JOINT FILING AGREEMENT

EXHIBIT A

JOINT FILING AGREEMENT

We, the undersigned, hereby express our agreement that the attached Schedule 13D is, and any further amendments thereto signed by each of the undersigned shall be, filed on behalf of each of us pursuant to and in accordance with the provisions of Rule 13d-1(k) under the Securities Exchange Act of 1934, as amended. This agreement may be terminated with respect to the obligations to jointly file future amendments to such statement on Schedule 13D as to any of the undersigned upon such person giving written notice thereof to each of the other persons signatory hereto, at the principal office thereof.

Date: February 27, 2017				COLUMBIA PIPELINE GROUP, INC.
				By:		/s/ Xxxxxxxxx X. Xxxxx
				Name:		Xxxxxxxxx X. Xxxxx
				Title:		Controller and Principal Financial Officer
				By:		/s/ Xxx X. Xxxxxx
				Name:		Xxx X. Xxxxxx
				Title:		Corporate Secretary
				TRANSCANADA PIPELINE USA LTD.
				By:		/s/ Xxxxxxxxx X. Xxxxx
				Name:		Xxxxxxxxx X. Xxxxx
				Title:		Vice-President
				By:		/s/ Xxx X. Xxxxxx
				Name:		Xxx X. Xxxxxx
				Title:		Corporate Secretary
				TRANSCANADA PIPELINES LIMITED
				By:		/s/ Xxxxxxxxx X. Xxxxxxxx
				Name:		Xxxxxxxxx X. Xxxxxxxx
				Title:		Vice-President, Law and Corporate Secretary
				By:		/s/ Xxxx X. Xxxxxx
				Name:		Xxxx X. Xxxxxx
				Title:		Vice-President, Finance and Treasurer
				TRANSCANADA CORPORATION
				By:		/s/ Xxxxxxxxx X. Xxxxxxxx
				Name:		Xxxxxxxxx X. Xxxxxxxx
				Title:		Vice-President, Law and Corporate Secretary

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				By:		/s/ Xxxx X. Xxxxxx
				Name:		Xxxx X. Xxxxxx
				Title:		Vice-President, Finance and Treasurer

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