GLEN ELLYN – The Village of Glen Ellyn has taken another step to address Lake Ellyn flooding, beginning the design process for increasing the output rate of water from the lake.
The lake currently drains at 37 cubic feet per second, but based on the recommendations of a Lake Ellyn drainage study, the village is seeking to increase that amount to improve the lake's performance during a serious storm event, like the one the area saw in April.
Water drains from Lake Ellyn through an outlet structure at the north end of the lake into a storm sewer under Riford Road. The sewer brings it to a channel betwen 725 and 717 Riford Road and heads to Perry's Pond, eventually reaching the East Branch of the DuPage River.
Proposed modifications to the Lake Ellyn outlet control structure include increasing the structure's weir length by 8 feet and expanding the structure's opening into the drainage pipe from 24 to 31.5 inches.
These changes would increase the lake's discharge rate to 61.4 cubic feet per second, or about 40 million gallons per day, according to village reports. That is the maximum rate allowed by DuPage County based on the size of the Lake Ellyn watershed.
However, Glen Ellyn may be able to increase the discharge rate further, depending on pipe capacity, effects on downstream areas such as Perry's Pond and available room in the DuPage River's East Branch, according to village reports.
The Glen Ellyn Village Board voted unanimously June 24 to approve a $59,000 agreement with RHMG Engineers for design engineering services for the proposed modifications to the outlet control structure and FEQ modeling assistance to determine impacts on other bodies of water in the area.
The proposed timeline from RHMG, which is the firm that performed the village's Lake Ellyn drainage study, includes a June 2014 construction completion date for modifications to increase the lake's discharge rate beyond 61.4 cubic feet per second, according to village reports. The outflow would be increased to 61.4 before that.