The plaintiffs, owners of waterfront property in Falmouth (town), filed a notice of intent and an application for a variance with the town’s conservation commission (commission) seeking permission to construct a timber pier, ramp, and floating dock. The commission issued its decision denying the application one day late. The plaintiffs appealed the decision to the Superior Court and sought a superseding order of conditions from the Department of Environmental Protection (DEP). During the course of the proceedings before the DEP, the plaintiffs’ *486plan was revised, and the parties filed a joint motion to stay the Superior Court action in order to seek review of the revised plan by the commission. Although the DEP issued a superseding order of conditions based on the revised plan, the plaintiffs continued to pursue consideration of their revised plan by the commission, resulting in a second decision of denial that was issued timely. Subsequently, a Superior Court judge upheld the commission’s second decision of denial.2 The plaintiffs appealed. In this appeal, we are asked to determine whether the plaintiffs may ignore the commission’s second decision and rely, instead, on the superseding order of conditions previously issued by the DEP. See Oyster Creek Preservation, Inc. v. Conservation Commn. of Harwich, 449 Mass. 859, 863 (2007). We conclude that in the circumstances of this case, the DEP’s superseding order of conditions controls.
Background. On February 10, 2006, the plaintiffs, Thomas Regan and Donna Friedman, filed a notice of intent with the commission seeking an order of conditions allowing them to construct a timber pier, ramp, and floating dock on their property abutting Green Pond in East Falmouth. Because the density of shellfish in the area exceeded the density allowed by § 10.16(l)(h)(2)3 of the Falmouth wetland regulations (FWR) applicable to coastal docks and piers, they also applied for a variance pursuant to FWR § 10.13.4 The commission held public *487hearings on March 1, 2006, and May 17, 2006. The public hearing was closed on May 17, 2006. On June 7, 2006, the commission publicly voted to deny the permit and variance, and on June 8, 2006, issued a written decision of denial (first decision) and mailed it to the plaintiffs.
Thereafter, the plaintiffs sought a superseding order of conditions from the DEP.5 On July 28, 2006, the plaintiffs also commenced an action in Superior Court seeking certiorari review of the commission’s first decision claiming, among other things, that the decision was in excess of the commission’s authority and jurisdiction; made upon unlawful procedure; and arbitrary, capricious, and an abuse of discretion.
During the course of proceedings before the DEP, the plaintiffs redesigned their plan. Desiring to present the new plan to the commission with the hopes of winning its approval, the plaintiffs and the commission reached a joint agreement in the certiorari case to request a remand to the commission for consideration of the revised plan, but agreed that the Superior Court would retain jurisdiction over the case. They filed a joint motion for remand on December 13, 2006, and on December 18, 2006, a Superior Court judge entered an order remanding to the commission but retaining jurisdiction.6
On January 3, 2007, the DEP notified the parties of its conclusion that the project, as revised and conditioned, adequately protects the interests of the Wetlands Protection Act (act), G. L. c. 131, § 40, and issued a corresponding superseding order of conditions permitting construction of the pier, ramp, and floating dock. Nonetheless, on February 7, 2007, the plaintiffs filed a document with the commission explaining the revisions it had *488made to the plan and essentially asking the commission to reconsider its first decision denying the permit and variance. On February 28, 2007, the commission held a public hearing to review the revised plan. After discussion, which filled two and one-half single-spaced pages of transcript, the commission voted to “close and take it under advisement leaving it open for one week for submission” of a case cited by the plaintiffs. The plaintiffs, through counsel, supplemented the record with four cases and a synopsis of each by letter dated March 5, 2007. At a commission hearing on March 14, 2007, it was established that the record had been supplemented and then, without further discussion, one of the members read proposed findings. Thereafter, the commission voted to adopt the findings and deny first the variance and then the notice of intent. On March 15, 2007, the commission mailed its written decision of the denials (second decision) to the plaintiffs, but admittedly failed to include the four-page attachment, including the findings of fact. The second decision incorporated the record from the preremand hearings.
On June 25, 2007, a Superior Court judge allowed the parties’ joint motion to return the case to the docket and to supplement the record with the administrative record from the remand proceedings. On October 23, 2007, the Supreme Judicial Court issued Oyster Creek Preservation, Inc. v. Conservation Commn. of Harwich, which clarified that when a conservation commission issues its decision after the statutory deadline, it loses “the right to insist on the provision of its local bylaw, and . . . any superseding order issued by the DEP should apply in its stead.” Id. at 866. On April 4, 2008, the parties filed cross motions for judgment on the pleadings. The plaintiffs argued that the commission’s first decision was untimely and the DEP’s superseding order of conditions should apply.7 Alternatively, the plaintiffs argued that the commission’s second decision fails to satisfy the requirements of certiorari review in that it did not result from proper deliberation, constituted an abuse of discretion, was unsupported by substantial evidence, and was the result of the commission’s failure to apply the proper standard of review. In *489response, the commission argued that its second decision should be upheld. The judge denied the plaintiffs’ motion and allowed the commission’s cross motion for judgment on the pleadings.
Discussion. Generally, “[a] local authority has final determination regarding project applications when it acts pursuant to an ordinance or by-law which provides more stringent requirements than those provided by the act.” Healer v. Department of Envtl. Protection, 73 Mass. App. Ct. 714, 718 (2009). Thus, when a local conservation commission bases its decision on a by-law that provides greater protection than the act, the decision generally is not preempted by a superseding order of conditions issued by the DEP under the act. Ibid. See Dubuque v. Conservation Commn. of Barnstable, 58 Mass. App. Ct. 824, 826 n.4 (2003), citing Lovequist v. Conservation Commn. of Dennis, 379 Mass. 7 (1979); Fafard v. Conservation Commn. of Barnstable, 432 Mass. 194 (2000). A local authority, however, may lose the right to insist on the provisions of its local bylaw if, for example, it fails to comply with the timing provisions contained in the act. See Oyster Creek Preservation, Inc., 449 Mass. at 866 (“timing provisions in the act are obligatory, and a local community is not free to expand or ignore them”). “[W]here a conservation commission issues its decision after the statutory deadline, it is appropriate that it should lose the right to insist on the provisions of its local bylaw, and that any superseding order issued by the DEP should apply in its stead.” Id.
The act mandates that a conservation commission issue an order within twenty-one days of the close of the public hearing. Id. at 863, quoting from G. L. c. 131, § 40. The date an order “issues” is the date it is mailed. Oyster Creek Preservation, Inc. at 864. It is undisputed that the commission issued its first decision on the twenty-second day, and in the ordinary course, at least after Oyster Creek Preservation, Inc. was issued, the DEP’s superseding order would control without further resort to the commission.
Here, in upholding the second decision, the Superior Court judge concluded that the DEP’s superseding order does not usurp the local authority because the plaintiffs waived any procedural issue related to the first decision by failing to object to that late decision before the commission, and by further *490invoking the jurisdiction of the commission by agreeing to remand the case to the commission for review of their revised plan. We conclude otherwise.
The plaintiffs took these actions, however, at a time prior to the decision in Oyster Creek Preservation, Inc. At the time, not anticipating the impact of Oyster Creek Preservation, Inc., the plaintiffs’ course of action was entirely reasonable and, in the circumstances, cannot be viewed as any kind of waiver. Indeed, for plaintiffs’ counsel to have done otherwise might well be seen as professionally questionable since, until Oyster Creek Preservation, Inc., the commission’s approval presumably remained necessary.
In short, the instant circumstances are controlled in material respects by the reasoning of Oyster Creek Preservation, Inc. Plaintiffs’ counsel’s practice of prudent lawyering should not cause his clients to lose that to which they are procedurally, substantively, and statutorily entitled.8
The judgment is vacated and a new judgment shall enter approving the superseding order of conditions issued by the DEP on January 3, 2007.
So ordered.
We note that the judgment dated December 17, 2008, appears to contain a clerical error in that it states that the commission’s June 8, 2006, decision is being upheld. According to the judge’s memorandum of decision and order, it is clear that the judge’s intent was to uphold the commission’s second decision dated March 14, 2007.
Section 10.16(l)(h)(2) of the FWR prohibits construction of a new dock or pier where there are significant quantities of shellfish essentially within thirty-five feet of the proposed mooring field and the area historically has been used for shellfishing or has the potential to be used for shellfishing.
Section 10.13(1) of the FWR provides that “[a]ny individual who suffers a Hardship as defined in these regulations may petition for a variance from Chapter 235 and these regulations provided: (a) The project does not meet one or more of the performance standards articulated in FWR 10.16 through 10.60; and (b) Mitigation measures are proposed by the Applicant that will allow the project to be conditioned so as to contribute to the protection of the Resource areas identified in Chapter 235; and (c) The project will not create a nuisance; and (d) The hardship was not created by the applicant or the applicant’s agents; and (e) The resource areas delineated in Chapter 235 will be better protected if the project is allowed than if the project is denied, or the project has an overriding public benefit.”
The record does not establish the date the plaintiffs sought review by the DEP, but there is no assertion that it was untimely.
The assented to motion requested that the court remand “for further proceedings, findings, and action while retaining jurisdiction over the matter.” The motion provided that the plaintiffs within thirty days of the order would file with the commission a revised plan and application and that the commission would schedule a public hearing within twenty-one days and issue a written decision “including all of its findings, standard conditions, and special conditions, if any,” within twenty-one days of the close of the public hearing or record. Thereafter, the court record would be supplemented with the administrative record of the remand proceedings. “The case shall then be processed and heard in compliance with [the court’s] Standing Order 1-96.”
Neither the plaintiffs’ motion for judgment on the pleadings nor the commission’s cross motion are in the record. Our recitation of their content is derived from the judge’s memorandum of decision and order.
Deciding as we do, we have no need to address the plaintiffs’ other arguments.