The commission shall approve, in whole or in part, the application and issue an amendment based on a water supply contract only if it determines that:(1) the supplier has met the requirements of §§297.101-297.108 of this title (relating to Water Supply Contracts and Amendments);(2) the proposed contractual amendment is not detrimental to the public welfare, including a consideration of whether the contract, together with all other contracts previously submitted by the supplier and contractual permits in effect at the time the commission considers the application, provides for the storage, diversion, or use of state water in excess of the water right of the supplier; and(3) the proposed sale will not impair existing water rights.