Stormwater Commission

STORMWATER COMMISSION MEETING SUMMARY Wednesday, June 30, 2011 The following persons were present: Chairman Joe Lo Verde, Steven Vinezeano, Andrew Vitale, Mousa Nazzal, Richard Wlodarski, Scott Jochim, Fred Kudert and Jeff Wickenkamp/Patrick Lach of Hey and Associates. Chuck Ostman and Tom Polcyn were absent. Pam Defiglio of Patch.com was briefly in attendance. 1. Opening Comments: Vinezeano welcomed Fred Kudert as a full member of the Stormwater Commission. Tom Polcyn was not available to provide an update on the recent storm activity. 2. Approve Meeting Summary of Wednesday, April 27, 2011: Vinezeano provided the summary to members prior to the meeting. The summary was approved to be posted on the Stormwater Commission web page. 3. Old Business: a. Community Rating System Inspection. Discussion was postponed. 4. New Business: a. Flood Proofing Programs Presentation by Hey. “Local Flood Proofing Programs” handout and PowerPoint presentation given by French Wetmore who is known by Jeff Wickenkamp. The presentation provided examples of flood proofing methods that may be suitable for preventing flooding from overland stormwater flows in Niles for homes that cannot be considered for “buyout” and where there may not be any other cost effective solutions. The examples focused on simple “barrier type” methods such as foundation sealing, curbing and other forms of small dam like structures that could be constructed along the outer walls of the home. b. Modeling and Diagnosis by Hey. The engineering study and analysis of the East Sector (east of Milwaukee Ave.) is complete. Options to address the majority of the flooding issues in this sector have been developed including estimated costs and timing. They were presented through a Power Point presentation and recommendations were identified and discussed. Hey and Associates also provided an update on the status of Phase I work concerning the West Sector. The majority of their activity in this part of the program has focused on establishing the basic geography and overland conditions in this area along with details of the sewer system. With this information Hey has modeled the subsequent storm water flow patterns. Their first slide provided a “big picture” view that depicts how the terrain allows water to flow right through Sunset St. into the lower areas of Park Ridge. Hey stated these are very challenging issues because there is no overland outlet for the storm water and the sewer pipes are not large enough to take it away. Solutions in this area may be limited to above or below ground storage methods. Analyzing the West Sector requires direction from the commission to identify the specific sections, the worst areas of flooding, which need to be modeled and studied. Phase 1 West Study Area Exhibit. Patrick Lach of Hey walked the Commission through some general modeling of 100- and 10-year rain events. He discussed the intensity, duration, and inches of rain and the impact of these parameters on storm water flow in the sewer systems. Shorter duration rain events of 1” to 2”+ and two hours or less are the most critical as they are likely to cause localized street, home and basement flooding. He stated that even a 10-year storm is still likely to negatively impact the homes near Bruce, Lincoln, and Knight because of the Des Plaines River (West Basin) Problem Area. The table which summarizes the modeling of this area shows that there are structures which will be inundated during both 10- and 100-year rains. If a home is inundated, it means water reaches and touches a home via overland flow. However, the storm sewers appear to be adequate in size and basement backups are not expected to be a problem area on the West side. A question was asked whether or not a solution could be used for the Bruce area and the Sunset area. Even though the storm water from both locations goes to the same outfall it may not be possible to reduce the flooding because the water enters the areas from two different points. There was also discussion about the relationship between the property of Our Lady of Ransom Church and the runoff north to Sunset, and the efforts that have been considered and implemented to use portions of the Church’s property, the open field, for storm water retention. It was explained that Fr. Chris agreed to have the field deepened to allow more water to be retained. It can contain a 2.5” rain before it overflows west. Fr. Chris stated that Catholic Church leaders in the past did not want to build anything substantial at that location. It was mentioned that a curb was also suggested, but removing soil provided the same affect. This area will not provide any additional storage capabilities until the retention area is further modified and it is not clear if this will be allowed by the Church. Hey stated that Sunset is basically the lowest point in Niles as it leads to Park Ridge. Sunset is essentially a bowl retaining water however the Church property appears to be high and remains dry. An alternative will be considered for Sunset, but the use of underground vaults will be limited and there may be a need for use of nearby open land for additional storage capacity to properly address flooding in this area. On the east side you can increase the diameter of the sewers. This is not an option on the West side because the Park Ridge system, which the West Side connects to, cannot accommodate a twofold increase in storm water flow. It was also noted that water from the West Side of Niles flows into Park Ridge overland naturally and it is important that whatever Park Ridge does to help with flooding, that it does not stop this natural flow. It was also clarified that Illinois law would not allow them to do this. The Park Ridge proposal to use North Park for storm water storage was also discussed. While this proposal is on hold as of the date of this meeting, technically it appears that this storage concept would be mutually beneficial to both Niles and Park Ridge. Regarding specific West Side problems, Hey stated that the Bruce/Lincoln/Knight and Sunset areas are critical and they should be considered as a specific area for a detailed analysis. There were also questions about Roseview and the level of issues there. Again it is a natural low point that allows water to accumulate during flooding. This is considered the third worst area on west side by Hey and they recommend it be reviewed further. Sewers in area seem to be shallow, yet Cumberland sewers seem oversized with sediment that should be flushed more often or watched. The minimum slope for sewers and how this relates to sediment build up was also discussed. DPO1,2, 5,6,7 (8/9cursory look) were identified in the Des Plaines River (West Basin) Problem Area Table to be critical, requiring a detailed engineering review. A cost benefit analysis of possible storage alternatives will be developed but alternatives are limited by low grades and shallow slopes. The use of surface retention basins would require property purchases which are difficult to implement. For this reason, Hey generally does not consider this as a viable approach and it may not be included in their options. The Chair asked if initial complaints in this area (west side) involved basement flooding. It was explained that basement flooding from “backups” was not reported, but that some homes experienced enough surface flooding that water entered basements through doors and windows. There was a question whether or not some form of portable street barrier system would prevent some street to yard flooding to home flooding in extreme rains. In the brief discussion a definitive answer was not identified. The Chair asked about the Western sewer flow from Niles to Park Ridge and whether or not it is restricted. It was stated that sewers to Western are already restricted to 10”. Additional questions were discussed as follows:  1) What happens south to Western? Hey stated that they are doing a parallel study and Hey will contact Burke Engineering to coordinate the analysis of that junction. What is coming off of Niles and what is happening to the downstream pipe? Hey is currently assuming that they are full. 2) If the restrictor was removed, would it help? Hey stated that it is unknown, but it would most likely cause problems in Park Ridge. 3) There was a question concerning the possible use of the park at the southwest corner of North Terrace and Western Avenue for additional retention. This will probably not occur because of the discussion concerning North Park. However there may be some other viable storage possibilities for the area. Hey will investigate and report to the Commission at a later date. Surface storage at OLR is a possibility near Sunset and along Lincoln Avenue. There was discussion of how the Village did create an overflow storage basin at Lincoln in cooperation with the Church some years ago. However this was eliminated by back filling after a heavy rain because of public outcry of concern for the safety of children attending the Church school, which was in operation at that time. There was mention that if the northeast OLR property was ever up for sale, the Village should consider it for retention and possibly still allow it for use by the Our Lady of Ransom. Hey will need to see, from an engineering standpoint, if that is still an alternative for flood relief in the area. Regarding the Phase 1 East Study Area Exhibit, Hey provided preliminary alternatives in a recap of the 13 critical problem areas identified by the Commission, with recommendations. The levels of service goals used in the analysis were: 1) to prevent basement backups in the 10-year event, 2) prevent surface flooding of structures in a 100-year event and to also maintain vehicular street access for emergencies in a 100-year event. The cost for preventing basement backups is estimated at $40M to $45M or $9K per structure, however, many structures already have installed flood control and not all experienced flooding. Subsequently the per structure costs for those that have flooded are probably much higher. Hey also provided a Summary of Alternative Benefits and Costs with a cost per home breakdown for removing affected homes from a100-year storm. The Chair was concerned about the “cost per home” ranking because it is a community problem. Hey stated that if you want to rank alternatives by priority, you could do so by using the “cost per home” as a decision basis. It was repeated that the goal of the Commission was to eliminate “persistent” flooding and not necessarily prevent the 100-year flooding issues. Hey also discussed their recommended Early-out projects, Short-term and Mid-term projects. There was discussion that improvements which Niles chooses to implement will also probably benefit areas outside of the project boundary such as the Forest Preserve District and MWRD, and outfalls to the river. If sewer separation is added the number of CSO’s (combined storm and sanitary sewers) will be reduced. This is a potentially large benefit for MWRD and the river. Subsequently, the Forest Preserve District Commissioner for our area should be contacted soon to ensure there is a smooth process toward permitting. The Seward and Oakton Ct. area requires new relief sewers because it has a natural bowl geography and water does not leave it. Addressing this would also require coordination with the Forest Preserve District. And what if the Forest Preserve District says no? Hey stated that it is the only solution beyond buying homes and creating storage. Can we go north or south? No, because this area is lower than anything else and it may need to connect into the Oakton sewer. But Hey will look into the south option to intersect with the Oakton sewers in a manner similar to what happens at Harlem. If more water goes into the river, will it negatively impact Chicago River flow? Hey stated no and that it was very limited. There was a comment about Morton Grove property to the south and a possible easement. Nazzal will send them the easement information. Lee Street and Main Street. There was discussion about previously recommended storage relief for this area by using the cemetery, the Oak Park and the Notre Dame right of way. This would provide flooding relief by removing some of the volume. The Lee Street combined pipe would then be upsized and O street sewers would connect to it. The Jonquil and Dobson areas would also connect with a pipe for flow to the river by using golf course Park District Property. There was a question of whether or not sewers going to the river could backup and flood houses and Hey stated no. There are also three areas by Ottawa/Kedzie, Lawler/Oketo/Jonquil, and Ozark/Monroe that are not recommended for incorporation into a general correction plan due to costs per house. These three areas will need to be addressed on an individual property basis. What is going to happen next and how might we move forward to the final recommendation? Hey provided a PowerPoint showing program elements. They showed regulatory, system maintenance, capital improvements and cost share programs, all of which could be part of a final comprehensive Storm water plan. Hey showed recommended cost share programs and possible budget costs for flood control systems, flood proofing, and green infrastructure. Adding Green infrastructure to individual homes and other properties is likely to take time to implement, but during short duration storms, there is a tangible benefit. If there are people willing to do this, the benefit is there and the affect is cumulative. Subsequently, green infrastructure approaches could be considered in the program. The remaining East and West projects need to be blended for next meeting. There was a comment on the Long Term CIP (Capital Improvement Program) information shown on the graph regarding Phase two, which was not included. Hey’s current agreement only covers the phase one study area. There was discussion that the Commission does not want to hold another workshop with the community until Phase two is addressed. In addition, modeling of the North and South areas could also be requested at the same time that the East and West plan is presented. The Chair stated that while the overall analysis is not complete, he wants to return to the Board of Trustees and begin discussing the financing of the overall plan in general terms. Is it a utility tax that pays the debt service for a bond? Regarding cost versus time, Hey stated that they can provide a one page memo outlining the early out projects in terms of costs and timing. Rich asked if the proposed projects will solve basement flooding and Hey stated that the $45M project proposal outlined at the last meeting would have, but because of the costs the Commission asked Hey to return with a more realistic plan that utilizes overhead sewer cost share programs. This plan substantially reduces the amount of water that causes I/I that enters the system and adds to flooding. The proposed program also addresses basement backups and overland flooding issues throughout. The overall proposal should reduce street and yard flooding. Hey anticipates one more meeting and is interested in any feedback from the Commission on the draft plan. Fred Kudert stated that he sees value in the study even if for a majority of residents the overhead sewer cost share program is the most cost effective answer because we did our due diligence and the other parts of the study will help with the overland flooding issues which have been identified. He also asked Hey about the Phase two issue. “Can you take your phase one work and make some kind of ball park estimate of what might be needed for these other areas that have not been looked at in phase two, and develop a cost range of x to y dollars? So then in essence, with one meeting with the board you can show the details of the engineering in phase one and use them to provide an educated cost “guesstimate” on phase two so then for the Village of Niles there is a whole project cost sitting there in some way at the main presentation. It would be comprised of the A phase one detail cost that you have, plus the engineering guesstimate for what the extra costs might be for phase two. In this way the board sees what the whole picture is rather than waiting for all of phase two engineering to be done.” Hey said it could be tricky because an estimate may not provide a real value for any of the phase two projects and whether or not they should be prioritized ahead of anything in phase one. This estimate will at least provide a relatively close long term cost.  c. The Commission reviewed incident maps to determine what the phase two areas would be considered. Hey recommended estimating the cost for the remainder of the Village system with certain areas broken out for separate consideration. Major private sewer systems like Golf Mill will not be studied. 5. Ongoing Projects and Open Discussion: a. 9401 Western Avenue- Mosses Nazzal said that the owner was going to build a new garage and an addition to his house. Mosses stated that he asked to resident to put flood control in to reduce flooding. b. Glenview and Glendale Area – Scott not at meeting to provide update. c. 6730 Forest View Lane – Mosses Nazzal stated that Mr. Koos complained that ever since a garage to the east of his property was constructed, he has had stormwater problems. It has been stated that the two residents tend to complain about the other. There was discussion about how Mr. Koos was told to remove a berm he placed illegally. Nazzal informed Mr. Koos what to do, but it could have been constructed more effectively. It was stated that staff time being spent on this issue is being wasted until such time the Stormwater Commission develops a final master plan. If this becomes an isolated issue, it may need to be addressed through the rain garden program or possibly the flood proofing program discussed earlier in the meeting. It is unfortunate that his property is the lowest point, but a rear yard drain done by a professional would make a difference because the storm sewer in this area could handle the water. 6. Next Scheduled Meeting: TBD.