Because the quality of the waters of this State is vital to the public and private interests of its citizens and because pollution constitutes a menace to public health and welfare, creates public nuisances, is harmful to wildlife, fish and aquatic life, and impairs domestic, agricultural, industrial, recreational, and other legitimate beneficial uses of water, and the problem of water pollution in this State is closely related to the problem of water pollution in adjoining states, it is State public policy to improve, conserve, and manage the quality of the waters of the State and protect, maintain, and improve the quality of water for public supplies, propagation of wildlife, fish and aquatic life, and domestic, agricultural, industrial, recreational, and other legitimate beneficial uses. Also, it is State public policy to provide that no waste is discharged into any waters of this State without first receiving necessary treatment or other corrective action to protect the legitimate beneficial uses of this State's waters, and to provide and promote, through innovative and alternative methods of waste and wastewater treatment, prevention, abatement, and control of new or existing water pollution. The Department shall cooperate with the agencies of other states and the federal government in carrying out these objectives.