Board of Adjustment Agenda and Packet 2016 11 16

Home Browse Search

BACKGROUND: The City approved the Coal Creek Business Park PUD for the business park campus in 1997, followed by approval of a site development PUD for the subject property in 1998. Construction of the original building took place in 1999. Staff has not been able to locate any previous Floodplain Development Permits for the property. The Coal Creek Business Park campus includes five developed lots with a mix of commercial and office uses totaling over 300,000 square feet of developed area. The US 36 right of way, Coal Creek and the Coal Creek Golf Course border the property to the south and east. The other Coal Creek Business Park lots border the property to the north and west. The current regulatory map covering the property is the December 18, 2012 Federal Emergency Management Agency (FEMA) Flood Insurance Rate Map (FIRM). Local Boulder County jurisdictions, including Louisville, recently completed a 2014 Flood Hazard Area Delineation Study (FHAD) for Coal Creek. The FHAD covers this property and staff anticipates that the FHAD will result in updated FEMA maps in the near future. For this reason, staff requested that the applicant analyze the floodplain based on both the currently adopted FIRM and the FHAD. ANALYSIS: Chapter 17.56 of the Louisville Municipal Code (LMC) provides procedures, regulations and requirements for Floodplain Development Permits. The Board of Adjustment is to review Floodplain Development Permit requests at a public hearing and may grant or deny a request based on compliance of the application with the applicable regulations and review criteria in the Code. The following contains staff's analysis and recommended findings on the applicable regulations and criteria for this request. LMC Sec. 17.56.160 — Flood Regulatory District Regulations According to LMC Sec. 17.56160, the cumulative effects of any proposed development may not cause a rise in the base flood elevations by more than one-half foot at any point. A registered professional engineer must make certification that such increase in flood levels will not occur. The applicant's engineer has provided a floodplain study with hydraulic analysis of the proposed development showing there will be no rise in the base flood elevations using both the FIRM and FHAD data (see pp. 6-9 of attached Floodplain Study, Revision Date Oct. 26, 2016). Staff finds that the proposal is in compliance this requirement. In addition, LMC Sec. 17.56160 require anchoring of structures in the Flood Regulatory District be and either the finished floor of the building is a least one -foot above the base flood elevation or the structure must incorporates floodproofing for any portion of the structure below the base flood elevation in compliance with the LMC. The proposed finished floor elevation of 5456.10 is slightly below the base flood elevation of 5456.83. Therefore, the structure must include floodproofing. The Floodplain Study states that the applicant will provide floodproofing measures for all potions of the building below the base flood elevation (see p. 10 of attached Floodplain Study, Revision Date Oct. 26, 2016). The Study states that this may include use of waterproof coatings, impermeable membranes or supplemental use of masonry to create waterproof walls, use of flood gates for doors, windows or other openings and backflow valves for sewer lines and drains. The Study further states that the floodproofing must be designed to resist hydrostatic and hydrodynamic forces applicable to the floodplain adjacent to the structure. If this project received Floodplain Development Permit and PUD approval, the application will be required to provide detailed construction drawings demonstrating the floodproofing methods at the time of building permit review. 3