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<br />conduit submergence. The spillway rating and conduit rating as well as <br />the res,ervoir elevation capacity table are shown as well as the tail- <br />water for the conduit and spillway and the total diSCharge. The flood <br />routing is shown next, which in this case is based on an emergency gate <br />regulation operation using five feet of induced surcharge. When this <br />operation forces the gates fully open a storage indication routing is <br />made. The last column of this sheet shows the criteria (see Table 2) <br />used in mAkillg the release. <br /> <br />c. Run No.2. - This run shows the operation of' the spillway for <br />both the antecedent and the spillway design floods. It makes a spill- <br />way and conduit rating and then performs a flood routing. Releases <br />f'rom the reservoir are made according to the gate regulation curve until <br />this release becomes less than the previous period's release. When this <br />occurs the maximum gate opening obtained is maintained until the pool <br />elevation drops below the top of flood control pool. The releases dur- <br />ing this period are based on the discharge from the partially open gates. <br />When the pool drops below the top of flood control pool releases are <br />made which are equal to the average of the previous release and the <br />current inflow; but in no case to be less than the operational channel <br />capacity (CHCAP). When the pool starts rising again releases are again <br />based on gate regulation curves until the gates are fully open. At <br />this time a storage indication type routing is made. When the pool <br />drops below "BLTSUR" the routing type again changes. <br /> <br />d. Test Run No.4. - This test shows a valley spillway plan where <br />the spillway and conduit tailwater are both in the valley. The tail- <br />water shown for the two should be the same but as you can see there is <br />a slight difference because the conduit discharge was not used in com- <br />puting the spillway tailwater (note that the tailwater has practically <br />no effect on the spillway diSCharge). Both the spillway and conduit <br />discharges were used in computing the conduit tailwater (conduit tail- <br />water is the correct figure). This apparent error could easily be <br />corrected in the program but it would slow down the operation and would <br />not improve the accuracy IlIUch. Note that the tailwater rating curve's <br />maximum discharge of 318,000 c.f.s. prevented the rating curve from <br />going any higher. The flood routing is about the same as Run No.1 <br />except only three feet of induced surcharge was used. <br /> <br />e. Run No.5. - This run unlike the others is based on a trape- <br />zoidal spillway using a critical depth rating. The spillway does not <br />cause submergence on the conduit as shown by use of variable "ISPCTW". <br />The tailwater rating in this case is fictitious and causes no submer- <br />gence on the conduit and is not used for the spillway. This tailwater <br />curve was used because a good tailwater rating was not available and <br />would not affect the overall answer. Note the high approach loss of <br />2.0 f'rom spillway weir crest to the main reservoir. This loss was based <br />on backwater studies and was reduced in the computer program for lower <br /> <br />; <br /> <br />16 <br />