Lyon’s Creek Underpass Design

Abstract

This project involves a site on Lyon’s Creek Road along Little Prickly Pear Creek in Lewis and Clark County, MT, in which the rural road runs underneath a low-clearance railroad trestle bridge. The site is located just south of Wolf Creek, MT, at the junction of Little Prickly Pear Creek and Lyon’s Creek. This area often experiences moderate to high runoff events causing the creek to overflow its banks and flood the road. Along with flooding events, the lowclearance under the railroad bridge forces large trucks to either detour many miles around the site, or excavate and replace the road underneath the bridge after navigating the crossing. This restricts access to many necessary utilities for a sizable number of residents that live west of the crossing. The Lewis and Clark County Public Works Department and County Engineer Dan Karlin desire a sustainable solution that will allow high clearance vehicles to navigate the trestle during the flooding season, and enhance the safety of the existing site. Our task is to work with Mr. Karlin to design a solution that will enhance the safety and sustainability of the site, while simultaneously creating enough clearance underneath the railroad bridge to safely maneuver a large utility truck through. To complete the project, we must take the necessary steps essential to Engineering Design to ensure that our solution will meet all criteria and constraints, enhance public safety and access, and maintain healthy environmental conditions.