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HomeMy WebLinkAboutNARRATIVE - 23-00085 - Founders Square Phase 3 - Plat THE DYER GROUP, LLC • 343 E 4th NORTH, SUITE 108 • REXBURG, ID 83440 - 6001 208.390.9700 (VOICE AND TEXT) • wdyer@thedyergroup.com PROJECT NARRATIVE for FOUNDER’S SQUARE PHASE 3 December 2022 SUBDIVISION DESCRIPTION Founder’s Square is a planned unit subdivision development situated southeasterly of South Second East and Sunrise Drive in southeast Rexburg, Idaho. The development was master planned and approved several years ago as a planned unit development, and is being constructed in phases. The subdivision property is within the City of Rexburg and thus is subject to development in accordance with the zoning and subdivision development requirements of the City; and is served by the City’s existing water, sewer, and storm drain systems installed under Phase 1. This project is the third phase of development, consisting of a 4.6-acre parcel subdivided into 15 single family home lots in the northeast corner of the master planned Founder’s Square subdivision area. The 15 single-family lots represent an eventual population of approximately 51 persons when fully developed and occupied. The City of Rexburg has approved the planned unit development and has indicated construction of the subdivision may move forward subject to the terms and conditions contained in an executed development agreement. This new subdivision phase will be served with 44 ft. wide public paved streets with curb and gutter; and public water, sewer, and storm drain utilities. This project comprises the work necessary to install the infrastructure serving the development, including tying into, and utilizing some existing water and sewer piping that was installed several years ago with Phase 1 – which is already connected to and served by existing City systems. Work includes construction of the sewer, water, and storm drain facilities (curb and gutter leading to existing catch basins on an existing storm drain system); followed by construction of the paved streets with curb and gutter. Street lighting and any landscaping will be provided by others. CONTACTS Following is a list of entities involved in developing this project, together with appropriate contact information. Name: Founder’s Square Planned Unit Development, Phase 3 Owner: Sephlin and Daric Hepworth 208-757-8888 407 South 3rd East sephlindaric@icloud.com Rexburg, ID 83440 Developer: - Same as Owner - 2 Engineer: Winston R. Dyer, PE 208-390-9700 The Dyer Group, LLC wdyer@thedyergroup.com 343 E 4th North, Suite 108 Rexburg, ID 83440 City: Keith Davidson, City Engineer 208-372-2320 City of Rexburg, Idaho Keith.Davidson@rexburg.org 35 N 1st East Rexburg, ID 83440 PROJECT DESCRIPTION This project is intended to install the necessary water, sewer, and street facilities to serve the above-described third phase of the subdivision. Water and sewer service has been made available by previous connection to existing City systems in Phase 1 of the subdivision constructed in 2008. Storm drainage will be provided by connecting the new curb and gutter to existing catch basins on a storm drain system that was also constructed in Phase 1. The project plans are shown in color and use different colors to differentiate between existing and new proposed water and sewer lines to be constructed. The City previously reviewed the development proposal for the entire subdivision and determined that it has the facilities and capacities to serve the subdivision with city water, sewer, and storm drain service. Attached is the “Will Serve” letter for the subdivision for “all phases”, which is still valid. SEWER SERVICE The plan for sewer service within the subdivision is to construct a gravity collection system collecting wastewater and conveying it around the street loop to connect into a sewer main stubbed out into this Phase area during Phase 1 of the subdivision development several years ago that is now accepted as part of the City wastewater collection system. Wastewater is conveyed through the existing City collection and conveyance systems to eventual treatment at the Rexburg wastewater treatment plant. Groundwater is not a problem in this area and basements are expected for the homes to be built. The depth of the proposed sewer is approximately 8-11 ft. which will provide adequate depth for serving the development. The sewer collection system is proposed to be constructed with 8” ASTM 3034 PVC sewer pipe. The use of PVC pipe with its smoother flow characteristics allows using a minimum grade of 0.32% for the pipeline slope to better fit the terrain, similar to what has already been done in previous phases of the subdivision. This results in a velocity of 2.0 FPS in a half-full pipe and 2.6 FPS in a full pipe. Rexburg has several areas where pipe has been installed at this slope and it has not been a maintenance concern. The City has its own sewer cleaning equipment and personnel to clean the sewer lines when needed. 4” sewer service lines will be stubbed into the individual lots with proper separation from the water services. Sewer service was previously installed into the southeasterly lot in Phase 1. 3 As noted, wastewater will be conveyed from the subdivision through Rexburg’s existing wastewater collection system, and treatment will be provided at Rexburg’s existing wastewater treatment plant. WATER SERVICE Water service is available to this phase of the subdivision through a water distribution system constructed in Phase 1 which will provide for both culinary demand and firefighting capability. The waterline to serve this Phase will be installed in a looped configuration connecting to existing water lines installed in Phase 1 to provide appropriate distribution to this Phase 3 development. The water distribution system is designed to maintain system pressure and deliver adequate culinary water service and fire flow for the development. A fire hydrant will be installed in the northeast corner of the subdivision to continue and match the fire hydrant grid installed during Phase 1. The water distribution piping will be constructed of 8” cement mortar lined ductile iron piping as per Rexburg standards. Gate valves have been provided at the stub outs from the existing Phase 1 piping to facilitate connection and properly isolate the water piping in this Phase 3. The proposed water and sewer mains do not cross, and appropriate horizontal separation between them has been designed to meet DEQs standards. 1” PE water service lines will be stubbed into the individual lots to provide water service. The lines will be stubbed into the lots a sufficient distance to pass under the dry utility easement and avoid future disturbance. Meter boxes and water meters will be installed on the individual service lines at a later point when property owners will build their home and need water service. Homeowners will purchase and install water meters and pay connection fees when they arrange to receive water service to their property. The water demand for this Phase 3 of development is within available capacity. Connection fees will help provide for additional capacity in future system upgrading. STORM DRAINAGE Storm drainage for this Phase of the subdivision will be accomplished by collecting surface runoff from the right-of-way area in a curb and gutter system which flows to storm drain catch basins previously installed in Phase 1. Those catch basins are on an existing storm drain system for the overall subdivision, which was master-planned and designed to accommodate this Phase 3 when constructed. Established covenants for development of individual properties in the subdivision contain the requirement that all runoff on the property must be retained on-site. STREETS Street design and construction for the subdivision will follow City of Rexburg standards for right- of-way width (68’), alignment and grading, typical section (44‘ width), and surfacing section thicknesses. Geotextile separator fabric will be placed on the roadway subgrade to preclude fine- grained silt soils from infiltrating the roadway base gravels. Plant mix paving will be used for the roadway surface after placement of adequate base gravels. 4 6” high back concrete curb and gutter in accordance with the Rexburg standard will be constructed, and individual properties will cut-in driveway accesses in the curb when the location of their driveway becomes known and is constructed. A 7 ft. landscaped area is located behind the curb and then a 5-foot sidewalk will be installed in front of the right-of-way line when home construction is complete (to avoid damage during home construction). Maximum longitudinal street grade is 2.42%, and cross grade will be a 2% tangent crown. PLANS AND SPECIFICATIONS Plans and specifications for development of the utility systems and roadways within this proposed subdivision have been designed and prepared by The Dyer Group, LLC under the responsible charge of Winston R. Dyer, PE (Idaho No. 4315). They are being submitted with this project narrative for formal review and approval by DEQ and the City. Since there are to be both existing and new water and sewer pipelines, and for clarity, the plans are being presented in color with different colors to differentiate both water and sewer, and also existing and new pipelines. The specifications follow the Idaho Standards for Public Works Construction, latest edition. Special Provisions have been written to provide additional information on clarifying which Standard Specifications and which Standard Drawings apply to the project, together with additional detail or clarification as appropriate for application of those standards to this project. The Special Provisions also contain administrative provisions for the contractor to follow in the work, which includes the requirement to implement and follow a Stormwater Pollution Prevention Plan (SWPPP) during construction of the project. The design engineer will be providing construction observation to assure all improvements are constructed in accordance with the approved plans and specifications. GENERAL, WATER, AND SEWER CHECKLISTS Standard DEQ checklists for review of water and sewer plans associated with this proposed subdivision are also being furnished with this submittal to provide appropriate information. – End of Project Narrative – attach: Vicinity Map “Will Serve” Letter from Rexburg