIENCIES MONITORING EFFICIENCIES IDENTIFY PROBLEMS

5 WHAT IMPROVED IRRIGATION EFFICIENCY LOOKS LIKE LESS WATER REQUIRED FOR THE SAME BENEFIT = WATER CONSERVATION REDUCED DEEP PERCOLATION BELOW OR AWAY FROM ROOT ZONE REDUCED COSTS Where ec ea e(%) = 100 e = overall irrigation efficiency ec= conveyance efficiency ea= field application efficiency Root zone /Usable water Deep percolation Deficit Irrigation Efficiency = total water required water delivered to root zone for ET needs

6 IMPROVING IRRIGATION EFFICIENCY IRRIGATION TECHNIQUES BORDER-BASIN SURFACE IRRIGATION SYSTEMS CAN BE EFFICIENT LESS SEEPAGE PRIOR TO/DURING DELIVERY LEVEL FIELD/CORRECT SLOPE FOR YOUR SOIL TYPE FASTER IRRIGATION/REDUCED ADVANCE TIME UNIFORM APPLICATION REDUCED SURFACE EVAPORATION ELIMINATE RUNOFF SMALLER BLOCKS ET BASED SCHEDULING

7 IMPROVING CONVEYANCE EFFICIENCY TO YOUR FIELD A CLEAN UNIFORM DITCH LINED OR PIPED DITCH ADEQUATE FLOW CORRECTLY SIZED CANAL TURNOUT ADEQUATE PUMP(S) HIGH FLOW FIELD TURNOUT ADEQUATE DITCH CAPACITY EVALUATE RESTRICTIONS PRESSURIZE?

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9 BENEFITS TO IMPROVING A DITCH REDUCE SEEPAGE PRIOR TO DELIVERY REDUCED EVAPORATION LESS MAINTENANCE? IMPROVED FLOW IMPROVED HEAD LESS DITCH BREAKS

10 METERING YOUR DITCH WEIRS FLUMES DIRECT VELOCITY MEASUREMENT CIRCULAR GATE FACTORS TO CONSIDER DESIGN FLOW/CAPACITY RANGE OF FLOW COST ACCEPTABLE HEADLOSS SUBMERGENCE MAINTENANCE CONSTRUCTION AND INSTALLATION

11 METERING YOUR DITCH - WEIRS BROAD CRESTED SHARP CRESTED V-NOTCH Where Q = 2 3 c d 2g L H 3 2 Q = c d L H 3 2 Q = c d tan 2 H5 2 Q = flow Cd= discharge coefficient L = length of weir H = measured upstream head = V notch weir angle MEASUREMENT IS MADE BY OBSERVING OR RECORDING AN UPSTREAM HEAD/DEPTH PROS CONS EASY TO DESIGN EASY TO CONSTRUCT EASY TO READ LOW COST REQUIRES A RELATIVELY HIGH HEADLOSS NOT SELF CLEANING OR SELF DRAINING ACCURACY CAN BE EFFECTED BY APPROACH VELOCITY Photo credits: openchannelflow.com

12 METERING YOUR DITCH -FLUMES LONG THROATED RAMP WIN-FLUME SHORT THROATED Where CUTTHROAT SAMANI PARSHALL Q = c d h n Q = flow Cd= discharge coefficient H = measured upstream head n = flume design exponent PROS CONS EASY TO DESIGN EASY TO READ SOME ARE SELF CLEANING RELATIVELY LOW HEADLOSS CAN BE PORTABLE HIGHER COST SIGNIFICANT MATERIALS TO CONSTRUCT MODERATELY DIFFICULT TO CONSTRUCT AND INSTALL

13 METERING YOUR DITCH SAMANI FLUMES THREE SIMPLE FLUMES FOR FLOW MEASUREMENT: SAMANI, Z., (2017). THREE SIMPLE FLUMES FOR FLOW MEASUREMENT IN OPEN CHANNELS. J. IRRIG. DRAIN. ENG., /(ASCE)IR #STHASH.CPGVVTI0.DPUF RECTANGULAR (1) (S-M FLUME) (1) (2) (3) TRAPEZOIDAL (2) CIRCULAR (3)

14 REFERENCES AND ACKNOWLEDGEMENTS SAMANI, Z., (2017). THREE SIMPLE FLUMES FOR FLOW MEASUREMENT IN OPEN CHANNELS. J. IRRIG. DRAIN. ENG., /(ASCE)IR #STHASH.CPGVVTI0.DPUF BUREAU OF RECLAMATION, WATER MEASUREMENT MANUAL. 3RD ED., REVISED REPRINT, U.S. GOVERNMENT PRINTING OFFICE, WASHINGTON DC, SAMANI, Z., AND MAGALLANEZ, H. (1993). MEASURING WATER IN TRAPEZOIDAL CANALS. J. IRRIG. DRAIN. ENG., /(ASCE) (1993)119:1(181), SAMANI, Z., AND MAGALLANEZ, H. (2000). SIMPLE FLUME FOR FLOW MEASUREMENT IN OPEN CHANNEL. J. IRRIG. DRAIN. ENG., /(ASCE) (2000)126:2(127), SEE MORE AT: CLEMMENS, A.J.; WAHL T.L.; BOS, M.G., AND REPLOGLE, J.A PHOTOS: WATER MEASUREMENT WITH FLUMES AND WEIRS. ILRI PUBLICATION 58. PATRICK LOPEZ, EBID HENRY MAGALLANEZ ZOHRAB SAMANI OPEN CHANNEL FLOW.COM BLOG: RETRIEVED 2017