Agency Identification of a Preferred Alternative

The environmental review of the proposed North Unit visitor center did not identify an agency preferred alternative because the NPS sought additional input from the Watford City community members who identified the location of the now abandoned visitor center. In the EA, the NPS explored three locations using a pier-based foundation design that would be more stable than the original location and foundation design. In identifying the preferred alternative the NPS considered public comments, environmental variables, associated costs, and reasonable construction schedules.

Alternative Site #1 was selected as the Preferred Alternative for the new visitor center largely because the current access road, parking lot, and utilities (water, sewer and electric) can be utilized with minimal cost and environmental impact. The other alternative sites would involve replacement or substantial relocation of these facilities with an associated increase in environmental impact. A frequently expressed concern expressed with Alternative Site #1 was the expansive soils would still pose problems similar to the abandoned visitor center issues. Engineers have determined that construction of a one-story structure (the abandoned visitor center had a basement) atop a drilled pier foundation system would stabilize the building in spite of soil movement under the building and therefore resolve previous expansive soil problems that caused the adjacent building failure near Alternative Site #1. Furthermore, the NPS would minimize capital investment costs by building the new facility at Alternative Site #1.

In comparison, construction on the other alternative sites would be more costly and difficult to fund resulting in delayed facility replacement. Alternative Site #2 could utilize some of the existing parking lot but there would be Americans with Disabilities Act compliance issues resulting from the existing grade. The steep slope would exacerbate the movement of expansive soils underlying sidewalks and ramps. Alternative Site #3 could use the existing parking lot as "overflow" parking but there would be a safety concern with visitors crossing traffic to get to the new building. This alternative would also require minor utility re-routing (water, sewer and electric) and construction of a new access road and parking area. Alternative Site #4 would require installation of new utilities (water, sewer, and electric), a new access road, and construction of a new parking lot.

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