I-15 South, MP 0 to MP 16 Environmental Assessment Public Hearing August 7, 2012 5:00 PM to 7:00 PM 1
PROJECT OVERVIEW The Federal Highway Administration (FHWA) and the Utah Department of Transportation (UDOT) have completed an Environmental Assessment (EA) to analyze the need for transportation improvements to I-15 between mileposts 0 and 16 in Washington County, UtahThe. EA identifies current and future transportation needs within the project area and evaluates alternatives and their associated impacts to the natural and built environment. 2
Project Purpose The purpose of the project is to address the projected 2040 travel demand on the I-15 corridor between MP 0 and MP 16. PURPOSE AND NEED Project Need The project is needed because the I-15 corridor between MP 0 and MP 16 lacks the capacity to accommodate the 2040 future travel demand. The projected travel demand will increase congestion on I-15 between MP 0 and MP 16. The increasing congestion will be a result of: Population growth Traffic volume growth High volumes of freight traffic 3
Level-of-Service Level-of-Service (LOS) characterizes the traffic operations of a roadway in terms of: speed average travel delay travel times freedom to maneuver driver comfort/convenience LOS ranges from A to F (see table). For planning purposes, facilities with current or projected 2040 LOS D or better are acceptable for urbanized areas. Between the Southern Parkway and SR-9, I-15 will operate at an unacceptable LOS in 2040. EXISTING AND PROJECTED TRAFFIC Existing Traffic Projected 2040 No-action Traffic 4
Dixie Metropolitan Planning Organization CONSISTENCY WITH LOCAL PLANS I-15 is listed for widening from MP 0 to MP 16 in the Dixie Metropolitan Planning Organization s 2011 2040 Regional Transportation Plan City of St. George The St. George Master Traffic and Transportation Study (2008) recognizes the need for capacity improvements to I-15 in the study area 5
The Preferred Alternative would include: PREFERRED ALTERNATIVE Constructing an additional general purpose lane on I-15 in both the northbound and southbound directions between Southern Parkway and SR-9 Constructing auxiliary lanes between the Port-of-Entry and Southern Parkway, Brigham Road and Dixie i Drive, and Washington Parkway and SR-9 Improving and/or re-configuring interchanges at: Brigham Road St. George Boulevard Green Springs Drive SR-9 6
Environmental Issue Pedestrian and Bicyclist Issues Noise Cultural l Resources SUMMARY OF IMPACTS AND MITIGATION Preferred Alternative Would construct new pedestrian facilities that would cross I- 15 at Brigham Road and St. George Boulevard Noise levels would increase over existing noise levels (noise levels l would range from 58 dba to 81 dba, with an average noise level of about 66 dba) Would have an overall adverse effect on historic properties Wtl Wetlands No impacts to wetlands, minor impacts to four drainages Water Quality Floodplains Would increase impervious surface area by 41% over existing I-15 Detention basins and Best Management Practices would be used to treat t increases in stormwater t runoff, resulting in a minimal effect to water quality Impacts to floodplains would not cause a 1 foot increase in the 100-year flood elevation Mitigation No mitigation required 8 noise walls meet criteria outlined in UDOT s Noise Policy and are recommended, pending balloting efforts (see map) A Programmatic Agreement (PA) will be developed to resolve potential adverse effects The PA will require development of a written data recovery plan and research design Section 404 Permit will be obtained from the U.S. Army Corps of Engineers Detention ponds will be provided for water quality treatment where necessary to detain runoff to reduce peak flow rate Will comply with applicable local, state, and federal regulations 7
Environmental Issue Threatened & Endangered Species Wildlife SUMMARY OF IMPACTS AND MITIGATION Preferred Alternative Likely to adversely affect the desert tortoise and desert tortoise Critical Habitat Likely to adversely affect the dwarf bear-poppy Likely to adversely affect the holmgren milk-vetch and holmgren milk- vetch Critical Habitat. Likely to adversely affect the Virgin River chub and Virgin River chub Critical Habitat Likely to adversely affect the woundfin and woundfin Critical Habitat Not likely l to adversely affect the southwestern t willow flycatcher and would not affect southwestern willow flycatcher Critical Habitat Not likely to adversely affect the yellow-billed cuckoo and would not affect yellow-billed cuckoo Critical Habitat Would negatively affect the Virgin spinedace and the flannelmouth sucker Mitigation Requirements outlined in the Biological Opinion from the U.S. Fish and Wildlife Service will be implemented to reduce the effect to Threatened ed & Endangered ed Species Same requirements outlined in the Biological Opinion from the U.S. Fish and Wildlife Service will be implemented 8
NOISE WALLS The UDOT Noise Abatement Policy states that noise walls will only be considered for properties that are impacted by noise. Typical Noise Levels in A-weighted decibels (dba) How Does UDOT Define a Noise Impact? 66 dba or more for residences, schools, churches 71 dba or more for businesses OR 10 dba or more above the existing noise level 9
NOISE WALLS How does UDOT determine if a noise wall will be constructed? The UDOT Noise Abatement Policy states that the following criteria must be met: Noise walls need to reduce noise levels by at least 8 dba to properties adjacent to the noise wall The cost of noise walls must be reasonable Property owners and residences need to be in favor of noise walls (balloting would be conducted during the design phase, should a build alternative be selected) Where is the I-15 South Environmental Assessment recommending noise walls? See map for potential noise wall locations (pending balloting efforts) 10
WHAT COULD THE NOISE WALLS LOOK LIKE? The UDOT Standard Drawings identify five panel surface texture options for noise walls: Ashlar Stone Exposed Aggregate Fractured Fin River Rock Stacked Stone 11
ENVIRONMENTAL ASSESSMENT PROCESS & SCHEDULE 12
Old Slides 13
BRIGHAM ROAD INTERCHANGE OPTIONS The Single Point Interchange (SPI) Option was selected for the following reasons: Provides for better interchange driver expectancy Would eliminate the roundabouts and alleviate public concerns Would better accommodate heavy truck movements 14
ST. GEORGE BOULEVARD INTERCHANGE OPTIONS The Diverging Diamond Interchange (DDI) Option was selected for the following reasons: Would use the existing bridge structure Provides for better traffic operations and performance than the Tight Diamond Option, and is comparable to the Single Point Option 15
SR-9 INTERCHANGE OPTIONS The Trumpet Option was selected for the following reasons: Would use existing infrastructure by closely matching the existing design layout/footprint Provides for better traffic operations and performance Provides for better safety since all conflicts are removed 16
KEY ENVIRONMENTAL ISSUES Archaeology Floodplains l Prehistoric (Lithic Scatters, Rock Shelter, Camp Sites, Habitation, Rock Art) Historic (Settlement, Farming and Ranching, Mining, Transportation) Noise Noise walls were evaluated for a number of residential and commercial areas Virgin and Santa Clara Rivers Stream/Wash crossings Threatened & Endangered Species Bird (Southwest Willow Flycatcher, Western Yellowbilled Cuckoo) Fish (Virgin River Chub, Woundfin Minnow) Plant (Dwarf Bear Poppy, Holmgren Milk-vetch) Reptile (Desert Tortoise) 17