City Council Planning Sessions

1. City Council Planning Agenda Documents: 2016-09-26 CITY COUNCIL PLANNING AGENDA.PDF 2. City Council Planning Minutes Documents: 2016-09-26 CITY COUNCIL PLANNING MINUTES.PDF 3. City Council Planning Draft Minutes 10-24-2016 Ps02 Documents: 2016-09-26 CITY COUNCIL PLANNING DRAFT MINUTES 10-24-2016 PS02.PDF 4. City Council Planning Draft 2016-08-22 Minutes Ps02 Documents: 2016-09-26 CITY COUNCIL PLANNING DRAFT 2016-08-22 MINUTES PS02.PDF 5. City Council Planning Briarcliffe Flood Study Update Ps04 Documents: 2016-09-26 CITY COUNCIL PLANNING BRIARCLIFFE FLOOD STUDY UPDATE PS04.PDF  WHEATON CITY COUNCIL PLANNING SESSION WHEATON CITY HALL – COUNCIL CHAMBERS 303 W. WESLEY STREET, WHEATON, ILLINOIS MONDAY, SEPTEMBER 26, 2016 - 7:00 P.M. AGENDA I. Call to Order II. Approval of Minutes – August 22, 2016 III. Public Comment IV. Briarcliffe Flood Study Update V. City Council/Staff Comments VI. Adjournment During the Public Comment portion of the agenda, the presiding officer shall recognize any person requesting to be heard on any of the planning session agenda items only. Persons speaking during Public Comment shall not speak longer than three (3) minutes and shall be permitted to speak only once. Visitors must remain quiet and not engage in behavior that interferes with the Planning Session. The presiding officer may, or upon a majority vote of the council, request any visitor who violates any provision of this paragraph to leave the council chambers, and such visitor shall thereupon leave. Any person providing public comment shall address the presiding officer only and shall not proceed with remarks until recognized. When recognized, the person shall state his or her name and address. Cross floor discussions are prohibited. If a member of the City Council has questions of any person who has provided public comment, that person may address the specific question.  MEMORANDUM TO: Record FROM: Susan Bishel, Public Relations Coordinator SUBJECT: Sept. 26, 2016 City Council Planning Session Minutes DATE: Sept. 27, 2016 CC: Mayor and City Council, City Manager, City Clerk, Department Heads The Planning Session took place in the Council Chambers, Wheaton City Hall, 303 W. Wesley St., Wheaton, Illinois. Those attending the Planning Session included: Councilwoman Fitch, Councilman Prendiville, Councilman Rutledge, Councilman Saline, Councilman Scalzo and Mayor Pro Tem Suess. Mayor Gresk was absent. Also in attendance were City Manager Dzugan, Assistant City Manager Duguay, Director of Engineering Redman, Senior Project Engineer Tebrugge, Project Engineer Dunn, and Public Relations Coordinator Bishel. The session began at 7:00 p.m. and concluded at 8:16 p.m. The following items were discussed: I. Call to Order The Wheaton City Council Planning Session was called to order at 7:00 p.m. by Mayor Pro Tem Suess. II. Approval of Aug. 22, 2016 Planning Session Minutes The Council approved the Aug. 22, 2016 Planning Session Minutes. III. Briarcliffe Flood Study Update Director of Engineering Redman provided an update to City staff’s previous presentation on what can be done in regard to flooding in the Briarcliffe area. The City contracted Christopher B. Burke Engineering to further analyze the downstream effects that suggested work would create. Erik Gil, a project engineer with Christopher B. Burke Engineering, reviewed the watershed area, approximately 2/3 of which is in Wheaton and 1/3 of which is in Glen Ellyn. The watersheds are served by a series of large lakes that are interconnected with large storm sewers. Mr. Gil reviewed the FEMA map showing which areas are considered floodplain, and he reviewed significant storms that occurred in 2008, 2010 and 2013. In response to Council questions, Senior Project Engineer Tebrugge said one of the lakes barely overtopped in 2008 and needed sandbags to prevent flooding, but it was much less than the event in 2013. Mr. Gil reviewed the circumstances that contributed to significant flooding in 2013, which included the concentration of rain in a short time, and saturated ground conditions from previous rain. This second study analyzed a larger area, including Rice Lake, which is where stormwater in the proposed plan would travel. Through this study, Mr. Gil stated they were able to see that Rice Lake overtopped onto Leask Lane during the significant storm in April 2013, and water traveled in a different direction than usual in some areas because of overflow conditions. Based on the models in their analysis, Mr. Gil stated a 100-year critical duration event would not damage any structures but would collect water on some grassy areas. DuPage County requires that any project that would raise water levels more than 0.5 feet as needing to be either mitigated or approved by the downstream property owners. In response to Council questions, Mr. Gil stated that simply raising the land at the low point of Rice Lake would not necessarily work in preventing overtopping. In response to Council questions, Mr. Gil stated in a 100-year critical duration event, the flooding would not affect any residential structures in the proximity of Rice Lake. Director of Engineering Redman stated some of the areas are stormwater detention areas, and other parts are Wheaton Park District-owned land. In response to Council questions, Mr. Gil stated the ability to increase the capacity of stormwater areas would be limited. Senior Project Engineer Tebrugge showed photos of the emergency spillway near Rice Lake and where water would go during a 50-year or 100-year storm event. Based on Christopher B. Burke Engineering’s modeling, the flooding would not reach high enough to affect any structures. Senior Project Engineer Tebrugge stated the City did a FEMA benefit cost analysis of this project, and City staff visited homes near Lake 4 to obtain additional information. Based on FEMA’s benefit cost analysis, the City could qualify to apply for a competitive grant program, where 75% of the project’s costs would be matched with federal funding, to complete Alternative 4 or a buyout program. However, the City would still need permission from property owners downstream for the City to complete Alternative 4. City staff suggested presenting information about Alternative 4 to the DuPage Forest Preserve District to see if this project would be acceptable. In response to Council questions, City Manager Dzugan stated the values for the homes that could be considered for a potential buyout were based upon their most recent assessed value. In response to Council questions, Senior Project Engineer Tebrugge stated that the purpose of buyouts would be to take out homes that would be damaged in significant storm events, and it would not have a measureable decrease on the water that travels downstream. IV. Public Comment Randy Rasmussen, 1879 Briarcliffe, expressed concern that previous estimates significantly undervalued the worth of his home, and he wondered if this has been corrected. Director of Engineering Redman stated these are initial value estimates and would not be the values used if the City were to consider buyouts. He stated the City is not seriously considering 9/26/16 Planning Session 2 buyouts at this point, and all buyouts would be voluntary for qualifying property owners. If the City did want to proceed with buyouts, FEMA would require appraisals for properties. Gary Burge, 1733 Brentwood Lane, asked if building up the perimeter of Rice Lake would prevent it from overtopping. Senior Project Engineer Tebrugge stated it would provide more storage, but it would not have much of an effect on a 100-year or 50-year storm event. Crystal Nesson, 1845 Brentwood Lane, expressed concern with the frequency of flooding on her property. She asked what could be done for residents whose properties experience flooding in less severe storms than 2013. Senior Project Engineer Tebrugge stated that typically the 100- year event is used as a standard because work that would prevent flooding at a 100-year event level would also protect homes in the lesser storms. Tim Whelan, 518 Robinwood Lane, stated he lives near Leask Lane. He stated as a DuPage Forest Preserve District Commissioner, he doesn’t think there has been enough exploration into what the Forest Preserve District can do with Rice Lake, and he would like to explore this with the City to address the stormwater issue. City Manager Dzugan stated the next step would be to meet with representatives from the Forest Preserve District and see if they can work toward a solution. City staff thinks Alternative 4 appears to be the most cost-effective solution and would be the City’s best shot at receiving FEMA funding. He stated this project has significant costs and would be difficult to fund without assistance. City Manager Dzugan stated there are a number of other flood-prone areas in Wheaton that the City is also analyzing. In response to Council questions, Senior Project Engineer Tebrugge stated the current level of protection in the Briarcliffe area is as low as the 10-year protection level in the lowest spots. FEMA’s standard is protection to the 100-year level. V. City Council/Staff Comments There were no City Council/Staff comments. VI. Adjournment The meeting was adjourned at 8:16 p.m. 9/26/16 Planning Session 3  MEMORANDUM TO: Record FROM: Susan Bishel, Public Relations Coordinator SUBJECT: Sept. 26, 2016 City Council Planning Session Minutes DATE: Sept. 27, 2016 CC: Mayor and City Council, City Manager, City Clerk, Department Heads The Planning Session took place in the Council Chambers, Wheaton City HaIl, 303 W. Wesley St., Wheaton, Illinois. Those attending the Planning Session included: Councilwoman Fitch, Councilman Prendiville, Councilman Rutledge, Councilman Saline, Councilman Scalzo and Mayor Pro Tern Suess. Mayor Gresk was absent. Also in attendance were City Manager Dzugan, Assistant City Manager Duguay, Director of Engineering Redman, Senior Project Engineer Tebrugge, Project Engineer Dunn, and Public Relations Coordinator Bishel. The session began at 7:00 p.m. and concluded at 8:16 p.m. The following items were discussed: I Call to Order The Wheaton City Council Planning Session was called to rr at 7:00 p.m. by Mayor Pro Tern Suess. II. Approval of Aug. 22, 2016 Planning Session Minutes The Council approved the Aug. 22, 2016 Planning Session Minutes Ill. Briarcliffe Flood Study Update Director of Engineering Redman provided an update to City staff’s previous presentation on what can be done in regard to flooding in the Briarcliffe area The City contracted Christopher B Burke Engineering rther analyze the downstream effects that suggested work would create. Erik Gil, a project engineer with Christopher B. Burke Engineering, reviewed the watershed area, approximately 2/3 of which is in Wheaton and 1/3 of which is in Glen Ellyn. The watersheds are served by a series of large lakes that are interconnected with large storm sewers. Mr. Gil reviewed the FEMA map showing which areas are considered floodplain, and he reviewed significant storms that occurred in 2008, 2010 and 2013. In response to Council questions, Senior Project Engineer Tebrugge said one of the lakes barely overtopped in 2008 and needed sandbags to prevent flooding, but it was much less than the event in 2013. Mr. Gil reviewed the circumstances that contributed to significant flooding in 2013, which included the concentration of rain in a short time, and saturated ground conditions from previous rain. This second study analyzed a larger area, including Rice Lake, which is where stormwater in the proposed plan would travel. Through this study, Mr. Gil stated they were able to see that Rice Lake overtopped onto Leask Lane during the significant storm in April 2013, and water traveled in a different direction than usual in some areas because of overflow conditions. buyouts at this point, and all buyouts would be voluntary for qualifying property owners. If the City did want to proceed with buyouts, FEMA would require appraisals for properties. Gary Burge, 1733 Brentwood Lane, asked if building up the perimeter of Rice Lake would prevent it from overtopping. Senior Project Engineer Tebrugge stated it would provide more storage, but it would not have much of an effect on a 100-year or 50-year storm event. Crystal Nesson, 1845 Brentwood Lane, expressed concern with the frequency of flooding on her property. She asked what could be done for residents whose properties experience flooding in less severe storms than 2013. Senior Project Engineer Tebrugge stated that typically the 100- year event is used as a standard because work that would prevent flooding at a 100-year event level would also protect homes in the lesser storms. Tim Whelan, 518 Robinwood Lane, stated he lives near Leask Lane. He stated as a DuPage Forest Preserve District Commissioner, he doesn’t think there has been enough exploration into what the Forest Preserve District can do with Rice Lake, and he would like to explore this with the City to address the stormwater issue. City Manager Dzugan stated the next step would be to meet with representatives from the Forest Preserve District and see if they can work toward a solution. City staff thinks Alternative 4 appears to be the most cost-effective solution and would be the City’s best shot at receiving FEMA funding. He stated this project has significant costs and would be difficult to fund without assistance. City Manager Dzugan stated there are a number of other flood-prone areas in Wheaton that the City is also analyzing. In response to Council questions, Senior Project Engineer Tebrugge stated the current level of protection in the Briarcliffe area is as low as the 10-year protection level in the lowest spots FEMA s standard is protection to the 100-year level V City CouncillStaff Co ts There were noCy Council! commeq. VI Adjournment The meeting was adjourned at 8 16 p m / 9/26/16 Planning Session 3 Based on the models in their analysis, Mr. Gil stated a 100-year critical duration event would not damage any structures but would collect water on some grassy areas. DuPage County requires that any project that would raise water levels more than 0.5 feet as needing to be either mitigated or approved by the downstream property owners. In response to Council questions, Mr. Gil stated that simply raising the land at the low point of Rice Lake would not necessarily work in preventing overtopping. In response to Council questions, Mr. Gil stated in a 100-year critical duration event, the flooding would not affect any residential structures in the proximity of Rice Lake. Director of Engineering Redman stated some of the areas are stormwater detention areas, and other parts are Wheaton Park District-owned land. In response to Council questions, Mr. Gil stated the ability to increase the capacity of stormwater areas would be limited. Senior Project Engineer Tebrugge showed photos of the emergency spillway near Rice Lake and where water would go during a 50-year or 100-year storm event Based on Christopher B Burke Engineering’s modeling, the fi •would not reachhigh enough to affect any structures. Senior Project Engineer Tebrugge state City did a FEMA benefit cost analysis of this project and City staff visited homes near Lake 4 to obtain additional information Based on FEMA s benefit cost analysis the City could qualify to apply for a competitive grant program where 75% of the project s costs would be matched with federal funding to complete Alternative 4 or a buyout program However the City would still need permission from property owners downstream for the City to complete Alternative 4 City staff suggested presenting information about Alternative 4 to the DuPage Forest Ditrict to see if this project would be acceptable. In response to Council questions, City Manager Dzugan stated the values for the homes that could be considered for a potential buyout were based upon their most recent assessed value. In response to Council questi Senior Project Engineer Tebrugge stated that the purpose of , buyouts would be to take ouf omes that would be damaged in significant storm events, and it would not have a measureable decrease on the water that travels downstream. IV. Public Comment Randy Rasmussen, 1879 Briarcliffe, expressed concern that previous estimates significantly undervalued the worth of his home, and he wondered if this has been corrected. Director of Engineering Redman stated these are initial value estimates and would not be the values used if the City were to consider buyouts. He stated the City is not seriously considering 9/26/16 Planning Session 2  MEMORANDUM TO: Record FROM: Susan Bishel, Public Relations Coordinator SUBJECT: Aug. 22, 2016 City Council Planning Session Minutes DATE: Aug. 23, 2016 CC: Mayor and City Council, City Manager, City Clerk, Department Heads The Planning Session took place in the Council Chambers, Wheaton City Hall, 303 W. Wesley St., Wheaton, Illinois. Those attending the Planning Session included: Mayor Gresk, Councilwoman Fitch, Councilman Prendiville, Councilman Rutledge, Councilman Saline, Councilman Scalzo and Councilman Suess. Also in attendance were City Manager Dzugan, Assistant City Manager Duguay, Director of Planning & Economic Development Kozik, Director of Finance Lehnhardt, Director of Engineering Redman, Public Information Officer Thrower, and Public Relations Coordinator Bishel. The session began at 7:00 p.m. and concluded at 8:30 p.m. The following items were discussed: I. Call to Order The Wheaton City Council Planning Session was called to order at 7:00 p.m. by Mayor Gresk. City Manager Dzugan introduced Arm Thrower, the new Public Information Officer in the City’s Communications Department. II. Approval of Aug. 8, 2016 Planning Session Minutes % The Council approved the Aug. 8, 2016 Planning Session Minutes. Ill. Public Comment There were no pqments. IV. Downtown Strategic Plan Infrastructure Scope and Funding City Manager Dzugan summarized the key milestones in developing a Downtown Strategic Plan, which began in 2012. In June, Design Workshop presented the Council with plan implementation options broken down into “good,” “better” and “best” categories. City staff looked at ways to scale back elements of the project in order to make it more economically feasible. Director of Planning & Economic Development Kozik stated the difference between the good/better/best categories would be a greater quantity of the higher-end materials in the better and best categories, such as more permeable payers and holiday lighting. City Manager Dzugan reviewed a number of assumptions and acknowledgements that will guide this project. These include a project length of 4-5 years, using design concepts from the “good” category developed by Design Workshop, changing some of the street types from the original Strategic Plan, and not including the category of “other streets” from the original plan. City Manager Dzugan also outlined costs that are not included in the scope estimates, including traffic signals, some streetlights outside of the immediate project area, alley improvements, possible sidewalk repairs outside of the project area, and upgrades to Martin Plaza. City staff also developed assumptions for project phasing, including that the project would address failing or deteriorating infrastructure first and use a linear construction approach rather than block by block for improved efficiency and pedestrian access. In response to Council questions, Director of Engineering Redman stated projects could take up to the entire construction season. City Manager Dzugan reviewed three scopes of work and the associated costs for each. Scope 1 would be a 4-year project costing an estimated $23.8 million, including $1 million for a park concept south of the railroad tracks and $1 .5 million invested in French Market improvements. Scope 2 would be a 5-year construction period with estimated costs of $31 million, including $1 .5 million for the park construction and $2 million for the French Market. This scope also added 5 street segments. Scope 3 is estimated to cost $36.6 million, with $2 million for the park construction and $3.5 million for the French Market. This scope would add 3 sections and would take 5 years to complete. City staff also developed assumptions that shape the recommended funding options. The figures in these proposals assumed a 1.5% annual increase for TIF 2 and no significant tax assessment appeals, that expenses will be TI F-eligible within TIF Districts 2 and 3, and TIF 2 expires in 2022-23 with no extensions. Staff estimated that a 0.25% sales tax increase would generate approximately $900,000 of new revenue per year, and a new 0.25% Food & Beverage Tax is estimated to generate $200,000 annually. City Manager Dzugan reviewed the City’s Capital Projects Fund Reserve, current debt obligation, and stated the proposed scopes of work assume the City would not rely on property tax for funding. The City will also need to consider other capital needs for future projects including th Road Program street reconstruction stormwater management and other infrastru% eds City Manager Dzugan review two funding options for Scope 1, one of which use $17.6 million in TIF funding, issue a $5 milli 10-year bond, implement a 0.25% local sales tax, borrow about $2 million from the General Fund to meet cash needs, and fund the remaining $1.2 million from the Capital Projects Fund. The other option would also use $17.6 million in TIF funding and borrow the same amount from the General Fund, and fund the remaining $6.2 million from the Capital Projects Fund. The two options for Funding Scope 2 include $20.6 million of funding from TIF 2, borrowing $2 million from the General Fund to meet cash needs, issuing a $10 million 15-year bond, implementing a 0.25% local sales tax, and using $30,000 from the Capital Projects Fund. The second option would fund the entire $10.3 million in non-TIF related expenses through the Capital Projects Fund, rather than issuing a bond and a 0.25% sales tax. The funding option presented for Scope 3 would use $21 million of TIF 2 revenue, issue one $10 million 15-year bond and one $5 million 10-year bond, and implement a $0.25 sales tax. 8/22/16 Planning Session 2 City Manager Dzugan recommended the City Council consider Scope 1, Funding Option A. In response to a Council question about why the City wouldn’t borrow the full $6.2 million of non TIE eligible funds in Scope 1, City Manager Dzugan stated the City would need to levy for the debt service. The next steps for this project would be to contract with a civil engineer to begin developing drawings and specifications for Phase 1, Front Street from West to Cross, continuing to work with Design Workshop and CCS to oversee the process, and establishing an oversight/review process with pre-determined checkpoints for design development and other stages. Some Council members expressed a desire to use the portions of Scope 2 and 3 that related to the French Market and improvements south of the railroad tracks. Other Council members disagreed and expressed concerns about investing in the French Market, which would not benefit the community year-round. In response to Council questions, Director of Planning & Economic Development Kozik stated he believes that Design Workshop did not create a plan for Martin Plaza because their project would shift the focus to the new park and festival street on Liberty Drive. The Council expressed a desire to include improvements to Martin Plaza in the Front Street portion of this project. In response to a Council question, Director of Planning & Economic Development Kozik stated the off-street spaces along Liberty Drive are part of a long-term lease agreement with RJN. The City has discussed with RJN moving these spaces to a City garage, and RJN expressed support for this project. Director of Planning & Economic Development Kozik stated the City oversells leases to the garage on thoth side of the railroad tracks by 25-30% of its capacity, yet there are still vacancies. City Manager Dzugan stated City staff would like to start on Front Street to give the city a better picture of the rest of the project and serve as a template for future work. By putting the French Market portion of the project last, it would give the City time to revisit the plan and modify them if needed. Starting with one part of the project would also allow the City to move forward with Front Street and Martin Plaza improvements yet hold off on increasing the local sales tax until the City determines if it is needed. Based on the City Council’s input City Manager Dzugan stated City staff will put together a Request for Qualifications and Request for Proposals for the Front Street project, which could potentially go out to bid for the next construction season. V. City Council/Staff Comments Councilman Prendiville thanked City staff for all of their work on the Downtown Strategic Plan. VI. Adjournment The meeting was adjourned at 8:30 p.m. 8/22/16 Planning Session 3 Memorandum Joseph E. Tebrugge Senior Project Engineer – Development / Stormwater To: Honorable Mayor and City Council Date: September 23, 2016 Re: Briarcliffe Flood Study Update Introduction The Briarcliffe Lakes System Flood Study was initiated in response to the April 13th, 2013 storm event which caused significant flood damages in the City of Wheaton Flood Prone Area “Brentwood Lane East of Briarcliffe Boulevard”. The Flood Study was completed in January 2015and presented to the City Council on May 11, 2015. The most cost effective solution provided in the alternative analysis was the installation of a large diameter storm sewer (Alternative 4) from the Flood Prone Area to Windsor Channel which would route floodwaters to Rice Lake which is owned by the DuPage County Forest Preserve District. A map depicting Alternative 4 is attached (Attachment 1) The City Council directed Staff to complete additional study to determine if the Alternative 4 project created downstream impacts which would preclude its construction. Mr. Erik Gil of Christopher B. Burke Engineering Ltd. will be providing a formal presentation at the planning session to provide a summary of the results of the Briarcliffe Downstream Impact Analysis. Briarcliffe Downstream Impact Analysis The Downstream Impact Analysis is attached (Attachment 2) which only analyzed the 100 year storm condition. In the 100 year storm condition it was shown that with the Alternative 4 project there is an impact to Rice Lake which increases the flooding in the Lake by 0.13 feet which is above the regulatory limit of 0.10 feet. When downstream impacts of 0.10 feet are present as per the DuPage County Stormwater Ordinance the affected property owners must approve of the impact with a formal sign off letter OR the project must be modified to mitigate the downstream impacts. In the 100 year storm analysis there were no additional impacts downstream of Rice Lake. After the Downstream Impact Analysis Report was completed additional analysis was done by modeling a fuller range of storms to determine if there were any additional downstream impacts from lesser events. This analysis and modeling discovered that there were no impacts of concern from the Alternative 4 project from storms ranging up to the 50 year storm. However in the 50 year storm not only were additional impacts discovered in Rice Lake of 0.35 feet, additional impacts downstream of Rice Lake were also discovered with a maximum change in flood heights of 1.11 feet. The Summary of the changes in the 50 year flood heights and the 50 year inundation map are attached (Attachment 3). FEMA Benefit Cost Analysis Update An important part of determining the feasibility of the Alternative 4 project is determining whether FEMA funding is a possible option. FEMA Hazard Grant Mitigation Program (HGMP) is a highly competitive program that provides a possible 75% of costs paid by Federal Grant. In order for a project to be eligible for the program it must show a Benefit Cost Ratio above one, which means that the benefits in damages removed exceeds the Cost of the Project. City Staff worked with resident property owners shown as impacted by the Briarcliffe Lakes System Flood Study to gather required information from 42 out of the 49 homes. Using data directly from the Flood Study and the data gathered from the interior home surveys the FEMA Benefit Cost Software initial analysis estimated that the damages over the next 100 years for this area are $80,767,785.00. Using the estimates provided in the Briarcliffe Lakes System Flood Study: The Benefit Cost Analysis (BCA) for the Alternative 4 project is 7.74. The BCA for Buyouts is 5.50. Using the current tax assessed values for Buyout the BCA is 5.19. Based on this information it appears that FEMA funding is possible for either a buyout project or for the Alternative 4 Project. It must be stressed however that FEMA funding is very competitive and may take years to obtain. The current FEMA Benefit Cost Analysis Map is attached. (Attachment 4) Where to go now? Based on the current Downstream Impact Analysis there are downstream impacts to Rice Lake located on DuPage County Forest Preserve property, downstream right of way owned by the City, and three parcels downstream of Rice Lake all which are current stormwater retention ponds. These parcels are under control of two downstream Homeowners Associations. No impacts have been shown to private property under singular private control. In order to move forward with the current Alternative 4 project one of the following conditions must be met: 1) The downstream impacts must be acknowledged and accepted by the impacted owners with a formal acceptance letter. 2) The project must be modified to show no downstream impacts. Options for this are: a. Lowering the design protection provided to the Flood Prone Area. b. Additional Engineering Analysis to determine if enough storage can be added to Rice Lake to eliminate the additional downstream impacts downstream of Rice Lake. This will increase the project cost of Alternative 4 and still require sign off from the Forest Preserve. Additional project costs would also lower the BCA decreasing chances of receiving Federal Funding. In order to continue with the Briarcliffe Project, given that Alternative 4 provides the best opportunity for Federal FEMA Funding and a higher BCA, Staff suggest further reviewing impacts of Alternative 4 with a presentation to the DuPage County Forest Preserve on impacts to determine if the impacts would be accepted by the Forest Preserve. ATTACHMENT 1  Lake 4 Pond 7 ninc Glen Ellyn Glen Ellyn Southern Embankment Proposed 4' (H) x 10' (W) RCBC Bypass Box Uninc Wheaton Proposed 5' (H) x 8 (W)' RCBC Bypass Box Uninc Wheaton Uninc Legend Municipal Boundary Wheaton Proposed Storm Sewer Uninc Berm Rehabilitation Proposed Basin 100-Year, 48-hour Inundation Area Not Studied in Detail BRIARCLIFFE LAKES SYSTEM FLOOD STUDY ALTERNATIVE 4 PROJECT ATTACHMENT 2 March 8, 2016 TO: Joseph Tebrugge, PE – City of Wheaton FROM: Jeana Gowin, PE, CFM Erik Gil, PE, CFM SUBJECT: Briarcliffe Lakes Flood Study – Downstream Impacts Alternative Analysis City of Wheaton, DuPage County, Illinois (CBBEL Project No. 13-0480) On behalf of the City of Wheaton (City), Christopher B. Burke Engineering, Ltd. (CBBEL) has updated the hydrologic and hydraulic analysis of the Briarcliffe Lakes stormwater management system. CBBEL previously performed an XP-SWMM hydrologic and hydraulic analysis of the City’s existing conveyance system from Roosevelt Road to the upstream face of Butterfield Road, including the XP-SWMM modeling that was prepared by V3 Companies for the Williston Basin watershed that was appended to account for the area upstream of Roosevelt Road. As part of this update, the XP-SWMM hydraulic analysis was extended from the upstream face of Butterfield Road to approximately 150 feet downstream of Arboretum Circle. Approximately 900 acres of area that is tributary to the expanded study area was added to the hydraulic model. The total study area is shown on Exhibit 1. Upstream of Butterfield Road, the main trunk storm sewer line and eight online storage areas were previously modeled. In this downstream analysis, three additional storage areas were added for the areas west of Windsor Channel to the downstream limit of the analysis; and twenty-two cross-sections, the Rice Lake berm overtop (elevation 726.92 ft NAVD 88), and three roadway crossings – including Butterfield Road – were surveyed and included in the hydraulic model. The purpose of this analysis was to confirm the inundation area downstream of Butterfield Road, including Rice Lake, for the April 17-18, 2013 storm event, and to evaluate possible downstream impacts that Alternative 4 may incur. Based on field observation, there was a significant amount of debris blocking the outlet weir of Rice Lake, thus artificially raising the normal water level (NWL). The measured debris line is approximately 1 feet above the existing outlet weir, thus reducing the available storage volume within Rice Lake by 60 acre- feet. CBBEL simulated the debris-blocked outlet scenario and used this for both the baseline and proposed modeling. Exhibit 2 shows the simulated April 2013 storm event inundation areas. Table 1 provides a summary of various locations (Exhibit 3) in the additional study area, the April 2013 storm event simulated elevations, and the depth of water at these locations. 1  Table 1: Summary of Water Surface Elevations Downstream of Butterfield Road for the April 17-18, 2013 Storm Event Simulated Location ID on April 17-18, 2013 Depth of Water Location Exhibit 3 Elevation (ft) (NAVD88) Rice Lake 1 727.4 0.5 (Overtop Elevation 726.9 ft NAVD 88) Rice Lake Outlet Structure – 2 719.9 1.8 Downstream Face 3 Rice Lake Overflow Weir 721.4 0.9 Leask Lane East Ditch – 4 719.7 1.0 Upstream of Private Drive 5 Upstream Face of Robinwood Lane 717.9 4.3 Leask Lane East Ditch – 6 716.6 1.6 Downstream of Robinwood Court 7 Upstream Face of Arboretum Circle 716.7 4.6 Based on the above analyses, it appears that Rice Lake overtopped in the April 2013 storm event by approximately 6 inches. This is mainly due to the blockage at the outlet grate. Additionally, our analysis indicates that Leask Lane also overtopped in two locations: 1) at the intersection of Leask Lane and Robinwood Lane, and 2) upstream of the intersection of Leask Lane and Arboretum Circle. Moreover, both Robinwood Lane and Arboretum Circle overtopped. The depth of ponding at these locations varies between 1 inch and 3 inches on Leask Lane, 9 inches on Robinwood Lane, and 5 inches on Arboretum Circle. Proposed Improvements Using the new baseline condition model as the starting point, the proposed Alternative 4 improvements presented in the March 2015 flood study for the Briarcliffe Lakes Subdivision were input into the model for simulation. A total of 3 different scenarios were performed. The first simulation consisted of the Alternative 4 improvements as they were presented in the March 2015 flood study (proposed conditions). Because flood elevation increases occurred at Rice Lake, two alternative were investigated to determine if these increases could be mitigated. The second simulation analyzed these improvements in addition to channel 2 improvements downstream of Rice Lake (proposed conditions and channel improvements). The third simulation analyzed the aforementioned improvements with additional improvements to the Rice Lake outlet weir (proposed conditions, channel, and weir improvements). The results of these analyzes are summarized in Tables 2, 3, and 4, respectively. The location of the cross sections identified in the tables can be seen on Exhibit 4. Table 2: Summary of Existing Conditions vs. Alternative 4 Proposed Conditions Improvements for the Storm of Critical Duration (100-year, 48-hour Storm Event) Proposed Conditions Improvements (100-yr, 48-hr Storm) Peak WSEL (ft) Change in WSEL Location Existing Proposed (ft) RICE LAKE 727.8 727.9 0.13 XS5 720.5 720.5 0.01 XS6 719.9 720.0 0.01 XS7 719.0 719.0 0.01 XS8 717.8 717.8 0.00 XS9 718.3 718.3 0.00 XS10 718.3 718.3 -0.01 XS11 718.3 718.3 -0.01 XS12 718.2 718.2 -0.01 XS13 718.5 718.5 -0.01 XS6.1 725.9 725.9 0.08 XS7.1 721.9 721.6 -0.24 XS8.1 721.5 721.6 0.04 3  Table 3: Summary of Existing Conditions vs. Alternative 4 Proposed & Channel Improvements for the Storm of Critical Duration (100-year, 48-hour Storm Event) Proposed & Channel Improvements (100-yr, 48-hr Storm) Peak WSEL (ft) Change in WSEL Location Existing Proposed (ft) RICE LAKE 727.8 727.9 0.13 XS5 720.5 720.5 0.01 XS6 719.9 720.0 0.01 XS7 719.0 719.0 0.01 XS8 717.8 717.7 -0.05 XS9 718.3 718.3 -0.01 XS10 718.3 718.3 0.00 XS11 718.3 718.3 -0.01 XS12 718.2 718.2 0.00 XS13 718.5 718.5 -0.01 XS6.1 725.9 725.9 0.08 XS7.1 721.9 721.6 -0.24 XS8.1 721.5 721.6 0.04 4  Table 4: Summary of Existing Conditions vs. Alternative 4 Proposed, Channel, & Weir Improvements for the Storm of Critical Duration (100-year, 48-hour Storm Event) Proposed, Channel, & Weir Improvements (100-yr, 48-hr Storm) Peak WSEL (ft) Change in WSEL Location Existing Proposed (ft) RICE LAKE 727.8 727.7 -0.11 XS5 720.5 720.5 -0.01 XS6 719.9 719.9 0.00 XS7 719.0 719.0 0.00 XS8 717.8 717.8 0.00 XS9 718.3 718.3 -0.02 XS10 718.3 718.3 0.00 XS11 718.3 718.3 0.00 XS12 718.2 718.1 -0.04 XS13 718.5 718.5 -0.04 XS6.1 725.9 726.0 0.10 XS7.1 721.9 722.0 0.15 XS8.1 721.5 721.6 0.10 Conclusions Under proposed conditions, the increase in the high water elevation (HWL) of Rice Lake is 0.13 feet, with a maximum increase within the overflow weir section (downstream of the path) of 0.08 feet. Based on our analysis, the water surface elevation has no increases downstream of XS 6.1, once the overtopping flow re-enters the ditch along the west side of Leask Lane. The two alternatives investigated show that there is very little impact to the Rice Lake HWL, and the cross section with an increase of 0.08 ft. However, the first analysis, which is Alternative 4 with no other improvements at Rice Lake shows no negative impacts outside of the Forest Preserve. The Rice Lake outlet is a high hazard Class l dam. It is suggested that the project impacts be verified with the Forest Preserve District and the dam permit conditions such that the shown increases are acceptable. N:\WHEATON\130480\Water\Docs\M1 RiceLakeSummary 122215.docx 5  1 inch = 1,500 feet Roosevelt Rd Naperville Rd 1220 acres 900 acres Butterfield Rd Rice Lake s Lea N:\WHEATON\130480\GIS\Exhibits\Phase 2\EXH 1_Watershed Map.mxd n kL DSGN. JMG CHKD. ELG . CLIENT PROJECT NO. City of Wheaton Christopher B. Burke Engineering, Ltd. 13-0480 B C B 9575 West Higgins Road, Suite 600 Rosemont, IL 60018 (847) 823-0500 / FAX (847) 823-0520 TITLE Watershed Area Map DATE 08/24/15 EXHIBIT 1  1 inch = 400 feet Butterfield Rd s Lea kLn N:\WHEATON\130480\GIS\Exhibits\Phase 2\EXH 2_April 2013 Inundation Map.mxd B DSGN. JMG CHKD. ELG CLIENT PROJECT NO. C . City of Wheaton 13-0480 B Christopher B. Burke Engineering, Ltd. 9575 West Higgins Road, Suite 600 TITLE DATE Rosemont, IL 60018 April 2013 Inundation Boundary 08/24/15 South of Butterfield Road (847) 823-0500 / FAX (847) 823-0520 EXHIBIT 2  1 inch = 400 feet Butterfield Rd Rice Lake 1 2 4 3 5 6 7 N:\WHEATON\130480\GIS\Exhibits\Phase 2\EXH3_April 2013 HWL Locations.mxd s Lea kLn B DSGN. JMG CHKD. ELG CLIENT PROJECT NO. C . City of Wheaton 13-0480 B Christopher B. Burke Engineering, Ltd. 9575 West Higgins Road, Suite 600 TITLE DATE Rosemont, IL 60018 April 2013 HWL Locations 08/24/15 South of Butterfield Road (847) 823-0500 / FAX (847) 823-0520 EXHIBIT 3  ertop 1 inch = 200 feet Legend RICE LAKE v Rice Lake O XSEC_Locations 6 .2 XS 7 .2 XS XS 6 7 XS 1 8 .2 6. S XS 7 S 8 X XS X .1 9 8 XS XS 0 XS 1 1 XS 1 2 XS 1 3 XS 1 4 S 15 ROBINWOOD LN XS 1 X 6 XS 1 7 XS 1 8 XS 1 9 XS 1 0 ARBORETUM CIR XS 2 1 XS 2 2 XS 2 APPROXIMATE SCALE: 1" = DSGN. JMG CHKD. ELG . CLIENT PROJECT NO. Christopher B. Burke Engineering, Ltd. City of Wheaton 13-0480 C BB 9575 West Higgins Road, Suite 600 Rosemont, IL 60018 (847) 823-0500 / FAX (847) 823-0520 TITLE Cross-section Location Map DATE 12/22/2015 EXHIBIT 4 ATTACHMENT 3  1 inch = 300 feet DRAFT Butterfield Rd Rice Lake N:\WHEATON\130480\GIS\Exhibits\Phase 2\EXH 2_50yr48hr Inundation Map_092116.mxd s Lea n kL DSGN. JMG CHKD. ELG . CLIENT PROJECT NO. City of Wheaton Christopher B. Burke Engineering, Ltd. 13-0480 C BB 9575 West Higgins Road, Suite 600 Rosemont, IL 60018 (847) 823-0500 / FAX (847) 823-0520 TITLE Existing v Proposed 50YR, 48HRInundation Boundary South of Butterfield Road DATE 09/21/16 EXHIBIT 2 ATTACHMENT 4  CRITICAL STORM FREQUENCY WHEN HOMES xxx CURRENTLY RECIEVE OVERLAND FLOODING - BRIARCLIFFE LAKES SYSTEM FLOOD STUDY RESULTS xxx FEMA BENEFIT COST ANALYSIS NUMBER (EXISTING CONDITIONS) - HOMES CURRENTLY AFFECTED BY OVERLAND FLOODING IN THE 100 YEAR CRITICAL STORM TOTAL COST = $15,572,849 TOTAL BENEFITS = $80,767,785 BCR = 5.19 2.16 24.49 12.17 1.65 2.28 1.35 N/A 2.33 2.10 4.87 10 10 10 500 25 100 100 25 10 25 25 10 0.35 25 500 25 50 10 10 10 100 25 500 1.40 1.64 0.73 2.70 7.23 12.41 1.95 2.19 0.33 25 50 2.38 500 1.41 0.34 17.14 10 6.42 25 0.52 25 25 0.66 15.71 10 60.52 1.22 1.60 25 1.28 10 25 10 25 25 50 N/A 1.69 0.45 500 50 25 50 1.57 100 25 50 50 500 1.29 1.72 50 0.46 0.45 2.85 25 25 0.74 THE BCA NUMBERS ASSOCIATED WITH THE PROPERTIES IN THIS DIAGRAM WILL VARY BASED ON LOWER LEVEL CHARACTERISTICS SUCH AS AN UNFINISHED/FINISHED BASEMENT OR A LOWER LEVEL FINISHED WALKOUT. ALL INFORMATION PRESENTED IN THIS DIAGRAM IS FROM THE BRIARCLIFFE LAKES SYSTEM FLOOD STUDY PREPARED BY CHRISTOPHER B. BURKE ENGINEERING, LTD.