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HomeMy WebLinkAbout98-137 Resolution No. 98-137 RESOLUTION ACCEPTING THE WATER ACCOUNTABILITY EVALUATION REPORT OF ALVORD, BURDICK & HOWSON, L.L.C. AND DIRECTING IMPLEMENTATION WHEREAS, the City Council directed an evaluation be made of the water department' s water accountability system; and WHEREAS, on May 27, 1998, the City Manager delivered this report and recommendations. NOW, THEREFORE, BE IT RESOLVED BY THE CITY COUNCIL OF THE CITY OF ELGIN, ILLINOIS, that it hereby accepts the report and directs the City Manager to take action necessary to implement the recommendations of the Water Accountability Evaluation Report prepared by Alvord, Burdick & Howson, L.L.C. and dated May 1998. s/ Kevin Kelly Kevin Kelly, Mayor Presented: June 10, 1998 Adopted: June 10, 1998 Omnibus Vote: Yeas 7 Nays 0 Attest: s/ Dolonna Mecum Dolonna Mecum, City Clerk 4.(0 EtCj Co• � " Agenda Item No j City of Elgin : May 12, 1998 TO: Mayor and Members of the City Council FROM: Joyce A. Parker, City Manager SUBJECT: Acceptance of the Water Accountability Evaluation Report PURPOSE The purpose of this memorandum is to provide the Mayor and members of the City Council with information to accept the water accountability report prepared by Alvord Burdick & Howson, LLC. BACKGROUND On January 14, 1998, the Elgin City Council awarded the project of,. -evaluating the Water Department ' s water account- ability system to Alvord Burdick & Howson for $14 , 900 . The department ' s water accountability was averaging 806, and the department was concerned as to any unaccounted water as well as the systems in place to track water accountability. This report provides recommendations for improved water accountability (see attachment A) . Also attached is exhibit B regarding actions to be taken by the Water and Finance Departments as the result of recommenda- tions in the study. Based on the estimate for quantities unaccounted for in 1997, Alvord Burdick & Howson estimates that, rather than an account- ability factor of 806 for 1997, in fact, the value was closer to 876 . The primary reasons for the change in the account- ability level include the application of Illinois Department of Natural Resources (IDNR) standards for "unavoidable" underground water loss (4 . 26) , water usage data reporting adjustments to include additional usage categories ( . 9%) , adjustments to allow for certain waste streams at the treatment plants ( . 66) , and a software reporting issue ( .46) . It is the firm' s view that acceptable accountability for older water systems such as Elgin' s would be 80 to 856 . COMMUNITY GROUPS/INTERESTED PERSONS CONTACTED None . Water Accountability Evaluation May 12, 1998 Page 2 FINANCIAL IMPACT Remaining payments for the $14 , 900 professional services contract will be made from account number 401-4002-771 . 30-03 , Architectural and Engineering Services . LEGAL IMPACT None . 441--- ALTERNATIVES None . RECOMMENDATION It is recommended that the City Council accept the water accountability evaluation by the engineering firm of Alvord Burdick & Howson. Respectfully submitted, rft. Jo e . Parker City Manager LED:j m Attachments MEMORANDUM rft. TO: Joyce A. Parker, City Manager FROM: Larry E. Deibert, Director of the Water Department L ) DATE: May 14, 1998 SUBJECT: WATER ACCOUNTABILITY FOLLOW-UP Following is a list of items and actions to be taken by the Water and Finance Departments in response to the Summary of Recommendations from the study on water accountability produced by Alvord Burdick & Howson. 1. Unavoidable underground water loss be included in Elgin's water accountability calculations using IDNR's standards. Response: This calculated 4.2% unavoidable loss will be incorporated into the water accountability report. 2. Information on water used under the "Irrigation," "Construction," and "Pool" categories be included in the data provided to the Water Department monthly by the Finance Department. Response: Finance Department to include this information. 3. Water use summaries produced by the utility billing software be manually verified before being used for water accountability calculations. Response: Finance Department to make this manual verification. 4. Finance Department make water consumption adjustment information available to the Water Department monthly in the "City Manager's Operating Summary" report spreadsheet, which is used to calculate water accountability, be modified to account for these adjustments. Response: Finance Department has begun to submit these adjustments prior to the "City Manager's Operating Summary" being published. 5. The Water Production Spreadsheet be modified to account for waste streams identified at the Riverside plant. Response: The spreadsheet at the Riverside plant will be modified as improvements are completed. 6. Water used for surface wash at the Riverside plant be deducted when calculating water supplied to the low service zone since it is withdrawn after low service zone effluent meter. Response: Spreadsheet has been modified to deduct this amount of emk water. 7. A meter be installed on the 6" nonpotable water main that supplies finished water to chemical feed systems at the Airlite plant. This consumption will be considered in future water accountability. Page 2 Response: An addendum was issued to the construction bid for the Airlite plant. Installation of a water meter will be completed within the Seagren & Shales contract. 8. The accuracy of the influent and effluent meters at the Riverside and Airlite plants be verified at least once a year as a policy. Response: As a minimum, these meters will be verified at least once annually. 9. The ongoing Water Department AMR quality review program, which is expected to be completed in May, be undertaken at some level periodically in order to ensure the integrity of the AMR system. Response: The initial system-wide AMR quality review has been completed. Specific review items have been identified by the Meter Shop supervisor that initially will be reviewed monthly. Pending results of this program, the time period may be extended to quarterly. 10. After all accounts have been converted to the AMR system, monthly water use data to be utilized for water accountability calculations be generated by the Water Department utilizing data directly from the AMR system. Response: This issue will be reviewed once all meters that can be converted to the AMR system are, in fact, converted. The question as to how many meters may not physically be able to be converted to AMRs, and how to include them in the accountability calculations will be addressed then. 11. Adjustment be made for service meter inaccuracy for water accountability purposes. Response: Since 1991 72% of the City's water meters 25,531 have been replaced. It is felt that this proposed adjustment is insignificant and will not be incorporated into the accountability study. Furthermore, as it is anticipated that the AMR conversion program will be completed in three years. These recommendations will be incorporated in a reformatted June monthly water accountability report. LED:jm 01200511.298 cc: Kurt M. Eshelman, Water Plant Superintendent Kyla B. Jacobsen, Chief Water Chemist Carl Freund, Water Meter Supervisor Pat Oglesbee, Water Distribution Superintendent James R. Nowicki, Finance Director e • REPORT 1. F r FLumitus Z -- ;7.* AVA7,„,-.0,,,, co • 0,9 '--,441 TED MAY 1998 _ LVORD BURDICK & HOWSON L C 9 • • • &H -L-T NG ENGifsfEE-RS---Sitie;L AJtit-e- ALVORD, BURDICK & HOWSON, L. L. C. ENGINEERS 20 NORTH WACKER DRIVE•SUITE 1401 SERVICES MEMBERS WATER WORKS,WATER PURIFICATION CHICAGO.IL 60606 AMERICAN SOCIETY OF CIVIL ENGINEERS WASTE WATER COLLECTION TEL.19121 236-9147 FAX:13121 236-0692 WESTERN SOCIETY OF ENGINEERS FLOOD RELIEF S AMERICAN WATER WORKS ASSOCIATION JOHN W.ALVORD CHARLES B.BURDICK LOUIS R.HOWSON POWER GENERATION CHICAGO ASSOCIATION OF INVESTIGATIONS.REPORTS AND PLANS 1861-1849 1874-1968 1887-1985 COMMERCE AND INDUSTRY CONSTRUCTION AND OPERATION SERVICES DONALD E.ECKMANN DR.YA-TAI LIN NATIONAL ASSOCIATION OF APPRAISALS AND RATE REPORTS J.WARREN GREEN BON G.MUI DR.RAY S.T.CHENG CORROSION ENGINEERS x-- JAMES W.HEDGES WILLIAM L.MEINHOL2 RICHARD D.SHEA WATER ENVIRONMENT FEDERATION AMERICAN PUBLIC WORKS ASSOCIATION AMERICAN CONSULTING ENGINEERS COUNCIL May 8, 1998 Mr. Lary E.Deibert Director of the Water Department 150 Dexter Court Elgin,IL 60120-5555 • Re: Water Accountability Evaluation Dear Mr.Deibert: In accordance with our Contract Agreement,we have completed an evaluation of the City of Elgin's water accountability program and are pleased to submit herewith our report. In performing the study,we surveyed the existing systems utilized to monitor water use, and the reliability and adequacy of the systems used to determine overall water production and accountability. We reviewed the City's historical accounted-for water data over a 13 year period; reviewed meter installation,reading and testing programs;reviewed the water billing program; and reviewed numerous other data provided by the City. We also had several interviews with the staff of the Water and Finance Departments and visited water treatment and distribution facilities. Our findings and recommendations are summarized in the"Executive Summary" section of this reptirt. • The water accountability committee and the staff of the Water and Finance Departments contributed to the successful completion of this study. The input of the water accountability committee and the timely response of the Finance and Water Departments to our requests for information and interviews enabled us to complete this study on time.And results of the Water Department's internal investigation to assess the performance of the Automatic Meter Reading (AMR)system provided much useful information and aided in our understanding of how the • �7y Elgin meter reading'and bi ling systems work. We greatly appreciate the cooperation of the committee and the two departments. 1 of Alvord,Burdick&Howson reciates the opportunity of serving the City of The firm o o d, app pp ty g tY Elgin on this important project. Respectfully submitted ALVORD,BURDICK&HOWSON,L.L.C. William G.Nyanue,P.E. Bon G. Mui,Partner • • r t Table of Contents Chapter Title Page Letter of Transmittal I Executive Summary 1 II City of Elgin Water Supply System 8 III Review and Evaluation of Existing 10 Water Accountability Program IV Review and Expansion of the Night Rate Analysis Program 26 L r C List of Tables C Table No. Title Page 1 Riverside Meters Testing History 12 2 Facilities Included in the Water Production Spreadsheet 14 3 Comparison of Finance and Water Departments' "Water Billed" Data for 1997 18 4 Comparison of Computer Generated and Manually Added Consumption Range Totals 19 5 Facilities Included in Current Minimum Night Night Rate Analysis Spreadsheet 26 List of Figures Figure No. Title After 1 Elements Included in Water Accountability Program Page 10 2 Accounted-for and Unaccounted for Water Page 11 3 Flow Diagram of Water Supply System Page 13 4 Flow Diagram of the Riverside Water Treatment Plant Figure 3 L r CHAPTER I EXECUTIVE SUMMARY INTRODUCTION The City of Elgin contracted the services of Alvord, Burdick&Howson to perform an evaluation of its water accountability program. The objective of the study was to evaluate the adequacy and accuracy of means and methods utilized to monitor water accountability. The tasks to be performed included: 1. Surveying the existing systems utilized to monitor water use that provide billing information in the City of Elgin. 2. Evaluating the reliability of those systems that are used to determine overall water production, use and accountability. 3. Making recommendations for system improvements in means and methods to improve accountability. 4. Reviewing and updating water operation computer spreadsheets of water accountability. 5. Reviewing and updating water operations two pressure zone minimum night rate analysis programs and developing third pressure zone minimum night rate analysis program. SUMMARY OF FINDINGS AND RECOMMENDATIONS To evaluate the Ci ty of Elgin's water accountability program,we reviewed water production and use data over a 13 year period; reviewed the City's meter installation, reading and testing programs; reviewed the water billing program;had several meetings with staff of the City's Water and Finance Departments; visited water treatment and distribution facilities; and applied AWWA's water accountability requirements. Following is a summary of our findings and recommendations. tig A. Water Accountability 1. The City of Elgin's accounted-for and unaccounted-for water during the past 13 years are illustrated in Figure 2 in Chapter II. On the average, about 80%of water produced during this period was accounted-for. The accountability would improve to 87%when the recommendations of this study are implemented. The AWWA recommends accountability of more than 90% for well-maintained new water supply systems. In our experience, acceptable accountability for older systems, such as Elgin's,would be 80 to 85%. 0 1 00 r 2. In general,the City of Elgin's water accountability program is well thought out. The sophistication of the computer spreadsheets utilized to track water through the water system and to perform water accountability calculations indicate that much thought and effort was put into developing the program. No deficiencies were found in the logic of the program. 3. The current practice of water accountability does not account for unavoidable underground leakage,which is impossible to totally eliminate in a distribution system. The Illinois Department of Transportation(IDOT),now Illinois Department of Natural Resources (IDNR),has determined a level which it believes is reasonable and allows all municipalities receiving Lake Michigan water to include in their calculations of water accountability. It is recommended that this underground water loss be included in Elgin's water accountability , calculations,using IDNR's standards. This water loss would amount to approximately 198 MG annually(0.542 MGD), or 4.2%of water produced in 1997. 4. Water consumption data used to calculate monthly water accountability is provided by the Finance Department as part of its "Consumption by Range" report. The report is generated based on meter reading data provided by the Water Department(for AMR accounts) and Water Services, a private contractor, for non-AMR accounts. Following are our findings and recommendations based on a review of water use information provided by the Water and Finance Departments: a. Meter reading data is reported to the Finance Department in cubic feet. The conversion to water billing units of hundred cubic feet was correctly done for all the accounts which were reviewed. b. There were discrepancies in the total monthly"water consumption" and "accounts billed" figures generated by the Finance Department computers and reported as part of the "Consumption by Range" report. The total water used in 1997 based on the monthly "Consumption by Range" reports was approximately 18 million gallons(0.4%of water produced in 1997) lower than the total based on manually adding the monthly water consumption figures. The discrepancies for the 1997 data were less than 1% and may be due to the accuracy of the consumption by range utility program. However, there was no data available to verify if in fact the utility billing software is reporting the correct water use data for each range of consumption. The developers of the program have indicated that they were aware of the problem and that it is being corrected in the improved version of their utility billing software. 2 EPP r The City will be converting to an improved water billing program in 1998. Therefore, it would not be prudent to further invest in the current program. However, it is recommended that in the meantime consumption summaries produced by the current consumption by range utility program be manually verified before being used for water accountability calculations. c. "Water consumption" data which the Finance Department provides to the Water Department monthly as part of the "Consumption by Range" report and which is used by the Water Department to calculate water accountability does not include water used under the "Irrigation," "Construction," and "Pool" categories. During 1997, approximately 43 MG(0.9% of water produced in 1997) of water used under these three categories were not included in the calculation of water accountability. It is recommended that this information be included in the data provided to the Water Department monthly. d. There are some discrepancies between the monthly "water consumption" data which is used by the Water Department to calculate water accountability and Finance Department's data for the same period(See Table 3 in Chapter III). These discrepancies are due to consumption adjustments which are made after the "water consumption" data has been sent to the Water Department. On the average, about 30 water consumption adjustments are made weekly but the revised data is not communicated to the Water Department. It is recommended that the Finance Department make this adjustment information available to the Water Department monthly and that the "City Manager's Operating Summary" report spreadsheet,which is used to calculate water accountability,be modified to account for these adjustments. 5. The Water Department calculates monthly water production data utilizing a computer spreadsheet. The formulas and spreadsheet operations employed to calculate monthly water productions were found to be correct. However,the spreadsheet was found to be missing the following waste streams at the Riverside and Airlite Water Treatment Plants: a. Water used to supply chlorine solution to the six deep wells located at the Slade Avenue Facilities (approximately 2 MG in 1997). b. Flows through 5 turbidimeters, 1 chlorine residual analyzer and plant sampling taps for water quality control (approximately 7 MG in 1997). c. Surface wash water at the Riverside plant. Even though this water is recycled, since it is withdrawn after the Low Service Zone effluent meter 3 r (see Figure 4 in Chapter III), it should be deducted when calculating water supplied to the Low Service Zone (approximately 4 MG in 1997). d. Water which backflows from the distribution system into the Airlite plant. The backflow occurs when high service pumps at the plant are turned off. Currently, there are no means available to measure this backflow. However,based on raw and finished water data it was estimated that approximately 14 MG of back flow occurred in 1997. It is recommended that a meter be installed on the 6" non-potable water main through which the backflow is occurring to permit deduction for future water accountability. o The above listed waste streams and backflow amounted to 0.6%of water produced in 1997. It is recommended that the Water Production Spreadsheet be modified to account for this water loss. 6. Based on estimates of waste streams identified at the Riverside and Airlite Water Treatment Plants and discrepancies with the "Consumption by Range" report, approximately 88 MG of water used in 1997 were not included in the calculation of water accountability. If the 1997 total water use figure is adjusted to account for this water and unavoidable underground leaks (approximately 198 MG),the annual water accountability would improve from approximately 80%to about 87%. 7. Data used to calculate monthly water production includes readings of influent and effluent meters at the Riverside and Airlite Water Treatment Plants and the Lyle and Slade Avenue booster facilities. The accuracy of these meters would impact the calculation of water production figures. It is recommended that, as a policy, the accuracy of these meters be verified at least once a year. 8. There are 25,000 water accounts in the Elgin water supply system, about 18,000 of which utilize Badger's Telephone In-Bound Automatic Meter Reading(AMR) technology. Based on results of an internal Water Department investigation, it was determined that 7 (0.04%) of the AMR meters were improperly installed. As a result,the AMR system was reporting only 10%of consumptions for the 7 accounts. An additional 250 (1.4%) of the AMR meters were programed with duplicate serial numbers which resulted in the AMR system reporting data that was incompatible with the utility billing software. The investigation has been completed and the problems identified have been corrected. In order to ensure the integrity system,the AMR s stem, it is recommended that the just ended Water Department AMR Quality Review program be undertaken at some level periodically. 4 i ; PP 9. Under current practice, the determination of water use data involves the Water Department, the Finance Department, Water Services and the transfer of information between these entities. This represents a potential for data processing errors. Currently,the Water Department receives monthly water consumption data for the 18,000 AMR accounts and the remaining 7,000 accounts are to be converted as part of the on-going AMR program. After all accounts have been converted to the AMR system, we would recommend that monthly water use data to be utilized for water accountability calculations be generated by the Water Department,utilizing data directly from the AMR system. This practice will not only minimize the potential for data processing errors,but would make the monthly water use data more compatible with the monthly water production data. Under the current system, the water use data represents bimonthly consumptions. Based on a City request,Badger has made provisions in the AMR system for easy retrieval of total monthly water use data. 10. The determination of total metered water use is impacted by the accuracy of service meters. For the purpose of water accountability, the AWWA recommends that adjustments be made to raw meter readings to account for service meter errors. The current City of Elgin water accountability practice does not include adjustments for service meter errors. In order to more accurately determine metered water use, it is recommended that adjustments be made for service meter errors. The adjustment factors should be determined based on procedures outlined in "Water Audits and Leak Detection" (AWWA M36), published by the AWWA. B. Minimum Night Rate Analysis Program The Minimum Night Rate Analysis program is a component of a Water Department program which monitors water used from the distribution system on an hourly basis. The Minimum Night Rate Analysis program tracks water use in the Low and High Service zones on Sundays,between the hours of 2:00 A.M. and 4:00 A.M., when water use is assumed to be at a minimum. The results of the program are used to detect unusually high water demand which could be due to leaks. The program was reviewed for completeness and accuracy and to determine modifications that need to be made in order to include the West Service Zone. Following are our findings and recommendations: 1. Based on information provided by the Water Department, the formulas and spreadsheet operations employed to determine water consumed in the Low and High Service Zones were found to be correct. However, the spreadsheet does not account for water which is supplied from the High Service Zone to the West Service Zone and water which backflows from the distribution system into the Airlite plant. It is recommended that the spreadsheet be modified to account for is these flow streams. 00 5 r 2. In order to include the West Service Zone into the current Night Rate Analysis program, it is recommended that the Night Rate Analysis Spreadsheet be modified to include the following: a. Calculation of water supplied to the West Service Zone from the Airlite plant. b. Calculation of water supplied to the West Service Zone from the Lyle Avenue booster station. c. Calculation of water volume changes in the Alfl Lane overhead tank. SUMMARY OF RECOMMENDATIONS Following is a summary of our recommendations: 1. Unavoidable underground water loss be included in Elgin's water accountability calculations, using IDNR's standards. 2. Information on water used under the "Irrigation," "Construction," and "Pool," categories be included in the data provided to the Water Department monthly by the Finance Department. 3. Water use summaries produced by the utility billing software be manually verified before being used for water accountability calculations. 4. Finance Department make water consumption adjustment information available to the Water Department monthly and the "City Manager's Operating Summary" report spreadsheet,which is used to calculate water accountability,be modified to So account for these adjustments. 5. The Water Production Spreadsheet be modified to account for waste streams identified at the Riverside plant. 6. Water used for surface wash at the Riverside plant be deducted when calculating water supplied to the Low Service Zone since it is withdrawn after the Low Service Zone effluent meter. 7. A meter be installed on the 6" non-potable water main through which backflow is occurring at the Airlite plant to permit deduction for future water accountability. 6 p r 8. The accuracy of the influent and effluent meters at the Riverside and Airlite plants be verified at least once a year, as a policy. 9. The just ended Water Department AMR Quality Review program be undertaken at some level periodically in order to ensure the integrity of the AMR system. 10. After all accounts have been converted to the AMR system, monthly water use data to be utilized for water accountability calculations be generated by the Water Department,utilizing data directly from the AMR system. 11. Adjustment be made for service meter errors for water accountability purposes. The City's water accountability would improve from the current 80%to about 87%when the above listed waste streams,unavoidable underground leakage and water used under the irrigation, construction and pool categories are taken into account. Additional improvement would be realized when service meter errors are accounted-for in the calculations. The chapters following present a more detailed discussion of the issues mentioned in this summary and the basis of our findings and recommendations. L IP L 0 0 L • 7 0 r CHAPTER II CITY OF ELGIN WATER SUPPLY SYSTEM The City of Elgin's water supply system consists of two (2)Water Treatment Plants,two (2)booster pumping stations, four(4) elevated tanks, six (6)reservoirs, and approximately 308 miles of water transmission and distribution mains. In 1996, the system supplied water to approximately 85,000 persons through 25,000 accounts, 18,000 of which utilize Badger's Telephone In-bound Automatic Meter Reading(AMR)technology. The system will be supplying water to a projected population of about 100,000 by year 2010. The various components of the system are described briefly in the following sections. WATER TREATMENT FACILITIES Potable water supplied to the City of Elgin is treated at the Riverside and Airlite Water Treatment Plants. The two plants have a combined capacity of 24 MGD. The Riverside plant obtains raw water from the Fox River and six (6) deep wells. The existing plant has a capacity of 16 MGD and was being expanded to 32 MGD at the time of this study. The plant supplies approximately 95%of the City's potable water. The Airlite Water Treatment Plant is located west of the Riverside plant and obtains raw water from five(5)deep wells. The plant has a nominal capacity of 8 MGD and supplies approximately 5%of the City's potable water. SLADE AND LYLE AVENUES BOOSTER STATIONS The Slade Avenue booster facilities receive treated water from the Riverside Water Treatment Plant and pumps it to the distribution system. The facilities include three 3.5 MGD booster pumps and three reservoirs with combined capacity of 4 MG. The Lyle Avenue booster station is an in-line facility which includes two 2.4 MGD in-line booster pumps. ELEVATED TANKS AND GROUND LEVEL STORAGE The Elgin water supply system includes four(4) elevated tanks with total combined capacity of 4.5 MG. The tanks are located at Shales Parkway,Randall Road, Alfi Lane and the Airlite plant. Water is also stored in six (6) ground level reservoirs located at Slade Avenue(3), Riverside Water Treatment Plant(1) and the Airlite Water Treatment Plant(2). The six (6) reservoirs have a combined capacity of 7 MG. 8 0 WATER DISTRIBUTION SYSTEM The water distribution system is divided into three service zones, namely, the Low, High, and West Service Zones. The service zones are demarcated based on the topography and geography of the City. The Low Zone receives its water supply from the Riverside Water Treatment Plant and the Slade Avenue booster facilities. This service zone includes the Shales Parkway elevated tank,the Riverside reservoir,the three Slade Avenue reservoirs and booster pumping station and the Riverside Water Treatment Plant. It is the largest of the three service zones. The High Service Zone receives its water supply from the Riverside and the Airlite Water Treatment Plants. It encompasses the Lyle Avenue booster pumping station; Airlite Water Treatment Plant, elevated tank and reservoirs (2); and the Randall Road elevated tank. This is the second largest service zone. The West Service Zone is the smallest of the three zones. It receives its water supply from the Airlite plant and the Riverside plant via the Lyle Avenue booster pumping station. This service zone includes the Alft Lane elevated tank. There were approximately 308 miles of water mains in the water distribution system as of the end of 1997. The pipes ranged in size form 2" to 30". About 32 percent of the water mains were installed between 1888 and 1940. Between 1940 and 1987, approximately 47 percent of the existing water mains were installed while the remaining 21 percent were installed during the last ten years. The Elgin water distribution system also has approximately 3,200 fire hydrants as of the end of 1997, 26 percent of which were installed before 1940. The majority of the hydrants (45 percent)were installed between 1940 and 1987. The remaining 29 percent were installed during the last ten years. • 9 L p �e< r CHAPTER III REVIEW AND EVALUATION OF EXISTING WATER ACCOUNTABILITY PROGRAM GENERAL Figure 1 illustrates the elements included in the City of Elgin's water accountability program. Water accountability is defined as the total water that is utilized for various purposes divided by total water produced during the same period. The calculations are performed by the Water Department utilizing data from the following sources: 1. Water Production Spreadsheet. This is a computer spreadsheet which tracks water from the source through pumping and storage facilities in order to determine net water supplied to the distribution system. The spreadsheet is maintained by the Water Department. 2. Consumption by Range report. The Consumption by Range report summarizes water measured through meters and for which a bill is generated. The report is prepared monthly by the Finance Department. 3. "Non-billed" water use report. This report summarizes water which is utilized for known purposes but for which no bill is generated. Most of this water is not metered. The report is prepared monthly by the Water Department. The Water Department utilizes data from the above three sources to determine total water accounted-for as a percentage of total water produced on a monthly basis. The results are reported as part of the monthly "City Manager Operating Summary" report. The accuracy of the calculated water accountability depends on the accuracy of water production and consumption data. The determination of water produced will be impacted by the accuracy of source flow measuring devices and careful consideration of all sources supplying water to the system. On the consumption side, the determination of water utilized will be impacted by the accuracy of service meters and methods utilized to estimate non-metered uses. Determination of accountability would be further impacted by data processing errors such as recording of inaccurate meter readings, inaccurate conversion of flow units and inaccurate posting of data. All of the above listed areas and related issues were reviewed in order to evaluate the adequacy of the City of Elgin's water accountability program. The objective of the review was to determine whether the program was complete in terms of the elements it should include and to verify the accuracy of the methodologies utilized to calculate water accountability. ro 10 p Irri II VII Mil PM WM PM PM MR PIM Will rtm mu PM 1.41 1!"111 ELEMENTS INCLUDED IN WATER ACCOUNTABILITY PROGRAM CITY OF ELGIN, ILLINOIS Total Production: River Intake Raw water meter readings from Riverside Wells Use Raw water meter readings from Riverside River Non—Bil ed A Airlite pumpage to High Pressure Zone —D►—.Metered -►--- Airlite pumpage to West Pressure Zone Consumptions LI Plant Use Non—Billed Metered Consumptions River Intake AMR Surface Wash Billed Metered ` Non—Potable Water Consumptions Billed Metered Consumptions: Total Residential Production/ '� Manual Commercial/Industrial V Bulk Water ri Calculated Non—Billed Non—Metered Consumptions Non—Billed Street cleaning Estimated •� Non—Metered —Pm-- Leaks Consumptions, 9 a Slade Ave. Reservoirs — Estimated H Estimated Hydrant flushings — Estimated V Hydrant leaks — Estimated Underground leaks — Estimated ■ Billed Fire fighting — Estimated Non—Metered --+► Calculated Consumptions Sludge — calculated Waste — Calculated Billed Non—Metered Consumptions: New Construction — Calculated BILLED METERED CONSUMPTIONS + BILLED NON—METERED CONSUMPTIONS + NON—BILLED METERED CONSUMPTIONS + NON—BILLED NON—METERED CONSUMPTIONS + WATER X 100 ACC OU%NTABILITY TOTAL PRODUCTION ALVORD, BURDICK & HOWSON m ENGINEERS 1998 CHICAGO a HISTORICAL WATER ACCOUNTABILITY The City of Elgin's accounted-for and unaccounted-for water for the period 1984 through 1997 are illustrated in Figure 2. The City's unaccounted-for water declined from approximately 32% of production in 1984 to approximately 16% in 1989, and remained at approximately 16% of production between 1989 and 1991. In 1992, there was a sharp increase to about 24%. This increase could not be explained from the available data but it was suggested by the Water Department that it could be due to a major leak which occurred for several months at the Casa Linda Apartment Complex. The unaccounted-for water declined from 24%in 1992 to about 17% in 1994 and then increased again to about 20% from 1994 to 1996. At the end of 1997, the unaccounted-for water had declined to about 19%. On the average, approximately 20%of the water produced from 1984 through 1997 was unaccounted-for. REVIEW OF SYSTEM UTILIZED TO DETERMINE MONTHLY WATER PRODUCTION As indicated earlier in this report,the accuracy of calculations for determining water supplied to a water distribution system would be impacted by the accuracy of source meters and methodologies utilized to account for water which is treated but not supplied to the distribution system for consumption. The review of Elgin's current practice for determining monthly water production involved reviewing performance of flow measuring devices at the Riverside and Airlite Water Treatment Plants, the Slade and Lyle Avenues booster facilities as well as the computer spreadsheet(Water Production Spreadsheet)which is used to calculate water supplied to the distribution system. A. Measurement of Water Produced at the Riverside Water Treatment Plant The Riverside plant obtains raw water from the Fox River and six (6) deep wells. The raw river water supply is measured by means of a 24" magnetic flow meter while the well water is measured by means of a 20" venturi meter. The plant's effluent is measured by means of a 16" venturi meter for High Service Zone supply and a 30" venturi meter for Low Service Zone supply. The Riverside influent and effluent meters were installed in 1982 and their testing history is summarized in Table 1. The river water meter was not calibrated during 6 of the last 11 years while the well water meter was not calibrated during 3 of the last 14 years. The High and Low Service Zone meters were not calibrated during five and two years,respectively, of the last twelve years. • is. Under the current practice of water accountability,water supplied to the High Service Zone from the Riverside plant is determined based on readings of the High Service Zone meter while water supplied to the Low Service Zone is calculated utilizing the Riverside influent meter readings, less in-plant water use and less water supplied to the High Service Zone. The Low Service Zone meter readings are used to verify Low Service Zone water supply calculations based on raw water supply, in-plant water use and water supplied to the High Service Zone. 11 WM FM FM PINI PM PM OM OM PM mil rag rpm rig rgmi ACCOUNTED-FOR AND UNACCOUNTED-FOR WATER CITY OF ELGIN, ILLINOIS 100 ACCOUNTED-FOR WATER 90 13 YEAR AVERAGE = 79.9 70 60 z c) 50 cr w a 40 UNACCOUNTED-FOR WATER 30 13 YEAR AVERAGE = 20.1% • 10 0 1984 1985 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996 1997 T C YEAR ALVORD, BURDICK & HOWSON m ENGINEERS 1998 CHICAGO IV r Table 1 Riverside Meters Testing History • River water influent 24" Well water influent 16" High Service Zone 16" Low Service Zone Magnetic meter Venturi meter Venturi meter 30"Venturi meter Year Tested Tested Tested Tested 1984 N/A YES N/A N/A 1985 N/A NO N/A N/A 1986 YES YES YES YES 1987 NO YES YES YES 1988 NO YES YES YES 1989 YES YES YES YES 1990 YES YES YES YES t1991 NO YES NO NO 1992 YES NO NO NO 1993 YES NO YES YES 1994 NO YES YES YES 1995 NO YES NO YES 1996 NO YES NO YES 1997 YES YES NO YES The accuracy of the Riverside plant meters will impact calculations of water accountability. Therefore, it is recommended that the accuracy of these meters be verified at least once a year, as a policy, to ensure accurate measurements. Water for in-plant use at the Riverside plant, i.e. non-potable water, surface wash and potable water, is measured by means of Badger's turbine service meters. These meters are not tested. However, all the current units were installed during the last three years. The accuracy of these meters would impact calculations of water supplied to the Low Service Zone under current practice of calculating water production at the Riverside plant. Therefore, it is recommended that these meters be tested periodically in order to ensure accurate measurements. r 6i • 12 Pi r B. Measurement of Water Produced at the Airlite Water Treatment Plant r The Airlite plant's influent and effluent are measured by means of 16" venturi flow meters. The accuracy of the influent meter was verified during six of the last nine years. The accuracy of the influent meter does not impact water accountability calculations under current practice since calculations of water production at the plant begin with the effluent meters. The Airlite plant's High and West Zone meters were installed in 1963 and calibrated at L. least once during five of the last nine years. Calculation of water supplied from the Airlite plant L. to the distribution system is determined from the readings of the two effluent meters. The accuracy of these meters will therefore impact the calculations of water accountability. As a policy, it is recommended that the accuracy of these meters be verified at least once a year rC. Measurement of Water supplied by the Slade and Lyle Avenues Booster Stations Some of the water which is treated at the Riverside plant is supplied to the Slade and Lyle Avenues booster stations which in turn pump the water to the Low and West Service Zones, respectively. Water supplied from the Slade Avenue booster station is measured by means of one 16" and one 18" venturi meters installed in 1992. The available data indicated that the two r meters were calibrated in 1993 and 1995. The Lyle Avenue booster station's discharge meter was calibrated in 1995 and 1997. It is recommended, that as a policy, these meters be calibrated at least once a year to ensure accurate measurements. D. Water Production Spreadsheet rThe Water Department utilizes a computer spreadsheet to calculate water supplied to each of the three service zones. The spreadsheet tracks water through the system based on daily meter r• readings;water level changes in elevated tanks,reservoirs and basins; and operating hours of sludge pumps at the Riverside plant. Monthly water production is calculated as the total net water supplied to the three service zones. ., The Water Production Spreadsheet was reviewed to verify the logic of the spreadsheet, accuracy of formulas utilized to perform calculations, and whether the spreadsheet includes all r areas of the system that will impact the determination of total net water supplied to the three service zones. r The spreadsheet was reviewed with the aid of the flow diagrams illustrated in Figures 3 th and 4. Figure 3 illustrates the flow diagram for the over-all Elgin water supply system while Figure 4 illustrates the flow diagram for the Riverside plant. A detailed flow diagram was required for the Riverside plant because calculations of water supplied to the system from the plant begin with the incoming raw water. At the Airlite plant,the calculations begin at the effluent meter. ... ill 13 66 w FLOW DIAGRAM OF WATER SUPPLY SYSTEM CITY OF ELGIN, ILLINOIS -►Residential Customers -i•Industrial Customers -►Commercial Customers Residential Customers —Street Cleaning Industrial Customers —41"-\-0.-Leaks Commercial Customers -so-Hydrant Flushings Street Cleaning -ow Bulk Water Leaks -0.-New Construction Hydrant Flushings a -so-Fire Fighting Bulk Water -IN-Barlett New Construction -0-Storage Fire Fighting Sleepy Hollow Storage f 1 U HIGH SERVICE WEST ZONE ZONE ❑ LOW SERVICE ZONE 11 Lyle Ave. Wooster RIVERSIDE WATER TREATMENT PLANT 116. ��� "� Slade Ave. r' J • Reservoirs e r--� pumps 0 • 1 1 • o AIRUTE —� 4, River Meter- WATER TREATMENT i Metered Flow Riverside b ; © Calculated Flow 0 Night Flow From Flve N., Distribution System XI Wells ALVORD. BURDICK & HOWSON rri ENGINEERS 1998 CHICAGO tN ril MS ern Vol PM Mill Wilt PM RPM PM PM PM NMI Mil PM rill emu rim rim FLOW DIAGRAM OF THE RIVERSIDE WATER TREATMENT PLANT CITY OF ELGIN, ILLINOIS Waste Flow Stream not Included in Current Accountability ©Calculated Flow CD Estimated Flow ® Metered Flow To High Service Zone To Low Service Zone r► A lb 1 - - ® ''� Potable r Non-Potable Water Water (NPW) Itr el Iii) v Surface AHU-2 Domestic Wash Water Water -0-- Waste i .. 1 --..„...---1 -J-.- Sludge -►- Waste Clear Well -+-0-111"- _ Well Water In-Plant RIVERSIDE WATER � Backwash - ►-� Chlorination Use TREATMENT PLANT AND PUMPING FACILITIES Waste Riverside�� Slade Ave. To Low Zone Reservoir Reservoirs --►--- & Pumps -i -Lawn Sprinkling ., --ow-Maintenance -.—Turbidimeters i_ I_ -o-Chlorine Residual Q,, c• - Analyzers 3 3 C .—i.►Sampling Taps - C T) ' m 3 ix ALVORD, BURDICK & HOWSON ENGINEERS 1998 CHICAGO 4h. r At the Riverside plant,the Water Production Spreadsheet tracks raw water pumpage, sludge pumped to waste,water stored in the clear wells and wash water recovery basin and readings of the High and Low Service Zone meters. At the Airlite plant, the spreadsheet tracks finished water supplied to the High and West Service Zones utilizing readings of the High and West Service Zone meters. The spreadsheet also tracks water stored in each reservoir and elevated tank in the system. The facilities included in the spreadsheet and the basis of calculating water supplied to or from the facilities are summarized as follows: Table 2 Facilities Included in the Water Production Spreadsheet Facility Determination Riverside plant raw water supply Readings of influent meters Riverside plant ground level reservoir storage Water level changes in reservoir Riverside plant clear well storage Water level changes in reservoir Riverside plant wash water recovery basin storage Water level changes in basin Riverside plant sludge pumped to waste Rated flow and operating hours of sludge pumps Riverside plant supply to High Zone High Zone meter readings Riverside plant supply to Low Zone Influent meter readings adjusted by in-plant use and High Zone supply Shales Parkway elevated tank storage Water level changes in tank Alft Lane elevated tank storage Water level changes in tank Slade Avenue reservoir storage Water level changes in reservoir Airlite elevated tank storage Water level changes in tank Randall Road elevated tank storage Water level changes in tank Airlite plant reservoir storage Water level changes in reservoir r Airlite plant supply to High Zone High Zone meter readings Airlite plant supply to West Zone West Zone meter readings Lyle Avenue booster pumpage Readings of discharge meter The methodologies employed to track water through the various facilities included in the Water Production Spreadsheet were found to be logical. The net water supplied from water supply facilities to the distribution system would be the total raw water treated adjusted for in- plant water use and for water which is supplied to (or from)water storage facilities. The existing City of Elgin's Water Production Spreadsheet is set up to perform these calculations. However, the spreadsheet was found to be missing a number of waste streams at the Riverside and Airlite plants (see Figures 3 and 4). At the Riverside plant,the spreadsheet is missing the following waste streams: 14 r 1. Water used to supply chlorine solution at 55 gpm to the five deep wells. This water is extracted after the effluent meters. Since this water goes back to the source it must be considered a loss and deducted from the effluent meter readings. The amount of water that would be lost through this source would depend on the operating hours of the deep wells. Based on data provided by the City, the deep wells operated for approximately 600 hours in 1997 which is equivalent to 1.98 MG of water loss. 2. Flows through 5 turbidimeters and 1 chlorine residual analyzer for water quality control. Based on information provided by the Water Department,water flows continuously at a rate of approximately 16,950 gpd for the turbidimeters and 720 gpd for the chlorine residual analyzer. This amounts to 6.45 MG of water loss annually. 3. Flows through plant sampling taps for water quality control. The sampling taps flow at approximately 642 gpd, or 0.23 MG per annum. Other waste streams identified at the Riverside plant which are not accounted for in the Water Production Spreadsheet included water used for maintenance and lawn sprinkling during the summer. However,based on discussions with staff of the Water Department, it was determined that water lost through these sources is insignificant. The Water Production Spreadsheet also does not account for water which is used for surface wash when calculating water supplied to the Low Service Zone from the Riverside plant. Even though this water is recycled, since it is withdrawn after the Low Service Zone effluent meter(see Figure 4), it should be deducted when calculating water supplied to the Low Service Zone. Approximately 4 MG of water were used for surface wash in 1997 based on Water Department records. A total of approximately 13 MG of water went to waste in 1997 through the waste streams identified at the Riverside plant. For future water accountability, it is recommended that the Water Production Spreadsheet be modified to account for the above listed waste streams. At the Airlite plant, the Water Production Spreadsheet does not account for water which backflows from the distribution system into the plant. The backflow occurs when the high service pumps at the plant are turned off. Water which backflows is repumped into the distribution system,thus being double counted. Based on data provided by the Water Department,the Airlite plant supplied approximately 8 MG more in finished water than it received in raw water supply in 1997. Based on water pumpage data provided by the Water Department,the Riverside plant supplied about 98 percent of its raw water to the distribution system in 1997 while 2%was used at the water plant. Assuming the Airlite plant has a similar ratio, from a total of 305.43 million 15 C gallons of raw water supplied to the Airlite plant in 1997, it would have supplied 299.32 million gallons of finished water to the distribution system. However, the record indicated that the plant supplied 313.60 million gallons of finished water to the system in 1997. Based on these calculations, 14.28 million gallons of water were double counted in 1997. Currently, there are no means available to measure water which backflows into the Airlite plant. To account for this water in future water accountability calculations, it is recommended that a meter be installed on the 6" non-potable water main through which the backflow is occurring so that the amount can be deducted. Normally,water supplied to the water distribution system is calculated based on readings of effluent meters at water treatment and pumping facilities. In-plant water use is then calculated as the difference between readings of the influent and effluent meters. Water supplied by the Airlite plant to the West and High Service Zones is calculated on this basis in the current Water Production Spreadsheet. For the Riverside plant,water supplied to the Low Service Zone is calculated based on readings of the influent meters less in-plant water use. While this method is theoretically correct, there could be difficulties to accurately account for all in-plant water use because some quantities included in the calculations would be estimates. Such in-plant water use as lawn sprinkling,vehicle washing, etc., though not very significant and not considered in the calculations,would impact the accuracy the calculations. For the purpose of calculating water accountability this potential source of inaccuracy could be eliminated if water supplied to the distribution system from the Riverside plant were calculated based on readings of the two effluent meters. The meter readings would have to be adjusted to account for water which is returned to the plant through connections after the effluent meters (potable, non-potable and surface wash water connections). The formulas utilized in the Water Production Spreadsheet to calculate water supplied to or from reservoirs and elevated tanks are based on dimensions of the structures. The water volume change in each structure is calculated as the product of water level change and the cross sectional area. For spherical shapes like the Alft Lane, Randall Road and Shales elevated tanks, volume change per water level change is calculated based on gaging tables provided by the tank manufacturers. r We have reviewed the formulas used to calculate water volume changes in reservoirs and elevated tanks for the Water Production Spreadsheet and the spreadsheet operations to calculate water production and have found them to be correct. REVIEW OF SYSTEM UTILIZED TO DETERMINE WATER USE Water use data is obtained from two reports, a "Consumption by Range" report,which summarizes monthly metered and bill-generating uses, and a "Non-billed water" report, which summarizes non-bill-generating uses. 16 r A. Metered and Bill-Generating Uses The majority of the water supplied to the Elgin water distribution system is consumed through 25,000 metered accounts. Meter reading data is processed by the Finance Department's computer to determine total monthly water use. A monthly summary of water used is prepared by the Finance Department as part of its "Consumption by Range" report. The water use data is then utilized by the Water Department to calculate water accountability. The water billing data processing system was reviewed in two steps. First, the system g p g Y was reviewed to ascertain if meter reading data was being correctly converted to water billing units. Second, the Finance Department's water use data was reviewed to verify that it is consistent with data being used by the Water Department for water accountability. The February 1998 data for the 500 route accounts,which represent the commercial and industrial accounts, and"Consumption by Range" reports for the twelve months of 1997 were used for the review. Following are our findings: 1. Meter reading data is reported to the Finance Department in cubic feet. For all the accounts which were reviewed, the conversion to water billing units of hundred cubic feet was correctly done. 2. There are discrepancies between "water consumption" data used by the Water Department to calculate water accountability and Finance Department data. For example, the "water consumption" figure used by the Water Department for February, 1997,water accountability was 384,283 hundred cubic feet; the Finance Department's figure for the same period was 388, 284 hundred cubic feet. Table 3 is a comparison of the two departments' figures for the 12 months of 1997. The Finance Department believes the discrepancies are due to consumption adjustments which are made after the "water consumption" data has been sent to the Water Department. On the average about 30 water consumption adjustments are made weekly. It is recommended that the Finance Department make consumption adjustment information available to the Water Department monthly and that the "City Manager's Operating Summary" report spreadsheet be modified to account for these adjustments. 17 r Table 3 Comparison of Finance and Water Departments' "Water Use" Data for 1997 Finance Department's Water Department's Month "Water Use" (100 ft3) "Water Use" (100 ft) January 373,312 374,003 February 388,284 384,283 March 371,498 371,910 r April 364,087 363,563 May 376,059 381,869 June 416,211 412,909 July 423,799 437,601 August 504,781 503,842 September 465,325 464,465 October 457,151 452,295 November 412,474 413,181 December 431,187 437,938 r r 3. Water consumed from the distribution system is billed under four categories, namely, Water, Irrigation, Pool, and Construction. "Water consumption" data, which the Finance Department provides to the Water Department monthly as part r of the "Consumption by Range" report and which is used to calculate water accountability, does not include water used under the "Irrigation," "Construction," and "Pool" categories. During the 12 months of 1997, approximately 43 MG of water were used under these three categories but not included in the calculation of water accountability. It is recommended that this information be provided to the Water Department monthly. F 4. There were discrepancies in the total monthly"water consumption" and "accounts billed" figures generated by the Finance Department computers and reported as part of the "Consumption by Range" report. For example, the data from the "Consumption by Range"report for the month of January 1997 is as follows: r r 18 r Total Consumption RangQ Consumption(100 ft3) Count 0 - 250 ft3 222,297 11,944 251 - 500 ft3 16,343 50 501 - 1,000 ft3 17,524 25 1,001 - 2,000 ft3 25,544 19 2,001 - 5,000 ft3 24,892 7 5,001 - 10,000 ft3 15,320 2 t 10,001 - 53.127 1 Total 373,312 12,139 In actuality,the totals when added manually are 375, 047 hundred cubic feet and 12,048,respectively. For the 12 months of data which was reviewed,the water consumption totals produced by the computer were consistently lower than the totals manually calculated. The data for the twelve months of 1997 is summarized in Table 4. The total "water use" figure reported in 1997 was approximately 18 MG lower than the total calculated manually. Table 4 Comparison of Computer Generated and Manually Added Consumption by Range Totals Computer Generated Manually Added rMonth Totals (100 ft3) Totals(100 ft3) January 373,312 375,047 February 388,284 390,049 March 371,498 373,083 April 364,087 367,384 May 376,059 378,778 June 416,211 417,292 July 423,799 426,044 August 504,781 506,150 September 465,325 468,283 October 457,151 458,340 November 412,474 414,538 December 431.187 433,179 4,984,168 5,008,167 The discrepancies for the 1997 data were less than 1% and may be due to the accuracy of the consumption by range utility program. The developers of the 19 E r program have indicated that they were aware of the problem and that it was being corrected in the upgraded version of the software. The information contained in the "Consumption by Range" reports serves as a basis for determining metered water uses which constitute the majority of water used from the distribution system. The accuracy of these reports will impact calculations of water accountability. The City will convert to an improved water billing system in 1998. Therefore, it would not be prudent to invest further in the current program. However,it is recommended that, in the meantime,consumption summaries produced by the utility billing software be manually verified before being used for water accountability calculations. About 18,000 of the 25,000 accounts in the Elgin water distribution system use the AMR system and therefore are read monthly. That information is now available at the Water Department. Once all accounts are converted to AMR, the Water Department will have monthly water use data for every account in the system. We would recommend that, at that point, water accountability calculations be based on monthly metered uses generated by the AMR system instead of the Finance Department's computers. When all accounts are converted to the AMR system, the Finance Department would continue to bill bimonthly. For water accountability, it would be unnecessary to use bimonthly data since actual monthly data would be available. Based on a City request, Badger has made provisions in the AMR system for easy retrieval of total monthly water use data. B. Non-Metered Use The water accountability calculations include estimates of"non-billed" water use. This category of water use includes water used for flushing new water mains, fire fighting and training of firemen,hydrant flushing,underground leaks, Slade Avenue reservoir leaks,hydrant leaks, bulk water(water supplied to tankers from hydrants) and river water. Except for river water, which is water supplied from the distribution system to the raw water pumps at the Riverside plant and which is measured by a meter,the estimation of water used through non-metered sources is based on the following standards which have been adopted by the Water Department: 1. Disinfection of new water mains Twice the volume of water main 2. Slade Avenue reservoir leakage 990,000 gallmon 3. Bulk water Volume of truck and metered measurements 4. Fire fighting and training of firemen1,000 gpm 5. Hydrant flushing 1,000 gpm 6. Underground leaks repaired Leakage rate calculated during repair x 30 days 7. Hydrant leaks repaired Leakage rate calculated during repair x 30 days 20 ita r The calculation of water used for new water main disinfection and flushing assumes a quantity that is twice the volume of the pipe. In our opinion, this assumption is reasonable because it takes into account water used for disinfection and flushing. Leakage from the Slade Avenue reservoirs represents water which leaks from reservoirs r No. 1 and No. 2. Leakages from the two reservoirs were calculated in 1993 and 1995 respectively. If it is not possible to repair these leaks, it is recommended that they be measured periodically to verify the accuracy of the leakage rates utilized in water accountability. The estimation of bulk water(truck volume measurement)would yield reasonably accurate results. However, truck operators are provided meters which they are supposed to use : , when filling their trucks. These meters are read once a year by the Water Department. Therefore,while monthly bulk water sales (truck volume measurements) are estimates, the water is accounted-for annually through actual meter readings. The City should continue to inspect bulk water loading stations periodically to ensure that the meters are being used. According to the Water Department, the Fire Department lets the staff of the Water Department know when water is utilized for fire fighting or training. The Water Department uses that information and the assumed flow rate of 1,000 gpm to estimate the water used. Hydrant flow rates would depend, among other things, on the size of main to which the hydrant is connected and system pressures. Therefore, flows are never constant for all hydrants in the distribution system. There are no practical means available to accurately estimate water used for fire fighting. Other municipalities use methods similar to Elgin's in estimating water used for fire fighting. However, the Illinois Department of Natural Resources allows only 1% rwater loss for fire fighting. The estimation of water used for hydrant flushing will also be impacted by the same considerations for estimating water used for fire fighting. In our opinion, since water used for hydrant flushing does not represent a significant amount, the current practice is reasonable. Hydrant and underground leaks are a universal problem in an established water distribution system such as Elgin's. Water lost through hydrant and underground leaks is currently estimated using actual leakage rates measured at the time of repair. However, it would be difficult to estimate how long an underground leak has existed. We are not aware of a system or methodology that would provide more accurate results. During a 1996 Pitometer Associates system-wide leak survey which was performed for the City of Elgin, 106 leaks were located. The leaks included hydrant, service and main leaks. r The total estimated water loss through these leaks was 489,500 gpd or 178.7 MG per year. This amounts to approximately 4%of water produced in 1996. Implementing a periodic leak detection program would help minimize underground leaks. L 21 r However, there are some leaks that are occurring under conditions that make it difficult, if not impossible, to be detected by sounding devices. To account for this loss, the Illinois Department of Natural Resources allows municipalities which are supplied Lake Michigan water to include in their water accountability calculations a category called "Maximum Unavoidable Leakage." The calculations of"Maximum Unavoidable Leakage" are based on the following IDNR standards: 1. Cast Iron Pipes With Lead Joints Pipe Age Leakage Rate p g g 60 years or older 3,000 g/d/mi 40 - 60 years old 2,500 g/d/mi 20 -40 years old 2,000 g/d/mi • 20 years or less 1,500 g/d/mi 2. All Other Types of Pipes and Joints Pipe Age Leakage Rate 60 years or older 2,500 g/d/mi 40- 60 years old 2,000 g/d/mi 20- 40 years old 1,500 g/d/mi 20 years or less 1,000 g/d/mi It is recommended that "Unavoidable Leakage" be included in Elgin's water accountability calculations and be calculated based on IDNR standard. Based on information provided by the Water Department, there were 308.3 miles of water P Y � mains in the Elgin water distribution system as of the end of 1997. The estimated ages of the water mains are as follow: Pipe Age Miles Percent 1. 60 years and older 35.0 11.4 2. 40 -60 years old 74.3 24.1 3. 20- 40 years 105.3 34.1 4. 20 years or less 93.7 30.4 308.3 100.0 It is recommended that unavoidable leakage for pipes 40 years and older(109.3 miles)be calculated using IDNR flow rates for cast iron pipes with lead joints. Unavoidable leakage for the rest of the water mains should be calculated using IDNR's "Other Types of Pipes and Joints" flow rates. Based on these assumptions, unavoidable leakage for the Elgin water distribution system would be approximately 542,400 gpd or 198 MG per year, calculated as follows: 22 r 1. 60 years and older 35.0 x 3,000= 105,000 gpd 2. 40 - 60 years old 74.3 x 2,500= 185,750 gpd 3. 20 - 40 years 20 years or less 105.3 x 1,500= 157,950 gpd 4. 93.7 x 1,000= 93,700 gpd Total 542,400 gpd C. Review of Meter Reading System Most of the water used in the City of Elgin's water distribution system is measured through 25,000 service meters, ranging in size from 5/8" to 10". About 72 percent of these meters utilize Badger's Telephone In-Bound ACCESSp1us Automatic Meter Reading (AMR) technology. The remaining 28 percent are read manually by Water Services, a private contractor. Meter reading data for the AMR accounts is collected monthly by the Meter Shop section of the Water Department,while data for the non-AMR accounts is collected bimonthly by Water Services. All accounts are billed bimonthly except for the industrial and commercial accounts which are billed monthly. Meters using the AMR system have been installed since 1990. During installation, each meter is programmed to "call-in" a meter reading to a control computer monthly. The meter readings are then transferred to the City's water billing computer located at the Finance Department for billing purposes. Prior to January 1998, only AMR data for residential accounts was transferred electronically to the Finance Department computers. Currently, AMR data for all accounts is transferred electronically. In 1997 the Water Department initiated a program to review the AMR accounts after it was discovered that the AMR system was reporting only 10 percent of water used by a commercial account. As a result of that review, the Department discovered the following: 1) Seven(7) large meters serving commercial/industrial accounts were programmed with incorrect pulse test circle. The meter pulse test circle is a function of meter size and determines whether flow is electronically reported in tens, hundreds or thousands of cubic feet. The pulse test circles for the 7 meters in question were incorrectly programmed to report water use in tens, instead of hundreds, of cubic feet. As a result, these meters were reporting only 10 percent of water being consumed. 2) Some 250 accounts were assigned duplicate meter serial numbers. Readings for these accounts were being rejected by the billing software and consumptions were determined based on estimates. p 23 • r 3) A limited number of meters were found to be recording inaccurate readings. The AMR review program has been completed and all meters identified with the above listed problems have either been reprogrammed or replaced. We have reviewed the City's meter installation procedures and have independently obtained similar instructions from Badger. The City's meter installation procedures were found to be in conformance with Badger's instructions. Based on information provided by the Water Department, the initial instructions furnished by Badger for the installation of the AMR meters did not cover the larger meters,which contributed to some of the AMR problems. About two years ago,the Water Department developed a set of procedures which should help minimize the occurrence of meter installation errors. These procedures require, among other things, that each time a meter is installed, the meter installer verifies that the mechanical and electronic readings agree before leaving the premise. discussed above point to the potential for future errors in the AMR system. The problems discu p p Y Therefore, it is recommended that the just ended Water Department AMR Quality Review Program be undertaken periodically at some level to ensure the integrity of the AMR system. D. Accounting for Meter Errors The determination of total metered water use will be impacted by the accuracy of service meters. For water accountability purposes, the AWWA recommends that adjustments be made to raw meter readings to account for service meter errors. Under the current water accountability practice,the City of Elgin does not account for service meter inaccuracies. As a policy, service meters are tested only when requested by the customer and the results of the tests are not applied to water accountability calculations. In order to more accurately determine metered water use for water accountability, it is recommended that service meter errors be accounted for. The AWWA recommends two adjustment factors, one for residential meters and another for commercial and industrial meters. The adjustment factor for residential meters should be determined by randomly sampling 50 to 100 meters, including new meters and meters removed from service. Adjustment factor for large meters serving commercial and industrial facilities should be determined by testing all meters in that category. Because commercial and industrial accounts normally use a high percentage of water supplied to the distribution system, errors in the large meters could significantly impact !! water accountability. Procedures of determining adjustment factors for residential and commercial/industrial meters are outlined in "Water Audits and Leak Detection" (AWWA M36), published by the AWWA. iso r S 24 I I E. Adjusting for Meter Reading Lag Time Under the current Elgin water accountability practice,water production calculations are performed daily and totalled for each month. However, except for the commercial and industrial accounts which are billed monthly, all accounts are billed bimonthly. Moreover, all meters are not read on the same date. Therefore, the monthly "water consumption" data used for water accountability does not have the same time base as the water production data. Theoretically,the calculations should balance out since "under billing" during one billing cycle should result in "over billing" in a subsequent cycle. This is why annualized water accountability figures are a better gage than monthly figures. However,the City may want to consider performing more detailed annual water audits in which January and December's use would be adjusted to reflect the actual water used during the twelve months of the year. That figure should then be compared to the total water produced that year. This adjustment is not made under the current 12 month running water accountability calculations. Since all meters utilizing the AMR system report a monthly consumption, these calculations should be easier to perform once all accounts are converted to the AMR system. SUMMARY AND CONCLUSIONS The City of Elgin's water accountability program was evaluated for completeness and accuracy. We reviewed the Water Production Spreadsheet which is used to track water from the source through pumping and storage facilities in order to determine net water supplied to the water distribution system, and the "Consumption by Range" reports,which give monthly summaries of water used. We also reviewed the meter reading data processing system,meter testing program and methodologies employed to estimate non-metered water uses. In g eneral, Elgin's water accountability program was found to be well thought out. The sophistication of the computer spreadsheets utilized to track water through the water system and to perform water accountability calculations indicate that much thought and effort was put into developing the program. Our study has found no inadequacies in the logic of the program. However, a number of modifications are recommended in order to more fully account for the water which is being produced and accounted-for. These modifications include accounting more fully for waste streams at the Riverside and Airlite Water Treatment Plants,manually verifying consumption summaries produced by the Finance Department computers, accounting for unavoidable underground leaks and service meter errors, and verifying the accuracy of all source meters at least once a year. ii 25 0 r CHAPTER IV REVIEW AND EXPANSION OF THE NIGHT RATE ANALYSIS PROGRAM C INTRODUCTION The Minimum Night Rate Analysis program is part of the Water Department's program that tracks water used from the distribution system on a 24 hour basis. The Minimum Night Rate Analysis program tracks water use between the hours of 2:00 A.M. and 4:00 A.M. on Sundays when water use is assumed to be at a minimum. Results of the program are used to detect any unusually high water demands which may be due to leaks. Currently, the program tracks water use in the High and Low Service Zones. The objectives of this review were to verify that the program is complete, in terms of the elements which it should include, and to modify it for use in the West Service Zone. REVIEW OF EXISTING MINIMUM NIGHT RATE ANALYSIS PROGRAM The current Minimum Night Rate Analysis program consists of a computer spreadsheet which is used to track water supplied to the Low and High Service Zones. The elements included in the program and the basis of tracking water use are summarized in Table 5. Table 5 Facilities Included in Current Minimum Night Rate Analysis Spreadsheet Facility Included in Program Determination Shales elevated tank Water level changes in tank Airlite Street elevated tank Water level changes in tank Randall Road elevated tank Water level changes in tank Riverside Low Zone supply Pumpage rate of Riverside Low Zone pumps Riverside High Zone supply Pumpage rate of Riverside High Zone pumps Slade Ave. Low Zone supply Pumpage rate of high lift pumps Airlite Low Zone supply Pumpage rate of Low Zone pumps An attendant at the Riverside plant keeps track of pumping operations in order to determine the OP correct hourly pumpage rates. When pumping operation change occurs between hours, the ist average pumpage rate is utilized for that time period. We have reviewed the existing Night Rate Analysis Spreadsheet and following are our findings and recommendations: A! 26 r 1. The calculation of water used in the Low Service Zone was found to be correct. Water used in the Low Service Zone would be the total water supplied from the Riverside plant and the Slade Avenue booster facilities plus the net water volume change in the Shales elevated tank. The spreadsheet was set up to perform these calculations and therefore no modifications are required. 2. The calculation of water supplied to the High Service Zone does not account for water which is supplied from the High Service Zone to the West Service Zone via the Lyle Avenue booster facilities. It is recommended that the spreadsheet be modified to account for this water. 3. The calculation of water supplied to the High Service Zone from the Airlite plant does not account for water which backflows from the distribution system into the Airlite plant(see "Water Production Spreadsheet" in Chapter III). It is recommended that the spreadsheet be modified to account for this flow stream using readings of the proposed meter(see Figure 3 in Chapter III). Since information transmitted from the Airlite plant to the Riverside control room is limited, the rate at which this flow is occurring will not be available on an hourly basis when the meter is installed. Therefore, an average flow rate,based on a number of measurements,be used. 4. The formulas utilized to calculate water supplied to and from elevated tanks were found to be correct based on information provided by the Water Department. Therefore,no modifications are required. 5. Spreadsheet operations utilized to calculate hourly water use in the High and Low Service Zones were found to be correct. Therefore, no modifications are required. 6. The time for recording the Night Rate Analysis data, i.e. 2:00 A.M. to 4:00 A.M., seems reasonable. Low flows for most water utilities occur during this time period. The Water Department could verify that this time is suitable by periodically analyzing its hourly water use data. No changes are recommended. EXPANDED MINIMUM NIGHT RATE ANALYSIS PROGRAM In order to include the West Service Zone into the Minimum Night Rate Analysis PIP Spreadsheet,provisions would have to be made to account for the following: 1. Water supplied from the Lyle Avenue booster station to the West Service Zone. The Lyle Avenue booster station does not have a flow rate indicator at the Riverside control room where the hourly data is recorded. Therefore, an estimated flow rate of 2.3 MGD is currently being used to calculate hourly flows. 27 The booster pumps were installed in 1992 and rated at 2.4 MGD. These s um p p are relatively new and should be operating near design conditions(depending on system hydraulics). Therefore, a 2.3 MGD flow rate appears to an acceptable estimate. However,we would recommend that, if it is possible, some flow measurements be performed in order to verify the assumed flow rate. 2. Water supplied to the West Service Zone from the Airlite p lant. 3. Water storage volume changes in the Alft Lane elevated tank. SUMMARY AND CONCLUSIONS The current Night Rate Analysis program was reviewed for completeness and accuracy. Based on information provided by the Water Department, the formulas and spreadsheet operations employed to determine water used in the Low and High Service Zones were found to be correct. However, the spreadsheet does not account for water which is supplied from the High Service Zone to the West Service Zone and water which backflows from the distribution system into the Airlite plant. It is recommended that the Minimum Night Rate Analysis Spreadsheet be modified to account for these flow streams. In order to include the West Zone into the current Night Rate program,� Analysis Y p �' ,the following provisions would have to be made in the spreadsheet: 1. Calculation of water supply pp y to the West Service Zone from the Airlite plant. 2. Calculation of water supply to the West Service Zone from the Lyle Avenue booster station. 3. Calculation of water volume changes in the Alft Lane elevated tank. It is recommended that the above listed modifications be made to the current Night Rate Analysis Spreadsheet in order to include the West Service Zone. re 28 Po