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Exhibit MSD 65B - 2005 CDM Wet Weather Flow Cost Allocation Study1 1 1 7 Metropolitan St. Louis Sewer District Wet Weather Flow Cost Allocation study January 2005 � Final Report 1 MSD PN 04-092 CDM PN 20314-43486 1 Contents ISection 1- Introduction 1.1 Background 1-1 I 1.2 Scope of Services and Project Approach 1-2 1.2.1 Background Investigation and Data Collections 1-2 1.2.2 Development of Alternative Allocation Methodologies 1-3 1 1.2.3 Preferred Alternative Development 1-3 1.2.4 Preliminary Report 1-3 1.2.5 Project Completion and Final Report 1-3 1 1.3 Report Organization 1-3 Section 2 - Data Development 1 2.1 Data Collection Summary 2-1 2.1.1 Impervious Area by Customer Class 2-1 1 2.1.2 Inch -Feet of Pipe 2-2 2.2 Wet Weather Flow Analysis 2-2 2.2.1 Wastewater Treatment Plant Analysis 2-2 1 2.3 Data Analysis Limitations 2-7 - 2.4 Sanitary Sewer Overflow Estimates 2-7 Conclusions 2-9 12.5 Section 3 - Wet Weather Volume Cost Allocation Alternatives 1 3.1 Introduction 3-1 3.2 Existing Rate Model Sensitivity Analysis and Wet Weather Cost Allocation Alternatives 3-2 1 3.2.1 Existing Rate Model Sensitivity Analysis 3-3 3.2.2 Sensitivity Analysis Results 3-5 3.3 Factors Used to Develop Wet Weather Cost Allocation Alternatives 3-13 1 3.3.1 Updated Percentages of Wet Weather Volume to Wastewater Volume 3-13 3.3.2 Alternative Capacity and Volume Cost Allocation Methodologies 3-14 3.4 Wet Weather Cost Allocation Alternatives 3-15 1 3.5 Wet Weather Cost Allocation Alternative Evaluations 3-18 3.5.1 Existing Rate Model -Baseline Analysis 3-18 3.5.2 Alternative 2 - 8-Inch-Foot Equivalent Capacity Allocation 3-25 1 3.5.3 Alternative 3 - Capacity Allocation Base on 50-Foot/ 6-Inch Lateral 3-32 3.6 Conclusion 3-39 CDM P 120314 MSOt43486 bl Cost Allocation StudykFlnal Repon1TOC doct Table of Contents Preferred Alternative Report t t i i 1 1 Section 4 - Allocation Alternative Comparison 4.1 Introduction 4-1 4.2 Revaluation Criteria and Ranking Methodology 4-2 4.2.1 Rate Impact 4-2 4.2.2 Ratemaking Methodology 4-3 4.2.3 Class Equity 4-3 4.2.4 Administrative Simplicity 4-6 4.3 Summary of Criteria Ranking 4-7 Appendix A Wet Weather Flow Analysis Technical Memorandum Appendix B Billing Summaries Appendix C Evaluation Matrix Calculations Appendix D Glossary CDPA 1 P:1203t4 MSDW3488 1.1 Cosi Aaocation StudyPnal Report1TOCReport.doct Table of Contents Preferred Alternative Report I Figures 1 1 1 1 1 1 1 2-1 2001-2003 Rainfall at Wastewater Treatment Plants vs. Lambert St. Louis International Airport 2-4 2-2 Dry Weather Flow vs. Wet Weather Flow Percentage by Service Area 2-5 3-1 MSD Wet Weather Cost Allocation Percent Change From Baseline 3-4 P.120314 MSDt434B61.1 Cost Atloeadon StuoyFinat ReoonlTOC.00ct Table of Contents Preferred Alternative Report Tables 1 2-1 Impervious Area By Customer Class 2-1 2-2 Length and Equivalent Length of Separate Area and Combined Area ISewer 2-2 2-3 Wastewater Treatment Plant Wet Weather Analysis Results 2001-2003 2-3 2-4 Wet Weather Analysis Results for Service Areas Analyzed from 2001-2003 2-5 I 2-5 Percent Wet Weather Volume in System 2-6 2-6 Average Annual Volume in Combined Service Areas Z-6 I 2-7 Average Annual Volume in Separate Service Areas 2-7 3-1 MSA Wet Weather Cost Allocation & Rates Status Quo (Base Line) 3-6 3-2 MSD Wet Weather Cost Allocation & Rates Status Quo I(Base Line) Rate Comparison 3-7 3-3 Alternative B - MSD Wet Weather Cost Allocation & Rates Distribution of Estimated Wet Weather Flows to Capacity and Volume -100 Percent of Wet Weather Costs Allocated by Volume Comparative Revenues 3-8 3-4 Alternative B - MSD Wet Weather Cost Allocation & Rates Distribution of I Estimated Wet Weather Flows to Capacity and Volume 100 Percent of Wet _ Weather Costs Allocated by Volume Comparative Rates 3-9 3-5 Alternative C - MSD Wet Weather Cost Allocation & Rates Distribution of 1 Estimated Wet Weather Flows to Capacity and Volume 100 Percent of Wet Weather Costs Allocated by Customer/Capacity Comparative Revenues 3-10 1 3-6 Alternative C - MSD Wet Weather Cost Allocation & Rates Distribution of Estimated Wet Weather Flows to Capacity and Volume 100 Percent of Wet 1 Weather Costs Allocated by Customer/Capacity Comparative Rates 3-11 3-7 Alternative D - MSD Wet Weather Cost Allocation & Rates 50/50 Split of Wet Weather Costs to Customer/Capacity and Volume Comparative 11 Revenues 3-12 3-8 Alternative D - MSD Wet Weather Cost Allocation & Rates Distribution of Estimated Wet Weather Flows to Capacity and Volume 50/50 Split Wet 1 Weather Costs to Customer/Capacity and Volume Comparative Rates 3-13 3-9 MSD Wet Weather Cost Allocation & Rates Update Estimated Wet 1 Weather Flow Percentage Calculation of Weighted Average by Service Area 3-14 3-10 Alternative 1(a) - MSD Wet Weather Cost Allocation & Rates Update I Estimated Wet Weather Flow Percentage Comparative Revenue 3-19 3-11 Alternative 1(a) - MSD Wet Weather Cost Allocation & Rates Update Estimated Wet Weather Flow Percentage Comparative Rates 3-20 1 3-12 MSD Wet Weather Cost Allocation & Rates Distribution of Estimated Wet Weather Flows to Capacity and Volume Impervious Area by 1 Customer Class 3-21 C it, i P:120314 MSD143486 I -I Cost Allocation StudtAFinal Report TOC.Oocs Table of Contents Preferred Alternative Report 3-13 Alternative 1(b) - MSD Wet Weather Cost Allocation of Rates Wet Weather Capacity Allocated by Customer - Volume by Impervious Area Comparative Revenue 3-22 3-14 Alternative 1(b) - MSD Wet Weather Cost Allocation & Rates Wet Weather Capacity Allocated by Customer - Volume by Impervious Area Comparative Rates 3-23 3-15 Alternative 1(c) - MSD Wet Weather Cost Allocation & Rates Wet Weather Volume & Subsidized Stormwater Costs Distributed by Impervious Area Comparative Revenue 3-24 3-16 Alternative 1(c) - MSD Wet Weather Cost Allocation & Rates Wet Weather Volume & Subsidized Stormwater Costs Distributed by Impervious Area Comparative Rates 3-25 3-17 Alternative 2(a) - MSD Wet Weather Cost Allocation & Rates Distribution of Estimated Wet Weather Volume to Capacity and Volume Capacity Based on 8-Inch-feet of System Pipe 3-26 3-18 Alternative 2(a) - MSD Wet Weather Cost Allocation & Rates Distribution of Estimated Wet Weather Flows to Capacity and Volume Capacity Based on Minimum 8-Inch-feet of System Pipe Comparative Revenues 3-27 3-19 Alternative 2(a) - MSD Wet Weather Cost Allocation & Rates Distribution of Estimated Wet Weather Flows to Capacity and Volume Capacity Based on Minimum 8-Inch-feet of System Pipe Comparative Rates 3-28 3-20 Alternative 2(b) - Capacity Based on Minimum 8-Inch-feet of System Pipe Wet Weather Capacity Allocated by Customer - Volume by Impervious Area Comparative Revenues 3-29 3-21 Alternative 2(b) - Capacity Based on Minimum 8-Inch-feet of System Pipe Wet Weather Capacity Allocated by Customer - Volume by Impervious Area Comparative Rates 3-30 3-22 Alternative 2.3(c) - MSD Wet Weather Cost Allocation & Rates Wet Weather Volume & Unfunded Stormwater Costs Distributed by Impervious Area, 8-Inch-foot Pipe Allocation Comparative Revenue 3-31 3-23 Alternative 2.3(d) - MSD Wet Weather Cost Allocation & Rates Wet Weather Volume & Unfunded Stormwater Costs Distributed by Impervious Area, Impervious Area Rate Comparison Comparative Rates 3-32 3-24 Alternative 3 - MSD Wet Weather Cost Allocation & Rates Distribution of Estimated Wet Weather Flows to Capacity and Volume Capacity Based on 50-Feet of 6-Inch Diameter Laterals 3-33 3-25 Alternative 3(a) - MSD Wet Weather Cost Allocation & Rates Distribution of Estimated Wet Weather Flows to Capacity and Volume Capacity Based on 50-Feet of 6-Inch Diameter Laterals Comparative Revenues 3-34 3-26 Alternative 3(a) - MSD Wet Weather Cost Allocation & Rates Distribution of Estimated Wet Weather Flows to Capacity and Volume Capacity Based on 50-Feet of 6-Inch Diameter Laterals Comparative Rates 3-35 CEIM V P:120314 MS131434881.1 Cost Allocation Study Final RepontTCC.aoct 1 i t i t t i i i 1 Table of Contents Preferred Alternative Report 3-27 Alternative 3(b) - Capacity Based on 50-Feet of 6-Inch Width Laterals Comparative Wet Weather Capacity Allocated by Customer - Volume by Impervious Area Revenue Comparison 3-36 3-28 Alternative 3(b) - Capacity Based on 50-Feet of 6-Inch Width Laterals Comparative Wet Weather Capacity Allocated by Customer - Volume by Impervious Area Comparative Rates 3-37 3-29 Alternative 3(c) - MSD Wet Weather Cost Allocation & Rates Wet Weather Volume & Unfunded Stormwater Costs Distributed by Impervious Area 8-Inch-foot Pipe Allocation Comparative Revenue 3-38 3-30 Alternative 3(c) - MSD Wet Weather Cost Allocation & Rates Wet Weather Volume & Unfunded Stormwater Costs Distributed by Impervious Area Impervious Area Rate Comparison 3-39 4.1 Rate Impact Changes to Single Family Bill Standard Deviation and Evaluation Score 4-2 4-2 Inter -Class Equity Changes to Customer Class Costs Standard Deviation and Evaluation Score 4-4 4-3 Intra-Class Equity Changes to Customer Class Billings Standard Deviation and Evaluation Score 46 4-4 Class Equity Evaluation Score Summary 4-6 4-5 Existing Rate Structure and Alternative 1, 37/63 Percent Capacity/Volume Allocation Wastewater Allocation Alternative Evaluation Matrix 4-8 4-6 Alternative 2 Minimum 8-Inch-Feet of System Pipe - Wastewater Allocation Alternative Evaluation Matrix 4-9 4-7 Alternative 2 Minimum 8-Inch-Feet of System Pipe - Capacity/Volume Allocation Wastewater Allocation Alternative Evaluation Matrix 4-10 4-8 Summary of Weighted Alternatives 4-11 COM vi 1 P:120314 MSD43488 I-1 Cost Allocation Stu0y\Flnal RepornTOCRepon.tloq Section 1 Introduction 1.1 Background The Metropolitan St. Louis Sewer District (MSD) MSD is organized pursuant to Article VI, Section 30 of the state constitution, which empowers the people of St. Louis County and the city of St. Louis "to establish a metropolitan district for functional administration of services common to the area." MSD was created in 1954 to provide a metropolitan -wide sewer system and in 1956 MSD assumed operations of all publicly owned wastewater and storm drainage facilities within its originally established service area. This area is commonly referred to as the original area, including the incorporated area of the City. In 1977, MSD annexed a 279 square mile area of the lower Missouri River basin and the Meramec watershed, doubling its service area, and in 1978 purchased the Fee Fee Trunk Sewer Company and Missouri Bottoms Sewer Company. MSD has continued to expand its service area since 1978, purchasing several smaller wastewater systems and expanding services into St. Louis County based on requests for service by residents and currently services 524 square miles with a population of 1.4 million. MSD is a publicly owned and non-profit district which is supported by taxes and various charges levied on persons within its boundaries. MSD's Board of Trustees was given the authority to levee taxes and charges, in accordance with state laws and regulations to pay for the services provided by MSD. In November 2000, the voting public of St. Louis County and City created the Rate Commission by approving admendments to the MSD's Charter. The Rate Commission was established to provide a review of MSD rate change proposals and provide recommendations concerning these rate changes to the Board of Trustees. The Rate Commission is a group of 15 commissioners representing various ratepayer constituencies throughout the St. Louis Metropolitan Area. Although the commissioners are appointed by the MSD's Board of Trustees, the Rate Commission is defined by Charter as having independent and objective review responsible for all Rate Changes under consideration by MSD. The Rate Commission established governing procedures and guidelines for their deliberations which are outlined in the "Operational Rules, Regulations and Procedures of the Rate Commission." MSD submitted its first Rate Change proposal to the Rate Commission in May 2002 and revisions to the proposal in April 2003. The Rate Commission issued its rate recommendation in the Rate Commission Report (May 2003). In this report the Rate Commission recommended MSD conduct a study to determine the most accurate allocation and cost recovery method for Infiltration/Inflow (I/I) operation costs, and requested that the results be presented to the Rate Commission before any future rate change submittals. 1-1 P:120314 MS1143086 FI Cost Allocation Study,Final Repott\Secliontfinalcloc Section 1 Introduction MSD issued a request for Proposal (RFP) June 24, 2004, and selected CDM to perform the requested study. The study will address the six issues discussed in the Rate Commission's review. These issues are: 1. Wet Weather Flow; 2. Customer Classification; 3. Stormwater Cost Recovery; 4. Changes in Excess Strength Suspended Solids; 5. Additional Working Capital Requirements; and, 6. Resistance Factor 1.2 Scope of Services and Project Approach In 1993, MSD changed the Inflow/Infiltration (I/I) cost allocation from a 50/50 percent allocation to a 37 percent recovery by the system availability charge and 63 percent by volume recovery charge. There where no studies performed to substantiate the rationale for the change. The scope of this study is to investigate and present I/I cost allocation options, and assess advantages and disadvantages of each option with the goal of determining an acceptable methodology. Evaluations of the alternatives were based on criteria established in the Rate Commission Charter for rate reviews. Alternatives considered the development of rationales for customer and volume cost distribution, including impervious area and customer classifications, such as residential, commercial and industrial. The study was conducted in a series of work phases as described below. 1.2.1 Background Investigation and Data Collections Data and information needs were determined and collected from MSD. Information used in the evaluation and determination of alternative cost allocation methodologies included: • Daily flow data for each MSD wastewater treatment plant; • Rainfall data from MSD rain gauges; • Flow monitoring data from within the collection system; • Impervious area data for all service areas: • Collection system data, such as pipe length and diameter, for the entire collection system; 1-2 P:12031.4 MSD1434661.1 Cost allocation StudyTFinal RepontSecoonlynal doc 1 1 1 1 1 1 1 1 1 1 1 1 1 i 1 1 1 i COM 1 Section 1 Introduction ■ Number of accounts in the billing system; • Billed volume or number of billable units for all accounts; • Significant industrial user data; and, ■ Influent wastewater strength data at all MSD wastewater treatment plants. In addition, a review of industry standards and approaches implemented by other agencies similar to MSD were reviewed to establish wet weather cost allocation alternatives. 1.2.2 Development of Alternative Allocation Methodologies Alternative approaches for allocation I/I and wet weather costs were developed and screened. A cost -causative basis was used to recommend alternatives for further consideration. A workshop was held with MSD to review the findings and discuss system data and approaches recommended for determining the wet weather allocation percentages. 1.2.3 Preferred Alternative Development The alternatives recommended for evaluation were reviewed in more detail. A simplified rate evaluation model was developed and tested against the MSD rate model for accuracy as a tool to evaluate the revenue and cost impacts of each alternative. A Preferred Alternative Report was developed and distributed to the project team. A second workshop was conducted to review the results of the preferred alternative development and refine the evaluation matrix approach. 1.2.4 Preliminary Report A Preliminary Wet Weather Allocation Report was prepared and distributed to the project team members. The report focused on the development, analysis and rate and revenue changes of each alternative. The draft evaluation matrix and ranking criteria was included in the report. A final workshop was conducted with MSD at which time the preliminary findings of the study were presented and final comments from management were gathered. 1.2.5 Project Completion and Final Report Final revisions to the Wet Weather Allocation report were incorporated and the final Wet Weather Cost Allocation Report distributed to the project team. Final comments were received and changes made to the report as appropriate. Information contained in the final report includes a summary of the support data collected, the wet weather flow analyses, discussion of the alternatives, the evaluation matrix, and ranking of the alternatives. 1.3 Report Organization The report has been organized to present the data collected, its use in the development of the study, the resulting analyses; the development of alternative P:120314 MSD 434881.1 Cost Allocation Study\Final ReponU^ectionlliinal.doc 1-3 Section 1 Introduction methodologies and their associated impacts, and an evaluation matrix based on defined criterion and analyses results. The information contained in the report sections and appendices is outlined below: • Section 1 contains background information on MSD and the Rate Commission, and discusses the scope and activities conducted for the project. • Section 2 summarizes the data collected for the study, reviews the methodology and presents results of the wet weather flow analysis. • Section 3 defines each alternative evaluated and details the impact of the rate changes on customer classes. ■ Section 4 presents the evaluation matrix and recommended alternative. • Section 5 addresses the following additional issues requested by the Rate Commission: stormwater cost recovery, resistance factor, change in extra strength suspended solids, and working capital. • Appendix A contains an analysis of wet weather flow in five sewersheds. ■ Appendix B contains billing summaries for each alternative. ■ Appendix C contains the evaluation matrix calculations. ■ Appendix D contains a Glossary of terms used in the report. CDM 1-4 1 P: 20310 MS0413486 I -I Cost Allocation SludytFinal RepottlSectionffinal.doe 1 i i Section 2 Data Development 2.1 Data Collection Summary Data was collected from MSD to develop the alternatives described in Section 3. Additional analyses that were conducted to assist in data evaluations are contained in Appendix A. The data collected was used to: • calculate impervious area by customer class; • calculate the length of sanitary and combined sewer pipe in all service areas; • determine percentage of wastewater treated and wet weather flow volume for each wastewater treatment plant and combined area; • estimate annual volume of combined sewer overflows; and • estimate volume of wet weather flow transported bythe collection system. y 1 1 1 t t 1 CDM 2.1.1 Impervious Area by Customer Class Impervious area data and land use data for St. Louis City and St. Louis County was provided by MSD in SHAPE' file format and entered into a Geographical Information System (GIS) database. The impervious area square footage and percentages by customer class for the billable area are presented in Table 2-1. It is generally accepted that there is a correlation between stormwater runoff due to impervious area and wet weather flow. This data was used in Section 3 to calculate wet weather volume costs based on impervious area. * Table 2-1 Impervious Customer Class Impervious Area Square Feet Percent of Total Customer Class Impervious Area* Commercial 855,071,716 34.2% Industrial 314,116,495 12.6% Single Family Residential 1,111,065,766 44.4% Multi -Family Residential 220,046,834 8.8% Total* 2,500,300,011 100% i SHAPE files are files that contain a set of points,arcs, or polygons that hold tabular data and a spatial location. 2-1 P:120314 MSDW94881.1 Cost Nlocation Study'F,nal RepomSecUon2final.doc 1 1 1 1 a 1 i Section 2 Data Development Table 2-4 Wet Weather Analysis Results for Service Areas Analyzed from 2001- Average Annual Contribution Service Area Plant Inflow Volume (MG) Wet Weather Volume (MG) Wet Weather Flow Percentage (%) 16.6% Coldwater Creek 9728 1615 Missouri River' 10176 771 7.6% Lower Meramec 11615 1585 13.6% Bissell Point 44685 6075 13.6% River Des Peres 40416 9307 23.0% Total District 115902 19353 16.7% es: 1. Does not include October 2001 flow data Figure 2-2 Dry Weather Flow vs. Wet Weather Flow Percentage by Service Area 100% — - 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% --92% ----83% 8% 86%0 14% -- Coldwater Missouri Lower Creek River* Meramec 86% _ In Dry Wet Wet 77% 14% Bissell Point River Des Peres 'Does not include October 2001 flow data 2-5 t P:120314 MSD.434861.1 Cost Allocation SludylFlnal RepotltSeclion2finaltloc t i i 1 1 COM Section 2 Data Development The highest percent wet weather flow was seen in the River Des Peres Service Area at 23 percent. This percentage is probably low for a combined area such as River Des Peres because this percentage does not include contribution from combined sewer overflows (CSOs). Coldwater Creek also had a high percent wet weather flow at 17 percent. Since Coldwater Creek Service Area is a separate sewer system, this percentage indicates that this area is particularly susceptible to wet weather flow especially considering that sanitary sewer overflows (SSOs) are excluded from this analysis. CSO contribution was added to the total district averages presented in Table 2-4. An estimate of annual CSO contribution was included in the MSD Capital Improvements and Replacement Plan Report (SKME, 2002) for Bissell Point Service Area (9.3 billion gallons [BG]) and River Des Peres Service Area (16.7 BG) resulting in an annual CSO contribution of 26.6 BG. The values shown below in Table 2-5 combine this CSO contribution estimate with wastewater treatment plant analysis data presented in Table 2-4, to calculate the average annual district -wide wet weather contribution of 32 percent. Table 2-5 2001-2003 Percent Wet W Average Annual Wet Weather Volume at Treatment Plants 19353 MG Average Annual Total Volume at Treatment Plants 116,602 MG Average Annual Combined Sewer Overflow Contribution 26000 MG Average Annual Wet Weather Volume in System (CSO + Wet Weather Volume at Treatment Plants) 45353 MG Average Annual Total Volume in System (CSO + Total Volume at Treatment Plants) 142620 MG Percent Wet Weather Volume in System 32 percent In the combined service areas, the resulting annual percent wet weather volume when CSOs are considered is 29 percent in the Bissell Point Service Area and 45 percent in the River Des Peres Service Area. The combined annual wet weather contribution for the two combined sewer areas is 37 percent as shown in Table 2-6, and the combined annual wet weather contribution for the three separate service areas are in Table 2-7. Table 2-6 2001-2003 Avera Service Area Average Annual Contribution Plant Inflow Volume (MG) CSO Volume (MG) Total Volume in Combined Service Area - Plant Inflow + CSO (MG) Wet Weather Volume at Plant (MG) Total Wet Weather Volume - Wet Weather at Plant + CSO (MG) Bissell 44685 9300 53985 6075 15375 RDP 40416 16700 57116 3907 26007 Total Combined Sewer Areas 85101 26000 110383 15382 41382 Percent Wet Weather Flow 37% 2-6 P:t20314 MSDt434861.1 Cost Allocat,on StoOyiFinal ReporOSection26nal.00c i Section 2 Data Development i i t Table 2-7 2001-2003 Average Annual V Average Annual Contribution Service Area Plant Inflow Volume (MG) Wet Weather Volume (MG) Coldwater Creek 9728 1615 Missouri River' 10176 771 Lower Meramec 11615 1585 Total Separate Service Areas 31519 3971 Percent Wet Weather Flow 13% 1. Does not include October 2001 flow data In the separate service area, the percent wet weather flow could be higher than 13 percent due to the exclusion of SSOs. However, the CSO estimates assume that all CSO flow will be captured which could be a conservative estimate and may account for the unknown SSOs. The system wide wet -weather flow contribution is estimated as approximately 32 percent, and can be applied for a district -wide rate allocation. However, wet weather flow contribution varies between sewersheds, combined and separate sewer service areas, and due to the actual amount of CSOs and SSOs that will be captured for conveyance/storage and treatment. 1 2.3 Data Analysis Limitations t i i i i The analysis was focused at the wastewater treatment plant level using daily plant influent data, which provided estimates of service area level wet -weather contributions. This information is sufficient to evaluate and screen various wet weather rate evaluation alternatives. Other limitations include: • SSOs have not been modeled and would increase the wet weather flow percentage, especially in areas with many bypasses. MSD's sewer models could be used to simulate annual SSO volumes. This task could be undertaken to further refine the wet -weather volumes. • CSO volumes are derived from past analyses for River Des Peres and Bissell Point Service Areas. The analyses could be further refined with additional information describing actual CSO capture for treatment. 2.4 Sanitary Sewer Overflow Estimates Sanitary sewer overflows (SSO) occur in sanitary sewer systems dedicated to the collection and conveyance of wastewater; and do not combine wastewater with stormwater. SSOs occur in collection systems for several reasons including blockage, broken pipes, defects that allow stormwater or groundwater to enter the system, illicit connection of roof drains and sump pumps, inadequate operation and maintenance, equipment and power failures and vandalism. 2-7 P:t2O3l4 MSD43488 I•I Cost Allocation SludytFinal ReportSealon2tinat doe Section 2 Data Development MSD's separate collection system contains approximately 320 SSOs. The cost to monitor and measure sanitary sewer overflows (SSO) in a system with approximately 320 SSO locations would be expensive and difficult to maintain. The typical cost per meter day for in -pipe flow monitoring equipment is approximately $100 and for one year, the estimated cost to install, maintain and collect data for the flow monitoring equipment in each SSO would be $7 to $12 million. Two approaches have been used to estimate the impact SSO volume could have on the percentage of wet weather flow compared to wastewater flow collected in MSD systems. • Review of EPA estimates of the total volume of SSO attributed to municipal wastewater collection systems. • Analysis of how sensitive the percent of wet weather flow to wastewater flow is to the SSO volume estimate. EPA Report To Congress: Impact and Control of CSOs and SSOs In the EPA Report to Congress: Impacts and Control of CSOs and SSOs (published August 26, 2004) it was determined that there are about 19,000 municipal sanitary sewer collection system in the United States, discharging between 3 to 10 billion gallons of wastewater through SSOs. EPA has estimated that 74 percent of the SSO volume is related to wet weather, inflow and infiltration, and the remaining attributable to blockages and failures in the collection system. The report estimates the annual volume of treated wastewater, CSO and SSO. Based on this data and using a SSO estimate of 10 billion gallons per year, SSOs accounted for less than 1 percent of average volume discharged in a year, nationwide. The data contained in this report supports an increase of the system wide wet -weather flow contribution from 32 percent to 33 percent. Estimate Based on Inflow and Infiltration Per Foot of Lateral An estimate of the annual inflow that occurs per foot of private laterals was developed to test the impact inflow and infiltration could have on the wet weather volume conveyed by the collection system. This analysis did not attempt to determine the percentage of the flow entering the lateral that was treated; rather, assumed all the flow entering the system from laterals was discharged through SSOs and the wet weather flow treated by the treatment plants was due to inflow and infiltration occurring in the collection system. If an assumption of 5 to 20 cubic feet per foot per year of lateral is used to estimate the amount of wet weather volume entering the system (375 to 7480-gallons per year per typical home with a 50-foot lateral) and assuming 330,420 customer accounts in the separate collection systems identified in Table 2-4 (It is assumed that the separate collection systems include 100 percent of the accounts in Meramec, Coldwater Creek and Missouri River Service Area, 55 percent of accounts in Bissell Point Service Area, and 64 percent of accounts in River Des Peres Service Area, as identified in the Long Term Control Plan.), a total 2-8 i P:120314 MSDA43486 I -I Cost Allocation Studylf Ina! ReportsSection26nal clot Section 2 Data Development 1 i 1 1 t volume of between 620 and 2480 million gallons will be discharged through SSOs. Including this volume in Table 2-5, would support increasing the percent wet weather from 32.3 percent to between 32.3 and 33.1 percent. 2.5 Conclusions The following conclusions from these analyses can be used for the rate option evaluation: • Within the service areas, the wet weather flow contribution varied from 13 percent in the separate area systems to 37 percent in the combined area systems; and, • The system wide wet -weather flow contribution is estimated as approximately 33 percent and includes an estimate of the volume contributed by SSOs. These analyses demonstrate that wet weather contribution is variable between each service area. It is important to consider this when evaluating wet weather flow for sewer rates. A detailed flow monitoring data analysis and modeling program for wet weather conditions would be necessary to get an accurate account of wet weather flows and SSOs from separate service areas. 2-9 P120314 MS01434661.1 Cost Allocation Stuo7/,final Repon5Section26nal.00c i i 1 1 1 1 1 1 1 1 1 1 1 1 CIDM 1 Section 3 Wet Weather Volume Cost Allocation Alternatives 3.1 Introduction MSD currently maintains a model to update and evaluate its wastewater rates. This rate model has multiple modules linked together to produce rates and charges for the current fiscal year and forecasted periods. These modules consist of three essential components of ratemaking: Revenue Requirement, Cost of Service Allocation and Rate Structure Development. This section of the study focuses on the cost allocation and rate structure modules of the rate model. More specifically, how cost of service is allocated to I/I (wet weather) flows and how MSD rates are designed to recover those costs from customers. There are two primary factors that affect the wet weather cost allocation in the existing MSD rate model. These are: 1. The estimated percentage of wet weather flow to wastewater flow transported by the collection system; and 2. The distribution of wet weather flows to either capacity or volume charges in the cost of service allocation. MSD's current rate model distributes wet weather costs based on a 45/55 percent estimate of wet weather flow to wastewater flow and a 37/63 percent split between capacity and volume, respectively. Changing these primary factors in the rate model will redistribute the costs for wet weather volume to the established customer classes. For example, if the estimated percent of wet weather is reduced to 40 percent, this would increase the amount of costs allocated to the wastewater component of the rate base, increasing the total costs allocated to the customer class with larger contributed volume. Thus, all other things being equal, an increase in wet weather will decrease the charges to large volume customers and increase rates for smaller volume customers. Likewise a change to the wet weather volume distributed to capacity or changing distribution of volume cost from billed volume to impervious area would result in an increase in allocation to customers with larger contributed volumes or impervious areas. Presented in this section are the alternatives identified for allocating costs to customers using these primary factors, as well as several allocation methods for wet weather volume costs. These alternatives will be evaluated and compared to the P:120314 MSD143486 I -I Cost Allocation Stuoy.Final RepontSection3tinal.Coc 3-1 Section 3 Wet Weather Volume Cost Allocation Alternatives current costs allocated to the established customer classes for wastewater services. The primary tasks of this section are to: 1. Update the estimated percentage of wet weather flow to wastewater flow transported by the collection system based on the analysis conducted in Section 2; 2. Establish the basis for distribution of capacity and volume in the MSD rate model; and 3. Identify and evaluate alternate cost allocation methodology for wet weather volume costs. The results of each of the alternatives will be presented with customer impacts. This information is used to evaluate the alternatives in Section 4. 3.2 Existing Rate Model Sensitivity Analysis and Wet Weather Cost Allocation Alternatives The Financing and Charges for Wastewater Systems Manual (1984) prepared by the American Public Works Association, American Society of Civil Engineers, and Water Pollution Control Federation (presently WEF) indicates that the preferred method of allocation is to identify all points of flow entry and pass the cost of transporting and treating these flows onto the various classes of customers identified as the cost causers. Absent the ability to accurately identify the points of flow entry, the costs should be passed onto all customers, both in relation to the customer's flows and the total number of customers. Accordingly, MSD's rate model allocates the cost between the customer's capacity function and the volume function. What follows herein is a presentation of the alternatives evaluated as part of this study that are in accordance with generally accepted ratemaking practices. The - alternatives are divided into two groups. The first group is designed to illustrate the sensitivity of MSD's wastewater rate to changes in the "Existing Rate Model Results" (status quo/baseline). The Existing Rate Model Results are determined using the existing cost allocation methodology and rate structure. The second group of alternatives has been developed to address the two primary factors used to distribute wet weather costs to customers in MSD's rate model (Section 3.1). Each of the Alternatives 1 through 3 in the second group has a supportable engineering and economic basis, as well as compliance with generally accepted ratemaking practices. 3-2 P930314 MSD\434661-1 Cos, AIloolioo Slndy.Final Rcpal`ScaiadPool doc 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 COM 1 Section 3 Wet Weather Volume Cost Allocation Alternatives 3.2.1 Existing Rate Model Sensitivity Analysis This first group includes the Existing Rate Model results and three baseline alternatives. The three alternatives represent the range of impacts that a change in the allocation of wet weather costs between capacity and volume will have on wastewater rates. These alternatives were only developed to demonstrate MSD's wastewater rate sensitivity to changing cost allocations applicable to wet weather costs. This first group of alternatives will neither be ranked nor considered in the criteria ranking matrix included in Section 4. When changing the wet weather flows as it relates to the distribution of costs to capacity or volume, an increase in allocation to capacity (and decrease to volume) results in a decreased charge to customers (individual) with larger contributed volumes and an increase to customers with smaller volumes. Logically, a decrease in capacity will result in an increase in charges to customers with larger volumes. Several alternatives have been developed in this section that are designed to demonstrate the range of rate changes that result when allocating all wet weather costs to either capacity or volume. These alternatives assume that at one end of the range of rate changes, all wet weather costs will be allocated by distributing 100 percent of the cost to the volume function. In this alternative, all the wet weather costs will be recovered from customers through the volume charge component of MSD's current rate structure. This alternative produces significant increases to large volume customers while the small user is likely to realize a reduction in wastewater charges. At the other end of the range is the allocation of all wet weather costs 100 percent to customer/capacity. In this alternative, the wet weather costs will be recovered from customers using the System Availability component of MSD's current rate structure. It assumes that all wet weather costs are related to customers equally regardless of the size or the demands of the customer. This has a significant impact on the smaller volume user, increasing their rates. In addition to these two alternatives a third alternative is presented that allocates wet weather costs 50/50 between capacity and volume. This alternative was provided to present the impacts of changes to the existing 37/63 allocation factors. The alternatives in this first group that make up the sensitivity analysis are identified as follows: A. Existing Rate Model - Status Quo/Baseline • Ratio of wet weather flows to all wastewater flows is 45 percent • Allocation of wet weather costs to capacity and volume functions is 37/63, respectively P: 20314 MSD143486 1.1 Cost Allocation StudlnFinal Repon\$ection36nal.tloo 3-3 Section 3 Wet Weather Volume Cost Allocation Alternatives B. 100 Percent Volume • Allocation of all wet weather costs assuming 100 percent volume • Wet weather cost will be recovered from customers using the volume rate. • Assumes that all wet weather costs are related to customers based on their billable volume. C. 100 Percent Capacity • Allocation of wet weather costs assuming 100 percent capacity function • Wet weather cost will be recovered from customers using the System Availability rate component • Assumes that all wet weather costs are related to customers equally regardless of the size or the demands of the customer. D. 50/50 Allocation Capacity/Volume • Allocation of wet weather costs 50 percent to the volume function and 50 percent to the capacity function. The detailed results of each of these alternatives will be presented in Section 3.3. However, as a general overview the range of increases and decreases determined through this sensitivity analysis is displayed in Figure 3-1 below. 30.0% 20.0°/D 10.0% 0.0% -10.0% - -20.0% -30.0% -40.0% Figure 3-1 MSD Wet Weather Cost Allocation Percent Change from Baseline 100% Volume 100°/ :Cape city 50/5 d Volume/Capacity ci Single family ❑ Multi Family ❑ Non residential 3-4 P:\20314 MSD\434861.1 Cost Allocation Stody+Final Rcpocaoctionllinal.doc Section 3 Wet Weather Volume Cost Allocation Alternatives 3.2.2 Sensitivity Analysis Results CDM prepared a simplified version of MSD's rate model to test the results and impacts of each alternative. During the sensitivity analysis, the alternative assumptions were developed using this simplified model and compared to MSD's Existing Rate Model Results. The findings were presented in Figure 3-1. This graph displays a range of increases and decreases each customer class would experience if the wet weather cost allocation was shifted from 100 percent volume to 100 percent capacity. The figure illustrates that changing the existing allocation factor from the existing 37/63 to 100 percent volume and 0 percent capacity would increase the large volume/non-residential customer rates about 17 percent and decrease residential rates by about 16 percent. On the other hand, changing the existing allocation factor to 0 percent volume and 100 percent capacity will create a 29 percent decrease in non- residential rates and a 27 percent increase in residential rates. Since 100 percent is the most MSD can allocate to either volume or capacity functions, this defines the maximum range of the impact of the increases and decreases in rates on the various customer classes that can be expected from changing the wet weather cost allocation factors. The initial results of the simplified model were compared to MSD's rate model runs using the same alternative assumptions. This test was used to confirm the accuracy of CDM's model. The following is the detailed results of CDM's of the simplified model runs for the alternatives designed to prepare the sensitivity analysis. In addition, due to the inclusion of stormwater costs within the wastewater rates, the wastewater costs were analyzed separately by excluding the stormwater costs from the analysis. Therefore, the initial results of the simplified model are also presented with a column that excludes the stormwater costs. A. Existing Rate Model Results The alternative Existing Rate Model Results (A) is based on existing rates. Table 3-1 below provides the results of the base line alternative model run. It compares the revenue expected to be recovered from existing rates with the alternative results. There is also a comparison of the revenue per customer class that excludes the stormwater costs. 3-5 P\20374 MSDt43486 I-t Cost Allocation Study \Final RepoOSect,on3fnat.doc Section 3 Wet Weather Volume Cost Allocation Alternatives 1 1 1 1 1 1 1 1 i Table 3-1 Alternative A MSD Wet Weather Cost Allocation & Rates Status Quo (Base Line) Factors Utilized Ill Allocation 45% Capacity 37% Volume 63% Revenue Comparison Existing Cost of Service Revision Percent Change Revision Without Stormwater Costs Percent Change Metered Customers Single Family $72,704,600 $72,704,762 0% $66,953,667 -7.9% Multifamily 19,269,000 19,269,008 0% 17,800,744 -7.6% Non -Residential: Anheuser-Busch 7,566,700 7,566,724 0% 7,216,749 -4.6% All Other 59,601,100 59,600,938 0% 55,636,143 -6.7% Total $159,141,400 $159,141,432 $147,607,303 UnMetered Customers - Single Family $16,871,000 $16,870,981 0% $15,545,875 -7.9% ' Multi Family 10,327,500 10,327,489 0% 9,529,124 -7.7% Total $27,198,500 $27,198,470 $25,074,999 Total System Single Family $89,575,600 $89,575,743 0% $82,499,542 -7.9% Multifamily 29,596,500 29,596,498 0% 27,329,868 -7.7% Non -Residential 67,167,800 67,167,662 0% 62,852,893 -6.4% Total System $186,339,900 $186,339,902 _ $172,682,302 Since the existing rate revenue and alternative rate revenue is the same there is no change in the Percent Change column. However, for the alternative that excludes the stormwater costs, the percent change in revenue per customer class is presented. Table 3-2 presents the existing fee structure and rates, for with and without the stormwater costs. COM 3-6 1 P:@O314 MSD,134861•I Cost Allocuio,, StudyWinal Rcpor1Scciion)Ina1 dot Section 3 Wet Weather Volume Cost Allocation Alternatives 1 1 i 1 i i t 1 1 COM Table 3-2 Alternative A MSD Wet Weather Cost Allocation & Rates Status Quo (Base Line) Rate Comparison Ill Allocation 45% Capacity 37% Volume 63% Rate Comparison Existing Cost of Service Revision Percent Change Revision Without Stormwater Costs Percent Change Billing and Collection Charge/Bill $1.14 $1.14 0% $1.14 0% System Availability Chare/Silt $6.50 1 $6.50 0% $5.84 -10.0% Compliance Charge/Bill $11.35 $11.35 0% $11.35 0% Volume Charge $/Ccf $1.66 $1.66 0% $1.52 -8.6% Typical Residential Bill — 8 Ccf/Month $20.92 $20.92 0% $19.14 -8.6% B. Allocation Based on 100 Percent Volume Alternative B eliminates the allocation of wet weather flow costs to customer/capacity. It assumes all wet weather related costs should be recovered based on customer's billable volume. Table 3-3 provides the revenues derived from existing rates compared to estimated revenues determined using the allocation factors for this alternative. Table 3-3 also presents the revenues required per customer class with stormwater costs excluded. 3-7 i P:120314 MSD1434881.1 Cost Allocation StuoyiFinal RepontSection3final °oc Section 3 Wet Weather Volume Cost Allocation Alternatives s i t 1 i t 1 1 COM Table 3-3 Alternative B MSD Wet Weather Cost Allocation & Rates Distribution of Estimated Wet Weather Flows to Capacity and Volume 100 percent of Wet Weather Costs Allocated by Volume Comparative Reve Factors Utilized �VJ Ill Allocation 45% Capacity 0% Volume 100% Revenue Comparison Existing Cost of Service Revision Percent Change Revision Without Stormwater Costs Percent Change Metered Customers Single Family $72,704,600 $60,478,076 -16.8% $55,957,749 -23.0% Multifamily 19,269,000 21,831,140 13.3% 20,104,966 4.3% Non -Residential: Anheuser-Busch 7,566,700 8,700,341 15.0% 8,236,253 8.8% All Other 59,601,100 69,803,900 17.1% 64,812,049 8.7% Total $159,141,400 $160,813,457 $149,111,017 UnMetered Customers Single Family $16,871,000 $15,010,971 -11.0% $13,873,099 -17.8% Multi Family 10,327,500 10,515,474 1.8% 9,698,187 -6.1% Total $27,198,500 $25,526,446 $23,571,285 Total System Single Family $89,575,600 $75,489,047 -15.7% $69,830,848 -22.0% Multifamily 29,596,500 32,346,614 9.3% 29,803,153 0.7% Non -Residential 67,167,800 78,504,241 16.9% 73,048,301 8.8% Total System $186,339,900 $186,339,902 $172,682,302 This alternative creates significant shifts in revenue derived from various customer classes. The single family customers will see a sharp decrease while the non- residential customers will have an increase. With stormwater costs excluded, there is a greater decrease shown for single family customers and a smaller increase for non- residential customers. 3-8 i P:Q0314 MSD\34861.1 Cost Nloc ttion Study4Piml RcpmOScction3 final doc 1 Section 3 Wet Weather Volume Cost Allocation Alternatives 1 i 1 1 1 1 1 1 1 1 i 1 1 i Table 3-5 Alternative C MSD Wet Weather Cost Allocation & Rates Distribution of Estimated Wet Weather Flows to Capacity and Volume 100 Percent of Wet Weather Costs Allocated by Customer/Capacity Comparative Factors Utilized vvv Ill Allocation 45% Capacity 100% Volume 0% Revenue Comparison Existing Cost of Service Revision Percent Change Revision Without Stormwater Costs Percent Change Metered Customers Single Family $72,704,600 $93,523,140 28.6% $85,676,413 17.8% Multifamily 19,269,000 14,906,499 -22.6% 13,877,377 -28.0% Non -Residential: Anheuser-Busch 7,566,700 5,636,468 -25.5% 5,480,797 -27.6% All Other 59,601,100 42,228,329 -29.1% 40,012,306 -32.9% Total $159,141,400 $156,294,437 $145,046,892 UnMetered Customers Single Family $16,871,000 $20,038,039 18.8% $18,394,130 9.0% Multi Family 10,327,500 10,007,427 -3.1 9,241,280 -10.5% Total $27,198,500 $30,045,465 $27,635,410 Total System Single Family $89,575,600 $113,561,179 26.8% $104,070,542 16.2% Multifamily 29,596,500 24,913,926 -15.8% 23,118,657 -21.9% Non -Residential 67,167,800 47,864,798 -28.7% 45,493,103 -32.3% Total System $186,339,900 $186,339,902 $172,682,302 As one would expect, there is a swing in inequity the opposite of that found in Alternative 4. With this alternative, the single family will share the majority of the revenue increase, while the non-residential customer will have a significant decrease. The revenue requirement for single family decreases without the stormwater costs, decreasing the impact of a rate increase and the decrease in non-residential customer rates was greater. Table 3-6 presents the rate changes affected by this alternative. CDM 3-10 1 PV03l4 MSDA3486 Id Cost Allocation StudylFinal RcporOScction3final doc 1 Section 3 Wet Weather Volume Cost Allocation Alternatives J 1 1 1 1 a 1 1 1 1 i 1 1 1 COM Table 3-6 Alternative C MSD Wet Weather Cost Allocation & Rates Distribution of Estimated Wet Weather Flows to Capacity and Volume 100 percent of Wet Weather Costs Allocated by Customer/Capacity Comparati Factors Utilized v I/I Allocation 45% Capacity 100% Volume 0% Rate Comparison Existing Cost of Service Revision Percent Change Revision without Stormwater Costs Percent Change Billing and Collection Charge/Bill $1.14 $1.14 0% $1.14 0% System Availability Charge/Bill _ $6.50 $17.56 170% $15.80 143% Compliance Charge/Bill $11.35 $11.35 0% $11.35 0% Volume Charge $/Ccf $1.66 $0.96 -42% $0.91 -45.4% Typical Residential Bill -8 Ccf/Month $20.92 $26.38 26% $24.18 15.61% There is a significant increase in the System Availability Charge and a large decrease in the uniform volume rate. If this alternative were implemented, the typical customer could expect to see a 26 percent increase in monthly charges. D. Allocation Based on 50/50 Volume/Capacity Alternative D assumes all the wet weather costs will be recovered from customers using both the customer/capacity and volume rate equally. It assumes that wet weather costs are related equally to customers and the demands of the customer. Table 3-7 presents the revenue impact resulting from changing the estimated wet weather flow distributed by the 37/63 split to capacity and volume, respectively, to 50 percent customer/capacity and 50 percent volume. Table 3-7 also presents the revenues required per customer class with stormwater costs excluded. 3-11 1 P3203t4 MSD1434861.1 Cost Allocation SIudy\Flnal RepornSection36nal dcc 1 Section 3 Wet Weather Volume Cost Allocation Alternatives 1 1 1 1 i a 1 Table 3-7 Alternative D MSD Wet Weather Cost Allocation & Rates Distribution of Estimated Wet Weather Flows to Ca acit Factors Utilized Ill Allocation 45% Capacity 50% Volume 50% Revenue Comparison Existing Cost of Service Revision Percent Change Revision Without Stormwater Costs Percent Change Metered Customers Single Family $72,704,600 $77,000,606 5.9% $70,817,079 -2.6% Multifamily 19,269,000 18,368,814 -4.7% 16,991,166 -11.8% Non -Residential: Anheuser-Busch 7,566,700 7,168,408 -5.3% 6,858,528 -9.4% All Other 59,601,100 56,016,109 -6.0% 52,412,172 -12.1% Total $159,141,400 $158,553,938 $147,078,946 UnMetered Customers Single Family $16,871,000 $17,524,509 3.9% $16,133,618 -4.4% Multi Family 10,327,500 10,261,455 -0.6% 9,469,738 -8.3% Total $27,198,500 $27,785,964 $25,603,356 Total System Single Family $89,575,600 $94,525,116 5.5% $86,950,698 -2.9% Multifamily 29,596,500 28,630,269 -3.3% 26,460,904 -10.6% Non -Residential 67,167,800 63,184,518 -5.9% 59,270,701 -11.8% Total System $186,339,900 $186,339,902 $172,682,302 This alternative demonstrates that even a small change in the existing distribution of wet weather costs between capacity and volume can have a moderate affect on revenue derived from different classes of customers. Table 3-8 presents the rate changes affected by this alternative. COM 3-12 1 P:@0314 MSD 434S61.1 Cost Allocmion S1odyFinal RcporIScaion3Gnai doc Section 3 Wet Weather Volume Cost Allocation Alternatives i i i i t t Table 3-8 Alternative D MSD Wet Weather Cost Allocation & Rates Distribution of Estimated Wet Weather Flows to Capacity and Volume 50/50 Split Wet Weather Costs to Customer/Capacity and Volume Com arativ Factors Utilized I/I Allocation 45% Capacity 50% Volume 50% Rate Comparison Existing Cost of Service Revision Percent Change Revision without Stormwater Costs Percent Change Billing and Collection Charge/Bill $1.14 $1.14 0% $1.14 0% System Availability Charge/Bill $6.50 $8.78 36% $7.90 21.5% Compliance Charge/Bill $11.35 $11.35 0% $11.35 0% Volume Charge $/Ccf $1.66 $1.50 -10% $1.39 -16.17% Typical Residential Bill - 8 Ccf/Month $20.92 $21.64 5% $20.17 -3.58% 3.3 Factors Used to Develop Wet Weather Cost Allocation Alternatives Alternatives and updates to MSD's existing wet weather cost allocation methodology were identified and used to develop the second group of alternatives. These alternatives focus on the development of alternative methodologies for allocating costs in the capacity and volume ratemaking properties of the rate model. In all of these alternatives, (with the exception of the Existing Rate Model Status Quo Alternative), the percentage of wet weather flow to wastewater flow was updated to 33 percent based on the data and analysis presented in Section 2 and Appendix A. 3.3.1 Updated Percentages of Wet Weather Volume to Wastewater Volume The estimated percentage of wet weather flows, including CSO and SSO flow estimates (Section 2) were updated as part of this study. The updated percentage of wet weather flows is based on sampled actual flows to wastewater treatment facilities in all five of MSD's service areas. Table 3-9 displays the calculation of the updated wet weather flow percentage. This calculation is revised based on sampled data from MSD's wastewater facilities and the MSD Capital Improvement s and Replacement Plan Report (SKME 2002). 3-13 P120314 MSD143466 I -I Cost Mocation Slu°y'Final RepornSecti on30nri°°c Section 3 Wet Weather Volume Cost Allocation Alternatives t i i Table 3-9 MSD Wet Weather Cost Allocation & Rates Update Estimated Wet Weather Flow Percentage Calculation of Weighted Average by Service Area Average Annual CSO Total Wet Total Combination of Flow Volume Flow Weather % Wet Wet Weather (mg) (mg) (mg) Flow (mg) Weather Flow Coldwater Creek 9,728 9,728 1,615 16.6% 1.1% Missouri River 10,176 10,176 771 7.6% 0.5% Lower Meramec 11,615 11,615 1,585 13.6% 1.1% Bissell Point 44,685 9,300 53,985 15,375 28.9% 10.8% River Des Peres 40,416 16,700 57,116 26,007 45.5% 18.3% Total 116,620 26,000 142,620 45,353 32.0% 32.0% The 32 percent represents all wet weather flow weighted by service area including estimated CSO flows from combined areas. In consideration of SSO wet weather flow an estimated 1 percent was added, as discussed in Section 2.4 of this report. Although SSOs have not been monitored, it is generally accepted that there will be some wet weather flows that should be attributed to the SSO. All alternatives considered in the final analysis (Section 4), will use 33 percent to determine the ratio of wet weather flows to total system flows. 3.3.2 Alternative Capacity and Volume Cost Allocation Methodologies Several allocation methodologies have been identified for distribution of capacity and volume costs to each customer class. These alternatives have been used both individually and in combination to develop the Wet Weather Cost Allocation Alternatives. Descriptions of the allocation methodologies used to develop the capacity and volume cost allocation functions are described below. Capacity Allocations A. Allocation to capacity based on the existing rate model allocation percentage. The existing rate model allocates costs to the capacity function of the model based on a 37 percent allocation to capacity and 63 percent allocation to volume charge function of the rate model. B. Allocation to capacity by inch -foot length of pipe assuming 8 inch pipe is minimum capacity size for the system and is required to serve all customers. Since wet weather flow is related to inch -feet (or inch -mile) of collection system pipe, the distribution of costs to capacity will be based on the equivalent L'M 3-14 P:V0314 MSDW34$61.1 Cost Allocation Study,Final Rcpo,iScction3tna1 doc Section 3 Wet Weather Volume Cost Allocation Alternatives minimum 8-inch-foot pipe for the entire length of the systems. The volume allocation will be based on pipe diameter in excess of 8-inches. C. Allocation to capacity by lateral inch -foot length assumes 50-foot laterals for all customer connections and a 6-inch diameter. As with the previous alternative, since wet weather flow is related to inch -feet (or inch -mile) of collection system pipe, the distribution of capacity costs will be based on an estimate of the percentage of 50-foot, 6-inch diameter laterals for all customer connections divided by total system inch -foot length plus the inch -feet for laterals2. The percentage represented by the balance of the inch -foot length of the system will be used to allocate costs to volume. Volume Cost Allocation A. Billed Volume - distributes costs to the volume function of the rate model based on the uniform charge per Ccf for all billable volume. City accounts that are based on plumbing attributes have been included in the Ccf volume using unit volumes developed in the MSD rate study. B. Impervious area charge - This item was developed as an alternative to the rate structure currently used by MSD. This change adds a new rate component to the rate structure - charging the wet weather costs allocated to 3the volume - function based on the impervious area of the customer's property. Impervious area charges assume that the customer responsibility for wet weather costs is based on property use and impervious area. This rate methodology is a generally accepted fee structure for recovering storm water costs. This alternative recognizes that there is a correlation between storm water runoff and wet weather flows and passes the cost onto MSD customers accordingly. 3.4 Wet Weather Cost Allocation Alternatives The list of alternatives evaluated and ranked by CDM for this study is as follows: Alternative 1- Existing Rate Model - Baseline Analysis The existing rate model is used to distribute cost to each customer class based on the established methodology and percentage allocation between capacity and volume functions. These alternatives will provide a baseline to allow the reader to determine the changes in rates to each customer class using the existing capacity and volume function percentage. The changes to the model functions and cost centers used in each of Alternative 1 options are presented below: Inch -feet of pipe as used here means the pipe diameter selected of 8-inches times the linear feet of pipe in the system. 2 Lateral lengths are not recorded by MSD, thus the estimate of lateral length is added to the recorded pipe length provided by MSD for the study. A lateral is assumed to be equal to 300 inch -feet (50-foot length times 6-inch diameter). COM 3-15 P:120374 MSD 43a661.1 Cost Allocation StudytFinal Rep on%Sect,on3final doc Section 3 Wet Weather Volume Cost Allocation Alternatives Alternative 1(a) - Updated Estimated Wet Weather Volume Percentage • The ratio of wet weather flows to wastewater volume is updated to 33 percent; • Allocation of wet weather costs to capacity and volume functions is 37/63 percent, respectively; • Volume Costs are distributed to each customer class based billed on volume (Ccf). Alternative 1(b) - Volume by Impervious Area • The ratio of wet weather flows to wastewater volume is updated to 33 percent; • Allocation of wet weather costs to capacity and volume functions is 37/63 percent, respectively; • Volume Costs are recovered based on impervious area (square feet) of each customer class. Alternative 1(c) - Wet Weather Volume & Subsidized Stormwater Costs Distributed by Impervious Area • The ratio of wet weather flows to wastewater volume is updated to 33 percent; • Allocation of wet weather costs to capacity and volume functions is 37/63 percent, respectively; • Volume Costs are recovered based on impervious area (square feet) from each customers class; • Stormwater cost subsidized by wastewater rates are included in the volume costs and recovered based on impervious area of each customer class. Alternative 2 - Capacity Based on Minimum 8-Inch-Feet of System Pipe This alternative is based on 8-inch and smaller pipe established as the minimum capacity size for the system and is required to collect flow from all customers. Since wet weather flows is related to inch -feet (or inch -mile) of collection system pipe, the distribution to capacity will be based on the equivalent minimum 8-inch-foot pipe for the entire length of the system. The volume allocation will be based on pipe width in excess of 8-inch pipe. Alternative 2(a) - Capacity Based on Minimum 8 inch -feet of System Pipe Volume by Billed Volume • The ratio of wet weather flows to wastewater volume is updated to 33 percent; • Allocation of wet weather costs to capacity and volume functions based on 8-inch-feet of system pipe is 60/40 percent, respectively; 3-16 PA20714 MSDW3486 I -I Cost Nlocotion Stnd/8inal RcpomScctiooAfioot doc Section 3 Wet Weather Volume Cost Allocation Alternatives COM • Volume Costs are distributed to teach customer class based on billed volume. Alternative 2(b) - Capacity Based on Minimum 8 inch -feet of System Pipe, Volume by Impervious Area • The ratio of wet weather flows to wastewater volume is updated to 33 percent; • Allocation of wet weather costs to capacity and volume functions based on 8-inch-feet of system pipe is 60/40 percent, respectively; • Volume Costs are recovered based on impervious area of each customers class. Alternative 2(c) - Wet Weather Volume & Subsidized Stormwater Costs Distributed by Impervious Area • The ratio of wet weather flows to wastewater volume is updated to 33 percent; • Allocation of wet weather costs to capacity and volume functions based on 8-inch-feet of system pipe is 60/40 percent, respectively; • Volume Costs are recovered based on impervious area from each customers class; • Stormwater cost subsidized by wastewater rates are included in the volume costs and recovered based on impervious area of each customer class. Alternative 3 - Allocation to Capacity by Inch -foot Length of Pipe and Lateral Connection This alternative builds on the definition of the infrastructure required to serve all customers as discussed in Alternative 2 above, but is expanded to include laterals3 for all customer connection. As with the previous alternative, this alternative is based on defining the infrastructure required to collect flow from all customers. Wet weather flows is related to inch -feet (or inch -mile) of collection system pipe, the distribution of capacity costs will be based on an estimate percentage of 50-foot long, 6-inch laterals for all customer connections divided by total system inch -foot length plus the inch - foot for laterals4. The percentage represented by the balance of the inch -foot length of the system will be used to allocate costs to volume. Alternative 3(a) - Capacity Based on 50-Feet of 6-Inch Diameter Laterals • The ratio of wet weather flows to wastewater volume is updated to 33 percent; • Allocation of wet weather costs to capacity and volume functions based on 8-inch-feet of system pipe is 24/76 percent, respectively; ° It is CDM's understanding that laterals are not recorded by MSD: thus the estimate of laterals is added to the recorded pipe length provided by MSD for the study. 3-17 P:120314 MSDM34881 1 Cost Allocation Stud Final Repon5Sec1 on38nal doc Section 3 Wet Weather Volume Cost Allocation Alternatives 1 i t 1 1 i t t t i • Volume Costs are distributed to teach customer class based on billed volume. Alternative 3(b) - Capacity Based on Minimum 8-inch-feet of System Pipe, Volume by Impervious Area • The ratio of wet weather flows to wastewater volume is updated to 33 percent; • Allocation of wet weather costs to capacity and volume functions based on 8-inch-feet of system pipe is 24/76 percent, respectively; • Volume Costs are recovered based on impervious area of each customers class. Alternative 3(c) - Wet Weather Volume & Subsidized Stormwater Costs Distributed by Impervious Area • The ratio of wet weather flows to wastewater volume is updated to 33 percent; • Allocation of wet weather costs to capacity and volume functions based on 8-inch-feet of system pipe is 24/76 percent, respectively; • Volume Costs are recovered based on impervious area from each customers class; • Stormwater cost subsidized by wastewater rates are included in the volume costs and recovered based on impervious area of each customer class. The revenue distribution and rate for each customer class is evaluated for each of these alternatives in Section 3.5. These alternatives are further evaluated and ranked based on specific criteria which is presented in Section 4. 3.5 Wet Weather Cost Allocation Alternative Evaluations The simplified rate model developed for this study was completed; the CDM mock model was used to produce results from the second group of alternatives. These results were used as input in the final ranking matrix (Section 4). 3.5.1 Existing Rate Model - Baseline Analysis The detailed alternative analysis is as follows. Alternative 1(a) - Existing Rate Model - Update Estimate Wet Weather Volume This alternative updates the ratio of wet weather flow to total system flow from 45 percent to 33 percent as discussed in Section 3.2. Table 3-10 presents the revenue derived from each customer class using this update. This table displays the impact of the reduction from the existing 45 percent of flow applicable to wet weather flow to 33 percent. Table 3-10 also presents the revenues CDM 3-18 P.120314 MSDW3486 I.1 Cost Allocation Study Final RapofPScction3final dac 1 Section 3 Wet Weather Volume Cost Allocation Alternatives 1 1 1 i i 1 i required per customer class with stormwater costs excluded. In order to present the wastewater system costs separately, the column "Revision Without Stormwater Costs" does not include $13,657,602 in stormwater system costs. Table 3-10 Alternative 1(a) MSD Wet Weather Cost Allocation & Rates Updated Estimated Wet Weather Flow Percentage Compa Factors Utilized v v — Ill Allocation 33% Capacity 37% Volume 63% Revenue Comparison Existing Cost Of Service Revision Percent Change Revision Without Stormwater Costs Percent Change Metered Customers Single Family $72,704,600 $70,208,774 -3.4% $64,681,062 -11.0% Multifamily 19,269,000 19,742,623 2.5% 18,227,548 -5.4% Non -Residential: Anheuser-Busch 7,566,700 7,911,588 4.6% 7,540,902 -0.3% _ All Other 59,601,100 61,644,479 3.4% 57,493,275 -3.5% Total $159,141,400 $159,506,180 $147,942,787 UnMetered Customers Single Family $16,871,000 $16,482,964 -2.3% $15,191,840 -10.0% Multi Family 10,327,500 10,349,471 0.2% 9,547,671 -7.6% Total $27,198,500 $26,833,716 $24,739,511 Impervious Area Charges Single Family Multifamily Non -Residential: Anheuser-Busch All Other Total Total System Single Family $89,575,600 $86,691,738 -3.2% $79,872,902 -11.0% Multifamily 29,596,500 30,092,094 1.7% 27,775,219 -6.2% Non -Residential 59,601,100 61,644,479 3.4% 57,493,275 -3.5% Anheuser-Busch 7,566,700 7,911,588 Total System $186,339,900 $186,339,896 4.6% $172,682,298 -0.3% There is a slight shift of the revenue requirement from residential customers onto non- residential customers with this alternative. As the costs allocated to wet weather decline, more costs are allocated to the base wastewater volume rate. Larger volume customers carry the heavier burden of cost recovery in this wastewater rate structure. CDM 3-19 t P120314 MS01434861.1 Cost Allocation Sludy\Final Report \Seclion3rinal.doc 1 Section 3 Wet Weather Volume Cost Allocation Alternatives 1 1 1 1 1 1 1 1 1 1 1 Table 3-11 presents the rate changes affected by this alternative. Table 3-11 Alternative 1(a) MSD Wet Weather Cost Allocation & Rates Update Estimated Wet Weather Flow Percentage Comp Factors Utilized I/I Allocation 33% Capacity 37% Volume 63% Rate Comparison Existing Cost Of Service Revision Percent Change Revision without Stormwater Costs Percent Change Billing and Collection Charge/Bill $1.14 $1.14 0% $1.14 0% System Availability Charge/Bill $6.50 $5.22 -19% $4.68 -28% Compliance Charge/Bill $11.35 $11.35 0% $11.35 0% Volume Charge $/Ccf $1.66 $1.72 3% $1.59 -4.2% Impervious Area Charge $/Sq.Ft. $0.0000 $0.0000 Typical Residential Bill - 8 Ccf/Month $20.92 $20.12 -3.8% $18.54 -11.4% Typical Residential Impervious Area Fee $0.00 This is the simplest of all alternatives to implement and to support. It provides increased accuracy to the cost of wet weather flow as a percentage of total system cost in MSD rates. Alternative 1(b) - Wet Weather Volume Costs Recovered Using Impervious Area Charge Table 3-12 displays the total impervious area recorded in all five of MSD's service areas separated into customer class. This includes residential (including multi family) and non-residential (commercial and industrial). COM 3-20 1 P 203t4 MSD 43486 1.1 Cost Allocation Stud sFinal Rcpocaoclion3fins doc Section 3 Wet Weather Volume Cost Allocation Alternatives t i 1 1 1 t t 1 1 1 Table 3-12 MSD Wet Weather Cost Allocation & Rates Distribution of Estimated Wet Weather Flows to Capacity and Volume Impervious Area by Customer Class Impervious Area (Acres) % Impervious Commercial 19,630 34.2% Industrial 7,088 12.4% Multifamily 5,052 8.8% Single Family 25,507 44.4% Anheuser-Busch 122 0.2% Total 57,399 100.0% Using this distribution methodology will require a change in MSD's existing rate structure. This rate structure includes a charge per residential equivalent impervious area unit (equal to the average impervious area for a single family residence). The charges will be separate from and in addition to the wastewater rates. The basis for this alternative is the establishment of a clear relationship between wet weather flows (stormwater flows), and the allocation of the costs of handling these flows onto customers. As stated earlier there is a correlation of wet weather flows to impervious area. This distribution methodology attempts to capture that relationship and charge customers accordingly. In this alternative, the volume component of the wet weather cost is recovered using an impervious area charge. Table 3-13 displays the comparison of anticipated revenues from existing rates with the estimated revenues derived from existing rates plus the impervious area rates. Table 3-13 also presents the revenues required per customer class with stormwater costs excluded. In order to present the wastewater system costs separately, the column "Revision Without Stormwater Costs" does not include $13,657,602 in stormwater system costs. COM 3-21 1 P:120314 MSD 4348814 Cost Alow6on SludyTinal ReponlSMion3linal,doc Section 3 Wet Weather Volume Cost Allocation Alternatives 1 1 1 i 1 1 1 1 i 1 1 t Table 3-13 Alternative 1(b) MSD Wet Weather Cost Allocation & Rates Wet Weather Capacity Allocated by Customer - Volume by Impervious Area Comparative Rev Factors Utilized - I/I Allocation 33% Capacity 37% Volume 63% Revenue Comparison Existing Cost Of Service Revision Percent Change Revision Without Stormwater Costs Percent Change Metered Customers Single Family $72,704,600 $52,416,968 -27.9% $48,715,495 -33.0% Multifamily 19,269,000 15,027,236 -22.0% 13,996,172 -27.4% Non -Residential: Anheuser-Busch 7,566,700 6,059,913 -19.9% 5,879,293 -22.3% All Other 59,601,100 47,059,278 -21.0% 44,405,171 -25.5% Total $159,141,400 $120,563,395 $112,996,130 UnMetered Customers Single Family $16,871,000 $12,354,400 -26.8% $11,487,053 -31.9% Multi Family 10,327,500 7,822,191 -24.3% 7,279,803 -29.5% Total $27,198,500 $20,176,591 $18,766,856 Impervious Area Charles Single Family I $20,263,363 $18,183,431 Multifamily 4,013,164 3,601,233 Non -Residential: Anheuser-Busch 98,362 88,151 All Other 21,323,387 19,046,498 Total $45,599,913 $40,919,313 Total System Single Family $89,575,600 $85,034,731 -5.1% $78,385,979 -12.5% Multifamily 29,596,500 26,862,591 -9.2% 24,877,208 -15.9% Non -Residential 59,601,600 68,382,665 14.7% 63,451,669 6.5% Anheuser-Busch 7,566,700 6,158,275 -18.6% 5,967,444 -21.1% Total System $186,339,900 $186,339,896 -18.6% $172,682,299 Note that the there appears to be a significant decrease in revenue from all classes of customers in the metered and unmetered categories. This reflects the shifting of revenue from the wastewater rates to the impervious area charge. The actual affect of this alternative is presented under Total System. Non-residential would be expecting a ten percent increase and the other classes of customers would realize a decrease. Table 3-14 presents the existing and alternative rates as well as the estimated impact this alternative will have on typical single family residential bills. OEM 3-22 1 P.2o3I4 MSDWI486 14 Cost Alteration Study4Final Rcyort`Sccoonlfinal doc i Section 3 Wet Weather Volume Cost Allocation Alternatives i t 1 1 Table 3-14 Alternative 1(b) MSD Wet Weather Cost Allocation & Rates Wet Weather Capacity Allocated by Customer -Volume by Impervious Area Comparative R- Factors Utilized 4w. I/I Allocation 33% Capacity 37% Volume 63% Rate Comparison Existing Cost Of Service Revision Percent Change Revision without Stormwater Costs Percent Change Billing and Collection Charge/Bill $1.14 $1.14 0% $1.14 0% System Availability Charge/Bill $6.50 $5.22 -19% $4.69 -27.99% Compliance Charge/Bill $11.35 $11.35 0% $11.35 0% Volume Charge $/Ccf $1.66 $1.17 -30% $1.10 -33.95 Impervious Area Charge $/Sq.Ft. $0.0183 $0.0164 Typical Residential Bill - 8 Ccf/Month $20.92 $15.72 -25% $14.63 -30.25% Typical Residential Impervious Area Fee $3.80 $3.41 Alternative 1(c) - Wet Weather Volume and Subsidized Stormwater Costs - Impervious Area This alternative is the same as Alternative 1(b) but includes the portion of stormwater costs subsidized by the wastewater rates. Table 3-15 presents the comparison of anticipated revenues from existing rates with the estimated revenues revised from existing rates plus the impervious area rates. Table 3-15 also presents the revenues required per customer class with stormwater costs excluded. In order to present the wastewater system costs separately, the column "Revision Without Stormwater Costs" does not include $13,657,602 in stormwater system costs. C'DM 3-23 P:120314 MSD1434861.1 Cost Allocation Study\Final Repon\$ection38nal.0oc f Section 3 Wet Weather Volume Cost Allocation Alternatives i 1 1 a t i i 1 Table 3-15 Alternative 1(c) MSD Wet Weather Cost Allocation & Rates Wet Weather Volume & Subsidized Stormwater Costs Distributed by Impervious Area Comparative Revenue Factors Utilized Ill Allocation 33% Capacity 37% Volume 63% Revenue Comparison Existing Cost Of Service Revision Percent Change Revision Without Stormwater Costs Percent Change Metered Customers Single Family $72,704,600 $48,715,495 -33.0% $48,715,495 -33.0% Multifamily 19,269,000 13,996,172 -27.4% 13,996,172 -27.4% Non -Residential: Anheuser-Busch 7,566,700 5,879,293 -22.3% 5,879,293 -22.3% All Other 59,601,100 44,405,171 -25.5% 44,405,171 -25.5% Total $159,141,400 $112,996,130 $112,996,130 UnMetered Customers Single Family $16,871,000 $11,487,053 -31.9% $11,487,053 -31.9% Multi Family 10,327,500 7,279,803 -29.5% 7,279,803 -29.5% Total $27,198,500 $18,766,856 $18,766,856 Impervious Area Charges Single Family $24,252,498 $18,183,431 Multifamily 4,803,213 3,601,233 Non -Residential: Anheuser-Busch 117,176 88,151 All Other 25,404,026 19,046,498 Total $54,576,913 40,919,313 Total System Single Family $89,575,600 $84,455,045 -5.7% $78,385,979 -12.5% Multifamily 29,596,500 26,079,188 -11.9% 24,877,208 -15.9% Non -Residential 59,601,100 69,809,197 +17.1% 63,451,669 6.5% Anheuser-Busch 7,566,700 5,996,469 -20.8% 5,967,444 -21.1% Total System $186,339,900 $186,339,896 $172,682,299 This has the affect of increasing rate revenue slightly more for non-residential customers compared to Alternative 1(b). A part of this increase comes from the updated percentage of wet weather flows which decreased the percent from 45 to 33. CNA 3-24 i P:120314 MSD1434861.1 Cot Allocation SIu0lFinal Rcpon\Scction3final don 1 Section 3 Wet Weather Volume Cost Allocation Alternatives i i i t Table 3-16 presents the existing and alternative rates as well as the estimated impact this alternative will have on typical single family residential bills. Table 3-16 Alternative 1(c) MSD Wet Weather Cost Allocation & Rates Wet Weather Volume & Subsidized Stormwater Costs Distributed by Impervious Area Comparative Rates Factors Utilized Ill Allocation 33% Capacity 37% Volume 63% Rate Comparison Existing Cost Of Service Revision Percent Change Revision without Stormwater Costs Percent Change Billing and Collection Charge/Bill $1.14 $1.14 0% $1.14 0% System Availability Charge/Bill $6.50 $4.69 -28% $4.69 -28% Compliance Charge/Bill $11.35 $11.35 0% $11.35 0% Volume Charge $/Ccf $1.66 $1.10 -34% $1.10 -33.95 Impervious Area Charge $/Sq.Ft. $0.0218 $0.0164 Typical Residential Bill - 8 Ccf/Month $20.92 $14.63 -30.1% $14.63 -30% Typical Residential Impervious Area Fee $4.55 $3.41 3.5.2 Alternative 2 - 8-Inch-Foot Equivalent Capacity Allocation Table 3-17 presents the total inch -feet of collection system recorded by MSD for both sanitary and combined systems (Section 2.1.2). CDM has calculated the equivalent 8- inch-foot of pipe based on this information and determined a customer/capacity allocation factor. 3-25 P:120314 MS0143486 I-1 Cost Allocation SludytFinal RepoalSection3fmal.doc 0 Section 3 Wet Weather Volume Cost Allocation Alternatives t t t Table 3-17 Alternative 2(a) MSD Wet Weather Cost Allocation & Rates Distribution of Estimated Wet Weather Flows to Capacity and Volume Capacity Based on Minimum 8-inchfeet of S t P' Description ys Pipe Size/Length em ipe Allocation Factors Combined Capacity Volume Pipe Size Various' 8 inch2 Length 7,766,052 7,766,052 Total inch -feet 181,407,190 62,128,416 Sanitary Pipe Size Various [1] 8 inch Length 23,088,498 23,088,498 Total inch -feet 230,209,709 184,707,984 Combined & Sanitary Total Feet of Pipe 30,854,550 30,854,550 Total inch -feet 411,616,899 246,836,400 60% 40% From 1 inch through 196-Inch diameter pipe. Total inch -feet equals length of pipeline in system times respective diameter in inches. 2 Total inch -feet equals length times 8 (inches). The allocation factors determined in this alternative are 60 percent to customer/capacity and 40 percent to volume. This is a significant shift from the existing allocation factors of 37 percent customer/capacity and 40 percent volume. These results indicate that a major portion of MSD's collection system is dedicated to conveying both wastewater and wet weather flows at a minimum level of service. This minimum level of service is common to all customers. Alternative 2 (a) - Existing Rates Table 3-18 provides a comparison of revenues derived from existing rates versus estimated revenues derived using the allocation factors determined for this alternative. Table 3-18 also presents the revenues required per customer class with stormwater costs excluded. In order to present the wastewater system costs separately, the column "Revision Without Stormwater Costs1l does not include $13,657,602 in stormwater system costs. oeM 3-26 P.120314 MS13,434861.1 Cosi Allocation Studyffivat Rcyort'Soction3rin41 doc Section 3 Wet Weather Volume Cost Allocation Alternatives A 1 1 1 1 1 a 1 1 1 Table 3-22 Alternative 2(c) MSD Wet Weather Cost Allocation & Rates Wet Weather Volume & Unfunded Stormwater Costs Distributed by Impervious Area 8-Inch-Foot Pipe Allocation Comparative Revenue Factors Utilized , Ill Allocation 33% Capacity 60% Volume 40% Revenue Comparison Existing Cost Of Service Revision Percent Change Revision Without Stormwater Costs Percent Change Metered Customers Single Family $72,704,600 $60,018,746 -17.4% $60,018,746 -17.4% Multifamily 19,269,000 14,393,756 -25.3% 14,393,756 -25.3% Non -Residential: Anheuser-Busch 7,566,700 5,978,328 -21.0 5,978,328 -21.0% All Other 59,601,100 44,614,953 -25.2% 44,614,953 -25.2% Total $159,141,400 $125,005,783 $125,005,783 UnMetered Customers Single Family $16,871,000 $13,672,418 -19.0% $13,672,418 -19.0% Multi Family 10,327,500 8,023,582 -22.3% 8,023,582 -22.3% Total $27,198,500 $21,696,000 $21,696,000 Impervious Area Charges Single Family $17,613,726 $11,545,035 Multifamily 3,488,402 2,286,497 Non -Residential: Anheuser-Busch 85,210 55,901 All Other 18,450,778 12,093,082 Total $39,638,116 $25,980,516 Total System Single Family $89,575,600 $91,304,890 1.9% $85,236,200 -4.8% Multifamily 29,596,500 25,905,740 -12.5% 24,703,835 -16.5% Non -Residential 59,601,100 63,065,731 +5.8% 56,708,035 -20.3% Anheuser-Busch 7,566,700 6,063,538 -19.9% 6,034,225 -4.8% Total System $186,339,900 $186,339,899 $172,682,295 The multi family customer class appears to realize a significant decrease in rates compared to the other two classes of customers that would experience a slight increase with this alternative. Table 3-23 presents the rates using this alternative and modified rate design to include impervious area rates to recover wet weather volume and subsidized stormwater related charges. 3-31 1 P:@0314 MSD1434881.1 Cost AJccation Studffinal RepomSec on3final.doc Section 3 Wet Weather Volume Cost Allocation Alternatives a a i e I 7 i 1 1 a 1 t Table-3-23 Alternative 2(c) MSD Wet Weather Cost Allocation & Rates Wet Weather Volume & Unfunded Stormwater Costs Distributed by Impervious Area, Impervious Area Rate Comparison Comparative Rates Factors Utilized I/I Allocation 33% Capacity 60% Volume 40% Rate Comparison. Existing Cost Of Service Revision Percent Change Revision without Stormwater Costs Percent Change Billing and Collection Charge/Bill $1.14 $1.14 0% $1.14 0% System Availability Charge/Bill $6.50 $7.60 18% $7.60 18% Compliance Charge/Bill $11.35 $11.35 0% $11.35 0% Volume Charge $/Ccf $1.66 $1.10 -34% $1.10 -34% Impervious Area Charge $/Sq.Ft. $0.0159 $0.0104 Typical Residential Bill - 8 Ccf/Month $20.92 $17.54 -16% $17.54 -16% Typical Residential Impervious Area Fee $3.30 $2.16 3.5.3 Alternative 3 - Capacity allocation based on 50-fool/6-inch Lateral This alternative is similar to the previous alternative except it allocates wet weather costs assuming that all customer connections have a minimum equivalent of a six inch diameter, 50-foot lateral. The number of inch -feet connections are totaled and added to the calculated inch -foot collection system determined in Alternative 1. The total of the inch -feet of laterals is divided by the inch -feet of collection system plus laterals. The quotient is the allocation factor for customer/capacity. Table 3-24 provides the calculation of the wet weather allocation factors with this alternative. `'M 3-32 P120314 MSDVI3486 Id Cost Allocution Study.Finul RcportScotion?ftnul.doc i Section 3 Wet Weather Volume Cost Allocation Alternatives i t t t t Table 3-24 Alternative 3 MSD Wet Weather Cost Allocation & Rates Distribution of Estimated Wet Weather Flows to Capacity and Volume Capacity Based on 50-Feet of 6-Inch Diameter Laterals Description Allocation Total Bills 5,159,292 Months 12 # Connections 429,941 Average Lateral inch-ft.1 300 Total Lateral inch-ft.2 128,982,300 24% Capacity Volume Total System inch-ft.3 411,616,899 76% System & Lateral 540,599,199 1 Average lateral inch -feet equals 50-foot length times (6-inch diameter). 2 Total lateral inch -feet equals 300 times number of connection. 3 Total system inch -feet length from Table 3-16. This alternative distributes the wet weather costs with an estimated 24 percent to customer/ capacity and 76 percent to volume. This allocates more costs onto the volume component of the existing rate design. Alternative 3(a) Existing Rates Table 3-25 provides the revenues derived from existing rates compared to estimated revenues determined using the allocation factors for this alternative. Table 3-25 also presents the revenues required per customer class with stormwater costs excluded. In order to present the wastewater system costs separately, the column "Revision Without Stormwater Costs" does not include $13,657,602 in stormwater system costs. 1 1 CDM 3-33 P:t20314 MSOW34861.1 Cost Allocation Sto sytFinal Repont$ect,on3finat doc Section 3 Wet Weather Volume Cost Allocation Alternatives 1 1 1 1 i i t t t t t t t Table 3-25 Alternative 3(a) MSD Wet Weather Cost Allocation & Rates Distribution of Estimated Wet Weather Flows to Capacity and Volume Capacity Based on 50-Feet of 6-Inch Diameter laterals Comparative Revei Factors Utilized - III Allocation 33% Capacity 24% Volume 76% Revenue Comparison Existing Cost Of Service Revision Percent Change Revision Without Stormwater Costs Percent Change Metered Customers Single Family $72,704,600 $66,760,514 -8.2% $61,586,748 -15.3% Multifamily 19,269,000 20,465,206 6.2% 18,875,961 -2% Non -Residential: Anheuser-Busch 7,566,700 8,231,305 8.8% 7,827,802 3.5% All Other 59,601,100 64,522,006 8.2% 60,075,440 0.8% Total $159,141,400 $159,979,031 $148,365,951 UnMetered Customers Single Family $16,871,000 $15,958,377 -5.4% $14,721,098 -12.7% Multi Family 10,327,500 10,402,492 0.7% 9,595,250 -7.1% Total $27,198,500 $26,360,868 $24,316,348 Impervious Area Charges Single Family Multifamily Non -Residential: Anheuser-Busch All Other • Total Total System Single Family $89,575,600 $82,718,890 -7.6% $76,307,846 -14.8% Multifamily 29,596,500 30,867,697 4.3% 28,471,211 -3.8% Non -Residential 59,601,100 64,522,006 8.2% 60,075,440 8% Anheuser-Busch 7,566,700 8,230,305 8.8% 7,827,802 3.5% Total System $186,339,900 $186,339,899 $172,682,299 This alternative increases the cost of service to large billable volume customers. Conversely, it decreases the cost to the smaller customers. Multi family customers will have an increase, albeit small, in their bills. Table 3-26 presents the rate changes affected by this alternative. COM 3-34 Pd26314 MSD43486I-1 CCSI AllOCaliall S,udyFinal Repot Smionifinl doc Section 3 Wet Weather Volume Cost Allocation Alternatives t t t t t t Table 3-26 Alternative 3(a) MSD Wet Weather Cost Allocation & Rates Distribution of Estimated Wet Weather Flows to Capacity and Volume Capacity Based on 50-Feet of 6-Inch Diameter Laterals Comparative Rat Factors Utilized vV I/I Allocation 33% Capacity 24% Volume 76% Rate Comparison Existing Cost Of Service Revision Percent Change Revision without Stormwater Costs Percent Change Billing and Collection Charge/Bill $1.14 $1.14 0% $1.14 0% System Availability Charge/Bill $6.50 $3.39 -47.8% $3.04 -53.2% Compliance Charge/Bill $11.35 $11.35 0% $11.35 0% Volume Charge $/Ccf $1.66 $1.83 10% $1.69 1.8% Impervious Area Charge $/Sq.Ft. 11 $0.0000 $0.0000 Typical Residential Bill - 8 Ccf/Month $20.92 $19.17 -8.4% $17.70 -15.4% Typical Residential Impervious Area Fee $0.00 $0.00 Alternative 3(a) indicates an eight percent decrease in typical residential bills. Again, the customers with large contributed volume will have a considerable increase. There are some intra-class inequities for the residential customers using this alternative; multi -family customers with a slight increase in the cost of wet weather and single family residents a decrease. In addition, large commercial and industrial customers will see larger increases in wet weather costs compared to those commercial customers with smaller billable volumes. Alternative 3(b) - Wet Weather Volume Costs Recovered Using Impervious Area Charge Table 3-27 displays the revenue from existing rates compared to revenue derived from rates with wet weather volume charges passed onto customers based on impervious area. Table 3-27 also presents the revenues required per customer class with stormwater costs excluded. In order to present the wastewater system costs separately, the column "Revision Without Stormwater Costs" does not include $13,657,602 in stormwater system costs. 3-35 t P:120314 MSD1434661.1 Cost Allocation Stuoy\Finat Repol\Section3final Doc• Section 3 Wet Weather Volume Cost Allocation Alternatives 1 1 1 1 t t 1 Table 3-27 Alternative 3(b) Capacity Based on 50-Feet of 6-Inch Width Laterals Comparative Wet Weather Capacity Allocated by Customer - Volume by Impervious Area Revenue Comparison Factors Utilized I/1 Allocation 33% Capacity 24% Volume 76% Revenue Comparison Existing Cost Of Service Revision Percent Change Revision Without Stormwater Costs Percent Change Metered Customers Single Family $72,704,600 $45,297,391 -37.7% $42,326,707 -41.8% Multifamily 19,269,000 14,776,805 -23.3% 13,771,446 -28.5% Non -Residential: Anheuser-Busch 7,566,700 5,997,540 -20.8% 5,823,322 -23% All Other 59,601,100 46,927,167 -21.3% 44,286,622 -25.7% Total $159,141,400 $112,998,903 $106,208,097 UnMetered Customers Single Family $16,871,000 $10,977,889 -35.0% $10,251,833 -39.2% Multi Family 10,327,500 7,353,711 -28.8% 6,859,411 -33.6% Total $27,198,500 $18,331,600 $17,111,244 Impervious Area Charges Single Family $24,444,682 $21,935,558 Multifamily 4,841,275 4,344,342 Non -Residential: Anheuser-Busch 118,251 106,119 All Other 25,605,189 22,976,939 Total $55,009,397 $49,362,958 Total System Single Family $89,575,600 $80,719,961 -9.9% $74,514,097 -16.8% Multifamily 29,596,500 26,971,790 -8.9% 24,975,199 -15.6% Non -Residential 59,601,100 72,532,356 21.7% 67,263,561 12.9% Anheuser-Busch 7,566,700 6,115,791 -19.3% 5,929,441 -21.6% Total System $186,339,900 $186,339,898 $172,682,298 Table 3-28 presents the rates using this alternative and modified rate design to include impervious area rates to recover wet weather volume related charges. COM 3-36 P:12O3 II MSD14]48614 Cost .4ltoc4ion SsuO,'Fin l Rccon,Scctionlrm I d.c Section 3 Wet Weather Volume Cost Allocation Alternatives i 1 1 1 t t i i Table 3-28 Alternative 3(b) Capacity Based on 50-Feet of 6-Inch Width Laterals Comparative Wet Weather Capacity Allocated by Customer -Volume by Impervious Area Com arative Rat Factors Utilized p es Ill Allocation 33% Capacity 24% Volume 76% Rate Comparison Existing Cost Of Service Revision Percent Change Revision without Stormwater Costs Percent Change Billing and Collection Charge/Bill $1.14 $1.14 0% $1.14 0% System Availability Charge/Bill $6.50 $3.39 -47.8% $3.04 -53.2% Compliance Charge/Bill $11.35 $11.35 0% $11.35 0% Volume Charge $/Ccf $1.66 $1.17 -30% $1.10 -33.7% Impervious Area Charge $/Sq.Ft. 1 $0.0220 $0.0197 Typical Residential Bill - 8 Ccf/Month $20.92 $13.89 -33.6% $12.98 -38% Typical Residential Impervious Area Fee $4.59 $4.11 The net affect of this alternative on a typical single family residential bill is approximately a 12 percent decrease (wastewater plus impervious area charge compared to existing bill). Non-residential customers will realize a significant increase. Alternative 3(c) - Wet Weather Volume and Unfunded Stormwater Costs - Impervious Area Table 3-29 displays the revenue from existing rates compared to revenue derived from rates with wet weather volume and subsidized stormwater costs included in the wastewater rate passed onto customers based on impervious area. Table 3-29 also presents the revenues required per customer class with stormwater costs excluded. In order to present the wastewater system costs separately, the column "Revision Without Stormwater Costs" does not include $13,657,602 in stormwater system costs. COM 3-37 1 P:120314 MSD.43466 1.1 Cost allocation Stu0y\Final ReponlSection3finaLEnc 1 Section 3 Wet Weather Volume Cost Allocation Alternatives 1 1 1 1 i 1 1 1 1 1 1 1 1 1 1 Table 3-29 Alternative 3(c) MSD Wet Weather Cost Allocation & Rates Wet Weather Volume & Unfunded Stormwater Costs Distributed by Impervious Area 8-Inch-Foot Pipe Allocation Comparative Revenue Factors Utilized I/I Allocation 33% Capacity Volume 24% 76% Revenue Comparison Existing Cost Of Service Metered Customers Revision Percent Change Revision Without Stormwater Costs Percent Change Single Family Multifamily Non -Residential: $72,704,600 19,269,000 $42,326,707 13, 771,446 -41.8% -28.5% $42,326,707 13,771,446 -41.8% -28.5% Anheuser-Busch 7,566,700 5,823,322 -23.0% All Other 59,601,100 44,286,622 -25.7% Total $159,141,400 $106,208,097 UnMetered Customers 5,823,322 44,286,622 $106,208,097 -23.0% -25.7% Single Family Multi Family Total $16,871,000 10,327,500 $27,198,500 $10,251,833 6,859,411 $17,111,244 -39.2% -33.6% Impervious Area Charges Single Family Multifamily Non -Residential: $28,004,413 5,546,280 $10,251,833 6,859,411 $17,111,244 $21,935,558 4,344,342 -39.2% -33.6% Anheuser-Busch 135,479 All Other 29,334,386 Total $63,020,558 Total System Single Family Multifamily Non -Residential $89,575,600 29,596,500 59,601,100 $80,582,953 26,177,137 73,621,008 -10.0% -11.6% 23.5% 106,119 22,976,939 $49,362,958 $74,514,097 Anheuser-Busch 7,566,700 5,958,801 -21.2% 24,975,199 67,263,561 Total System $186,339,900 $186,339,899 5,929,441 -16.8% -15.6% $172,682,298 12.9% -21.6% This alternative creates a significant increase for the non-residential class of customer while providing a rate decrease of over 10 percent for residential and multi family class customers. There is a significant shift in the revenue requirement recovered from the non-residential class compared to residential and multi family, producing some perceived inter -class inequity. CDMI 3-38 1 P.\20314 MSD143a861-I Cost Allocation SludyFinal Ropon`Soclionlfinal.doc Section 3 Wet Weather Volume Cost Allocation Alternatives i i 1 1 i a 1 1 1 1 Table 3-30 presents the rates using this alternative and modified rate design to include impervious area rates to recover wet weather volume and subsidized stormwater related charges. Table 3-30 Alternative 3(c) MSD Wet Weather Cost Allocation & Rates Wet Weather Volume & Unfunded Stormwater Costs Distributed by Impervious Area Impervious Area Rate Comparison Factors Utilized Ill Allocation 33% Capacity 24% Volume 76% Rate Comparison Existing Cost Of Service Revision Percent Change Revision without Stormwater Costs Percent Change Billing and Collection Charge/Bill $1.14 $1.14 0% $1.14 0% System Availability Charge/Bill $6.50 $3.04 -53.2% $3.04 -53.2% Compliance Charge/Bill $11.35 $11.35 0% $11.35 0% Volume Charge $lCcf $1.66 $1.10 -34% $1.10 -33.7% Impervious Area Charge $/S•.Ft. $0.0252 $0.0197 Typical Residential Bill - 8 Ccf/Month $20.92 $12.98 -38% $12.98 -38% Typical Residential Impervious Area Fee $5.25 $4.11 3.6 Conclusion The first alternative group was designed to develop the range of changes in rates from different wet weather cost allocation factors, i.e., the second primary factor used by the MSD rate model to determine wet weather costs allocated to capacity or volume functions (37/63 ratio). It clearly demonstrated that changing the existing allocation factor from the existing 37/63 to 100 percent volume and 0 percent capacity would increase the large volume/non-residential customer rates about 17 percent and decrease residential rates by about 16 percent. On the other hand, changing the existing allocation factor to 0 percent volume and 100 percent capacity will create a 29 percent decrease in non-residential rates and a 27 percent increase in residential rates. This defines the range of rate change that can be expected from changing the wet weather cost allocation factor. COM 3-39 1 P:120314 MSD143486 I -I Cost Allocation Sluay1Final RepookSeaion3final.00c Section 3 Wet Weather Volume Cost Allocation Alternatives a 1 i i t 1 t In addition to evaluating supportable changes in the primary wet weather allocation factors included in the rate model, CDM included several alternatives designed to investigate rate structure enhancements. These alternatives were intended to offer increased equity relating to wet weather and stormwater costs. Specifically, the alternatives include adding an impervious area charge rate component to the current wastewater rate structure. These along with other relevant alternatives will be ranked in Section 4 of this study using four criteria. The alternatives ranked will be Alternatives 1 through 3, including the Existing Rate Model (A) and subsets identified in each alternative. COM 3-40 1 P.V0314 MSDW34S61.1 Cost Allocoion Stndyfinal Ropon'ation3ftnal,doc t 1 1 1 1 1 i Section 4 Allocation Alternative Comparison 4.1 Introduction Tables 4-1 and 4-2 present impacts to the rate categories and to customer classes for the various alternatives. Matrix Conclusions and Preferred Alternative Identification The alternatives described in Section 3 were screened using a decision matrix. To evaluate and rank the alternatives, four basic criteria were identified and defined. These criteria included: • Rate Impact; • Class Equity which included both Inter -Class Equity and Intra-Class Equity; • Ratemaking Methodology; and • Administrative Simplicity. Each of the four ranking criteria have been developed taking into consideration the criteria put forth to govern rates in the MSD Rate Commission Charter. The Rate Commission Criteria states that any proposed rate adjustment recommended by the Rate Commission for approval by the MSD Board will: 1. Be consistent with constitutional, statutory or common law as amended from time to time; 2. Enhance the District's ability to provide adequate sewer and drainage systems and facilities, or related services; 3. Be consistent with and not in violation of any covenant or provision relating to any outstanding bonds or indebtedness of the District; 4. Not impair the ability of the District to comply with applicable Federal or State laws or regulations as amended from time to time; and 5. Impose a fair and reasonable burden on all classes of rate payers. The criteria pertinent to legal and regulatory compliance was not included in the evaluation as all of the alternatives meet this standard. There are issues relative to the ability to legally challenge the alternatives; however, this issue is best addressed in a legal forum. 4-1 P:12o314 MS0143486 t-t Cost Allocation Stuoffinat ReporSenion4finaLaoc 1 1 1 i i t i 1 ti Section 4 Allocation Alternative Comparison ✓4.2 Evaluation Criteria and Ranking Methodology The four criteria used to rank the alternatives identified in this study are designed to address the Rate Commission Charter mandates. A description of the evaluation factors used to rank the alternatives and the method for assigning point values to each criterion is presented in the following sections. 4.2.1 Rate Impact The Rate Impact of the Wet Weather Cost Allocation alternatives has been evaluated based on the change in monthly cost to single family customers. The mean value (increase or decrease) in monthly cost for single family customer was determined by calculating the change in monthly revenue allocation to the single family customer class, divided by the number of single family customers. Rate Impact is one of two factors used to evaluate whether the proposed alternatives adequately address criteria number 5 of the Rate Commission, "Impose a fair and reasonable burden on all classes of rate payer." The standard deviation for the single family monthly costs (increase or decrease from existing costs) was calculated against zero (0). A numeric ranking from 10 (the alternative with the lowest standard deviation) to 1 (for the alternative for the largest standard deviation) was assigned to each alternative in descending order. Options that have the same standard deviation were give the same ranking and the next lowest ranked alternative given the next lower number. The standard deviation for each alternative and its ranking are shown in Table 4-1. Table 4-1 XRate Impact Changes to Single Family Bill Standard Deviation and Evaluation Alternative Existing 1a lb 1c 2a 2b _ 2c 3a 3b 3c Bill Variance $(s) 0 -0.61 -0.31 -0.31 0.86 1.05 1.05 -1.44 -1.08 -1.08 Standard Deviation 0 0.431 0.219 0.219 0.608 0.742 0.742 1.018 0.764 0.764 Score 10 8 9 9 7 6 6 4 5 5 Rate Impact Criteria Weighting Rate Impact is one measurement of cost distribution and how the rate alternatives would impact specific category of rate payers. The criteria pertinent to Rate Impact has been given a 20 percent weight in the evaluation matrix. 4-2 i P:120314 MS0143488 1.1 Cost Allocation StudysFinal ReponlSection4fina1.0oc Section 4 Allocation Alternative Comparison 4.2.2 Ratemaking Methodology The Ratemaking criteria is used to quantify how supportable the information is that was used for establishing and defining capacity, volume and wet weather volume functions in MSD's rate model and distributing volume costs to the customer classes. This factor is also used to quantify the relative accuracy of the information based on rate setting standards that recommend costs be allocated in terms of cost causing factors, with the factors used being of a quantifiable nature. For example, the total length of laterals was based on assumed length of each lateral and it was assumed each account had one lateral. This information was not field verified or tested as part of this study and would be given a lower score. In contrast, the total system length of 8-inch pipe was based on MSD asset inventory and on MSD system maps. While no field verification was conducted as part of this study, the inventory is based on system information, which increases its reliability. Accordingly, the options that use 8-inch pipe, feet as a basis for determining capacity and volume function would score higher. Ratemaking methodology relates to criteria number 2 of the Rate Commission, "a rate adjustment should enhance the District's ability to provide adequate sewer and drainage systems and facilities or related services." Each alternative was given a score of 10 and 2 points were deducted for each of these factors: • Stormwater cost distributed by billed volume; • Use of current 45/55 percent, Wet weather/Wastewater factor; • Wet weather volume costs distributed based on billed volume; • Use of current 33/67 percent, distribution of capacity/volume costs; • Use of laterals length assumptions as basis of capacity/volume costs. Ratemaking Methodology Weighting Factor Ratemaking Methodology was used to quantify how supportable the information is that was used for establishing and defining capacity, volume and wet weather volume functions in MSD's rate model and distributing volume costs to the customer classes Ratemaking Methodology criteria has been given a 40 percent weight in the evaluation matrix criterion. 4.2.3 Class Equity Inter -Class Equity This is designed to address the Rate Commission Charter mandate Number 5 - any proposed rate adjustment will impose a fair and reasonable burden on all classes of ratepayers. When evaluating rate structures one of the fundamental requirements is the equitable distribution of utility costs to all customers based on customer's demand characteristics. Equitable rate structures attempt to eliminate or at least limit cross 4-3 PA20314 MS0143486 I -I Cost Allocation StudyiFinaI Report\Section4final.0oc Section 4 Allocation Alternative Comparison i 1 I i i 1 Y i i a i r a i CDPAI subsidization (or the appearance of such) between customer classes. This is called vertical equity, e.g. industrial customers are not subsidizing rates for residential customers or vice versa. The measurement used to rank the alternatives in the inter -class equity criteria was based on the mean value (increase or decrease in rates) for each customer class and then the standard deviation was calculated for the composite of customer class mean values for each alternative. The mean (increase or decrease) in monthly cost for each customer class was determined by calculating the change in monthly revenue allocation to that customer class, divided by the number of customers in that class. The standard deviation is an objective measure for ranking alternatives under the inter -class equity criteria and judges the overall impact the change in rates have on any one customer class compared to others. As an example, if a rate adjustment is proposed that shifts the revenue requirement recovery from residential to non- residential customers by 10 percent or more this would be considered inequitable (compared to alternatives with less of a shift in revenues) and score low in ranking. This low score would be given even though there may be clear justification for the change in cost allocation. This is because the shift would create a "rate shock" in the non-residential class of customer and perhaps send the wrong price signals to the residential customers. A numeric ranking from 10 (being the alternative with the lowest standard deviation) to 1 (for the alternative for the highest standard deviation) was assigned to each alternative in descending order. Options that have the same standard deviation were give the same ranking and the next lowest ranked alternative given the next lower number. The standard deviation for each alternative and its ranking are shown in Table 4-2. Table 4-2 Inter -Class Equity Changes to Customer Class Costs Standard Deviation and Evaluation Score Alternative Existing la lb lc 2a 2b 2c 3a 3b 3c Single Family Variance $(s) 0.0 -0.61 -0.31 -0.31 0.86 1.05 1.05 -1.44 -1.08 -1.08 Multi Family Variance $(s) 0.0 0.83 -6.72 -6.72 -1.48 -6.72 -6.72 2.13 -6.98 -6.98 Non - Residential Variance $(s) 0.0 7.1 16.01 16.01 -9.42 -3.76 -3.76 16.44 27.19 27.19 Standard Deviation 0.0 4.01 11.72 11.72 5.39 3.72 3.72 9.46 18.27 18.27 Score 10 9 5 5 7 8 8 6 4 4 Intra-Class Equity 4-4 P:120314 MSDt43488 61 Cost Allocation StudttFinal Repo t'Secuon4fnalAoc 1 1 t 1 1 1 1 1 i i 1 1 1 1 1 Section 4 Allocation Alternative Comparison The intra-class equity ranking criteria is also designed to address the Rate Commission Charter mandate Number 5 - any proposed rate adjustment will impose a fair and reasonable burden on all classes of ratepayers. In many cases evaluating the vertical equity is not enough to determine the fairness of a rate structure. With larger utilities that have numerous customers, customers within a class will not always have the same demand characteristics. This then leads to intra-class subsidization situations. This is called horizontal equity, i.e., customers within a class are not supporting other customers in the same customer class. The principal measure of equity using the intra-class ranking criterion was a review of the typical billing summary prepared for each alternative. This summary determines what typical bill ratepayers will be charged based on different levels of service and compares them to charges using existing (baseline) rates. Multiple levels of billable volumes and pollutant strengths were used in the summary in Appendix B to capture the range of impacts between customer classes and within customer classes. The summary of typical bills is presented in Appendix B. The typical bills are based on the accounts and information presented to the Stormwater Advisory Committee meetings conducted in the spring of 2001. Significant increases or decreases within classes will reduce the ranking in the intra-class equity criteria. The mean value (increase or decrease in rates) was calculated for each single family _ customer type identified in Appendix B. The standard deviation was then calculated for the single family customer class as a composite for each alternative. The same procedure was followed for non-residential customers, however, only the following customer types were analyzed: • Tax Exempt Annexed Area - 25 ccf; • Tax Exempt Annexed Area - 50 ccf; and • High Rise Commercial -1,000 ccf. There was no multi -family customer information in Appendix B; therefore the mean value for the average of multi -family customers was used. The standard deviation for each customer class was then weighted based on each customer class's percent of the total annual bills and the weighted standard deviations summed. The standard deviation for each alternative and its ranking are shown in Table 4-3. P:120314 MSD143486 I I Cost Allocation Stnd?Final ReponlSection4final.doc 4-5 s Section 4 Allocation Alternative Comparison 1 1 1 1 1 1 i t i Table 4-3 Intra-Class Equity Changes to Customer Class Billings Standard Deviation and Evaluation Score Alternative Customers Bills 2005 Estimate Existing 1a lb 1c 2a 2b 2c 3a 3b 3c Single Family 4,315,770 (83.65%) 0 0.336 0.97 0.97 0.54 1.08 1.08 0.83 1.14 1.14 Multi- Family 535,550 (10.38%) 0 0.59 4.75 4.75 1.05 4.43 4.43 1.51 4.94 4.94 Non- Residential 307,972 (5.97) 0 38.06 115.31 115.31 61.35 158.72 158.72 94.26 90.79 90.79 Weighted Standard Deviation 0 2.62 8.19 8.19 4.22 10.84 10.84 6.48 6.88 6.88 Score 10 9 5 5 8 4 4 7 6 6 Inter -Class Equity Criteria and Intra-Class Equity Criteria Weighting Inter -class and Intra-class equity criterion was scored from 1 though 10 (10 being the most favorable) as described above. The score for the Inter and Intra-class equity was given the same weight and averaged to determine each alternative ranking. Table 4-4 provides the averaged score for each alternative. This average was used to rank each - alternative for the Class Equity criteria. The Class Equity criteria have been given a 20 percent weight in the evaluation matrix. CDM reviewed the alternatives using measures to determine the vertical equity it offers. Each alternative had the opportunity to be ranked in the inter -class equity criteria. Table 4-4 Class Eauit Alternative Existing 1a lb 1c 2a 2b - J 2c 3a 3b 3c Inter Class Equity 10 9 5 5 7 8 8 6 4 4 Intra Class Equity 10 9 5 5 8 4 4 7 6 6 Class Equity Score 10 9 5 5 7.5 6 6 6.5 5 5 4.2.4 Administrative Simplicity The administrative simplicity criteria addresses Rate Commission Charter criteria Number 2 - a rate adjustment should enhance the District's abilihj to provide adequate sewer and drainage systems and facilities, or related services. One of the factors to consider when evaluating a rate structure is the utility's ability to implement any change in the billing process that the alternative rate structure requires. It is also important that a change in rate structure be easy for the public to understand and accept. Each alternative was given a score of 10 and 2 points were deducted for each of these factors: CDM 4-6 Pd2031,1 MSDt434061.t Cost Altocatwn Stu°y1Final RepontSectioMbnat.°oc *ma mire mid mod mod wadi end rod OW m iiai lit WINO 011110 M Mr Wi mil' Table 4-5 Existing Rate Structure and Alternative 1, 37/63 Percent CapacityNolume Allocation Wastewater Allocation Alternative Evaluation Matrix No. Alternative Description Rate Impact (a) (c) Ratemaking Methodology Class Equity (b) (c) Administrative Simplicity 8 - existing rate structure and billing process Weighted = 0.80 Total Weight 6.60 A 45% Wet Weather Allocation 37/63 CapacityNolume Allocation Existing Rate Structure. 10 Weighted = 2.00 2- Wet Weather and capacity and volume cost allocations not supported on engineering/economic basis Weighted = 0.80 10 Weighted = 3.00 1(a) 33% Wet Weather Allocation 37/63 CapacityNolume Allocation Updated Wet Weather Flow Percentage Wet Weather Volume Cost Allocated Based on Billed Volume 8 Weighted = 1.6 4- capacity/volume allocation not support ed on engineering/economic basis Weighted = 1.60 9 Weighted = 2.70 8- existing rate structure and billing process Weighted = 0.80 6.70 1(b) 33% Wet Weather Allocation 37/63 CapacityNolume Allocation Updated Wet Weather Flow Percentage Wet Weather Volume Cost Allocated Based on Impervious Area 9 Weighted = 1.80 6 - increase equity adding impervious area charge Weighted = 2.40 5 Weighted = 1.50 2 - requires impervious area billing software modifications Weighted = 0.20 5.90 1(c) 33% Wet Weather Allocation 37/63 CapacityNolume Allocation Updated Wet Weather Flow Percentage Wet Weather Volume and Subsidized Stormwater Cost Allocated Based on Impervious Area 9 Weighted = 1.80 8 - increase equity adding impervious area charge for stormwater costs Weighted = 3.20 5 Weighted = 1.50 8 - requires impervious area billing software modifications Weighted = 0.80 7.30 Maximum Score 10 10 10 10 Weighting Factors 20% 40% 30% 10% (a) Rate Impact is based on the Standard Deviation of the Average Single Family Residentia bill. (b) Class Equity is based on the Average of (Standard Deviation of an Inter Class calculation plus the Standard Deviation Infra Class calculation (weighted per percent of bills)). (c) Rate Impact and Class Equity are based on wastewater revenue for the customer class evaluated. _& ■ ai soma mod use Dui ..■ramill mid aid NNW wad mat tlllN ball M Table 4-6 Alternative 2 Minimum 8-Inch-Feet of System Pipe - Wastewater Allocation Alternative Evaluation Matrix No. Alternative Description Rate Impact (a) (c) Ratemaking Methodology Class Equity (b) (c) Administrative Simplicity Total Weight 2(a) 33% Wet Weather Allocation 60/40 CapacityNolume Allocation Updated Wet Weather Flow Percentage Wet Weather Volume Cost Allocated Based on Billed Volume 7 Weighted = 1.40 4- wet weather flow and wet weather cost allocation factors supportable Weighted = 1.60 7.5 Weighted = 2.25 8 - existing rate structure and billing process Weighted = 0.80 6.05 2(b) 33% Wet Weather Allocation 60/40 CapacityNolume Allocation Updated Wet Weather Flow Percentage Wet Weather Volume Cost Allocated Based on Impervious Area 6 Weighted = 1.20 8 - wet weather flow and wet weather cost allocation factors supportable Weighted = 3.20 6 Weighted = 1.80 2 - requires impervious area billing software modifications Weighted = 0.20 6.40 2(c) 33% Wet Weather Allocation 60/40 CapacityNolume Allocation Updated Wet Weather Flow Percentage Wet Weather Volume and Subsidized Stormwater Cost Allocated Based on Impervious Area 6 Weighted = 1.20 10 - increase equity adding impervious area charge for stormwater costs Weighted = 400 6 Weighted = 1.80 8 - requires impervious area billing software modifications Weighted = 0.80 7.80 Maximum Score 10 10 10 10 Weighting Factors 20% 40% 30% 10% (a) Rate Impact is based on the Standard Deviation of the Average Single Family Residential bill. (b) Class Equity is based on the Average of (Standard Deviation of an Inter Class calculation plus the Standard Deviation Intra Class calculation (weighted per percent of bills)). (c) Rate Impact and Class Equity are based on wastewater revenue for the customer classes evaluated. war- tat ri assri W wad wadi ..sidi imki ii. ril err mil emir o gm loft ham `rllrl lo• Table 4-7 Alternative 2 Minimum 8-Inch-Feet of System Pipe - CapacityNolume Allocation Wastewater Allocation Alternative Evaluation Matrix No. Alternative Description Rate Impact (a) (c) Ratemaking Methodology Class Equity (b) (c) Administrative Simplicity Total Weight 3(a) 33% Wet Weather Allocation 24/76 CapacityNolume Allocation Updated Wet Weather Flow Percentage Wet Weather Volume Cost Allocated Based on Billed Volume 4 Weighted = 0.80 2 - wet weather flow and wet weather cost allocation factors supportable Weighted = 0.80 6.5 Weighted = 1.95 6 - existing rate structure and billing process Weighted = 0.60 4.15 3(b) 33% Wet Weather Allocation 24/76 CapacityNolume Allocation Updated Wet Weather Flow Percentage Wet Weather Volume Cost Allocated Based on Impervious Area 5 Weighted = 1.00 6 - wet weather flow and wet weather cost allocation factors supportable a charge for stormwater costs Weighted = 2.40 5 Weighted = 1.50 2 - requires impervious area billing software modifications Weighted = 0.20 5.10 3(c) 33% Wet Weather Allocation 24/76 CapacityNolume Allocation Updated Wet Weather Flow Percentage Wet Weather Volume and Subsidized Stormwater Cost Allocated Based on Impervious Area 5 Weighted = 1.00 8 - increase equity adding impervious area charge for stormwater costs Weighted = 3.20 5 Weighted = 1.50 6 - requires impervious area billing software modifications Weighted = 0.60 6.30 Maximum Score 10 10 10 10 Weighting Factors 20% 40% 30% 10% (a) Rate Impact is based on the Standard Deviation of the Average Single Family Residential bill. (b) Class Equity is based on the Average of (Standard Deviation of an Inter Class calculation plus the Standard Deviation Intra Class calculation (weighted per percent of bills)). (c) Rate Impact and Class Equity are based on wastewater revenue for the customer class evaluated. 1 1 1 1 t t t t t t t Table 4-8 Summary of We Alternatives Rate Impact Rate Methodology Class Equity Admin Simplicity Total Rank 2 (c) weighted 1.20 4.00 1.80 0.80 7.80 1 1 (c) weighted 1.80 3.20 1.50 0.80 7.30 2 1 (a) weighted 1.60 1.60 2.70 0.80 6.70 3 A weighted 2.00 0.80 3.00 0.80 6.60 4 2 (b) weighted 1.20 3.20 1.80 0.20 6.40 5 3 (c) weighted 1.00 3.20 1.50 0.60 6.30 6 2 (a) weighted 1.40 1.60 2.25 0.80 6.05 7 1 (b) weighted 1.80 2.40 1.50 0.20 5.90 8 3 (b) weighted 1.00 2.40 1.50 0.20 5.10 9 3 (a) weighted 0.80 0.80 1.95 0.60 4.15 10 I 1 A.1 Sewershed Analysis a I i 1 t A sewershed level analysis was performed to demonstrate the variability of wet weather flow on a sub -service area level. The analysis was performed using the 2003 flow monitoring program data. This data was taken from May to September 2003. Five representative sewersheds were selected based on available data, service area, and anticipated I/I contribution. Valid data from the flow meter closest to the downstream end of the sewershed was used in the analysis. In some sewersheds, several meters had to be analyzed to account for all of the flow. Rainfall data from rain gauges set up in conjunction with the 2003 flow monitoring program was used in the analysis. The 15- minute rainfall data from the gauge closest to the flow meter was used. Rainfall and 15- minute flow monitoring data was entered into the SHAPE program. SHAPE decomposes the flow between dry weather and wet weather using selected dry weather hydrographs. The hydrographs used in SHAPE were set by selecting the days when no rainfall had occurred for at least six days. The results of the SHAPE analysis for each watershed are included in Table A-1. Table A-1 Volumetric Comparison for Selected Sewersheds in 2003 Monitoring Period Dry Versus Wet Sewershed Dry Wet Fee Fee Creek 91% 9% Coldwater Creek . 84% 16% Deer Creek 68% 32% Kiefer Creek 95% 5% Mackenzie Creek 80% 20% The percentages in Table A-1 do not include contributions from SSOs because it would require an extensive modeling and calibration effort. SSOs that could be captured for future conveyance and treatment could significantly increase the percentage of wet weather flow in the Fee Fee Creek, Coldwater Creek, and Deer Creek sewersheds, which have 20, 42 and 45 bypasses, respectively. The highest percentage of wet weather flow calculated was in Deer Creek at 32 percent, which is part of the River Des Peres Service Area. This percentage correlates well with Figure A-1 where it is shown that the River Des Peres Service Area had the highest percentage of wet weather flow (not including CSO contribution) at 23 percent. Mackenzie Creek, also part of the River Des Peres Service Area had the next highest wet weather flow percentage at 20 percent. Of the separate areas, Coldwater Creek sewershed, which is part of the Coldwater Creek Service Area, had the highest percent wet weather flow at 16 percent which also corresponds to its highest separate service area wet weather flow percentage at 17 percent (Figure A-1). However, Kiefer Creek sewershed, which is part of the Lower Meramec Service Area, had the lowest wet weather flow percentage at 5 percent. Because the Kiefer Creek sewershed is a newer system with no SSOs, 5 percent is a reasonable estimate of wet weather flow percentage, but is not representative of the A-1 entire Lower Meramec Service Area which had a wet weather flow percentage of 14 percent (Figure A-1). Figure A-1 Dry Weather Flow vs. Wet Weather Flow Percentage by Service Area 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0% *Does not include October 2001 flow data Rainfall volume was compared for each sewershed with the 54-year mean monthly rainfall totals from the Lambert - St. Louis International rain gauge. The results are shown in Figure A-2. The rainfall totals show that in all sewersheds, June 2003 was a wet month compared to the historical mean. The entire flow monitoring period was also wetter than normal compared to the historical mean. The varying rainfall totals at each sewershed also demonstrate the localization of rainfall within the system. A-2 Figure A-2 Monthly Rainfall Totals in Selected Sewersheds Compared to 54-year Mean Monthly Rainfall Total at Lambert -St. Louis International Rain Gauge 25 20 15 = 10 Deer Creek TO 5 .rre o 1-r Joe �Jr1 o,JSti sec �JF PJ �eF �eQ 0 2003 ■ Lambert Airport Mackenzie Creek 25 20 R• 15 Its 5 -AM FAN ,De` 5Ji QJ ms 0 2003 ■ Lambert Airport A-3 1 1 i I I 1 1 t 1 1 Wet weather events were also analyzed for each sewershed. Rainfall data was analyzed using SHAPE which generated event statistics. Five events were analyzed for each sewershed. The results are shown in Table A-2. Coldwater Creek, and Deer Creek had the highest percentage of wet weather flow that passed through their respective flow meter during each event (excluding the <2-month event), ranging from 17 to 46 percent, and 34 to 56 percent, respectively. Excluding an unusual 25-year event (and the <2-month event), Kiefer Creek had the lowest wet weather flow passing through the meter, ranging from 11 to 14 percent. Rainfall Volume (in) Table A-2 Analysis of Wet Weather Events for Selected Subsewersheds Rainfall Duration (hr) Peak Hourly Intensity (inthr) Antecedent Dry Period (days) Fee Fee Creek Return Period % of Wet Weather Flow Passed Through the Flow Meter during the Wet Weather Event 1.22 13.5 0.55 1.8 2-month 17% 1.19 6 0.47 2.8 3-month 23% 3.2 3.82 30 13.5 1.02 1.82 0.4 6.4 0.44 8.75 0.17 15.6 1-year 5-year <2-month 33% 21% 6% Coldwater Creek 1.96 12.25 1.52 0.3 6-month 46% 1.21 8.5 0.76 0.8 2-month 44% 3.05 1.03 13 5 1.15 0.64 6.4 9.5 2-year 2-month 41% 17% 0.7 5.75 0.69 1.2 <2-month 0.3% 1.54 13.25 0.94 0.4 3-month 56% 3.1 12 1.82 6.4 2-year 47% 1.21 6.5 0.74 7.4 2-month 34% 1.83 8.5 1.28 8.1 6-month 38% 0.11 0.75 0.11 1.6 < 2-month 26% Kiefer Creek 0.79 11.5 0.22 3.1 < 2-month 5% 1.38 13.25 0.82 0.4 2-month 14% 2.53 12.5 1.31 6.4 1.9 9.25 0.86 4.0 1-year 9-month 11% 11% 6.21 39.25 1.6 0.4 Mackenzie Creek 25-year 36% 1.54 13.25 0.94 0.4 3-month 49% 3.1 1.21 12 6.5 1.82 0.74 6.4 7.4 2-year 2-month 40% 21% 0.74 18.75 0.27 1.1 <2-month 46% 3.59 13.5 1.9 0.3 2-year 47% A-4 i a t t 1 1 1 1 t t Due to differing intensity, antecedent dry period, duration and rainfall volume of wet weather events, the system response is variable. An example of the variability for each sewershed is shown in Figure A-3. Longer antecedent dry periods seem to have lower percentages of wet weather flow, however rainfall volume and peak intensity also influence the percentage of wet weather flow and the system's response. Figure A-3 Wet Weather Event Analysis for Percentage of Observed Wet Weather Flow vs. Antecedent Dry Period 3▪ 40% o a 30% m r 20% c, 3 10% a 0% Fee Fee Creek ■ ■ 5 10 15 20 Antecedent Dry Period (days) 50% 13o 40% O . 30% c W t 20% 2 c 1096 - 0% Coldwater Creek 2 4 6 8 10 Antecedent Dry Period (days) Kiefer Creek ■ ■ ■ 2 4 6 8 Antecedent Dry Period (days) • 60% • 350% •o LL 40% t 30% 2 20% 10% a- 0% Deer Creek ■ . ■ 2 4 6 8 10 Antecedent Dry Period (days) 60% - 50% 40% 30% 20% 10% 0% Mackenzie Creek r ■ 2 4 6 8 Antecedent Dry Period (days) t A-5 A.2 Data Analysis Limitations Within each service area, wet weather varies for each sewershed. Extensive analyses are required to further define the wet weather variability within each sewershed and is recommended before sewershed corrective actions are initiated. Other limitations include: • SSOs have not been modeled or estimated. SSO contribution could be significant in certain areas with many bypasses. MSD's sewer models could be used to simulate annual SSO volumes. This task could be undertaken to further refine the wet - weather volumes. • The analyses did not include 2004 flow monitoring data. Additional analyses could be performed once 2004 data is available. A.3 Conclusions These analyses demonstrate that wet weather contribution is especially variable between sewersheds. Wet weather response is increasingly variable between rainfall events depending on conditions such as antecedent dry period, peak intensity and rainfall volume. It is important to consider this when evaluating wet weather flow for sewer rates. A detailed flow monitoring data analysis and modeling program for wet weather conditions would be necessary to get an accurate account of wet weather flows and SSOs from separate service areas. A-6 sad and sod mid imi mud mid mad a gird W mid lili mill end — rrr num am Alternative 1(a) Wet Weather Flow Percentage Factors Utilized: Ill Allocation Capacity Volume Customer Description City Residence City Residence City Church Original District Residence Original District Residence Original District Residence Annexed Area Residence Annexed Area Residence Tax Exempt - Annexed Area Tax Exempt - Annexed Area High Rise Commercial High Rise Commercial High Rise Commercial Crestwood Mall - Commercial Chesterfield Mall - Commercial Industrial Alternative 1(a) 33% 37% 63% Imprevious Area 1,833 1,833 21,636 2,790 2,790 2,790 5,412 5,412 19,442 19,442 170,557 170,557 170,557 1,663,820 2,561,271 310,567 Typical Billing Summary Monthly Bill CCF $ 0 $ 2 $ 4 $ 6 $ 8 $ 10 $ 12 $ 14 $ - 25 $ 50 $ 1000 $ 10,000 $ 100,000 $ 10,000 $ 50,000 $ 100,000 Monthly Bill $ 6.07 $ 9.50 $ 12.94 $ 16.37 $ 19.80 $ 23.24 $ 26.67 $ 30.10 $ 48.99 $ 91.90 $ 1,722.70 $ 17,172.33 $ 171,668.65 $ 17,183.68 $ 85,848.71 $ 171,680.00 Combined Bill Existinct Bill Variance $ 6.07 $ 7.30 -16.84% $ 9.50 $ 10.62-10.51% $ 12.94 $ 13.94 -7.19% $ 16.37 $ 17.26 -5.15% $ 19.80 $ 20.58 -3.77% $ 23.24 $ 23.90 -2.77% $ 26.67 $ 27.22 -2.02% $ 30.10 $ 30.54 -1.43% $ 48.99 $ 48.80 0.38% $ 91.90 $ 90.30 1.77% $ 1,722.70 $ 1,667.30 3.32% $ 17,172.33 $ 16,607.30 3.40% $ 171,668.65 $ 166,007.30 3.41% $ 17,183.68 $ 16,618.65 3.40% $ 85,848.71 $ 83,018.65 3.41% $ 171,680.00 $ 166,018.65 3.41% sod and mill mil aid OW NW Ili awl and E MIMI fib NW - - it i♦ Alternative 1(b) Wet Weather Flow Percentage Factors Utilized: Ill Allocation Capacity Volume Customer Description City Residence City Residence City Church Original District Residence Original District Residence Original District Residence Annexed Area Residence Annexed Area Residence Tax Exempt - Annexed Area Tax Exempt - Annexed Area High Rise Commercial High Rise Commercial High Rise Commercial Crestwood Mail - Commercial Chesterfield Mall - Commercial Industrial Alternative 1(b) 33% 37% 63% Imprevious Area 1,833 1,833 21,636 2,790 2,790 2,790 5,412 5,412 19,442 19,442 170,557 170,557 170,557 1,663,820 2,561,271 310,567 Typical Billing Summary Monthly Bill CCF Monthly Bill Combined Bill Existing Bill Variance $ 2.79 0 $ 6.07 $ 8.86 $ 7.30 21.36% $ 2.79 2 $ 8.41 $ 11.20 $ 10.62 5.46% $ 32.91 4 $ 10.75 $ 43.66 $ 13.94 213.23% $ 4.24 6 $ 13.09 $ 17.34 $ 17.26 0.44% $ 4.24 8 $ 15.43 $ 19.68 $ 20.58 -4.39% $ 4.24 10 $ 17.77 $ 22.02 $ 23.90 -7.88% $ 8.23 12 $ 20.11 $ 28.35 $ 27.22 4.14% $ 8.23 14 $ 22.45 $ 30.69 $ 30.54 0.48% $ 29.57 25 $ 35.33 $ 64.90 $ 48.80 32.99% $ 29.57 50 $ 64.58 $ 94.16 $ 90.30 4.27% $ 259.44 1000 $ 1,176.29 $ 1,435.73 $ 1,667.30 -13.89% $ 259.44 10,000 $ 11,708.22 $ 11,967.66 $ 16,607.30 -27.94% $ 259.44 100,000 $ 117,027.55 $ 117,286.99 $ 166,007.30-29.35% $ 2,530.93 10,000 $ 11,719.57 $ 14,250.51 $ 16,618.65 -14.25% $ 3,896.10 50,000 $ 58,528.16 $ 62,424.26 $ 83,018.65 -24.81% $ 472.42 100,000 $ 117,038.90 $ 117,511.32 $ 166,018.65 -29.22% ..�i saimi and mod soma mad alma eori smal eriNNW SSW NNW le./ ome inn WM Alternative 1(c) Wet Weather Flow Percentage Factors Utilized: Ill Allocation Capacity Volume Customer Description City Residence City Residence City Church Original District Residence Original District Residence Original District Residence Annexed Area Residence Annexed Area Residence Tax Exempt - Annexed Area Tax Exempt - Annexed Area High Rise Commercial High Rise Commercial High Rise Commercial Crestwood Mall - Commercial Chesterfield Mall - Commercial Industrial Alternative 1(c) 33% 37% 63% Imprevious Area 1,833 1,833 21,636 2,790 2,790 2,790 5,412 5,412 19,442 19,442 170,557 170,557 170,557 1,663,820 2,561,271 310,567 Typical Billing Summary Monthly Bill $ 3.34 $ 3.34 $ 39.38 $ 5.08 $ 5.08 $ 5.08 $ 9.85 $ 9.85 $ 35.39 $ 35.39 $ 310.45 $ 310.45 $ 310.45 $ 3,028.53 $ 4,662.10 $ 565.30 CCF Monthly Bill 0 $ 5.54 2 $ 7.73 4 $ 9.92 6 $ 12.11 8 $ 14.30 10 $ 16.49 12 $ 18.68 14 $ 20.88 25 $ 32.93 50 $ 60.32 1000 $ 1,101.26 10,000 $ 10,962.78 100,000 $ 109,578.02 10,000 $ 10,974.14 50,000 $ 54,803.13 100,000 $ 109,589.37 Combined Bill Existing Bill Variance $ 8.87 $ 7.30 21.53% $ 11.06 $ 10.62 4.17% $ 49.30 $ 13.94 253.66% $ 17.19 $ 17.26 -0.42% $ 19.38 $ 20.58 -5.83% $ 21.57 $ 23.90 -9.75% $ 28.53 $ 27.22 4.83% $ 30.73 $ 30.54 0.61% $ 68.32 $ 48.80 39.99% $ 95.71 $ 90.30 5.99% $ 1,411.71 $ 1,667.30 -15.33% $ 11,273.24 $ 16,607.30 -32.12% $ 109,888.47 $ 166,007.30 -33.81% $ 14,002.67 $ 16,618.65 -15.74% $ 59,465.23 $ 83,018.65 -28.37% $ 110,154.67 $ 166,018.65 -33.65% ...J =NJ r...ii ...i .rrJ Ewa _ J ..,d road eeeei um! M IMMO I.reO W il■er O Alternative 2(a) Wet Weather Flow Percentage Factors Utilized: Ill Allocation Capacity Volume Customer Description City Residence City Residence City Church Original District Residence Original District Residence Original District Residence Annexed Area Residence Annexed Area Residence Tax Exempt - Annexed Area Tax Exempt - Annexed Area High Rise Commercial High Rise Commercial High Rise Commercial Crestwood Mall - Commercial Chesterfield Mall - Commercial Industrial Alternative 2(a) 33% 60% 40% Imprevious Area 1,833 1,833 21,636 2,790 2,790 2,790 5,412 5,412 19,442 19,442 170,557 170,557 170,557 1,663,820 2,561,271 310,567 Typical Billing Summary Monthly Bill CCF Monthly Bill $ 0 $ $ 2 $ $ 4 $ $ 6 $ $ 8 $ $ 10 $ $ 12 $ $ 14 $ $ 25 $ $ 50 $ $ 1000 $ $ 10,000 $ $ 100,000 $ $ 10,000 $ $ 50,000 $ $ 100,000 $ 9.32 12.35 15.38 18.42 21.45 24.49 27.52 30.56 47.24 85.17 1,526.46 15,180.74 151, 723.55 15,192.09 75, 877.79 151, 734.90 Combined Bill Existing Bill Variance $ 9.32 $ 7.30 27.62% $ 12.35 $ 10.62 16.30% $ 15.38 $ 13.94 10.37% $ 18.42 $ 17.26 6.72% $ 21.45 $ 20.58 4.24% $ 24.49 $ 23.90 2.46% $ 27.52 $ 27.22 1.11% $ 30.56 $ 30.54 0.05% $ 47.24 $ 48.80 -3.19% $ 85.17 $ 90.30 -5.68% $ 1,526.46 $ 1,667.30 -8.45% $ 15,180.74 $ 16,607.30 -8.59% $ 151,723.55 $ 166,007.30 -8.60% $ 15,192.09 $ 16,618.65 -8.58% $ 75,877.79 $ 83,018.65 -8.60% $ 151,734.90 $ 166,018.65 -8.60% a•i mod mama Mini mod Nail reimi Imo ow Imo Imo Warn ions Alternative 2(b) Wet Weather Flow Percentage Factors Utilized: Ill Allocation Capacity Volume Customer Description City Residence City Residence City Church Original District Residence Original District Residence Original District Residence Annexed Area Residence Annexed Area Residence Tax Exempt - Annexed Area Tax Exempt - Annexed Area High Rise Commercial High Rise Commercial High Rise Commercial Crestwood Mall - Commercial Chesterfield Mall - Commercial Industrial Alternative 2(b) 33% 60% 40% lmprevious Area 1,833 1,833 21,636 2,790 2,790 2,790 5,412 5,412 19,442 19,442 170,557 170,557 170,557 1,663,820 2,561,271 310,567 Typical Billing Summary Monthly Bill $ 1.77 $ 1.77 $ 20.90 $ 2.69 $ 2.69 $ 2.69 $ 5.23 $ 5.23 $ 18.78 $ 18.78 $ 164.73 $ 164.73 $ 164.73 $ 1,606.94 $ 2,473.71 $ 299.95 CCF Monthly Bill Combined Bill Existing Bill Variance 0 $ 9.32 $ 11.09 $ 7.30 51.87% 2 $ 11.66 $ 13.43 $ 10.62 26.43% 4 $ 14.00 $ 34.89 $ 13.94 150.31% 6 $ 16.34 $ 19.03 $ 17.26 10.27% 8 $ 18.68 $ 21.37 $ 20.58 3.85% 10 $ 21.02 $ 23.71 $ 23.90 -0.78% 12 $ 23.36 $ 28.59 $ 27.22 5.02% 14 $ 25.70 $ 30.93 $ 30.54 1.27% 25 $ 38.57 $ 57.35 $ 48.80 17.52% 50 $ 67.83 $ 86.60 $ 90.30 -4.09% 1000 $ 1,179.53 $ 1,344.26 $ 1,667.30 -19.38% 10,000 $ 11,711.46 $ 11,876.19 $ 16,607.30 -28.49% 100,000 $ 117,030.78 $ 117,195.51 $ 166,007.30 -29.40% 10,000 $ 11,722.82 $ 13,329.76 $ 16,618.65 -19.79% 50,000 $ 58,531.40 $ 61,005.12 $ 83,018.65 -26.52% 100,000 $ 117,042.14 $ 117,342.09 $ 166,018.65 -29.32% anal sommi smi a mat w mai >✓ ummil - mod =I-INNOr Um s um Alternative 2(c) Wet Weather Flow Percentage Factors Utilized: Ill Allocation Capacity Volume Customer Description City Residence City Residence City Church Original District Residence Original District Residence Original District Residence Annexed Area Residence Annexed Area Residence Tax Exempt - Annexed Area Tax Exempt - Annexed Area High Rise Commercial High Rise Commercial High Rise Commercial Crestwood Mall - Commercial Chesterfield Mail - Commercial Industrial Alternative 2(c) 33% 60% 40% imprevious Area 1,833 1,833 21,636 2,790 2,790 2,790 5,412 5,412 19,442 19,442 170,557 170,557 170,557 1,663,820 2,561,271 310,567 Typical Billing Summary Monthly Bill $ 2.42 $ 2.42 $ 28.60 $ 3.69 $ 3.69 $ 3.69 $ 7.15 $ 7.15 $ 25.70 $ 25.70 $ 225.46 $ 225.46 $ 225.46 $ 2,199.38 $ 3,385.70 $ 410.53 CCF Monthly Bill Combined Bill Existing Bill Variance 0 $ 8.45 2 $ 10.64 4 $ 12.83 6 $ 15.02 8 $ 17.21 10 $ 19.40 12 $ 21.60 14 $ 23.79 25 $ 35.84 50 $ 63.23 1000 $ 1,104.17 10,000 $ 10,965.69 100,000 $ 109,580.92 10,000 $ 10,977.05 50,000 $ 54,806.04 100,000 $ 109,592.27 $ 10.87 $ 7.30 48.91% $ 13.06 $ 10.62 22.99% $ 41.43 $ 13.94 197.21% $ 18.71 $ 17.26 8.40% $ 20.90 $ 20.58 1.56% $ 23.09 $ 23.90 -3.38% $ 28.75 $ 27.22 5.62% $ 30.94 $ 30.54 1.31% $ 61.54 $ 48.80 26.11 $ 88.93 $ 90.30 -1.51% $ 1,329.63 $ 1,667.30-20.25% $ 11,191.15 $ 16,607.30 -32.61% $ 109,806.37 $ 166,007.30 -33.85% $ 13,176.43 $ 16,618.65 -20.71% $ 58,191.74 $ 83,018.65 -29.91% $ 110,002.81 $ 166,018.65 -33.74% .sue MIA ■J mod NNW mai mil — ..r am — Nis Alternative 3(a) Wet Weather Flow Percentage Factors Utilized: Ill Allocation Capacity Volume Customer Description City Residence City Residence City Church Original District Residence Original District Residence Original District Residence Annexed Area Residence Annexed Area Residence Tax Exempt - Annexed Area Tax Exempt - Annexed Area High Rise Commercial High Rise Commercial High Rise Commercial Crestwood Mall - Commercial Chesterfield Mall - Commercial Industrial Alternative 3(a) 33% 24% 76% Imprevious Area 1,833 1,833 21,636 2,790 2,790 2,790 5,412 5,412 19,442 19,442 170,557 170,557 170,557 1,663,820 2,561,271 310,567 Typical Billing Summary Monthly Bill CCF Monthly Bill Combined Bill Existing Bill Variance $ 0 $ 4.24 $ 4.24 $ 7.30 -41.97% $ - 2 $ 7.90 $ 7.90 $ 10.62 -25.66% $ 4 $ 11.55 $ 11.55 $ 13.94 -17.12% $ 6 $ 15.21 $ 15.21 $ 17.26 -11.86% $ 8 $ 18.87 $ 18.87 $ 20.58 -8.30% $ 10 $ 22.53 $ 22.53 $ 23.90 -5.73% $ 12 $ 26.19 $ 26.19 $ 27.22 -3.79% $ 14 $ 29.85 $ 29.85 $ 30.54 -2.27% $ - 25 $ 49.97 $ 49.97 $ 48.80 2.40% $ 50 $ 95.71 $ 95.71 $ 90.30 5.99% $ 1000 $ 1,833.61 $ 1,833.61 $ 1,667.30 9.98% $ 10,000 $ 18,298.01 $ 18,298.01 $ 16,607.30 10.18% $ 100,000 $ 182,941.96 $ 182,941.96 $ 166,007.30 10.20% $ 10,000 $ 18,309.36 $ 18,309.36 $ 16,618.65 10.17% $ 50,000 $ 91,484.45 $ 91,484.45 $ 83,018.65 10.20% $ 100,000 $ 182,953.31 $ 182,953.31 $ 166,018.65 10.20% ommi somil mad ma mod semi NNW owl mil mosi nog loosi IN= 11•0 MN UM Alternative 3(b) Wet Weather Flow Percentage Factors Utilized: Ill Allocation Capacity Volume Customer Description City Residence City Residence City Church Original District Residence Original District Residence Original District Residence Annexed Area Residence Annexed Area Residence Tax Exempt - Annexed Area Tax Exempt - Annexed Area High Rise Commercial High Rise Commercial High Rise Commercial Crestwood Mall - Commercial Chesterfield Mall - Commercial Industrial Alternative 3(b) 33% 24% 76% Imprevious Area 1,833 1,833 21,636 2,790 2,790 2,790 5,412 5,412 19,442 19,442 170,557 170,557 170,557 1,663,820 2,561,271 310,567 Typical Billing Summary Monthly Bill $ 3.36 $ 3.36 $ 39.70 $ 5.12 $ 5.12 $ 5.12 $ 9.93 $ 9.93 $ 35.68 $ 35.68 $ 312.98 $ 312.98 $ 312.98 $ 3,053.19 $ 4,700.06 $ 569.91 CCF Monthly Bill Combined Bill Existing Bill Variance 0 $ 4.24 $ 7.60 $ 7.30 4.11% 2 $ 6.58 $ 9.94 $ 10.62 -6.40% 4 $ 8.92 $ 48.62 $ 13.94 248.78% 6 $ 11.26 $ 16.38 $ 17.26 -5.11% 8 $ 13.60 $ 18.72 $ 20.58 -9.05% 10 $ 15.94 $ 21.06 $ 23.90 -11.89% 12 $ 18.28 $ 28.21 $ 27.22 3.64% 14 $ 20.62 $ 30.55 $ 30.54 0.04% 25 $ 33.49 $ 69.17 $ 48.80 41.74% 50 $ 62.75 $ 98.42 $ 90.30 9.00% 1000 $ 1,174.45 $ 1,487.43 $ 1,667.30 -10.79% 10,000 $ 11,706.38 $ 12,019.36 $ 16,607.30 -27.63% 100,000 $ 117,025.68 $ 117,338.66 $ 166,007.30 -29.32% 10,000 - $ 11,717.74 $ 14,770.93 $ 16,618.65 -11.12% 50,000 $ 58,526.31 $ 63,226.37 $ 83,018.65 -23.84% 100,000 $ 117,037.04 $ 117,606.94 $ 166,018.65 -29.16% and Nummil ma mod mid mad ma end sod mai nod mod Immi NNW =NI ono mow Nom Alternative 3(c Wet Weather Flow Percentage Factors Utilized: Alternative 3(c) Ill Allocation 33% Capacity 24% Volume 76% Typical Billing Summary Imprevious Customer Description Area Monthly Bill CCF Monthly Bill Combined Bill Existing Bill Variance City Residence 1,833 $ 3.85 0 $ 3.89 $ 7.74 $ 7.30 6.05% City Residence 1,833 $ 3.85 2 $ 6.08 $ 9.93 $ 10.62 -6.47% City Church 21,636 $ 45.48 4 $ 8.27 $ 53.75 $ 13.94 285.57% Original District Residence 2,790 $ 5.86 6 $ 10.46 $ 16.33 $ 17.26 -5.40% Original District Residence 2,790 $ 5.86 8 $ 12.65 $ 18.52 $ 20.58 -10.01% Original District Residence 2,790 $ 5.86 10 $ 14.85 $ 20.71 $ 23.90 -13.35% Annexed Area Residence 5,412 $ 11.38 12 $ 17.04 $ 28.41 $ 27.22 4.38% Annexed Area Residence 5,412 $ 11.38 14 $ 19.23 $ 30.60 $ 30.54 0.21% Tax Exempt - Annexed Area 19,442 $ 40.87 25 $ 31.28 $ 72.15 $ 48.80 47.84% Tax Exempt - Annexed Area 19,442 $ 40.87 50 $ 58.68 $ 99.54 $ 90.30 10.23% High Rise Commercial 170,557 $ 358.49 1000 $ 1,099.61 $ 1,458.11 $ 1,667.30 -12.55% High Rise Commercial 170,557 $ 358.49 10,000 $ 10,961.13 $ 11,319.63 $ 16,607.30 -31.84% High Rise Commercial 170,557 $ 358.49 100,000 $ 109,576.34 $ 109,934.84 $ 166,007.30 -33.78% Crestwood Mall - Commercial 1,663,820 $ 3,497.19 10,000 $ 10,972.49 $ 14,469.67 $ 16,618.65 -12.93% Chesterfield Mall - Commercial 2,561,271 $ 5,383.54 50,000 $ 54,801.47 $ 60,185.01 $ 83,018.65 -27.50% Industrial 310,567 $ 652.78 100,000 $ 109,587.69 $ 110,240.48 $ 166,018.65 -33.60% aid owel coal gasimJ gel wool _ Table C-1 Standard Deviation Calculations 1. Inter -Class 1a 1b lc 2a 2b 2c 3a 3b 3c Single Family -0.61 -0.31 -0.31 0.86 1.05 1.05 -1.44 -1.08 -1.08 Multi Family 0.83 -6.72 -6.72 -1.48 -6.27 -6.27 2.13 -6.98 -6.98 Non -Residential All Other 7.1 16.01 16.01 -9.42 -3.76 -3.76 16.44 27.19 27.19 1. Standard Deviation 4.099 11.720 11.720 5.388 3.720 3.720 9.462 18.265 18.265 Score (10 highest) 9.00 5.00 5.00 7.00 8.00 8.00 6.00 4.00 4.00 2. Intra-Class Single Family City Residence - 0 ccf -1.16 1.34 1.34 1.75 3.34 3.34 -2.8 0.21 0.21 City Residence - 2 ccf -1.03 0.49 0.49 1.53 2.49 2.49 -2.47 -0.64 -0.64 City Residence - 4 ccf -0.89 -0.35 -0.35 1.3 1.64 1.64 -2.13 -1.48 -1.48 Original D. Res. - 6 ccf -0.75 0.11 0.11 1.09 1.63 1.63 -1.79 -0.75 -0.75 Original D. Res. - 8 ccf -0.62 -0.73 -0.73 0.86 0.79 0.79 -1.45 -1.59 -1.59 Original D. Res. - 10 ccf -0.48 -1.57 -1.57 0.65 -0.05 -0.05 -1.11 -2.43 -2.43 Annexed Area Res - 12 ccf -0.34 1.16 1.16 0.42 1.37 1.37 -0.78 1.04 1.04 Annexed Area Res - 14 ccf -0.2 0.32 0.32 0.2 0.54 0.54 -0.43 0.2 0.2 2.a. Standard Deviation -Single Family 0.336 0.967 0.967 0.542 1.085 1.085 0.829 1.138 1.138 Multi Family 0 0 0 0 0 0 0 0 0 2.b. Standard Deviation - Multi -Family 0.83 -6.72 -6.72 -1.48 -6.27 -6.27 2.13 -6.98 -6.98 Standard Deviation 0.587 4.752 4.752 1.047 4.434 4.434 1.506 4.936 4.936 Non -Residential All Other Tax Exempt - Annexed Area - 25 ccf 0.55 14.82 14.82 -1.01 8.05 8.05 1.43 18.64 18.64 Tax Exempt - Annexed Area - 50 ccf 2.27 4.29 4.29 -3.77 -2.48 -2.48 5.68 8.11 8.11 High Rise Commercial - 1000 ccf 67.32 -189.96 -189.96 -108.62 -271.97 -271.97 166.77 -143.61 -143.61 2.c. Standard Deviation Non -Res 38.063 115.310 115.310 61.347 158.717 158.717 94.256 90.788 90.788 2.a. b. c. Standard Deviation - Weighted 2.615 8.186 8.186 4.224 10.843 10.843 6.477 6.884 6.884 Score (10 highest) 9.00 5.00 5.00 8.00 4.00 4.00 7.00 6.00 6.00 3. Class Equity - Average of 1 and 2 9.00 5.00 5.00 7.50 6.00 6.00 6.50 5.00 5.00 4. Rate Impact Single Family Residential Bills Variance 1a 1b 1c 2a 2b 2c 3a 3b 3c 0 0 0 0 0 0 0 0 0 Single Family -0.61 -0.31 -0.31 0.86 1.05 1.05 -1.44 -1.08 -1.08 Standard Deviation 0.431 0.219 0.219 0.608 0.742 0.742 1.018 0.764 0.764 Score (10 highest) 8.00 9.00 9.00 7.00 6.00 6.00 4.00 5.00 5.00 Table C-2 Summary of Weighted Scores Rate Admin Rate Impact Methodology Class Equity Simplicity Total A 10 2 10 8 A weighted 2.00 0.80 3.00 0.80 6.60 1 (a) 8 4 9 8 1 (a) weighted 1.60 1.60 2.70 0.80 6.70 1 (b) 9 6 5 2 1 (b) weighted 1.80 2.40 1.50 0.20 5.90 1 (c) 9 8 5 8 1 (c) weighted 1.80 3.20 1.50 0.80 7.30 2 (a) 7 4 7.5 8 2 (a) weighted 1.40 1.60 2.25 0.80 6.05 2 (b) 6 8 6 2 2 (b) weighted 1.20 3.20 1.80 0.20 6.40 2 (c) 6 10 6 8 2 (c) weighted 1.20 4.00 1.80 0.80 7.80 3 (a) 4 2 6.5 6 3 (a) weighted 0.80 0.80 1.95 0.60 4.15 3 (b) 5 6 5 2 3 (b) weighted 1.00 2.40 1.50 0.20 5.10 3 (c) 5 8 5 6 3 (c) weighted 1.00 3.20 1.50 0.60 6.30 Max Point Score 10 10 10 10 Weight Factors 20% 40% 30% 10% 100% Max Weighted Score 2.00 4.00 3.00 1.00 10.00 Table C-3 Summary of Weighted Alternatives 1 1 1 i t t t t Alternatives Rate Impact Rate Methodology Class Equity Admin Simplicity Total Rank 2 (c) weighted 1.20 4.00 1.80 0.80 7.80 1 1 (c) weighted 1.80 3.20 1.50 0.80 7.30 2 1 (a) weighted 1.60 1.60 2.70 0.80 6.70 3 A weighted 2.00 0.80 3.00 0.80 6.60 4 2 (b) weighted 1.20 3.20 1.80 0.20 6.40 5 3 (c) weighted 1.00 3.20 1.50 0.60 6.30 6 2 (a) weighted 1.40 1.60 2.25 0.80 6.05 7 1 (b) weighted 1.80 2.40 1.50 0.20 5.90 8 3 (b) weighted 1.00 2.40 1.50 0.20 5.10 9 3 (a) weighted 0.80 0.80 1.95 0.60 4.15 10 Table C-4 Billable Units of Service Related to Functional Cost Elements H-11 Table Ref. Percent Customer H-5 Customer Related H-5 Volume Related H-5 45% of Total Treated I/1 Capacity I/I 37% 25,353,900 43,170,100 37% 291,049 495,570 68,524,000 786,619 (4.19 times I/I volume/365) H-5 Total Treated 152,275,600 H-7 Volume Related Capacity H-7 Total Capacity Percent Customer Customer Related Volume Related 396,960 (1.73 times contrib. volume/365) 1,183,579 BOD I/I TSS Ill 37% 3,955,226 6,734,574 37% 7,910,415 13,469,085 H-6 Normal Loading x I/I Vol. 10,689,800 21,379,500 H-6 Normal Loading x Contrib Vol 107,135,000 112,361,100 B-9 & H-6 Extra Strength 24,600,000 19,150,400 Total Loadings 142,424,800 152,891,000 1 Table C-5 1 1 i 1 1 1 1 i 1 a 1 t 1 Calculation of Unit Costs -Revised Existing A Less: Stormwater Table H-9 ccf/day Cost/ccf System Availability Charge Customer Related Cap. I/1 Balance of Costs Equivalent Bills System Availability Charge - $/Bill Volume Charqe Volume Related Capacity Volume Related I/I Capacity Balance of Costs Equivalent Billable Volume - ccf Capacity Cost - Revised Capacity Cost - Existing $118,012,400 (13,657,600) $104,354,800 1,183,579 $118,012,400 1,183,579 $88.16885 $99.70809 Revised Cost Existing Cost 291,049 88.16885 $25,661,458 $29,019,943 4,343,833 4,343,833 396,960 88.16885 495,570 88.16885 Difference ($3,358,484) $30,005,291 $33,363,776 ($3,358,484) 5,134,082 5,134,082 $5.84433 $6.49849 $34,999,507 43,693,835 48,085,335 $39,580,123 ($4,580,616) 49,412,335 (5,718,500) 48,085,335 $126,778,677 $137,077,792 83,527,350 83,527,350 $1.51781 $1.64111 ($13,657,600) 1 1 Table C-6 I Table H-5 fable H-5 ,Table H-5 tingle Family Multi -Family !Ion -Residential Revisions per Customer Class - Existing A Bills Volume Single Family 4,291,185 34,473,150 Multi -Family 534,925 15,597,100 Non -Residential 307,972 33,457,100 5,134,082 83,527,350 Billing Charge Avail. Charge $1.13557 $5.84440 Volume Charge Extra S. Compliance $11.35375 Total Bills New $82,276,379 4,291,185 $19.17 $607,445 $3,126,316 $23,673,590 $27,407,351 534,925 $51.24 $349,724 $1,799,912 $50,781,856 $6,571,687 $3,496,637 $62,999,815 307,972 $204.56 $5,830,109 $30,005,629 $126,779,482 $6,571,687 $3,496,637 $172,683,545 allocated Costs $5,830,100 $30,005,300 $126,778,716 $6,571,687 $3,496,500 $172,682,303 $4,872,941 $25,079,402 $1.5178 $52,324,037 I I Table H-5 Single Family able H-5 Multi -Family table H-5 'tingle Family Multi -Family lon-Residential Lflocated Cost Non -Residential Revisions per Customer Class - 1(a) Bills Volume 4,291,185 534,925 307,972 Table C-7 34,473,150 15,597,100 33,457,100 5,134,082 83,527,350 Billing Charge Avail. Charge Volume Charge Extra S. Compliance Total Bills New $1.13557 $4,872,941 $4.68087 $20,086,479 $607,445 $2,503,914 $349,724 $1,441,577 $5,830,109 $24,031,970 $5,830,100 $24,031,977 $1.58630 $54,684,758 $24,741,680 $53,072,998 $132,499,435 $132,499,510 $6,824,212 $6,824,212 $6,824,212 $11.35375 $3,496,637 $3,496,637 $3,496,500 $79,644,178 $27,853,039 $65,185,147 $172,682,364 $172,682,299 4,291,185 534,925 307,972 $18.56 $52.07 $211.66 Table C-8 I Revisions per Customer Class -1(b) and 1(c) Bills Volume Imp Area Table H-5 Single Family 4,291,185 34,473,150 1,111,065,766 able H-5 Multi -Family 534,925 15,597,100 220,046,834 Table H-5 Non -Residential 307,972 33,457,100 5,134,082 83,527,350 2,500,300,811 IBilling Charge I Avail. Charge J Volume Charge I Extra S. I Compliance I Imp Area I Total I Bills I New $1.13557 $4.68087 $1.09641 $11.35375 $0.016366 Single Family $4,872,941 $20,086,479 $37,796,706 18,183,702 $80,939,829 4,291,185 $18.86 tulti-Family $607,445 $2,503,914 $17,100,816 3,601,286 $23,813,462 534,925 $44.52 Non -Residential $349,724 $1,441,577 $36,682,699 $6,824,212 $3,496,637 19,134,934 $67,929,783 307,972 $220.57 II$5,830,109 $24,031,970 $91,580,222 $6,824,212 $3,496,637 $40,919,923 $172,683,074 Allocated Cost $5,830,100 $24,031,977 $91,580,197 $6,824,212 $3,496,500 $40,919,313 $172,682,299 1,169,188,211 t t i i t t i t I I Table H-5 fable H-5 Multi -Family Table H-5 tingle Family Multi -Family Ion -Residential Revisions per Customer Class - 2(a) Bills Volume Single Family Non -Residential 4,291,185 534,925 307,972 Table C-9 34,473,150 15,597,100 33,457,100 5,134,082 83,527,350 Billing Charge $1.13557 $4,872,941 Avail. Charge $7.5906 $32,572,669 $607,445 $4,060,402 $349,724 $2,337,692 $5,830,109 $38,970,763 allocated Cost $5,830,100 $38,970,773 i 1 1 1 i 1 1 1 1 I 1 Volume Charge $1.41 $48,519,235 $21,952,138 $47,089,195 $117,560,569 $117,560,713 Extra S. I Compliance $6,824,212 $6,824,212 $6,824,212 $11.35375 $3,496,637 $3,496,637 $3,496,500 Total $85,964,845 $26,619,985 $60,097,461 $172,682,290 $172,682,298 Bills 4,291,185 534,925 307,972 New $20.03 $49.76 $195.14 Table C-10 I Table H-5 ITable H-5 Table H-5 I Single Family 'Multi -Family Non -Residential I Allocated Cost I 1 1 i i t t t 1 Revisions per Customer Class - 2(b) and 2(c) Bills Volume Single Family 4,291,185 34,473,150 Multi -Family Non -Residential I Billing Charge I $1.13557 $4,872,941 $607,445 $349,724 $5,830,109 $5,830,100 534,925 15,597,100 Imp Area 1,111,065,766 220,046,834 307,972 33,457,100 I 1,169,188,211 5,134,082 83,527,350 2,500,300,811 Avail. Charge I Volume Charge I $7.5906 $32,572,669 $4,060,402 $2,337,692 $38,970,763 $38,970,773 $1.09641 $37,796,706 $17,100,816 $36,682,699 $91,580,222 $91,580,197 Extra S. I Compliance I Imp Area I Total $6,824,212 $6,824,212 $6,824,212 S11.35375 $3,496,637 $3,496,637 $3,496,500 $0.010391 11,545,084 2,286,507 12,149,035 $25,980,626 $25,980,516 $86,787,401 $24,055,170 $61,839,999 $172,682,569 $172,682,298 Bills 4,291,185 534,925 307,972 New $20.22 $44.97 $200.80 1 Table C-11 I Revisions per Customer Class - 3(a) Bills Volume Table H-5 Single Family 4,291,185 34,473,150 'able H-5 Multi -Family 534,925 15,597,100 Table H-5 Non -Residential 307,972 33,457,100 1 Billing Charge $1.13557 $3.0362 $1.69 $11.35375 tingle Family $4,872,941 $13,029,068 $58,169,649 $76,071,657 4,291,185 $17.73 Multi -Family $607,445 $1,624,161 $26,318,391 $28,549,996 534,925 $53.37 Ilion -Residential $349,724 $935,077 $56,455,176 $6,824,218 $3,496,637 $68,060,832 307,972 $221.00 $5,830,109 $15,588,305 $140,943,215 $6,824,218 $3,496,637 $172,682,485 allocated Cost $5,830,100 $15,588,303 $140,943,179 $6,824,212 $3,496,500 $172,682,294 5,134,082 83,527,350 Avail. Charge Volume Charge Extra S. Compliance Total Bills New Table C-12 I Table H-5 able H-5 able H-5 Revisions per Customer Class - 3(b) and 3(c) Bills Volume Imp Area Single Family 4,291,185 34,473,150 1,111,065,766 Multi -Family 534,925 15,597,100 220,046,834 307,972 33,457,100 5,134,082 83,527,350 2,500,300,811 IBilling Charge J Avail. Charge I Volume Charge I Extra S. I Compliance I Imp Area I Total I Bills I New $1.13557 $3.0362 $1.09641 $11.35375 $0.019743 Single Family $4,872,941 $13,029,068 $37,796,706 21,935,771 $77,634,486 4,291,185 $18.09 ltult.F8milY $607,445 $1,624,161 $17,100,816 4,344,385 $23,676,807 534,925 $44.26 Non -Residential $349,724 $935,077 $36,682,699 $6,824,218 $3,496,637 23,083,283 $71,371,638 307,972 $231.75 I$5,830,109 $15,588,305 $91,580,222 $6,824,218 $3,496,637 $49,363,439 $172,682,930 Allocated Cost $5,830,100 $15,588,303 $91,580,220 $6,824,218 $3,496,500 $49,362,958 $172,682,299 1,169,188,211 1 1 1 1 1 1 1 1 1 1 1 1 1 Non -Residential t 1 1 i 1 i t t t i Appendix D Glossary Average Annual Flow - The flow volume over a calendar year based on an averaging of a single or multiple 365 day period. Ccf - Volume measurement equal to 100 cubic feet (748-gallons) of wastewater. Combined Sewer Overflow (CSO) - Flow from combined sewer system, in excess of sewer capacity, that is discharged to a waterbody without treatment. Combined Sewer System - Combined sewer systems are sewers that are designed to collect rainwater runoff, domestic sewage, and industrial wastewater in the same pipe. Dry Weather Flow - Non -storm flow that consists of the average sewage flow and average dry weather infiltration/inflow. Equivalent Length (inch -feet of pipe) - A means of calculating pipe equivalency by multiplying the pipe diameter by the length of pipe. Impervious Area - Impermeable surfaces, such as pavement or rooftops, which impede natural infiltration of water to the soil. Infiltration/Inflow (I/I) - Infiltration is water that enters sewer pipes through cracks and joints. Also, the movement of water downward from the ground surface through the upper soil. Inflow is surface water entering the sanitary sewer system through illicit connections, roof drains, open or defective manholes, etc. Sanitary Sewer System - A sanitary sewer system is a wastewater collection system, owned by a state or municipality, that is specifically designed to collect and convey only sanitary wastewater (domestic sewage from homes as well as industrial and commercial wastewater). Sanitary Sewer Overflow (SSO) - Discharge of sewage from a separate sewer system when the collection system capacity is exceeded due to wet weather (as the result of infiltration and inflow), when normal dry weather flow is blocked for any of several reasons, or when mechanical failures prevent the system from proper operation. Separate Sewer System -A sewer system and drains in which sanitary wastewater and storm water are carried in different conduits. Sf - Measurement of the total impervious area by square feet. Surface Runoff - Rainfall dependent flow over the surface, after infiltration, interception, and surface storage occurred. System Availability Charge - is a charge per the equivalent number of bills used to recover customer related Inflow/Infiltration costs. Volume Recovery Charge - is a charge per hundred cubic feet (Ccf) used to recover volume related costs. D-1 Wet Weather Flow - In a separate sewer system, wet weather flow is a combination of dry weather flow, inflow and infiltration which occurs as a result of rain and storms. In a combined sewer system, wet weather flow is a combination of dry weather flow, surface runoff captured by the sewer system, and infiltration. D-2 1 i