Lake County has been experiencing more frequent and stronger rainfall events. Recently, the Illinois State Water Survey released updated statistical rainfall data for Bulletin 70--Frequency Distributions of Heavy Precipitation in Illinois. This new data impacts not only the residents and business owners of Lake County, but also public and private development projects. SMC will be making revisions to the Watershed Development Ordinance (WDO), a countywide ordinance that sets forth minimum requirements for the stormwater management aspects of development within Lake County
SMC presented the increased rainfall data along with a timeline of the regulatory process, provide resources and tools for best practices, and discuss stormwater-related issues and concerns from the audience. Members of the public, stakeholders, and individuals with an interest in hearing more about how rainfall affects Lake County were encouraged to attend.
The Upper Des Plaines River inundation map prepared by the Illinois Office of Water Resources breaks the River up into three sections corresponding to the USGS river gages: Russell, Gurnee/Route 120 and Lincolnshire. The inundation map has a slider for river stage. River stage is the depth of water above the gage datum which is somewhere below the typical lowest river level anticipated. This table compares the “Year Flood” to the stage at each of the gage locations to give an idea of how significant a given stage is. For example, a “100-year” flood at the Russell gage is at a Stage of 14.