Pub. 15 2022 Issue 1 • UCLS Foresights 31 Visualizing the last great Grand Canyon expedition - ASU News This story originally ran in Backsights, Published by the Surveyors Historical Society Spring 2021, Volume 40 Number 1. See the accompanying article – Editor’s Pen: The Lost Canoe. “They ran a level line survey in oar boats for 260-some miles and closed within four feet (of the starting survey from downriver). There’s some very cool history there, including a flood from the Little Colorado River that came down on them as they were working their boats around Lava Falls. These maps, including the Glen Canyon, Cataract Canyon, Green, upper Colorado, and San Juan surveys were all completed in the early 1920s and ended the era of exploration. They were used extensively by later river runners. The oldest river guide I have found is from 1950. It uses these maps.” The intent was to explore possibilities for power generation, identifying potential dam sites. Claude Birdseye, the chief topographic engineer of the USGS, led the expedition. These weren’t zip-from-camp to-camp trips. The men had to maintain a line of sight from one survey point to the next, so they had to land – and hold their positions – every few hundred yards, even in rapids or where the canyon walls were almost vertical. They floated for two months and 19 days, from Lees Ferry to Needles, California. In all they selected 29 potential dam sites. The visualization shows the historical surveys in relation to things like modem river mile markers. “We’ve actually overlaid themwith historic aerial photography before the Glen Canyon Dam created Lake Powell,” he said. The Birdseye maps were ultimately used in the creation of two dams and a number of water diversion projects. Researchers today continue to use themaps, photographs and survey points – almost 100 years after they were collected. “They’re really significant,” said Bob Davis, chief of cartographic data services for the National Geospatial Program of the United States Geological Survey. “They provided quite a foundation to what became the topographic map division.” The original maps are in the library collection, bound in volumes. They’re accessible to anyone who would like to see them, but putting the collection online opens it up to anyone in the world with an internet connection. v Expedition 1923
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