As used in this article, “public project” means:
(a) A project for the erection, improvement, and repair of public buildings and works.
(b) Work in or about streams, bays, waterfronts, embankments, or other work for protection against overflow, except maintenance, repair, or reconstruction work.
(c) Supplies and materials used in maintenance, repair, or reconstruction work in or about streams, bays, waterfronts, embankments; or other maintenance, repair, or reconstruction work for protection against overflow.
The provisions of this article shall not change existing law regarding inclusion or exclusion of labor or materials used for completion of the project.
Except for the erection, improvement and repair of public buildings, the construction of dams, reservoirs, powerplants and electrical transmission lines of 230,000 volts and higher, nothing in this article shall apply to a publicly owned water, power or waste disposal system.