MAGNOLIA SPRINGS SUBDIVISION, PHASE ONE Engineering Comments: Must comply with the Mobile County Flood Damage Prevention Ordinance. Development shall be designed to comply with the storm water detention and drainage facility requirements of the City of Mobile storm water and flood control ordinances, and requiring submission of certification from a licensed engineer certifying that the design complies with the storm water detention and drainage facility requirements of the City of Mobile storm water and flood control ordinances prior to the issuance of any permits. Fire-Rescue Department Comments: Subdivision layout and design must comply with the requirements of the 2003 International Fire Code, including Appendices B through D, as adopted by the City of Mobile. Commercial buildings and sites within the City of Mobile Fire Jurisdiction must comply with the requirements of the 2003 International Fire Code, including Appendices B through D, as adopted by the City of Mobile, and the 2003 International Existing Building Code, as appropriate. MAWSS Comments: MAWSS has water and sewer services available, but a Capacity Assurance application for sewer service has not been applied for. MAWSS cannot guarantee sewer service until the Capacity application is approved by Volkert Engineering, Inc. The plat illustrates the proposed 176-lot, 87.8 + acre subdivision, which is located on the North side of Silver Pine Road at its West terminus. The applicant states that the site is served by public water and sanitary facilities. This application was preceded by 5 other applications for the same site, and represents a 1-lot increase over the most recent Planning Commission approved Phase One application from November 15, 2007. A condition of approval of the overall 440 + acre, 948 lot subdivision from the April 19, 2007 meeting of the Planning Commission was that each individual phase would be submitted to the Planning Commission for review. While a previous Phase One application was approved, changes to the number of lots necessitate this new application. The layout of the revised Phase One essentially corresponds to that depicted within the overall subdivision, however, a common area is being eliminated to allow for an additional lot. It should be pointed out that all approvals for development of the site (overall and Phase One) will have expired by the November 20, 2008 meeting of the Planning Commission, and the Subdivision Regulations have been changed to address watershed protection concerns for sites such as this one located within the J. B. Converse watershed. Therefore, submission of an application for the overall subdivision is recommended, and if approved, applications for extensions should be filed every year until a phase has been recorded, or an extension request is denied. The Phase One site has frontage onto Silver Pine Road, a proposed major street. The plat depicts dedication of right-of-way sufficient to provide a minimum of 50-feet from the centerline of Silver Pine Road where it is a proposed major street, and additionally dedicates 30-feet from the - 1 -
projected non-major street centerline of Silver Pine Road so that it can be extended as a minor street along the southern boundary of the site. New road construction is proposed. Any new roads for the site must be constructed to meet County Engineering standards and be dedicated to Mobile County for maintenance. Several streets within the proposed Phase One development appear to have long straight sections, thus traffic calming devices may be required. Additionally, all lots should be limited to one curb-cut each, with the size, design and location to be approved by County Engineering, and should be denied direct access to Silver Pine Road. All lots proposed within Phase One will meet the minimum area requirements for lots with public water and sanitary sewer (7,200 square feet), and only a few lots (approximately 10) will have just less than 60-feet of frontage on a public street. All lots are labeled with their size in square feet, and the 25-foot setback line is depicted on the plat, as is a note indicating the required front minimum building setback. Six common areas containing a total of 26.2 + acres are depicted on the plat. Most of the common areas will be at least partially used for storm water detention, however, some common areas contain wetlands and floodplains associated with a branch of Hamilton Creek, while others contain Alabama Power easements. The common areas are labeled, and there is a note on the plat (page 2) stating that maintenance of all common areas is the responsibility of the property owners (association). This site is located in Mobile County, and a note is on the plat stating that any lots which are developed commercially (or multi-family residential) and adjoin residentially developed property must provide a buffer, in compliance with Section V.A.7. of the Subdivision Regulations, as required. The site is located within the J.B. Converse watershed, the primary drinking water supply for the Mobile Area Water and Sewer System. The Subdivision Regulations were recently amended (Section V.A.5.) to at minimum match Mobile County standards for development within the watershed, thus the site must be designed so that no field lines or septic tanks are constructed or maintained within a flood prone area as designated by FEMA, or within a Buffer Zone as defined in Section II, Definitions. Furthermore, within the watershed, storm water detention facilities are required in any Subdivision. Detention areas must be designed to provide a minimum detention capacity to accommodate the volume of a 50 year post development storm, with a maximum release rate equivalent to the 10 year storm pre-development rate. A licensed Professional Engineer must certify, prior to the recording of the final plat, that the design of the Subdivision and its storm water detention features are designed in accord with these requirements. Any storm water detention facility must be shown in the plans and on the recorded subdivision plat as a common area not maintained by the City of Mobile, Mobile County or the State of Alabama All Subdivisions shall use Best Management Practices for water quality protection as identified in The Use of Best Management Practices (BMPs) in Urban Watersheds EPA, per - 2 -
the requirements of Section V.A.5. of the Subdivision Regulations (amended September 18, 2008). The geographic area defined by the city of Mobile and its planning jurisdiction, may contain Federally-listed threatened or endangered species as well as protected non-game species. Development within the Planning Jurisdiction must be undertaken in compliance with all local, state and Federal regulations regarding endangered, threatened or otherwise protected species. As previously mentioned, the site contains wetlands and floodplains associated with Hamilton Creek, and therefore the site may be environmentally sensitive. Approval of all applicable federal, state and local agencies will be required prior to the issuance of any permits or land disturbance activities. Another issue that has become a recent concern of the Commission is that of access and traffic. While the composite for Magnolia Springs did not provide, nor did the Commission require a Traffic Impact Study, recent developments around the site and within the Planning Jurisdiction have brought the issue of traffic and the impact of new, large subdivisions to the forefront. Given the total number of lots in the subdivision, and the limited access points, the provision of a Traffic Impact Study based on the entire composite development would be appropriate with the submission of a new application for the overall development. Based upon the preceding, it is recommended that the application be Heldover until December 18 th, so that the following items can be addressed, with revisions due by December 8 th : 1) Submission of an application for the overall Magnolia Springs development by the December 8 th application deadline, that reflects amendments to the Subdivision Regulations and that includes two copies of a Traffic Impact Study; 2) Revision of the Phase One application to provide storm water detention that reflects amendments to Section V.A.5. of the Subdivision Regulations, or certification by a licensed engineer via a note on the plat or a letter submitted prior to the signing of the plat stating that the storm water detention complies with Section V.A.5. of the Subdivision Regulations (if changes to the physical layout of the subdivision will not be required to provide the required detention); 3) Placement of a note on the plat stating that all lots, are denied direct access to Silver Pine Road and are limited to one curb cut, with the size, design and location to be determined by County Engineering; 4) Placement of a note on the plat stating that any lots which are developed commercially (or multi-family residential) and adjoin residentially developed property must provide a buffer, in compliance with Section V.A.7. of the Subdivision Regulations; and 5) Redesign of the subdivision, if necessary, to comply with the requirements of the 2003 International Fire Code, including Appendices B through D, as adopted by the City of Mobile, particularly as applied to the subdivision layout, design and road construction, to be verified by Mobile Fire-Rescue. - 3 -
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