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No Easy Fix for Elmhurst Flooding

Burke/RJN team share findings for five areas hit hard last summer.

Nobody ever said fixing Elmhurst's flooding problems would be easy, and outside engineers July 18 presented a number of difficult choices the City Council will have to make.

Christopher Burke of Burke Engineering and Alan Hollenbeck of Wheaton-based RJN Group discussed their four months of research during this week's City Council meeting. They identified Elmhurst's flooding woes, as well as preliminary solutions.

Hollenbeck handled sanitary sewer research.

RJN teams monitored spring rains and did flow testing. They looked for areas the sanitary pipes interact with the storm sewer system, which allows the inflow of “clear” storm water to be unnecessarily processed by the sanitary system.

Hollenbeck discovered an "average peaking factor" of 15, 18 and 25 for north, southwest and southeast Elmhurst, respectively. Peaking factor is the ratio of the maximum flow to the average daily flow in a water system. An average peaking factor greater than 10 indicates a "severe problem." High inflows and infiltration of clear water into the sewer system in southeast Elmhurst led to basement backups that plagued southwest Elmhurst last summer, Hollenbeck said.

and clean check valves are two options Hollenbeck suggested for those residents who experience sewage backup in their basements. The city offers a subsidy for overhead sewers, which Hollenbeck admitted are "a very expensive and a disruptive type of construction"; a clean check valve is an alternative for those unable to install an overhead sewer. (See slides 18-25 in attached presentation.)

Another problem in south Elmhurst is older homes with foundation drains directly connected to the sanitary sewer. Burke said any home built before 1968 likely has this type of drain, which is expensive and cumbersome to dig up and disconnect.

Burke added that 64 houses in southwest Elmhurst, alone, have reverse-slope driveways, which is another flawed trait of the city's older housing stock.

"If we were able to develop Elmhurst the way we would like it to be built today, knowing everything we know about stormwater management, we would probably not recommend … reverse-slope driveways," he said. "We would design these areas a lot different."

Retrofitting Elmhurst to mitigate flooding could be a difficult proposition as well. Burke outlined some possible solutions that require construction of thousands of feet of relief sewer, and possibly converting green spaces, such as York Commons Park, into a water storage area.

Burke did not have costs associated with such improvements, but he did admit his preliminary alternatives would be far from fool-proof. For example, the area of Vallette Street and Swain Avenue would still only have a “five-year-storm level” of flood protection after any proposed improvement is completed. A five-year storm refers the level of storm intensity likely to happen once every five years.

And even those solutions would only be possible if the city can convince other bodies, such as District 205 and the Elmhurst Park District, to use their properties for water storage. Aldermen said Monday that local taxing bodies are aware of the suggestions that may come from Burke's comprehensive plan on flooding.

"We have not only whispered in their ear, we have screamed in their ears ... that these are potential solutions that may be coming forward," 6th Ward Alderman Jim Kennedy said.

Burke said another option, buying out flood-prone homes in low-lying areas prime for water storage, has not yet been considered, but he didn’t rule it out.

The outside consulting team will continue to study the situation throughout the fall before making a final presentation of the comprehensive plan for flood mitigation and associated costs in November.

Fifth Ward Alderman Chris Healy said the reality of the situation is the city has to keep the water out.

"This information shows us that the problem isn't what to do with the water. The problem is, how do we stop the water from getting into the system?" he said Monday.

"The bottom line is, when Mother Nature wants to win, she's going to win."

Jim Court July 21, 2011 at 07:13 PM
I have often wondered if we couldn't dig up a street, create a large box like structure, similar to a large basement and then overlay it with flexicore concrete, such as used in parking garages. In effect, we would create a large water retention area and not disrupt the aesthetic of the area or need to create retention ponds. Retention ponds are difficult to do in an area that is already built out. We do need solutions and we need them now. We cannot pontificate forever. We can disconnect all gutters immediately, which would take a huge burden off of our system. Paralysis of analysis will not prevent traumatic flooding that happens during heavy rains. We must act decisively and seek the best results we can while seeking the highest return on investment and the simplest solutions first. Absentee ballots are pourrrrrring in for my 8th Ward candidacy.
Jim Court July 23, 2011 at 05:50 PM
Bob, You obviously have given this a great deal of thought and have written a very analytical and comprehensive response. I did not think that it would have been prohibitive from a financial perspective to dig up a street, place precast concrete, and create a huge retention area. Perhaps I am wrong about the costs. I am concerned that we must seek solutions as soon as possible. I am sure that everybody thinks the same way about this. We cannot be know as a town that floods continuously or that suffers from an unstable power supply. What would be the first step you would take to help mitigate the problem? Thank you for your response.
Darlene Heslop July 23, 2011 at 06:19 PM
if you had taken the time to listen to the presentation by mr. burke, which i highly suggest you watch as it is very informative, you will find out that part of the proposed mitigation is creating detention areas w/gravity drains in them, both "upstream" and "downstream" as well as expansion of some area's storm water pipe system to include parallel pipe that would create extra "storage" for the stormwater, rather than flooding the streets. however, the first thing i would do is a disconnect program of the downspouts and back yard drains...easy, simple, cheap.
Jim Court July 23, 2011 at 06:55 PM
Darlene, Where do I find the presentation? I agree that disconnecting the downspouts should be the first effort taken.
Bob Santini July 24, 2011 at 02:43 PM
i agree w ms heslop that downspout disconnect is easy and cheap; however, i'm not sure that it will be well received by the folks who are forced to do it; keep in mind that many, if not most, of these "newer" homes were not "designed" by green architects/developers. in other words, there's not a lot of permeable area for the rainwater from a disconnected downspout to be absorbed into; so the water is going to end up in the same place (the street). imo, the first thing the council should do is pass legislation that requires a lot owner (for new housing) to capture a certain percentage of the rainwater from their roof on their own property. in the old days, most municipalities limited a building's footprint to a certain percentage of the lot size (called Floor Area Ratio "FAR"). whereas now, the primary limitations are affluence and set back lines. unless this is done, all the new homes going up are just going to add to the existing problem of capacity vs. inflow. i applaud the report for showing a rain garden as an example. however, certain areas of town, notably the southwest, have problems that dwarf the rest of town. unless we are allowed by DuPage County to send more water into Salt Creek (which ends up in the quarry), there is simply not enough park/school/vacant land that is downhill to insure that the SW area of town will be safe from a 100 yr. rain.
Jim Court July 24, 2011 at 03:11 PM
Bob, Is the quarry elevation such that water would flow into it from the southwest portion of town? It would seem to require the water to flow upstream and to a higher elevation. Is there any existing area that would allow for the creation of another quarry in southwest Elmhurst? It seems that we need another reservoir that is situated closer to the area of flooding. You and Darlene have studied this more than I have so bear with my questions. Could we deepen salt creek and install some form of a damn that could be opened and closed to control waterflow? There must be a viable solution that could be implemented as soon as possible. The rain in DesPlaines suggests that this is an ongoing and eminent problem. The 100 year old model may no longer apply.
Dan July 24, 2011 at 03:15 PM
The City doesn't control the quarry the county does.
Jim Court July 24, 2011 at 04:41 PM
Could we create our own quarry, controlled by Elmhurst? Could it be created by selling off mined materials and outsourced to the current operators of the existing quarry? Excuse me if I color way outside the lines but we need to consider all ideas and proposals.
Darlene Heslop July 25, 2011 at 04:14 AM
on the city website you can view the presentation on tape from the city council meeting. or...you can view on channel 6 the city council meeting at 12 noon on wednesday or 7 pm on thursday.
Darlene Heslop July 25, 2011 at 04:29 AM
nice mr. o'malley...a little bit of sarcasm sometimes does help to lighten the mood. one thing that mr. court and others don't understand is the purpose of the quarry. the quarry exists in order to create a resevoir for creek overflow from north of elmhurst so that it doesn't flow down and flood us, therfore, keeping enough capacity for elmhurst to have some volume in the creek in order to accomodate its run off. damming the creek will not solve any problems, only create more. fact of the matter is this...as difficult as this is for the people of elmhurst to comprehend, this town was overbuilt on land that essentially, 150 years ago, was nothing but marshland and underwater most of the year. building more streets, bigger homes, schools, retirement home villages, putting artificial turf on the football field, and not expanding existing stormwater sewers - have created this problem that now we have to somehow go back and figure out how to fix, when the bottome line is...what we need, pure and simple, is more places that mother nature can put what mother nature dishes out to us in the form of rain...sometimes a lot of it at one time. so...if what we are not faced with is needing to dig really big, really deep holes in the ground, both upstream and downstream in order to mitigate this problem, then you know what, we have to do it. and if we need to disconnect the downspouts and yard drains from the stormwater system, then we do. end of story folks.
Dan July 25, 2011 at 05:59 AM
There is information and products for harvesting rain water at www.conservationtechnology.com. It would be interesting to determine the difference in cost to install a rain gutter and sump pump water storage system for a home vs. connecting the same home to the city stormwater system. These systems are more sophisticated then a rain barrel and allow you to store more water and then use it for irrigation during dry spells. Although I appreciate the knowledge and experince that a firm like Burke Engineering brings to the table one would think that we could work with some of the excellent engineering schools in Illinois through an intern type study program creating a costs benefit analysis into handling stormwater on a smaller home by home approach vs the current system of connecting homes to the public storm water system. You would think that at some point our current system couldn't handle one more home without creating a bottle neck problem costing a small fortune to fix.
Jim Court July 25, 2011 at 01:14 PM
Darlene, I have not studied this as thoroughly as you but I was under the impression that the quarries stored water that originated upstream and that would overwhelm Salt Creek. I also thought that it did nothing to address all of the water that directly fell in our community. I thought that is why the concept of water retention based in our community seemed valid. I agree that disconnecting downspouts should be the first order of business. I also liked the idea of utilizing interns as a means to address the problem in a cost efficient manner.They could also adopt the best practices that other communities have utilized. A friend of mine actually blocked the clay tile that poured water into his sump pit. Although the foundation probably has greater hydraulic pressure since he is not eliminating the water from the high water table, he has experienced no seepage and seems to have mitigated the potential for his basement flooding when power goes out. His sump pump ran continuously and all he was doing was sending water outside to eventually filter back into the sump pit and endlessly pump water out.
Bob Santini July 25, 2011 at 01:58 PM
also keep in mind that there were many flooded basements in homes that are NOT even connected to the storm sewers (esp in your ward darlene); these homes were flooded by sanitary water backflow that somehow got intermixed with an overburdened storm system; so if you really want to get elected in the 4th ward, besides helping the poor folks on Pine Street, you might want to drive around your ward and notice how many homes are actually connected to the storm water system (not very many; just the ones built in the last 10-15 years); and yet hundreds of these homes were flooded with sanitary backup from floor drains. rain barrels, sisterns, and gray water systems are a nice concept, but really, people want government to solve their problems, without any increase in their tax bills; and don't forget to plow my streets in the winter !
Darlene Heslop July 25, 2011 at 06:44 PM
i am aware mr. santini of the problems facing the residents of the fourth ward, in particular, those on the far east side of the ward and in the bryn haven sub division. their flooding problems are different in nature, and burke and company have yet to finish their report and recommendations as to how to mitigate the situation in these areas, which, i look forward to seeing. i know that last summer the city council, including our current aldermen, voted in support of additional funding for the overhead sewer program believing this to be a solution, almost the solution, with the mayor practically baiting burke to say so. i didn't agree and it turns out that rjn's findings support this. what needs to be done in order to prevent back flow of the sewage from the "old" combo sanitary/stormwater system, is disconnecting what is there that is contriuting to the increased volume during rain, which, at the present time, they don't exactly have a recommendation as to what to then do with this water (which i have asked the task force to look into for me since i think it is logical to have an answer for this question). i want you and others to know that i am trying to find whatever are the easiest, cheapest, fastest ways to mitigate this situation, at least in our ward.
Adam July 26, 2011 at 12:19 AM
well I had a sewer backup on Saturday morning.. for the 2nd time this year... I love my neighborhoods sewer main! MM MM good stuff
Jim Court July 26, 2011 at 01:31 AM
Adam, Is this a case of "forbidden fruit"
Bill Angel July 26, 2011 at 03:43 AM
Mr. O'Malley, it's Flintstones, Fred and Wilma. Don't forget to mention Bernard "Barney" AKA "King Peter" Rubble who will assist wit da fixen of da pipes an dat youz know. I gots a guy. "Er huh huh ok.
Darlene Heslop July 26, 2011 at 11:29 PM
mr. angel, i have to confess...there are times that i can't believe how right on you are...and a budding comic to boot.
Bill Angel July 27, 2011 at 01:46 AM
Ms. Heslpo, I won't quit my day job. TIF, TIF, TIF, Economic development, Economic development, flooding, flooding, flooding. Da utter communities arz dooen it. Monkey sees monkey does. TIF TIF TIF
Darlene Heslop July 27, 2011 at 04:10 AM
never said ya should. we need you on our side.
Jim Court July 27, 2011 at 11:58 AM
I am not so sure that it is constructive to mock the Mayor. It is okay to disagree but negativity detracts from our community and the demeanor of these pages. It may ultimately cast people as negative complainers and create an underdog status which can ultimately strengthen the person being criticized. I also believe that some sensitivity needs to exist as these people have family, friends, and children and would not like to read comments that are so negative.. No one is all bad and in the case of the Mayor we are not talking about someone evil, just points of disagreement. I am sure I would have my detractors if I were an elected official. I would hope they would disagree in a manner of respect. I never want to be a narcissist or know it all. The more I know the more I realize how little I know. I like Elmhurst and only want to see it improve.
Bill Angel July 27, 2011 at 06:49 PM
Mr. Court, Why do you defend a person who is full of himself and has not fulfilled a single campaign promise to date. When you become a public official you are fair game. I want what's in the best interest of Elmhurst and it's taxpayers. Every time I turn the corner this guy is spending (SOP) money on some consultant or wants to raise my taxes or fees. The words you use and how you speak has meaning. If you can't speak properly or can't think on your feet, get a tutor or tele-promter. Sound familiar? I know what I know, I know what I don't know, Big picture for Elmhurst...where are his written goals, vision, objectives, projects, and actions towards improving the city I love? Ask him yourself at the next City councio meeting. Watch the dance!
Darlene Heslop July 27, 2011 at 07:27 PM
mr. court, have you ever watched steve colbert? he would have a field day if he lived here, with the way the elected officials behave and talk as well as the way things are run around here. we have a couple of "steve c's" right here in elmhurst, which actually bring a lot of information and break up the monotony around here. and btw, if we didn't have the quarry, we would flood every single time there was a big rainstorm north of us, since water runs downhill, their run-off would then become our flooding problem - so, in essence...the quarry is being used to mitigate flooding here in elmhurst - that which would occur if we did not have a place for salt creek to go (recall what happened in 1987??). look at a map of salt creek then tell me where the run-off from north of us was going to be if not for the quarry...in the basements and streets of elmhurst and oakbrook residents.
Tina Tuszynski July 27, 2011 at 08:08 PM
Darlene, wouldn't that be funny? Perhaps we should extend an invite to Colbert & Jon Stewart to broadcast from a local community, kind of like their road trip last summer. With all the emphasis on community journalism, it could be interesting!
Darlene Heslop July 28, 2011 at 03:48 AM
oh yes...very interesting indeed... .

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