The following drainage regulations apply to land both within and outside of the Coastal Zone. The reference to ordinance numbers beginning with 22 refer to provisions of the Land Use Ordinance, Title 22 of the County Code, and numbers beginning with 23 refer to the provisions of the Coastal Zone Land Use Ordinance, Title 23 of the County Code. Any difference between the two provisions, if any, will be specifically noted.
22.05.040 or 23.05.040 - DRAINAGE:Standards for the control of drainage and drainage facilities provide for designing projects to minimize harmful effects of storm water runoff and resulting inundation and erosion on proposed projects, and to protect neighboring and downstream properties from drainage problems resulting from new development. The standards of Sections 22.05.042 or 23.05.042 through 22.05.050 or 23.05.050 are applicable to projects and activities required to have land use permit approval.
22.05.044 or 23.05.044 - DRAINAGE PLAN PREPARATION AND CONTENT:Drainage plans are to be neatly and accurately drawn, at an appropriate scale that will enable ready identification and recognition of submitted information. The County Engineer may require drainage plans to be prepared by a registered civil engineer.
A. BASIC DRAINAGE PLAN CONTENTS: All drainage plans shall include the following information about the site.
(1) Flow lines of surface waters onto and off the site.
(2) Existing and finished contours at two-foot intervals or other topographic information approved by the County Engineer.
(3) Building pad, finished floor and street elevations, existing and proposed.
(4) Existing and proposed drainage channels including drainage swales, ditches and berms.
(5) Location and design of any proposed facilities for storage or for conveyance of runoff into indicated drainage channels, including sumps, basins, channels, culverts, ponds, storm drains and drop inlets.
(6) Estimates of existing and increased runoff resulting from the proposed improvements.
(7) Proposed erosion and sedimentation control measures.
(8) Proposed flood-proofing measures where determined to be necessary by the County Engineer.
B. ENGINEERED PLAN CONTENT: Engineered drainage plans are to include an evaluation of the effects of projected runoff on adjacent properties and existing drainage facilities and systems in addition to the information required by subsection a. of this section.
22.05.050 or 23.05.050 - DRAINAGE STANDARDS:
A. DESIGN AND CONSTRUCTION: Drainage systems and facilities subject to drainage plan review and approval that are to be located in existing or future public rights-of-way are to be designed and constructed as set forth in the county Engineering Department Standard Improvement Specifications and Drawings. Other systems and facilities subject to drainage plan review and approval are to be designed in accordance with good engineering practices.
B NATURAL CHANNELS AND RUNOFF: Proposed projects are to include design provisions to retain off-site natural drainage patterns and, when required, limit peak runoff to predevelopment levels.
C. AREAS SUBJECT TO FLOODING: Buildings or structures are not permitted in an area determined by the County Engineer to be subject to flood hazard by reason of inundation, overflow, high velocity or erosion, except where such buildings or structures are in conformity with the standards in Section 22.07.066 or 23.07.066 and provisions are made to eliminate identified hazards to the satisfaction of the County Engineer. Such provisions may include providing adequate drainage facilities, protective walls, suitable fill, raising the floor level of the building or by other means. The placement of the building and other structures (including walls and fences) on the building site shall be such that water or mudflow will not be a hazard to the building or adjacent property. The County Engineer in the application of this standard shall enforce as a minimum the current federal flood plain management regulation as defined in the National Flood Insurance Program authorized by United States Code Sections 4001-4128 and contained in Title 44 of the Code of Federal Regulations, Part 59 et seq., which are hereby adopted and incorporated into this title by reference as though they were fully set forth herein.
The CZLUO adds an additional subsection as follows:
D. DEVELOPMENT ADJACENT TO COASTAL BLUFFS: The drainage plan shall incorporate measures to minimize increased erosion to the coastal bluff as a result of development.