(a) The owner or
operator of surface impoundment units subject to subsection
11-265-221(a) must
submit a proposed action leakage rate to the director when submitting the
notice required under subsection
11-265-221(b). Within sixty days of receipt of
the notification, the director 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 thirty days. If no action is
taken by the director before the original sixty or extended ninety day review
periods, the action leakage rate will be approved as proposed by the owner or
operator.
(b) The director shall
approve an action leakage rate for surface impoundment units subject to
subsection
11-265-221(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 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 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 subsection
11-265-226(b), 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 closes in accordance with
paragraph 11-265-228(a)(2), monthly during the post-closure care period when
monthly monitoring is required under subsection
11-265-226(b).
