Maintaining and Enhancing Hydroelectricity and River Restoration Act of 2022 This bill allows a new investment tax credit for 30% of the basis of any hydropower improvement property. The bill defines such property as property that, amount other things (1) adds or improves fish passage at a qualified dam (i.e., a hydroelectric dam licensed by the Federal Energy Regulatory Commission or legally operating without such a license before the enactment of this bill); (2) maintains or improves the quality of the water retained or released by such a dam; (3) promotes downstream sediment transport processes and habitat maintenance for such a dam; (4) removes an obsolete river obstruction; or (5) places into service an approved remote dam (i.e., a hydroelectric dam that services certain communities and does not contribute to atmosphere pollution).