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Metropolitan Water Reclamation District of Greater Chicago

The flat landscape of the Chicago region is naturally flood prone. Much of this area that is now home to over 5 million people was originally marshland with slow moving rivers and streams that would flood often. 

Since it was founded in 1889, the MWRD has worked to reduce flooding and provide drainage for the Chicago region. We have led the world in innovative flood control technology and have made major investments in vast infrastructure. Today we’re meeting the challenge of increasingly intense rainfall with a combination of traditional flood control measures and green infrastructure. 

The Chicago Area Waterway System

The MWRD was founded to build a canal to reverse the flow of the Chicago River to provide drainage for the region, protect Lake Michigan from pollution and to establish a navigation link between the Mississippi River watershed and the Great Lakes. Today, we operate the 76.1 mile long Chicago Area Waterway System which consists of three canals and altered portions of natural rivers. This essential infrastructure provides drainage for the region and navigable waterways. 

Tunnel and Reservoir Plan (TARP)

The MWRD’s Tunnel and Reservoir Plan (TARP) reduces flooding by capturing water that would have otherwise overflowed from the sewer system into waterways. The water is held in TARP tunnels and reservoirs until after the rain passes and is pumped to water reclamation plants to be cleaned. By keeping this extra water out of waterways during rainy weather, TARP helps reduce flooding. 

Channel improvements

MWRD Channel improvement projects help water drain more effectively through area streams, reducing the likelihood of flooding. Removing obstructions, widening, and deepening stream channels allows more water to flow through them. Channel improvements also often include stabilizing the banks of streams to prevent erosion. 

A small waterway with numerous rocks on one side and seeded ground on the other, part of a streambank stabilization project to reduce erosion
Streambank stabilization in Midlothian.


Flood control reservoirs

Flood control reservoirs are designed to hold water from rivers and streams that could contribute to flooding. The water is held in reservoirs until after the rain passes and is pumped back into the stream. 

Sewer improvements

The MWRD partners with municipalities to build new storm sewers or improve existing ones. Damaged or undersized sewers can contribute to flooding. 

Watershed Management Ordinance

Our Watershed Management Ordinance helps reduce additional flooding caused by development. Under the WMO, new development is required to incorporate controls to reduce runoff that could contribute to flooding. 

Green infrastructure

Green infrastructure helps reduce flooding and runoff pollution by soaking up and holding rainwater where it falls. We partner with municipalities to build green infrastructure throughout the Chicago region.

We also use several types of green infrastructure at our own facilities and provide resources for homeowners to go green, too!

The MWRD leases our property throughout the region, and we recommend voluntary implementation of green infrastructure installations in commercial or industrial leases. We also require green infrastructure installation for public leases. 

Stream maintenance

Our Small Stream Maintenance Program removes obstructions and debris that could slow natural drainage in small streams and rivers throughout Cook County. Blockages in rivers and streams can cause standing or slow water upstream and contribute to flooding. 

Native Landscaping

Native plants and trees help soak up more rainwater than other types of landscaping. They are natural green infrastructure that helps to reduce flooding and runoff pollution. We give away free native tree saplings, wildflower seeds, and milkweed seeds to residents. 

Yellow native flowers in the foreground with white digesters in the distance
A goat in the shade under a tree

Native prairie landscaping at our water reclamation plants

We have over 50 acres of native landscaping on the grounds of our facilities. We use goats and sheep as a sustainable method of maintaining these natural landscapes.