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HomeMy WebLinkAbout5. 2011 Comprehensive Stormwater Study 09/11/2012Mount Mount Prospect Public Works Department t INTEROFFICE MEMORANDUM TO: VILLAGE MANAGER MICHAEL E. JANONIS FROM: DIRECTOR OF PUBLIC WORKS DATE: SEPTEMBER 5, 2012 SUBJ: 2011 COMPREHENSIVE STORMWATER STUDY FINAL REPORT Background On July 23, 2011, the Village endured a torrential, record - setting, rainfall event that resulted in widespread flooding throughout the community. On August 16, 2011, the Village Board commissioned Burns & McDonnell Consulting Engineers of Downers Grove, Illinois, to analyze the causes of flooding and present their findings in a comprehensive flood study report. Burns & McDonnell was also asked to identify cost - effective recommendations to mitigate defined and recurrent flooding problems. Burns & McDonnell's report was presented to the Village Board at the March 13, 2012 Committee of the Whole meeting. For your reference, the executive summary of this report is enclosed as Attachment A. At over 100 pages, the report was an expansive and compendious examination of the subject. However, the essence of the report can be distilled to the following central themes: The July 23, 2011 rainstorm was an extraordinary event. Analysis of official National Weather Service data indicates that rainfall received in the early morning hours on that day was the most intense ever recorded in the Chicago area. Technically, the storm is considered a "400 + - year" event; a storm that has a 0.25% statistical probability of occurring in any given year. Although technically feasible, constructing sewer improvements to convey a 400 -year storm is cost prohibitive. Conservative estimates place the financial cost of such a feat in excess of $200 million. Burns and McDonnell recommended, and staff concurred, that the most effective and cost - efficient go- forward stormwater management strategy involves a combination of private sector and public sector improvements: 1. Recommended private sector improvements include the disconnection of footing tile drains and the installation of overhead sewers in the 379 homes that reported sanitary backup. These improvements will eliminate the prevalent pathway for sanitary sewer water to enter basements and below -grade living spaces — the gravity drain. In many cases, these improvements will also eliminate the Page 2 of 4 2011 Comprehensive Flood Study Report September 5, 2012 introduction of clear water into separate sanitary sewers. The estimated cost of this work is $9,475,000. 2. Recommended public sector improvements include the installation of larger pipes, and /or the construction of relief sewers, at specified locations. These improvements will be constructed where engineering evaluation revealed severe and geographically concentrated flooding associated with a pronounced lack of local sewer conveyance capacity. Improvements will be designed to provide a 25 -year level of protection. The estimated cost of this work is $14,440,000. 3. Four (4) drainage basins were identified that warrant additional engineering evaluation. The estimated cost for this work is $28,000. The total cost for all improvements recommended by the attached 2011 Comprehensive Stormwater Study is $23,943,000. Further discussion on the subject was conducted, and additional public comment was received, at April 10, 2012 Committee of the Whole meeting and the May 22, 2012 Committee of the Whole meeting. As a result of this discussion, two (2) additional potential public improvement projects were identified to help mitigate surface- induced flooding on Blackhawk Drive and on Lawrence Lane. (Note: Subsequent to the May 22 meeting, staff prepared plans and cost estimates for both the Blackhawk Drive and Lawrence Lane improvements. The Blackhawk Drive improvements are estimated to cost $400,000. The Lawrence Lane improvements are estimated to cost $50,000.) Incorporating the cost of these additional projects, the cost of recommended public sector improvements increases to $14,890,000; the overall cost of all recommended improvements increases to $24,393,000. At the May 22, 2012 Committee of the Whole meeting, the Village Board remanded the matter to the Finance Commission with a directive to identify potential sources of funding for the recommended improvements. The Finance Commission considered this charge at meetings held on May 23, 2012, July 23, 2012 and July 26, 2012. The Finance Commission's final recommendations are detailed in the minutes of their July 26 meeting. For your reference, a copy of these minutes is enclosed as Attachment B. The Finance Commission's final recommendations were presented to the Village Board at the August 21, 2012 Regular Meeting. In summary, the Finance Commission recommended a multi -year, phased approach to constructing the recommended public sector improvements at an expenditure level of approximately $1.2 million per year. They proposed to fund this level of expenditure by creating a new Special Service Area or extending the soon to expire term of Special Service Area #5. The Finance Commission also recommended funding the private sector improvements at a level of approximately $300,000 per year to be generated by increasing the sewer construction fee from $5 to $7 per billing period. They also opined that private sector improvements should be facilitated by means of low interest loans repayable upon the sale of the improved property. They further suggested that the loans should only be made for maximum of two - thirds (2 /3rds) Page 3 of 4 2011 Comprehensive Flood Study Report September 5, 2012 the cost of the project with the balance of the funding supplied by the property owner. Funds to be made available upon a first come first served basis and limited to property owners with demonstrated flooding histories. More recently, as part of preparations necessary to develop financial forecasts for budgeting purposes, Finance Director David Erb has determined there is sufficient capacity in existing revenue streams to fund approximately $2.5 million worth of recommended improvements in the short term. Specifically, Mr. Erb advises that existing home rule sales taxes begin to become available from expiring Illinois Environmental Protection Agency (IEPA) loans after 2013 and can be reallocated to support annual debt service payments on a new short -term note. Current market interest rates on a 7 -year note are 1.73 %. If sanctioned by the Village Board, debt can be issued in fiscal (calendar) 2012 and fiscal (calendar) 2013 in amounts totaling $2.5 million. This funding can be utilized to construct the Hatlen Heights Stormwater Improvements ($1.5 million), Hatlen Heights Sanitary Improvements ($105,000), Lonnquist Combined Sewer Improvements ($200,000), Lonnquist Storm Sewer Improvements ($135,000), Blackhawk Drive Stormwater Improvements ($400,000), Lawrence Lane Storm Sewer Improvements ($50,000), and the recommended additional engineering studies ($28,000). All of these projects are nearly "shovel- ready" and can be started in 2013. The sole remaining public sector improvement, Isabella Street Area Combined Sewer Improvements ($12,500,000) cannot be financed without the issuance of general obligation bonds and the development of a mechanism to facilitate debt service. Discussion Staff seeks Village Board direction on the following items: Is there support for Village participation in the cost of private sector improvements (footing tile disconnection and overhead sewer installation)? a. If there is support, at what level? Should the Basin 14 model be applied? (50% grant, 50% simple- interest loan payable upon sale of the home, $18,000 cap per home.) Should the Finance Commission model be applied? (No direct grants; assistance limited to low- interest loan capped at 2/3 rd cost of improvements.) iii. If the Basin 14 model and the Finance Commission models are inadequate, how should the Village participate in the cost of private sector improvements? 2. Several property owners affected by the July 23, 2011 flood have subsequently installed overhead sewers and removed footing tile connections. Should these property owners be retroactively eligible to access Village financial aid? Page 4 of 4 2011 Comprehensive Flood Study Report September 5, 2012 3. Is there support for issuance of short -term debt to facilitate the construction of approximately $2.5 million worth of public sector improvements? (Debt service provided by additional capacity from % cent sales tax due to the retirement of IEPA loans.) 4. Is there support for the issuance of long -term debt (G.O. bonds) to facilitate the construction of the remaining public sector improvement (Isabella Street Area Combined Sewer Improvements) at an estimated cost of $12,500,000? If so, how should debt service be facilitated? Recommendation With your concurrence, staff asks that this matter be presented for the Village Board's consideration at the September 11, 2012 Committee of the Whole meeting. Sean P. Dorsey Cc: Assistant Village Manager David Strahl Finance Director David Erb Village Clerk Lisa Angell Deputy Director of Public Works Jason Leib Water /Sewer Superintendent Matt Overeem File SPD /spd is \my documents \special events \storm july 23 2011 \september 11 2012 cow\2011 comprehensive flood study sept 11 2012 cow.docx Attachment A EXECUTIVE SUMMARY The Village of Mount Prospect (Village) contracted Burns & McDonnell Engineering Company, Inc. (Burns & McDonnell) to determine the reasons for the significant impacts to the Village that occurred with the July 23, 2011 storm event and identify potential improvements to the Village's stormNyater management system that would help to diminish the impact that a future storm of this magnitude would generate. The Village provided storm flood survey information to Burns & McDonnell which was gathered from the residents through an extensive public outreach program. This outreach program included having Village employees and Burns & McDonnell representatives visiting residents' homes or contacting them via telephone to gather information regarding the magnitude and type of flooding experienced by each affected resident. Further, the intent of the study was to quantify and analyze the various drainage basins within the Village based on the findings of the flood surveys. Using the information gathered, areas that experienced the highest density of flooding were selected to be studied in greater detail using hydraulic modeling soffiyare. Basins that were not modeled were analyzed based on the types of flooding reported in each area. This study is intended to serve as a tool to assist the Village in evaluating and prioritizing capital improvements and in maintaining its storm and combined seNver system, as well as its separate sanitary sewer system. It is important to emphasize that the July 23r storm was an extreme rain event in terms of rainfall intensity and quantity. According to the hourly rainfall data obtained from the rain gauge at Chicago O'Hare International Airport, a total of 6.78 inches of rain fell during the peak 3 hours of the storm. Over a 24 hour period, a total of 8.27 inches of rain fell over the area. The storm can be classified as approximately a 400 -year storm (or a storm that has a probability of occurring once even* 400 years) based on the 3 -hour peals intensity and volume of rainfall. Current industry standard is to design a typical storm sewer system to handle a 10 -year storm event using Bulletin 70 Rainfall Data. Much of the Mount Prospect storm and wastewater collection system was constructed prior to when these standards were implemented, and as such, may have a lower conveyance capacity. This circumstance is typical for older communities including the City of Chicago and most "inner ring" suburbs. Therefore, flooding of the local conveyance system during a storm with a magnitude like that of the July 23 2011 storm is unavoidable. A logy end conservative estimate of the capital cost to mitigate the flooding from an event similar to the July 23r storm using public sector improvements only is in excess of $200,000,000. This cost would include the construction of relief storm seNvers, combined relief seNvers, underground detention, sanitary relief stations and other related improvements. Purchasing property to create additional detention would increase these costs further. Additional operation and maintenance costs would also be incurred by the Village. Even with all these improvements, protection against seNver backups from a storm event similar to the July 23 2011 event would not be as reliable as private property improvements such as installing overhead plumbing or backup prevention systems. The Village performs a ven- thorough maintenance and flood relief effort on an ongoing basis. Inspections of the storinwater system outfalls at detention basins and creeks are made on a twice a year Village of Mount Prospect ES - 1 February 2012 Stormwater Management Study Attachment A basis. In addition each of the Village's wastewater collection system basins is inspected and maintained on a regular and systemic basis. Further, since 1990, the Village has spent over $25,000,000 in flood relief improvements, and has significantly reduced infiltration and inflow of stormNvater runoff to its separate sanitary seNver system. These efforts have provided a significant benefit to the Village; greatly reducing the frequency and magnitude of flooding incidents. Nevertheless, sanitary backups and surface flooding occurred in many of the areas where improvements have been made simply due to the magnitude of the July 23 2011 storm event. While there are areas where frequent surface flooding can be diminished by upgrading the public conveyance systems, the most effective solution to minimize sanitary backup is to make private sector improvements. Malting strictly public sector improvements is cost prohibitive, and there are likely structural integrity and capacity issues in private sector piping that would still remain problematic even if the public sector seNver main could accept all of the water. Further, the MWRDGC receiving system has a limited capacity. Increasing the capacity of the Village's sewers may be rendered ineffective by restrictions caused by the MWRDGC receiving system. It is important to note that neither public nor private sector improvements will alleviate all flooding should an event similar to the July 23 rainfall occur. Private sector improvements that can be made to mitigate flooding impacts include the following: • Disconnection of foundation drains and installation of overhead plumbing in 379 buildings /homes that reported sanitary backup. • Inspection and repair of foundation Nvalls through which seepage occurred in 177 buildings /homes. • For the 203 properties that experienced surface flooding during the July 23 storm event, inspection of property drainage including all gutters, downspouts and locations of sump pump discharge to matte sure that surface drainage is directed away from the residence. This may also help minimize seepage. • For the 142 properties where sump pump failure was experienced inspection of the sump pump system to matte sure that it is working and has adequate capacity. After completion of the inspection install a secondary sump pump, if needed, and a battery backup and /or emergency generator if system. The budgetary cost for the disconnection of foundation drains and the installation of overhead plumbing in 379 buildings /homes is $9,475,000, based on an average cost of $25,000 per building /home. Development of costs for mitigating flooding resulting from sump pump failures through the installation of a secondary sump pump and an emergency battery backup and /or emergency generator for the 142 buildings /homes that reported sump pump was not determined as part of this study. It is recommended that each property owner contact a company that specializes in providing sump pump inspections and emergency generator installation to mitigate sump pump failures. Village of Mount Prospect ES - 2 February 2012 Stormwater Management Study Attachment A Cost for mitigating flooding from seepage and private sector surface flooding in these basins Nyas not determined as part of this study. It is recommended that each property owner contact a company that specializes in mitigating basement flooding caused by seepage. Based on the results of the flooding questionnaires, additional assessment and hydraulic modeling Nyas performed for several areas N-, the most severe and geographically concentrated amount of flooding occurred. Based on this additional assessment improvements to upgrade the capacity of the existing combined and separate seNver systems Nyere developed. Budgetary costs for implementing these public sector improvements are $14,440,000. Several separate seNyer areas Nyere also identified for additional assessment. These areas have a relatively loNy occurrence of reported flooding; hovyever several localized areas of concentrated flooding Nyere reported. A budgetary cost for completing the recommended evaluations is $28,000. Cost Summary The total budgetary cost to implement the recommendations presented in this study is $23,943,000. A brealcdoN -,n of these costs is presented in the folloNving table. Summary of Recommended Stormwater Management Improvements Area Type of Improvement Improvement Budgetary Cost Haden Heights Storm SeNver Improvements for 25- Public Sector $1,500,000 Subdivision year Level of Service Haden Heights Sanitary SeNver Improvements for Public Sector $105,000 Subdivision 25 -year Level of Service Combined SeNver Improvements for Isabella Street Area Public Sector $12,500,000 25 -year Level of Service CS31 Combined SeNver Lonnquist Boulevard Public Sector Improvements for 25 -year Level of $200,000 Area Service Lonnquist Boulevard Public Sector Adding Inlets and Televising $135,000 Area Disconnection of 379 Foundation Village -Nyide Private Sector $9,475,000 Drains Nvith Overhead Plumbing Further Investigation Basin SS21, Basin SS41, Basin and Additional $28,000 SS45 and Illinois American Basin Analysis Total $23,943,000 Village of Mount Prospect ES - 3 February 2012 Stormwater Management Study Attachment B FINANCE COMMISSION Minutes of the Meeting July 26, 2012 I" Floor Community Center Village Hall L Call to Order The meeting was called to order at 7:20 p.m. Those present included Chairman Vince Grochocinski and Commissioners, Pam Bazan, Tom Pekras and Ann Smilanic. Commissioners Wayne Gardner, John Kellerhals, and Don Ocwieja were absent. Also present was Finance Director David Erb. IL Approval of Minutes May 23, 2012 - Minutes of the meeting were reviewed. Commissioner Pekras motioned to approve the minutes. Commissioner Bazan seconded the motion and the minutes were approved. July 23, 2012 - Minutes of the meeting were reviewed and amended to include the results of the vote taken at the meeting. Commissioner Bazan motioned to approve the minutes. Commissioner Pekras seconded the motion and the minutes were approved as amended. III. Citizens to be Heard There were no citizens to be heard. IV. Old Business Capital Projects Funding Alternatives - Building on the discussions during prior meetings, where all members of the commission were present, Financial Director Erb presented a summary of these discussions and the general agreements of the commission members in order to facilitate continued discussions. The funding discussions considered the following 1. Street improvement projects 2. Flood control projects 3. Emerald Ash Bore (EAB) 4. Automated meter reading 5. Randhurst incentive funding The principles governing the Commission's search for funding sources were 1. Funding sources should reflect direct association with use of the funds as far as possible. 2. Sources of funds should distinguish between on -going needs as distinct from periodic needs, i.e., street resurfacing is on -going each year while flood control activities are periodic projects. 3. Incurring debt should be used sparingly to protect the Village credit rating. 4. Sales taxes should not be increased. Earlier discussions by the Commission recognized the following 1. Randhurst incentive funding requires issuing targeted debt with specifics understood following ideas expressed when negotiating the original agreements. 2. The EAB cost for removal and replacement of Village trees should be funded from current sources, some grant assistance and homeowner participation in replacing their parkway trees. 3. Automated water meter reading costs should be included in the calculation of water usage rates as has already begun. It was agreed that the on -going street improvement needs should take priority over the flood control issues, but not to the complete exclusion of certain of the anticipated flood prevention projects. The Commission considered circumstances regarding the street improvement needs etc. 1. The 10 miles of backlogged street resurfacing would cost in excess of $5 million if it were to be resolved in a single project, and as long as the backlogged inventory is rotated to prevent the roads going into reconstruction mode, there is no pressing need to have such a catch up project. 2. The funding needs are continual and must prevent the backlog from growing to the extent that reconstruction is then needed. 3. The practice of using funds intended for resurfacing to handle other road related projects while using only left over funds for resurfacing to the extent available should be discouraged. 4. Combining for display purposes only the Street Improvement Constriction Fund (SICF) and the Motor Fuel Tax Fund (MFTF), since both are used to resurface roads, the additional funds needed are estimated at $1.5 million per year. 5. The current funding sources for the SICF and MFTF are: State allocation of motor fuel taxes; home rile tax of $.02 cents per gallon; and '/4 cent of the home rile sales tax. 6. The Commission agreed upon the following funding sources and amounts: a. Add $.03 cents to the local motor fuel tax (from $0.02 to $0.05). Yields $510,000 b. Increase the basic vehicle sticker $14 from $36 to $50. Yields $540,000. c. Divert the surplus from the '/4 cent home rile sales tax now funding the flood control projects and debt payments to the SICF. Yields start at $250,000 the first year and increases to $1.4 million per year over several years. On -going flood projects would still be funded from this sales tax while project type sewer work is fund by issuing debt. The flood control study was reviewed it was decided to fund the $14.4 million in public improvements via the issuance of debt. Note that the one major project already in the Capital Improvement Plan is duplicated in the $14.4 million and is thus eliminated from the need to use the home rile sales tax to handle the funding. 2 The debt issued for the flood projects should be repaid via the use of two special service areas which will either include or exclude the area not served by Village water and sanitary sewers. The impact on real estate taxes will be minimize by the fact that Special Service Area 5 debt is expiring soon and will be replaced by the new debt being recommended. Private improvements such as overhead sewers, backup prevention devices, disconnection of foundation drains etc. would not include any public subsidies. Instead, a funding source would be created by increasing the monthly Sewer Constriction fee from $5 to $7 per month. Funds generated from this additional tax total $320,000 per year which would be used to fund low interest loans to residents who certify that they have had water in their home subsequent to and including the date of last year's flooding. The resident would pay 1/3 of the cost up front and the Village would loan the other 2/3 with the loan to be repaid no later than the sale of the home. Home owners would be urged to take self serving actions such as stand pipes, backup battery powered sump pumps, wall crack sealing and flood and water backup insurance which are not included in this loan program. The Village should prepare pamphlets on this subject and have a list of licensed contractors available. Commission Pekras made a motion to make the above recommendations to the Village Board of Trustees. Commissioner Bazan seconded the motion and the motion passed unanimously. Note that Commissioners not present at this meeting where in general agreement with these conclusion as expressed in prior meetings. Commissioner Kellerhals did not favor the increase to the cost of the vehicle sticker. He did though recommend a $0.05 cent increase to the Village gasoline tax. V. New Business Mid -year Budget Review - Finance Director Dave Erb presented the results of the comparison of six months of actual receipts and disbursements for 2012 to the budget and the impacts on the full year results and the forecast budget for 2013. Overall, revenues are projected to come in over budget by $404,000 while expenditures increased slightly by $186,914. If the projections hold through the end of the year the surplus of $122,342 will go towards maintaining the General Fund fund balance. Annual Audit 2010 Review - Finance Director Dave Erb presented the results of the 2010 audit and related auditor comments and management letters. No concerns of great magnitude were noted. The auditor gave the village audit a clean opinion for its financials as of December 31, 2011. VI. Other Business There was no other business. VII. Chairman's Report There was nothing to report. 3 VIII. Finance Director's Report There was nothing to report. IX. Next Meeting: Au 23, 2012 Commissioner Pekras motioned to give the Chairman authorization to cancel this meeting depending on the business to be discussed. Commissioner Bazan seconded the motion and the motion carried. X. Adjournment Commissioner Smilanic motioned to adjourn. Commissioner Tom Pekras seconded the motion which passed. The meeting was adjourned at 9:15 p.m. Respectfully Submitted, Vince Grochocinski