Asset Retirement Obligations

9 Months Ended

Sep. 30, 2016

Asset Retirement Obligation Disclosure [Abstract]

Asset Retirement Obligations

Note 6. Asset Retirement Obligations

Asset retirement obligations (ARO) consist of estimated costs of dismantlement, removal, site reclamation and similar activities associated with our infrastructure assets. Changes in ARO are as follows:

(in thousands)	Nine Months Ended September 30,
	2016		2015
Asset Retirement Obligations, Beginning Balance	$	3,612	$	2,839
Liabilities Incurred	—		598
Revision of Estimate	1,224		—
Accretion Expense (1)	151		133
Asset Retirement Obligations, Ending Balance	$	4,987	$	3,570

⁽¹⁾  Accretion expense is included in depreciation and amortizationexpense in the consolidated statements ofoperations.

Revisions in 2016 were primarily due to changes in estimated costs for future abandonment activities of our gathering systems in the Wells Ranch and East Pony IDPs.

Liabilities incurred in 2015 were primarily due to our centralized gathering facility (CGF) in the Wells Ranch IDP.