Atlas Tranquility Park Development Waiver Requests

Original title: Atlas Tranquility Park - Improvement Plan 000635 - Waiver to Improvement Plan in Review Parcel #: 39279-026-00 # WaiverPIR-000859-2026 Tillman & Associates Engineering, LLC LDC 6.12.9 (H) - Subdivision roads and related infrastructure CODE states (H) Dead end roads shall not exceed 1,500 feet and shall have a cul-de-sac at the terminal end. Refer to details in Section 7.3.1. Dead end roads intended to provide future access to adjacent unplatted areas may be permitted without a cul-de-sac provided that no lots front thereon, the length does not exceed 1,500 feet, and appropriate temporary end-of-road markers are provided. APPLICANT Request a waiver for dead end road without cul-de-sac. A hammerhead with dead end segments less than 150' in length have been provided as an alternative turn around. LDC 6.12.9 - Subdivision roads and related infrastructure CODE states A. In residential subdivisions, the road system shall be designed to serve the needs of the neighborhood and to discourage use by truck traffic and through traffic and still provide access to adjacent neighborhoods for emergency services. The use of neighborhood traffic calming devices such as traffic circles, cul-de-sac, etc. are encouraged in residential areas. B. Major local roads shall be identified on plans. C. All roads and related infrastructure within the proposed subdivision shall be designed, constructed, and paved to County specifications provided herein. D. The developer shall be required to design, construct, and pave to County specifications, one road from the subdivision to the nearest paved, public roadway with legal access, if such a road does not already exist. E. Roads and stormwater facilities within a subdivision shall be dedicated as either public or private. F. Public dedications shall be pre-approved by the Development Review Committee. If a MSBU is established as the maintenance and operation entity, roads and stormwater facilities can be platted as public. G. Cul-de-sac diameters to the right-of-way line shall not be less than 120 feet with a pavement radius of 40 feet for residential subdivisions and shall not be less than 120 feet to the right-of-way line with a pavement radius of 45 feet for commercial or industrial subdivisions. Refer to details in Section 7.3.1. A grassed island no greater than 50 feet in diameter may be constructed in the center of a cul-de-sac. H. Dead end roads shall not exceed 1,500 feet and shall have a cul-de-sac at the terminal end. Refer to details in Section 7.3.1. Dead end roads intended to provide future access to adjacent unplatted areas may be permitted without a cul-de-sac provided that no lots front thereon, the length does not exceed 1,500 feet, and appropriate temporary end-of-road markers are provided. I. The total perimeter of a block shall not exceed 4,500 feet. Larger block perimeters will be permitted for blocks surrounding or adjacent to natural or artificial features such as lakes, rivers, and golf courses where limiting block lengths are not feasible and impractical. J. Corner radii at the intersection of the two rights-of-way shall be not less than 25 feet. Minimum pavement radii shall be 40 feet for residential subdivisions and 50 feet for commercial or industrial subdivisions. K. Centerline radii shall be designed to accommodate the minimum design speed of 30 mph for subdivision local and minor local roads, 40 mph for major local and collector roads, and 45 mph for arterial roads in accordance with FDOT and AASHTO Standards. L. Evacuation routes for developments shall be indicated on the improvement plans. APPLICANT Request a waiver for the roadway centerlines not meeting centerline radii for 30 mph design speed. Proposed curves warranting lower design speeds will have proper signage. LDC 6.13.7 - Geotechnical criteria CODE states A. Methodology. The pattern and type of test borings shall be determined by the project engineer, geotechnical engineer, or geologist based on the project size, type, and complexity. (1) Infiltration/permeability rate tests shall follow methods acceptable to the governing State agency and shall be performed at the depth and location which will provide representative test results for use in the design of the retention/detention area. Soil identifications shall refer to the AASHTO Soil Classification System conforming to AASHTO Designation M 145-91. (2) Where visual reconnaissance, available published data, and/or initial borings suggest high karst sensitivity or lithologic variability, additional borings may be required if deemed necessary by the County Engineer or his designee. B. Minimum requirements. (1) Depth. Soil test borings shall be performed to a minimum depth of 10 feet below the proposed finished grade of the bottom of all retention/detention areas or the permanent pool elevation and once the data has been obtained the hole shall be backfilled and compacted. (2) Number of tests. At least two tests shall be performed within the boundary of each proposed retention/detention area. For each half acre of pond bottom area and for each lineal retention/detention area of 250 feet, an additional test shall be conducted. The County Engineer or his designee, may require additional tests if the initial tests indicate the need for them. (3) Infiltration/permeability tests. For retention/detention areas utilizing percolation or infiltration in the design model, there shall be a minimum of two infiltration rate tests for each retention/detention area. Data used for soil permeability testing or infiltration analyses for the retention/detention areas shall be signed and sealed by a professional engineer or professional geologist for both data and procedural accuracy. (4) Aquifer parameters. The estimated seasonal high ground water elevation and confining layer shall be clearly identified. C. Design considerations. (1) The estimated seasonal high water elevation and the confining layer shall be set no lower than the bottom of the boring for the purposes of stormwater system modeling. (2) The pond bottom elevation of a stormwater facility shall be designed a minimum of 1 foot above the estimated seasonal high water elevation. When the pond bottom is within 1 foot of the estimated seasonal high water elevation, a 50 percent reduction factor shall be used for percolation or ground water mounding analysis shall be included. APPLICANT Waiver requested to providing an additional soil boring in DRA 5. The provided soil borings are all consistent.