Expanding Buffalo Creek Reservoir

June 2, 2021

Recent work by the Metropolitan Water Reclamation District of Chicago is increasing the reservoir's capacity to nearly 60 million gallons

About the author:

Allison Fore is public and intergovernmental  affairs officer for MWRD. Fore can be reached at [email protected]. Patrick Thomas is public affairs specialist for MWRD. Thomas can be reached at [email protected].


The Buffalo Creek Reservoir in the Lake County Forest Preserves (LCFPD) north of Chicago near Buffalo Grove, Illinois, has a fresh, new look and feel thanks to the Metropolitan Water Reclamation District of Greater Chicago’s (MWRD) work to increase the reservoir’s capacity by nearly 60 million gallons.

Also improved is the reservoir’s setting. Now teeming with natural prairie and wetland plants to absorb more water, it has more capacity to protect neighboring communities from flooding.

A History of Growth & Expansion

From 1960 to 2000, the population of Buffalo Grove grew from 1,500 residents to nearly 43,000. Like so many communities and Chicago before it, Buffalo Grove was grappling with new waves of residents.

In 1973, the MWRD, the LCFPD and the Village of Buffalo Grove entered into an agreement to acquire the land and construct the original Buffalo Creek Reservoir. The project was intended to provide flood protection for the rapidly developing communities of Buffalo Grove and Wheeling that were downstream of the Buffalo Creek. The original reservoir’s construction was completed by 1983, and the volume was expanded in 1988. But work was far from complete.


Comprehensive Planning & Partnership

The risk of overbank flooding remained for communities downstream within the Lower Des Plaines River Watershed. The watershed impacts 1.5 million residents living in 77 communities, along 308 miles of streams. The watershed stretches across 491 square miles through three counties west of Chicago. In assessing how to reduce flooding, the MWRD published a study in 2011 identifying another reservoir expansion project along Buffalo Creek and along the main stem of the Des Plaines River.

Coincidentally, the LCFPD had also been considering improvements at the forest preserve to expand trails and parking at the preserve. They reached out to the MWRD and the two agencies agreed to work together to construct the public access improvements while incorporating MWRD’s planned reservoir expansion. Through this collaborative process, and in partnership with the Village of Buffalo Grove, the design combined public access improvements, enhancement of the preserve’s natural features and expansion of the reservoir’s volume. Under the terms of an intergovernmental agreement, the MWRD agreed to cover the costs of the $9.7 million project, while the LCPFD is responsible for future maintenance.

The U.S. Army Corps of Engineers (USACE) estimated that the additional storage will reduce future flood damage by $26 million.

“We deeply appreciate the MWRD continuing to lead this process,” said USACE Army Colonel Aaron W. Reisinger at the May 2, 2018 groundbreaking ceremony. “It’s super important to get as much storage as we can in the Des Plaines region.”

The project’s boundaries make the Buffalo Creek project unique. The reservoir lies north of the MWRD’s service area in Lake County, but the expanded storage benefits Cook County communities affected by flooding. An estimated 107 structures will be protected from various flood recurrence intervals and more than 2,000 structures along Buffalo Creek, and the main stem of the Des Plaines River will receive some form of flood reduction benefit.

“We appreciate that our counterparts in Lake County are engaged in this partnership to help relieve flooding on the Cook County side of the border,” said MWRD Commissioner Mariyana Spyropoulos. “Flooding doesn’t recognize boundaries, so it makes economic sense to work together so that residents living in the area receive benefits, whether they enjoy the Lake County Forest Preserves as an amenity or as a storm water management tool.”

Less Storm Water, More Clean Water

The myriad benefits will have a positive impact on the environment.

“Collecting more storm water will result in cleaner water and a healthy environment for the 1.5 million people living in the watershed,” said MWRD President Kari K. Steele. “This work represents a long tradition of service that the MWRD has provided over an evolving history of technology, population and climate change.”

Created in 1889 as the Sanitary District of Chicago to reverse the flow of the Chicago River, the MWRD today is an award-winning, special-purpose district responsible for treating wastewater and providing storm water management for 5.25 million residents and businesses across 882.1 square miles, which includes Chicago and 128 suburban communities.

As the protector of water resources, the MWRD continues to transform wastewater into clean water and protect the health and safety of citizens, area waterways and Lake Michigan, the local source of drinking water. In its mission, the MWRD also strives to protect businesses, homes and neighborhoods from flood damages.

Since receiving authority from the state of Illinois to invest in local storm water management projects in 2014, the MWRD has expanded its many projects to meet the rising demand of flooding concerns. Between, local and regional storm water management projects, green infrastructure partnerships and flood prone property acquisitions, the MWRD has more than 170 projects in some phase of design or construction, and the totality of these projects are protecting or removing more than 13,000 structures. Still, there is more work to accomplish.

Expanding Buffalo Creek Reservoir

After engaging design consultants from Hey & Associates and selecting Lake County Grading Company as contractor, the MWRD officially broke ground on the project in 2018.

MWRD set out to increase the flood volume by 180.7 acre-feet, expand the open water area by 6.3 acres, the wetland area by 14.8 acres and grow new plants in an emergent zone area enlarged by 4.5 acres. To expand the reservoir’s volume, 300,000 cubic yards of material was excavated and trucked to create hills west of nearby Schaeffer Road.

Most of the reservoir needed to be dewatered for construction purposes. The west portion of the existing 755 acre-feet reservoir (246 million gallons) was drained to excavate in dry conditions. Crews created a haul route and diversion ditch and went to work on removing an island and lowering the west pool of the reservoir by demolishing an old gabion drop structure.  To keep the preserve open for public access, temporary trails were phased into the work while building new trails and boardwalks were simultaneously constructed. Of course, emptying a reservoir can also lead to unforeseen revelations. During construction, engineers observed that articulated concrete block (ACB) erosion control around the perimeter of the dam’s energy dissipation pool needed repair, so plans were made to expand on the original contract replacements.

North and west of the reservoir, the MWRD improved 400 lineal feet of the main stem of Buffalo Creek and more than 1,200 linear feet of the West Unnamed Tributary, respectively, with selective clearing, grading banks, riffle enhancements and native vegetation. As part of the project, 23 acres of upland prairie west of the reservoir were restored and a new grade control structure was created with the installation of sheet pile and rip rap to stabilize Buffalo Creek Tributary as it enters the reservoir from the south. Another stone grade control structure was also installed on a minor tributary entering the west portion of the reservoir.

The site was restored with native prairie, terraced wetlands and a naturalized shoreline. In total, 850 trees and 200 shrubs were planted.

Many of the forest preserve amenities worked in tandem with the storm water capacity improvements. With rising flood waters, the MWRD had to relocate and reconstruct several portions of pedestrian trails and account for periodic flooding when constructing new boardwalks. Once completed, the MWRD raised or constructed more than two miles of multi-use trails and seven wooden pedestrian boardwalks, along with two pedestrian overlooks and a 30-space parking lot expansion.

With the project complete, Buffalo Grove President Beverly Sussman, who settled in the community approximately 50 years ago, sees a major improvement.

“This project represents a long-standing relationship and ongoing cooperative effort between the village of Buffalo Grove, the Metropolitan Water Reclamation District of Greater Chicago and the Lake County Forest Preserve District, which began back in 1973,” said President Sussman. “Through the cooperative efforts of the parties, the effects of flooding on our respective communities and regional stakeholders will be reduced. The completion of this project will further reduce the risk of flooding and provide a safe and healthy environment for many years to come.”