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<br />e <br /> <br />e <br /> <br />e <br /> <br />2-5 <br /> <br />The following steps are needed: <br /> <br />1. <br /> <br />Draw a preliminary centerline in pencil on the mosaic, showing <br />curves, intersecting angles, etc. Plot and measure intersection <br />angles by the tangent method for accuracy. To locate the center <br />of curvature accurately, erect perpendiculars - do not use triangles. <br /> <br />2. <br /> <br />Walk the full length of the flood plain, noting on an ozalid print <br />of the aerial mosaic: <br /> <br />Probable channel realignment, <br />Points of significant breaks in gradEl, <br />Location of all channel cross sections obtained with a hand <br />level, <br />Location of all rock outcrops or critical soil conditions, <br />Approximate locations where valley cross sections mayor <br />should be obtained, <br />Location of significant tributary junctions and places where <br />side inlets may be needed, <br />Location of all homes, institutions, roads, parks and recreation <br />areas that maybe effected by the channel work. These <br />include but are not limited to facilities that are within <br />500 feet of the alignment, <br />Location of tree areas and large individual trees adjacent <br />to the alignment, <br />Location of utili ty crossings, such as: powerlines, telephone <br />lines (aerial or buried) and pipelines. Obtain hand-level <br />cross section of the channel at all visible pipeline crossings <br />to show general relation of the pipeline elevation with <br />the present channel bottom and bank elevations, and <br />Location of fence lines and/or apparent property lines, foot <br />bridges, etc., if not already visible on aerial photo. <br /> <br />3. <br /> <br />Make a photo record of the landscape surrounding the project and <br />record the viewsheds of the project from view points. <br /> <br />4. <br /> <br />Following the field check, accurately establish the revised centerline <br />on the photo mosaic. The final selection of alignment should be <br />based on full use of all cross section, geologic and environmental <br />data. <br /> <br />5. <br /> <br />Show the actuallocation of all surveyed cross sections on the photo <br />mosaic. <br /> <br />If suitable aerial photographs are not available it will be necessary <br />to establish a base line in the field by means of an instrument survey. <br />Where feasible, the base line should be located close to the improvement <br />area but outside of brushy or wooded areas and any probable construction <br />