The Wilmette Pump Station was constructed around 1909 and includes a lock that separates Lake Michigan from the North Shore Channel (NSC). The pump station is owned and operated by the Metropolitan Water Reclamation District of greater Chicago (MWRDGC) and is used to control the water levels in the NSC and improve water quality by allowing inflow from Lake Michigan. CTLGroup preformed an evaluation of the exterior reinforced concrete walls of the NSC and lock that exhibited visual evidence of degradation. The objectives of CTLGroup’s work were to assess overall condition, evaluate concrete quality and durability, evaluate cause of deterioration and provide conceptual repair recommendations.
Findings from the evaluation indicated that channel walls generally exhibited extensive deterioration above the waterline that is attributed primarily to freeze-thaw exposure. Concrete below the waterline exhibited only minor deterioration. Findings from examination of core samples extracted from the walls indicated that partial depth repairs may be feasible to restore integrity of the walls and extend service life. However, additional sampling was recommended in order to better ascertain which remediation option (repair or replace) would be most cost effective.