Chapter 18.34 - Flood Plain Management

Sections:

18.34.010 - Purpose of Chapter
18.34.020 - Applicability
18.34.030 - Definitions
18.34.040 - Warning and Disclaimer of Liability
18.34.050 - Variance Required
18.34.060 - General Provisions
18.34.070 - Provisions for Flood Hazard Reduction
18.34.080 - Consideration for Variances
18.34.090 - Conditions for Variance Issuance

18.34.010 - Purpose of Chapter

A. This Chapter provides regulations for development within areas of potential flood hazard to:

1. Protect, conserve, and promote the orderly development of land and water resources;

2. Protect human life and health;

3. Minimize expenditure of public money for costly flood control projects;

4. Minimize the need for rescue and relief efforts associated with flooding;

5. Minimize prolonged business interruptions;

6. Minimize damage to public facilities and utilities;

7. Insure that potential buyers are notified that property is in an area of special flood hazard;

8. Insure that those who occupy areas of special flood hazard assume responsibility for their actions;

9. Preserve the natural hydrologic and hydraulic functions of watercourses and flood plains, and protect water quality and aquatic habitats; and

10. Preserve the natural characteristics of stream corridors in order to moderate flood and stormwater impacts, improve water quality, reduce soil erosion, protect aquatic and riparian habitat, provide recreational opportunities, provide aesthetic benefits, and enhance community and economic development.

B. In order to accomplish the above purpose, this Chapter includes methods and regulations for:

1. Restricting or prohibiting uses which are dangerous to health, safety and property due to water or erosion hazards, or which result in damaging increases in erosion or flood heights or velocities;

2. Requiring that uses vulnerable to floods, including facilities which serve the uses, be protected against flood damage at the time of initial construction;

3. Controlling the alteration of natural flood plains, stream channels, and natural protective barriers, which help accommodate or channel flood waters;

4. Controlling filling, grading, dredging and other development which may increase flood damage; and

5. Preventing or regulating the construction of flood barriers which will unnaturally divert flood waters or which may increase flood hazards in other areas.

18.34.020 - Applicability

The regulations of this Chapter shall apply to all areas of special flood hazard identified by the Federal Emergency Management Agency (FEMA) or the Federal Insurance Administration (FIA) in a report entitled "Flood Insurance Study for Nevada County, California Unincorporated Areas" dated July 2, 1987, with an accompanying Flood Insurance Rate Map with map index dated July 2, 1987 or any subsequent revisions or amendments. The report is adopted by reference and is part of this Chapter. The Flood Insurance Study is on file at the Department. The Flood Insurance Study and Flood Insurance Rate Map are the minimum area of applicability of this Chapter and may be supplemented by studies for other areas which allow implementation of this Chapter.

Uses shall not be established and structures shall not be constructed, located, extended, converted or altered without full compliance with the requirements of this Chapter and other applicable regulations of this Development Code. Docks, piers, ramps, and similar structures within the 100-year floodplain of Donner Lake shall be exempt from the provisions of this Chapter if constructed in compliance with Section 18.38.050(D) and approvals are obtained from all agencies with permitting authority.

18.34.030 - Definitions

The following are definitions of special terms and phrases used in this Chapter. Other general definitions are provided in Chapter 18.220 (Definitions/Glossary).

Encroachment. The advance or infringement of uses, plant growth, fill, excavation, permanent structures, or development into a floodplain which may impede or alter the flow capacity of a floodplain.

Fraud and victimization. As related to Section 18.34.080 (Consideration for Variances), the granting of the variance will not cause fraud on or victimization of the public. In examining this requirement, the Zoning Administrator will consider the fact that every new structure adds to government responsibilities and remains a part of the community for 50 to 100 years. Structures that are permitted to be constructed below the base flood elevation are subject during all those years to increased risk of damage from floods, while future owners of the property and the community as a whole are subject to all the costs, inconvenience, danger, and suffering that those increased flood damages bring. In addition, future owners may purchase the property, unaware that it is subject to potential flood damage, and can be insured only at very high flood insurance rates.

Functionally dependent. A use that cannot perform its intended purpose unless it is located or carried out in close proximity to water. This term includes only piers and other docking and port facilities that are necessary for the loading and unloading of cargo or passengers and the seasonal mooring of boats and other watercraft. It does not include long-term storage or related manufacturing facilities.

Hardship. As related to Section 18.34.080 (Consideration for Variances), the exceptional hardship that would result from a failure to grant the requested variance. The Zoning Administrator requires that the variance be exceptional, unusual, and peculiar to the property involved. Mere economic or financial hardship alone is not exceptional. Inconvenience, aesthetic considerations, physical handicaps, personal preferences, or the disapproval of one's neighbors likewise cannot, as a rule, qualify as an exceptional hardship. All of these problems can be resolved through other means without granting a variance, even if the alternative is more expensive, or requires the property owner to build elsewhere or put the parcel to a different use than originally intended.

Lowest floor. The lowest floor of the lowest enclosed area (including basement) . An unfinished or flood resistant enclosure, useable solely for parking of vehicles, building access or storage in an area other than a basement area, is not considered a structure's lowest floor; provided, that the enclosure is not built so as to render the structure in violation of the applicable non-elevation design requirements of this Chapter. For residential structures, all subgrade enclosed areas are prohibited as they are considered to be basements. This prohibition includes below-grade garages and storage areas.

New construction. For floodplain management purposes, structures for which the start of construction commenced on or after August 1, 1988, and includes any subsequent improvements to these structures.

Obstruction. Includes, but is not limited to, any dam, wall, wharf, embankment, levee, dike, pile, abutment, protection, excavation, channelization, bridge, conduit, culvert, building, wire, fence, rock, gravel, refuse, fill, structure, vegetation or other material in, along, across or projecting into any watercourse which may alter, impede, retard or change the direction and/or velocity of the flow of water, or due to its location, its propensity to snare or collect debris carried by the flow of water, or its likelihood of being carried downstream.

Public safety and nuisance. As related to Section 18.34.080 (Consideration for Variances), the granting of a variance must not result in anything that is injurious to safety or health of an entire community or neighborhood, or any considerable number of persons, or unlawfully obstructs the free passage or use, in the customary manner, of any navigable lake, or river, bay, stream, canal, or basin.

Start of construction. Start of construction includes substantial improvement and other proposed new development and means the date the building permit was issued, provided the actual start of construction, repair, reconstruction, rehabilitation, addition, placement, or other improvement was within 180 days from the date of the permit. The actual start means either the first placement of permanent construction of a structure on a site, (e.g., pouring of slab or footings, installation of piles, construction of columns) or any work beyond the stage of excavation, or the placement of a manufacture home on a foundation. Permanent construction does not include land preparation, (e.g., clearing, grading, and filling) nor does it include the installation of streets and/or walkways; nor does it include excavation for a basement, footings, piers, or foundations or the erection of temporary forms; nor does it include the installation of accessory buildings, (e.g., garages or sheds) not occupied as dwelling units or not part of the main structure. For a substantial improvement, the actual start of construction means the first alteration of any wall, ceiling, floor, or other structural part of a building, whether or not that alteration affects the external dimensions of the building.

Substantial damage. Damage of any origin sustained by a structure whereby the cost of restoring the structure to its before damaged condition would equal or exceed 50 percent of the market value of the structure before the damage occurred.

Substantial improvement. Any reconstruction, rehabilitation, addition, or other proposed new development of a structure, the cost of which equals or exceeds 50 percent of the market value of the structure before the start of construction of the improvement. This term includes structures which have incurred substantial damage, regardless of the actual repair work performed. The term does not include either:

a. Any project for improvement of a structure to correct existing violations or state or local health, sanitary, or safety code specifications which have been identified by the Chief Building Official and which are the necessary to assure safe living conditions; or

b. Any alteration of a historic structure, provided the alteration will not preclude the structure's continued designation as a historic structure.

After August 1, 1988, the value of any work to be performed under a building permit issued after that date shall be compared to the total value of the structure at the time of the permit application to calculate the percentage of new construction, additions or repairs, under the permit. This percentage figure shall be added to any successive building permits that may be issued within a subsequent five year span. If the percentage of construction work performed under the successive building permit totals 50 percent or more, this work shall constitute a substantial improvement. If a structure undergoes substantial improvements, the entire structure shall comply with the provisions of this Chapter.

18.34.040 - Warning and Disclaimer of Liability

The degree of flood protection required by this Chapter 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 man-made or natural causes. This Chapter does not imply that land outside the areas of special flood hazards, or uses permitted within these areas will be free from flooding or flood damages. This Chapter shall not create liability on the part of the Town, any officer or employee thereof, the Federal Insurance Administration, Federal Emergency Management Agency, or the State of California, for flood damages that result from reliance on this Chapter or any an administrative decision lawfully made thereunder.

18.34.050 - Variance Required

A. When required. A Variance (Chapter 18.82) shall be obtained before any construction or other development (not including trails, paths and sidewalks) begins within an area of special flood hazard. Grading or filling performed in the course of soil stabilization or erosion control measures for improvements in place as of the effective date of this Development Code may be allowed with Building Permit approval.

B. Exempt work. A Variance shall not be required for grading or filling performed in the course of providing soil stabilization or erosion control measures for improvements that were in place as of the effective date of this Development Code or for the construction of docks and associated grading subject to the development standards for docks and approval by the Lahontan Regional Water Quality Control Board.

C. Application content. A Variance application shall include the forms furnished by the Department and may include plans in duplicate drawn to scale showing the nature, location, dimensions, and elevation of the area in question, existing or proposed structures, fill, storage of material, drainage facilities, and the location of the foregoing. An application for a variance shall also include the following information:

1. Proposed elevation in relation to mean sea level, of the lowest floor (including basement) of all structures;

2. Proposed elevation in relation to mean sea level to which any structure will be flood proofed;

3. All appropriate certifications listed in Section 18.34.070 (Provisions for Flood Hazard Reduction); and

4. Description of the extent to which any watercourse will be altered or relocated as a result of proposed development.

18.34.060 - General Provisions

A. Use of other Base Flood Data. When base flood elevation data has not been provided, the Department shall obtain, review and utilize base flood elevation and floodway data available from a Federal, State or other source, in order to administer Section 18.34.070 (Provisions for Flood Hazard Reduction).

B. Notification. Whenever a watercourse is to be altered or relocated, the Department shall notify adjacent communities, the California Department of Water Resources, Federal Insurance Administration (FIA), and Federal Emergency Management Agency (FEMA) prior to the alteration or relocation, and submit evidence of the notification to FIA and FEMA.

C. Public records. The Department shall maintain the following information and certifications and make them available for public inspection:

1. Certification of lowest floor elevation in compliance with Section 18.34.070.A.3.a;

2. Certification of elevation or floodproofing of non-residential structures in compliance with Section 18.34.070.A.3.b;

3. Certification of designs to automatically equalize hydrostatic flood forces in compliance with Section 18.34.070.A.3.c;

4. Identification of flood hazard areas for proposed tentative maps in compliance with Section 18.34.070.C; and

5. Certification of no increase in flood levels in compliance with Section 18.34.070.E.1.

D. Map determinations. The Department shall make interpretations where needed, as to the exact location of the boundaries of the areas of special flood hazard, for example, where there appears to be a conflict between a mapped boundary and actual field conditions. The person contesting the location of the boundary shall be given a reasonable opportunity to appeal the interpretation. Grade elevation and the base flood elevation shall be used in determining the area of special flood hazard.

18.34.070 - Provisions for Flood Hazard Reduction

A. Standards for construction. In areas of special flood hazards, the following standards are required:

1. Anchoring.

a. New construction and substantial improvements shall be anchored to prevent flotation, collapse or lateral movement of the structure resulting from hydrodynamic and hydrostatic loads.

b. All manufactured homes shall meet the anchoring standards of Subsection D., below.

2. Construction materials and methods.

a. New construction and substantial improvements shall be constructed with materials and utility equipment resistant to flood damage.

b. New construction and substantial improvements shall be constructed using methods and practices that minimize flood damage.

c. New construction and substantial improvements shall be constructed with electrical, heating, ventilation, plumbing and air conditioning equipment and other service facilities that are designed and/or located to prevent water from entering or accumulating within the components during conditions of flooding.

3. Elevation and floodproofing

a. New construction and substantial improvement of a structure shall have the lowest floor, including basement, elevated one foot above the base flood elevation for all special flood hazard areas or zones. Non-residential structures may meet the standards in paragraph b. below. Upon the completion of the structure, the elevation of the lowest floor including basement shall be certified by a registered professional engineer or surveyor. The certification shall be provided to the Department.

b. Non-residential construction shall either be elevated in conformance with paragraph a. above or together with attendant utility and sanitary facilities:

(1) Be flood proofed so that below an elevation of one foot above the base flood level the structure is watertight with walls substantially impermeable to the passage of water;

(2) Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy; and

(3) Be certified by a registered professional engineer or architect that the standards of this subsection are satisfied. The certification shall be provided to the Department.

c. New construction and substantial improvements that have fully enclosed areas below the lowest floor that are subject to flooding shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwaters. Designs for meeting this requirement shall meet or exceed the following minimum criteria:

(1) Provide a minimum of two openings having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding. The bottom of all openings shall be no higher than one foot above finished grade. Openings may be equipped with screens, louvers, valves or other coverings or devices provided that they permit the automatic entry and exit of floodwaters; or

(2) Be certified by a registered professional engineer or architect to comply with the guidelines for engineered openings in FEMA Technical Bulletin 1-93.

B. Standards for utilities.

1. New and replacement water supply and sanitary sewage systems shall be designed to minimize or eliminate infiltration of flood waters into the system and discharge from systems into flood waters.

2. On-site waste disposal systems shall be located to avoid impairment to them or contamination from them during flooding.

C. Standards for subdivisions. All tentative map proposals shall identify the flood hazard area and the elevation of the base flood. A proposed subdivision shall not create or establish building sites, or pads within flood hazard areas. Roads, driveways, and utilities shall be designed to minimize flood damage.

D. Standards for manufactured homes. Manufactured homes and additions to manufactured homes shall:

1. Be elevated so that the lowest floor is one foot above the base flood elevation; and

2. Be securely anchored to a permanent foundation system to resist flotation, collapse or lateral movement.

E. Floodway. Floodways are located within special flood hazard areas and are extremely hazardous due to the velocity of flood waters which carry debris, potential projectiles, and erosion potential. The following provisions apply within floodways:

1. Encroachments, including fill, new construction, substantial improvements, and other development is prohibited unless certification by a registered professional engineer is provided demonstrating that encroachments shall not result in any increase in base flood elevations during the occurrence of the base flood discharge.

2. If paragraph 1. above is satisfied, new construction, substantial improvements, and other proposed new development shall comply with all other applicable flood hazard reduction provisions of this Section.

18.34.080 - Consideration for Variances

A. Application review considerations. In reviewing applications for Variances to the requirements of this Chapter, the Zoning Administrator shall consider all technical evaluations, relevant factors, standards specified in this Chapter, and the following:

1. The danger that materials may be swept onto other lands to the injury of others;

2. The danger of life and property due to flooding or erosion damage;

3. The susceptibility of the proposed facility and its contents to flood damage and the effect of damage on the individual owner;

4. The importance of the services provided by the proposed facility to the community;

5. The necessity to the facility of a waterfront location, where applicable;

6. The availability of alternative locations for the proposed use which are not subject to flooding or erosion damage;

7. The compatibility of the proposed use with existing and anticipated development;

8. The relationship of the proposed use to the comprehensive plan and flood plain management program for that area;

9. The safety of access to the property in time of flood for ordinary and emergency vehicles;

10. The expected heights, velocity, duration, rate of rise, and sediment transport of the flood waters expected at the site; and

11. The costs of providing governmental services during and after flood conditions, including maintenance and repair of public utilities and facilities (e.g., sewer, gas, electrical, and water system, and streets and bridges).

B. Findings for approval. In addition to the findings required for the approval of a Variance (Chapter 18.82), the following special findings are also required for development within special flood hazard areas:

1. A showing of good and sufficient cause;

2. A determination that failure to grant the Variance would deny the applicant the right to develop the property, and would result in exceptional hardship to the applicant;

3. A determination that the granting of a Variance will not result in additional threats to public safety, extraordinary public expense, create nuisances, cause fraud on or victimization of, the public, or conflict with existing local laws or ordinances;

4. All required State and federal permits have been or will be obtained;

5. The site is reasonably safe from flooding;

6. The environmental document prepared for the project complies with the requirements of the California Environmental Quality Act;

7. The proposed development complies with all applicable provisions of Section 18.34.070 (Provisions for Flood Hazard Reduction).

8. The proposed development does not adversely affect the carrying capacity of areas where base flood elevations have been determined, but a floodway has not been designated. For purposes of this Chapter, "adversely affects" means that the cumulative effect of the proposed development when combined with other existing and anticipated development will not increase the water surface elevation of the base flood more than one foot at any one point.

C. Conditions of approval. Upon consideration of the factors of Subsection A. above and the purposes of this Chapter, the Zoning Administrator may impose conditions to the granting of a Variance as it deems necessary to further the purposes of this Chapter.

D. Records and reporting. The Department shall maintain the records of all appeal actions and report any variances to the Federal Insurance Administration and Federal Emergency Management Agency upon request.

18.34.090 - Conditions for Variance Issuance

A. Variances may be issued for the reconstruction, rehabilitation or restoration of structures listed in the National Register of Historic Places, the State Inventory of Historic Places, or the Town of Truckee Historic Resources Inventory without regard to the procedures set forth in this Chapter upon a determination that the proposed repair or rehabilitation will not preclude the structure’s continued designation as an historic structure and the Variance is the minimum necessary to preserve the historic character and design of the structure.

B. Variances shall not be issued within any designated floodway if any increase in flood levels during the base flood discharge would result.

C. Variances shall only be issued upon a determination that the construction approved by the Variance is the minimum necessary, considering the flood hazard, to afford relief. "Minimum necessary" means to afford relief with a minimum of deviation from the requirements. For example, in the case of Variances to an elevation requirement, this means the Zoning Administrator need not grant permission for the applicant to build at grade, or even to whatever elevation the applicant proposes, but only to that elevation which the Zoning Administrator believes will both provide relief and preserve the integrity of these regulations.

D. Variances may be issued for new construction and substantial improvements and for other development necessary for the conduct of a functionally dependent use provided that the provisions of Subsections A. through C. above are satisfied, and that the structure or other development is protected by methods that minimize flood damages during the base flood and create no additional threats to public safety.

E. Any applicant to whom a Variance is granted shall be given written notice that the issuance of a Variance to construct a structure below the base flood elevation will result in increased premium rates for flood insurance commensurate with the increased risk resulting from the reduced lowest floor elevation (up to $25 for each $100 of insurance coverage) and that any construction below the regulatory flood elevation increases risks to life and property. A copy of the notice shall be recorded in the office of the Nevada County Recorder and shall be recorded in a manner so that it appears in the chain of title of the affected parcel of land.