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CHAPTER 1 Introduction The fundamental purpose and goal of this pilot test was to evaluate and propose enhancements to the Transportation for CommunitiesâAdvancing Projects through Partnerships (TCAPP) collaborative planning tool. The focus was on assessing the toolâs value in providing guidance to help project partners work collaboratively toward environmental permitting decisions for South Carolina Department of Transportation (SCDOT) projects. The project team, led by the SCDOT, used the tool from July 2013 through December 2013 to evaluate a proposed bridge replacement over Hoopstick Creek on Johns Island, South Carolina. The project team recognizes that the selected pilot project may be perceived as âroutineâ for most transportation agencies. Routine projects are those transportation improvements that undergo National Environmental Policy Act (NEPA) review as a categorical exclusion and/or Clean Water Act permitting through the SCDOTâs general permit. Typical routine projects may include intersection improvements, bridge replacements, and roadway maintenance. These types of projects account for the greatest quantity of NEPA reviews and permit applications within the SCDOT. The Hoopstick Creek Bridge Replacement is located in coastal South Carolina; therefore, the project involves a majority of, if not all, state and federal resource and regulatory agencies. A pilot test of TCAPP on this project is useful because routine projects typically require a disproportionate amount of time in the environmental process compared with large or complex projects. While complex projects receive greater attention and collaboration from agency partners, the SCDOT has recognized the need for improved coordination on projects like Hoopstick Creek Bridge Replacement. Evaluating TCAPP was useful for the SCDOT because the toolâs Decision Guide provided structure to the environmental process for routine projects. Project Context: Hoopstick Creek The pilot project used to evaluate TCAPP is a proposed bridge replacement on Bohicket Road (State Road 10-20) over Hoopstick Creek, a tidally influenced creek, on Johns Island, South Carolina, in Charleston County (Figure 1.1). It was selected to include the agencies and issues for which the project team hopes to improve coordination. The timing of the project also corresponded with the timing of the second Strategic Highway Research Program (SHRP 2) project funds, meaning that coordination must occur to let the project in fall 2014. The existing bridge measures 60 ft by 33 ft and has been evaluated as structurally deficient and functionally obsolete in accordance with federal bridge inspection standards. The bridge has an overall sufficiency rating of 41, making it eligible for repair, rehabilitation, or replacement through the Highway Bridge Replacement and Rehabilitation Program. The substructure of the existing bridge is in poor condition, exhibiting evidence of advanced corrosion and deterioration due to scour activity. Bohicket Road is classified as a minor arterial roadway that serves as the hurricane evacuation route on Johns Island. The existing bridge and its approach roads also do not meet 5
current design and safety guidelines for a minor arterial roadway carrying over 12,000 vehicles per day. The typical section for the existing bridge consists of two 12-ft travel lanes with 2-ft shoulders. Current design guidelines for a bridge on a minor arterial roadway require 12-ft travel lanes and 10-ft shoulders. The average daily traffic (ADT) on Bohicket Road over Hoopstick Creek in 2012 was 12,400 vehicles per day. The 2035 Charleston Area Transportation Study (CHATS) long-range transportation plan identifies this portion of Bohicket Road as a congested corridor. Figure 1.1. Location of Hoopstick Creek Bridge Replacement project. (Source: Google Maps.) Proposed Bridge Replacement over Hoopstick Creek 6
The curvature and geometric design of the existing roadway also contribute to poor line- of-sight conditions along Bohicket Road. The line of sight along a roadway plays an important role in the amount of time drivers have to stop due to an obstruction or turning vehicle. The Plowground Road intersection (Figure 1.2) is located less than 150 ft south of the Hoopstick Creek Bridge. The existing bridge over Hoopstick Creek does not provide any storage for vehicles coming off the bridge and turning onto Plowground Road, which leads to an unsafe roadway condition. Between January 2010 and April 2013, a total of seven crashes occurred at the intersection of Bohicket Road and Plowground Road. Figure 1.2. Bohicket Road and Plowground Road intersection, bridge to north. (Source: Google Maps Street View.) Past Permitting and NEPA Evaluations The project was originally proposed in combination with a nearby bridge replacement over Bohicket Creek, also on State Road 10-20 (Figure 1.3). The projects were previously approved under a categorical exclusion on January 14, 2004. A U.S. Army Corps of Engineers (USACE) nationwide permit was issued for the projects in March 2005. The bridge over Bohicket Creek was replaced in 2009; however, limited funding prevented the SCDOT from constructing the bridge over Hoopstick Creek. 7
Figure 1.3. Aerial photograph of Hoopstick Creek Bridge Replacement project. (Source: Google Earth.) Proposed Project The proposed project includes replacement of the existing bridge with a prestressed concrete structure measuring 90 ft by 49 ft. The typical section of the new bridge would consist of two 12- ft travel lanes, one 15-ft left turn lane, and 5-ft shoulders. A turn lane is also being considered on the new bridge to accommodate turning movements onto Plowground Road (2011 ADT = 1,180) and to improve the overall safety of the existing roadway. It is anticipated that the addition of the 15-ft turn lane would improve the safety of the bridge and the Bohicket Road/Plowground Road intersection. The Hoopstick Creek Bridge Replacement meets the requirements of a USACE regional general permit for highway projects in which impacts to tidal waters are expected to be less than 0.5 acres. The project is also being reevaluated in compliance with the NEPA as a categorical exclusion. Environmental Considerations Wetlands and Essential Fish Habitat Tidally influenced areas, such as Hoopstick Creek and its adjacent salt marsh, are considered âcritical areaâ by the state of South Carolina. These resources are managed by the South Carolina Department of Health and Environmental Control (SCDHEC) Office of Ocean and Coastal Resource Management (OCRM). Tidal areas are also regulated by the USACE as waters protected by Section 10 of the Rivers and Harbors Act. Hoopstick Creek is a small tidal creek that drains to a larger creek and marsh system, known as Bohicket Creek (Figure 1.4). Bohicket Creek is classified as outstanding Proposed Bridge Replacement over Hoopstick Creek S-20 Bridge Replaced over Bohicket Creek in 2009 8
resource waters according to the SCDHEC water classification system (R. 61-69 Classified Waters, June 22, 2012). Hoopstick Creek and its adjacent salt marsh are wider south of the bridge, narrowing and transitioning to a freshwater system north of the bridge. The salt marsh, or estuarine emergent wetlands, is important for many invertebrates and provides nursery grounds for other species. The tidal marshes surrounding Hoopstick Creek contain saltmarsh cordgrass (Spartina alterniflora), needlegrass (Juncus roemerianus), and big cordgrass (Spartina cynosuroides). There are no shellfish beds within 1,000 ft of the project. Three habitat types that are designated as essential fish habitat by the South Atlantic Fishery Management Council are present within the project area: a tidal creek (Hoopstick Creek), estuarine emergent wetlands, and inter/subtidal unvegetated flats. Figure 1.4. Salt marsh south of existing Hoopstick Creek Bridge. (Source: Blair Goodman Wade.) Live Oak Canopy The project corridor is located within a 10.34-mile segment of Bohicket Road that has been designated as a state scenic highway. Bohicket Road was one of the first designated scenic highways in the state of South Carolina. As is typical of the South Carolina Lowcountry, large live oak (Quercus virginiana) trees border State Road 10-20 as it approaches Hoopstick Creek (Figure 1.5). Any tree measuring 24 inches or greater diameter at breast height, except pines, is considered a grand tree by Charleston County, where the project is located. Article 9.4, Tree Protection and Preservation, of the Charleston County Zoning and Land Development Ordinance requires a variance request to the County Board of Zoning Appeals to remove any trees as part of the bridge replacement. Because of this ordinance and the treesâ iconic status in the Lowcountry, the SCDOT evaluates impacts to the live oaks when considering bridge and approach alignments. 9
