【正文】 ss Section Data: Geometry and reach lengths 橫截面數(shù)據(jù)：地形和河岸長度_ Loss Coefficients: Manning roughness expansion and contraction loss coefficients損失系數(shù)：人員，膨脹和收縮損失系數(shù)Starting Water Surface Conditions 起始水面的條件_ Boundary Condition Specification (choose one) 邊界規(guī)定（選其一）_ Known water surface elevation 已知水面高度_ Compute critical depth 計算臨界的深度_ Compute normal depth given EGL slope 在EGL斜坡基礎(chǔ)上計算正常的深度_ Interpolate WSEL from provided rating curve 在水位流量關(guān)系曲線上插入WSEL_ Flow Regime (choose one) 水域（選其一）_ Subcritical 近乎危急的? Requires downstream boundary conditions 需要下游的邊界條件_ Supercritical 超臨界的? Requires upstream boundary conditions 需要上游的邊界條件_ Mixed flow regime (subcritical amp。HECGeoRAS模塊運行操作過程:在ArcView導(dǎo)入HECGeoRAS模塊后,會出現(xiàn)PreRAS、GeoRAS_Util、PostRAS三個菜單。②非恒定流模擬?？蓪蝹€河段、樹枝狀河系或河網(wǎng)的緩流、,逐斷面采用直接步進法推求水面線。對于該流態(tài)HECRAS從下游河段開始計算,并沿著相鄰的橫斷面逐段向上游計算直至結(jié)束,而急流則剛好相反。 Pr=1為臨界流。無量綱數(shù)佛汝德數(shù)(Fr)用以判斷流態(tài),即: Fr1為緩流。如果在某個橫斷面處的流量以及水面線的高程已知,則直接步進法就能對其鄰近的橫斷面的水面高程進行求解。計算過程是從上游或從下游開始,要依據(jù)流態(tài)的類型。Fr1為急流。對于自然界或者人工明渠或天然河道而言,緩流是一非常普遍的流態(tài)。（１）恒定流水面線計算。恒定流的模擬可應(yīng)用于洪泛區(qū)管理和洪水保險研究,其特點是:多項目分析、多曲線計算、多橋涵分析以及實現(xiàn)分流最優(yōu)化。其計算原理基于連續(xù)性方程和動量方程。GeoRAS主要功能模式及運行過程:在ArcView的PreRAS菜單中導(dǎo)入所研究區(qū)域的TIN (Triangular Irregular Network—三角形不規(guī)則格網(wǎng))文件,繪出地形等高線,然后在其上建立河道中心線、中泓線、岸線、橫斷面切割線等,結(jié)合GeoRAS_Util菜單里面的,從地形使用的shapefile文件里創(chuàng)建曼寧系數(shù)值n的分布表格,生成RAS輸出文件,在HECRAS中導(dǎo)入前一步生成的RAS輸出文件,進行河道水力的模擬后生成第2個RAS輸出文件,接著在Arc View的PostRAS菜單下導(dǎo)入該第2個RAS輸出文件,進行洪泛平原區(qū)的勾勒以及河流速度,水深的圖面效果顯示。 supercritical) 混合的流動方式（近乎危急amp。如模式（HEC－RAS，HEC－2）在上游不起作用，水面剖面將傾向普通深度。25Multiple Profiles Can Be Defined 可以界定多層側(cè)面_ Computes up to 2000 profiles in single run一個單程最多估算2000個側(cè)面_ Flow rates and some other data may change 流動速度和一些其他可能變化的數(shù)據(jù)Expansion and Contraction Loss Coefficients 膨脹和收縮損失系數(shù)Contraction Loss Coefficients 收縮損失系數(shù)No Transition Loss Computed Gradual Transition 逐步轉(zhuǎn)換 Bridges (or Culverts with Wing walls) 橋梁（或隧道）Abrupt Transitions (and most Culverts) 陡然轉(zhuǎn)換（大多數(shù)排水渠）Expansion Loss Coefficients 膨脹損失系數(shù)No Transition Loss Computed Gradual Transition Bridges (or Culverts with Wingwalls) 橋梁（或隧道）Abrupt Transitions (and most Culverts) 陡然轉(zhuǎn)換（大多數(shù)管道）Required at starting cross section and at following flow change locations 在起始橫截面和下列流動變化位置被需要26Manning Roughness Coefficient Options 配置粗糙系數(shù)選項_ Three Roughness Subareas (monly used) 三個粗糙分區(qū) (普遍使用)_ Called NC Records in HEC2 terminology 在HEC2術(shù)語中被稱為NC記錄_ Define left overbank, right overbank, and channel roughness values 定義左邊的河灘 ，右邊的河灘和河道粗糙價值_ Multiple Roughness Subareas (sometimes used) 多重的粗糙分區(qū) ( 有時使用)_ Called NH Records in HEC2 terminology 在HEC2術(shù)語中被稱為NH記錄_ Horizontal roughness values vary by cross section horizontal stationing 根據(jù)水平橫截面，水平粗糙值不斷變化_ Allows more detailed roughness areas to be defined 允許定義更為詳細的粗糙區(qū)域_ Up to 20 roughness subareas 最多達到 20個粗糙分區(qū)_ Vertical Roughness (rarely used) 垂直的粗糙 ( 很少使用)_ Called NV Records in HEC2 terminology 在HEC2術(shù)語中被稱為NV記錄_ Vary by WSEL elevation or flowrate 根據(jù) WSEL 海拔或流量而改變_ Up to 20 entries can be defined 可以定義20個條目_ Similar to HEC2 NV records 類似 HEC2 NV 記錄28Vertical Roughness 垂直_ Roughness changes with elevation or discharge 粗糙程度隨高度或流出量改變Defining Cross Sections 定義橫截面_ Orientation 方位_ Left to right, looking downstream 從左到右，俯瞰下游_ Increasing in river station (cross section ID) as you move upstream 當移向上游時，增加河流位置（橫截面ID）_ Spacing 間隔_ Depends upon characteristics of stream and purpose of study 取決于河流特征和研究目的_ Location 位置_ To define reaches of similar characteristics 定義相似特征的流程_ Number of cross sections 橫截面數(shù)量_ Up to 400 cross sections allowed per river reach 每個河流流程最多允許400個橫截面30Cross Section Layout 橫截面布局_ Cut cross sections perpendicular to flow 垂直于水位截取橫截面_ Don’t allow cross sections to overlap each other when cutting 截取時橫截面不能互相重疊在一起Cross Section Data 橫截面數(shù)據(jù)_ Section ID Number 橫截面的ID數(shù)字_ HECRAS refers to it as River Station, HEC2 called it cross section number HECRAS把它看作河流位置，HEC2稱其為橫截面數(shù)字_ Arbitrary: Usually represents stream stationing 隨意性：通常表現(xiàn)出河流的位置_ Must increase as you move upstream 當移向上游時必須增加31Cross Section Data (more) 橫截面數(shù)據(jù)（更多）_ Channel Bank Stations 河岸位置_ Usually denoted with mud line 通常用泥漿線表示_ Designates when flow is in channel or out of bank 在河道或出河道流時進行指明_ Represents the distance (or chainage) that the flow travels from the current cross section to the next downstream cross section描繪距離（或測得的距離）即水流從當前的橫截面到下一個下游橫截面流淌的距離_ Place in the centroid of the flow area 放置在流域的重心_ Reach length may change with different flow values 流程長度可能隨不同的水量值改變32Cross Section Data 橫截面數(shù)據(jù)_ Measure flow length relative to the centroid of the flow area 測量與流域的重心有關(guān)的流動長度Cross Section 橫截面_ Elevation Values 海拔_ Can be negative 可能不符_ Station Values 位置值_ Cannot be negative for HEC2 符合HEC2 的程序_ HECRAS supports negative stationing HEC RAS 支持崎嶇位置_ Must increase in value 必須在數(shù)值上有所增加_ Up to 500 cross section coordinates per cross section 每一橫截面有多達500個橫截面坐標_ Called GR Records in HEC2 Terminology 在HEC2 術(shù)語中被稱為GR 為記錄33Ineffective Flow Areas 無效的流域Two Methods of Defining “Dead Storage” Areas 兩種定義 備用庫存 區(qū)域的方法_ Define “Normal” (HEC2 style) ineffective flow areas 定義“常規(guī)”（HEC2模式）無效的流域_ Define (up to 10) “Multiple Blocks” ineffective flow areas 定義（多達10個）“多重阻礙”無效的流域_ Once WSEL overtops, then area bees effective again (considers this flow area) 一旦WSEL重疊，地區(qū)開始再次變得有效（考慮這類流域）? Otherwise, mark as “Permanent” and ineffective area is never considered available for flow 否則，被認為是“永久”和無效的區(qū)域不再適合水流動Ineffective Area Options 無效區(qū)域的選擇_ Given stations with test elevations 通過試驗海拔確定位置_ Sediment deposition (elevation, HEC2 only) 沉淀物沉積（海拔，僅僅是HEC2）_ Commonly used at bridges to define ineffective flow areas 通常用于橋梁，定義無效流域Ineffective Flow Area 無效流域Right Ineffective Flow 右無效流動Right Ineffective Flow 右無效流動34Run Options: 運行選擇Friction Slope Method