There have been differing interpretations as to whether an Alteration Permit expires and must be extended during an on-going alteration project.  In 4VAC50-20-80, Alterations Permits, Paragraph F, states: “The Alteration Permit shall be valid for the construction sequence with milestones specified in the approved Alteration Permit Application.”  However, Paragraph G and issued Dam Safety Alteration Permits refer to a specific timeframe in which the work must commence.  One interpretation has been that as long as construction work has commenced within the timeframe specified in the issued Alteration Permit, then construction may continue after the specified timeframe has passed, and there is no action required by the owner, engineer, or Regional Engineer.  A different interpretation has been that the timeframe assigned in the Alteration Permit is based on the construction sequence and milestones specified in the Alteration Permit Application, and if the actual construction schedule extends beyond the Alteration Permit timeframe, then a new Alteration Permit should be issued to extend the permit timeframe.  Since alteration of an impounding structure is a significant activity that presents risks to the public and infrastructure, the State should consider requiring that an Alteration Permit be effective throughout the duration of construction and completion of all closeout activities specified in 4VAC50-20-80.  The State should require the impounding structure owner to submit a letter describing the changes to the construction sequence and milestones that necessitate an Alteration Permit extension in order to request a new Alteration Permit.  This request would not require any fees or significant effort, and the extended Alteration Permit would provide reassurance to the public, owner, and contractor that the State has approved of the on-going work at the impounding structure.