The Clean Water Act requires active, local stormwater management. In 2004 the Illinois General Assembly recognized the Metropolitan Water Reclamation District of Greater Chicago (MWRD) as the stormwater authority for most of Cook County along with the Lake County Stormwater Management Commission, which has this authority for the portion of the Chicago River watershed that flows through Lake County.

As part of this mandate, the MWRD was required to create a new watershed management ordinance  which regulates site-based stormwater management. After years of effort and advocacy on our part, we are pleased to announce that as of May 1, 2014, the ordinance is in full effect!

Known as the Cook County Watershed Management Ordinance, or WMO, the new ordinance establishes standards that regulate stormwater run-off throughout Cook County.  The new standards require that future developments treat and manage the rainfall that collects on their site in a way that protects our streams and wetlands and reduces flooding.  To assist developers and municipalities in understanding how to implement the ordinance, a Technical Guidance Manual was developed to serve as a companion document to the WMO. The Guidance Manual provides detailed information, methodologies, and examples to explain how compliance with the rules and regulations set forth in the WMO can be achieved.

Why was the WMO Needed?

The WMO was needed because over the last 150 years, across the Chicago River watershed, we have paved over the natural landscape or built buildings on most of the open space where water used to seep into the ground. Then, to control that water, we treated it like garbage and piped it to our sewer system where it carries runoff pollution with it and causes combined sewer overflows, polluting the Chicago River. In addition, that once-clean stormwater pollutes rivers all the way downstream to the Gulf of Mexico where it contributes to the hypoxia, or dead zone. The massive amounts of extra water in the sewer and river systems also causes flooding. In the absence of a WMO, significant portions of the county could be developed without addressing the impacts of stormwater runoff on the people, plants, and animals that live downstream.

The WMO better protects wetlands and streams which provide vital habitat for fish, wading birds, ducks, beavers and other wildlife and places where residents fish, boat, canoe, kayak, picnic and enjoy the outdoors. It also provides stormwater management controls that will reduce flood damage to homes, roads, and businesses.

For more information, see news: April flood reveals Chicago's Achilles tendon.

In Summary the WMO:

• Protects remaining Cook County wetlands
• Promotes green space that will protect and improve water quality and provide wildlife habitat
• Promotes the use of green infrastructure to help rainfall soak into the ground
• Minimizes negative impacts of development in flood-prone areas

Green Infrastructure

Another and very important solution for addressing stormwater is green infrastructure. Recognized nationally as one of the best ways to manage stormwater, green infrastructure technologies have multi-tiered benefits including:

• Keeping water within our watershed
• Protecting clean water
• Recharging our aquifers
• Reducing CSOs and flooding
• And providing wildlife habitat and opportunities for outdoor recreation

Green technologies are cost-effective, sustainable, and environmentally friendly; and they capture and reuse stormwater to maintain or restore natural hydrologies.

At the largest scale, the preservation and restoration of natural landscapes, such as forest preserves, floodplains and wetlands, are critical components of green infrastructure.  On a smaller scale, practices can include rain gardens, porous pavements, green roofs, trees and tree boxes, and rainwater harvesting for non-potable uses.

In short, these technologies effectively absorb stormwater and keep it out of the overtaxed, man made, system of pipes and reservoirs.