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I I I I I I I I I I I I I I I I I I I spreadsheet with Excel and sorted into individual cross sections. A Macro can be used to sort and save the cross-sections in separate lab delimited text files that can be opened as a new view in ArcView. A Macro is a series of commands and functions that are stored in a Microsoft Vi\;ual Basic module and can be run whenever a specific automated ta"k needs 10 be perfonned. The use of a Macro can significantly save time when the same operation will be repeatedly performed. For each cross-section the lowest elevation point is extracted and saved in one lab delimited text file to be used as the points for the river centerline in ArcView. The GPS tab delimited text files are added into the ArcView "Tables", which are then added to the view with "Add Event Theme:' Using the X-tool.. ArcView extension, created by Mike DeLaune of the Oregon Depanment of Foresty. the separate cross-sectional points are convened into polylines. which are then merged into one file containing multiple polylines. The centerline points are added to the '"Tables" in ArcView and added to the view with "Add Event Theme". The points are made into a poly-line that designates the centerline of the river reach. The view is then projected into an appropriate coordinate system with the appropriate map and distance units. The selection of the coordinate system and units should be made based on the geographic location of the study area. the coordinate system of other GIS data. and the desired units of the data. The merged theme of the cross sections is then convened to a shapefile. saving the shapefile in the projected units. A Triangular Irregular Network (TIN) is then created from the other GIS data using contours as mass points for the elevation and the merged cross-sectional polylines and the centerline polyline as hard brake lines. The TIN is created to assign elevations to each point. The HEC-geoRAS ArcView extension. created by the Army Corps of Engineers Hydrologic Engineering Center, is then used to create an expan file that can be impaned into HEC-RAS. The HEC-geoRAS extension also requires the 3D Analyst ArcView extension to function. A streamline, cut lines. flowlines. a 3D stream centerline, and 3D cross section lines are created from the preRAS menu created by the extension and a RAS GIS file is created that is ready for Hydraulic Analysis using HEC-RAS. For funher information on the HEC-GeoRAS ArcView extension refer to the HEC- GeoRas User's f\.tanual. 17