Aircraft Noise: A Toolkit for Managing Community Expectations (2009)

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The reduction of adverse aircraft noise impacts on noise-sensitive land uses is dependent not only on the abatement of aircraft noise at the source or through operational techniques, but also through the management of the use of land that remains exposed to high noise levels after abate- ment measures are implemented. There would be little logic in modifying flight activity to focus or disperse noise over compatibly used land if that land were to be built up in noise-sensitive uses by future development action. This chapter will discuss a series of land use management oppor- tunities available to airports and communities to seek a balance between airside and landside responsibilities for maintaining compatibility between the airport and its neighbors. Since the retirement of louder, older aircraft from the operating mix began in the mid-1980s, aircraft manufacturers and operators have contributed substantially to the reduction of the size of the areas deemed incompatible around airports. Their conversion to new aircraft types and/or quieter engines has resulted in the removal of millions of persons from within the 65 DNL foot- prints around the nation’s airports. As the contours have shrunk, lands that had previously been deemed incompatible for the development of noise-sensitive uses no longer fell within the 65 DNL contour and hence became eligible for compatible development. Throughout the history of the conflict between aircraft noise and noise-sensitive uses, land developers have applied pressure to reduce the contour and open the land to development. Communities with land use jurisdiction face conflicting pressures from developers who wish to bring vacant lands to their highest and best use, and from airport advocates who wish to main- tain unimpeded abilities to use the airport. Until the mid-1990s actions were possible on the avi- ation side of the conflict that would allow tweaking of flight paths, runway use, and operating procedures to make increasingly smaller adjustments to noise contours. However, as the overall contour size shrank from reduced noise emissions at the aircraft source, the costs to make mean- ingful flight management changes to enhance compatibility began to exceed the benefits. With the passage of Lott Amendment to the Vision 100 Century of Aviation Reauthorization Act of 2003 (140), Congress formally banned the use of federal funding to mitigate noise beyond the 65 DNL contour. Although that provision expired on December 31, 2007, FAA policies are now in place that discourage the expenditure of funds to not only mitigate noise-sensitive land uses beyond the 65 DNL contour, but also to modify flight paths that effect noise conditions there. The position now taken by the FAA, as well as nearly all other aviation groups, is a call for bal- ance between the airside and the landside management efforts to control the incompatibilities between aircraft noise and noise-sensitive land uses. User advocates have taken a stand for more control at the local level to prohibit the introduction of potential new incompatible land uses into areas where aircraft noise remains above 65 DNL, and where possible, within an envelope around the contour to assure that future growth at the airport will not reintroduce noise impacts into areas that are allowed to newly develop adjacent to the current contour of significant exposure. In March 133 C H A P T E R 9 Land Use Management Techniques for Noise Abatement

1998, the FAA published its final policy on the approval of Part 150 measures for noise mitigation projects, and in it, prohibited the use of federal funding to mitigate dwellings constructed within a published 65 DNL contour after October 1998 (177) Several state governments also have provided guidance to communities regarding the plan- ning for compatibility between airports and their surrounding uses. Two substantial examples of this guidance include: • State of Washington – Airports and Compatible Land Use, Volume 1 (178) • State of California – California Land Use Planning Handbook (179) and at http:// www.dot.ca.gov/hq/planning/aeronaut/documents/ALUPHComplete-7-02rev.pdf The following provides an overview of the opportunities available to communities and air- ports to seek and maintain compatible land uses within the areas affected by noise levels that are determined to be locally significant. For more information, the reader is directed to the ACRP Project 03-03, Enhancing Airport Land Use Compatibility website at www.trb.org. Land Management Actions an Airport May Implement The airport may undertake several land use management actions on its own initiative. Other actions rely upon the powers of other local agencies to control the presence or introduction of incompatible uses within the areas exposed to significant levels of aircraft noise. Each airport-only action involves the acquisition of land or some portion of the various land rights held by a prop- erty owner. Purchase of Non-Compatible Land Purpose: The purpose of this strategy is to acquire property and relocate any occupants who reside within contours of significant noise. Once the land is owned by the airport, it can be re-allocated to a compatible land use for that noise level. Although expensive, it is the most effec- tive tool for the airport to eliminate incompatible uses and control future development risks. Limitations: Federal funding is available for acquisition of properties identified as part of an approved Noise Compatibility Program or as mitigation for an Environmental Impact document. It can be a costly and time consuming process to undertake for airports with limited funding. There may be objection by local communities for removal of property from tax rolls or from parties to a use agreement who disagree with the proposal. Implemented by: The airport, usually with funding assistance by the FAA. Public reaction: The public may view this strategy as an excuse for the airport to “land grab.” Local jurisdictions typically are concerned about developable property being removed from the local tax rolls. Example of Technique for Public Information: • Land Acquisition for Public Airports (180) • Voluntary Land Acquisition & Relocation Program (Harrisburg, PA) (181) 9-5 9-4 9-3 9-2 9-1 134 Aircraft Noise: A Toolkit for Managing Community Expectations

• Voluntary Acquisition/Relocation Assistance Program (Providence, RI) (182) • FAA Order 5100.37B Land Acquisition and Relocation Assistance for Airport Projects (183) Acquisition of Noise and Overflight Easements Purpose: A noise or overflight (avigation) easement may be purchased by the airport on prop- erties that are noise-impacted, but will not be mitigated through other means. It grants permis- sion to the airport for aircraft to fly over the property while using the airport, and in most cases to make noise of a given level or less. A noise easement transfers with any change of property ownership. Easement purchase programs may be designed for homeowners who are either not eligible for other mitigation programs or choose to not participate. Purchase of easements allows current land use to remain in effect and maintains local tax rolls. Limitations: The value of easements is often nominal unless individual appraisals are under- taken, which can be costly. The purchase of an aviation easement without a sound insulation program does not ‘mitigate’ the property; it only ‘mitigates’ the existing property owner for exist- ing impacts and often does not change public attitudes to the airport, particularly in regard to growth or airport expansion issues. Theoretically, the value of the easement contributes to a dis- counted future value of the property on its sale. Implemented by: Airports, with or without funding assistance by the FAA. Public reaction: The public generally perceives the purchase of an aviation easement as a jus- tifiable reward for accepting the nuisance of continuous aircraft noise effects. Example of technique for public information: • Sample Avigation Easement (Raleigh, NC) (184) • Deed of Easement and Declaration of Protective Covenants (Columbus, OH) (185) • Deed of Easement (Sound Insulation Program) (Cincinnati, OH) (186) • Noise and Avigation Easement and Covenant Not to Sue (Scottsdale, AZ) (187) Waiver of Claim Purpose: A waiver of claim is similar to an easement in that the property owner forfeits the right to any claims that may be made as the result of nuisance imposed by aircraft noise. Also known as “non-suit covenants” or “hold harmless agreements”, they are legal instruments usually incor- porated into an avigation or noise easement. They document that the owner has agreed not to sue the airport over noise issues, in exchange for monetary compensation or some other benefit. They are normally carried on the deed of property as a restrictive covenant accompanying an avigation easement. Limitations: As with easements, the value of a waiver of claim is difficult to determine and may be settled as a percentage of the assessed or appraised value of the property. Further, a waiver of claim does not ‘mitigate’ the property, but rather ‘mitigates’ the property owner through compen- sation or a discounted sale price on the property when transferred. It generally mitigates for exist- ing or forecast impacts and often does not change public attitudes to the airport, particularly in regard to growth or airport expansion issues. 9-11 9-10 9-9 9-8 9-7 9-6 Land Use Management Techniques for Noise Abatement 135

Implemented by: Airports, with or without funding assistance by the FAA, when established through a Noise Compatibility Program or environmental mitigation program. Public reaction: The action is generally transparent to the general public. Development Rights Transactions Purpose: Where acquisition is not an option and a vacant property is located within an area of significant noise exposure, the purchase of the rights to develop that property in incompat- ible uses may be a viable approach to land use management. Development rights may be acquired or transferred. Purchase of development rights (PDR) transfers all rights to develop a property in incompatible uses from the property owner to the acquiring party—in these cases the airport. The value of the transfer is appraised comparably to that of an easement. The transfer of development rights (TDR) allows the owner of the sending property to develop property in another location that would not normally be approved for the proposed develop- ment. For example, potential for a high density development proposed in an area of signifi- cant noise exposure may be transferred to an area that local plans indicate should be developed in a lower density. Limitations: There must be state enabling legislation to permit such transactions. Implemented by: Airports, with support of local planning and zoning authorities. Public reaction: Typically, the property owners adjacent to the parcel where the rights are being transferred ‘from’ are in favor; the property owners adjacent to the parcel where the rights are being transferred ‘to’ are generally opposed. This is because such a transfer of devel- opment rights typically means the rights being transferred will permit a higher density of development. Purchase Assurance/Sales Assistance Purpose: Purchase assurance and sales assistance programs are intended to provide homeown- ers in noise-impacted areas an assurance they will be able to sell their property for fair market value. Under purchase assurance the airport proprietor agrees to acquire the property as a pur- chaser of last resort if the homeowner was unable to sell on the open market. The airport may place limitations on the guarantee amount relative to the appraised value of the property (e.g., 90 percent of appraised market value) to assure that the owner has made an adequate effort to sell the property prior to applying for purchase assurance. The airport then sells the home and retains an aviation easement after making sound insulation or other property improvements. Under sales assistance programs, the airport may support the homeowner in the independent sale of the property in exchange for easement or other deed considerations by paying closing costs, or subsidizing a portion of the difference between the appraised value of the property and the final sales price. Limitations: Purchase assurance and sales assistance programs can be fairly complex and time- consuming to administer. They also open up the risk that the airport will become a property manager or landlord if market conditions make it difficult to sell homes. The program should be carefully staged to prevent more applicants than can be dealt with effectively at any one time. Otherwise, an adverse reaction in the larger real estate market could be caused. Implemented by: Airport with potential funding assistance from FAA. Public reaction: Generally purchase assurance and sales assistance programs are well-received by the public. This program allows the existing property owner an opportunity to leave the area 136 Aircraft Noise: A Toolkit for Managing Community Expectations

impacted by 65+ DNL noise levels and fully discloses the existing (and potential future) noise environment to a new, willing, and informed buyer. Sound Insulation of Noise-Sensitive Noncompatible Structures Purpose: This technique provides for the addition of insulation, noise attenuation baffles, solid core doors, double paned windows, and possibly air conditioning units to noncompat- ible buildings located within the 65 DNL and higher noise contour at airports with an approved Part 150 Noise Compatibility Program. Participation in a sound insulation pro- gram generally requires that the homeowner provide an avigation easement and non-suit covenant attached to the deed of property, as well as an agreement to noise level disclosure upon sale. Limitations: Sound Insulation programs can be time consuming and complex. They involve construction and a great deal of homeowner outreach. Implemented by: Airports, with FAA funding support. Public reaction: In general, the public response to implementing a sound insulation program is favorable. A community welcomes sound insulation programs because it brings with it an assumed improvement in the quality of life to areas impacted by a 65+ DNL noise contour. One negative comment typically made about such programs is that sound insulation does not miti- gate the aircraft noise effects for outdoor activities. Example of Technique for Public Information: • Homeowner Handbook – Bradley International Airport Residential Sound Insulation Program (Hartford, CT) (188) • Homeowner Handbook – Philadelphia International Airport Residential Sound Insulation Program (189) • Residential Sound Insulation Program Brochure (Lambert-St. Louis International Airport) (190) • San Antonio International Airport Residential Acoustical Treatment Program – Homeowner Brochure (191) Land Use Actions Requiring Implementation by Others There are actions available for land use management that the airport cannot enact, but may encourage through implementation by local planning or regulatory agencies. Each involves the control and development of future uses of property. Comprehensive Community Planning Purpose: The comprehensive planning process provides guidelines to the development of infrastructure and land use patterns within communities. When the effects of aircraft noise on community compatibility are used to guide the planning process, development that avoids the introduction of noise-sensitive uses into areas of significant noise exposure may be recom- mended. For example, the designation of undeveloped off-airport areas within the 65 DNL (or other) contour for industrial, commercial or open space uses will contribute to the prevention of future impacts. In contrast, the planning of water or sewer service to residential standards 9-15 9-14 9-13 9-12 Land Use Management Techniques for Noise Abatement 137

within the same area will make the ultimate development of incompatible uses in the air much more likely and will lead to future conflicts with the airport. Limitations: Requires the willingness of the local planning authority to develop comprehen- sive plans that place a high priority on compatibility and on elected authority to adopt them as policy decisions. Implemented by: Local jurisdictions based on airport recommendations. Public reaction: Public acceptance of the recommendations of the comprehensive planning process is typically dependent upon the community’s general acceptance of land use planning, policies, and zoning, as well as political interests and influences of those effected. Compatible Land Use Zoning Purpose: The formal adoption of development regulations that discourage or prohibit the placement of incompatible uses, as outlined in 14 CFR Part 150, Appendix A, Table 1, in areas within contours of significant noise exposure adjacent to an airport. Comparable state or local criteria may be similarly applied. Limitations: Requires the local zoning authority to implement. Implemented by: Local jurisdictions based on airport recommendations. Public reaction: Public acceptance of compatible land use zoning is typically dependent upon the community’s acceptance of comprehensive land use planning, policies, and zoning (in gen- eral) and political interests and influences. Noise Impact Overlay Zoning Purpose: The purpose of a Noise Impact Overlay Zone is to alert existing and future property owners of the possible noise impacts from a nearby airport. These zones also prevent or discour- age noncompatible development of property within the zone from occurring without the proper notice and documentation. Most overlay zones also address issues of structural height and seek to eliminate obstructions to aviation, require noise level disclosure on all properties, and may require avigation easements for new development approvals within their boundaries. Limitations: Requires the local jurisdiction to adopt and implement as part of its Comprehen- sive Plan or zoning ordinance. Often is subject to variance requests from developers. Implemented by: Local jurisdictions. Public reaction: General public acceptance of noise impact overlay zoning is typically depen- dent upon the community’s acceptance of comprehensive land use planning, policies, and zoning (in general) and political interests and influences Example of Technique for Public Information: • Airport Environs Overlay (192) • Airport Land Use Management District (ALUMD) (193) • Environmental Impact Districts Section 4-1400 AI-Airport Impact Overlay District (194) • Aircraft Noise Overlay District (195) • Noise Overlay District (Plainfield, IN) (196) 9-20 9-19 9-18 9-17 9-16 138 Aircraft Noise: A Toolkit for Managing Community Expectations

Subdivision Code Modifications Purpose: The purpose of a subdivision code is to establish consistent design criteria for the development of infrastructure and lot sizes to allow for the development of complementary uses within a subdivided area. To manage the compatibility between aircraft noise and noise-sensitive uses, the code may seek the limitation of the number of lots within higher noise levels, restrict the density of development on those lots, or direct that lots exposed to the highest noise levels be dedicated to compatible uses such as open space or nonresidential development. Subdivision plats are frequently used as the mechanism for attaching avigation easements and waivers of claim to the deed, as well as disclosure requirements on sale and transfer of property within any subdivided property as a condition of its approval. Samples of these tools are provided under other sections of this chapter. Limitations: Requires the local jurisdiction to adopt and implement as part of their regulatory documents, and requires local planning agencies having review authority to assure the attach- ment of any necessary covenants that apply within various noise areas. It is incumbent on the airport to assure that noise exposure contours are kept current with the planning agency to assure that their reviews are up to date. Implemented by: Local jurisdictions and planning agencies. Public reaction: Public acceptance of subdivision regulations is typically transparent. These provisions are normally in place prior to the transfer of property and come with covenants already in place. The development community may see all such subdivisions as detrimental to their ability to maximize the return on investment in the development of property. Dedication of Noise and Overflight Easements Purpose: A noise or overflight (avigation) easement may be acquired in one of several ways other than direct purchase. It may be attached and dedicated as a requirement for approval of a development plat or subdivision; it may be required to be dedicated as a condition of a zoning change; or required as a condition of another benefits program. In each case, it grants permis- sion for aircraft to fly over the property, and in most cases to make noise of a given level. It often includes a waiver of claim and requirement for noise level disclosure that runs with the deed. An avigation easement transfers with property ownership. Requirement of easements will increase the flexibility of developer options, but do not prevent the introduction of noise-sensitive uses into areas of significant noise exposure. Limitations: An easement does not mitigate the noise effects on a property, but rather on the property owner for existing or predicted noise levels. The action often does not change public attitudes to the airport, particularly in regard to growth or airport expansion issues. Implemented by: Local jurisdictions and planning authorities, on behalf of the airport. Public reaction: Property owners often object to the requirements for easements as an effort by local government to place limitations on the desirability of the subject property. An aviation easement required as precondition for approval in another benefit may be perceived as signing away property rights to the airport in exchange for those benefits, which the property owner may feel is owed to them with no strings attached. Example of Technique for Public Information: • Sample Avigation Easement (Raleigh, NC) (184) • Deed of Easement and Declaration of Protective Covenants (Columbus, OH) (185) 9-22 9-21 Land Use Management Techniques for Noise Abatement 139

• Deed of Easement (Sound Insulation Program) (Cincinnati, OH) (186) • Noise and Avigation Easement and Covenant Not to Sue (Scottsdale, AZ) (187) Noise Level/Nuisance Disclosure Statement Purpose: A disclosure policy requires formal disclosure of noise levels of residential property located within the noise impacted areas surrounding an airport, typically the 65 DNL and higher, or within the local flight pattern. The policy is supplemented by information on aircraft noise lev- els distributed by airport staff to citizens, neighborhood associations, developers, real estate agen- cies, and lenders. The policy provides actual, or constructive, disclosure to potential residents in the vicinity of the airport of the likelihood that the property will be subjected to loud aircraft over- flights. Such disclosure is intended to advise a prospective buyer where the property is located in relation to current noise exposure contours, allowing them to make an informed purchase deci- sion. This policy may be implemented by ordinance or through voluntary participation. In the State of Indiana, a public use airport is defined by state law as a public nuisance that is allowed to continue operation without threat of nuisance litigation if the airport is operated in accordance with state aeronautics rules and does not significantly change its hours of operation. Effectively, the State has determined that it is appropriate to exempt airports “in order to reduce the potential for the state to lose the benefits to the state’s air transportation system that are provided by airports” (197). Limitations: Noise Level/Nuisance Disclosure Statements typically are adopted by the local jurisdiction and implemented by real estate agents through listing information or by airport staff through periodic publication of noise exposure maps. Occasionally, an airport will take upon itself the responsibility for direct notification through mailings or signage. Similar to required easements, the required noise level and disclosure statements often do not change public atti- tudes to the airport, particularly in regard to growth or airport expansion issues. Implemented by: Local jurisdictions and/or the airport. Public reaction: The public generally views these types of statements as a ‘taking’ of property because they believe it classifies their property as adversely affected by aircraft noise levels. The legal basis of this argument is, at the time of writing, unresolved. Realtors frequently object because the requirement is seen as a property detriment, impeding sale. Example of Technique for Public Information: • California Real Estate Transfer Disclosure Statement (198) • Public Airport Disclosure Map – Phoenix Deer Valley Airport (199) • Public Airport Disclosure Map – Phoenix Goodyear Airport (200) • Public Airport Disclosure Map – Phoenix Sky Harbor International Airport (201) • Indianapolis Executive Airport Basic Information (202) • Indiana Notice of Designation of Noise Sensitive Area (203) requirements of developers for real estate sales disclosure Development Density Restrictions in High Noise Areas Purpose: In areas of high noise levels, local jurisdictions may prohibit or limit residential land use to minimize noise impacts. Restrictions may include the prohibition of new residential devel- 9-31 9-30 9-29 9-28 9-27 9-26 9-25 9-24 9-23 140 Aircraft Noise: A Toolkit for Managing Community Expectations

opment and specified timeframe for rebuilding if the structure is destroyed from natural causes. Such restrictions may also limit the number of noise-sensitive uses that may be developed within areas of elevated noise through applying a unit per acre factor or a percentage of open use set aside in larger property platting. These measures are usually a provision of a Noise Overlay Zone, but may be applied independently by local government through the platting or subdivision approval process. Limitations: The measure places a restriction on the unrestrained development of property. Although the number of potentially impacted persons is reduced, impacts may still occur within the areas of significant noise exposure. Implemented by: Local jurisdictions. Public reaction: Typically the restriction of development densities is transparent to the ulti- mate resident and land is used for estate lot or agricultural purposes. However, the original devel- oper may be impacted by the limitation the measure places on his ability to fully develop the property. Plat Modifications to Move Open Space into Noisiest Areas Purpose: When development of noncompatible uses is proposed within the areas exposed to significant aircraft noise levels (generally greater than 65 DNL) the plat design may be modified or managed to assure that the areas exposed to the highest noise levels are reserved for open space or buffer zones and the areas exposed to the lower noise levels are used for the most incompat- ible development. Limitations: Such modifications to plats typically require the support or participation of local developers. The acceptance of such a design strategy may be in the hands of those whose poten- tial market and profitably may be adversely affected by such design standards. Implemented by: Local jurisdictions. Public reaction: It is likely that such plat modifications would be transparent to the general home-buying public. Building Code Modifications Purpose: Building codes may be modified to incorporate structural characteristics into a building that will provide additional sound insulation to mitigate the interior noise levels imposed by aircraft activity. In addition to the requirements established for new construction, buildings that are substantially modified or upgraded may be required to be brought “up to code” through the local permitting process. Limitations: Generally, building codes are established at the state level and, depending upon the language contained in the state code, the use of the state building code is either mandated or permissive. “Mandatory” codes are applicable to all construction whether or not they are locally enforced. “Permissive” codes are only applicable if a local government chooses to adopt and enforce the code. Implemented by: Local jurisdictions. Public reaction: Building codes are often unknown to the general public and typically pro- posed changes are challenged by the home building industry. In general, the public attitude toward building code changes/amendments and enforcement is indifference unless there would be a direct impact on their cost. Land Use Management Techniques for Noise Abatement 141

Review of Development Proposals Purpose: Airports can participate with local planning agencies in their review of permit zon- ing and subdivision applications to discourage development of noncompatible land uses. Local planning agencies are encouraged to include airport staff review and airport impact assessment as part of the permitting process. If appropriate land use controls are in place through zoning regulations, airports can deny or recommend changes to a development proposal to ensure com- patibility with airport operations. Limitations: Requires local permitting authority or developers to pro-actively engage airport in the development process. Implemented by: Airports and local jurisdictions. Public reaction: Typically, such administrative actions are unknown to the public. Example of Technique for Public Information: • Phoenix Development Services Department Preliminary Review Checklist – Preliminary Site Plan (204) used by the planning agency to evaluate development proposals • Phoenix Aviation Department development review flowchart for review of land use proposals in airport environs (205) Best Practices in Land Use Management for Noise Compatibility Based upon their effectiveness in managing the use of incompatible lands in the airport envi- rons, as well as the results of surveys and interviews conducted for this analysis, several tech- niques may be identified as best practices. The best practices of land use management are those that preclude incompatible uses before they develop. To assure the best application of each, it is essential that airport staff communicate and collaborate closely with local planning officials that have jurisdiction over the preparation and regulation of each technique. If the incompatible land uses are already present within the areas of significant noise exposure, mitigation actions are war- ranted. The best practices to manage land use include: Acquisition of Noncompatible Property. The acquisition of lands developed in noise-sensitive uses is the surest method to reduce incompatibilities within the areas of significant noise expo- sure, but it is also the most expensive. Property within the 65 DNL contour that has not been developed, but is at high risk to do so, is also a prime target for a comprehensive acquisition pro- gram. In both cases, the purchaser is usually eligible to participate in the federal grant program. Sound Insulation Programs. Sound insulation programs may be best practices in areas where the noise levels are high, the noise-sensitive uses (residences or public-use buildings) are well established, and all available abatement opportunities have been implemented. These programs are expensive and complex to administer, and do not mitigate exterior noise levels, but they do make the interiors of the treated structures compatible with high levels of aircraft noise. Comprehensive Community Planning. The incorporation of considerations of aircraft noise levels into the comprehensive planning process may allow the community to prevent the devel- opment of incompatible uses before they occur. It discourages the provision of infrastructure designed to support residential development in areas where significant potential impacts are now or may become present with development. It also may designate significantly noise impacted areas for future compatible land uses. Comprehensive planning can provide management of the risk to the utility of the airport by stopping incompatibilities before they happen. 9-33 9-32 142 Aircraft Noise: A Toolkit for Managing Community Expectations

Noise impact overlay zoning. The zoning of land that is exposed to significant levels of aircraft noise, whether through conventional zoning or through an impact zone, provides a measure of control over its future development. The greater benefit of the overlay zone is its ability to set density controls, subdivision design requirements, and to require easements, disclosure, and waivers of claim on any property developed within a large area, rather than on each individual zoning request. One drawback to the use of zoning is that it is always subject to changes or vari- ances based on current development considerations and economic need of the community. Subdivision code modification. Because they are transparent, subdivision codes are useful to establish a variety of noise mitigating tools. They may control the density of noise-sensitive devel- opment, impose avigation easements, and require disclosure covenants as conditions of approval. Development review. The collaborative review by airport staff and planning or zoning offi- cials of proposed development projects allows the airport to comment early on about the poten- tial for adverse impacts created by incompatible development on noise-sensitive properties. Organized review may place both the developer and the community on notice that if the incom- patible land use is allowed to take place in areas exposed to high noise levels, conflicts between the airport and the public are likely to arise. Land Use Management Techniques for Noise Abatement 143