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HomeMy WebLinkAboutPN_Project_Narrative-2018-02-12 - 1 - 18396.007 PROJECT NARRATIVE for PRELIMINARY PLAT of FOREST TERRACE Prepared by Barghausen Consulting Engineers, Inc. February 12, 2018 SITE DESCRIPTION: The subject property is located north of SR-900 on Union Avenue. The site is forested and has moderate to steep slopes. One single-family home exists on the site. Surrounding the site are residential properties to the north, west, and east. South of the site is Sierra Heights Elementary School. Union Avenue N.E. (east of the site) is classified as a Minor Arterial and currently has a 60-foot right-of-way. The western portion of the site is bisected by a regional utility corridor that includes Puget Sound Energy and Olympic Pipeline facilities, as well as a dirt roadway to access the utility corridor. PROJECT DESCRIPTION: The proposal is to subdivide the subject property into 25 residential lots. The development will be comprised of detached, single-family homes. The project is designed to have a central road (Road A) that will provide access to Lots 1 – 24; Lot 25 will have direct access from Union Avenue N.E. An additional road (Road B) is provided pursuant to the City’s requirements for neighborhood connections. One drainage facility tract (Tract A) is planned to provide detention and water quality as required. ACCESS: The proposed development will take primary access from Union Avenue N.E., a minor arterial, at its existing intersection with N.E. 27th Place. Frontage improvements will be constructed on Union Avenue N.E. along the property’s frontage. The project will construct two new public road segments which will provide direct access for the lots and present opportunities for future road connections to neighboring properties. Proposed Road A aligns with N.E. 27th Place and proposed Road B provides opportunities for future connectivity. STORMWATER: Stormwater runoff generated by the lots, Tracts A and F, Road A, and the frontage area will be routed to a detention vault. Stormwater generated by Road B and Tract B will be routed to a detention tank. The outfall from the detention tank and the detention vault discharges into a StormFilter® for basic water quality treatment. The discharge from the StormFilter® continues to a pipe system in Union Avenue N.E. which routes to a drainage swale along Union Avenue N.E., which finally connects to an existing catch basin at the intersection of Union Avenue N.E. and S.E. 95th Way. The stormwater continues within the existing drainage system outlets onto a hillside on the northern part of S.E. 95th Way, which will eventually flow to May Creek. UTILITIES: Water and sewer exist in Union Avenue N.E. An off-site sewer extension will be constructed from the project to the existing Longs Plat sewer lift station. Offsite construction will be needed for stormwater to discharge into the ditch along Union Avenue N.E. REQUIRED NARRATIVE ITEMS PROJECT NAME, SIZE, AND LOCATION OF SITE • Project Name: Forest Terrace • Gross Site Area: 13.70 acres (post BLA) • Location: 2611 Union Avenue N.E. LAND USE PERMITS REQUIRED FOR PROPOSED PROJECT - 2 - 18396.007 • Preliminary Plat • SEPA Environmental Review • Modification for Rockery/Retaining Wall Heights ZONING DESIGNATION OF THE SITE AND ADJACENT PROPERTIES • Site: R-4 • Adjacent properties: R-4 and R-6 CURRENT USE OF THE SITE AND ANY EXISTING IMPROVEMENTS The site currently contains one single-family residence. SPECIAL SITE FEATURES (i.e., WETLANDS, WATER BODIES, STEEP SLOPES) The site contains moderate slopes and is bisected by a large regional utility easement. STATEMENT ADDRESSING SOIL TYPE AND DRAINAGE CONDITIONS The King County Soils Conservation Service Soils Map for this area shown in Figure 4 of this section indicates that the on-site soils are considered Alderwood gravelly sandy loam with 8 to 15 percent slopes, Alderwood gravelly sandy loam with 0 to 8 percent slopes, Everett very gravelly sandy loam with slopes 0 to 8 percent, and Everett very gravelly sandy loam with 15 to 30 percent slopes. Stormwater runoff generated by the lots, Tracts A and F, Road A, and the frontage area will be routed to a detention vault. Stormwater generated by Road B and Tract B will be routed to a detention tank. The outfall from the detention tank and the detention vault discharges into a StormFilter® for basic water quality treatment. The discharge from the StormFilter® continues to a pipe system in Union Avenue N.E. which routes to a drainage swale along Union Avenue N.E., which finally connects to an existing catch basin at the intersection of Union Avenue N.E. and S.E. 95th Way. The stormwater continues within the existing drainage system outlets onto a hillside on the northern part of S.E. 95th Way which will eventually flow to May Creek. PROPOSED USE OF THE PROPERTY AND SCOPE OF THE PROPOSED DEVELOPMENT The Forest Terrace project is a single-family residential project consisting of the development of a forested area generally located between Union Avenue N.E. to the east, single-family homes to the north and west, and Sierra Heights Elementary School to the south. The proposed project is to construct 25 single-family lots with associated roads, utilities, and stormwater facilities. FOR PLATS, INDICATE THE PROPOSED NUMBER, NET DENSITY, AND RANGE OF SIZES (NET LOT AREA) OF THE NEW LOTS The project will contain 25 lots for detached single-family residences. The lots range in area from 9,038 square feet to 19,584 square feet, with an average area of 10,281 square feet. The net lot area is 11.68 acres (508,657 square feet). Net density of the project is 2.14 dwelling units per net acre (du/acre). Each lot contains a minimum of 250-square feet of private open space in their rear yards. Approximately 5.03 acres (219,134 square feet) of common open space will be provided for the residents in Tracts B, C, D, and E. ACCESS - 3 - 18396.007 The project will construct two new public road segments, Roads A and B, which will provide direct access for the lots and present opportunities for future road connections to neighboring properties. Frontage improvements will be constructed on Union Avenue N.E. along the property’s frontage. PROPOSED OFF-SITE IMPROVEMENTS (i.e., INSTALLATION OF SIDEWALKS, FIRE HYDRANTS, SEWER MAIN, ETC.) Off-site sanitary sewer and stormwater mains will be constructed with the project’s development. Frontage improvements, including sidewalks, street trees, street lighting, and pavement widening will occur on Union Avenue N.E. along the property’s frontage. TOTAL ESTIMATED CONSTRUCTION COST AND ESTIMATED FAIR MARKET VALUE OF THE PROPOSED PROJECT The construction costs and fair market value are to be determined. ESTIMATED QUANTITIES AND TYPE OF MATERIALS INVOLVED IF ANY FILL OR EXCAVATION IS PROPOSED Approximately 190,000 cubic yards of total grading will be necessary for the project. Approximately 30,000 cubic yards of fill will be needed (see Preliminary Grading Plan). At this time, the source of fill material is unknown; that information will be provided as required as part of the grading and construction permit process. The amount of and destination for exported material is unknown at this time. NUMBER, TYPE, AND SIZE OF ANY TREES TO BE REMOVED The site contains 1,024 trees including hemlock, fir, cedar, and maple. The project is currently designed to retain 119 viable evergreen and deciduous trees (maple) in the development area (see the Arborist Report and the Preliminary Tree Replacement and Landscape Plans). The project is currently designed to replant approximately 568 trees (423 in open space tracts, 73 street trees, and 72 yard/buffer trees – see Landscape Plans L-1 – L-3). EXPLANATION OF ANY LAND TO BE DEDICATED TO THE CITY The project will dedicate 10.5 feet of right-of-way at Union Avenue N.E. per the Minor Arterial street standard. ANY PROPOSED JOB SHACKS, SALES TRAILERS, AND/OR MODEL HOMES To be determined.