Plaunt v Renfrew Power Generation Inc., 2017 ONSC 1868
HEARD: January 18, 2017
REASONS FOR DECISION ON DECERTIFICATION MOTION
R. SMITH J.
 The Defendant, Renfrew Power Generation Inc. (“RPG”) has brought a motion to decertify this class action on the ground that the surveyor’s evidence, obtained after certification was granted, discloses that the class members’ claims for trespass do not raise common issues. As a result RPG submits that a class proceeding is no longer the preferable procedure.
 Between 1911 and 1917, Ontario Hydro (“the predecessor to RPG”) built a dam at the outlet of Round Lake and acquired licences of occupation to raise the level of Round Lake to 107.5 feet above sea level, for parts of the shoreline of Round Lake. This is referred to as the “107.5 Contour Line.”
 The class consists of approximately 400 cottage owners who own property surrounding Round Lake. The Plaintiffs allege that their shoreline has been eroded because RPG or its predecessors raised level of the water in Round Lake and as a result, they allege that RPG is trespassing on their land, by storing water on their property.
 The Plaintiffs argued at the original certification motion that the 107.5 Contour Line was created in 1917 and established a fixed dividing line between public and private lands. They argued that any encroachment of water past this theoretical 107.5 Contour Line constituted trespass by RPG.
 Very little, if any, evidence of deeds of land or surveys showing the boundary of class members’ lands was presented at the original certification motion. Some evidence was provided of a “Boswell” survey prepared in 1917 that allegedly established the 107.5 Contour Line around Round Lake. As a result, I understood that all of the class members’ properties were affected by the 107.5 Contour Line, and that it was a reference point for each class members’ property boundary line. I reasoned that a determination of whether the 107.5 Contour Line did or did not create a boundary line between public lands and private lands, or was only a flooding easement, would have affected all class members and would have moved their action for trespass forward in a substantial manner..
New Survey Evidence
 After the certification decision, the parties retained surveyors to obtain evidence of the legal descriptions and boundaries of the cottage owners’ lands surrounding Round Lake and to prepare expert reports. The Plaintiffs obtained a report from Mr. Stewart. RPG obtained a report from Mr. deRijcke in which he stated that not all of the class members’ lands surrounding Round Lake were affected by the 107.5 Contour Line because his report states that some of the lands surrounding the lake were acquired by the Hydro Electric Power Commission of Ontario (“HEPC”) through Crown grants where the legal boundaries of such grants were based on metes and bounds descriptions without any reference to 107.5 Contour Line. For a number of lots abutting the lake, HEPC was not required to obtain flooding rights because if the water level was raised to 107.5 feet, would not exceed the inner limit of the 66 foot road allowance around Round Lake. No evidence was provided at the original certification motion that there was a 66’ unopened road allowance completely surrounding Round Lake which has existed since it was surveyed in the 1860’s. The cottage owners’ boundary line did not include the unopened road allowance unless it was subsequently surveyed and closed by the Township.
 The deRijcke report also identified many categories of class members’ properties, whose boundaries were not defined by any reference to the 107.5 Contour Line. His evidence in this respect was not disputed by the plaintiff’s surveyor, Mr. Stewart.
Test for Decertification
 Section 10(1) of the Class Proceedings Act, 1992, S.O. 1992, c. 6 - Ontario.ca (“CPA”) states that a court may decertify a class proceeding where the conditions for certifying a class action under s. 5(1) of the CPA no longer apply.
 In Pearson v. Inco Ltd., 2009 CarswellOnt 1000 (Ont. Sup. Ct.), the Court held that it had the authority to reopen and reconsider the question of whether the requirements for certification were still satisfied in light of new evidence, subsequent facts, or developments. In this case, I am satisfied that there is new survey evidence demonstrating that the property boundaries for many of the class members are not determined by reference to the 107.5 Contour Line, that a 66 foot unopened road allowance existed around Round Lake prior to the water level being raised, and the evidence that HEPC acquired the right to flood the lands by a number of different methods including obtaining title by Crown grants using metes and bounds descriptions, by grants from private land owners, by grants of easements, as well as through several licences of occupation granting it the right to flood the lands up to the 107.5 level.
 I find that there is new evidence and additional facts relating to the boundaries of the cottagers’ property lines around Round Lake as set out by both parties’ surveyors in their expert reports, which I will consider to decide whether the conditions for certification of a class proceeding still apply.
Is there a Common Issue for all Class Members
 In Hallick v. Toronto (City of), the Supreme Court held that for an issue to be “common” it must be necessary to the resolution of each class members’ claim and form a substantial ingredient of each class members’ claim.
 The new evidence demonstrates that many of the current class members do not have a legal boundary that is defined by any reference to the 107.5 Contour Line. The deRijcke report shows that many class members have acquired title to their land with boundaries established by metes and bounds descriptions or alternatively, by plans of survey and not by reference to the 107.5 Contour Line.
 In addition, RPG acquired the right to flood the lands around Round Lake to the 107.5 foot level through a number of different methods. The licences of occupation only affect a portion of the shoreline of Round Lake and do not affect all class members.
 In certifying the action initially, I was operating on the understanding that the 107.5 Contour Line was alleged to define the property line between public and private lands for all class members. The new evidence shows that this is not the case. The survey reports of both parties confirm that the HEPC acquired property in fee simple using metes and bounds descriptions for 50 separate properties without reference to the 107.5 Contour Line. Also, HEPC did not acquire flooding rights for 10 of the original township lots (200 acre parcels of land) where the flooding did not exceed the limit of the 66 foot road allowance, and for approximately 100 properties, the 107.5 Contour falls within the inner limits of the road allowance around Round Lake. In all of these cases, the 107.5 Contour Line would have no effect on the Plaintiffs’ claims for trespass.
 The Plaintiffs’ are unable to determine which class members have property boundaries that are defined by reference to the 107.5 Contour Line.
 Many class members, as currently defined, do not have a property boundary that is defined by any reference to the 107.5 Contour. As such, a resolution of the common issue does not form a substantial ingredient and it is not necessary to decide the certified common issue which is whether RPG is trespassing by storing water on their land as a result of erosion of the shoreline due to raising the level of Round Lake.
 Each cottage owner will have to obtain evidence from a surveyor to determine if any erosion has occurred which has affected their property line such that RPG is currently storing water on their land. A determination of whether the 107.5 Contour Line created a private/public property boundary or was only a horizontal flooding easement is not a relevant issue to a large number of the class members, because their property line is not defined by reference to the 107.5 Contour Line.
 In response, the Plaintiffs submit that, at para. 41 of the Vivendi decision of the Supreme Court, states that while a resolution of the common issue must be necessary to every class members’ claim, it did not require that each class member to be identically situated vis-à-vis the opposing party, or that the common issue predominates over the non-common issues to be determined for of each class members’ claim. However, in Vivendi, the Supreme Court also held that the class members’ claims must share a substantial common ingredient. In this case, whether the 107.5 Contour Line creates a public/private boundary is not necessary to determine if a trespass has occurred for a large number of the class members’ claims, nor is it a substantial common ingredient for all class members as currently defined.
 The Plaintiffs also argue that the Defendant should be estopped from bringing a decertification motion because the Defendant could have presented this survey evidence at the original certification motion. The plaintiffs also submit that RPG should not be allowed to bring a disguised late appeal of the certification decision. I am satisfied that there is sufficient new evidence which relates to the legal boundaries of many class members properties which demonstrates that the 107.5 Contour Line is not relevant to determining the boundaries of their land. I also find that the common issue as certified arose out of the plaintiffs’ submissions at the certification motion and it was not reasonable for the Defendant to have produced evidence directly related to this common issue before the original certification motion. As a result, I conclude that RPG should not be estopped from bringing this decertification motion for either of the above reasons.
 The common issue as certified is not a necessary and a substantial ingredient of each class members’ claim. Each individual class member will have to have a surveyor determine their legal property boundary line facing Round Lake and then determine if their shoreline has been eroded to such an extent that part of their land is now covered by water. The surveyor will have to determine if the water level, as raised in 1917, plus any erosion that has occurred over the past 100 years, now covers part of their property.
 The issue that the Plaintiffs are trying to raise is whether RPG is responsible in trespass for raising the water level of Round Lake, which has caused erosion to occur such that water is mow stored on some owners’ lands. However, to decide this issue will require evidence for each individual cottage owner to determine the legal boundaries of the property they purchased, and to determine whether water covers part of their property
 I agree with RPG’s submissions that common issue as certified for the class as presently defined does not meet the criteria of s. 5(1) of the CPAbecause the common issue is not a necessary or a substantial ingredient of each class members’ claim, as many class members’ property boundary is not related to the 1917 Contour Line.
 The Plaintiffs shall have 15 days to make further submissions. The Defendant shall have 15 days to respond and the Plaintiff 7 days to reply. A further oral hearing is a possibility depending on the submissions.
 The Defendant shall make submissions on costs within 15 days, the Plaintiffs shall have 15 days to respond and the Defendant shall have 7 days to reply.
Mr. Justice Robert Smith
Released: March 23, 2016