ROAD SURVEYING Section I. RECONNAISSANCE SURVEY PREPARATION AND SCOPE

The reconnaissance survey is an extensive study of an entire area that might be used for a road or airfield. Its purpose is to eliminate those routes or sites which are impractical or unfeasible and to identify the more promising routes or sites. Existing maps and aerial photographs may be of great help. Contour maps show the terrain features and the relief of an area. Aerial photographs show up-to-date plani-metric details. The reconnaissance survey must include all possible routes and sites. The reconnaissance survey report should summarize all the collected information, including a description of each route or site, a conclusion on the economy of its use, and, where possible, appropriate maps and aerial photographs. Design Design and military characteristics should be considered during the reconnaissance survey. Keep in mind that future operations may require an expanded road net. A study of the route plans and specifications is necessary. If these are unavailable, use the following as guides. Locate portions of the new road along or over existing roads, railroads, or trails, whenever possible. • • • • • • • Locate the road on high-bearing-strength soil that is stable and easily drained, avoiding swamps, marshes, and organic soil. Locate the road along ridges and streamlines, keeping drainage structures to a minimum. Keep the grade well above the high waterline when following a stream. Select a route as near to sources of material as practical, and locate the road along contour lines to avoid unnecessary earth work. Locate the road on the sunny side of hills and canyons, and on that side of the canyon wall where the inclination of the strata tends to support the road rather than cause the road to slide into the canyon. Locate roads in forward combat zones so that they are concealed and protected from enemy fire. This may at times conflict with engineering considerations. Select locations which conserve engineer assets, avoiding rockwork and excessive clearing. Avoid sharp curves and locations which involve bridging.