A. HYDROLOGIC PROTECTION LEVELS

  1. Capital Flood Protection (based on runoff resulting from a rainfall with a probability of occurrence of once in 50 years). The following shall be designed for the Capital Flood:
  2. All regional facilities as described in the City of Palmdale Drainage Master Plan or as modified by the City Engineer.
  3. Natural Watercourses
  4. Open channels, closed conduits, bridges, dams, detention basins and debris basins which are constructed in or intercept flow from natural watercourses.
  5. Floodways.
  6. Natural depressions or sumps. Secondary overflow will be provided for all sump areas.
  7. Culverts under arterial highways, except interim low flow culverts constructed for the purpose of eliminating cross gutters.
  8. The lowest finish floor elevation of all habitable structures shall be a minimum of one-foot above the maximum water level resulting from a Capital Flood.

2. 25-Year and 10-Year Storm

All master plan and local drainage facilities will generally be designed so that:

  • The peak runoff from a 25-year storm will be contained within the street right-of-way (see Figure V-1).
  • The peak runoff from a 10-year storm will be contained at or below the street curbs (see Figure V-2).

V-2