Green Infrastructure for Sustainable Shoreline

Firm:Infrastructure Engineering Inc.

Other Consultants:Bleck Engineering Company, Inc., Campanella & Sons, Inc.

Owner:City of Waukegan

Description:The City of Waukegan was the recipient of a grant from the United States Environmental Protection Agency (EPA) to reduce pollutant load to Lake Michigan through the annual capture volume of 1.1M gallons of stormwater runoff from nearly thirteen acres of impervious surfaces. Green infrastructure was to be used to filter suspended solids, bacteria, and chemicals from stormwater runoff prior to the eventual discharge to Lake Michigan.

Stormwater runoff from Sea Horse Drive and the parking lots adjacent to the municipal beach show the characteristics of typical urban runoff. Surface flow often contains suspended solids, oil, and grease from parking lots full of vehicles, e-coli from shorebird droppings and chlorides from winter deicing applications. Runoff from these impervious areas contribute to poor water quality at the shore of Lake Michigan, in a recreational area adjacent to high quality wetlands and sensitive habitats.

The solution to reducing stormwater runoff from large expanses of impervious areas was to construct a vegetated channel to collect and treat the high volume of runoff during regular peak rain events. The vegetated channel (bioswale) at the Waukegan Municipal Beach is approximately 3000 lineal feet consisting of an over excavated area filled with open graded aggregate, filter fabric, an engineering growing medium, a soil mixture of topsoil and compost, and mulch to hold the swale assembly in place. Native plants appropriate for the growing environment are planted densely along the length of the bioswale.

The City of Waukegan used the Spreadsheet Tool for Estimating Pollutant Loads (STEP-L), a model recommended and technically supported by the EPA to calculate the reductions in nonpoint source pollution that will be achieved as a result of the Best Management Practices (BMPs) put in place. STEP-L employs simple algorithms to calculate nutrient and sediment loads from different land uses and the load reductions that would result from the implementation of various BMPs.

Today the bioswale highlights the access to the City of Waukegan’s Municipal Beach with vegetation appropriate for butterflies and other pollinators helping to improve the local ecosystem.

City of Waukegan

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