75-5-320. Temporary water quality standards variances. (1) Except as provided in 75-5-222(2) and 75-5-313, the department may adopt rules providing criteria and procedures for the department to issue a temporary variance to water quality standards if:

(a) a variance will not result in a lowering of currently attained, ambient water quality;

(b) the department rules are consistent, as necessary, with federal rules that authorize states to adopt variances from standards, including but not limited to 40 CFR 131.14; and

(c) (i) a permittee cannot reasonably expect to meet a water quality standard during the permit term for which the variance is approved; and

(ii) a permit compliance schedule is not feasible to preclude the need for a variance during the permit term for which the variance is approved.

(2) In order to receive a temporary variance, a permittee shall evaluate facility operations and infrastructure to maximize pollutant reduction through an optimization study. The variance must require the implementation of optimization study actions as terms and conditions of the discharge permit.

(3) The department shall review a temporary variance issued pursuant to this section at least once every 5 years and may continue, modify, or terminate the temporary variance as a result of the review.