(A) The director will approve an action leakage rate for surface impoundment units subject to paragraph (C) or (D) of rule 3745-56-21 of the Administrative Code. The action leakage rate is the maximum design flow rate that the leak detection system can remove without the fluid head on the bottom liner exceeding one 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 leak detection system, waste and leachate characteristics, likelihood and amounts of other sources of liquids in the leak detection system, 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.).
(B) 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 paragraph (D) of rule 3745-56-26 of the Administrative Code to an average daily flow rate(gallons per acre per day) for each sump. Unless the director 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 is closed in accordance with paragraph (B) of rule 3745-56-28 of the Administrative Code, monthly during the post-closure care period when monthly monitoring is required under paragraph (D) of rule 3745-56-26 of the Administrative Code.