Comprehensive Airport Land Use Plan for Sonoma County (CALUP)

Excerpt of the standards and policies from the CALUP adopted in January 2001 and amended in October 2001.

Chapter Eight

8.1  INTRODUCTION

This chapter presents the proposed Comprehensive Airport Land Use Plan for Sonoma County (CALUP). It includes a description of the referral area boundaries, noise compatibility standards, safety compatibility standards, airspace protection standards, and other land use policies for the six public use airports in the County. The various airport compatibility standards are to be applied comprehensively. Where any parcels of land are subject to more than one set of land use compatibility standards or policies, the most restrictive standard shall apply.

8.2  REFERRAL AREAS

8.2.1  BOUNDARIES

This section establishes geographic boundaries for referral of projects to the Sonoma County Airport Land Use Commission. In establishing these boundaries, a distinction can be made between the referral area of each of the six public-use airports in the County; defined as the area within which noise, airspace, or safety factors may affect land use compatibility - and the more limited area within which a close look at compatibility is essential. The latter is the primary referral area while the remaining portions of the airport influence area are treated as a secondary referral area.

The limits of the airport referral areas are set by the various compatibility zones described in this chapter. Except at the Sonoma County Airport, the airport referral area is bounded by the outer edge of the F.A.R. Part 77 conical surface. At Sonoma County Airport, the F.A.R. Part 77 approach surface for Runway 32 extends the boundary to the southeast. In addition, the 55 CNEL contour extends the boundary a short distance beyond the conical surface to the northwest off the end of Runway 14-32.

The secondary referral areas for each airport lie within the larger primary referral area. They include areas exposed to noise above 55 CNEL and beneath commonly used flight tracks and traffic patterns. These areas are discussed in greater detail below. In the secondary referral area, airport compatibility problems will seldom arise. The principal concern within the secondary referral area is the proposed construction of any structure to a height substantially in excess of that permitted under the land use zoning for that area.

Exhibits C1 through C6 show the referral area boundaries for each airport. As already noted, they encompass areas which are either beneath or near to the typical aircraft flight tracks or are projected to be affected by future noise levels of 55 CNEL or greater. Wherever possible, the boundaries follow roads or other easily identifiable geographic features. In some instances, parcel lines are used.

A brief discussion of the factors considered in drawing each set of referral area boundaries is included below. Descriptions of each airport's physical features, its use, and its environs are found in Chapters Two through Seven (not included in this excerpt).

8.2.1.a  Cloverdale Municipal Airport Referral Area

There is little existing land use incompatibility in the vicinity of the Cloverdale Municipal Airport. The Airport's environs consist primarily of agricultural and industrial areas plus the Russian River. Many future uses are projected to be similar. In addition, visitor-serving commercial and recreation areas are expected to be developed near the airport. One area of concern is the rising terrain beneath the traffic pattern northeast of the airport. Because this hillside is some 300 feet above the airport elevation, aircraft typically fly over at altitudes of only 500 to 700 feet above the ground. The agricultural and widely scattered rural residential uses which presently occupy this land are compatible with the airport, but any proposed development, especially of a residential nature, would have to be examined very critically.

The primary referral area for Cloverdale Municipal Airport (Exhibit C1) runs close to the airport on the west since there is no traffic pattern on that side, but extends some 6,000 feet to the east to encompass some of the high terrain in that area. The existing U.S. Highway 101 right-of-way provides a convenient western boundary. On the southwest side, Dutcher Creek Road, provides a partial boundary. On the other sides, the general lack of suitably located roads and other geographic features leads to reliance on parcel lines for definition of the referral area limits.

8.2.1.b  Healdsburg Municipal Airport Referral Area

Healdsburg Municipal Airport lies in a predominantly agricultural valley with rural residences scattered throughout. These airport-compatible uses are expected to continue. There are no major existing land use compatibility concerns, although new residential development has been occurring in the area.

On the southwesterly (traffic pattern) side of the field, portions of Dry Creek and Dry Creek Road form an appropriate primary referral area boundary (Exhibit C2) To the southeast, Chiquita Road provides a convenient limit. Few useful geographic features are available to the north, east, and south, however; the recommended boundary thus follows parcel lines as much as possible, falling back on an imaginary parcel line extension to provide the northeast boundary.

8.2.1.c  Petaluma Municipal Airport Referral Area

Petaluma Municipal Airport is at the northeast edge of the city. Most of the land north and east of the airport is agricultural or is dedicated parks and open space land. Residential development lies close to the airport on the southwest side.

Roads and parcel lines define a straightforward, nearly rectangular primary referral area (Exhibit C3). The boundaries are Mountain Parkway South on the southwest, Frates Road and a parcel boundary on the southeast, and a series of parcel lines 3,300 feet northeast of Adobe Road. On the northwest side, Sonoma Mountain Road, Old Adobe Road, and a series of parcel lines define the boundary.

8.2.1.d  Sonoma County Airport Referral Area

Although Sonoma County Airport is situated in predominantly agricultural countryside northwest of Santa Rosa, the nature of the airport's activity is such that its area of influence extends many miles from the airport property. The instrument landing approach to Runway 32 results in an approach zone which extends nearly 10 miles southeast of the runway. Additionally, the high volume of airport operations compared to the other five airports, plus the substantial number of business jet and large, piston-engine aircraft operations, results in a 55 CNEL contour extending from 1.5 to 2.5 miles beyond the runway ends.

The primary referral area is shown in Exhibit C4. Its greatest extension is to the southeast where it reaches Guerneville Road and then cuts back north to Piner Road in the southwest. On the southwest and west it follows a series of parcel lines. On the north, the line follows parcel lines within the Town of Windsor's sphere of influence. To the northeast and east, U.S. Highway 101, Fulton Road, and a series of parcel lines averaging 2,500 feet west of Fulton Road define the boundaries.

8.2.1.e  Sonoma Skypark Airport Referral Area

Sonoma Skypark lies in an agricultural area with many homes on rural acreages. The primary referral area, shown in Exhibit C5, follows Peru and Burndale Roads on the north, Ramal Road and its imaginary extension on the east, and the Southern Pacific Railroad, parcel lines, and Highway 12 on the south, and Shainsky Road and parcel lines generally aligned with the imaginary extension of that road on the west.

8.2.1.f  Sonoma Valley Airport Referral Area

Sonoma Valley Airport is a privately-owned facility used to a great extent by antique and aerobatic aircraft. Although numerous rural residences are located in the area, most of the airport vicinity consists of agricultural lands and flood plain. The area of greatest concern from an airport land use compatibility perspective is a residential area west of the airport along Meadowlark Lane.

The primary referral area boundary, shown in Exhibit C6, follows Bonneau Road and parcel lines on the north and then parcel lines, the North Western Railroad, Schell Slough, Steamboat Slough, and Sonoma Creek on the northeast, east, and southeast, respectively. Parcel lines provide most of the southern and western boundaries.

8.2.2  REFERRAL AREA POLICIES

According to State law, after the ALUC has found a local jurisdiction's general plan and specific plans to be consistent with the ALUC's Comprehensive Airport Land Use Plan, the local jurisdiction must submit proposed amendments to its general plan and specific plans and new zoning ordinances and building regulations to the ALUC for review. If the ALUC finds the proposal to be inconsistent with the CALUP, the local agency may, after a public hearing, overrule the ALUC by a two-thirds vote of it's governing body after making specific findings that the amendment is consistent with the purposes of the State law. (See Public Utilities Code, Chapter 4, Article 3.5, Section 21676(b).)

Public agencies owning any airport within the ALUC jurisdiction must also submit new or proposed revisions to the airport master plan to the ALUC for its review. If the ALUC finds that the proposed plan is inconsistent with the CALUP, the governing body of the airport may overrule the ALUC as noted above. (See Section 21676(c).)

Section 65302.3 of the Government Code requires general plans and applicable specific plans to be consistent with amended CALUPs. The ALUC must review these documents noting weather or not they are consistent with the CALUP, as amended. If they are not consistent, the local government must amend its general and specific plans within 180 days. The local jurisdiction may overrule the ALUC as discussed above.

Projects requiring FAA Notice of Construction or Alteration within the Secondary Referral Area shall be referred to the Airport Land Use Committee for review. Any proposed general and specific plan amendments or proposed zoning and building ordinances which would increase structural height within the Secondary Referral Area so greatly as to potentially cause penetrations of the Part 77 surfaces shall be referred to the ALUC for consistency determination.

8.3  NOISE COMPATIBILITY STANDARDS

Table 8A shows the proposed land use standards for noise compatibility for the public use airports in Sonoma County.

With the exception of hotels and motels, all residential uses are unacceptable with noise above 65 Community Noise Equivalent level (CNEL). Residences are conditionally acceptable between 55 and 65 CNEL, subject to an outdoor-to-indoor noise level reduction of at least 25 to 30 decibels. Avigation easements and fair disclosure agreements are also required of new dwellings between 55 and 65 CNEL.

Schools, libraries, hospitals, and nursing homes are unacceptable in areas exposed to noise above 60 CNEL. They are conditionally acceptable between 55 and 60 CNEL, subject to a noise level reduction of 25 decibels. Churches, auditoriums, and concert halls are unacceptable at noise levels above 65 CNEL. These are required to provide for noise level reductions of 25 to 30 decibels between 55 and 65 CNEL. Transportation, parking, and cemeteries are acceptable at noise levels up to 70 CNEL. Above 70 CNEL, they are conditionally compatible, subject to a noise level reduction of 25 decibels in office areas and portions of buildings where the public is received.

Hotels, motels, offices, and retail trade are unacceptable at noise levels above 70 CNEL. Noise level reductions of 25 to 30 CNEL are required for these uses between 60 and 70 decibels. Service commercial, wholesale trade, warehousing, and light industrial are conditionally acceptable at noise levels above 65 CNEL, subject to noise level reductions of 25 to 30 decibels. General manufacturing, utilities, extractive industry, and crop farming are acceptable at all noise levels.

Livestock breeding, zoos, and outdoor spectator sports are unacceptable at noise levels above 70 CNEL. Parks, playgrounds, golf courses, riding stables, and water recreation are conditionally compatible with noise above 70 CNEL. A noise level reduction of 25 decibels is required in office areas and portions of buildings where the public is received. As highly noise-sensitive outdoor uses, amphitheaters are unacceptable at noise levels above 55 CNEL.

8.3.1  NOISE POLICIES

1. Airport noise/land use compatibility shall be evaluated in terms of the Community Noise Equivalent Level (CNEL). The maximum CNEL considered normally acceptable for residential uses and noise-sensitive institutions in the vicinity of airports covered by this Plan is 55 CNEL.
2. Wherever uses are described as "unacceptable" in Table 8A, the Airport Land Use Commission shall disapprove development applications which would introduce those uses into areas impacted by noise above the designated level.
3. Uses designated as “conditionally acceptable” in Table 8A shall be permitted subject to the cited compatibility criteria.
4. Uses designated as “acceptable” in Table 8A shall be subject only to the referral area policies of Section 8.2.2.
5. The outdoor-to-indoor noise level reduction requirements in Table 8A are established with respect to aircraft noise. The intent is to ensure that the affected buildings are capable of attenuating aircraft noise events by the stated amount. In complying with the noise level reduction standards, buildings must be equipped with air conditioning or fresh air ventilation systems allowing windows and doors to remain closed. (Numerous empirical studies throughout California have indicated that standard construction following State Building and Energy Codes enables buildings to achieve an NLR of 25 decibels.)
6. The noise contours which shall be used for purposes of noise compatibility at each airport (the “regulatory noise contours”) are shown in Exhibits 8A through 8F. (Note: These exhibits are not in this excerpt.) The noise contours are forecasts for the year 2010.
7. The Airport Land Use Commission shall periodically update the regulatory noise contours as needed based on the availability of authoritative information. For purposes of this policy, authoritative information shall be considered to be updated noise contours developed as part of an F.A.R. Part 150 Noise Compatibility Study, an airport master plan, or an environmental impact report. Whenever the regulatory noise contours are updated, the Airport Land Use Commission shall bear in mind that the regulatory contours are intended to show a reasonable estimation of maximum noise exposure risk. Thus, the regulatory contours shall consider both current noise levels and projected future noise levels.

8.4  SAFETY COMPATIBILITY STANDARDS

8.4.1  SAFETY POLICIES

Table 8B describes the proposed safety compatibility standards for public use airports in Sonoma County. Six zones are proposed: the Runway Protection Zone, the Inner Safety Zone, the Inner Turning Zone, the Outer Safety Zone, the Sideline Safety Zone, and the Traffic Pattern Zone. New land uses proposed in any of these zones must comply with the standards of Table 8B. An explanation of these standards and the rationale for them is included in the following Subsections.

8.4.1.a  Intent of Safety Compatibility Standards

The intent of the land use safety compatibility standards is to minimize the risks associated with off-airport aircraft accidents or emergency landings. Risks to both people on the ground and people on the aircraft shall be considered. More stringent land use controls are applied in areas subject to greater potential risk.

8.4.1.b  Limiting the Density of People in Safety Areas

The most direct way to reduce risks to people on the ground is to restrict land uses so as to limit the number of people permitted to occupy an area.

Greater restrictions shall be placed on the number of people permitted in a building than within an open area because of the greater difficulty of evacuating a building in case of an aircraft accident. In addition, damage to the building caused by an aircraft accident can exacerbate the danger of the accident.

A methodology for determining whether a proposed structure complies with the population density requirements of any safety zone is presented in Appendix D.

8.4.1.c  Critical Land Uses

Land uses of particular concern from the perspective of safety compatibility are residential uses, uses attracting large concentrations of people, and uses in which the occupants have reduced effective mobility or are unable to respond to emergency situations. Schools, hospitals, nursing homes, and other uses in which the majority of occupants are children, the elderly, or handicapped are examples.

Other critical uses include those posing the risk of above-ground explosions or the release of toxic or corrosive materials. Critical uses also include public utilities or facilities which would cause significant public inconvenience or hazard in case their were disabled by an aircraft accident. Examples include public waterworks, wastewater treatment plants, power generating plants and substations, and public communication facilities.

8.4.1.d  Preservation of Useable Open Space

Useable open space is open and unobstructed land that could be used for forced landings by aircraft in emergencies. It must be relatively flat and free of significant obstructions, such as walls, large trees, buildings, and overhead wires. Streets and adjacent front yards, and parking lots shall be considered usable open space provided that they meet the minimum lot size and configuration requirements. The minimum size and configuration of useable open space shall not be less than 300 feet by 75 feet.

The reason for this requirement is that the risks to people on board aircraft and damage to property can best be minimized by providing as much open land area as possible within the airport vicinity. A large majority of aircraft accidents occurring away from an airport runway are controlled emergency landings in which the pilot has reasonable opportunity to select the landing site.

Clustering of development and providing contiguous yard and parking areas is encouraged as a means of maximizing open land and providing continuity of open land areas between developments.

In order to establish the open land areas available within a proposed development, building envelopes and the airport safety zones should be indicated on development plans.

8.4.1.e  Standards Applying in All Safety Zones

As noted in Table 8B, several other uses posing risks to aircraft in flight also shall be prohibited within all safety zones. These involve uses which would cause confusing or blinding lights and reflections to be directed to aircraft in flight, uses causing smoke, water vapor, or gatherings of birds, or those causing electrical interference. Rather than straight-forward land use restrictions, these may be considered performance standards. Only a few kinds of land uses have inherent attributes that would make them necessarily violate these standards. (Landfills and power generating plants are examples.) Many uses which might cause conflicts can be designed to avoid these problems. For example, businesses could design their lighting systems to avoid confusion with airfield lighting.

8.4.2  SAFETY ZONE BOUNDARIES

The safety zones for each airport are shown in Exhibits C1 through C6. Detailed drawings show the dimensions of the areas at each airport are provided in Appendix C (not included in this excerpt). The boundaries of the safety zones are defined based on the ultimate airfield layout as shown in the airport layout plan for each airport. The delineation of the boundaries of some safety zones, namely the ISZ, the SSZ, and, at Sonoma County Airport, the OSZ, pose some complications. These are explained in the following sections.

8.4.2.a  ISZ Boundaries

The boundaries of the Inner Safety Zones (ISZs) for the five small airports are defined based on the F.A.R. Part 77 criteria for the runway approach surface. For visual runways, the approach surface extends 5,000 feet off the end of the primary surface. The primary surface ends 200 feet off the runway end. The ISZ is defined as the part of the approach surface that lies at or below the elevation of the Part 77 horizontal surface. Depending on the elevation of the runway end, this will result in different lengths for the ISZ. Off runway ends with lower elevations, the ISZ will extend a greater distance before reaching the elevation of the horizontal surface. This is the reason for the variable lengths of the ISZs.

At Sonoma County Airport, the distances to the outer boundaries of the ISZs are the same as specified in the 1981 ALUPP. This distance is 5,100 feet off both ends of Runway 1-19 and the northwest end of Runway 14-32. It is 7,900 feet off the southeast end of Runway 14-32.

8.4.2.b  OSZ Boundaries at Sonoma County Airport

At Sonoma County Airport, the OSZ boundaries extend 10,000 feet off the northwest end of Runway 14-32 and off both ends of Runway 1-19. The outer boundary of the OSZ off the southeast end of Runway 14-32 extends 15,800 feet off the end of the primary surface or 7,900 feet from the end of the ISZ.

8.4.2.c  SSZ Boundaries

The SSZ boundaries are 1,000 feet off the runway centerlines and extend to the extension of the outside RPZ boundary line. Off most runway ends, the SSZs terminate at the ITZ.

8.5  AIRSPACE PROTECTION STANDARDS

The criteria defined in Part 77 of the Federal Aviation Regulations (F.A.R.) shall be the basis for airspace protection standards around all public use airports in Sonoma County. Exhibit 8G shows an example of an F.A.R. Part 77 airspace plan. (Note: The exhibit is not in this excerpt.) It includes an isometric drawing and a table summarizing the dimensional criteria. This is provided to assist readers in visualizing the rather complex F.A.R. Part 77 airspace.

F.A.R. Part 77 Airspace Plans for each public use airport in Sonoma County are shown in Exhibits 8H through 8P (Note: These exhibits are not in this excerpt.) The Part 77 airspace at Sonoma County Airport is shown in two exhibits. Exhibit 8L shows the Part 77 airspace within the primary referral area. Exhibit 8M shows the complete Part 77 airspace including the approach and transitional surfaces associated with the precision instrument approach to Runway 32.

8.5.1  AIRSPACE POLICIES

1.  No structure, tree, or other object shall be permitted to exceed the height limits established in accordance with Part 77, Subpart C, of the Federal Aviation Regulations (F.A.R.). This criterion applies unless, in the case of a proposed object or growing tree, one or more of the following apply:

1. The object would be substantially shielded by existing permanent structures or terrain in a manner such that it clearly would not affect the safety of air navigation;
2. The FAA has conducted an aeronautical study and either determined that the object would not result in a hazard to air navigation or made recommendations for the object's proper marking and lighting as an obstruction;
3. The object is otherwise exempted from the requirements of FAR Part 77; or, in the case of an existing object, it exceeds the prescribed height limits at the time the ordinance is adopted, in which case marking and lighting may still be required.

2.  No object shall be permitted to be erected which, because of height or other factors, would result in an increase in the minimum ceiling or visibility criteria for an existing or proposed instrument approach procedure.

3.  An object which would be located within a horizontal or conical zone as defined in F.A.R. Part 77, Subpart C, and would be 35 feet or less in height above the ground (i.e., is within the height limits prescribed for most Sonoma County land use zoning classifications) shall be considered conditionally acceptable even if it exceeds the prescribed height limit. Marking and lighting may be conditions for acceptability.

4.  The F.A.R. Part 77 Airspace Plans for each airport, as shown in Exhibits 8H through 8P, shall be used with the above airspace policies to determine whether the height of an object is acceptable.

5.  Beneath the F.A.R. Approach Surfaces up to a distance of 10,000 feet of the Part 27 Primary Surface to a publically owned airport, the owner of any property proposed for development shall grant an avigation easement to the airport owner. The avigation easement shall (a) provide the right of flight in the airspace above the property; (b) allow the generation of noise and other impacts associated with aircraft overflight; (c) restrict the height of structures, trees, and other objects not to exceed the elevations prescribed in the F.A.R. Part 77 Airspace Plan over the property; (d) permit access to the property with proper notice for the removal or aeronautical marking of objects exceeding the established height limit; (e) prohibit electrical interference, glare, and other potential hazards to flight from being created on the property. In the case of privately owned airports, mitigation measures shall be developed and implemented by local jurisdiction controlling land use which will mitigate potential conflicts noted below.

6.  Developers of a project which may exceed an F.A.R. Part 77 surface elevation must notify the Federal Aviation Administration (FAA) as required by F.A.R. Part 77, Subpart B and by the California Public Utilities Code Sections 21658 and 21659. (Notification to the FAA under F.A.R. Part 77 is required even for certain proposed construction that does not exceed the height limits established by Part 77. See Appendix D for the specific FAA notification requirements.)

1. Local jurisdictions and the ALUC shall inform affected developers of the FAA notification requirements.
2. The requirement for FAA notification shall not necessarily trigger review of an individual project by the ALUC unless review is required by another provision of this Comprehensive Airport Land Use Plan.
3. Any project coming before the ALUC because of height-limit issues shall include a copy of the F.A.R. Part 77 notification to the FAA.

8.6  OTHER LAND USE POLICIES

8.6.1  POLICIES APPLY TO NEW DEVELOPMENT

The policies of this Comprehensive Airport Land Use Plan shall apply only to new development. Under State law, the ALUC has no jurisdiction over existing development.

8.6.2  EXISTING LAND USES NOT CONFORMING TO STANDARDS

Existing land uses which do not conform to the standards of this Plan shall be exempt from those standards except as noted in this subsection. Modification of those uses shall be permissible, provided that the modification does not increase the magnitude of the nonconformity. Examples of prohibited enlargements would be increases in the degree of nonconformity with population density, dwelling unit density, or minimum useable open space standards. (The addition of a room to a nonconforming home would be a permissible enlargement as long as the minimum useable open space standards were not violated and no new dwelling units were being added.)

Where an existing nonconforming building or use has been partially or fully destroyed, it may be rebuilt to a density and intensity not exceeding that of the original construction.

The reinstitution of a legal non-conforming use shall be exempt where the owner has made a good-faith effort to continue the previous use by obtaining the necessary land use permits from the local jurisdiction to re-establish or reconstruct the use within twelve months of the date of destruction of the use which occurred through no fault of the owner. In addition, modification or reconstruction of nonconforming uses shall be subject to the Referral Area Policies of Subsection 8.2.2 and the Airspace Protection Policies of Section 8.5.

8.6.3  EXISTING LOTS NOT CONFORMING TO STANDARDS

Residential lots existing as of the date of adoption of this Plan which do not conform to the minimum lot size requirements of this Plan shall be considered legally nonconforming. They may be used and built upon, provided that all other applicable standards of this Plan are complied with.

The use of a non-conforming parcel would not be totally prohibited where the strict application of the commission's updated policies would otherwise render the parcel unusable.

8.6.4  FINDINGS AS TO SIMILAR USES

Cases may arise where the Airport Land Use Commission must review a proposal for development of a land use which is not explicitly provided for by the land use standards of Table 8A (noise compatibility) or Table 8B (safety compatibility). In such cases, the ALUC shall apply conventional rules of reason in determining whether or not the subject land use is substantially similar to any land use which is subject to regulation. In making these determinations, the ALUC shall review the background analysis used to develop this Comprehensive Airport Land Use Plan document, including technical appendices and "Discussion Papers". The ALUC shall also review the latest edition of the Airport Land Use Planning Handbook prepared under the direction of the State Aeronautics Program.

With respect to noise compatibility, the ALUC shall refer to the "Suggested Land Use Compatibility Guidelines" of the Federal Interagency Committee on Urban Noise, presented in Table A7 of the Discussion Paper published in October 1997, for assistance in making findings as to similar uses.

8.6.5  FINDINGS FOR LAND USES WHICH ARE TO BE DISCOURAGED

Within the TPZ, a variety of land uses are to be discouraged from being developed. (See Table 8B.) When development of these uses is proposed, the ALUC shall require the applicant to show that alternative locations have been considered and are not feasible. The applicant shall then be directed to consider a development plan that will minimize as much as possible the exposure to hazard. This might involve reducing structure heights, reducing lot coverage, reducing the overall scale of the project, or considering satellite locations for some of the proposed functions of the facility.

Land uses described as "uses to be discouraged" which were lawfully established before the adoption of this Comprehensive Airport Land Use Plan shall be permitted to be modified. Modifications which would enlarge the land use shall be discouraged in accordance with the requirements of this section.

Factors to be considered are:

• Alternative locations are completely unavailable.
• Alternative locations are not feasible because they would require a material change in the proposed development which would compromise its intended purpose or scope of activity.
• Alternative locations within the service area of the proposed use are unavailable.
• Alternative locations are substantially more costly and are beyond the means of the project sponsor.

8.6.6   PROJECTS PREVIOUSLY SUBMITTED UNDER THE CURRENT POLICIES:

All projects which received a determination of conformance under the previous policy plan would be exempted from compliance by policies contained in this plan, provided however, that any modifications of those projects from what was presented to the Comprehensive Airport Land Use Commission would be required to be resubmitted to the commission for further review to determine whether or not the proposed modifications would be in substantial conformance with the project the commission approved by the commission under its previous policy plan.

All projects which have been determined to be consistent with the commission's previous policy plan shall be exempt, except as provided below:

1. The project has not expired under the local jurisdiction's regulations or state law;

2. The project has not been modified from what was determined by the commission to be consistent with its previous policy plan so as to constitute a new project.

(For example, where a realignment of the project streets is proposed which would not result in any increase in densities within the extended centerline protection zones above the densities set forth in the previous policy, that modification would be consistent. However, where a project is modified to increase the density or intensity of use within the extended centerline safety zones, then that project would constitute a new project which would be subject to compliance with the policies contained in this plan.)

Any project which does not meet either of the foregoing exceptions would, at the discretion of the commission, be subject to meeting the policies contained in this plan.

8.7  IMPLEMENTATION AND ADMINISTRATION

8.7.1  ADOPTION OF PLAN

The Sonoma County Airport Land Use Commission (ALUC) adopted the updated Comprehensive Airport Land Use Plan (CALUP) in January 2001. Public hearings were held prior to adoption of the Plan.

The approved Comprehensive Airport Land Use Plan will be the ALUC's official land use policy document within the airport influence areas for all six public use airports in the County. ALUC decisions and recommendations on development actions proposed within the airport influence areas shall be based on the policies of the CALUP.

8.7.2  UPDATE AND AMENDMENT OF PLAN

The Sonoma County ALUC and its staff should take care to keep the CALUP up-to-date. It should review the plan as often as necessary, although according to state law it may not be amended more than once per year.

It will be especially important to review the plan whenever the airport master plans or airport layout plans are amended. Changes in runway alignments or runway lengths in particular could require amendments to the CALUP. At the same time, it is important for the ALUC to ensure that the CALUP is considered during any future master plan update studies.

The ALUC also should review the CALUP when new guidance documents are prepared by the California Department of Transportation. It is important for the CLUP to consider the latest relevant information and research on noise, safety, and height compatibility issues, particularly when that information has been evaluated and weighed through an authoritative consultation process.

The ALUC and staff should also review the CALUP whenever experience indicates that unanticipated difficulties are being encountered that might be solved through appropriate amendments to the plan.

8.7.3  ALUC REVIEW OF LOCAL GENERAL AND SPECIFIC PLANS

The State Aeronautics Law (Public Utilities Code Chapter 4, Article 3.5) requires local general plans and specific plans to be consistent with the adopted Comprehensive Airport Land Use Plans of County Airport Land Use Commissions. The ALUC shall review the local general plans and specific plans of the affected jurisdictions to determine consistency with the ALUC's policies within 180 days of adoption of the Comprehensive Airport Land Use Plan.

Where inconsistencies exist, the ALUC shall notify the affected jurisdiction. The local agency may overrule the ALUC after holding a public hearing and after making specific findings that the existing plans are compatible with the purposes of the aeronautics law. A two-thirds majority vote of the governing body is required. (See Section 21676(a)).

Until such time as the ALUC finds that the local general plan or specific plan is consistent with the CALUP; or the local agency has overruled the ALUC's determination, all actions, regulations, and permits shall be referred to the ALUC for a consistency determination (Section 21676.5 (a)).

If the ALUC finds that the local agencies have not revised their general or specific plans or overruled the ALUC with the required two-thirds vote, State law enables the ALUC to require that the local agencies submit all development actions, regulations, and permits to the ALUC for review. If the ALUC finds that the proposed action is not consistent with the CALUP, the local agency shall be so notified and shall hold a public hearing to reconsider its plan. The local agency may overrule the ALUC with a two-thirds vote of its governing body if it makes specific findings that the proposed action is consistent with the purposes of Section 21670 of the Aeronautics Law. (See Section 21676.5(b)).

8.7.4  SCOPE OF ALUC PROJECT REVIEW RESPONSIBILITIES

Where the local agencies have amended their general and specific plans to be consistent with the Comprehensive Airport Land Use Plan, or where they have overruled the ALUC's finding of inconsistency, then the following types of actions proposed within the primary airport referral areas shall be referred to the ALUC for determination of consistency with the CALUP prior to their approval by the local jurisdiction:

• The adoption or approval of any amendment to a general or specific plan affecting the Commission's geographic area of concern as indicated in paragraph 1.1 (Section 21676 (b)).
• The adoption or approval of a zoning ordinance or building regulation which (1) affects the Commission's geographic area of concern as indicated in paragraph 1.1 and (2) involves the types of airport impact concerns listed in paragraph 1.2 (Section 21676 (b)).
• Adoption or modification of the master plan for an existing public-use airport (Section 21676 (c)).
• Any proposal for a new airport or heliport whether for public or private use (Section 21661.5).

8.7.4.a  Other Project Review

Other types of actions which may involve a question of compatibility with airport activities should also be referred to the ALUC through voluntary agreements with the local government agencies (Section 21676.5 (b)). The ALUC shall review the following types of actions:

1. Any proposed expansion of a city's or an urban service district's sphere of influence within an airport's planning area.
2. Any proposed residential rezoning or planned unit development consisting of five or more dwelling units within an airport's planning area.
3. Any request for variance from a local agency's height limitation ordinance within an airport's planning area.
4. Any proposal for construction or alteration of a structure (including antennas) taller than 150 feet above the ground anywhere within the County.
5. Any major capital improvements (e.g., water, sewer, or roads) that would promote urban development.
6. Proposed land acquisition by a government entity (especially, acquisition of a school site).
7. Any other proposed land use action, as determined by the local planning agency, involving a question of compatibility with airport activities.
8. Any proposal requiring notification to the Federal Aviation Administration under Federal Aviation Regulations Part 77, Subchapter B, regardless of the location in the County. There is no requirement for local agencies to enter into these voluntary agreements.

8.7.4.b  Review Process

Proposed development actions subject to ALUC review must be submitted to the ALUC for review prior to approval by the local government entity. All projects should be referred to the ALUC at the earliest reasonable point in time so that the ALUC's review can be duly considered by the local jurisdiction prior to formalizing its actions.

When reviewing a land use proposal, the ALUC has a choice of either of two actions: (1) find the project consistent with the CALUP; or (2) find the project inconsistent with the CALUP. The ALUC cannot, however, find a project consistent with the Plan subject to the inclusion of certain conditions in the project.

Once a project has been found consistent with the CALUP, it need not be referred for review at subsequent stages of the planning process (e.g., for a general plan amendment and again for a zoning change) unless: (1) major changes to the project are made during subsequent review and consideration by the local jurisdiction; or (2) the local jurisdiction agrees that further review is warranted.

The ALUC must respond to a local agency's request for a consistency determination on a project within 60 days of referral. If the ALUC fails to make the determination within that period, the proposed action shall be deemed consistent with the Comprehensive Airport Land Use Plan.

8.7.4.c  Review of Airport and Heliport Master Plans

When reviewing airport master plans for existing airports, the ALUC has three action choices:

Find the airport master plan consistent with the Comprehensive Airport Land Use Plan.

1. Disapprove the airport master plan on the basis that it is inconsistent with the ALUC's Plan.
2. Modify the Comprehensive Airport Land Use Plan (after duly noticed public hearing) to reflect the assumptions and proposals in the airport master plan.

When reviewing proposals for new airports or heliports, the ALUC's choices of action are:

1. Approve the proposal as being consistent with the specific review policies listed in Section 2.3 below.
2. Approve the proposal and adopt a Compatibility Plan for that facility. Adoption of such a plan is required if the airport or heliport will be a public-use facility.
3. Disapprove the proposal on the basis that the noise and safety impacts it would have on surrounding land uses are not adequately mitigated.

When reviewing master plans for existing airports, the ALUC shall determine whether the activity forecasts or proposed facility development identified in the proposed master plan differs substantially from the forecasts and developed assumed for that airport in the Comprehensive Airport Land Use Plan. Attention should specifically focus on:

1. Activity forecasts that are: (1) significantly higher than those in the CALUP; or which (2) include a significantly higher proportion of larger or noisier aircraft.
2. Proposals to: (1) construct a new runway or helicopter takeoff and landing area; (2) change the length, width, or landing threshold location of an existing runway; or (3) establish an instrument approach procedure.

The ALUC shall determine whether the proposed airport master plan is consistent with the CALUP. The ALUC shall base their determination of consistency on findings that the forecasts and development of the airport would not result in greater noise, overflight, and safety impacts or height restrictions on surrounding land uses than are presently assumed in the Comprehensive Airport Land Use Plan.

8.7.5  OTHER ADMINISTRATIVE RESPONSIBILITIES

8.7.5.a  Coordination with Local Governments

The ALUC should ensure that proper coordination is established between its staff and local governments to ensure the efficient administration of the development review process. The local jurisdictions with land use regulatory authority within the airport influence areas must understand the boundaries of the airport influence areas and have clear maps available to them. The city or County planning departments are usually the first point of contact with a developer. It is important that they be able to relay information as to whether a project is subject to review by the ALUC.

It is also important that the local government agencies be kept informed as to the appropriate staff contact for the ALUC when information about the ALUC's development review process is desired.

It may be appropriate for the ALUC and its staff to consider preparing a simple handout or brochure which explains the ALUC's development review process. It might include information about the process of reviewing a development proposal, scheduling a proposal for a hearing before the ALUC, and the consequences of action by the ALUC.

8.7.5.b  County Geographic Information System

Sonoma County has established a geographic information system (GIS) for the entire county. The system is managed by the Information Systems Department. The GIS is essentially an intelligent computerized mapping system. Geographic data can be analyzed and mapped in many different ways. Among the data in the system are streets, streams and watercourses, railroads, and property lines.

Administration of the CLUP would be enhanced if the boundaries of the regulatory areas were added to the GIS. The system could be used in various helpful ways. For example, if the boundaries of a development project were encoded into the system, the GIS could be queried to determine whether the parcel was inside a CLUP regulatory area. If it was, a map could be produced and an estimate of the affected land area could be produced.

For the GIS system to be effective, it is necessary to encode the airport layout plans into the system as well as the various regulatory areas. This would ensure the proper definition of runway coordinates, bearings, and elevations, the foundations for defining the regulatory area boundaries.

A GIS can be especially helpful in the administration of height standards. If the F.A.R. Part 77 Airspace Plans were entered into the system in a three-dimensional format, a GIS with three-dimensional topographic data would be capable of producing a structural penetration analysis quickly and easily. As long as the structure location, height, and surface topography were known, the system could determine whether a penetration of a Part 77 surface would occur. It could also produce three-dimensional maps of the affected area. The ALUC staff should coordinate with County staff to determine if the County GIS can be adapted for this purpose. If so, the ALUC should consider developing three-dimensional Part 77 Airspace Plans.

8.7.5.c  Criteria for ALUC Review of General Plan Amendments

Sonoma County and the airport area cities may consider amendments to their general plans from time to time. The major consideration of the ALUC as it reviews future general plan amendments is to ensure that the standards of the CALUP are complied with.

In some noise and safety zones, the policies of this Plan prohibit or limit the density of residential development. From the standpoint of airport compatibility, any future amendments to local general plans or new specific plans involving density transfers generally would be acceptable. ("Density transfer" means allowing credit for unused residential development potential within the particular noise/safety zone to be transferred to a part of the property outside the noise/safety zone.) This shall not be interpreted as acceptance of any waivers from the land use compatibility policies of this plan. Density transfers shall be acceptable only if all land use policies within the airport influence area are complied with.

REFERENCES

Coffman Associates, 1997. Comprehensive Airport Land Use Plan Update, Sonoma County -- Discussion Paper: Alternative Approaches for Setting CLUP Policies. Prepared for Sonoma County Airport Land Use Commission, October 1997.

Hodges & Shutt 1981. Recommended Airport Land Use Policy Plan for the Sonoma County Airport Land Use Commission. Prepared for Sonoma County, June 1981.

Hodges & Shutt 1991. Airport Land Use Compatibility Plan, Napa County Airport Land Use Commission. Adopted April 22, 1991.

Hodges & Shutt 1993. Airport Land Use Planning Handbook. Prepared for California Department of Transportation Division of Aeronautics, by Hodges & Shutt in association with Flight Safety Institute, Chris Hunter & Associates, and University of California, Berkeley, Institute of Transportation Studies. December 1993.

Metropolitan Transportation Commission 1983. Airport Land Use Planning Handbook: A Reference and Guide for Local Agencies. Prepared for California Department of Transportation, Division of Aeronautics by the Metropolitan Transportation Commission and the Association of Bay Area Governments. July 1983.