OPINION BY JUDGE CRUMLISH, JR., July 25, 1975:

Consolidated for disposition are the appeals of landowner-developers and intervening protestants from an order of the Court of Common Pleas of Chester County invalidating Ordinance No. 267 of Tredyffrin Township under which landowners were granted preliminary approval of a development known as Chesterbrook in Tredyffrin Township and building permits to begin construction of an initial phase of Chesterbrook (Nos. 1322 and 1323 C.D. 1974), and which further denied intervening protestants' standing to challenge the allegedly exclusionary impact of Ordinance No. 267 in failing to affirmatively provide for low income housing (No. 1386 C.D. 1974).

These appeals, although generating a record of massive proportion and involving the development of more than 850 acres of Tredyffrin Township in Chester County, do not require a detailed history to frame the legal issues raised. In December of 1970, Tredyffrin Township (Township) amended its comprehensive plan to designate a 1,000 acre portion of the Township as a Unified Development Area (U.D.A.). The objective of the U.D.A. designation was to have "this area planned as an entity and developed over a period of years in accordance with a unified plan, rather than on a lot-by-lot, piece-meal subdivision basis. Basic components of the U.D.A. would be the retention of broad bands of open space along the many stream valleys in the area; a large percentage of the area devoted to other open space uses such as playgrounds, play fields, swimming pools, tennis courts, and golf courses; a mix of lot sizes and dwelling types; community uses such as schools, and a library; convenience neighborhood shopping areas; and such other uses as are determined to be desirable components of a high quality and economically viable community." Five months after the public announcement of the amendments to the comprehensive plan, Richard J. Fox, Greenview Associates and Picket Post Village, Inc. (hereinafter "Fox"), as legal or equitable owners of a substantial portion of the land designated within the U.D.A., applied for a rezoning of its land from R-1/2 Residential to five zoning districts extant in other areas of the Township, ranging from RC-Rural Conservation (recreational open space) to C-2 Commercial (retail and light commercial), to enable it to develop a project of mixed residential and commercial uses as envisioned by the comprehensive plan. This planned development became known as Chesterbrook. Fox proposed the development of Chesterbrook over a ten year period to contain 177 single family, detached dwellings clustered on 135.6 acres; 1238 townhouses on 137.5 acres; 1590 garden apartment and mid-rise apartment units on 247.3 acres; office, motel and community retail and recreational facilities on 135.5 acres; with the remainder of the tract to be preserved as open space and proposed school sites.

The Board of Supervisors referred the Chesterbrook rezoning application to the Planning Commission for its recommendations, and numerous hearings and executive sessions were held thereafter by both bodies in an attempt to hammer out the details of the plan and to obtain commitments from the developer. The first legislative implementation of the U.D.A. concept occurred in November of 1971 when Ordinance No. 264 was enacted. This ordinance added section 2003 to the Township zoning ordinance, setting forth in some detail the content requirements of a developmental plan submitted for U.D.A. consideration, and the respective duties of the Planning Commission and Board of Supervisors in reviewing these plans. Subsection 4 of 2003 binds a developer to the plan submitted for approval together with the requirements of the standard use district if the zoning ordinance is amended to accommodate the plan. On March 12, 1972, the Board of Supervisors enacted Ordinance No. 267 adopting the Chesterbrook proposal en toto, together with certain commitments made by Fox which were a matter of record.

Timely appeal from the adoption of Ordinance No. 267 was taken to the Court of Common Pleas of Chester County by two residents of the Township and a civic group calling itself Citizens Organized to Reclaim Chesterbrook (hereinafter collectively referred to as CORC). The disposition of this appeal was postponed by stipulation of the parties, however, to enable Fox to apply to the zoning officer for a preliminary opinion of Chesterbrook's consistency with Ordinance No. 267, and to apply for subdivision approval and building permits for the R-1 portion of Chesterbrook. Upon Fox's receipt of these approvals, CORC appealed to the Township Zoning Hearing Board (zoning board). Main Line Housing Improvement Corporation, Main Line Community Association, and numerous individuals alleging to be residents of the Township who either lived in substandard housing and desired to reside within Chesterbrook if subsidized housing were provided or who desire low-income housing to be provided within Chesterbrook, and non-residents of the Township who lived in substandard housing and desired to live in Chesterbrook were low-income housing provided (hereinafter collectively referred to as "Main Line," unless otherwise indicated), were thereafter permitted to intervene as appellants before the zoning board. Main Line simultaneously filed a cross complaint against the Township and Board of Supervisors alleging an exclusionary effect of Chesterbrook and Ordinance No. 267 because it failed to provide for low income housing. On May 16, 1973, the zoning board upheld Ordinance No. 267 and the permits issued to Fox thereunder. CORC and Main Line appealed to the Court of Common Pleas which consolidated the appeals with CORC's prior procedural appeal. On September 30, 1974, the lower court reversed the zoning board, invalidating Ordinance No. 267 under Eves v. Zoning Board of Adjustment, 401 Pa. 211, 164 A.2d 7 (1960), because it failed to provide sufficient standards to guide the Board of Supervisors' determination of the uses and the location of uses permitted within the U.D.A. The court also denied standing to Main Line on the ground that they failed to establish that they had ever applied for a permit in the Township or were otherwise adversely affected by the enactment of Ordinance No. 267. Both Fox and Main Line appealed these determinations to this Court, and a limited supersedeas of the lower court's order in 1322 and 1323 C.D. 1974 was granted on November 27, 1974.

Since the court below did not take additional evidence, our scope of review, as was that of the lower court, is limited to a determination of whether the zoning board abused its discretion or committed an error of law. Camaron Apartments, Inc. v. Zoning Board of Adjustment of Philadelphia, 14 Pa. Commw. 571, 324 A.2d 805 (1974), Surrick v. Upper Providence Township Zoning Hearing Board, 11 Pa. Commw. 607, 314 A.2d 565 (1974). Because the Fox appeals and the Main Line appeal involve distinct challenges to the validity of Ordinance No. 267, we will discuss each separately.

Nos. 1322 and 1323 C.D. 1974

The Fox appeals raise three issues for our determination:

1) Is Ordinance No. 267 invalid because it fails to provide adequate standards by which the Board of Supervisors could determine the classification, density and location of uses permitted in a U.D.A.?

2) Can the U.D.A. concept envisioned by the Township's comprehensive plan be effectuated by standard zoning under Article VI of the MPC, or was the Township required to proceed under the Planned Residential Developments (PRD) provisions contained in Article VII of the MPC?

3) Did the Board of Supervisors have sufficient evidence of the potential environmental impact of Chesterbrook before it when it enacted Ordinance No. 267?

The lower court invalidated Ordinance No. 267 solely on the basis of the Supreme Court's decision in Eves v. Zoning Board of Adjustment, supra. A review of Eves, however, reveals an entirely dissimilar situation from the instant appeal. In Eves, the Court had before it a "flexible selective zoning" scheme which created in some detail an F-1 Limited Industrial District, but did not affix the boundaries of the district to any area in the township. The district was thus allowed to "float," coming to earth only upon the application of a landowner who had the requisite acreage for a rezoning of his property to F-1. This zoning scheme was invalidated because it 1) was not in accordance with a comprehensive plan; and 2) gave the township supervisors unfettered discretion in determining appropriate land uses on a case-by-case basis. Without discussing the limitation of the Eves "in accordance with a comprehensive plan" holding by subsequent decisions, there can be no question that Ordinance No. 267 specifically implements the U.D.A. concept established by the 1970 amendment to the Township's comprehensive plan, and specifically brings to earth the uses permitted within the U.D.A. Any contention that Ordinance No. 267 fails to provide adequate standards for the Board of Supervisors to pass upon individual applications for land development within the U.D.A. overlooks the fact that the ordinance simply applies five standard districts then extant in other areas of the Township to specific portions of the U.D.A. as delineated in the Chesterbrook proposal. In developing Chesterbrook, Fox must comply with the requirements of the standard zoning districts delineated in the zoning ordinance as well as the additional commitments made as a part of its application for a rezoning. Suffice it to say, that these requirements are specific and comprehensive and adequately guide the appropriate zoning and planning bodies of the Township in considering further applications by Fox for zoning approvals within Chesterbrook.

The real thrust of CORC and the lower court's difficulty with the planning process resulting in Ordinance No. 267 is that prior to Fox's application for a rezoning there was no way of determining the specific uses and the location of such uses which would be permitted within a U.D.A. This contention, however, misapprehends the function and standards required of a comprehensive plan as distinguished from a zoning ordinance implementing a comprehensive plan. As this Court said in Morelli v. Borough of St. Mary's, 1 Pa. Commw. 612, 617, 275 A.2d 889, 891-892 (1971): "The comprehensive plan does not have the legal effect of a zoning ordinance, which actually regulates the land use as may be recommended by the comprehensive plan. The planning commission may recommend all kinds of desirable approaches to land utilization and development. Not all of these may become eventually legally enforceable in a zoning ordinance. In other words, a comprehensive plan is abstract and recommendatory, whereas the zoning ordinance is specific and regulatory." Such a pattern of planning and rezoning was carefully followed here. The U.D.A. designation added to the comprehensive plan in 1970 established for the specific area in question "general guideposts and guidelines . . . for the guidance of zoning policy," Cleaver v. Board of Adjustment, 414 Pa. 367, 377, 200 A.2d 408, 414 (1974); and Ordinance No. 267 effectuated these policies by creating fixed geographic districts of specific use classifications. The fact that Fox initiated the rezoning and Ordinance No. 267 essentially adopts the Chesterbrook proposal does not put the "zoning cart before the planning horse" as suggested by CORC. As a practical matter, many rezonings occur upon the request of a landowner, and these rezonings are not invalid so long as they do not amount to spot zoning or special legislation, and they otherwise conform with the spirit of the comprehensive plan. Village 2 at New Hope, Inc. Appeals, supra; Marino v. Hearing Board of Harrision Township, supra.

Nor do we find persuasive CORC's argument that the U.D.A. zoning, as conceived by the Township's comprehensive plan and implemented by Ordinances Nos. 264 and 267, exceeded the Township's standard zoning powers under Article VI of the MPC, 53 P. S. § 10601 et seq. The thrust of this argument is that the U.D.A., envisioning an integrated, multi-use "mini-town" ordinarily developed as a PRD, can only be effectuated under the procedures of Article VII of the MPC, 53 P. S. § 10701 et seq., dealing with PRDs. We will not dwell upon this contention for long because CORC, once again, overlooks the fact that Ordinance No. 267 does not create multi-use zoning districts. Rather, the ordinance designates specific areas of the U.D.A. as single-use districts conforming to the requirements of standard zoning classifications already existing in the Township. This is entirely consistent with the zoning powers authorized by Article VI, and we agree with the lower court that the Legislature did not manifest an intent to limit innovations in standard zoning, such as a U.D.A., by the enactment of Article VII.

CORC finally challenges Ordinance No. 267 on the ground that the Board of Supervisors had insufficient information relative to the environmental impact of Chesterbrook prior to undertaking the rezoning. Although the lower court did not reach this issue as it held Ordinance No. 267 invalid under Eves, it did indicate that evidence of the impact of Chesterbrook on Valley Forge State Park and the immediate vicinity was sorely lacking, and it would have been inclined to remand to the zoning board for additional evidence. We have carefully reviewed the record before us and find more than substantial evidence to sustain the zoning board's findings in this regard. Prior to the enactment of Ordinance No. 267, Fox presented to the Board of Supervisors a detailed environmental synthesis of the site, including studies dealing with the prevention of erosion and flooding during the construction stages and as Chesterbrook is developed, the location and treatment of open space to preserve natural vegetation, and the prevention of further pollution of the streams running through Chesterbrook. Fox has made binding commitments for the preservation of historic buildings within Chesterbrook, the construction of retention basins to minimize surface flooding and the protection of recreational facilities within the flood plain. As this Court stated in Payne v. Kassab, 11 Pa. Commw. 14, 29, 312 A.2d 86, 94 (1973): "(Article I), Section 27 was intended to allow the normal development of property in the Commonwealth, while at the same time constitutionally affixing a public trust concept to the management of public natural resources of Pennsylvania. The result of our holding is a controlled development of resources rather than no development." Similarly, the Board of Supervisors here was faced with the inevitable development of the tract within the U.D.A., and the choice at the preliminary stage of considering a rezoning was whether the Chesterbrook proposal gave reasonable assurances of a minimum adverse impact to the environment. From this record, we cannot say that the Board erred in this respect. Further assurance of an environmental sensitivity is adequately provided by the Township's subdivision regulations and the environmental protection laws of this Commonwealth with which Fox must comply in order to obtain sewer, water, erosion and siltration, and building permits as the developer of Chesterbrook progresses.

In sum, we conclude that Ordinance No. 267 is valid as conforming with the comprehensive plan, provides sufficient standards to guide the approval of developments thereunder, is authorized under Article VI of the MPC, and reflects a reasonable consideration of the environmental impact of the uses permitted thereunder.

No. 1386 C.D. 1974

The Main Line appeal presents a broad frontal attack upon the constitutionality of the entire zoning of the Township as allegedly exclusionary of poor people, and specifically upon Ordinance No. 267 as continuing this allegedly exclusionary policy by failing to require the developer to affirmatively provide for low-income, governmentally subsidized housing. Before addressing these issues, however, we must determine whether appellants making up Main Line had standing to appeal, i.e., whether any is an "aggrieved person" within the meaning of Section 1005 of the MPC.

The lower court found it unnecessary to differentiate between the respective interests of the civic associations and the resident and non-resident appellants composing Main Line because it was not alleged that any of these parties had ever applied for a permit to develop low-income housing within the Township, or that Ordinance No. 267 had been enacted or enforced to their detriment. We believe that this view construes too narrowly the requirements of standing, and merges standing with another aspect of justiciability, i.e., the ripeness of a constitutional challenge to a zoning ordinance. In each of the decisions relied upon by the lower court, the determinative issue was not the standing of the particular litigant, but whether the court could decide a constitutional challenge to an ordinance in vacuo, before it had been actually applied to a litigant and without the benefit of a specific developmental plan proposed by the litigant. Here, there can be no question of the ripeness of Main Line's attack. Fox obtained preliminary approval of the Chesterbrook development contemplated by Section 1005 (b) of the MPC, 53 P. S. § 11005(b), thus keying the thirty day period in which an appeal challenging the substantive validity of the underlying ordinance could be taken by protestants. Additionally, a permit was obtained by Fox for the first stage of residential construction in the northeast corner of Chesterbrook. These events were enough to concretely frame the constitutional issues involved.

We have little difficulty concluding that the residents of the Township, especially those presently living in substandard housing appealing in their own behalf or as members of the civic associations composing Main Line appellants, have a sufficient interest in the outcome of this litigation to have standing. It has traditionally been held that residents of a municipality have a legal interest in preserving the integrity of their zoning ordinance and the status of their property thereunder so as to be "aggrieved persons," thereby enabling them to challenge an amendatory ordinance as unconstitutional. See Roeder v. Hatfield Borough Council, supra; Penny v. Warrington Township Board of Supervisors, 21 Bucks C.L. Rep. 322 (1971); Tredyffrin Construction Company Appeal, 7 Ches. Co. Rep. 153 (1956). Having decided the resident appellants composing Main Line have standing, the remaining appellants would have derivative standing, and our prior decisions relative to the standing of non-residents and civic associations are not determinative of this appeal. We therefore reach the merits of Main Line's attack.

The crux of Main Line's challenge is that the Township's zoning is exclusionary in that it fails to provide for its "fair share" of housing opportunities for low and moderate income persons under Concord Township Appeal, 439 Pa. 466, 268 A.2d 765 (1970); Girsh Appeal, 437 Pa. 237, 263 A.2d 395 (1970); National Land and Investment Co. v. Easttown Township Board of Adjustment, 419 Pa. 504, 215 A.2d 597 (1965); Township of Willistown v. Chesterdale, 7 Pa. Commw. 453, 300 A.2d 107 (1973). See also Southern Burlington County N.A.A.C.P. v. Township of Mount Laurel, 67 N.J. 151, 336 A.2d 713 (1975). Assuming that we hold the Township's zoning to be exclusionary, Main Line argues that the "fair share" concept be implemented by requiring Fox to affirmatively allocate and develop a portion of Chesterbrook as low moderate income housing units, or that the Township be ordered to plan and zone for such housing.

We do not decide the question of the appropriate remedy here, however, as we cannot agree that the Township is exclusionary when considered in light of the rezoning achieved by Ordinance No. 267, adopting the Chesterbrook proposal. At best, the record establishes that over the past decade the percentage of low income (and minority) residents of the Township has declined, while the development proceeding in the Township has been in the nature of single-family dwellings and apartments affordable by persons of above average income. The evidence, however, does not establish that this direction in suburban growth is attributable to the zoning of the Township. Rather, it would appear to be attributable to the high cost of land and accessory services common to municipalities within access of the Philadelphia metropolitan area. This basic fact of life does not render the zoning of the Townshop exclusionary. Upper St. Clair Township v. Commonwealth, 13 Pa. Commw. 71, 317 A.2d 906 (1974). Given the high density, multiple-family uses permitted under Ordinance No. 267, which at the time the Chesterbrook development was approved provided for housing units for as low as $18,000.00, we can only conclude that Main Line has failed to sustain its burden of proving the Township's zoning to be exclusionary.

Consistent with the foregoing, we reverse the order of the court below in the appeals docketed at 1322 C.D. 1974 and 1323 C.D. 1974, and affirm the dismissal of the appeal docketed at 1386 C.D. 1974.