ID H0392

Establishes a 10% threshold for assimilative capacity decrease as the baseline for determining insignificant degradation, with cumulative decreases exceeding 10% from July 1, 2011 baseline constituting significant degradation.

Allows the Department of Environmental Quality to determine degradation as insignificant if cumulative decrease in assimilative capacity is 10% or less, considering the size, character, and magnitude of effects on the receiving stream.

Provides that if degradation is determined to be insignificant, no further Tier II analysis for source controls, alternatives analysis, or socioeconomic justification is required.

Authorizes the department to request additional information from applicants to determine whether a proposed change in activity or discharge constitutes insignificant degradation.

Declares an emergency, making the act effective immediately upon passage and approval.