Appendix K

Authorization Letters from WDEQ and SDDENR

June 13, 2016

Stuart Wevik Black HIils Energy - South Dakota, Black HIils Power Inc PO Box 1400 Rapid City, SD 57709

Dear Mr. Wevik:

DEPARTMENT OF ENVIRONMENT and NATURAL RESOURCES

JOE FOSS BUILDING 523 EAST CAPITOL

PIERRE, SOUTH DAKOTA 57501-3182

denr.sd.gov

Thank you for submitting your Notice of Intent for the general storm water discharges associated with construction activities permit. This lefter grants you coverage under this permit for the project listed below in Pennington County, SD. This coverage does not relieve you from complying with other state and local requirements or from obtaining other required permits. The Notice of Intent did not identify a contractor that would be responsible for erosion and sediment control on the project. If a contractor responsible for erosion and sediment control is added, a contractor certification form must be submitted identifying the contractor. The contractor will then be considered a co-permittee for permit compliance. You must maintain your site in compliance with the permit conditions. Refer to Section 3.0 for effluent limits and Section 4.0 for Pollution Prevention Plan requirements. Your facility Permit No. is SDR10H659. Please refer to this number in future correspondence.

Project Information Michael Pogany - Contact Person Teckla - Osage - Rapid City 230 kV Transmission Line Var, Sec.Var, TVar, RVar 44.121069 Lat., - I 03 .26025 Long. Rapid City, SD

Please check to be certain the above project is the same as listed in the Notice oflntent.

Please Note: The SDDENR is in the process of reissuing the General Permit for Storm Water Discharges Associated with Construction Activities, which expired on January 31, 2015. The general permit is administratively continued until the new general permit is issued. This letter grants you full coverage under the current permit and automatic coverage under the new general permit. You will be notified when the new general permit is issued.

Thank you for preserving the natural resources of South Dakota. If you have any questions or need any guidance, please contact me at (605) 773-3351 or 1-800-SDSTORM (737-8676).

Sincerely,

William Marcouiller Natural Resources Engineer Surface Water Quality Program

c: Mary Bosworth, City of Rapid City, 300 6th St., Rapid City, SD 57701-2724

Permit No.: SDR10H659

SOUTH DAKOTA DEPARTMENT OF ENVIRONMENT AND NATURAL RESOURCES

JOE FOSS BUILDING 523 EAST CAPITOL A VENUE

PIERRE, SOUTH DAKOTA 57501-3181

GENERAL PERMIT FOR STORM WATER DISCHARGES ASSOCIATED WITH CONSTRUCTION ACTIVITIES

Authorization to Discharge Under the Surface Water Discharge System

In compliance with the provisions of the South Dakota Water Pollution Control Act and the Administrative Rules of South Dakota (ARSD) Chapters 74:52:01 through 74:52:11, operators of storm water discharges from construction activities, located in the State of South Dakota are authorized to discharge in accordance with the conditions and requirements set forth herein.

This General Pennit shall become effective on February 1, 2010.

This General Permit and the authorization to discharge shall expire at midnight, January 31, 2015.

Signed this 31st day of December, 2009

Authorized Permitting Official

Steven M. Pirner Secretary Department of Environment and Natural Resources

Matthew H. Mead, Governor

June 15, 2012

Department of Environmental Quality

To protect, conserve, and enhance the Quality of Wyoming's environment for the benefit of current and future generations

re: Renewal of the large construction general permit for storm water discharges

Todd Parfitt, Director

Please find the attached Letter(s) of Authorization (LOA) which renews coverage of your facility under the recently reissued large construction general storm water permit {LCGP}. A copy of that permit was sent to you this past May along with other renewal information. You may obtain additional copies of the permit from the DEQ website at http://deg.wyoming.gov/wgd/storm-water­permitting/resources/construction-general-permits/ or by calling me at 307-777-7570 (barb.sah l@wyo.gov) or John Gorman at 307-777-5622 (john.gorman@ wyo.gov).

Please be sure to read and understand the requirements of the new permit, there have been some changes from the previous permit. Many of the changes were noted in the renewal package you recently received.

If we can be of further assistance, please let us know.

Sincerely,

Barbara L. Sahl Storm Water Program Coordinator Water Quality Division barb.sahl@wyo.gov

enclosure: letter(s) of authorization

cc: chron

/bis

C:\BSAHL \Storm_ Water\Construction\CGP _ 2016\Final_ LCGP\LOA_ tranmittal_letter _ CG P2016.doc

200 West 17th Street · Cheyenne, WY 82002 · http://deq.wyoming.gov · Fax (307)635-1784

ADMIN?OUTREACH ABANDONED MINES AIR QUALITY INDUSTRIAL SITING LAND QUALITY SOLID & HAZ. WASTE WATER QUALITY (307) 777-7937 (307) 777-6145 (307) 777-7391 (307) 777-7369 (307) 777-7756 (307) 777-7752 (307) 777-7781

Matthew H. Mead, Governor

Department of Environmental Quality

To protect, conserve, and enhance the Quality of Wyoming's environment for the benefit of current and future generations

Authorization to Discharge Storm Water Associated

Large Construction Activities

Under the Wyoming Pollutant Discharge Elimination System

Todd Parfitt, Director

In compliance with the provisions of Chapter 2 of the Wyoming Water Quality Rules and Regulations, the Wyoming Environmental Quality Act and the federal Water Pollution Control Act,

Black Hills Power, Inc.

Teckla-Osage-Rapid City 230 kV Transmission Line Section 34, Township 42 North, Range 73 West to Section 15, Township 46 North, Range 60 West., Campbell County

and located within the State of Wyoming which has or may discharge storm water associated with Construction Activities, is hereby authorized to discharge to the surface waters of the State of Wyoming in accordance with the requirements of this permit which was issued April 22, 2016.

Coverage under the general permit expires 12/29/2017.

This facility has been assigned permit authorization number WYR105257,

Authorization under this general permit is effective beginning 6/13/2016.

Discharges from dewatering of collected storm water and minor amounts of ground water from excavations and depressions are permitted provided that requirements specified in Part 7.14 are followed and the necessary BMPs are installed and effective. Discharges that consist of process or wastewaters or more than minor amounts of ground water must be covered under a separate WYPDES permit specifically for those discharges.

If a copy of the general permit was requested, it is attached. If you have any questions regarding the conditions of your permit, contact Barb Sahl at (307) 777-7570 or John Gorman at (307) 777-5622. Or visit the storm water website at http://deq.wyoming.gov/wqd/storm-water-permitting/

Authorized Signature / Department of Environmental Quality/Water Quality Division

Mailing Address: Stuart Wevik PO Box 1400 Rapid City, SD 57702

200 West 17th Street · Cheyenne, WY 82002 · http://deq.wyoming.gov · Fax (307)635-1784 ADMIN?OUTREACH ABANDONED MINES AIR QUALITY INDUSTRIAL SITING LAND QUALITY SOLID & HAZ. WASTE WATER QUALITY

(307) 777-7937 (307) 777-6145 (307) 777-7391 (307) 777-7369 (307) 777-7756 (307) 777-7752 (307) 777-7761