What is the difference between a Mitigation Strategy and a Rationale and in what situations are they required?

Rationale Requirements
A rationale is a brief statement of reason, or a logical basis, to justify a course of action proposed by a proponent. A rationale is required when an application for an oil and gas activity is not consistent with the POMs provided by the Commission for a specific environmental value. Rationales must:

Be prepared by a Qualified Professional
Include an explanation of why the oil and gas activity cannot be planned to be consistent with the planning and operational measures provided by the Commission.
Provide a detailed description of the alternate measures planned for the activity and describe how desired outcomes specified in the planning and operational measures will be achieved.

Mitigation Strategy Requirements
A Mitigation Strategy is a formal document capturing a proponent’s commitment to mitigation and monitoring, including mitigation goals, mitigation actions and the specific measures that will be carried out. A mitigation strategy is required when a proposed activity is within 100 metres of water works and/or water supply well, in cases where the Commission has not defined POMs for the environmental value overlapped (impacted), or where the ABA Status is either enhanced management or regulatory policy. A Mitigation Strategy may also be required in specific circumstances at the discretion of a statutory decision maker. Mitigation Strategies must be prepared in accordance with Appendix B of the Environmental Protection and Management Guideline.