The degree of protection for which levees shall be designed shall be as follows:
a. For watercourses and channels, levees shall provide the degree of protection as specified in subsection 31-25.6;
b. For those areas to be protected from waters of San Francisco Bay and San Pablo Bay from the southerly and westerly boundaries of Contra Costa County to the State highway bridge at Carquinez Strait, levees shall provide protection from tides and from waves created by wind action. Tops of curbs shall be not lower than elevation 7.5 U.S.G.S. datum;
c. For those areas to be protected from the waters of Carquinez Strait and Suisun Bay from the State highway bridge at Carquinez Strait to Simmons Point on Chipps Island, levees shall provide protection from tides, flood flows in the Sacramento and San Joaquin Rivers, and waves created by wind action. The basis for flood protection shall be the U.S. Army Corps of Engineers’ standard project flood, approximately equivalent to a recurrence interval of two hundred (200) years. Tops of curbs shall be not lower than elevation 8.5 U.S.G.S. datum;
d. For those areas within the delta area from Simmons Point on Chipps Island to the easterly boundaries of Contra Costa County, levees shall provide protection from tides, flood flows in the Sacramento and San Joaquin Rivers and all waterways tributary thereto, and waves created by wind action. The basis for flood protection shall be the U.S. Army Corps of Engineers’ standard project flood, approximately equivalent to a recurrence interval of two hundred (200) years. Tops of curbs shall be not lower than elevation 9.5 U.S.G.S. datum.