S.C. Code Regs. § 61-79.265.K.222

Current through Register Vol. 48, No. 5, May 24, 2024

Section 61-79.265.K.222 - Action leakage rate

(a) The owner or operator of surface impoundment units subject to 265.221(a) must submit a proposed action leakage rate to the Department when submitting the notice required under 265.221(b). Within 60 days of receipt of the notification, the Department will: Establish an action leakage rate, either as proposed by the owner or operator or modified using the criteria in this section; or extend the review period for up to 30 days. If no action is taken by the Department before the original 60 or extended 90 day review periods, the action leakage rate will be approved as proposed by the owner or operator.

(b) The Department shall approve an action leakage rate for surface impoundment units subject to 265.221(a). The action leakage rate is the maximum design flow rate that the leak detection system (LDS) can remove without the fluid head on the bottom liner exceeding 1 foot. The action leakage rate must include an adequate safety margin to allow for uncertainties in the design (e.g., slope, hydraulic conductivity, thickness of drainage material), construction, operation, and location of the LDS, waste and leachate characteristics, likelihood and amounts of other sources of liquids in the LDS, and proposed response actions (e.g., the action leakage rate must consider decreases in the flow capacity of the system over time resulting from siltation and clogging, rib layover and creep of synthetic components of the system, overburden pressures, etc.).

(c) To determine if the action leakage rate has been exceeded, the owner or operator must convert the weekly or monthly flow rate from the monitoring data obtained under 265.226(b), to an average daily flow rate (gallons per acre per day) for each sump. Unless the Department approves a different calculation, the average daily flow rate for each sump must be calculated weekly during the active life and closure period, and if the unit closes in accordance with 265.228(a)(2), monthly during the post-closure care period when monthly monitoring is required under 265.226(b).

S.C. Code Regs. 61-79.265.K.222

Amended by State Register Volume 10, Issue No. 1, eff January 24, 1986; State Register Volume 17, Issue No. 12, eff December 24, 1993.