1. Of the judgment of the court of first instance, the part against the defendant is revoked, and all the plaintiffs' claims corresponding to the revoked part are asserted.

1. The court's explanation on this part of the basic facts is identical to the corresponding part of the reasoning of the judgment of the first instance (from the third to the fifth to the nineth class), and thus, this part is cited in accordance with the main sentence of Article 420 of the Civil Procedure Act.

2. The parties' assertion

A. The defendant, while managing the reservoir of this case, obtained profits equivalent to the rent of the land of this case without any legal grounds by occupying and using the land of this case, which is incorporated into the site, and thereby suffered losses equivalent to the same amount from the plaintiffs, who are the owners of the land of this case. Thus, the defendant is obligated to return unjust enrichment equivalent to the rent of this case to the plaintiffs.

B. G, the former owner of the instant land, gave up the right to use and benefit from the instant land while providing the instant land as a site for the instant reservoir, and the Plaintiffs acquired it with the knowledge that the use and benefit from the instant land is restricted during the instant auction procedure. As such, even if the Defendant occupied and used the instant land, it cannot be said that the Plaintiffs suffered damage therefrom.

Therefore, the defendant does not bear the obligation to return unjust enrichment to the plaintiffs.

3. Determination

A. In a case where a landowner provided the land owned by him for public use, such as a road and a site laid underground, the relevant legal doctrine comprehensively examines the following: (a) details and period of ownership of the land; (b) the details and scale of the owner’s provision of the land for public use; (c) the existence of the owner’s interest or benefits from the provision of the land; (d) the location or form of the relevant part of the land; (e) the relationship with the neighboring land and surrounding environment; and (e) the comparative balancing between the landowner’s ownership guarantee and the public interest, if the owner may be deemed to have waived exclusive, exclusive, and exclusive rights