The URL can be used to link to this page

Home My WebLink About20081362 Ver 1_More Info Received_20080919` r ENVIRONMENTAL SERVICES, INC 524 S NEW HOPE ROAD RALEIGH NORTH CAROLINA 27610 919-212-1760 • FAX 919-212-1707 www envlronmentalservlcesmc com September 16, 2008 Ms Coleen Sullins NCDWQ - Transportation Permitting Unit 1650 Mail Service Center Raleigh, NC 27699-1650 Re City of Raleigh Application DWQ# 20081362 Ms Sullins S`p y r- Jri?u 0S 15 6- ?`- ESI is submitting this information on behalf of the City of Raleigh for the Fayetteville Street/Penmarc Drive/Summit Avenue project located in Wake County This additional information is in response to your letter dated 8 September 2008 I ) Please include a site plan and stormwater plan for the project The City of Raleigh has provided the attached site plans and stormwater plans per your request 2 ) Please describe how buffer impacts occur at site B3, but no stream impacts occur The project stoops short of crossing the bridge of Rocky Branch Buffer impacts are proposed in this location, however they result from mainly the improvements proposed to the existing storm drainage outfall in this location and minor fill slope impacts involved with the roadway widening within this location The road does continue across Rocky Branch in a perpendicular manner, however the stream itself is outside of the project area No improvements are proposed in relation to the existing bridge 3 ) Buffer impacts at site B2 and BI appear to be not from a road crossing, and therefore will require mitigation These two impacts areas (BI & 132) result from fill slope impacts, but not a direct crossing of a stream channel Therefore, the applicant is requesting that EEP allow in-lieu fee payment for these unavoidable impacts to Zone 2 (656 ft2) If accepted by EEP, a copy of the acceptance letter will be forward to DWQ 4 ) Please explain how the impacts at site W11Bl could not be avoided and/or further minimized The City has provided the attached narrative of the project's proposed improvements The narrative addresses your request Please do not hesitate to call me if you have any questions or additional comments Thank you for your assistance with this project Sincerely, Environmental Services, Inc #xi,4 Jeff Harbour, PWS FLORIDA 0 GEORGIA 0 NORTH CAROLINA • SOUTH CAROLINA • MARYLAND 0 OHIO Fayetteville Street Widening from Wilmington Street to Bragg Street Penmarc Drive/Water Works Street Extension from Green Street to Fayetteville Street Summit Avenue Improvements from Gilbert Avenue to Proposed Water Works Street Purpose and Need The project will upgrade Fayetteville Street to current city standards and will offer an alternative route to the existing residential street system by extending Penmarc Drive/Water Works Street to Fayetteville Street, providing improved circulation of local traffic within the project's general location Fayetteville Street is classified as a Collector Street on the City's Thoroughfare System Plan Penmarc Drive is considered a Commercial Street General Description Fayetteville Street exists as a two lane ribbon paved roadway from Wilmington Street to the bridge over Rocky Branch Creek Its Collector Street classification indicates it could be ultimately widened to a 41-foot back-of-cub to back-of-curb roadway section at some point in the future Its widening is proposed from Wilmington Street to the southern end of the bridge The proposed road will have three 12-foot wide lanes with curb, gutter and sidewalk on one side to mostly accommodate commercial as well as pedestrian traffic from Wilmington Street to its proposed intersection with Water Works Street From proposed Water Works Street to the bridge, the proposed road will have two 14-foot wide lanes with curb and gutter as well as pedestrian accommodation on one side This section of Fayetteville Street will closely match its existing section north of the bridge over Rocky Branch Creek Traffic calming measures will also be constructed along the section of Fayetteville Street south of the bridge Penmarc Drive exists as a Commercial Street having a typical section capable of accommodating three 12-foot wide lanes with curb and gutter The width of the existing roadway measures 41 feet from back-of-curb to back-of-curb The road is proposed to be realigned from Green Street and extended as Water Works Street to Fayetteville Street with curb and gutter as well as sidewalk on one side Summit Avenue exists as a gravel residential street The street is proposed to be paved to residential street standards It will have two 13-foot wide lanes with curb and gutter as well as sidewalk on one side Erosion Control Erosion Control during construction operations will be handled by sediment traps, temporary diversion ditches, silt fences and inlet protection All erosion control measures are designed in accordance with criteria established by the North Carolina Department of Environmental Health and Natural Resources Storm Water Design Methodology For each individual storm water inlet, a drainage area was measured Each area's impervious surface percentage was determined and a rational "C" factor was calculated The data was later used in the pipe sizing calculations The pipes were sized using Geopak Drainage This program accepts the input data from each inlet as well as the physical characteristics of the storm system to be designed and calculates flow rates and pipe sizes throughout the system For rainfall data, the IDF (Intensity-Duration-Frequency) curve for the 10-year storm event describing the Raleigh-Durham region was used The final results of this program showing the calculated pipe sizes and hydraulic grade lines are included in the report The minimum pipe diameter used for this project is 15 inches The majority of the pipes are RCP with the exception of one temporary culvert used across Penmarc Drive/Water Works Street which is proposed to be a corrugated plastic pipe and will be used to accommodate crossing a draw during construction Velocity dissipaters were designed for each outlet to prevent erosion and scour in these areas The dissipaters were designed to be NC DOT Class I or B rip rap depending on the pipe size The rip rap pad dimensions are based on NC DOT standards for outlet protection The velocity dissipaters are permanent features of the storm drainage system Water Works Street Wetland/Buffer Impacts Ml/B11 The horizontal and vertical alignments of Water Works Street were established within two physical constraints One was a mayor transmission power substation and associated transmission pole/line facilities owne and operate y rogress Energy Carolinas (PEC) located along the north side of the proposed street The other was a head water jurisdictional wetland as well as its associated jurisdictional surface water (stream channel) and Neuse River Riparian Buffer located along the south side of proposed Water Works Street and opposing side of the substation Impacts to the wetland, stream and buffer areas were greatly minimized by shifting the horizontal alignment as far north and lowering the vertical alignment as much as the substation's above ground and underground transmission structures would allow The substation is situated approximately 20 feet above the proposed roadway elevation Its above ground transmission structures are ultimately secured along the substation's southern section (north of proposed Water Works Street) by a fence located at the same approximate height Establishing the alignment as far north and 2 as low as possible mimmized the fill-slope impacts to the wetland and buffer areas but maxinuzed the cut-slope areas along the substation The cut-slope limits initially fell as close as 3 to 8 feet from the station's fence structure PEC informed the City of their mayor underground transmission structures existing south of this fenced area and mandated the slope limits fall no closer than 15 feet from the fence Given PEC's mandate and in order not to impact more of the wetland and buffer areas than proposed with the initial alignments, a 6-foot maximum height retaining wall was designed along the substation side of the proposed street The proposed retaining structure enabled the cut-slope limits of our proposed street to be shifted to the required 15-foot offset distance from the fence as well as enabled the proposed street's initial fill-slope impacts on the wetland/buffer areas to be maintained (not increased)