§ 106.30.040. Creekside Development and Flood Hazard Mitigation

A.

Purpose. This Section provides standards that are intended to:

1.

Protect the natural, scenic, and recreational value of waterway and riparian resources within the City, including the provision of adequate buffer areas between creeks and adjacent development;

2.

Ensure that development either avoids areas subject to inundation by a 100-year flood or more frequent flooding event, or is located and/or designed and protected so that it will not be damaged by flooding, or increase the hazard of flooding on other properties;

3.

Protect new development from erosion caused by the meandering nature of the creek system; and

4.

Protect the water quality of the creeks.

B.

Applicability. The requirements of this Section apply to:

1.

Creekside properties. Proposed development, other than public works or infrastructure, on any site adjacent to or crossed by a watercourse that is shown on the map in Figure 3-1; and

2.

Properties within areas subject to flooding. All properties shown on the Flood Insurance Rate Maps (FIRM) prepared by the Federal Emergency Management Agency (FEMA) as being partly or entirely located in an area subject to flooding by a 100-year flood or more frequent flooding event, and other areas known to the City to be subject to flooding. These areas shall be referred to in this Section as "flood hazard areas."

C.

Streambed analysis required. A planning permit application for a project subject to this Section shall include a site-specific streambed analysis prepared by a hydrologist, civil engineer, or other qualified professional approved by the City to identify the precise boundary/top of bank of the waterway. The Director may waive this requirement if it is determined that the project, because of its size, location, or design will not have a significant impact on the waterway, or that sufficient information already exists and further analysis is not necessary. A required streambed analysis shall include all information and materials required by the Department and/or the City Engineer.

D.

Subdivision requirements. Each new parcel proposed adjacent to a designated tributary shall be designed to provide the lot area shown in the following table for the applicable zone, located outside the 100-year floodplain of the tributary.

Zoning District	Minimum Net Lot Area
RD-1	0.50 acres
RD-2	0.25 acres
RD-3, RD-4	7,500 sf
RD-5, RD-7	Entire lot or 5,000 sf, whichever is less
RD-10 and above	Entire area except for common open space and landscape areas
Commercial and Industrial zones	Entire area except for landscaping

 

E.

Development standards.

1.

Location of proposed development. Proposed structures and other development shall comply with the more restrictive of the following requirements.

a.

Creek setback for resource preservation. Each proposed structure shall be set back a distance of 2.5 times the height of the stream bank plus 30 feet, or 30 feet outward from the stream bank, whichever distance is greater, as measured from the top of the stream bank outward.

(1)

The City may require additional setbacks to preserve existing vegetation or other significant environmental resources along any waterway.

(2)

The City may require erosion protection to be placed at creek bends, drainage outfalls, and other locations that are subject to erosion, or where bank steepness indicates that severe erosion is taking, or may take place.

(3)

A setback required by the applicable zoning district adjacent to a creekside path or open space area shall be measured from the boundary of the path or open space on the side away from the creek.

(4)

A path or trail may be located within a creekside setback; however, no structure, road, parking access, parking space, paved area, or swimming pool shall be constructed within a creek or creekside setback area.

b.

Limitations on development within floodplain. All construction, except fences, shall be located outside the 100-year floodplain of the tributary. The 100-year floodplain shall be established using the most current data available and a physical survey by a registered surveyor. Current data includes the Flood Insurance Rate Map, historical data from the 1986, 1995 and 1997 flood events, and the county hydrology study. Fences within a floodplain shall be limited to wrought iron or split rail design. No fill or grading shall be allowed within a 100-year floodplain. Where the review authority determines that an existing parcel contains no feasible building site outside of a 100-year floodplain and that the site complies with an exception outlined in the City's Drainage and Development Policy, the review authority may approve construction that complies with the creek setback required by Subsection E.1.a.

2.

Standards for development allowed within floodplain. Any development allowed within a 100-year floodplain in compliance with this Section shall comply with the following standards, as applicable.

a.

Finished floor elevation. Each approved structure shall be designed to provide all habitable finished floor areas at least two feet above the maximum 100-year water surface elevation. The FEMA 100-year flood elevation may be considered as a minimum level. Historical data from the 1986, 1995 and 1997 flood events, the county hydrology study and other miscellaneous studies shall be used to determine if a higher minimum elevation is required. The venting under the home and venting for a garage shall comply with the standards of the National Flood Insurance Program.

b.

Fences, culverts, bridges, and drainage improvements.

(1)

Fences and other structures including culverts and bridges that must be constructed within a floodway shall be designed to the requirements of the Engineering Division to prevent obstructions or diversions of flood and drainage flow, and to minimize adverse effects to natural riparian vegetation.

(2)

Where drainage improvements are required, they shall be placed in the least visible locations and naturalized through the use of river rock, earthtone concrete, and landscaping with native plant materials.

c.

Anchorage. All new construction and substantial improvements shall be anchored to prevent flotation, collapse or lateral movement of the structure.

d.

Construction practices and materials. All new construction or substantial improvements shall be constructed with materials and utility equipment resistant to flood damage using methods and practices that minimize flood damage.

e.

Water and sewer systems. New and replacement water and sanitary sewage systems shall be designed to minimize or eliminate infiltration of floodwaters into the systems and discharges from the systems into floodwaters.

f.

Floodproofing. Each structure requiring floodproofing shall be designed in compliance with National Flood Insurance Program standards. A FEMA elevation certificate shall be obtained and filed with the City prior to occupancy. A registered professional engineer or architect shall certify compliance with the standards of this Section, and the Building Official shall be provided a copy of the certification.

3.

Alteration of natural features. No construction, grading or filling, planting of exotic/non-native or non-riparian plant species, or removal of native vegetation shall occur within a creek or creekside setback area, except where:

a.

Approved by the review authority in conjunction with an application for rezoning, and/or a planning permit, or through Use Permit approval if no other application has been filed; and

b.

Authorized for flood control purposes by the proper permits issued by the California State Department of Fish and Game, and all other applicable State and Federal agencies having authority over the creek.

4.

Use of permeable surfaces. Proposed development should incorporate permeable surfaces (for example, wood decks, sand-joined bricks, and stone walkways) where feasible, to minimize off-site flows and facilitate the absorption of water into the ground.

5.

Creek bank stabilization. Development or land use changes that increase impervious surfaces or sedimentation may result in channel erosion. This may require measures to stabilize creek banks.

a.

Creek rehabilitation is the preferred method of stabilization, with the objective of maintaining the natural character of the creek and riparian area. Rehabilitation may include enlarging the channel at points of obstruction, clearing obstructions at points of constriction, limiting uses in areas of excessive erosion, and restoring riparian vegetation.

b.

Concrete channels are not allowed. Other mechanical stabilization measures shall not be allowed unless no other alternative exists.

c.

If bank stabilization requires other than rehabilitation or vegetative methods, hand-placed stone or rock rip-rap are the preferred methods.

6.

Physical and visual access.

a.

Public access and visibility to creeks should be provided, if feasible, through the use of single-loaded frontage roads adjacent to creeks, but outside of the creek setback. Structures or lots that back-up to creeks or creek frontage roads are discouraged.

b.

The provision of multipurpose creekside trails and public open space is encouraged. Open space areas should include planting for riparian enhancement with native shrubs and trees, paths and trails, lighting, benches, play and exercise equipment, and trash receptacles outside of the riparian habitat area, where appropriate.

c.

Where streets are not used, frequent access to creekside trails and public open space should be provided at least every 300 feet, and may occur at the end of cul-de-sacs.

7.

Best management practices (BMPs) for storm water quality. Development along creekside areas shall be designed to minimize impacts to storm water quality.

a.

Drainage swales and runoff should be filtered through grassy swales or other BMPs acceptable to the City Engineer to remove street oils, sediments and other site specific storm water environmental hazards.

b.

Fertilizer or pesticide usage is discouraged. Plants and trees for landscape areas should be selected that can survive without fertilizers or pesticides. Long-term ponding of water from landscape irrigation shall be avoided.

c.

Retention/detention basins will require mosquito abatement.

F.

Warning - Liability denied. The degree of flood protection required by this Section is considered reasonable for regulatory purposes and is based on scientific and engineering considerations. Larger floods can and will occur on rare occasions. Flood heights may be increased by manmade or natural causes. This Section does not imply that land outside the areas of special flood hazards or uses permitted within the areas will be free from flooding or flood damages. This Section shall not create liability on the part of the City or by any officer or employee for any flood damages that result from reliance on this Section or any administrative decision lawfully made under this Section.

(Ord. No. 2008-15, § 1, 12-11-2008)