Chapters 51-68 of this title do not repeal or affect the right or power of eminent domain under other existing laws, and any corporation which shall have the power of eminent domain under existing laws shall have the power to the same extent and in the same manner as if organized under chapters 51-68 of this title, and all statutes of this state granting the power of eminent domain and making compensation shall remain in force and effect and applicable to the appropriate existing corporations and to the appropriate corporations organized under chapters 51-68 of this title.