Construction is set to begin next month on a $1.7 million project to decrease flooding on the northwest side of Lombard by making long-awaited improvements at Terrace View Pond.
A pumping system will be installed to lower the pond's water level during dry conditions, increasing its capacity by 4.2 million gallons during periods of heavy rain. In addition, two relief sewers will be constructed between Crystal Avenue and the pond.
Lombard's public works department outlined the construction plans and their expected benefits to about 50 residents Thursday night, saying the improvements will allow more stormwater to enter the pond instead of backing up on streets or in basements.
The plan was designed to decrease flooding on Crystal Avenue immediately north of the pond because it is the lowest street in the 240-acre area that drains into the pond, Public Works Director Carl Goldsmith said.
"Any effect on Crystal will have an ancillary benefit on the neighboring streets that flow into Crystal," he said.
The relief sewers and additional pond capacity will have the greatest effect during intense but short-lived periods of rain, such as a storm dropping 1 or 2 inches of rain in an hour.
During storms as long-lasting as the rains that flooded the area April 17 and 18, however, even the upgraded system will not keep up.
"It'll provide a certain degree of relief," Goldsmith said. "These improvements will not resolve all issues in all types of storms, but we will be doing what we can incrementally."
Construction of the Terrace View Pond project is scheduled to begin June 17 and conclude around Halloween, but the plan has been in the works since the aftermath of a flood in July 2010.
The village first commissioned a $52,000 study to determine the best way to improve stormwater management in the area, then sought and received Lombard Park District's permission to lower the water level one foot.
The project will result in a loss of wetland plants as water will recede between three and five feet from the current shoreline, but native vegetation will be planted in the newly exposed area.
The next stormwater project on tap in Lombard will be the $6.5 million replacement of a pumping station on Route 53, with the new one sending water along sewer lines three times faster than at present.
Goldsmith said his staff is developing other plans to address flooding problems residents experienced in April, and those ideas will be presented to the village board's public works committee in the coming months.