Laserfiche WebLink
<br /> 1.0 (3) <br /> 0.5 (2) ~ REFERENCE LEVEL <br /> (I)~IO <br />- <br /> 15 20 25 30 35 40 <br />E 0.0 <br />z (-I) ~ HYDRAULIC HEAD 1 <br />0 -0.5 LEVEL i <br />i- (-2) /I. DELIVERY HOSE <br /><( (-3) <br />> -1.0 OUTLET LEVEL <br />w I <br />...J (-4) <br />w ./'LGROUND LEVEL <br /> -1.5 (-5) <br /> (-6) <br /> -2.0 (-7) (l00) (200) (300) (400) (600) <br /> 20 40 60 80 100 120 140 160 180 200 <br /> DISTANCE FROM WATER SOURCE. m (ft) <br /> <br /> <br />Figure 8,--Hydraulic head, delivery hose outlet, and ground levels 0 <br />as functions of distance from the water source. The lateral pipe ID <br />changes from 102 mm (4 in) to 76 mm (3 in) at 100 m (330 ft). <br /> <br />Of course) the lateral could be tapered more by using smaller dic..;n- <br />cter pipe at the end, but presently, the price reduction is negligible <br />for diameters less than 76 nun (3 in). USL1g smaller pipe ,wuld also <br />decrease the maximum flow velocity that could be attained within the <br />lateral for flushing. <br /> <br />i'hshing lateral lines periodically will often be necessary to re- <br />f.lOve accumulated sediment. In the example illustrated in Fig. 8, <br />:einoving the end plug ,wuld allow a 3 m (9.8 ft) head to be dissipated. <br />'[;,i.s ,wuld penuit 3.4 R-/sec (54 gpm) to Go" through the lateral. The <br />velocity "ould be 0.8 m/sec (2.6 ft/sec) through the 76-oun (3-in) ID <br />13teral section, but only 0.4 m/sec (1.4 ft/sec) through the 102 nlm (4 in) <br />.section. Hhether this velocity is sufficier.t to resuspend sediment Hill <br />G2)end on the particle size distribution within it. Making the lateral <br />2~tirely with 102-nun diameter pipe would per."it a flushing velocity of <br />0,7 m/sec (2.2 ft/sec). Experience with silt-laden irrigation "ater <br />i~o~ the Snake River near Twin Falls, Idaho, in an irrigation systeffi <br />(1{orstell, 1975) with flow velocities less than these, indicates flushing <br />t~e lateral lines weekly by removing the end cap prevents sediment <br />accumulation. 5 <br /> <br />5Personal conununication wi th <br />vation Research Center, Kimberly, <br /> <br />R. V. Worstell, Snake River Conser- <br />Idaho. <br /> <br />r', .""0";, <br />v \...' ~ V ," U <br /> <br />-10- <br />