Boise River Cross Sections

Conducted in cooperation with Federal Emergency Management Agency

Elevation Reference Marker Data

Elevation Reference Marker location map (HTML 3kB)
Elevation Reference Marker location list (XLS 18kB)
Site Descriptions (markers 88-154) (PDF 538kB)
Site Descriptions (markers 155-340) (PDF 388kB)
Site Descriptions (markers 341-Y415ECC) (PDF 359kB)

The vertical control for this project was established as part of a sub-contract for contour mapping of the area. Primary control points were set by the contractor for use in the development of 2-foot contour maps. The points were based horizontally on the North American Datum of 1983 (NAD 83) and vertically on the North American Vertical Datum of 1988 (NAVD 88). The general location and identification number of each control point are shown on the map.

Boise River, USGS Idaho Water Science Center employee locating cross sections using GPS.

The primary control points were established using differential, dual frequency, global positioning system (GPS) units. The minimum setup session at each point lasted approximately 15 minutes, while most sessions were 20 minutes or longer. Satellite data was logged by the receiver at 10-second intervals. The GPS network consisted of several loops with a maximum of 10 points per loop. Each loop was closed separately using GPS software. The final vertical adjustment was based on holding 10 local surveyed bench marks constant. GEOID96 was used as the geoid model for the adjustment. The accuracy for these points was determined to be approximately ± 2 cm vertical and ± 1 cm horizontal.