Areas designated as critical drainage areas in Save The Dunes' October 2015 document Little Calumet River, East Branch Watershed Management Plan. The areas are designated in text on page 155 of the document. The areas were mapped by delineating watersheds upstream of the points described using the United States Geological Survey's Stream Stats website and modifying the resulting polygons with upstream boundary points where applicable.

The following text is taken from page 153 of the aforementioned management plan.

Critical areas are locations with the most degraded water quality. These areas have been given highest priority for the implementation of restoration funds and activities. The designated critical areas are likely the largest contributors of pollutant loads in the watershed.

Conversely, protection areas have the highest water quality in the watershed. These areas are crucial for the long-term environmental health of the watershed and require protective measures to maintain or enhance existing water quality. The protection of these areas will prevent future degradation to promote higher water quality throughout the watershed.