Title

City of Evanston, IL 1909 Raw Water Intake Replacement

Document Number

N2021007

Document Type

CATEX

Project Description

The City of Evanston currently has three active intakes that supply raw water from Lake Michigan to the Evanston Water Treatment Plant (WTP), each of which draws water from between 5,000 feet and 6,000 feet offshore. Two of the intakes were constructed in the 1970s and consist of buried concrete pipes with diameters of 48 inches and 54 inches, installed in marine trenches with approximately five feet of cover on top of the pipes. The third intake, which needs to be replaced, was constructed in 1909 and consists of 36 inch and 42 inch diameter cast iron pipes that lay on the lakebed. The 1909 raw water pipe and intake structure have exceeded their intended design lifespans. Over the years the City has performed routine inspections and maintenance of the intakes, and has recently observed a decrease in flow capacity from the 1909 intake. In order to maintain treatment capacity at the WTP for decades to come, the 1909 intake pipe and structure need to be replaced. Replacement of the existing 1909 intake will require construction of a new intake structure and pipeline, in addition to onshore modifications to connect to the Evanston WTP. The new intake will consist of 60 inch diameter prestressed concrete cylinder pipe with a submerged, upturned cone inlet structure located approximately 5,500 feet from the WTP shoreline (60 inch Intake). The 60 inch Intake will be located near the alignment of the 1909 Intake. Construction of the proposed 60 inch Intake will be performed by a combination of offshore marine open-trench, nearshore marine open-trench, and coffer dam construction methods. The intake replacement project is at the 90 percent design phase, with the beginning of construction planned for early 2022.

EPA Region/Headquarters Office

OW

State or Territory

IL

Point of Contact

Leslie Temple
202-564-4734
temple.leslie@epa.gov

Date of Issuance

2021-10-14 00:00:00.0

Website

https://www.epa.gov/wifia