Contra Costa County |
Ordinance Code |
Title 9. SUBDIVISIONS |
Division 914. DRAINAGE |
Chapter 914-2. MINIMUM REQUIREMENTS |
§ 914-2.010. Drainage facilities — Minimum capacities.
(a)
Storm drainage facilities directly affecting the subdivision shall have the following minimum capacities:
(1)
Major drainage facilities (i.e., those serving a watershed area four square miles or greater) shall have adequate capacity to contain with sufficient freeboard a fifty-year frequency of average recurrence interval runoff and contain without freeboard a one-hundred-year average recurrence interval runoff;
(2)
Secondary drainage facilities (i.e., those serving a watershed area one square mile or greater but less than four square miles) shall have adequate capacity to contain with sufficient freeboard a twenty-five-year frequency of average recurrence interval runoff;
(3)
Minor drainage facilities (i.e., those serving a watershed area less than one square mile) shall have adequate capacity to contain with sufficient freeboard a ten-year frequency of average recurrence interval runoff.
(b)
As used in this division, the terms "storm drainage facility" and "drainage facility" shall include, without limitation, channels, ditches, conduits (e.g., pipes and culverts), detention basins and all appurtenances.
(Ords. 89-28, 78-5).