Location
Ringwood Rd, Lake Forest, IL
Client
Services Provided
Project Overview
The City of Lake Forest identified a critical infrastructure issue when a headwall at the upstream end of the culvert beneath the Ringwood Road land bridge collapsed, obstructing water flow through Walden Ravine. In response, Bleck Engineering was retained to evaluate the structural stability of the ravine and conduct a comprehensive survey of both its upstream and downstream segments. The culvert, a brick structure over a century old, was in need of substantial rehabilitation. The project was approached through a multi-phase design process focused on restoring aging infrastructure, improving water quality within the ravine, and enhancing roadway safety.
On the upstream side of the ravine, the design included the construction of a new concrete headwall and the restoration of approximately 130 linear feet of stream channel. This restoration incorporated hydraulic features such as rock riffles and stone step pools to moderate water flow, along with channel armoring using glacial and fluvial stone to control erosion. Toe protection was also provided, incorporating crevices designed to support amphibian habitat. Additionally, the ravine bottom was stabilized and revitalized through the use of native plantings to support long-term ecological health. To preserve the existing culvert, a spray-in-place pipe lining method was used to reinforce its structural integrity while minimizing disturbance to the surrounding environment.
On the downstream side, a new storm sewer system was installed to effectively manage roadway drainage. This system included three separate drainage structures, each protected with glacial and fluvial stone to dissipate energy and prevent scour along the ravine slopes. Toe protection was further reinforced with the installation of gabion baskets and additional stone armoring, ensuring long-term slope stability.
As part of the roadway improvements, approximately 300 feet of Ringwood Road was milled and resurfaced. A B6.12 combination curb and gutter system was installed along the land bridge to control stormwater runoff and reduce erosion along the ravine slopes. To improve vehicular safety, timber guardrails were placed along both sides of the roadway, addressing the steep 35-foot drop from the bridge to the ravine bed below.
Following completion of the design, Bleck Engineering provided permitting assistance to the City of Lake Forest, coordinating with Lake County Stormwater Management Commission, the Illinois Environmental Protection Agency, and the U.S. Army Corps of Engineers to secure all necessary regulatory approvals for the project.
