Section 20. (a) As used in this section, the following words shall, unless the context clearly indicates otherwise, have the following meanings:—

''Public agencies'', any city, town, county, district, or other political subdivision, authority, public corporation, board or commission of the commonwealth; the commonwealth or any agency or department thereof; any such agency, department, political subdivision or entity in a state adjoining the commonwealth; any interstate agency; the United States government and any department or agency thereof.

''Purposes of this section'', the purposes set forth in clauses (1) to (24), inclusive, of section two, and any similar and compatible purposes related to the management, protection, and enhancement of natural resources and the environment.

''Region'', any geographically-described area within which the powers and duties provided in a joint powers agreement will be exercised.

''Joint powers agreement'', a document specifying the terms and conditions of the joint exercise of powers and duties entered into by participating public agencies pursuant to the laws governing any such agency, the provisions of this section, and such procedural regulations as the secretary of environmental affairs may promulgate.

(b) In order to facilitate intergovernmental action on natural resource and environmental issues and thereby to advance the objectives set forth in Article XCVII of the Articles of Amendment to the Constitution of the Commonwealth, any two or more public agencies, for any region they may elect, may apply to the secretary of environmental affairs to enter into an agreement for the joint exercise of certain of their powers and duties. The proposed joint powers agreement shall specify:

(1) the purpose and nature of the arrangement;

(2) the work to be performed, and the division or sharing of responsibility among public agencies;

(3) the estimated costs and the methods of financing;

(4) the method of administration; and

(5) the duration of the proposed agreement.

Following a public hearing in the specified region, and upon a written finding that the proposed agreement meets the requirements of this section, the secretary may approve the agreement. The secretary shall file a copy of such approval, with a copy of the agreement, with the clerks of the senate and the house of representatives and with the state secretary. Any proposed agreement not disapproved within forty-five days after said public hearing shall be deemed to have been approved. Agreements may be modified by the secretary and may be extended for additional terms, but in no event shall a joint powers agreement be in existence for more than five years without express statutory approval.

(c) A joint powers agreement established pursuant to the provisions of this section may be administered by a board comprised of at least one member representing each participating public agency. In order to enable a combination of public agencies to act together, the board shall coordinate the activities of such participating agencies, but only to the extent of the powers otherwise granted by law to one or more of the participating public agencies.

(d) Nothing in this section shall be construed to:

(1) amend, repeal or otherwise alter the authority or jurisdiction of, or establish, any public agency;

(2) confer any management authority over funds, land, or natural resources beyond the authority exercised by the participating agencies;

(3) authorize appropriated funds to be expended for the purposes of this section, or to be transferred or have the effect of being transferred from one appropriation account to another, except as otherwise authorized by law;

(4) amend, repeal or otherwise alter the authority of the department of environmental protection to undertake or order actions pursuant to chapter twenty-one E, nor otherwise to require said department to participate in a joint powers agreement if the commissioner thereof determines that such participation would conflict with the purposes of said chapter twenty-one E; nor

(5) create liability on the part of any public agency for the act or omission of another public agency.