Note: Prior ordinance history: Ords. 767, 837, 939, 1079, 1094, 1176, 1239, 1249.
The Legislature of the State of California has in Government Code Sections 65302, 65560, and 65800 conferred upon local government units authority to adopt regulations designed to promote the public health, safety, and general welfare of its citizenry. Therefore, the City Council of the City of Mill Valley does hereby adopt the following floodplain management regulations.
(Ord. 1257 § 2, October 15, 2012)
A. 
Mill Valley tidelands, shorelines, waterways, beaches, mudflats and salt marshes are vital, natural resources which provide great benefits to present and future human generations. In addition to assisting the process of converting carbon dioxide to oxygen, they are essential features of the environment which not only provide food chains and serve as habitat for marine and bird life but are also, because of the unique part-time exposure to air, the only locations where certain fish eggs, larvae and other forms of life can develop. They provide one of a few remaining examples of natural seasonal growth and plant succession in the Bay Area. They provide protection against erosion during storm conditions and, if left undisturbed, a natural drainage system. They fulfill an indispensable role in preserving our temperate climate and the air purity of the Bay Area. They offer scenic views, open space, recreational opportunities such as fishing, swimming, boating, walking, picnicking, nature study and facilities for water transportation. But most important, they function as a delicately balanced biological system. The impact of man-made changes in one place is felt throughout the whole system and is not confined by property lines or other artificial boundaries. These benefits could be destroyed or seriously diminished by uncontrolled or haphazard conduct which is inimical to the welfare of both present and future residents of Mill Valley. Therefore, the tidelands, shorelines, waterways, beaches, mudflats, and salt marshes, together with all those areas designated elsewhere in this chapter, must be subject to proper controls for the preservation of these lands in their natural state so that these benefits may endure.
B. 
The flood hazard areas of Mill Valley are subject to periodic inundation which results in loss of life and property, disruption of commerce and governmental services, health and safety hazards, extraordinary public expenditures for flood protection and relief, and impairment of the tax base, all of which adversely affect the public health, safety and general welfare.
C. 
These flood losses are caused by the cumulative effect of obstructions in flood hazard areas causing increased flood heights and erosive velocities and the occupancy of flood hazard areas by uses vulnerable to floods which are inadequately elevated or otherwise protected from flood damages.
D. 
The regulatory flood area selected for this chapter is representative of major floods known to have occurred in Mill Valley and which are reasonably characteristic of what can be expected to occur in the future. The chances of such flooding can be expected to occur with a one percent frequency in any one year.
(Ord. 1257 § 2, October 15, 2012)
It is therefore the intention of the City Council and the purpose of this chapter to ensure the survival of these vital natural resources to protect and preserve essential elements of the environment, to maintain these benefits with a minimum of physical disturbance, to set forth the standards and procedures by which filling, excavating, mining and all other construction in the designated areas will be regulated and to promote the public health, safety, and general welfare and to minimize public and private losses due to flood conditions in specific areas by provisions designed to:
A. 
Protect human life and health.
B. 
Minimize expenditure of public money for costly flood control projects.
C. 
Minimize the need for rescue and relief efforts associated with flooding and generally undertaken at the expense of the general public.
D. 
Minimize prolonged business interruptions.
E. 
Minimize damage to public facilities and utilities such as water and gas mains; electric, telephone and sewer lines; and streets and bridges located in areas of special flood hazard.
F. 
Help maintain a stable tax base by providing for the sound use and development of areas of special flood hazard so as to minimize future blighted areas caused by flood damage.
G. 
Ensure that potential buyers are notified that property is in an area of special flood hazard.
H. 
Ensure that those who occupy the areas of special flood hazard assume responsibility for their actions.
I. 
Restrict or prohibit uses which are dangerous to health, safety, or property in times of flood or which cause excessive increases in flood heights or velocities.
J. 
Require that uses vulnerable to floods, including facilities which serve such uses, be protected against flood damage at the time of initial construction.
K. 
Control filling, grading, dredging, and other development which may increase flood damage.
(Ord. 1257 § 2, October 15, 2012)
Unless specifically defined in this section, words or phrases used in this chapter shall be interpreted so as to give them the same meaning as they have in common usage and so as to give this chapter its most reasonable application.
"Accessory structure"
means a structure that is either:
a. 
Solely for the parking of no more than two cars; or
b. 
A small, low cost shed for limited storage, less than 150 square feet and $1,500.00 in value.
"Accessory use"
means a use which is incidental and subordinate to the principal use of the parcel of land on which it is located.
"Alluvial fan"
means a geomorphologic feature characterized by a cone or fan-shaped deposit of boulders, gravel, and fine sediments that have been eroded from mountain slopes, transported by flood flows, and then deposited on the valley floors, and which is subject to flash flooding, high velocity flows, debris flows, erosion, sediment movement and deposition, and channel migration.
"Apex"
means the point of highest elevation on an alluvial fan, which on undisturbed fans is generally the point where the major stream that formed the fan emerges from the mountain front.
"Appeal"
means a request for a review of the Floodplain Administrator's interpretation of any provision of this chapter or a request for a variance.
"Area of shallow flooding"
means a designated AO zone on the Flood Insurance Rate Map (FIRM). The base flood depths range from one to three feet; a clearly defined channel does not exist; the path of flooding is unpredictable and indeterminate, and velocity flow may be evident. Such flooding is characterized by ponding or sheet flow.
"Area of special flood hazard"
- See "Special flood hazard area."
"Base flood"
means a flood which has a one percent chance of being equaled or exceeded in any given year (also called a 100-year flood). Base flood is the term used throughout this chapter.
"Base flood elevation"
means the elevation shown on the Flood Insurance Rate Map for zone AE that indicates the water surface elevation resulting from a flood that has a one percent or greater chance of being equaled or exceeded in any given year.
"Basement"
means any area of the building having a floor subgrade (below ground level) on all sides.
"Building"
– See "Structure."
"Depreciated market value"
means the value of the structure only and does not include the land or any other accessory buildings or site improvements. It is the replacement cost of the existing structure less any depreciation that results from age or condition. This is the condition of the existing structure that is reflected in an appraisal prepared by an independent professional appraiser and submitted to the Building Official prior to issuance of building permits. To establish the value of any proposed improvements, a contractor shall submit an itemized breakdown of estimated material/labor costs and, prior to issuance of building permits, a signed contract with the property owner to do the improvements for a specified price.
"Development"
means any man-made change to improved or unimproved real estate, including, but not limited to, buildings or other structures, mining, dredging, filling, grading, paving, excavation or drilling operations, manufactured home parks or subdivisions, or storage of equipment or materials.
"Encroachment"
means the advance or infringement of uses, plant growth, fill, excavation, buildings, permanent structures or development into a floodplain which may impede or alter the flow capacity of a floodplain.
"Flood," "flooding" or "flood water"
means a general and temporary condition of partial or complete inundation of normally dry land areas from the overflow of inland or tidal waters and/or the unusual and rapid accumulation of runoff of surface waters.
"Flood Insurance Rate Map (FIRM)"
means the most current official map prepared by the Federal Insurance Administration on file with the Planning and Building Department, which identifies the areas of special flood hazard within the City of Mill Valley.
"Flood Insurance Study"
means the official report provided the Federal Insurance Administration that includes flood profiles, the Flood Insurance Rate Map, Flood Boundary, Floodway Map, and the water surface elevation of the base flood.
"Floodplain" or "flood prone area"
means any land area susceptible to be inundated by water from any source. (See definition of flooding.)
"Floodplain Administrator"
means the Director of Planning and Building, or his/her designee.
"Floodplain management"
means the operation of an overall program of corrective and preventive measures for reducing flood damage including, but not limited to, emergency preparedness plans, flood control works, and floodplain management regulations.
"Floodplain management regulations"
means zoning ordinances, subdivision regulations, building codes, health regulations, special purpose ordinances (such as the Floodplain Ordinance, Grading Ordinance, and Erosion Control Ordinance) and other applications of police power. The term describes such state or local regulations in any combination thereof which provide standards for the purpose of flood damage prevention and reduction.
"Floodproofing"
means any combination of structural and nonstructural additions, changes, or adjustments to nonresidential structures which reduce or eliminate flood damage to real estate or improved real estate, water and sanitary facilities, structures, and their contents. Structural components shall have the capability of resisting hydrostatic and hydrodynamic loads and the effect of buoyancy.
"Floodway"
means the channel of a river or other watercourse and adjacent land area that must be reserved in order to discharge the base flood without cumulatively increasing the surface water elevation more than one foot. Also referred to as regulatory floodway.
"Floodway fringe"
is that area of the floodplain on either side of the "regulatory floodway" where encroachment may be permitted.
"Fraud and victimization"
as related to Section 18.04.130, Variances, of this chapter means that the variance granted must not cause fraud on or victimization of the public. In examining this requirement, the City of Mill Valley will consider the fact that every newly constructed building adds to government responsibilities and remains a part of the community for 50 to 100 years. Buildings 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.
"Governing body"
is the local governing body unit—i.e., the City of Mill Valley—that is empowered to adopt and implement regulations to provide for the public health, safety and general welfare of the citizenry.
"Hardship"
as related to Section 18.04.130, Variances, of this chapter means the exceptional hardship that would result from a failure to grant the requested variance. The City of Mill Valley requires that the variance be exceptional, unusual or 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.
"Highest adjacent grade"
means the highest natural elevation of the ground surface prior to construction next to the proposed walls of a structure.
"Historic structure"
means any structure that is:
a. 
Listed individually in the National Register of Historic Places (a listing maintained by the Department of Interior) or preliminarily determined by the Secretary of the Interior as meeting the requirements for individual listing on the National Register;
b. 
Certified or preliminarily determined by the Secretary of the Interior as contributing to the historical significance of a registered historic district or a district preliminarily determined by the Secretary to qualify as a registered historic district;
c. 
Individually listed on a state inventory of historic places in states with historic preservation programs which have been approved by the Secretary of the Interior; or
d. 
Individually listed on a local inventory of historic places in communities with historic preservation programs that have been certified either by an approved state program as determined by the Secretary of the Interior or directly by the Secretary of the Interior in states with approved programs.
"Lowest floor"
means the lowest floor of the lowest enclosed area including a basement (see basement definition). An unfinished or flood resistant enclosure below the lowest floor that is usable solely for parking of vehicles, building access or storage in an area other than a basement area, is not considered a building's lowest floor provided it conforms to applicable non-elevation design requirements, including, but not limited to, those specified in Section 18.04.100, Standards of construction.
"Manufactured home"
means a structure, transportable in one or more sections, which is built on a permanent chassis and is designed for use with or without permanent foundation when connected to the required utilities. For floodplain management purposes, the term "manufactured home" also includes park trailers and travel trailers and other similar vehicles placed on a site greater than 180 consecutive days.
"Market value"
means the replacement cost of an improvement less any depreciation that results from age or condition of the improvements. For purposes of this chapter, "market value" and "depreciated market value" have the same meaning. Market value of a structure excludes the value of the land, landscaping or detached accessory structures, as defined herein on the property. It is the property owner's responsibility to submit evidence establishing the market value of an existing or pre-damaged structure for review and approval by the Floodplain Administrator. Market value shall be determined by estimating the cost to replace the structure in new condition and adjusting that cost figure by the amount of depreciation which has accrued since the structure was constructed.
a. 
The cost of replacement of the structure shall be based on a square foot cost factor determined by reference to a building cost estimating guide recognized by the building construction industry.
b. 
The amount of depreciation shall be determined by taking into account the age and physical deterioration of the structure and functional obsolescence as approved by the floodplain administrator, but shall not include economic or other forms of external obsolescence.
Use of replacement costs or accrued depreciation factors different from those contained in recognized building cost estimating guides may be considered only if such factors are included in a report prepared by an independent professional appraiser and supported by a written explanation of the differences.
"Mean sea level"
means, for purposes of the National Flood Insurance Program, the National Geodetic Vertical Datum (NGVD) of 1929, North American Vertical Datum (NAVD) of 1998, or other datum, to which base flood elevation is shown on the community's Flood Insurance Rate Map are referenced.
"New construction"
means structures for which the "start of construction" commenced on or after the effective date of this chapter and includes any subsequent improvements to such structures. The lowest floor of a new structure shall be a minimum of one foot above the base flood elevation.
"Non-substantial or minor improvement"
means an improvement (including an addition, conversion or rehabilitation) that is valued at less than 50% of the depreciated market value of the existing structure. The lowest floor of an existing structure does not have to conform with the Mill Valley Floodplain Management Ordinance in connection with non-substantial or minor improvements to an existing structure.
"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.
"One hundred year flood"
means a flood which has a one percent annual probability of being equaled or exceeded. It is identical to the "base flood" which will be the term used throughout this chapter.
"Permanent construction"
does not include land clearing or filling; nor does it include the installation of streets and/or walkways; nor does it include the installation on the property of accessory buildings, such as garages or sheds not occupied as dwelling units or not as part of the main structure.
"Public safety and nuisance"
as related to Section 18.04.130, Variances, means that the granting of a variance must not result in anything which is injurious to the 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, river, bay, stream, canal, or basin.
"Public service facilities"
means any facilities installed by a governmental entity or an entity regulated by the Public Utilities Commission of the State of California and used or intended to be used to provide water, gas, electric or communication service and any pipelines and appurtenant facilities for the collection or transmission of sewage, floodwaters or stormwaters, petroleum, gas or any liquid substance.
"Recreational vehicle"
means a vehicle which is:
a. 
Built on a single chassis;
b. 
Four hundred square feet or less when measured at the largest horizontal projection;
c. 
Designed to be self-propelled or permanently towable by a light-duty truck; and
d. 
Designed primarily not for use as a permanent dwelling but as temporary living quarters for recreational, camping, travel or seasonal use.
"Regulatory floodway"
means the channel of a river or other watercourse and the adjacent land areas that must be reserved in order to discharge the base flood without cumulatively increasing the water surface elevation more than one foot.
"Remedy of violation"
means to bring the structure or other development into compliance with state or local floodplain management regulations or, if this is not possible, to reduce the impacts of its noncompliance. Ways that impacts may be reduced include protecting the structure or other affected development from flood damages, implementing the enforcement provisions of this chapter, or otherwise deterring future similar violations; or reducing federal financial exposure with regard to the structure or other development.
"Riverine"
means relating to, formed by, or resembling a river (including tributaries), stream, brook, etc.
"Sheet flow area"
- See "Area of shallow flooding."
"Special flood hazard area (SFHA)"
means the land in the floodplain within Mill Valley that is subject to a one percent or greater chance of flooding in any given year. Such areas are identified on the Flood Insurance Rate Map or FHBM on file with the City of Mill Valley and are further identified as Zone A, A0, A1-A30, AE, or A99.
"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, such as the pouring of slab or footings, the installation of piles, the 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, such as 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 on the property of accessory buildings, such as 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.
"Structure"
means a walled and roofed building that is principally above ground; this includes a gas or liquid storage tank or a manufactured home.
"Substantial damage"
means:
a. 
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% of the market value of the structure before the damage occurred; or
b. 
Flood-related damages sustained by a structure on two separate occasions during a 10-year period for which the cost of repairs at the time of each such event, on the average, equals or exceeds 25% of the market value of the structure before the damage occurred. This is also known as "repetitive loss."
"Substantial improvement"
means any repair, remodel, rehabilitation, addition, or improvement within a two-year time period, the cost of which equals or exceeds 50% of the "depreciated market" value of the existing structure either, before the improvement is started, or if the structure has been damaged and is being restored, before the damage occurred. In instances where there has been substantial damage in the absence of an appraisal, the "depreciated market value" of a structure shall be established by the property owner and approved by the Floodplain Administrator through use of a combination of the latest Marin County Assessor rolls, qualified estimates of the actual cash value of the structure provided by a licensed contractor, a licensed appraisal containing the value(s) of other comparable houses in the neighborhood or any other improvement estimate accepted by the Floodplain Administrator. 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 the building commences, whether or not that alteration affects the external dimensions of the structure. The costs of improvements required to comply with existing state or local health, sanitary, building or safety codes or regulations, or any alteration of a structure listed on the National Register of Historic Places or any state designation of historic places may be excluded from the total construction/improvement cost.
"Tidelands"
means those areas below the highest tide line as established by the San Francisco Bay Conservation and Development Commission for the Richardson Bay shoreline.
"Variance"
means a grant of release from the requirements of this chapter which permits construction in a manner that would otherwise be prohibited by this chapter.
"Violation"
means the failure of a structure or other development to be fully compliant with the community's floodplain management regulations. A structure or other development without the elevation certificate, or certifications, or other evidence of compliance required in this chapter is presumed to be in violation until such time as that documentation is provided.
"Water surface elevation"
means the height, in relation to the National Geodetic Vertical Datum (NGVD) of 1929, (or other datum, where specified) of floods of various magnitudes and frequencies in the floodplains of coastal or riverine areas.
"Watercourse"
means a lake, river, creek, stream, wash, arroyo, channel or other topographic feature on or over which waters flow at least periodically. Watercourse includes specifically designated areas in which substantial flood damage may occur.
(Ord. 1257 § 2, October 15, 2012)
A. 
This chapter shall apply to all lands within the jurisdiction of the City of Mill Valley that are identified as areas of special flood hazard.
B. 
The areas of special flood hazard identified by the Federal Emergency Management Agency (FEMA) in the most current "Flood Insurance Study (FIS) for the City of Mill Valley" on file with the Planning and Building Department with accompanying Flood Insurance Rate Map (FIRMs) and Flood Boundary and Floodway Maps (FBFMs), dated and all subsequent amendments and/or revisions, are hereby adopted by reference and declared to be a part of this chapter. This FIS and attendant mapping is the minimum area of applicability of this chapter and may be supplemented by studies for other areas which allow implementation of this chapter and which are recommended to the Mill Valley City Council by the Floodplain Administrator. The study, FIRMs and FBFMs are on file at the City of Mill Valley City Hall, 26 Corte Madera Avenue, Mill Valley, CA.
C. 
No structure or land shall hereafter be constructed, located, extended, converted or altered without full compliance with the terms of this chapter and other applicable regulations. Violation of the requirements (including violations of conditions and safeguards established in connection with conditions) shall constitute a misdemeanor. Nothing herein shall prevent the City of Mill Valley from taking such lawful action as is necessary to prevent or remedy any violation.
D. 
It is not intended by this chapter to repeal, abrogate, or impair any existing easement, covenants, or deed restrictions; however, where this chapter conflicts with other Mill Valley Municipal Code sections, resolutions, and/or ordinances, the most restrictive shall apply.
E. 
The degree of flood protection required by this chapter is considered reasonable for regulatory purposes and is based on engineering and scientific means of study. Larger floods may occur or flood heights may be increased by man-made or natural causes. This chapter does not imply that areas outside the areas of special flood hazard or land uses permitted within such areas will be free from flooding or flood damages. This chapter shall not create liability on the part of the City of Mill Valley or any officer or employee thereof, the State of California, the Federal Insurance Administration, or the Federal Emergency Management Agency for any damages that result from reliance on this chapter or any administrative decision made lawfully thereunder.
F. 
In the interpretation and application of this chapter, all provisions shall be:
1. 
Considered as minimum requirements;
2. 
Liberally construed in favor of the governing body;
3. 
Deemed neither to limit nor repeal any other powers granted under state statutes.
(Ord. 1257 § 2, October 15, 2012)
This chapter shall not apply in conditions set out in this section:
A. 
Any temporary emergency work necessary to prevent or minimize clear and present danger or damage to land or to existing legally permitted improvements from floodwaters. Such emergency work shall be reported in writing to the Director of Planning and Building within one working day after the start of such work and a permit application filed in accordance with Section 18.04.090. In the event the Floodplain Administrator determines that any work done pursuant to this exemption is in conflict with the standards set forth in this chapter, the Floodplain Administrator may require such temporary emergency work to be removed or may require such other adjustments therein as may be necessary to protect the public interest.
B. 
Any improvement to an existing structure that is considered to be "non-substantial or minor" (less than 50% of the depreciated market value of the existing structure) as defined in Section 18.04.040(35).
C. 
The owner or operator of any public service facility or a public street or road need not obtain a permit for construction. The public service facilities referred to in this section shall be limited to those which are necessary for and are customarily used to maintain existing services.
D. 
"Public service facilities" as used in this section means any facilities installed by a governmental entity or an entity regulated by the Public Utilities Commission of the State of California and used or intended to be used to provide water, gas, electric or communications service and any pipelines and appurtenant facilities for the collection or transmission of sewage, flood or stormwaters, petroleum, gas or any liquid substance.
E. 
Maintenance work, expansion or extension to legal conforming buildings or structures which comply with provisions of this chapter subject to continued compliance with the provisions of this chapter and any others that may apply.
F. 
Portions of a "pre-identified" building code violation or other "pre-identified latent construction defect" may be excluded from the total value of the improvement(s) when identified and approved by the Building Official before removal or replacement.
G. 
The value of any structural upgrade to a nonconforming structure that is necessary to comply with the Americans with Disabilities Act.
H. 
The reconstruction, rehabilitation, or restoration of historic structures as defined in Section 18.04.040(29), provided that the proposed repair or rehabilitation will not preclude the structure's continued designation as an historic structure and the reconstruction, rehabilitation, or restoration is the minimum necessary to preserve the historic character and design of the structure.
(Ord. 1257 § 2, October 15, 2012)
Upon receiving written notice from the City of Mill Valley that any development has taken place on any property in violation of the provisions of this chapter, the owner of the property shall immediately abate such development so as to leave such property in its natural condition to the satisfaction of the Floodplain Administrator.
(Ord. 1257 § 2, October 15, 2012)
A. 
The Director of Planning and Building is hereby appointed to administer, implement and enforce this chapter by granting or denying development permits in accord with the provisions of this chapter.
B. 
The duties and responsibilities of the Floodplain Administrator shall include, but not be limited to, the following:
1. 
Permit Review. Review all development permits to determine that:
a. 
Permit requirements of this chapter have been satisfied;
b. 
All other required state and federal permits have been obtained;
c. 
The site is reasonably safe from flooding;
d. 
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 the purpose of this chapter, "adversely affects" means that the cumulative effect of the proposed development when combined with all other existing and anticipated development will increase the water surface elevation of the base flood more than one foot at any point;
e. 
All letters of map revision (LOMRs) for flood control projects are approved prior to the issuance of building permits. Building permits must not be issued based on conditional letters of map revision (CLOMRs). Construction of the proposed flood control project and land preparation as specified in the "start of construction" definition are allowed under an approved CLOMR.
2. 
Development of Substantial Improvement and Substantial Damage Procedures.
a. 
Using FEMA publication FEMA 213, "Answers to Questions About Substantially Damaged Buildings," develop detailed procedures for identifying and administering requirements for substantial improvement and substantial damage, to include defining "market value."
b. 
Assure procedures are coordinated with other departments/divisions and implemented by community staff.
3. 
Review and Use of Any Other Base Flood Data. When base flood elevation data has not been provided as described in Section 18.04.050(B), the Floodplain Administrator shall obtain, review and reasonably utilize any base flood elevation and floodway data available from a federal agency, state agency, or FEMA publication to administer Section 18.04.100. Any such information shall be submitted to the City of Mill Valley for adoption.
4. 
Notification of Other Agencies. In alteration or relocation of a watercourse:
a. 
Notify adjacent communities and the California Department of Water Resources prior to alteration or relocation;
b. 
Submit evidence of such notification to the Federal Insurance Administration, Federal Emergency Management Agency; and
c. 
Assure that the flood carrying capacity within the altered or relocated portions of said watercourse is maintained.
5. 
Documentation of Floodplain Development. Obtain and maintain for public inspection and make available as needed the following:
a. 
Certification required by Section 18.04.100(D) (lowest floor elevations);
b. 
Certification required by Section 18.04.100(E) (elevation or floodproofing of nonresidential structures);
c. 
Certification required by Section 18.04.100(F) (wet floodproofing standard);
d. 
Certification of elevation required by Section 18.04.100(L) (subdivisions and other proposed development standards);
e. 
Certification required by Section 18.04.110(A) (floodway encroachments);
f. 
Maintain a record of all variance actions, including justification for their issuance, and report such variances issued in its biennial report submitted to the Federal Emergency Management Agency.
6. 
Map Determinations. 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 actual field conditions and the base flood elevation.
7. 
Remedial Action. Take action to remedy violations of this chapter as specified in Section 18.04.050(C).
8. 
All letters of map revision (LOMRs) for flood control projects shall be approved prior to the issuance of building permits. Building permits must not be issued based on conditional letters of map revision (CLOMRs). Construction of the proposed flood control project and land preparation as specified in the "start of construction" definition are allowed under an approved CLOMR.
9. 
Base flood elevation changes due to physical alterations:
a. 
Within six months of information becoming available or project completion, whichever comes first, the floodplain administrator shall submit or assure that the permit application submits technical or scientific data to FEMA for a letter of map revision (LOMR).
b. 
All LOMRs for flood control projects shall be approved prior to the issuance of building permits. Building permits shall not be issued based on conditional letters of map revision (CLOMRs). Construction of the proposed flood control project and land preparation as specified in the "start of construction" definition are allowed under an approved CLOMR.
i. 
Such submissions are necessary so that upon confirmation of those physical changes affecting flooding conditions, risk premium rates and floodplain management requirements are based on current data.
ii. 
Changes in corporate boundaries: FEMA shall be notified in writing whenever the corporate boundaries have been modified by annexation or other means and a copy of a map of the community clearly delineating the new corporate limits shall be included with the notice.
10. 
Planning. Assure community's General Plan is consistent with floodplain management objectives herein.
(Ord. 1257 § 2, October 15, 2012)
In addition to all development and building approvals, permits, or entitlements required by Titles 14, 20, or 21 of this Code, a development permit meeting the requirements of this chapter shall be obtained before any construction or other development, including manufactured homes, within any special flood hazard area established by Section 18.04.050(B). Application for a development permit under this chapter shall be made on forms furnished by the Planning and Building Department. The applicant shall provide the following information:
A. 
A "substantial improvement worksheet" accompanied by a current appraisal of the property (within 12 months of the date of application with the depreciated market value highlighted) and a detailed labor and material cost estimate from a licensed contractor, or other documentation of project value for the proposed work acceptable to the City.
B. 
All applicable certificates as listed in Section 18.04.080(B)(5).
C. 
Plans, drawn to scale, showing:
1. 
Location, dimensions, and elevation of the area in question, all existing or proposed structures, storage of materials and equipment and their location;
2. 
Existing and proposed locations of streets, easements, trees, water supply, sanitary sewer, and other utilities;
3. 
Grading information showing existing and proposed contours (contour intervals not more than five feet), any proposed fill, and drainage facilities;
4. 
Location of the regulatory floodway, when applicable;
5. 
Base flood elevation information as specified in Section 18.04.050(B);
6. 
Proposed elevation in relation to mean sea level, of the lowest floor (including basement) of all structures; and
7. 
Proposed elevation in relation to mean sea level to which any nonresidential structure will be floodproofed, as required in Section 18.04.100(E) of this chapter and detailed in FEMA Technical Bulletin TB 3-93.
D. 
For a crawl-space foundation, location and total net area of foundation openings as required in Section 18.04.100(F) of this chapter and detailed in FEMA Technical Bulletins 1-93 and 7-93.
E. 
Description of the extent to which any watercourse will be altered or relocated as a result of proposed development.
(Ord. 1257 § 2, October 15, 2012)
In all areas of special flood hazards the following standards are required:
A. 
All structures will be anchored to prevent flotation, collapse, or lateral movement of the structure resulting from hydrodynamic loads, including the effects of buoyancy.
B. 
All new construction and substantial improvements of structures, including manufactured homes, shall be constructed:
1. 
With flood resistant materials, and utility equipment resistant to flood damage for areas below the base flood elevation;
2. 
Using methods and practices that minimize flood damage;
3. 
With electrical, heating, ventilation, plumbing and air conditioning equipment and other service facilities that are designed and/or located so as to prevent water from entering or accumulating within the components during conditions of flooding;
4. 
With new or replacement water supply systems and sanitary disposal facilities that are designed and/or located to minimize or eliminate infiltration of flood waters into the system and discharge from the system into flood waters;
5. 
Within Zones AH or AO, so that there are adequate drainage paths around structures on slopes to guide flood waters around and away from proposed structures.
C. 
All methods and practices that minimize flood damage will be employed to the satisfaction of the Building Official and Floodplain Administrator.
D. 
All new residential construction or substantial improvements of residential structures shall have the lowest floor, including basement:
1. 
Elevated one foot above the base flood elevation in AE and AH zones;
2. 
Elevated above the highest adjacent grade of the building pad to a height equal to or exceeding one foot above the depth number specified in feet on the FIRM, or elevated at least two feet above the highest adjacent grade if no depth number is specified in AO zones.
Upon completion of the structure, the elevation of the lowest floor, including basement, shall be certified by a registered professional engineer or surveyor, and verified by the Floodplain Administrator to be properly elevated.
E. 
New construction or substantial improvement of any commercial, industrial or other nonresidential structure shall comply with one of the following requirements:
1. 
The lowest floor, including basement, elevated one foot above the base flood elevation in AE or AH zones; or
2. 
The lowest floor, including basement, shall be elevated above the highest adjacent grade of the building pad to a height equal to or exceeding one foot above the depth number specified in feet on the FIRM, or elevated at least two feet above the highest adjacent grade of the building pad if no depth is specified in an AO zone; or
3. 
Together with attendant utility and sanitary facilities, new or substantially improved commercial, industrial or other nonresidential structures shall:
a. 
Be floodproofed so that below the base flood level the structure is watertight with walls substantially impermeable to the passage of water;
b. 
Have structural components capable of resisting hydrostatic and hydrodynamic loads and effects of buoyancy;
c. 
Be certified by a registered professional engineer or architect that the standards of this subsection are satisfied.
F. 
All new construction and substantial improvements of structures with fully enclosed areas below the lowest floor (excluding basements) that are usable solely for parking of vehicles, building access or storage, and which are subject to flooding, shall be designed to automatically equalize hydrostatic flood forces on exterior walls by allowing for the entry and exit of floodwater. Designs for meeting this requirement must meet the following minimum criteria:
1. 
For non-engineered openings:
a. 
Have a minimum of two openings on different sides having a total net area of not less than one square inch for every square foot of enclosed area subject to flooding;
b. 
The bottom of all openings shall be no higher than one foot above grade;
c. 
Openings may be equipped with screens, louvers, valves or other coverings or devices provided that they permit the automatic entry and exit of floodwater; and
d. 
Buildings with more than one enclosed area must have openings on exterior walls for each area to allow flood water to directly enter; or
e. 
Be certified by a registered civil engineer or architect.
G. 
Detached Garages and Accessory Structures.
1. 
"Accessory structures" used solely for parking (two-car detached garages or smaller) or limited storage (small, low-cost sheds), as defined in Section 18.04.040(1), may be constructed such that its floor is below the base flood elevation (BFE), provided the structure is designed and constructed in accordance with the following requirements:
a. 
Use of the accessory structure must be limited to parking or limited storage;
b. 
The portions of the accessory structure located below the BFE must be built using flood-resistant materials;
c. 
The accessory structure must be adequately anchored to prevent flotation, collapse and lateral movement;
d. 
Any mechanical and utility equipment in the accessory structure must be elevated or floodproofed to or above the BFE;
e. 
The accessory structure must comply with floodplain encroachment provisions in Section 18.04.110; and
f. 
The accessory structure must be designed to allow for the automatic entry of flood waters in accordance with subsection F of this section.
2. 
Detached garages and accessory structures not meeting the above standards must be constructed in accordance with all applicable standards in Section 18.04.110.
H. 
All other required state and federal permits have been obtained.
I. 
All developments shall provide adequate drainage to reduce exposure to flood hazards.
J. 
All new and replacement 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.
K. 
Substantial improvements to existing manufactured homes shall:
1. 
Be elevated so that the lowest floor is at a minimum of the base flood elevation;
2. 
Be securely anchored to a permanent foundation system to resist flotation, collapse or lateral movement.
L. 
All preliminary subdivision proposals shall identify the special flood hazard area and the elevation of the base flood:
1. 
All subdivision plans will provide the elevation of proposed structure(s) and pad(s). If the site is filled above the base flood elevation, the lowest floor and pad elevations shall be certified by a registered professional engineer or surveyor and provided to the Floodplain Administrator;
2. 
All subdivision proposals shall be consistent with the need to minimize flood damage;
3. 
All subdivision proposals shall have public utilities and facilities such as sewer, gas, electrical and water systems located and constructed to minimize flood damage;
4. 
All subdivisions shall provide adequate drainage to reduce exposure to flood hazards.
(Ord. 1257 § 2, October 15, 2012)
Located within areas of special flood hazard established in Section 18.04.050(B) are areas designated as "floodway." The regulatory floodway is an extremely hazardous area due to the velocity of the floodwaters which carry debris, potential projectiles and erosion potential. The following provisions apply to areas designated as "floodway":
A. 
No encroachments, including fill, or other development, as defined by this chapter, shall be permitted within an adopted regulatory floodway, unless it is demonstrated by a registered professional engineer or architect that the encroachment shall not result in an increase in flood elevation during the occurrence of the base flood discharge.
B. 
If Section 18.04.110(A) is satisfied, all new construction and substantial improvements shall comply with all other applicable flood hazard reduction provisions.
(Ord. 1257 § 2, October 15, 2012)
For a proposed development on tidelands as defined in this chapter, a study and report by a qualified environmental biologist or other specialist in the field shall be required. The report shall classify and document the site in terms of its unique, intrinsic value as a wildlife habitat, and where there are differences in the value or sensitivity of portions of the site, shall rate them in order of lowest to highest wildlife resource value. Based on these classifications and ratings, the report shall contain specific recommendations on portions of the site that should not be disturbed in any manner, portions of the site that can sustain limited modification without major loss of resource value, and portions of the site best suited to development. Development permits for development on tidelands may be approved or conditionally approved only when it is found that:
A. 
Public benefits from development clearly exceed public detriment from the loss of the designated areas; that the project is limited to water-oriented uses, or consists only of minor fill for improving shoreline appearance or public access to the bay or other waterway, or if the property does not front on the bay or other waterway, does not adversely affect public access to the bay or other waterway;
B. 
Suitable upland location is not available for the proposed project;
C. 
The area to be developed is the minimum necessary to achieve the purpose of the project;
D. 
The nature, location and extent of the proposed development is such that it will not cause harmful effects to the bay area, such as the reduction or impairment of the volume surface area or circulation of water, water quality, fertility of marshes or fish or wildlife resources;
E. 
The proposed development will be constructed in accordance with sound safety standards which will afford reasonable protection to persons and property against the hazards of unstable geologic or soil conditions or of floodwaters, thus safeguarding public health, safety, welfare, and interests of all property owners;
F. 
The proposed development will not cause or increase the likelihood of flooding, polluting, eroding or silting of adjoining lands;
G. 
The proposed development will not destroy or accelerate the destruction of habitats essential to species of fish, shellfish, and other wildlife or plants of substantial public benefit;
H. 
The proposed development will not diminish the scenic beauty of the shoreline in a manner which will impede future construction of parks and recreation facilities;
I. 
The proposed development will not create a safety hazard in connection with potential settlement of fill or earthquakes, or landslides and similar instabilities;
J. 
The proposal does not violate any adopted City General Plan or specific plan.
(Ord. 1257 § 2, October 15, 2012)
The City Council may issue a variance under the provisions of this chapter for floodplain management purposes only. The characteristics must be unique to the property and not be shared by adjacent parcels. The unique characteristic must pertain to the land itself, not to the structure, its inhabitants, or the property owners. It is the duty of the City of Mill Valley to help protect its citizens from flooding. This need is so compelling, and the implications of the cost of insuring a structure built below flood level are so serious, that variances from the flood elevation or from other requirements in this chapter shall only be granted based on the strict application of the findings listed, below. The long term goal of preventing and reducing flood loss and damage can only be met if variances are strictly limited.
A. 
In passing upon requests for variances, the City Council shall consider all technical evaluations, all relevant factors, standards specified in other sections of this chapter, and the following, as may be applicable:
1. 
Danger that materials may be swept onto other lands to the injury of others;
2. 
Danger of life and property due to flooding or erosion damage;
3. 
Susceptibility of the proposed facility and its contents to flood damage and the effect of such damage on the existing individual owner and future owners of the property;
4. 
Importance of the services provided by the proposed facility to the community;
5. 
Necessity to the facility of a waterfront location, where applicable;
6. 
Availability of alternative locations for the proposed use which are not subject to flooding or erosion damage;
7. 
Compatibility of the proposed use with existing and anticipated development;
8. 
Relationship of the proposed use to the General Plan and floodplain management program for that area;
9. 
Safety of access to the property in time of flood for ordinary and emergency vehicles;
10. 
Expected heights, velocity, duration, rate of rise, and sediment transport of the flood waters expected at the site; and
11. 
Costs of providing governmental services during and after flood conditions, including maintenance and repair of public utilities and facilities such as sewer, gas, electrical, and water system, and streets and bridges.
B. 
A variance shall only be approved based on making all of the following findings:
1. 
That there is evidence in the public record to the satisfaction of the City Council of good and sufficient cause.
2. 
That failure to grant the variance would result in exceptional hardship as defined herein, to the applicant.
3. 
That the granting of a variance will not result in increased flood heights, additional threats to public safety, extraordinary public expense, create a nuisance or cause fraud and victimization of the public as defined herein or conflict with existing local laws or ordinances.
4. 
That the proposed new construction, substantial improvement and/or other proposed new development is necessary for the conduct of a functionally dependent use provided that the applicable provisions of subsection (A)(1)—(11) of this section are satisfied.
5. 
That the structure or other development is protected by methods that minimize flood damages during the base flood and does not result in additional threats to public safety and does not create a public nuisance.
6. 
That 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 of this chapter. (For example, in the case of variances to an elevation requirement, this means the City 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 City determines will both provide relief and preserve the integrity of this chapter).
C. 
The City Council may attach such conditions to the granting of a variance as it deems necessary to further the purposes of this chapter. The City Council shall require as a condition of approval to the granting of a variance that the property owner enter into a recorded agreement with the City, before a development permit is issued, providing that the property owner will defend, indemnify and hold harmless the City from any claims, actions, damages or liabilities arising in any manner from the granting of the variance.
D. 
Any applicant to whom a variance is granted shall be given written notice by the Floodplain Administrator that:
1. 
The issuance of a variance to construct a structure below the base flood level will result in increased premium rates for flood insurance, and that insurance premium rates are determined by statute according to actuarial risk and will not be modified by the granting of a variance.
2. 
Construction below the base flood level increases risks to life and property.
3. 
A copy of the notice shall be recorded by the Floodplain Administrator in the Office of the Marin County Recorder so that it appears in the chain of title of the affected parcel of land.
E. 
The Floodplain Administrator shall maintain a record of all variance actions, including justification for their issuance.
(Ord. 1257 § 2, October 15, 2012)
Appeals from any determination of the Floodplain Administrator pursuant to this chapter shall be made to the City Council. For purposes of this chapter, any appeal of a determination of the Floodplain Administrator shall be considered in the same manner as a variance and subject to the applicable provisions of Section 18.04.130.
(Ord. 1257 § 2, October 15, 2012)
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 such areas will be free from flooding or flood damages. This chapter shall not create liability on the part of the City of Mill Valley, any officer or employee thereof, the State of California, or the Federal Insurance Administration, Federal Emergency Management Agency, for any flood damages that result from reliance on this chapter or any administrative decision lawfully made hereunder.
(Ord. 1257 § 2, October 15, 2012)