Fresno County, California

In 1923, the United States Geological Survey (USGS) organized an expedition to map the remaining stretch of the Colorado River along the Grand Canyon to from Lee’s Ferry to Diamond Creek (Arizona). The expedition resulted in the successful mapping of the Colorado River through the Grand Canyon, provided a sound understanding of the geology and hydrology of the region, and eventually led to the construction of the Hoover Dam in 1963. The boats Marble and Boulder are of considerable historical significance as they are two of the four original survey boats used to survey the perilous Grand Canyon expedition of the Colorado River conducted by the USGS in1923.

At the request of the Nevada Bureau of Reclamation, Lower Colorado Dams Office, aconservation assessment was conducted on two historic boats. Marble and Boulderare currently located at Southern California Edison Company (SCE), Big Creek Powerhouse in Fresno County, California. The objective was to assess the condition of the boats and provide the information requested by the Bureau to assist them with their decision to acquire the two vessels for interpretive display at the Hoover Dam Visitor Center, Nevada.

The assessment included: examination of historic documentation pertaining to the construction and use of the boats; an on-site examination of the boats at SCE; a review of the current storage conditions; and an evaluation of proposed display locations based on information provided by the client. Recommendations for the conservation treatment of the boats, including transportation to Nevada, possible display options, and storage/display requirements, as well as a budgetary cost estimate for the work were provided. At the request of the client, an appraisal of the boats was also made by a qualified boat appraiser.

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