Highlight 8-19 of the HRS Guidance Manual, page 226
- Draw flow lines perpendicular to the nearest upgradient contour line from the edges of each source.
- Extend the flow lines between contour lines in the upgradient direction until a topographic high is encountered (a closed ring on a topographic map).
- A roadway and railroad tracks are located on opposite sides of the surface water body.
- The roadway and railroad tracks are upgradient of the sites and are considered to divert runoff from the sites.
- Boundaries of the drainage area do not extend beyond the railroad tracks or roadway.