| October 25, 2000
Deborah A. Schumann RE: Review of the Draft Issuance NPDES/SDS
Permit Dear Ms Shumann: Thank you for the opportunity to review and comment on the Draft Issuance of the NPDES/SDS Permit Application No. MN 0065404 Light Rail Transit South Portal Construction and Related Airport Expansion Dewaterting Projects. The above referenced draft NPDES/SDS permit is a general, five year permit under which all dewatering projects associated with the MAC airport expansion project construction could eventually be covered. The present form of the draft permit specifically addresses only the discharge of impacted groundwater associated with construction of the South Portal of the LRT corridor through the Minneapolis /St. Paul Airport property (Figure 1). However, the draft permit allows for "minor modification to authorize additional pump-out sites as part of the MAC expansion project". Therefore, this permit could potentially cover any and all construction projects associated with the MAC expansion project over the next five years. There is currently no mechanism through which the MCWD might review or comment on any such modifications. According to the MAC engineer, there is currently
only one MAC storm sewer outfall located within MCWD jurisdiction, Mother
Lake outfall 010. Deborah Schumann of the MPCA and MAC engineers both
agree that discharge to that outfall is not covered under this permit
and would not be covered under any modifications to the permit. Deborah
indicated that the effluent limitations set forth in this permit are too
high for discharge to Mother Lake and were To eliminate any ambiguity we recommend that a statement be added to explicitly mandate that the effluent limitations of this permit were established to cover discharges to the Minnesota River only and that there will be no discharge allowed to Mother Lake under this permit. 1. LRT South Portal Under this permit, groundwater
extracted during construction of the LRT South Portal will be discharged
to the TMDL-listed Minnesota River via MAC storm sewer outfall 040 which
is located just outside MCWD jurisdiction, within the jurisdiction of
the Lower Minnesota River Watershed District. The 2. Quality and Quantity of Discharged Ground Water
Though "This permit does not authorize MAC to appropriate ground water
or to work in the water table." the flexibility of the NPDES/ SDS permit
conditions and MCWD Rule N necessitate some discussion of the effect of
dewatering on surface water features. The effects To address any potential effects of dewatering
on surface water features within MCWD jurisdiction, MCWD requests that
the NPDES permit conditions include the expansion of The Highway 17-35
Vehicular Tunnel Construction Dewatering Monitoring and Mitigation Plan
to include all work done under the scope of this Requested addition to Page 3 Paragraph 5 is indicated in bold print: "This permit allows for minor modification to authorize additional pump-out sites as part of the MAC expansion project. At least forty-five calendar days prior to commencement of discharge to the MAC storm sewer system, the Permittee shall provide the MPCA and MCWD with the information necessary to evaluate the additional waste stream." Further, the MCWD would like access to all information necessary to evaluate the impacts of the proposed modification and would also like the opportunity to provide comments on the proposed modification prior to MCPA approval of the modification. Please feel free to contact me at 612-471-0590 should you have any questions. Sincerely.
L Eric Evenson, District Administrator cc: Chuck Holtman, Smith Parker |