Fish Hatchery Management - fisheries & aquaculture

FISH HATCHERY MANAGEMENTTABLED_I.RELATIONBETWEENHEADANDDISCHARGEFORCIPPOLETTIANDREC.TANGULARWEIRS.DISCHARGEVALUESASSUMEAI.FOO.I.-LONGWEIRCREST;FoRSHORTERORLONGERCRES'[S,MUL'I.IPLYTHESEVALUESBYTHEAC'l.UAt,I,ENGTH_il "i1_HEAD(INCHES)0.2500.5000.7501.001.251.50t.7 52.002.252.502.753.003.253.503.754.00DISCHARGE(CALLONSPER MINUTE)5r.0014.023.036.050.066.0ti4.0102l'221431651882t2237263290HEAD(INCHES)4.254.50+.7 55.005.255.506.006.',256.506.757.007.257.507.75u.00DISCHARGL'(CALLONSPER MINUTEJ3t734(t37s40543(;46u50053356760163667270u7457U3u20HEAD(INCHES)tt.258.508.759.009.259.509.7510.010.310.5l0.ttI 1.0I 1.3l 1.5II.ti12.0DISCHARC;E(GAI-LONSPI]R MINUTE]u(;090093997ul,020l,0fi01,100I ,1501,1901,230l,2tt0I,320I,3701,410I,4601,510(g) fne weir crest, formed with a metal Plate, must be leak-proof' sharpor square-edged, and no thicker than |-inch'The distance of the weircrest above the bottom of the channel should be at least 2| times the waterhead on the weir to minimize aPproach water velocities'(a) eir must have access to the underside of falling water as it flows overthe weir crest. otherwise, air pressure may force water against the downstreamface of the weir, increasing the rate of discharge above the flowrates indicated in Table D-l'(S) fne channel above the weir must be straight, level' and clean toensuresmoothwaterflow.Sedimentanddebrisshouldnotbeallowedtocollect on or behind the weir.