Project Info:

Location: Sullivan County, New York

Role: Prime

Owner: New York State Department of Transportation

Client: New York State Department of Transportation

Construction Cost: $94,000,000


  • Interstate Design
  • Highway/Roadway Design
  • Sustainable Design/Construction Features
  • Structural Design
  • Diamond Interchange Design
  • Hydraulic Analysis/Design
  • Hydrologic Analysis/Design
  • Stream Stability Assessment/Mitigation
  • Trail Planning/Design
  • Culvert Design
  • Parking Facility Design
  • Retaining Wall Design
  • Culinary Water System Design
  • Digital Terrain Modeling
  • Alternatives Development and Analysis
  • Environmental Impact Statement
  • Public Outreach/Involvement
  • Stakeholder Committee Group Coordination
  • Final Plans, Specifications, and Estimates (PS&E)
  • Constructability Review


2008 New York State Department of Transportation GreenLITES Program Gold Certification

2013 American Council of Engineering Companies (ACEC) New York Diamond Award, Transportation


In 1998, the New York State Department of Transportation (NYSDOT) began the process of converting Route 17 into a fully access-controlled facility, to be designated Interstate 86. Extending over 390 miles from Lake Erie to the lower Hudson Valley, the predominantly limited-access facility was split into numerous projects for design and construction. Lochner was selected to complete preliminary and final design phases for the conversion of a three-mile section of this stretch of roadway. The project ran through the hamlet of Parksville and along a highly valued watershed, the Beaver Kill. Often referred to as “Beamoc,” the watershed is regarded as the birthplace of American fly fishing, making it one of the premier recreational fishing destinations in the United States and a significant contributor to the local and regional economy.

With this cultural significance and environmental sensitivity, Lochner collaborated extensively with various stakeholders to develop and evaluate feasible alternatives. The Beamoc Study Group, a joint working group comprised of the New York State Department of Environmental Conservation (NYSDEC) and NYSDOT personnel dedicated to studying effects on and conservation efforts to the Beamoc water bodies, along with a steering committee of local elected officials, business owners, and residents, worked together to identify key issues, address concerns, and build consensus.

During the preliminary design phase, Lochner developed several alternatives—both on and off the existing alignment—as well as a draft environmental impact statement detailing the potential environmental, historic, cultural, socioeconomic, and other impacts of construction in this highly sensitive area. The alternatives included interchanges, grade separation structures, new local roads, retaining walls, stream restoration, wetland mitigation, and other environmental and landscaping enhancements. One alternative generally followed the existing alignment and required the removal of 10 residential homes and nine commercial establishments. The other three alternatives, on alignment south of Parksville, left the town intact with few or no acquisitions, but traversed steep valley walls and a series of ravines, streams, and cold water seeps that provide the base flow and thermal stability vital for a healthy trout habitat. Ultimately, a southerly bypass alternative was selected and progressed through record of decision and design approval.

Final design of the new four-lane interstate included a diamond interchange; seven and a half miles of local road improvements, including the removal of existing eastbound lanes to convert the four-lane Route 17 into a two-lane local road; 3,000 feet of retaining walls; 13 new bridges, some single and multi-span; four bridge rehabilitations; and four bridge removals. Most of the bridges were designed as steel multi-girder bridges, however, one was designed as a prestressed concrete New England Bulb Tee (NEBT) multi-girder bridge to better address clearance requirements. Lochner’s design also upgraded a walking trail along an abandoned railroad bed and created a new parking area at the western trail head to improve access to fishing areas.

During the design, Lochner used three-dimensional models of bridge foundations to ensure that the substructures– and the excavation necessary to construct them– did not impact protected areas. To preserve and protect the watershed, the design included stream restoration, wetland mitigation, and many unique aspects such as:

  • Do Not Disturb zones in the most sensitive areas, in which heavy equipment was prohibited, and the contractor was limited to hand clearing.
  • Eastbound and westbound viaducts, longer than hydraulically necessary to preserve cold water seeps and wildlife movement. Each was over 800 feet in length. Two three-sided arch structures were also used to span a smaller ravine. Closed drainage was placed on the superstructures to prevent untreated runoff from entering the water system.
  • Mainline structures over Little Coddington Brook, longer than hydraulically necessary to maintain existing habitat, accommodate wildlife movement, and minimize impacts to the stream.
  • Superstructures for which steel girder splices do not require the placement of temporary bents within the protected areas.
  • Stormwater treatment ponds with 12-hour maximum detention times and the preservation of existing shade trees to minimize the potential of thermal impacts.
  • A water quality monitoring program in which peak flow and water temperature data were collected and documented before, during, and at the end of construction.

Given the extreme complexity of the terrain and ecosystem, Lochner assisted NYSDOT in administering a constructability review period, in which contractors were provided advanced contract drawings, three-dimensional models, cross sections, geographic information, and the environmental restrictions. The consensus among the contractors was that the project, as designed, was constructable and ready to be bid.