Stormwater Commission

STORMWATER COMMISSION MEETING SUMMARY Wednesday, August 31, 2011 The following persons were present: Chairman Joe Lo Verde, Mayor Robert Callero, Steven Vinezeano, Andrew Vitale, Mousa Nazzal, Richard Wlodarski, Scott Jochim, Fred Kudert, Chuck Ostman, Tom Polcyn and Jeff Wickenkamp/Patrick Lach of Hey and Associates. Also in attendance were Trustee Andrew Przybylo, resident Tom O’Malley, and three other unnamed residents from Bruce/Knight Ct. area of Niles. 1. Approve Meeting Summary of Wednesday, June 30, 2011: Vinezeano provided the summary to members prior to the meeting. The summary was approved to be posted on the Stormwater Commission web page. 2. Old Business: a. Prairie Farmer’s Creek MWRD Project by Hey. Hey and Associates, Jeff Wickenkamp, updated the Commission about the Prairie Farmers Creek Project being managed by the Metropolitan Water Reclamation District (MWRD). This program involves conveyance and storage modifications of overland water flow paths involving two creeks in the Des Plaines watershed, the Prairie Creek located North of Dempster between Potter and Greenwood and the Farmers Creek located West of Potter in the same area. These creeks co-join in Park Ridge ultimately connecting with the Des Plaines River. The plan proposes to modify six flow path areas, “FRCR” sections 1, 4, 7, 8 and 9 to improve water flow by actions such as reducing or removing various obstructions in the flow path and also lowering the water level in the Lutheran General Hospital retention pond. This region, while it is not directly connected to or bordering on Niles, is close enough whereby Niles may benefit to some degree from the proposed flow improvements as sub watersheds DP500, 550 and 600 from Niles drain into the Prairie Creek area. This program is not active at this time. Hey and Associates estimated that construction start could take up to five years. Trustee Przybylo asked about the relationship of the funding from County and whether or not there is a contact in County that can be informed that the project should be of high priority. Hey stated that the project is mainly in the hands of MWRD. A secondary relationship between Niles stormwater flow and this region was also discussed. This involves the Milwaukee and Maryland section which connects to the Prairie Creek area via sewer connections through the Shopping Plaza on the North side of Golf Road and under Milwaukee Ave. to the section just West of Greenwood, in the area where the Mil Green  business is located. An undetermined sewer connection is involved. Jochim stated that there were several attempts made by Niles Public Services to trace the connection, for analysis information regarding the flooding issues in the Maryland area, but they have not been successful. Vinezeano stated that he was going to investigate the matter and Hey followed up by stating that it was necessary information for the north study. 3. New Business: a. Modeling and Diagnosis by Hey. Hey and Associates, Jeff Wickenkamp presented an update on the status of the engineering analysis, with details, for the West side of Niles, focusing on the problem areas in the Northwest section defined by the area West of Milwaukee Ave. in the proximity of Greenwood and Dempster, and the Western boundary of Niles with Park Ridge. Several residents from the Bruce/ Knight Ct. area also participated in the discussion of this section. The discussion began with opening comments from Jeff Wickenkamp noting that significant physical constraints are present in this region, limiting the options to mitigate the localized flooding experienced in this area. They are as follows: 1) Section elevation. The west region is high at its eastern edge. This edge is defined by the ridge in Maryhill Cemetery which divides Niles between the Chicago River and Des Plaines River watersheds. The West region of Niles is in the Des Plaines River watershed. Subsequently this area’s natural overland flow path is east to West, towards the problem areas near and across from Greenwood Avenue. 2) Sewer Depth. The sewers in this area are shallow also because of its location at the eastern and starting edge of the Des Plaines River watershed. This condition significantly restricts the use of underground water storage approaches. It is also important to note that the west region is very limited in open land, generally requiring land acquisition in some form to implement above ground storage. All of the proposals that will be described below include above ground storage, with land acquisition, as a key part of their approach to flood water mitigation. Some significant uncertainties were raised later on in the meeting regarding several of the land acquisition components. These concerns are described in greater detail at the end of the summary. Hey and Associates presented details concerning two proposals for flood relief in this area. Both concepts involve the use of above ground detention areas (essentially a dry pond used to accumulate storm water) as the primary solution. Champaign Illinois was cited as a reference of a municipality that has successfully implemented a detention pond system within city boundaries to address storm water flooding. The two initial proposals differ in the amount of storage and the degree of flooding relief provided, and subsequently also in cost. Option 1 is a full scale approach with 60 acre feet of storage capacity. Option 2 is a smaller program. Option 3 was identified through the course of the discussion of the two initial proposals. This option involves designing for the maximum storage condition of approximately 60 acre feet of detention capacity, but implementing the project in two phases. The initial step would provide flood relief equivalent to the small scale system described in option 2, approximately 22 acre feet of storage. The second phase, which would be implemented at a later date, adds the additional storage capacity needed to reach the overall target of approximately 60 acre feet in capacity. Of note, the west side area is approximately 270 acres in its overall size. Based on the new stormwater regulations, an area of this size would require approximately 60 acre feet of storage capacity in new construction. The close fit between this general sizing requirement, which is based on the work of other agencies, and the results of the Hey’s study supports the accuracy of their detailed technical analysis. The three options are described as follows: Option 1: This is a combination of DPA1 and DPA3 providing 60 acre feet of detention capacity via a large detention pond created by transforming Greenwood Park into a detention area approximately 20 ft. in depth and with a pumping station. This essentially eliminates this area as usable park. In addition nine residences need to be acquired and removed as part of the construction and approximately 18,000 ft. of new sewers will be required to connect the problem areas; Bruce/Lincoln/Knight, North Terrace/Greenwood, Normal and Madison to the detention pond. The cost is estimated at approximately $20 million. Option 2: This combines DPA2 and DPA3 providing approximately 22 acre feet of detention capacity divided between two areas. 18 acre feet can be obtained by using open space, if attainable, at Our Lady of Ransom Church (OLR) and 4 acre feet would be added through converting some of the area at Greenwood Park. There is no need to acquire any residences in this approach. The approximate cost for this option is estimated at $7 million. Option 3: This involves implementing Option 2 based on an Engineering design that would accommodate the addition of 40 acre feet of detention capacity at an additional site, possibly Greenwood Park, at a later date. While not discussed, the expected cost for phase I of this two phase program would be approximately $7 million, since it generally duplicates option 2. Costs for Phase II, the addition of 40 acre feet of additional storage capacity at a later date needs to be estimated. Also, in Options 1, 2 and 3 a small section of underground storage accomplished by installing appropriately sized sewers and a pumping system would be installed in the Carol/Crain/Grace area. The degree of flood relief that each option is estimated to provide is described in the following. The improvements are based on a comparison of the degree of individual flooding from surface waters that may be expected, based on the modeling, against a 10 year rain event (2.5” or more) and a 100 year event (6” or more). Base Condition: Number of homes currently impacted with conditions as is:  10 year event – 39 homes  100 year event – 118 homes (includes the 39 expected in a 10 year event) Improvement from Option 1:  10 year event – no residential flooding expected  100 year event – approximately 12 homes may experience residential flooding. Improvement from Option 2:  10 year event – approximately 4 homes may experience residential flooding.  100 year event – approximately 68 homes may experience residential flooding. Improvement from Option 3:  Phase 1 - Same as Option 2  Phase 2 - Same as Option 1 Tom O’Malley, a Bruce/Knight area resident asked to address the committee on behalf of himself and other residents in his area that experience flooding. Tom identified that he does not believe that his residence experiences direct overland flooding, but floods from overflow water that is ejected from the sewers in his area, generating street flooding which then becomes surface flooding at his residence and at several other homes in his area. Tom described for the committee his understanding of the sewers in this area, that there are two (2) 60” diameter sewers which co- join and then connect to an 18” diameter sewer eventually connecting into the Park Ridge system. He then raised the question concerning the 18” connection and his opinion that the street flooding occurs because the 18” section greatly reduces the flow from the two (2) main 60” sections. To review and discuss Tom O’Malley’s concerns, Jeff Wickenkamp displayed the Niles Sewer Atlas section which describes the actual sewer system in the area in question. The drawing identifies two separate 30” diameter sewer segments in Knight and a similar set of twin units in Bruce. These two sets of twin 30” sections co-join approximately at the corner of Knight and Bruce, to one 18” diameter section. The drawing also identified that the two twin 30” sections only connect to the Park Ridge system via the 18” connection identified above. These main sections do not connect with any other sewer. They are not a through conveyance segment. The 18” section is a restriction, by design, for the purpose of regulating the discharge rate from the two sets of twin 30” storage sewers. The drawings also show that the twin 30” sections are dedicated to this area of Bruce and Knight in order to provide underground storage of surface water which naturally drains from the West Side region, as initially described in this summary. Normal and Lincoln are the primary overland flow paths to the Bruce/Knight area. The possibility that back flow from the Park Ridge system may be one of several causes for generating the overflow conditions described by Tom O’Malley was discussed. It was also noted that Greenwood sewers discharge into Sunset through a restrictor and that surcharges in this section could possibly vent through manholes onto Sunset and Normal, leading to the Bruce/Knight area and adding to the accumulation of storm water in this area. Subsequently, there was a brief discussion initiated by Ostman of possible short term options to reduce Bruce/Knight flooding. These included the installation of a check valve in the 18” section that connects with Park Ridge to function as a back flow preventer, if this is proven to relate to the flooding conditions described by Tom O’Malley. Closing the manholes on Sunset and Normal to redirect the surcharge mentioned above may lead to problems elsewhere and this does not appear to be viable. In addition the option to re-instate storage capacity in the OLR field along Lincoln Ave. and or lowering Normal Ave. for the storage of overland flow were also mentioned as other possibilities. All of the above are outside of the scope of the West Side program options at this time and would need to be reviewed in further detail as a separate activity. No additional action was planned at this meeting. Mayor Callero also identified that the twin sets of sewers in discussion where installed in the Bruce/Knight area in approximately in 1995 as storage reservoirs, and that they worked well with no local flooding that he recalls of, for over 10 years. This prompted a brief discussion of what has changed leading to a brief review of weather records for the Niles area. Jeff Wickenkamp displayed historical rain fall data from Cook County Gauge No. 3, located at Oakton and Des Plaines Rd. It showed the two large events of 2008 (6.5”) and the recent July event (5.8”) as the two outliers from what was otherwise a generally consistent pattern of one to  two 1.5” rain events each year. It was also noted that Niles rain gauges at Ballard and Cumberland and Touhy and Milwaukee often show significant differences in rainfall amounts for a given event. In general, no significant explanation for the increase in flooding frequency in the Bruce/Knight area was evident in the weather data that was reviewed. 4. Ongoing Projects and Open Discussion: a. Illinois Green Infrastructure Grant (IGIG). Steve Vinezeano reported that $202,224 was awarded to Niles towards implementation of the Neva Avenue Bioinfiltration Facility project. This was the first year for this grant from the Illinois Environmental Protection Agency (IEPA). There are several goals to the project. 1. Reduce pollution; 2. Beautify the area; and 3. Eliminate the potential impact from snow melt. b. Utility Repair Program. Scott Jochim discussed the Nicor Gas Sewer Line Repair Plan. This is an insurance program that is available to individual homeowners. It appears that this program could be of value to individual homeowners in the event that they experience problems with the lateral sewer connection from their home to the street, which is the homeowner’s cost responsibility in Niles. Specific information from Nicor Gas was included in the meeting agenda. c. Public Services and Policy of Pumping Private Basements. Scott also briefly reviewed a policy regarding pumping flooded basements as a Village function. It is Niles policy to not enter or pump individual flooded basements for safety reasons regarding possible electrocution from live power in a flooded basement. It was recommended that this policy remain as is, which is similar to Fire Department regulations. d. Greenwood Restrictor. Tom Polcyn reported on the question concerning the size of the restrictor in the Greenwood sewer. It is now at 12”. If manhole surcharges are occurring, a 10” restrictor, which was previously in place, could be re-installed. Vinezeano requested that the 10” be reinstalled. e. Data Collection for Utilities. Ostman discussed the purchase of a hand held data collection device which will allow for field updates of the Niles sewer system records and provide field data access. It was recommended that the purchase of this unit at a cost of approximately $25,000 is pursued. Andrew Vitale stated that the GIS Steering Committee will be discussing the device. 5. Next Scheduled Meeting:  September 7, 2011 - The purpose of the September 7 meeting will be to review the complete Hey and Associates Phase I analysis summary and recommendations in preparation for the September 27 Village Board  Meeting. A special request will be made to the Village Board members to attend this meeting.  September 27, 2011 - The purpose of the September 27 meeting is to formally present the results and recommendations of Phase I of the storm water analysis to the Board. This presentation will include the analysis results and recommendations for the East and West side areas. Based on what Hey has learned about Niles conditions from their analysis of the West and East sides, a professional estimate of possible costs to address localized flooding issues in the North and South areas will also be included in order to provide directional information concerning the possible overall program cost. Several steps between the September 7 and 27 meetings were also identified. The information from the September 7 meeting will be forwarded to Finance for cost and funding analysis. A formal Finance committee meeting will be scheduled for September 21 to prepare funding information for the Village Board presentation. Key property owners related to implementing the West Side detention system options will also be contacted prior to the September 27 meeting in order to review feasibility of the land acquisition required in these proposals. They are the Chicago Archdiocese regarding land at OLR and the Niles Park District concerning the Greenwood Park Site. Mayor Callero noted that acquiring or accessing land at OLR may be very difficult because of the Archdiocese historic reluctance to sell properties. Because of this and Trustee LoVerde’s concern on the loss of usable park area, Trustee LoVerde suggested a possible backup option to consider, the acquisition of individual homes south of Greenwood Park in an area that has experienced a high rate of flooding. The meeting was adjourned at noon.