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Home My WebLink About20190262 Ver 2_PCN Supplemental Information_202007271 Timmons Group Burgess Court Supplemental Information, PCN Application PCN Supplemental Information SECTION A – APPLICANT INFORMATION PART 3. OWNER INFORMATION SECTION B – PROJECT INFORMATION AND PRIOR PROJECT HISTORY PART 1. PROPERTY IDENTIFICATION 3a. Names on Recorded Deed 3b. Deed Book and Page Number 3d. Street Address 3e. City, State, Zip 1a. Property Identification Number (PIN) HUNTERS CREEK TOWNHOUSE HOMEOWNERS ASSOCIATION, INC DB 3506 PG 174 C/O SENTRY MANAGEMENT, INC. 2180 W. STATE ROAD 434, STE 5000 LONGWOOD, FL 32779 0793176867 HUNTERS CREEK TOWNHOUSE HOMEOWNERS ASSOCIATION, INC DB 3646 PG 391 C/O SENTRY MANAGEMENT, INC. 2180 W. STATE ROAD 434, STE 5000 LONGWOOD, FL 32779 0793172961 NEERAJ KUMAR DB 11891 PG 1101 1713 KAYLA COURT RALEIGH, NC 27606 0793175856 GLENN AND KIM MILLER DB 17315 PG 462 5308 BURNING OAK COURT RALEIGH, NC 27606 0793175859 JON DAVID JIVIDEN, EMILY ANN NANCE DB 13872 PG 220 1709 KAYLA COURT RALEIGH, NC 27606 0793175960 JEREMIAH CORKERY, FIONA FARRELL DB 13277 PG 437 4709 TWINWOOD COURT RALEIGH, NC 27613 0793175943 MARY G PARKER DB 3875 PG 136 1705 KAYLA COURT RALEIGH, NC 27606 0793175945 RONALD HAL JOHNSON DB 08-E PG 3050 1703 KAYLA COURT RALEIGH, NC 27606 0793175927 JACKIE JOHNSON, BRANDON GIBBS HAWKINS DB 15283 PG 1937 1701 KAYLA COURT RALEIGH, NC 27606 0793175939 2 Timmons Group Burgess Court Supplemental Information, PCN Application SECTION B – PROJECT INFORMATION AND PRIOR PROJECT HISTORY PART 3. PROJECT DESCRIPTION 3a. Project Description: This PCN Application is for an amendment to existing 404 and 401 permits. The permits are listed as follows: USACE 404 No: SAW-2019-00471 Approval Date: 4/18/2019 DWR 401 and Buffer Authorization: DWR NO 19-0262 Approval Date 3/3/2019 These documents have been included in Appendix B. The PCN Application was originally sent in by Kris Bass Engineering as the Applicant. The HOA requested assistance through the City of Raleigh Drainage Assistance Program. Due to the culvert failure at Burgess Court the project was accepted into that program. The project prepared by Kris Bass Engineering was designed with two reaches. Reach one consisted of a stream restoration on approximately 150 linear feet of stream. Reach two consisted of bank repairs along 75 linear feet of stream adjacent to the Burgess Street Culverts. The PCN application was approved for this work in 2019 as listed above. The Burgess Street Culvert flared end sections were dislodged during a storm event which caused blockage and severe erosion on the banks and adjacent to the dual 84-inch CMP’s. A stress fracture in the street was also found indicating potential street failure in the future. A part of the City’s Drainage Assistance program addresses failing city infrastructure and therefore Reach 2 previously permitted with the original 401 and 404 permits was re-designed by the Timmons Group to permanently stabilize the Pipe entrance and protect the street downstream infrastructure. The new design for Reach 2 includes the replacement of the dual 84-inch flared end sections with a head wall structure. The headwall structure has been designed to be within the footprint of the existing flared end sections so that no additional stream impacts to the overall stream length will occur with the placement of the headwall. The stream had migrated severely to the west and a large point bar had established restricting flow to the eastern culvert. With the re-design of Reach 2, the stream configuration has been improved to provide a better alignment to the dual culverts through an improved radius of curvature. The stream banks will be stabilized with a rock toe along a short section in the approach to the culverts. The existing riffle just downstream of the existing sanitary sewer crossing will be extended, pool improvements made, and an embedded stone apron has been designed just upstream of the proposed headwall. Reach 2 has been completely re-designed as shown in the attached construction plans. The original design of Reach 1 proposed by Kriss Bass Engineering remains as originally intended with slight modifications to the placement of some of the rock structures to move them further out of the existing sanitary sewer easement required by the City’s utility department. The original application by Kriss Bass Engineering did not include the temporary impacts to zone 2 for the buffers due to the construction access. Therefore this is the primary change to the overall impacts for Reach 1 included herein. The project site is located within the Hunters Creek townhouse development in Raleigh, North Carolina. An unnamed tributary (UT) to Bushy Creek runs through the Homeowners Association property area behind the townhouses along Kayla Court and Ithaca Lane. The watershed contributing stormwater to the 3 Timmons Group Burgess Court Supplemental Information, PCN Application project site was evaluated using USGS StreamStats online application. The contributing watershed has an area of approximately 0.37 square miles. 3b. List total estimated acreage of all existing wetlands of the property: The project will be completed in a limited area of the project. No wetlands were iden tified within the project area. The repair area along the stream is the same length covered in the original permit. 3d. Explain the Purpose of the Project: The primary objective for the project is to repair failing Dual 84-inch pipes at Burgess Court. Burgess court is the only entrance to a multifamily development and therefore permanent stabilization of the pipe infrastructure is paramount. Because both repairs to Reach 1 and Reach 2 was approved through the City of Raleigh Drainage Assistance Program the work in Reach 1 is proposed to be constructed with the much- needed repairs to the culverts in Reach 2. 3e. Describe the Overall Project in Detail, Including the Type of Equipment to be Used: Reach 1: The improvement of the stream at this location is a full stream restoration, involving the construction of grade control structures, the excavation of a new channel that reconnects the stream to a floodplain, backfilling of the old channel, and thorough planting of native species that will strengthen the streambanks and provide wildlife habitat. The stream thalweg will be repositioned slightly to move the stream further away from nearby townhomes, but the stream length will remain unchanged. To accomplish this, the left bank, as looking downstream, will be cut back, while the right bank will be backfilled. In-stream grade control structures in this reach include: 2 Boulder Drop Pools, 1 Double Cross Vane, 2 Constructed Reinforced Riffles, and 2 Boulder Steps. Additional buffer impacts will occur temporarily along the construction access and staging area. These areas will be stabilized with proper riparian vegetation at the conclusion of construction. All side slopes are 3:1 or greater, except for the last 25 LF of the reach on the right bank, where the steepest side slope is approximately 1.5:1. All stream and buffer impacts are detailed in the tables below. Reach 2: The proposed headwall and culvert improvements will be installed where the old pipes were previously located so that there are no impacts to the stream associated with pipe installation. The improvements to the stream at this location include channel and bank grading and stabilization, culvert improvements, and headwall installation. The stream position will be adjusted slightly at the culvert entrance to provide a more appropriate radius of curvature. The left bank, as looking downstream, will be cut back while the right bank will be filled to shift the stream east by approximately 15 feet. The channel will be transitioned in width as to accommodate the existing dual 84-inch culverts. Stream stabilization will be provided on the banks through reconstruction to a side slope of 2H:1V with rock toe reinforcement, installation of constructed riffle that ties into the existing rock, and planting of permanent woody vegetation. The existing sanitary sewer manhole on the east side of the stream will be stabilized using a rock toe. The existing flared end sections will be removed. (The City completed the emergency removal of the dislodged obstructions in January 2020). A 10-foot section of pipe and headwall will replace the flared end section within the existing culvert impact length. It was determined through soils investigations that the fill soil behind the culverts was less than optimal, therefore structural fill will be brought in for placement behind the new headwall structures (Falcon Engineering soils reports are available upon request). The fill slope from the road to the headwall will be established at a maximum slope of 3H:1V. 4 Timmons Group Burgess Court Supplemental Information, PCN Application Existing scour has occurred along the length of the pipe to distances as great as 10 feet. These scour areas will be filled with grout. The stream bank corridor within the repair area will be re-vegetated along both sides of the stream along with the bankfull bench. The re-introduction of vegetation to the graded channel banks will aid in providing long term bank stability. The vegetation will be a combination of native herbaceous and woody plant species. The stabilized banks and re-vegetated corridor will additionally provide stormwater quality benefits. The equipment to be used in the project is earth moving equipment and various othe r support apparatuses. The stream normal flow will be pumped around the project site. Stabilization will occur daily within the work area. Heavy equipment may include hydraulic excavator, compactors, bulldozers, skidsteer loaders, and dump trucks to load and unload materials. The construction equipment will enter Reach 1 from the parking area on Sterlingworth Drive. The construction equipment will enter Reach 2 from Burgess Court. All construction will be performed within a defined limit of disturbance. 5b. Project History USACE 404 No: SAW-2019-00471; Application Date: 2/25/2019; Approval Date: 4/18/2019 DWR 401 and Buffer Authorization: DWR NO 19-0262; Application Date: 2/25/2019 Approval Date 3/3/2019 SECTION C – PROPOSED IMPACTS INVENTORY 3i. Stream Impacts: S1: The permanent impact with no functional loss are associated with stabilization of the stream include bank grading, boulder steps, rock vane, a constructed riffle, and installation of permanent woody vegetation for approximately 150 LF of stream in Reach 1. S2: The permanent impacts associated with rock toe include undercutting the bank to provide room to place the rock toe for approximately 58 LF of stream in Reach 2. S3: The permanent impacts associated embedded apron upstream of culvert inlet is 12 LF in reach 2. S4: The permanent impacts associated with culvert extension and headwall is 10 LF in reach 2. 5 Timmons Group Burgess Court Supplemental Information, PCN Application Table 1 – Stream Impacts Chart Impact Permanent / Temporary Type of Impact From PCN by KB Engineering 2019 PCN Amendment 2020 Reach 1 Reach 2 Reach 1 Reach 2 S1 Permanent Stabilization 150 75 150 0 S2 Permanent Rock Toe 0 0 0 58 S3 Permanent Riprap Apron 0 0 0 12 S4 Permanent Pipe Extension and headwall 0 0 0 10 Total Length Permitted in 2019 225 Total Length Impacted in 2020 230 Total Change in Impacted Length 2020 5 6i. Buffer Impacts: B1: The buffer impacts associated with stabilization of the stream include grading to provide a floodplain bench along the stream for approximately 3743 square feet for Reach 1 and to improve the overbank side slopes for approximately 1147 square feet for Reach 2. All of B1 impacts occur in Buffer Zone 1. The total 4890 square feet of impacts have been previously permitted. B2: The buffer impacts associated with the construction access include clearing to provide sufficient room for construction activities to occur. Approximately 833 square feet of Buffer Zone 1 and 615 square feet of Buffer Zone 2 for Reach 1 are included in the impacts. Approximately 2763 square feet of Buffer Zone 1 and 2780 square feet of Buffer Zone 2 for Reach 2 are included in the impacts. The total 3596 square feet of Buffer Zone 1 and 3395 square feet of Buffer Zone 2 are additional impacts for which this amendment required. Table 2 – Buffer Impacts Chart Impact Permanent / Temporary Type of Impact From PCN by KB Engineering 2019 PCN Amendment 2020 Reach 1 Reach 2 Reach 1 Reach 2 Z1 Z2 Z1 Z2 Z1 Z2 Z1 Z2 B1 Temporary Stabilization 3743 0 1147 0 3743 0 1147 0 B2 Temporary Construction Access N/A N/A N/A N/A 833 615 2763 2780 Total Area Permitted in 2019 3743 0 1147 0 Total Area Impacted in 2020 4576 615 3910 2780 Total Change in Impacted Area 2020 833 615 2763 2780 SECTION D – IMPACT JUSTIFICATION AND MITIGATION 6 Timmons Group Burgess Court Supplemental Information, PCN Application 1a. Specifically describe measures taken to avoid or minimize the proposed impacts in designing project. This project is necessary due to the active bank erosion that is encroaching dangerously on the residential structures at in the Hunters Creek townhouse development as well as to repair the damaged culvert entrance at Burgess Court. The project will stabilize the stream channel and to eliminate active erosion of the stream channel bank. The stabilization of the banks will reduce sediment import into the stream that is currently occurring. The minimization of the project includes working with the existing stream pattern with limited pattern changes and raising the channel for better floodplain connection to reduce the stress on the stream banks during large storm events. The limits of disturbance have been minimized to only the area needed to construct the repairs. Impacts to the stream buffer will be minimized by accessing the site through a narrow corridor and protection of as much existing vegetation as possible. 1b. Specifically describe measures taken to avoid or minimize the proposed impacts through construction techniques. Pumping of normal stream flow be maintained and pumped around the site during construction activities. Bank stabilization, covering the slope with riparian seed and coir matting, will occur daily upon completion of bank grading. Permanent woody vegetation will be installed on all stream banks above rock toes limited to bankfull elevations. SECTION F – SUPPLEMENTARY INFORMATION 5d. What data sources did you use to determine whether your site would impact Endangered Species or Designated Critical Habitat? The site is an existing urban residential area that has been previously impacted by development. Open areas are currently being mowed and maintained. Habitat is not present for Wake County listed vertebrate and invertebrate endangered species with the exception of Northern Long Eared Bats. It is not anticipated that this tree removal would be an impact to critical habitat for the Northern Long Eared Bat in Wake County. Therefore, it is not anticipated that there will be any adverse impacts associated with T/E species.