While researching my 4th year studio for winter quarter 2012, I discovered that the source of some of my favorite drawings of the Los Angeles Aqueduct is now a Google Books: http://books.google.com/books?id=7yIWAAAAYAAJ
Commissioners, Los Angeles (Calif.). Board of Public Service. 1916. Complete report on construction of the Los Angeles aqueduct; with introductory historical sketch; illustrated with maps, drawings and photographs. Los Angeles Department of Public Service.
InfraSCAPE Design Lab 
how could i see the “Complet
e report on construction of the Los Angeles Aqueduct (1916)” ……?
Google Books has a scanned version that is easily found. Not many public libraries have copies, but several universities do (but tend to keep it in the reserved stack or rare book collection). Amazon often has reproductions for sale, and original editions occasionally are for available (ebay/alibris/amazon) for $250-$450