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Home My WebLink About20201604 Ver 1_NOV Response_202306055410 Trinity Road P 919.866.4951 63 TIMMONS GROUP Suite h, Fww.Um9.56.c Raleigh, NC 27607 www.timmons.com April 3, 2023 VIA ELECTRONIC MAIL David Bailey U.S. Army Corps of Engineers — Wilmington District Raleigh Regulatory Field Office 3331 Heritage Trade Drive, Suite 105 Wake Forest, North Carolina 27587 Zach Thomas NCDEQ — Division of Water Resources Raleigh Regional Office 3800 Barrett Drive Raleigh, NC 27609 Re: Response to Requests for Additional Information Jasper Place (fka Gannon Ave) USACE AID: SAW-2020-01464 DWR ID: 20201604 (Approx. 53 acres) Wake County, North Carolina Dear Mr. Bailey and Mr. Thomas, On behalf of Lennar Homes, we are providing a response to the Notification of Permit Non - Compliance letter dated March 3, 2023, for Jasper Place, an approximately 53-acre site located along W. Gannon Avenue in Zebulon, Wake County, North Carolina (the "Site"). The proposed sewer line crossing identified as Impact 1 C was authorized as a temporary stream impact, with the line to be buried beneath the existing stream channel and bed and banks restored to pre -construction contours. Instead, as noted in the Notification, the sewer line was installed such that it is sitting above the stream bottom. In order to address the comments in the Notification, we propose to install a cross vane up -stream of the crossing which will result in pool formation beneath the existing pipe. See Attachment No. 1 for preliminary plans. Following installation, we will stabilize and replant the banks with native vegetation. We will also conduct additional inspections to ensure that any debris buildup is removed. Set forth below are the requests from the Notification blue italics, followed by our responses. ENGINEERING I DESIGN I TECHNOLOGY Response to Requests for Additional Information April 3, 2023 Page 2 a) Propose a plan to install, or correct the existing installation of, the utility line in such a way that this crossing would comply with all terms and conditions of current NWP 58 (Utility Line Activities for Water and Other Substances). Following discussion and Corps approval of a plan, a timeframe for completion of the resulting activities will be provided by the Corps. We propose to install a cross vane up -stream of the sanitary sewer crossing which will result in pool formation beneath the existing pipe. The proposed timeline for the project is as follows: • Final Site Plans, including Restoration Plan — within 2 months of agency preliminary plan approval. • Construction — within 2 to 3 months of agency approval of final site plans, depending upon contractor availability at the time of agency approval. This includes completion of the restoration plan and stabilizing and revegetating the area. Areas temporarily impacted beyond the utility right-of-way for cross vane installation, if required, will be temporarily seeded with native herbaceous species, then planted with woody vegetation winter of 2023/2024, no later than March 2024. No woody plants are proposed to be installed within the maintained utility right-of-way. Compliance with the terms and conditions of NWP 58 are addressed below: General Condition 2 — Aquatic Life Movement The proposed plan will ensure continued aquatic life movement by creating a pool which allows low flows to continue beneath the steel casing. This technique is known to be utilized to enhance aquatic habitat through creation of scour pools. The cross vane will mimic natural stream riffle -pool sequencing. The project site is in an area with beaver activity and, therefore, aquatic life is regularly subject to natural damming. However, this solution proposes quarterly inspection and maintenance to ensure no artificial damming occurs along the steel casing. General Condition 9 — Management of Water Flows The proposal allows for the pre -construction course, condition, capacity, and location of the stream to be maintained to the maximum extent practicable by maintaining the stream location and only modifying a section of the stream to mimic the natural riffle -pool sequence. The longitudinal profile of the stream demonstrates riffle and pool elevations consistent with those naturally present within the stream in the immediate vicinity of the project area. The pool beneath the steel casing will facilitate passage of low flows. The existing stream contains a wide floodplain, with flows from the 10-year storm event rising approximately 6-ft above stream banks across an approximately 580-ft wide area. Therefore, the steel casing will not restrict high flows and the proposed design is preferred to an aerial line, which poses the greater potential for restriction from the longer section of exposed line and associated support piers. Response to Requests for Additional Information April 3, 2023 Page 3 General Condition 13 — Removal of Temporary Structures and Fills The surrounding stream bed, bank, and wetland areas have been returned to pre - construction elevations, stabilized, and revegetated with native species. A portion of the stream bank has been permanently altered from the installation of the steel casing. The line has been stabilized with concrete immediately beyond the top of bank on either side of the stream. The proposed solution will maintain this permanent impact and will include a restoration plan. The bank will be reconstructed, seeded, and matted around the line. The cross vane will provide additional bank protection at the utility crossing as this portion of the bank will become an area of deposition with higher flows concentrated in the center of the channel. Temporary access will be required for installation (exact area to be determined during final design). Following installation, the area will be stabilized and re -planted with native riparian seed. No woody species will be introduced into the sanitary sewer easement. If temporary access impacts are required beyond the easement, woody species will be planted. General Condition 23(a) — Mitigation — Avoidance and Minimization The proposed plan will avoid and minimize adverse effects to the maximum extent practicable. Installation of the cross vane and resulting pool beneath the steel casing will mimic natural stream conditions. The area will be stabilized and revegetated following installation. The proposed plan allows for avoidance of further impacts from removing the steel casing and installing permanent aerial line piers across the surrounding floodplain and wetland. Regional Condition 3.10 — Restoration of Temporary Impacts to Stream Beds This condition is no longer included in the present-day Utility Crossing NWP, NWP 58. The stream bed has been restored to pre -project elevations and widths. The proposed solution will create a pool beneath the steel casing, mimicking the natural pools present in the stream. Regional Condition 3.11 — Restoration of Temporary Impacts to Stream Banks This condition is no longer included in the present-day Utility Crossing NWP, NWP 58. However, the proposed cross vane directs flow away from the banks and will create a pool beneath the steel casing. The proposed cross vane through the redirection of stream flow to the center of the channel will provide long term bank stabilization a distance of the arm length both up and downstream of the installed structure. This allows for vegetation to be installed during restoration to become established. Response to Requests for Additional Information April 3, 2023 Page 4 b) Propose a restoration plan, including a planting plan, for this stream bank area for Corps approval using regionally appropriate native riparian vegetation. Note that such planting will also need to meet NCDWR specifications. The required timeframe for completion of this work will follow item a. above. The plan will include a restoration and planting plan for the steel casing crossing and cross vane installation area. Please see the timeline included in response item a. above. As proposed with the initial application, the portions of the stream bank and surrounding riparian buffer disturbed by this construction will be stabilized with C-700 coir matting and revegetated with native herbaceous species as is required for sewer line easements. Cross vane installation may require temporary impacts beyond the utility right-of-way. If required, areas beyond the sewer line easement within the stream buffers will have temporary stabilization with native seeding and a permanent re -planting plan with woody species. c) Please self -inspect the remaining impacts authorized via the above -referenced NWP 12/14 verifications and additional NWP 14 verification and provide pictures and a brief narrative of their construction status and compliance status per the authorized plans, Special Conditions, and NWP General and Regional conditions. The remaining impacts authorized under the original and additional verifications, which involve road widening activities, were visually inspected on March 22, 2023. During the review of field conditions, we determined that the stakes for the road widening impact were placed in the wrong location and that additional temporary wetland impacts occurred. No fill material was placed in the area outside of the originally permitted impact area. Lennar immediately removed and reinstalled the silt fence and tree protection fence at the boundary of the permitted impact area and installed a wetland seed mix and natural duff (pine straw) in the temporarily impacted area outside of the permitted impact. This activity was completed on March 29, 2023. Photos of this inspection and the corrective actions are attached for reference. See Attachment No. 2. Permanent riparian buffer, wetland, and stream Impact 1 from the second authorization are currently in progress, with fill and grading work still being completed. Stream impacts have not occurred yet for the permanent impacts required in order to extend the existing culverts. It is anticipated the road widening and culvert extension will be complete by approximately August 2, 2023. I) DWR — Riparian Buffer Concerns Impact 1C in the initial permit for this Site included 1,844-sq ft of permanent Zone 1 impact and 1,303-sq ft of permanent Zone 2 impact of riparian buffer for the 30-ft wide utility corridor. Per the Neuse River Buffer Rules, new sewer lines consisting of a perpendicular stream crossing with a construction corridor of less than or equal to 40-ft wide and a permanent Response to Requests for Additional Information April 3, 2023 Page 5 maintenance corridor that is equal to or less than 30-ft wide are deemed allowable. The initial approval was for a 30-ft wide corridor serving as both the construction and permanent maintenance corridor. The proposed solution may require widening the construction corridor to 40-ft wide for installation of the cross -vane, following which the portion outside of the 30-ft wide permanent maintenance corridor will be stabilized, revegetated, and planted with woody species. Therefore, the proposed solution still qualifies as deemed allowable. Please review the preliminary plans and self -inspection photographs and contact Lauren Norris - Heflin at (919) 866-4943 or lauren.norris-heflin@timmons.com if additional information is required. Sincerely, Timmons Group Lauren Norris -Heflin Environmental Project Manager Enclosures Attachment 1 Preliminary Plans Attachment 2 Site Inspection Photographs 42 BOULDER STABILIZATION TOP ROCK ELEVATION= TOP ROCK ELEV.= 4-5' 0 �S 2 oz Co-j LL 10' WIDTH INSTALL C-700 COCONUT FIBER BLANKETS ON BANKS - SEE CROSS SECTION 3 SEED WITH RIPARIAN MIX AND REPLANT WITH WOODY VEGETATION BOULDER CROSS VANE DETAIL NOTES: 1. BOULDER SIZE, MINIMUM 2' x 3' x 2.5'. 0 PLACE FOOTER ROCKS 1/2 OF OVERALL DIST. (TYP. BOTH SIDES) INSTALL C-700 COCONUT FIBER BLANKETS BEYOND FURTHEST DOWN STREAM 10' WIDTH ROCK ON DISTURBED BANKS SEED WITH RIPARIAN MIX AND REPLANT, WITH WOODY VEGETATION TOP ROCK ELEV X z<7. 23936 — — — EL3 239,35 EL / \ 2388E 249.67 EL EL PoM — _ _ — m85 / 238.80 1EE 12 DIP OUT \ / / \ 610E \ \ 23692 / 1E f20/PIN1067 249.68 / SANITARYMANHOLE X x \ PROPOSED CROSS VANE X; X7 /—�— // % - X —�4°s;;e 4 237.09 10 X �,e� tw cp / rtw 237.44x cpi�3a, i/�PFo�a„0 L �— 1 � 1 237./' 11 I tw > —fig( � tw / x�' 237 39 1+20 /'lv 13 ' tw / 237.75 \ \ \ \ 24011 / 237.07 / 237.77 tw hr EL / / tw cp "IX TOE tw er X 'ers Xzo e \ \ k \ \\ \ LOP pipe casing \ I \ \ 237.01 tw / ' / \ \ 40 tw X-2 236.95 — \ \ �� E \�o tw I _ _ _ — — — — _ — — — — 4a{ �4.� `r9iL I — — — — — — za 111 23TO / X X 2 TOE \ \9 44 237.71 \ _-- --- , 4 )237.68 twhr 237.0� \ tw er \ 237 tw g2 \` X z4o2\ roPE X 241. \cS' I / \ I III / I I 1 1 I ✓ \ I IIII II 1 I I C I \\ X 2EL 4830 1 / I,AV I I I I I X w.� \ \ X z<o� M W 51 kp i' ELJ66 FI RlM 21363 3135 EL 610E 312E1081 2 2313E /EE 12D/POUT IEB 12DI1 IN X zaaro \ 61073J LLJ 18 \ SqN 243,67 SANITARYMANHOLE \ \ X \ X z— MORPH DA TA SCALE 1 "=10' ------------ 243 0 10' 20' -------------- 24054 / \ TN 85209 / \ 24051 TOP1 17 / 237.65 \ / 240.5 \ \ l 1 CK BS tw X 23932 237.81� / / , V✓" / / TOEf 2 tw l TOPiI 237.83 l / / 2 \ \ / / i 237.14 tw tw at pipe 238.42 2 —23 / \ / 236.90 237.70 � / / \ t 34 tw at pipe tw / \ \ 238.34x`b 236.88 tw er 1 TOEI / \ X _ 2P 25 2382E TOP ,0 EL 12DIP of / n tw 2ko i /�(j f 240.13 X/// EL X <o // ' V �38 �3 j / 2337.81 239.29 � / / V r� \ ''A\TAT A �� R•] U I I K■ [• I11 Y• 1 ■ J toll I ��,r,err'�r■i:srr.�a �-�ss,rrri e3 �r•arrrr� n>_�� • �� aaaR��aaaa�a�w��aaaaa��aawaaa�� —��aaaary�aaaa�:ar■��aaaaaa��iaaaaaa�aaw.�� ■� ��aa■a��aaaaawa�aaaaauu■��,aaaaaaa�aa■aua�� •��aaaaar.:a■��r_aaaaaaa�aa■ara�aaarra�� of 18-inch Pipe �aaaaaa��w ■■■■■i+� ��•aaTop ��aa■a+wa•�� ua�� ■■■�c • �■■■■■rw ■��■s�a �� rr�s+aa �� aaaa■� �■■■■■w ■��■■aaaa�aa ■■■■■■�■� ■�■■■►aa a�� aaaaa�� a�.��r��aa■■r�� ■��■�� aaaaaaa�aa■ar.�aaa�a�� aaaaaaar_��:a ��aa■�a�� aaaaar•a■��aaaaaaaa�aa■■��►�� 1 �� r�� ►��aaaa�a�aaaaa�a■��aaaaaaaaaaaaaaaa�aa■a�aaau�a�� - ��aa■w�� a��aaaa�,a�aaaaar-,�■��aaaaaaa��r-�� '~�� L��r��■��aaaaaa�raaaaaaa�a�a�ar�a�� s� ��r• � �� a-�� aaaaa:� �aaaaaw� ■��■ aaaaaa�aa■ aw�aaaw a�� •■■��aaaaaa�•aaaaaaa�aa■a��i�� ■�aaaaaa�� i..■ � -��■�� .�-��■��al�aa■aaaa�aaaaa■a�aaaaaa\ ��a�aaaa�■aaaaaaa■��aa■aaaa�� ■��aa■aaaa�� • Photo 1: Limits of disturbance and silt fencing along the east side of the upstream end of the road culvert (view east). Photo taken March 22, 2023. ^✓��tip V �r Photo 2: Limits of disturbance and silt fencing along the east side of the upstream end of the road culvert (view east). Photo taken April 3, 2023.