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Home My WebLink About20131200 Ver 6_More Info Received_20181017CLearWaLer��,.\,v� October 16, 2018 C1earWater Environmental Consultants, Inc. www.cwenv.com Ms. Karen Higgins Division of Water Resources 401 & Buffer Permitting Branch 512 N. Salisbury St. Raleigh, NC 27604 Dear Ms. Higgins: Please reference the "Request for Additional Information" letter dated August 27, 2018 (Attachment A) sent by the NC Division of Water Resources (DWR) The subject property is owned by Tryon Equestrian Partners, LLC located in Polk County, North Carolina. In order to satisfy the conditions of a permit modification request to DWR 401 Water Quality Certification (DWR# 20131200 v6) submitted on April 27, 2018 DWR has requested the following information: Required Response 1: "During a site inspection conducted on August 8, 2018, the area below the 60 -inch bypass outfall structure showed signs of erosion down to, and along, the streambank. The Division expressed concern about this area in the Notice of Violation issued March 29, 2018, and during an on-site meeting on April 11, 2018. Please provide a stabilization and monitoring plan for the area below the 60 -inch bypass outfall. " The stabilization plan includes armoring the toe of slope, matting and seeding, and installation of live stakes. The monitoring plan includes as -built documentation of stream dimension (cross-sections) and visual assessment (photo -points), with post- construction annual monitoring be repeated for a period of three (3) years. Please refer to the attached stabilization detail (Figure 1), and the monitoring plan view map (Figure 2). The 60" stormwater bypass was installed in March 2018. However, due to construction, the associated stormwater treatment and management systems did not come online until September 7, 2018. A diversion weir was added to the drainage system in October 2018, so that stormwater will only flow out of the 60" bypass outlet when rainfall exceeds the stormwater management design capacity. The daily flow of the culverted stream now outlets at its originally permitted location. The diversion weir should significantly reduce the frequency and duration of overland flow below the 60" stormwater outlet, thereby reducing the potential for additional erosion in the area. Stabilization Plan Odom Engineering has provided a design for stabilizing approximately 20 linear feet of stream bank below the bypass outfall. The stream bank is showing signs of erosion down to and along the stream bank. Stabilization of this reach will include the placement of boulders at least 24 inches 32 Clayton Street Asheville, NC 28801 828-698-9800 Tel to stabilize the toe of slope along the eroded bank, to provide armoring against erosive flows. The remaining stream bank will be seeded with temporary erosion control seed mix, permanent shade tolerant seed mix, and protected with coir fiber matting held in place with a combination of eco - stakes and live stakes. Please refer to the attached stabilization detail (Figure 1). Monitoring Plan CEC will conduct monitoring of an approximately 200ft reach to gather data necessary for regulatory review. The reach will span approximately 100ft upstream and downstream from the 20ft repair section. Geomorphic monitoring of stream dimension will include a survey of four (4) stream cross-sections. The cross-section surveys will be located as indicated on Figure 2, with one cross section located above the repair, one located below the repair, and two located within in the repair section. The cross-section surveys will be performed using a laser -level, reel tape, and stadia rod. Permanent capped rebar pins will be placed on each bank for each cross-section to serve as a spatially referenced control for subsequent monitoring. The location of these control pins will be recorded with a sub -meter accuracy GPS and permanently marked with PVC pipe and survey flagging. Photographic reference points (photo -points) will be used to visually document stream conditions and will include both a downstream facing photo and an upstream facing photo at each photo reference point. Photo -points will be established at eight (8) stations along the length of the 200 ft reach beginning at the stormwater bypass outlet and ending at a small footbridge downstream from the repair section. The photo -points will be recorded with a sub -meter accuracy GPS and permanently marked with a PVC stake and survey flagging. The photographer will make a reasonable attempt to capture the same perspective in each photo -point location annually. Please refer to Figure 2 for the proposed location of monitoring features. Report Preparation and Submittal CEC will prepare four (4) reports containing all gathered survey and photographic data. These reports include: (1) as -built documentation report, (3) post -construction monitoring reports in 2019 through 2022. The reports will be submitted to the DWR in accordance with their standards for stream monitoring. Information gathered and presented will be based on set reference points so that stability over time can be evaluated. Please do not hesitate to contact me at 828-698-9800 if you have any questions or comments. Alea K Tuttle, P.W.S. Biologist cc: Steve Kichefski, Andrew Moore A" a�__4x R. Clement Riddle, P.W.S. Principal U.S. Army Corps of Engineers N.C. Division of Water Resources Tryon Equestrian Center Stream Stabilization and Monitorinc �J + Begin Monitoring Reach at Bridge, approximately 100ft upstream from j y Bank Stabilization f ter% Stormwater Bypass Bank Stabilization approximately 20 ft PP5 PPlt �Q� End Monitoring Reach approximately 100 ft downstream from Bank Stabilization Legend'--.. Photo Points (PP) Cross -Sections (XS) N r Bank Stabilizaiton Stormwater Bypass J� ; - 1 ft countour Polk County, North Carolina 0 25 50 100 , Feet , 1 CLearWater 32 Clayton Street Asheville, North Carolina 28801 Monioring Plan View Map Figure 2 A TOP OF BANK d ct d cr LIVE STAKES (TYP.) - d ADD ECO STAKES AS NEEDED FOR MINIMUM 2' SPACING TOE OF BANK �— STREAM FLOW PLAN VIEW PL ANTINEV SC.Ff_DI_LE I. SOIL SURFACE ROU13HENIN6 2. SEEDING OF BANK WITH TEMPORARY AND PERMANENT RIPARIAN SEED MIX. 3. INSTA -LATION OF EROSION CONTROL MATERIAL A66ORPIN6 TO MANLFAGTUREF'S SPECIFICATIONS A. TOE PROTECTION INSTALLATION 5. LIVE- -STAKIWv FINISHED GRADE APPROVED SPECIES OF LIVE-STAKES, WITH 2 LEAF SCARS OR NODES ABOVE GROUND 12' MINIMUM EROSION CONTROL MATERIAL / (COIR MATTING) TOE PROTECTION 24 INCH NOMINAL SIZE BOULDERS NORMAL -L WATER LEVEL 1/2 BOULDER �— EXISTING STREAM BANK STABILIZATION DETAIL CHANNEL BOTTOM (NOT TO SCALE) Odom 60" BYPASS OUTFALL Engineering STREAM BANK OCTOBER 11, 2018 PLLC STABILIZATION DETAIL 169 Oak Street, Forest Cily. N.C. 28043 (FIGURE 1 ) ph: 828.247.4495 fax: 82 8.247.4498 SCALE: N.T.S. ATTACHMENT A ROY COOPER G~rnor MICHAEL S. REGAN Setrrrory LINDA CULPEPPER tntertm arraor NORTH CAROLINA Environmental Quality August 27, 2018 DWR# 20131200 v6 Polk County Tryon Equestrian Partners, LLC Attn: Mr. Jeff Brown 2659 Sandy Plains Road Tryon, NC 28782 Subject: REQUEST FOR ADDITIONAL INFORMATION Tryon International Equestrian Center Dear Mr. Brown: On May 18, 2018, the Division of Water Resources (Division) received your application dated April 27, 2018, requesting modification of an Individual Water Quality Certification from the Division for the subject project. On July 23, 2018, and August 3, 2018, the Division received your response to our request for additional information issued on June 28, 2018. The Division has determined that your application is incomplete and cannot be processed. The application is on - hold until the following information is received: 1. During a site inspection conducted on August 8, 2018, the area below the 60 -inch bypass outfall structure showed signs of erosion down to, and along, the streambank. The Division expressed concern about this area in the Notice of Violation issued March 29, 2018, and during an on-site meeting on April 11, 2018. Please provide a stabilization and monitoring plan for the area below the 60 -inch bypass outfall. Pursuant to Title 15A NCAC 02H .0502(e), the applicant shall furnish all of the above requested information for the proper consideration of the application. Please respond in writing within 30 calendar days of receipt of this letter by sending one (1) copy of all of the above requested information to the 401 & Buffer Permitting Branch, 1617 Mail Service Center, Raleigh, NC 27699-1617 OR by submitting all of the above requested information through this link: https://edocs.deg.nc.gov/Forms/Supplemental-Information-Form (please note that the DWR# requested on the link is referenced above). D_EQ�, North Carolina Department of Environmental Quality I Division of Water Resources 512 North Salisbury Street 11617 Mail Service Center I Raleigh, North Carolina 276991617 919.707.9000 Tryon Equestrian Partners, LLC Request for Additional Information August 27, 2018 Page 2 of 2 If all of the requested information is not received within 30 calendar days of receipt of this letter, the Division will be unable to approve the application and it will be returned. The return of this project will necessitate reapplication to the Division for approval, including a complete application package and the appropriate fee. Please contact Andrew Moore at 828-296-4684 or Andrew.W.Moore@ncdenr.gov if you have any questions or concerns. Sincerely, , ��1XJV 1 Karen Higgins, Supervisor 401 & Buffer Permitting Branch cc: Clement Riddle, ClearWater Environmental Consultants, Inc. (via clement@cwenv.com) Steve Kichefski, USACE Asheville Regulatory Field Office (via Steven.1.kichefski@usace.army.mil) DWR ARO 401 file DWR 401 & Buffer Permitting Branch file Filename: 131200v6Tryon Equestria nCenter(Pol k)_IC_H OLD_2