DSHW-2004-007538 - 0901a06880160758

MODULE V - GROUNDWATER MONITORING

V.A. POSTCLOSURE GROUNDWATER MONITORING

V.A.1. The Permittee shall monitor groundwater in the uppermost aquifers as described in Attachment 4 and as described below, in a manner that will monitor the release of hazardous constituents
from the M-136 Burning Area, in compliance with R315811.5(b)(2), R31587, and R31586 during the post-closure care period as defined in Condition V.C.4.

V.A.2. Solid waste management units (SWMUs) may be subject to provisions of this Module. The Executive Secretary shall determine which SWMU's may be subject to some or all of the provisions
of this Module. The Permittee must comply with the provisions of R31586.12.

V.A.3. The Permittee must follow all of the provisions listed under R31586, Groundwater Protection, and as defined by the conditions of this permit. For the purposes of this permit,
the R31586 rules for groundwater protection shall apply to the M-136 Burning Area.

V.A.3.a. The Point of Compliance is a vertical surface located at the hydraulically downgradient boundary of the M-136 Burning Area. The present compliance point wells are listed in
Condition V.A.4.

V.A.3.b Upon approval of a Corrective Action Plan (CAP), per Condition VI.A, and as part of the CAP, the Permittee shall provide compliance wells for the corrective action systems which
shall follow the provisions of Module V. These monitoring wells shall also be identified as compliance wells.

V.A.4. The Permittee shall maintain a groundwater monitoring system which consists of monitoring wells situated hydraulically upgradient and downgradient of M-136, and in or near identified
areas of contamination. The hydraulically upgradient monitoring wells that shall serve as background monitoring wells, are: C-6, C-8, and A-10. The hydraulically downgradient monitoring
wells, that shall be the compliance point monitoring wells, are: A-2, A-3, A-4, A-5, A-6, A-7, C-1, C-2, and B-9. The monitoring well system and well locations are presented in Attachment
4. The Permittee may add wells as specified in Conditions V.D.1.i. and j.

V.A.5. The following compliance monitoring wells situated hydraulically upgradient
and downgradient of the M-136 Burning Area are divided into Groups A and B based upon the uppermost aquifers identified in Attachment 4:

Group A: C-6, C-8, A-4, A-5, A-6, A-7, C-1, C-2,.

Group B: A-10, A-2, A-3, B-9.

V.A.6. The Permittee shall monitor groundwater as it enters and exits each of the affected areas. The purpose of this monitoring is to ensure that the treatment or containment is removing
the hazardous constituents specified in Condition V.B.1.a of this module to a level below the concentration limits listed in Attachment 7 and concentration levels to be established in
Module VI. Issuance of this permit constitutes the approval of the Executive Secretary to allow treatment and containment methods to remove hazardous constituents from the groundwater.

V.A.7. The Permittee shall monitor and record the rate and volume of the flow of groundwater as it is pumped from compliance and monitoring wells and as it enters and exits the affected
areas from M-136.

V.A.8. If the Permittee chooses to use a groundwater treatment system and if for any reason the system is unable to operate for a period of ninety (90) days or longer and if during this
ninety (90) day period the groundwater treatment system contains untreated groundwater, the Permittee must provide for the removal and disposal of the groundwater from the system as
specified in Conditions VI.E.3.a, b, and c.

V.A.9. The Permittee shall monitor and record the concentration of constituents listed in Condition V.B.1.a. in the unconfined and confined aquifers, and shall submit maps to show the
concentration of each of the hazardous constituents in these two aquifers as specified in Condition V.F.4.

V.B. REQUIRED PROGRAM

V.B.1. The Permittee shall conduct a monitoring and response program as follows for the M-136 subject to these provisions:

V.B.1.a. The Permittee has submitted M-136 groundwater quality assessment reports. These assessment reports have indicated that the following hazardous
Thiokol Corporation
PC Permit
Final: Sept. 1, 1992
Last Revision: April 1, 2004

Module V - page 2