CORDY, J.

This action arises from the Department of Environmental Protection's (department's) issuance of a waterways license under G. L. c. 91 (chapter 91 license) to the Boston Redevelopment Authority (BRA) to redevelop a section of land owned by the BRA on the seaward end of Long Wharf (project site). The plaintiffs, ten residents of Boston's North End neighborhood, appealed the issuance of the chapter 91 license to the department's office of appeals and dispute resolution, and ultimately to a judge in the Superior Court, claiming the department acted unconstitutionally and beyond its statutory authority when it issued the chapter 91 license without obtaining a two-thirds vote of the Legislature as required by art. 97 of the Amendments to the Massachusetts Constitution.3 On cross motions for judgment on the pleadings, the motion judge ordered declaratory relief and issued a writ of mandamus ordering the department to enforce art. 97. We granted the BRA's application for direct appellate review. We are presented with two principal questions: Whether the project site, which the BRA took by eminent domain for urban renewal purposes, is subject to art. 97; and if art. 97 does apply, whether the department may issue the chapter 91 license to the BRA without triggering the requirement of a two-thirds vote of the Legislature. We conclude that the project site is not subject to art. 97.4

1. Background. a. The BRA and the 1964 urban renewal plan. The BRA is both a "redevelopment authority" under G. L. c. 121B, § 4, and an "urban renewal agency" under G. L. c. 121B, § 9.5 Additionally, it serves as the planning board for the city of Boston and monitors private development under G. L. c. 121A. See St. 1960, c. 652, §§ 12-14.

The BRA's urban renewal powers and duties are enumerated throughout G. L. c. 121B, particularly in § 11 and §§ 45-57A. The legislative goals of G. L. c. 121B are to "eliminat[e] decadent, substandard, or blighted open" areas and to promote sound community growth. G. L. c. 121B, § 45. See G. L. c. 121B, § 1 (defining decadent, substandard, and blighted open areas). The BRA is vested with the authority to effectuate the goals of urban renewal through land assembly, title confirmation, public financial assistance, and development and design controls, all of which enable the BRA to guide private sector development toward areas in need. See G. L. c. 121B, §§ 46-57A. Perhaps the most significant power granted to the BRA is the power of eminent domain, which G. L. c. 121B confers on the BRA as is "necessary or reasonably required to carry out the purposes of [c. 121B]," G. L. c. 121B, § 11 (d), such purposes being the elimination of "decadent, substandard or blighted open conditions." G. L. c. 121B, § 45.6

Pursuant to the Downtown Waterfront-Faneuil Hall urban renewal plan, dated April 15, 1964 (1964 urban renewal plan), and an order of taking, dated June 4, 1970, which incorporated that plan, the BRA acquired the project site in 1970 as part of a larger taking by eminent domain of the Long Wharf area (1970 taking). In accordance with the legislative goals of G. L. c. 121B, the 1964 urban renewal plan provides in Section 201:

b. The project site. The project site is a section of land at the eastern end of Long Wharf on which sits an open-air brick structure known as Long Wharf Pavilion. The BRA continues to hold and maintain Long Wharf, including the project site, pursuant to the 1964 urban renewal plan.8 Long Wharf is a designated national historic landmark, and is the site of water transportation, public transportation, hotels, retail establishments, and restaurants. It is also part of the Boston Harborwalk, a pedestrian walkway that lines the waterfront.

In 1983, the department9 permitted the Massachusetts Bay Transportation Authority to construct an emergency egress and ventilation shaft for the Blue Line subway tunnel, to be capped off by the structure now known as Long Wharf Pavilion. At the same time, the BRA undertook renovations to the plaza area surrounding the pavilion. The plaza measures approximately 33,000 square feet, is paved with granite flagstones, and features a large inlaid compass rose to the south of the pavilion. Other features include benches, public binoculars, and a flag pole. A segment of the Harborwalk lines the perimeter of the plaza. Although not discussed in much detail in the 1964 urban renewal plan, the plaza's current use is consistent with the plan's provision for an "observation platform" on Long Wharf.

In addition to the 1964 urban renewal plan, the project site is also subject to Boston's Municipal Harbor Plan, which was approved in 1991 by the Secretary of the Executive Office of Environmental Affairs pursuant to 301 Code Mass. Regs. §§ 23.00 (2000) (municipal harbor plan). Among other objectives, the municipal harbor plan calls for the activation and revitalization of Boston's underutilized shoreline "by promoting growth through private investment that is appropriately designed, and is a balanced mix of uses that bring vitality to the waterfront and public benefits and amenities that are shared by all Boston residents." The municipal harbor plan was designed to complement waterways regulations that accompanied G. L. c. 91, already applicable to much of the waterfront area.

Considering the project site to be underutilized, the BRA proposed a plan in 2008 to redevelop it by enclosing and expanding the pavilion to accommodate a restaurant with outdoor seating, "takeout service," and a bar. Specifically, the BRA planned to expand the 3,430 square foot pavilion by 1,225 square feet. In addition to the restaurant, the proposed redevelopment includes shaded seating, restrooms, and several sets of binoculars, all available to the public independent of patronage of the restaurant. The proposed redevelopment is intended to allow year-round use of the pavilion and provide facilities and seating to the large number of pedestrians and water transit users who frequent the area.

The BRA obtained fourteen zoning variances from the Boston zoning board of appeals that allow for live entertainment, "takeout service," and food and alcohol service until 1 A.M. at the proposed restaurant. In addition, because the project site is located on filled tidelands, the BRA was required to obtain the chapter 91 license from the department. See G. L. c. 91, § 14; 310 Code Mass. Regs. §§ 9.00-9.55 (2012). See also Moot v. Department of Envtl. Protection, 448 Mass. 340, 342 (2007), S.C., 456 Mass. 309 (2010) (discussing applicability of G. L. c. 91, which governs development on tidelands).

The department granted the chapter 91 license to the BRA on September 17, 2008. The plaintiffs appealed. They argued that the proposed restaurant would create unnecessary noise and would damage public open space, parkland, and scenic quality.10 On January 29, 2010, the commissioner of the department issued a final decision affirming the issuance of the chapter 91 license.11 The plaintiffs appealed from that final decision to the Superior Court, seeking a declaratory judgment under G. L. c. 231A and a writ of mandamus under G. L. c. 249, § 5, ordering the department to enforce the requirements of art. 97 by seeking a two-thirds vote of the Legislature prior to issuing the license. The motion judge concluded that because the 1964 urban renewal plan aimed to create parkland, open space, and a means of utilizing and enjoying the harbor, it served art. 97 purposes and was therefore subject to art. 97. The judge further concluded that the issuance of the chapter 91 license constituted a transfer of legal control from the department to the BRA sufficient to effect a disposition, as well as a change in use of the land, both of which triggered the two-thirds vote requirement. Accordingly, the judge granted the plaintiffs' requested relief.12

On appeal, the plaintiffs contend that the project site is subject to art. 97, and that the department's issuance of the chapter 91 license constituted a use or disposition triggering the two-thirds vote requirement. The BRA counters that art. 97 does not apply because the project site was not taken for art. 97 purposes. The department argues that it lacks the authority to interpret and apply art. 97, and that even if art. 97 did apply, the department's issuance of the chapter 91 license did not constitute a use or disposition triggering the vote requirement. Both defendants argue that the motion judge improperly voided the chapter 91 license through declaratory and mandamus relief.

2. Discussion. a. Applicability of art. 97. Article 97 was approved and ratified on November 7, 1972, superseding art. 49 of the Amendments. See note 3, supra. It provides, in pertinent part, as follows:

The principal issue in this case concerns whether the project site, which the BRA took by eminent domain in 1970, was "taken" for art. 97 purposes. See Selectmen of Hanson v. Lindsay, 444 Mass. 502, 504-506 (2005) (in order for art. 97 vote requirement to apply, land must have been taken or acquired for art. 97 purposes). Article 97 clearly states that its purposes are "the conservation, development and utilization of the agricultural, mineral, forest, water, air and other natural resources." In contrast, land taken for urban renewal purposes is generally understood to be taken "for the purpose of eliminating decadent, substandard or blighted open conditions." G. L. c. 121B, § 45. See Aaron v. Boston Redev. Auth., 66 Mass.App.Ct. 804, 807, 808, 810 (2006) (in context of claim for prescriptive easement, land taken by BRA for urban renewal purposes held for "other public purpose," not conservation). Although as a practical matter, certain aspects of an urban renewal plan may accomplish goals similar to those outlined in art. 97, the overarching purpose for which the land is taken is distinct from art. 97 purposes.

With that distinction in mind, the issue is whether the project site can nonetheless be characterized as having been "taken or acquired for [art. 97] purposes." Reported cases interpreting art. 97 are scarce. In concluding that the project site was taken for art. 97 purposes, the motion judge relied heavily on the June 6, 1973, opinion of then Attorney General Robert Quinn. See Rep. A.G., Pub. Doc. No. 12, at 139 (1973) (Quinn Opinion). Using the Quinn Opinion for guidance, she identified certain aims or objectives referenced in the 1964 urban renewal plan, including the creation of public ways, parks, open space, and plazas, and a means of utilizing and enjoying the harbor. Because those aims were consistent with the purposes of art. 97, the judge concluded that the project site, which realizes them, was taken for art. 97 purposes and is therefore subject to the two-thirds vote requirement. Not surprisingly, the plaintiffs rely extensively on the Quinn Opinion in their arguments before this court.

The Quinn Opinion was issued in response to a general inquiry from the Speaker of the House of Representatives regarding the applicability of art. 97, and was rendered without reference to any particular set of facts. Although the Quinn Opinion is entitled to careful judicial consideration on the question of the scope of art. 97 and the intent of its drafters, see Opinions of the Justices, 383 Mass. 895, 918 (1981), citing Rep. A.G., Pub. Doc. No. 12, at 141 (concluding art. 97 applies retroactively), its interpretation of art. 97 is not binding in its particulars, and we are hesitant to afford it too much weight due to the generalized nature of the inquiry and the hypothetical nature of the response.13 See A.J. Cella, Administrative Law and Practice § 20, at 70-75 (1986) (discussing legal effect of opinions of the Attorney General).

The Quinn Opinion suggests a more expansive reading of art. 97 than we afford it today, and it may reasonably be read to support the plaintiffs' argument that the project site is subject to art. 97. We disagree with the Quinn Opinion to the extent it suggests that the vast majority of land taken for any public purpose may become subject to art. 97 if the taking or use even incidentally promotes the "conservation, development and utilization of the ... forest, water and air," Rep. A.G., Pub. Doc. No. 12, at 142, or that the land simply displays some attributes of art. 97 land generally.14 Id. at 143. We also do not agree that the relatively imprecise language of art. 97 warrants an interpretation as broad as the Quinn Opinion would afford it, particularly in light of the practical consequences that would result from such an expansive application, as well as the ability of a narrower interpretation to serve adequately the stated goals of art. 97.

The critical question to be answered is not whether the use of the land incidentally serves purposes consistent with art. 97, or whether the land displays some attributes of art. 97 land, but whether the land was taken for those purposes, or subsequent to the taking was designated for those purposes in a manner sufficient to invoke the protection of art. 97. See Selectmen of Hanson v. Lindsay, 444 Mass. 502, 508-509 (2005) (art. 97 protections may arise where subsequent to taking for purposes other than art. 97, land is "specifically designated" for art. 97 purpose by deed or other recorded restriction). See also Toro v. Mayor of Revere, 9 Mass.App.Ct. 871, 872 (1980) (applicability of art. 97 hinged on whether land had in fact been conveyed "to the conservation commission ... to maintain and preserve it for the use of the public for conservation purposes"). In this case, while it can be argued that the project site displays some of the attributes of a park15 and serves the purpose of the utilization of natural resources — in that it promotes access to the waterfront and the sea — this specific use is incidental to the overarching purpose of urban renewal for which the land including the project site was originally taken. Cf. Benevolent & Protective Order of Elks, Lodge No. 65 v. Planning Bd. of Lawrence, 403 Mass. 531, 551-552 (1988), citing Papadinis v. Somerville, 331 Mass. 627, 632 (1954) (any benefit from disposition to private redeveloper of land taken for urban renewal purposes is "incidental to the main purpose of the plan, which is the elimination of a substandard, decadent, or blighted open area").

In Selectmen of Hanson v. Lindsay, supra, we held that a town meeting vote to designate for conservation purposes land that had originally been taken for tax purposes did not subject that land to art. 97 protections absent recordation of a restriction on the title. Without the execution or recordation of a deed containing the conservation restriction, the land "never became specifically designated for conservation purposes in the first instance" and accordingly "was not held for a specific purpose" under art. 97, so "compliance with the provisions of art. 97... was not required." Id. at 508-509. This was true despite the clear intent of the town meeting members to hold the property for conservation purposes. Id. at 505. As the plain language of art. 97 indicates, for land to be subject to the two-thirds vote requirement on disposition or use for other purposes, it must be "taken or acquired for [the] purpose" of protecting interests covered by art. 97. In Selectmen of Hanson v. Lindsay, supra at 508-509, where the property had indisputably been acquired as a tax forfeiture and held as general corporate property, the town had to deed the land to itself for conservation purposes — or record an equivalent restriction on the deed — in order for art. 97 to apply to subsequent dispositions or use for other purposes. Here, where the land at issue is but a small part of a much larger taking effectuated for the purposes of urban renewal, it is difficult to identify a "specific purpose" for which the project site was acquired or held that would clearly bring it within the protection of art. 97.16 See id. at 509.

Because the spirit of art. 97 is derived from the related doctrine of "prior public use," cases applying that doctrine inform our analysis. See Rep. A.G., Pub. Doc. No. 12, at 146 (prior public use doctrine "background against which [art. 97] was approved"). See also Rep. A.G., Pub. Doc. No. 14, 131 (1980) ("language of Article 97 must be read in conjunction with the judicially developed doctrine of `prior public use'"). The prior public use doctrine holds that "public lands devoted to one public use cannot be diverted to another inconsistent public use without plain and explicit legislation authorizing the diversion." Robbins v. Department of Pub. Works, 355 Mass. 328, 330 (1969). See Brookline v. Metropolitan Dist. Comm'n, 357 Mass. 435, 440 (1970), and cases cited. However, that doctrine is only applicable "to those lands which are in fact `devoted to one public use'" (emphasis added). Muir v. Leominster, 2 Mass.App.Ct. 587, 591 (1974), quoting Robbins v. Department of Pub. Works, supra. In the Muir case, the Appeals Court held the prior public use doctrine inapplicable to the sale for commercial purposes of a parcel of land, where that parcel had been conveyed to a city as a gift with no limitation on its use but was in fact used for thirty years as a playground and for other recreational purposes. Muir v. Leominster, supra at 588-589, 591 ("[I]n this case there had been neither prior legislative authorization of a taking for a particular purpose nor a prior public or private grant restricted to a particular purpose").

Here, as the motion judge highlighted, the 1964 urban renewal plan enumerates, among its listed planning and design objectives, certain objectives that are consistent with art. 97 purposes. The 1964 urban renewal plan also contains vague descriptions of the project site and Long Wharf generally that are consistent with its current use as an open space.17 Most significantly, § 202 of the 1964 urban renewal plan, entitled "Planning Objectives," states as one of its fifteen objectives, the objective "[t]o provide public ways, parks and plazas which encourage the pedestrian to enjoy the harbor and its activities." In addition, in § 203, entitled "General Design Principles," the plan lists several design principles, including:

By definition, G. L. c. 121B vests in the BRA the authority to take or acquire "decadent, substandard or blighted open area[s]" for the purpose of eliminating those undesirable conditions (emphasis added). See G. L. c. 121B §§ 11, 45, 47. However, it does not follow that, where a comprehensive urban renewal plan calls for some areas of a taking to be left open — without a more specific and particularized invocation of art. 97 purposes unique to those areas that effectively designates those areas as separate and apart from the rest of the taking — a two-thirds vote of the Legislature is required for any subsequent change in use or disposition of those open areas. Nor do we find sufficient to invoke art. 97 protection the fact that a comprehensive urban renewal plan may identify, among other objectives, some objectives that are consistent with art. 97 purposes, or where certain areas taken pursuant to that plan ultimately display some attributes of art. 97 land. A contrary rule would be particularly nonsensical where the proposed change in use or disposition that would purportedly trigger the two-thirds vote is made in furtherance of the goals of the particular urban renewal plan and is otherwise appropriate.

Given the overarching purpose of the 1964 urban renewal plan to eliminate urban blight through the comprehensive redevelopment of the waterfront area, including its revitalization through the development of mixed uses and amenities, it cannot be said that the retention of certain open spaces, like the project site, is sufficiently indicative of an art. 97 purpose as to trigger a two-thirds vote of the Legislature should the BRA wish to slightly revise the use of certain spaces in a manner consistent with the objectives of the original urban renewal plan.18 The fact that the 1964 Urban Renewal Plan (which covered a large section of downtown Boston) provided in general terms for open spaces and pedestrian access to the water's edge is itself insufficient to invoke art. 97 protections for parts of the original taking that ultimately serve those general purposes. The single, fleeting reference in the 1964 urban renewal plan to an "observation platform" on Long Wharf similarly fails to adequately invoke the specific purposes of art. 97.

Nevertheless, we disagree with the BRA's contention that it cannot possibly take land for art. 97 purposes pursuant to its urban renewal powers under G. L. c. 121B. The purposes served by urban renewal and by art. 97 are not mutually exclusive. Certainly, for the BRA to take land by eminent domain, it must exist in a "decadent, substandard, or blighted" condition. However, where an urban renewal plan accompanying a taking clearly demonstrates a specific intent to reserve particular, well-defined areas of that taking for art. 97 purposes, the BRA conceivably may take land for such purposes while remaining within its statutory authority.19 The recording of a restriction on the use of land subsequent to a taking may also place land within the protections of art. 97. See Selectmen of Hanson v. Lindsay, 444 Mass. 502, 504-506 (2005). Furthermore, we disagree with the BRA that the language of an order of taking is necessarily determinative of the applicability of art 97. Under certain circumstances not present here, the ultimate use to which the land is put may provide the best evidence of the purposes of the taking, notwithstanding the language of the original order of taking or accompanying urban renewal plan. See Quinn Opinion, supra at 142-143.

b. Occurrence of triggering condition. Even if art. 97 did apply to the project site, the issue would remain whether the department's issuance of the chapter 91 license constituted a disposition or change in use of the land triggering the two-thirds vote requirement. Although not necessary to our holding, we briefly address the issue.

The answer to this question depends on whether the chapter 91 license is in fact a mere license, or if it is more properly characterized as an easement. Although the granting of an easement over art. 97 land constitutes a disposition triggering the two-thirds vote requirement, a disposition of any lesser property interest does not. See Opinions of the Justices, 383 Mass. 895, 919 (1981) (relinquishment by Commonwealth of any vestigial property interests in tidelands other than "lands and easements" would not trigger art. 97 voting requirement); Miller v. Commissioner of the Dep't of Envtl. Mgt., 23 Mass.App.Ct. 968, 969-970 (1987) (department's issuance of revocable one-year permit to operate ski area did not trigger two-thirds vote under art. 97).

General Laws c. 91, § 15, states that "the grant of a license" under that chapter "shall not convey a property right."20 The BRA owns the project site, and accordingly, the BRA's right to lease the Long Wharf Pavilion to a restaurant operator derives not from the chapter 91 license, but from the fact that the BRA owns the land. The chapter 91 license merely certifies that the planned use, including the lease, complies with G. L. c. 91 and accompanying department regulations. It does not, as the motion judge concluded, transfer from the department to the BRA "an extent of legal control over the land at issue."21 Any disposition triggering the art. 97 voting requirement would need to be granted by the BRA — as would be the case with the lease to the restaurant operator — not to the BRA.

The chapter 91 license itself is "granted upon the express condition that any and all other applicable authorizations ... shall be secured by the Licensee prior to the commencement of any activity or use authorized pursuant to this License" (emphasis in original). The license also states that it is "granted subject to all applicable Federal, State, County, and Municipal laws, ordinances and regulations." Even if, arguendo, the chapter 91 license created a property right, the right it created is a contingent future interest and would not trigger the voting requirement until the interest vests on obtaining all necessary approvals.

Nor does the issuance of the chapter 91 license constitute a "use[] for other purposes" that would trigger the legislative vote. For lands to which art. 97 does apply, art. 97 legislative approval is likely just one of the many approvals a project proponent will need to acquire in order to proceed with the project. These approvals are issued by various State and local regulatory agencies and are largely independent of one another, yet all are necessary to proceed with the project. It would make little practical sense to condition the application for one such approval, in this case the chapter 91 license, on the successful application for another approval. The chapter 91 license facilitates the change in use in the same way the zoning variances and other necessary approvals do. A project proponent like the BRA could conceivably obtain the necessary approvals to change the use of land and, for myriad reasons, never follow through on the planned use. Article 97 requires a two-thirds vote of the Legislature prior to an actual change in use, not mere preparations for that change.

3. Conclusion. For the reasons discussed, we conclude that art. 97 does not apply to the project site and therefore, a two-thirds vote of the Legislature is not required to approve the planned redevelopment. Because the motion judge did not review the issuance of the chapter 91 license pursuant to G. L. c. 30A, § 14, we remand the case to the Superior Court for proceedings consistent with this opinion.22

So ordered.