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<br />\. <br /> <br />, <br />'. <br /> <br />( <br /> <br />MANUALS-CORPS OF ENGINEERS <br />U.S; ARMY <br /> <br />EM 1110-2-1{08 <br />1 March 19GO <br /> <br />ENGINEERING AND DESIGN <br /> <br />ROUTING OF FLOODS THROUGH RIVER CHANNELS <br /> <br />CHAPTER 1 <br /> <br />INTRODUCTION <br /> <br />1-01. PURPOSE AND SCOPE. This manual describes and illustrates several practico.l methods of <br />applying scientific principles to the rOllting of f1C)od discharges in natural rivers or artificial channels. <br />Two basic types of approximate flood-routing methods are demonstrated. This manual is issued for <br />the guidance of individuals in all Divisions and Districts having responsibilities in Civil Works activities. <br /> <br />1-02. REFERENCES. Appendix II contains a selected bibliography of literature pertaining to f1ood- <br />routing techniques. ReJere",,';s'in t.he text to items in the bibliography are indicated by numbers in an <br />e"ponential position. <br /> <br />1-03. RESCISSION. This manual supersedes Engineering Manual for Civil Works Construction, <br />part CXIV, chapter 8, Hydrologic and Hydraulic Analyses, Routing of Floods Through River Channels <br />(preliminary), dated September 1953. <br /> <br />1-04. BACKGROUND INFORMATION. The term "flood-routing", as used in tnis manual, identifies <br />the proeedure by which a flood discharge hydrograph at any point on the stream is determined from a <br />known discharge hydrogrnph at some point upstream. Presently known procedures for theoretical <br />ano.lysis of the movement of flood waves in open channels are complex. A discussion of the general <br />theoretical and mathematical bas,es of the flood-routing methods demonstrated herein is beyond the <br />scope of this manual. The reader is referred to the publications listed in the selected bibliography of <br />appendix II for a discussion of such theoretical aspects. <br />^ great many different methods and procedures for solving flood-routing problems have been <br />described in engineering literature. In general, those methods that. attempt a strict mathematical <br />treatment of the many complex factors affecting flood-wave movement are not adaptable to the practical <br />solution of problems of routing floods through long re"ches of natural river channels. In order to keep <br />the amount of comput"tio]1s within practieallimits and 'to conform to limits ordinarily imposed by the <br />type and amount of hasic data available, it is generally necessary to use approximate flood-routing <br />methods that either ignore some of the factors affecting f1ood-wa ve movement at are based upon simpli- <br />fying assumptions in regard to such factors. The two basic types of such approximate methods discussed <br />in this manual are: (1) "storage routing" methods, in which energy factors are largely neglected and <br />only the effects of storage in the intervening reach and local inflows are considered in estimating changes <br />in the flood waVe as it passcs through a reach of channel, and (2) methods of approximating flood-wa\'e <br />shape at the lower end of a reach by time displo.cement of values of avero.ge inflow into the reach: Of <br />the storagr-routing methods, the coefficient (or Muskingum) method is given prin('ipo.l attention in this <br />manual with other method. explained or compated in terms of fo.ctors determining th~se routing coeffi- <br />cient.s. <br /> <br />1-05. NOMENCLATURE. A list and definition of symbols used in formulas in this manual are pre- <br />sented in appendix 1. Symbols shown in the quoted material have been modified as necessary to conform <br />to this list. <br /> <br />1 <br />