MT SB436

Adds new definition of "combined appropriation" to mean water appropriated from the same source aquifer by two or more groundwater developments that could have been accomplished by a single appropriation, allowing the department to aggregate wells and springs for permit threshold calculations

Revises permit exemption thresholds outside stream depletion zones: maintains 35 gallons per minute maximum but changes annual volume limit from flat 10 acre-feet to 1 acre-foot per 2 acres of a parcel, not to exceed 10 acre-feet total

Revises permit exemption thresholds within stream depletion zones: maintains 20 gallons per minute maximum but changes annual volume limit from flat 2 acre-feet to 1 acre-foot per 2 acres of a parcel, not to exceed 10 acre-feet total

Clarifies that combined appropriations exceeding the applicable acre-feet thresholds (10 acre-feet outside stream depletion zones, 2 acre-feet within) require a permit regardless of flow rate

Requires the secretary of state to send a copy of the act to each federally recognized tribal government in Montana