Tidal wetland mitigation bank credits. Authorizes certain entities to purchase or use credits from a tidal wetland mitigation bank located in an adjacent river watershed when such bank contains the same plant community type and salinity regime as the impacted wetlands, which shall be the preferred form of compensation. The provisions of the bill apply only to tidal wetland mitigation banks with a polyhaline salinity regime located in certain subbasins when a tidal wetland mitigation bank with the same plant community type and salinity regime as the impacted wetlands is not available in the same river watershed as the impacted wetland.