(a) The Self-Governance Tribe and the Secretary should work together during the initial stages of project development to identify program and project related costs associated with carrying out environmental responsibilities for proposed projects. The goal in this process is to identify the costs associated with all foreseeable environmental review activities.

(b) If unforeseen environmental review and compliance costs are identified during the performance of the construction project, the Self-Governance Tribe or, at the request of the Self-Governance Tribe, the Self-Governance Tribe and the Secretary (with or without amendment as required by § 137.363) may do one or more of the following:

(1) Mitigate adverse environmental effects;

(2) Alter the project scope of work; and/or

(3) Add additional program and/or project funding, including seeking supplemental appropriations.