pletion of development plans and, equally important, pending the actual provision of sewage treatment facilities adequate to prevent any new development from aggravating pollution problems in the immediate Potomac River watershed. In this regard, the joint powers of the Commonwealth of Virginia governing water quality and those of the county governing land development combine to retard the rate of development and ultimately influence the density of population distribution and basic character of urbanization that may occur. The development plans of the county provide for the distribution of population in major clusters organized to insure that adequate transportation and other public facilities can be provided in strategic locations. Several of the clusters of population range in size from 80,000 to 150,000 persons and are separated by areas of open space, also preserved through public acquisition or other development control, and by areas of much less dense residential development. Planning for large concentrations of population in such clusters enables the incorporation of specific provisions for facilities for the elderly and the younger families which will comprise much of the county's future population. Such clusters also have greater adaptability to future changes in the basic needs of a diversified metropolitan community than can be found in homogeneous tracts of single-family homes developed over large areas at very low densities. Fairfax County has innovated also in the area of land-use control and guiding the rate and character of population growth by establishing both planning and zoning provisions to accommodate the development of the entire new community of Reston, with its projected population of about 75,000. Zoning classification for sites selected by the Reston developer in accordance with both the new community plan and related county plans prepares for eventual orderly development of individual components of the new community at specified population densities. By this method, the county is able to accommodate the developer's needs for public facilities, such as schools, sewers, and water services, on a schedule consistent with the economic necessities of the new community; moreover, orderly growth for a land-use unit of nearly 12 square miles in conformance with the county's plan is assured. On a smaller but nevertheless significant scale, Fairfax County land-use policy affects the distribution of population in the vicinity of Dulles International Airport over an area of several thousand acres on the basis of the public responsibility to protect populations from environmental hazards involved in the settlement of inappropriate locations. It is the explicit adopted policy of the county not to permit housing in several large areas lying within projected noise exposure zones and to discourage housing from being developed in still larger areas of somewhat less noise exposure hazard. These policies will have the effect of redistributing to other more suitable areas of the county several thousand families that would have been housed in these noise exposure zones without the intervention of public policy. North Central Texas (Dallas/Fort Worth) Regional Airport: Major Land Acquisition and Related Environmental Controls The Dallas/Fort Worth region offers an excellent example of how specific public action can affect the distribution of population in a major sector of a rapidly growing metropolitan area. In the 10-county North Central Texas region, centering around Dallas and Fort Worth, the acquisition by the regional airport board of nearly 17,000 acres of undeveloped land, approximately 25 square miles, will effectively change the regional patterns of population distribution permanently. Essentially all of the land upon which the new airport is now being built was equally well suited to housing and related development and lay in the obvious path of sprawling development which was gradually joining the two major cities. At typical residential densities, the airport site itself might easily have accommodated 500,000 people and their typical supporting facilities. Withdrawal of the airport acreage from the metropolitan stock of land available for residential development and accommodating population growth will undoubtedly result in the acceleration of development in other sectors of the metropolitan areas surrounding both Dallas and Fort Worth, partially because the airport provides significant economic stimulus for development. Accordingly, both the rate and direction of population growth in the Dallas/Fort Worth region will be affected significantly by the airport, as will the basic distribution of population between the two cities in what would have been an area of extensive heterogeneous urbanization. Planning for population distribution in relation to environmental effects of Dallas/Fort Worth regional airport is another innovative aspect of the overall airport development project. Although the site acquired for the airport itself is large enough to provide protection against adverse noise exposure to communities in the airport environs, zones of high noise exposure extend substantially beyond the airport boundaries in several directions. These zones overlie several different munici palities, each of which has a vested interest in both the growth and protection of the airport against restrictions that might be imposed by community objections to noise and in the protection of local citizens against adverse environmental effects. Accordingly, the eight municipalities bordering on the regional airport and having areas in which airport noise problems may be expected in the future are adopting local development plans and zoning specifically designed to discourage the growth of housing and similar noise-sensitive land uses in such areas. These local development controls will prevent or severely restrict residential development in several thousand additional acres of the region. Most of this acreage is expected to be held as open space or agricultural use, and accordingly, the substantial additional increment of regional population growth will be distributed to other more suitable locations. In having undertaken the development of the airport and the strategy of protective land-use controls in the surrounding communities jointly, the Regional Airport Board and the communities of the North Central Texas region have set an important precedent for area-wide comprehensive planning not only for a major regional transportation facility but also for population distribution directly related to environmental influences. Flower Mound, Texas: Planned New A planned new community on a site of 6,156 acres with a projected ultimate population of 64,000 now under development in Flower Mound, Texas offers an example of three different types of applications of planning and public policy which may affect population growth and distribution in a major metropolitan area. The Flower Mound new community, a project being undertaken by private developers with Federal financial assistance under the provisions of Title VII of the Housing Act of 1970, seeks to attract a significant portion of residential, commercial, and industrial investment from the metropolitan economy of Dallas and Fort Worth during the next 15 to 20 years. Following land acquisition and preparation of a comprehensive development plan, the developers of Flower Mound have · undertaken a vigorous campaign to promote the project in the interest of attracting new home buyers, industrial developers, and other investors to whom the concept of a planned new community has basic appeal. Because of the popular interest throughout the nation at the current time in new communities (due to the organized alternatives they offer to typically fragmented suburban sprawl), Flower Mound new community expects to provide, in a relatively short time, a focus for several thousand families who otherwise might have located more or less at random in the pattern of suburban dispersal so typical of conventional housing market operations. Thus, the new community offers a higher order of market competition and organization which may offer special attractions sufficient to accelerate and concentrate development forces in a strategic location according to an areawide plan. The Flower Mound new community also exemplifies both the use of Federal incentives provided to developers to attempt such special undertakings within the housing and land development markets and the use of Federal sanctions to prevent the growth of population in areas unsuitable for housing. Flower Mound new community has obtained a commitment from the Department of Housing and Urban Development for an $18 million loan guarantee to support its early stages of development on the one hand, and on the other, it has agreed to defer for 12 years the development of a significant portion of the new community which lies in a projected zone of aircraft noise exposure associated with the new Dallas/Fort Worth International Airport. The agreement to defer development in the noise-exposed area of the new community for a limited time period recognizes the dynamics of both the housing market and efforts to reduce by technological means the noiseoutput of jet aircraft that comprise the national fleet at present. The requirement for deferring development in the noise-exposed sector of the proposed new community was imposed by HUD as a condition to granting the new community loan authorization and could well have the effect of preventing the premature construction of between 3,000 and 5,000 dwellings in an area where environmental hazards are a distinct possibility. Los Angeles County: Removal of Incompatible Land Uses Frequently, the pressures of sheer population growth result in patterns of development in which functional conflicts between established land uses become so acute that remedial action must be taken to remove one of the sources of conflict. Increasingly, it is becoming necessary to relocate people in significant numbers in order to resolve such conflicts even temporarily. The relocation of approximately 1,000 families in housing located too close to Los Angeles International Airport to be compatible with the noise of jet aircraft is a case in point. Following World War II, unplanned growth in Inglewood, California and other communities close by Los Angeles International Airport, together with steadily increasing volumes of commercial jet aircraft traffic at the airport, has exposed several square miles of airport environs in Los Angeles County to noise conditions that have become intolerable for many residents. The noise of aircraft approaching Los Angeles International Airport has caused such severe interference with educational activities that two relatively new schools in the immediate environs of the airport have been abandoned. Extensive litigation has resulted in numerous judgments against the airport for damages to property whose homes decreased in value and marketability under the influence of aircraft noise. Accordingly, airport authorities resorted to the extreme remedial measure of acquiring by negotiation or eminent domain slightly over 1,000 parcels of land in the immediate environs of the airport in order to remove existing housing and incorporate the acreage into the airport site. One objective of this land acquisition was to insulate the distance between the aircraft and other housing in the built-up area just beyond, thereby forestalling further complaints from residents exposed to high levels of noise from approaching and departing aircraft. The land-acquisition program has extended over several years and to date has succeeded in clearing only about 200 acres of land at a cost of over $50 million. While the total population redistributed by this painful process may seem insignificant in relation to the general concentrations in the Los Angeles metropolitan area, the case is particularly significant for providing perspective on the community costs of failing to plan adequately for population distribution and development control in relation to environmental factors characteristic of nearly every major metropolitan area. The foregoing examples illustrate some of the actual and potential benefits of coupling the analytical and creative capabilities of a contemporary planning process with effective political leadership. Giving close attention to population distribution within major metropolitan area is primary public business. Both the necessity to focus on population density and distribution as matters of public policy and the means to do so are provided by the contemporary institutions of urban planning. A perspective for each metropolitan area and its interrelated growth and development problems is available in most areawide planning agencies; and specific options for public policy on population distribution are suggested by the plan-making process that such agencies conduct. OPPORTUNITIES FOR IMPROVING The spate of legislation and other Federal actions in the past two years directed toward the relief and prevention of environmental problems is an encouraging indication that the time may have come for an era of intensified urban planning activity. The Housing Act of 1970, the National Environmental Policy Act of 1969, and the Airport and Airways Development Act of 1970 hold great opportunities for a national investment in planning implementation in at least equal measure with the investment already made in forming institutions and planning agencies, gathering data, formulating and elaborating development alternatives, and engaging in urban research. The thrust of each of these new laws and the programs they engender will be enhanced by the availability of the nation's institutional base for planning. Each of the aforementioned new laws provides a reinforced mandate for growth and development planning, as well as new tools and funding. The Housing Act of 1970 and the Airport and Airways Development Act of the same year have especially important potential for becoming instruments of metropolitan and regional growth planning in that they create significant "targets of opportunity" in the form of entire new communities and vitally needed new and expanded airports. New communities, such as Reston, Virginia and Columbia, Maryland or the entire Irvine Ranch in Orange County, California, have served to demonstrate the benefits of thorough and continuing planning for development. These and other new communities have given the American public practical models of organized urban development in clear contrast with the dehumanizing pattern of postwar suburban sprawl. The new communities provisions of the 1970 Housing Act provide timely incentive and support for a significant trend away from the traditional process of urban growth. The scope of metropolitan and regional planning should include specific identification and promotion of sites suitable for new community development in order to encourage the growth and activities of organizations capable of carry. ing such projects out. The Airport and Airway Development Act, in contrast to the Housing Act and its provisions for planning, presents both challenge and opportunity for planning agencies at every level of government. The challenge arises from the fact that most major airports have been only peripherally involved in comprehensive development planning, and there exists less institutional capability in the aviation industry to participate easily in the multilevel public process of planning for urban growth. It should be recognized, therefore, that planning programs for metropolitan areas in which airport expansion or site-selection problems exist will probably have to provide special resources in support of the airportdevelopment planning process. In a recent joint publication, the Federal Aviation Administration and the Airport Operators Council International affirmed the essential characteristics and implications of metropolitan airports as follows: The airport system must be recognized as a key element in metropolitan planning and development, by virtue of its nature as a major consumer of urban land, a principal environmental influence, an important stimulant to intensive urban development, and a significant consumer of ground transportation services.19 Other encouraging evidence of a potentially favorable climate of public opinion for growth and development planning is apparent in the formation of the Environmental Protection Agency, the Council on Environmental Quality, and the President's Domestic Affairs Council. The emergence of these new elements of government clearly reflect a traditional pattern of response to a popular crisis widely perceived-the environmental/ecological crisis. These new agencies mainly provide the machinery for response to dangerous conditions and trends that are plainly the result of short-sighted industrial and governmental practices affecting the use of basic natural resources. Most of the present cases of extreme water pollution could have been predicted by a simple projection of trends evident nearly half a century ago, and indeed many were. It is ironic that in 1970 it is a law enacted in 1899 that provides the basis for current Federal action by the Environmental Protection Agency to halt industrial practices of discharging toxic wastes into natural waterways. But in both their formation and enforcement activities, the admirable new environmental protection and control agencies are more akin to a posse than to a planning body. Their project review activities provide feedback valuable in any ongoing process of planning; but, by their very nature, such ex post facto reviews and litigation can only hope to refine proposals for the development of separate and relatively simple systems of facilities generated much earlier by the interaction of many other forces acting independently and frequently in competition for the same resources. Clearly such review and enforcement activities can contribute to the pressure for applying improved technology in the local planning process, but they cannot take the place of planning activity oriented toward changing basic patterns of settlement or resource consumption in pursuit of long-term environmental improvement. In addition to responding to obvious current environmental crises, the new enforcement and salvage agencies must yet face the fact that some of the most disturbing implications of population growth trends now projected are those for the quality of future urban environments. The further concentration of population in metropolitan areas is fairly certain to produce chronic shortages of power for basic heating, air conditioning, recreation, and industrial uses. Despite declining residential densities, the sheer magnitude of major concentrations of single homes and garden apartments is enough to produce microclimatic effects, including both concentrations of heating-system exhaust gases and elevated temperatures, over significant land areas. At the same time, in the absence of long-delayed improvement in noise-suppression technology and law enforcement, ambient noise levels in most metropolitan areas may be expected to rise as a result of increased aviation operations, high-speed truck and automobile traffic, and both industrial and residential applications of noisy machinery, such as air conditioners, compressors, mowers and saws. The World Health Organization has estimated that the general ambient noise level in major western cities has been rising at the rate of about one decibel each year since 1961.20 Given the typical daytime noise levels in many major cities in 1970, this rate of increase in noisiness will be sufficient to assure the end of unamplified voice communications in many city streets before the end of the century. Such predictions are important in planning because of their sobering effects, of course, but more fundamentally because they provide much of the basis for anticipating the emergence of even more widespread public interest in improved population distribution as one approach to environmental quality control. Basic public concern now evident in the current popularity of such issues as environmental degradation and disruption of natural ecological systems underscores the need for urban growth and development policies of national scope. Much, if not most, of the factual and ideological foundation underlying the current public concern for the environment, ecological systems, and the consequences of uncontrolled growth has evolved directly from the basic substance of the fields of urban and regional planning during the past half century. Indeed, for professionals and many others familiar with the actual history of urban planning in the United States, the upsurge of public concern and enthusiasm for a whole range of "new" issues, including environmental quality, ecological dysfunctions, urban sprawl, civil rights, and social reform, is an auspicious indication that the 1970's may be the era in which urban planning may well achieve a degree of political commitment commensurate with its practical benefits and basic intellectual appeal. Opportunities to approach or achieve the objectives of environmental quality control, and in some cases, actual salvage, are likely to be either very small in scale, numerous, and available in the relatively near future, or very large in scale, scarce, and available only in the long-term future and under a variety of conditions that may be difficult to achieve. It is important, therefore, not to expect too much of the intriguing long-range proposals for redistribution of major proportions of the United States population. It is equally important, however, not to discount the potential cumulative effects of applying population distribution logic in planning and development situations of less than heroic magnitude in the immediate future. It is useful to consider the characteristics of these types of opportunities to plan for population distribution separately. Microscale In relation to either the territory of the continental United States or the size of its population, the majority of opportunities to plan effectively for population distribution are relatively microscopic. Nevertheless, these opportunities in the aggregate may well account for 80 percent of the area to be urbanized in the course of the next 30 years. In addition to the practical necessity of dealing with development in minute increments until larger and larger units are brought within the management and planning capability of competent government and private enterprise, there is a potentially very high symbolic value in demonstrating the efficacy of managing population growth and urbanization. through the careful and precise application of planning principles in certain critical, although relatively small, areas. The key to planning for distribution of most of the population growth to be expected in the next 30 years lies in controlling the location and density of housing in the major metropolitan areas. While this may appear to be a truism, the fact remains that very little systematic planning is done to control either the timing or the direction of housing development at a scale even closely approximating a metropolitan area. Even housing density controls, which may have profound implications for the quality of life after basic land-use decisions have been made, are rarely, if ever, conceived or applied in pursuit of any scheme of development objectives beyond the scale of a single municipality, much less in pursuit of a strategy or plan for metropolitan area growth. Only recently, with the recognition of the discriminatory effects of individual zoning ordinances in many metropolitan areas by state and Federal courts, have metropolitan area planning agencies been authorized and funded to conduct areawide analyses of housing patterns and conditions in order to formulate development policies in keeping with the scale of the typical metropolitan housing market. Small-scale opportunities to affect population distribution and density are available every day throughout the United States in local legislative actions to adopt or reject proposed changes in zoning. Zoning is the principal and nearly universal method of land-use and density control employed by local government. At least 100,000 zoning changes affecting population distribution and density are made each year by local legislative actions. While many of these are so small in scale as to have a negligible effect on overall patterns of settlement at the metropolitan level, a majority of such changes made in the suburban communities involve the initial public permission to develop "raw" land for residential, industrial, or commercial use which in turn attracts still further development. All such zoning changes constitute the calculus of change in population distribution and directly affect the character and quality of the local environment permanently for all practical purposes. It is important to recognize that the fragmentation of metropolitan areas into many municipalities, each with the power to zone its own land, effectively prevents the organization or coordination of local zoning changes to implement some strategy for population distribution or the character of development on an areawide basis. Accordingly, metropolitan areas have grown by a process of incremental accretion. In recent years, the pressures for controlling urban growth in the interest of reducing congestion, realizing economies, and preventing aggravated pollution problems have caused many of the larger municipalities, and particularly, urbanizing counties, to prepare and adopt comprehensive development plans which include zoning strategies coordinated with programmed public-utility construction. Because of the fact that economies of scale have forced the building industry to deal in increasingly larger units of land and through larger organizations for both construction and financing, public agencies, such as municipalities, equipped with competent development plans and specific controls have increasing leverage in their attempts to regulate the course of development and population distribution in balance with environmental, ecological, and economic development objectives. So long as the units of land exist in which both speculation and actual development remain fragmented and relatively small, however, it will be essential for public bodies responsible for planned development to deal carefully with each proposed zoning change and development proposal submitted and to evaluate each one within the context of a comprehensive plan for population distribution and the provision of all necessary services. This process of zoning and development proposal in the context of such a plan demands that public goals for growth and development be clearly articulated and, perhaps even more important, that the political decision-making process be prepared to accept the discipline of planning for population growth and distri |