(1) Legal demands usually exist on the source of supply or its downstream tributaries and may be affected by a proposed water right application, including prior appropriations and water reservations. These existing legal demands will be senior to a new application and the senior rights must not be adversely affected:
(a) an applicant may use a plan for mitigation or aquifer recharge, as generally defined in 85-2-102, MCA, as a means of showing water is legally available.
(2) The department will identify the existing legal demands on the source of supply and those waters to which it is tributary and which the department determines may be affected by the proposed appropriation.
(a) For groundwater appropriations, this shall include identification of existing legal demands for any surface water source that could be depleted as a result of the groundwater appropriation.