Web Extra! The IDNR’s Groveland Avenue Study and see satellite views of proposed solutions.
The Illinois Department of Natural Resources has released its study of possible flood-control solutions in Riverside, four months after it was completed.
The Groveland Avenue Limited Strategic Study outlines seven alternatives for controlling flooding in the neighborhood bounded by Park Place on the north, Forest Avenue on the south, the Des Plaines River on the west and Kimbark Road on the east.
The study followed on the heels of discussions last year between the IDNR, the U.S. Army Corps of Engineers, village officials and an organization called Riverside Residents for Flood Prevention.
The Army Corps of Engineers is conducting its own, farther-reaching, Des Plaines River study. The IDNR study completed in October 2009 focuses on Riverside specifically.
“I think it’s very encouraging,” said Richard Rankin, a Groveland Avenue resident who serves as the spokesman for the Riverside Residents for Flood Prevention. “Until now, there has not been a study specifically done in the area.”
Village President Michael Gorman received the study from the IDNR in February.
Asked by phone to comment on the study, Gorman demurred and e-mailed a response that highlighted his political party’s commitment to the effort.
“The Riverside Community Alliance pledged to advocate for our residents who are impacted by Des Plaines River flooding,” Gorman wrote. “There is a significant cost to the village whenever flooding occurs. As we have done since our election in April 2009, we will continue to partner with the Illinois Department of Natural Resources, the Army Corps of Engineers, the Metropolitan Water Reclamation District, and the Riverside Residents for Flood Prevention in order to pursue avenues for addressing the hardship suffered by Riverside residents.”
He did not comment on the flood prevention measures outlined in the report or the prospect of any of those measures coming to fruition.
The study followed in the wake of a storm in September 2008 that raised the level of the Des Plaines River in Riverside to nearly three feet over flood stage. Water never topped the 900-foot-long berm along Groveland Avenue, but rushed in from a low-lying area north of Park Place.
The flood waters inundated roadways and the basements of homes along Groveland, Lincoln and West avenues, forcing hundreds to evacuate until the water subsided.
The IDNR’s report pinpoints one particular choke point on the river in Riverside – the Burlington Northern-Santa Fe railroad bridge south of Forest Avenue. The tracks angle off toward the southwest across the river, and the concrete piers supporting the tracks are perpendicular to the tracks, not the river.
As a result, the piers block 33 feet of the river instead of the 6.5 feet that would be blocked had they been aligned with the river’s flow in mind. Realigning the piers would reduce flood levels by almost a foot, according to the study.
Adding culverts through the earthen railroad embankment west of the river could also aid flood water going south, the report states.
Realigning the bridge piers, however, would require the full cooperation of the railroad, which would likely experience service interruptions to complete such a project.
The study provides for an alternative to building new piers by extending the ones already there to facilitate the flow of water under the bridge. Such a plan would require widening the river banks both north and south of the bridge, increasing the bridge span by nearly 50 feet.
Outside of railroad bridge modifications, the study imagines two possibilities for raising and extending the existing Riverside levee east along Park Place to Woodside Road and south of Forest Avenue to the railroad right of way to protect the Groveland/Lincoln/West area from flooding.
Such a plan, however, would require the demolition of some boat houses south of Forest Avenue and could run into private property issues along Park Place. The plan also doesn’t consider the affect such levees might have on properties north of Park Place adjacent to the river on Maplewood Road.
The study also suggests the possibility of blocking the river flow from Salt Creek during flood events. However, as the study notes, such a decision would likely worsen flooding west of First Avenue, an area also hit hard by flooding in September 2008.
A final proposed solution calls for removing the Hofmann Dam, something that has been talked about for decades but has never moved forward because of the cost. However, removing the dam would have little effect on flooding, according to the report.
“The railroad bridge modification alternative created the greatest reduction of water surfaces for the project area and reduces potential debris buildup,” the report concluded. “However, this alternative has little effect on increasing the level of flood protection to the Groveland Avenue floodprone area. Only the levee alternatives show a substantial reduction in flood risk.”
The report gives no cost estimates for any of the projects. The Army Corps of Engineers is conducting its own, wider-ranging study of Des Plaines River flooding. The Riverside Residents for Flood Prevention is trying to schedule a public meeting with the Corps in April, said Rankin.
Loren Wobig, project manager in the IDNR’s Office of Water Resources’ planning division, said that the Groveland Avenue study was forwarded to the Army Corps of Engineers, who will use it as part of their study of the Des Plaines River watershed.
The Army Corps of Engineers will do a cost-benefit analysis of projects that will reduce flooding and prioritize potential solutions to see if there’s interest in spending federal dollars to make them happen.
“If there is then we’d end up in a cost share with them to implement those,” said Wobig. “If not we could work directly with communities on some sort of cost-sharing arrangement.”
Implementation of any project is likely many months if not years away. But residents affected by flooding in Riverside are glad their concerns have the ears of state and federal agencies.
“At least they’re shining a light on it,” said Rankin of the studies. “It always comes down to the money and the political will.”