Profile surveys along Henrys Fork, Idaho, and Logan River and Blacksmith Fork, Utah

In order to determine the location of undeveloped water powers the United States Geological Survey has from time to time, alone and in cooperation with State organizations, made surveys and profiles of some of the rivers of the United States that are adapted to the development of power by low or medium heads of 20 to 100 feet.

The surveys are made by means of plane table and stadia. Elevations are based on heights derived from primary or precise levels of the United States Geological Survey. The maps/are made in the field, and show not only the outlines of the river banks, the islands, the positions of rapids/falls, shoals, and existing dams, and the crossings of all ferries and roads, but the contours of banks to an elevation high enough to indicate the possibility of using the stream. The elevations of the various bench marks left are noted on the field sheets in their proper positions. The figures given with the gaging stations shown on the maps indicate the elevation of the zero of the gage.