The construction of Brantley Dam and Reservoir represents a substantial betterment of the Carlsbad Project's physical plant, increasing both water storage and dam safety. The price paid for these improvements, however, was the loss of part of the historic fabric which had resulted in the Carlsbad Irrigation Project being designated a National Historic Landmark in 1964.  These losses include the draining of McMillan Reservoir and the proposed future use of the reservoir basin by Brantley Reservoir, as well as the breaching and partial inundation of McMillan Dam itself.
In accordance with Section 106 of the National Historic Preservation Act of 1966, as amended, the Bureau of Reclamation and the Advisory Council on Historic Preservation determined in 1977 that Brantley's construction would have an adverse effect on the National Historic Landmark as defined in 36 CFR 800. To mitigate, in part, this adverse effect, the Bureau of Reclamation agreed to sponsor a historic survey and recordation of the Carlsbad Project according to the standards of the Historic American Engineering Record (HAER). This historical narrative is one principal product of the HAER survey; other products include measured drawings, photographs, and a revised National Historic Landmark Nomination. This material is being deposited as part of the permanent HAER collection at the Library of Congress. 
1. Early determinations of the district's historic significance may be found in Department of the Interior, National Park Service, National Survey of Historic Sites and Buildings inventory form for the Carlsbad Reclamation Project, September 1963; Department of the Interior, National Park Service, National Register of Historic Places Inventory Nomination Form for the Carlsbad Reclamation Project, December 8, 1975.
Last Updated: 01-Feb-2008