The Floodway Overlay Zone F is intended for application in those areas of the city within floodways or water courses in which flood control structures and facilities are either required or planned to be installed or improved. In order to protect the public health, safety and welfare, the construction of buildings and structures within such areas shall be prohibited until adequate flood protection facilities are constructed or guaranteed to be constructed and temporary alternate arrangements are made to protect persons and property.

Whenever the following words or terms are used in this chapter they shall have the meaning ascribed to them in this section:

A.

"100 YEAR FLOOD" means a flood level with a one percent or greater chance of being equaled or exceeded in any given year, which is determined from an analysis of historical flood and rainfall records and computed in accordance with the latest edition of the San Diego County Hydrology Manual and the latest Flood Insurance Rate Map (FIRM) issued by the Federal Emergency Management Agency (FEMA).

(Ord. 2002-2726 § 1; November 12, 2002)

B.

"FLOODWAY" means the channel of a watercourse and the adjacent land areas required to carry and discharge a flood.

C.

"SUBSTANTIAL IMPROVEMENT" means any repair, reconstruction, or improvement of a structure, the cost of which equals or exceeds 50% of the market value of the structure either (i) before the improvement is started or (ii) if the structure has been damaged and is being restored before the damage occurred. For the purposes of this definition, "substantial improvement" is considered to occur when the first alteration of any wall, ceiling, floor, or other structural part of a building commences whether or not that alteration affects the external dimensions of the structure. The term does not, however, include any alteration to comply with existing state or local health, sanitary, building, or safety codes or regulations.

D.

"WATER COURSE" means any waterway, gully, ravine, ditch, channel, canal, conduit, culvert, or drain in which waters flow in a definite direction or course either continuously or intermittently and includes any area adjacent thereto subject to inundation from a 100 year flood.

All uses and structures permitted in the underlying zone shall be subject to the same conditions and restrictions applicable to such zones and the following:

a.

The construction of new or substantial improvements of permitted residential structures shall not be permitted unless the lowest floor (including basement) is elevated to or above the level of the 100 year flood.

b.

The construction of new or substantial improvements of non-residential structures shall not be permitted unless the lowest floor (including basement) is elevated to or above the level of the 100 year flood or the structure, including attendant utility and sanitary facilities, is floodproofed to the level of the 100 year flood.

c.

The improvement of the building site, either initially or after a principal use has been established, shall not involve any of the following unless a permit to do so has been first obtained from the City Engineer: (i) impair, impede, or accelerate the flow of water in a water course (ii) alter the surface of land by construction, excavation, embankment or otherwise, so as to reduce the capacity of a water course (iii) construct, alter, or remove any flood control or storm water drainage structure facility or channel of or in a water course (iv) construct or place any structure in, upon, or across a water course or (v) place earth fill or encroachments that would impair the ability of the water course to carry and discharge the waters resulting from the 100 year flood.

Prior to the construction of any new or substantial improvements of structures or the establishment of any use, other than agriculture, on a parcel of land affected by a water course, the following requirements must be satisfied:

a.

A flood control facility to accommodate the 100 year flood plus one foot freeboard shall be designed and constructed in accordance with city standards and to the satisfaction of the City Engineer.

b.

An easement of adequate width to accommodate the flood channel, together with a 10′ wide access road shall be granted to the City of La Mesa, if the city accepts the maintenance of such facility.

A property owner shall submit detailed plans for development of the property showing proposed grading, vehicular access, parking areas, proposed land use, floor elevation and location of buildings together with a recommended proposal for necessary flood control facilities. If it is demonstrated to the satisfaction of the City Engineer that it would be an advantage to the property owner to delay actual construction of the flood control facility and such delay would not create hazards to adjacent property or to persons in the area, the City Engineer may recommend to the City Council and the City Council may accept a performance bond or other improvement security to guarantee the installation of such facility.