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<br />e <br /> <br />. <br />" <br /> <br />/' <br /> <br />e <br /> <br />. <br />~ <br /> <br />. <br />. <br /> <br />e <br /> <br />. <br /> <br />100000 <br /> <br />, <br /> <br />1.011..2 t 2, S"O. ~. <br /> <br />lI.LlI'lO'1f "tV,," <br /> <br />EM 1110-2.1416 <br />15 Oct 93 <br /> <br />. <br />" <br /> <br /> <br /> ... <br /> H' <br />. <br />. <br />, I <br /> ... <br /> I <br /> I <br /> I <br /> ... J <br /> '" <br /> <br /> <br />'" <br /> <br />" <br />I <br /> <br />.. <br />tlDV_a <br /> <br />~Yfta8TOK MYNAS 0.' ..rAGB <br /> <br />----- :0;.....2 ""0 'UIOA08D a ora.oJ: <br /> <br />:0;..012 KO VRGAGED 0 7I.OW <br /> <br />" <br />I <br /> <br />11 11 <br /> <br />')I'CIll <br /> <br />.. <br />I <br /> <br />11 21 <br /> <br />.. <br />I <br /> <br />.>a..l. <br /> <br />Figure 5-6. Simulation of the illinois River et Kingston Mine. without 2,579 squere <br />mile. of ungaged drainage <br /> <br />may be a determining factor in the accuracy of the <br />model. For the DJinois River, unsatisfactory results were <br />produced if inflows from greater than 100 square miles <br />were not entered at a point. <br /> <br />5-7. Steps to Follow In Modeling a River System <br /> <br />The following is a sequence of steps 10 follow when <br />modeling a river system using unsteady flow. In subse- <br />quent sections, some of these topics will be expanded. <br /> <br />a. Prepare schematic diagram. The basic schematic <br />diagram shows the layout of the river system and the <br />principal tributaries for which gaged flow data are avail- <br />able. It is best to model every tributary for which <br />cross-sectional data are available since the degree of <br /> <br />detail determines the accuracy and consistency of the <br />simulation. Also, tribotaries can be modeled at modest <br />additional cost in computer time and engineer effort. <br />The scope of the model should be large enough so that <br />errors in the downstream boundary condition do not <br />affect results at the locations of interest. An example <br />schematic diagram for the Red River of the North is <br />shown in Figure 5-9 (U.S. Anny Corps of Engineers <br />199Oc). <br /> <br />b. Collect cross-sectional data. Collect all the <br />cross-sectional data available on the main stem and tribu- <br />taries. If data are old, or suspect for any reason, new <br />data may be required. Usually cross section data are <br />unavailable on all but the largest tributaries, thus limiting <br /> <br />5-9 <br />