CSO 217/483 Source Control Phase B

Transcription

1 CSO 217/483 Source Control Phase B Alternative Analysis Report DRAFT Prepared by POWER Engineers, Inc. PID # Draft Revision B - Briefing Review October 3, 2014

2 Table of Contents CSO 217/483 Source Control Phase B Executive Summary 2.0 The Problem 2.1 Problem Statement 2.2 Condition Assessment 2.3 Problem Diagnosis 3.0 Project Objectives 3.1 The Big Picture 3.2 Project Objectives Project Objectives Established Prior to the Planning Effort Project Objectives Established During the Planning Effort Unique Project Constraints, Influences, or Issues affecting the Project 3.3 Boundary of the Analysis 3.4 Project Coordination MSDGC Project Dependencies and Coordination Requirements Intergovernmental Coordination Requirements 4.0 Strategies 4.1 Strategy Development and Initial Screening 4.2 Analysis of the Strategies 5.0 Alternatives 5.1 Alternative Development Methodology 5.2 Alternative Analysis Methodology 5.3 Alternatives 5.4 Summary Comparison of Alternatives 5.5 Recommendation 6.0 Execution Plan 6.1 Budget Cost Estimate Legislative History Proposed Legislation & Funding Sources 6.2 Schedule 6.3 Scope Summary of Project Scope Functional Requirements and Design Basis Work Performed in Planning/Anticipated Work in Design 6.4 Roles and Responsibilities 6.5 Project Risks 7.0 Major References Appendix A Appendix B Appendix C Appendix D Appendix E Opinion of Probable Cost, Environmental and Social Impact Analysis, and Risk Register Conceptual Alternatives Design Plans CSO 217 Storage Tank Alternative Analysis Technical Memorandum Geomorphic Assessment and Conceptual Alternatives Memorandum (Kings Run) Kings Run Stream Survey and Flow Monitoring and Modeling Memorandum DRAFT 10/03/2014

3 Section 1 Executive Summary CSO 217/483 Source Control Phase B 3 Why: A 1.5 MG CSO storage tank is a component of the Kings Run Separation and Wooden Shoe Storage project under the approved Revised Original Lower Mill Creek Partial Remedy (LMCPR). The purpose of this storage tank is to achieve CSO volume control at CSO 217, in concert with three proposed upstream detention basins, as agreed upon under the Revised Original LMCPR. Stream bank stabilization and restoration measures to Kings Run downstream of CSO 217 are also included as a component of the Kings Run project under the approved Revised Original LMCPR to improve the stream condition after implementation of upstream source control measures. What: The alternative recommended approach is the following: Construct a 1.5 MG CSO storage tank of circular, in-ground concrete construction, and with gravityin/gravity-out flow control and other appurtenances at the location of existing CSO 217 Construct stream stabilization improvements in the current alignment of Kings Run, downstream of the proposed CSO storage tank, including grade control structures, bank re-grading, bank toe and surface stabilization, benchfull wetlands, and restoration of riparian vegetation Where: The CSO 217/483 Source Control Phase B area is CSO 217 and the Kings Run surface stream from CSO 217 to where it is intercepted by an existing 14-foot by 8-foot combined sewer at Kings Run Drive and Winton Ridge Lane. This project area is located within the CSO 483 drainage area, in Wooden Shoe Hollow, between Winton Road and Winton Ridge Lane, in the Winton Hills neighborhood of Cincinnati (see Figure 1). How: The Total Opinion of Project Cost associated with the implementation of the recommended sustainable infrastructure is approximately 19 million in 2018 dollars (14.2 million in 2006). If approved, project funding would need to be legislated through Hamilton County. When The Schedule of the Project is 4.0 years, from Design through Construction. The project must be constructed by 12/31/2018. DRAFT 10/03/2014

4 Section 2 The Problem CSO 217/483 Source Control Phase B 4 Section 2.1 Problem Statement MSDGC is under a federal Consent Decree to reduce combined sewer overflows. The approved Revised Original Lower Mill Creek Partial Remedy (LMCPR) proposes to reduce CSO volume to Mill Creek by 1.78 BG by The Kings Run Separation and Wooden Shoe Storage project is one component of the Revised Original LMCPR. The Kings Run Project will reduce overflows at CSOs 217 and 483 through strategic sewer separation, stormwater detention, and combined flow storage. The project consists of three phases (A, B, and C) that will be constructed between 2015 and Because proposed detention basins (under Phase A) and sewer separation (under Phase C) upstream of CSO 217 do not by themselves achieve the LMCPR Alternative goal for CSO 217, a CSO storage tank is the recommended solution to achieve the LMCPR Alternative goal for CSO 217 under Phase B. The upstream end of Kings Run currently receives flow nearly exclusively from the combined sewer outfall at CSO 217. The flow regime has been altered so that base flow has been effectively eliminated and high flows are extreme. Stream improvements to Kings Run downstream of CSO 217 are recommended to be included under Phase B. Combined sewer overflows represent a failure mode involving Public Health and Safety, and are a problem which is tied to the Wet Weather plan. Stream instability reveals an opportunity to promote channel stability, aquatic habitat, water quality and the aesthetic character of Kings Run; instability also represents the risk of future channel incision exposing the existing combined sewer underlying the stream. A CSO storage tank and stream stabilization have already been approved as components of the Revised Original LMCPR to address Wet Weather Improvement Plan (WWIP) compliance. This Alternative Analysis Report (AAR) is intended to compare and evaluate specifically what type of tank and stream improvements should be installed. Section 2.2 Condition Assessment The problem is driven primarily by Consent Decree requirements to mitigate combined sewer overflows and to a lesser extent by conditions of the existing assets and the receiving water body. This section describes the pertinent existing conditions. Approximately 500 acres of the Kings Run Sub-watershed drain to CSO 217, located on the east side of Winton Road, south of Dutch Colony Drive. CSO 217 discharges to the upstream end of what remains of Kings Run stream. The underflow pipe from CSO 217 parallels the surface stream until both the surface channel and the underflow pipe are re-intercepted downstream by an existing 14 x8 combined sewer. The 14 x8 sewer follows Kings Run Drive until it reaches CSO 483, where overflow from CSO 483 discharges to Mill Creek, and the underflow is sent to treatment TV inspection reports indicate that the underflow piping from CSO 217 is generally in good condition with no repairs needed. The Kings Run Relief Sewer No was constructed circa Access to the existing CSO 217 regulator is via a steep, narrow access drive with a confined ingress/egress arrangement from northbound Winton Road. DRAFT 10/03/2014

5 CSO 217/483 Source Control Phase B 5 Stream erosion is evident throughout Kings Run, and is observed to be more pronounced upstream. A plunge pool has developed at the existing 90-inch diameter combined sewer outfall, formed by displaced rock channel protection. Community involvement activities led to the receipt of input from nearby residents regarding conditions of the stream. Residents have indicated that stream erosion and CSO odor problems have not been addressed. Section 2.3 Problem Diagnosis As stated previously, this project is driven more by regulatory compliance rather than by problems. The necessity of mitigating CSO volume towards WWIP goals requires no additional diagnosis. The existing stream flow regime in Kings Run is not conducive to a healthy aquatic ecosystem, and its flashiness has likely exacerbated stream channel instability. Kings Run is located entirely on private property in the project area, and multiple property owners are each responsible for maintaining their own portion of the stream. The sustainable strategic separation source control approach of the Revised Original LMCPR includes restoration of existing streams to support new storm sewers and stormwater detention basins to control CSOs and to promote water quality. DRAFT 10/03/2014

6 CSO 217/483 Source Control Phase B 6 Figure 1. Project Vicinity Map DRAFT 10/03/2014

7 Section 3 Project Objectives CSO 217/483 Source Control Phase B 7 Section 3.1 The Big Picture The alternatives under evaluation in this AAR are influenced by the results and/or requirements of the following documents: WWIP Requirements The proposed 1.5 MG CSO storage tank at CSO 217 is a Phase 1 project and a component of the Revised Original Lower Mill Creek Partial Remedy (LMCPR). The Revised Original LMCPR estimates that the combined CSO reduction from the Kings Run Sub-basin (both CSO 217 and CSO 483) to Mill Creek to be 156 MG. Because CSO volume from CSO 217 does not reach Mill Creek under existing conditions but will under proposed conditions, CSO remaining at CSO 217 is considered CSO volume ADDED to Mill Creek. The modeling performed for Lower Mill Creek Partial Remedy Study, dated December 2012, estimates that the proposed infrastructure at CSO 217 will achieve 13 MG of CSO volume remaining at CSO 217. Stream restoration for Kings Run is a component of the Revised Original Lower Mill Creek Partial Remedy (LMCPR). Kings Run has been reduced by urbanization from its historical extent to approximately 3,400 lineal feet of surface stream underlain by a combined sewer. Stream erosion throughout Kings Run risks exposing the existing underlying combined sewer. Approved Sustainable Infrastructure Project from Planning and Design The current Kings Run sustainable infrastructure project approved by the former Program Advisory Committee (PAC), currently known as the Capital Expenditure Committee (CapEx) from the project planning phase, and subsequently modified during design is summarized as follows: CSO 217/483 Source Control Phase A: o Stream Separation: Ponds 1-4 Stormwater Detention; o Sewer Separation: Kings Run Drive/Winton Ridge Lane Sewer Separation CSO 217/483 Source Control Phase B: Wooden Shoe CSO Storage Tank; Kings Run Stream CSO 217/483 Source Control Phase C: Winton Road Sewer Separation The Phase A stormwater detention basins and components of the Phase C sewer separation are anticipated to mitigate CSO events at CSO 217. Because the proposed detention basins and sewer separation upstream of CSO 217 do not by themselves achieve the WWIP goal for CSO 217, the original Kings Run planning study identified a 20 MGD enhanced high rate treatment (EHRT) plant to further reduce CSO volume. A 1.5 MG CSO storage tank was identified in the Revised Original LMCPR to replace the EHRT as the recommended solution to achieve the LMCPR Alternative goal for CSO 217 under Phase B. Section 3.2 Project Objectives Project Objectives Established Prior to the Planning Effort CSO Mitigation: The project objective related to CSO mitigation is to identify the most cost effective means of implementing a storage tank at CSO 217 to provide CSO volume control to support LMCPR goals. The Revised Original LMCPR includes a new 1.5 MG storage tank for control of remaining overflow to maximize CSO reduction at existing CSO 217. DRAFT 10/03/2014

8 CSO 217/483 Source Control Phase B 8 Water Quality: The proposed CSO storage tank will capture and convey to treatment combined sewage that is currently discharged into Kings Run at CSO 217, mitigating this source of pollution. Kings Run stream improvements are intended to create a stable stream channel and reduce stream bed and bank erosion, improving water quality and enhancing aquatic and riparian habitat. Address Community Concerns: Both the proposed CSO storage tank and Kings Run stream improvements are intended to address residents concerns regarding stream erosion and CSO odor problems Project Objectives Established During the Planning Effort Asset Management: During planning, an additional project objective was identified to stabilize Kings Run to protect the existing combined sewer underlying the stream Unique Project Constraints, Influences, or Issues affecting the Project Residents of Wooden Shoe Hollow are engaged and vocal activists for remedies to stream erosion and CSO odor problems. Community involvement and proximity to residents may influence construction and operation considerations. The proposed CSO storage tank site is secluded with limited line-of-sight, but still may need visual screening. An existing 6-inch BP petroleum pipeline is located to the north of the proposed CSO storage tank site. Section 3.3 Boundary of the Analysis The boundary of analysis includes the current CSO 217 location and the Kings Run stream within the CSO 483 drainage area, in Wooden Shoe Hollow, between Winton Road and Winton Ridge Lane, in the Winton Hills neighborhood of Cincinnati (see Figure 2). Section 3.4 Project Coordination MSD Project Dependencies and Coordination Requirements CSO 217/483 Source Control Phase A Stream Separation, Ponds 1 4: This WWIP project is in design, is located in a portion of the Kings Run subwatershed upstream of CSO 217, and is scheduled for construction completion in November This project impacts the CSO 217/483 Source Control Phase B project, is a necessary predecessor, and coordination between projects is ongoing CSO 217/483 Source Control Phase A Sewer Separation, Kings Run Drive/Winton Ridge Lane: This WWIP project is in design, is located in a portion of the Kings Run subwatershed downstream of CSO 217, and is scheduled for construction completion in November This project impacts the CSO 217/483 Source Control Phase B project in that it conveys underflow from CSO 217 and the proposed CSO storage tank to the relocated CSO 483. The Kings Run solution removes the nested relationship of the two CSOs. This project is not a necessary predecessor, its sewer separation limits influence the sizing of the proposed CSO storage tank, and coordination between projects is ongoing CSO 217/483 Source Control Phase C Winton Road Sewer Separation: This WWIP project is in design, a portion of which is located in the Kings Run subwatershed upstream of CSO 217, and is scheduled for construction completion in December This project impacts the CSO 217/483 Source Control Phase B project, is not a necessary predecessor, its sewer separation limits influence the sizing of the proposed CSO storage tank, and coordination between projects is ongoing Intergovernmental Coordination Requirements This project does not require intergovernmental coordination, other than that required for permits and DRAFT 10/03/2014

9 CSO 217/483 Source Control Phase B 9 approvals from Ohio EPA, US Army Corps of Engineers (USACE), and the City of Cincinnati. Figure 2. Boundary of Analysis DRAFT 10/03/2014

10 Section 4 Strategies CSO 217/483 Source Control Phase B 10 Section 4.1 Strategy Development and Initial Screening of Strategies Strategy 0: Do Nothing A "do nothing strategy" does not meet the objectives of the project and has been screened out Strategy 1: Construct CSO Storage Tank and Stream Stabilization Improvements A CSO storage tank is the recommended solution to achieve the LMCPR Alternative goal for CSO 217. The tank is proposed to be constructed near the existing CSO 217 outfall pipe, east of Kings Run, in a relatively open, gently sloping area in the northern end of Wooden Shoe Hollow. This strategy would improve access to the CSO regulator and storage tank for maintenance, and address health and safety concerns. This approach also maximizes the utility of existing infrastructure and minimizes the introduction of new infrastructure that requires operation and maintenance. Stream stabilization is recommended to correct environmental degradation caused by channel instabilities in Kings Run and to prevent further degradation from occurring. Stream stabilization would be constructed in conjunction with the CSO storage tank to address community concerns, protect the existing underlying combined sewer, and to promote water quality. Construction of a CSO storage tank and stream stabilization improvements will be considered and carried forward. Section 4.2 Analysis of Strategies As noted above, Strategy 0 has been screened out. Strategy 1 was advanced for more detailed analysis. Additional analysis is more directly related to the development and analysis of alternatives; therefore, it will be addressed in Section 5. DRAFT 10/03/2014

11 Section 5 Alternatives CSO 217/483 Source Control Phase B 11 Section 5.1 Alternative Development Methodology Under Strategy 1, the alternatives development involves two primary components: Proposed configuration of the CSO storage tank Proposed method of stream stabilization for Kings Run downstream of the storage tank Since the development of the LMCPR Version 4.2 model, the project team has further calibrated the Kings Run sub-basin within MSDGC s System Wide Model (SWM) to meet MSD s Modeling Guidelines and Standards Volume I, System Wide Model, Revision 3 (dated February 2013). The results of the current model calibration and validation have been documented in the revised draft Design Level Modeling Report for Kings Run Revised Original LMCPR Project, dated August 7, This draft report has been submitted to the MSDGC Modeling Group for review and approval. Using the design level calibration of the Kings Run Model, the project team adjusted the size of the CSO storage tank to achieve 90% control of annual CSO volume in the Typical Year at CSO 217. The tank volume in this scenario was determined to be 1.5 MG, which includes a storage volume factor of safety of 25%. Approximately 76 MG of CSO reduction is attributable to the tank by itself, obtained by subtracting the existing CSO volume from the CSO volume achieved by the tank with no upstream improvements. For purposes of stream improvement analyses Kings Run stream discharges were developed using design storms based on NRCS (SCS) 24-hour rainfall distributions applied to subcatchments represented in the current Design Level SWMM modeling. The estimated peak flow rates were comparable to those developed using the earlier LMCPR Version 4.2 model. Alternatives related to the configuration of the proposed CSO storage tank are bound by the following criteria: It must be placed directly adjacent to the existing CSO 217 to maximize the utility of existing infrastructure and minimize the introduction of new infrastructure. It must be placed in a limited flat area adjacent to steep terrain. Utilizing existing Wooden Shoe Hollow Drive for access to the CSO tank site is considered undesirable due to potential residents concerns and neighborhood impacts and operational problems associated with shared access drives. All of these criteria result in limited alternatives for the location and configuration of the proposed CSO storage tank. Alternatives related to the proposed Kings Run stream stabilization must meet the following criteria: Limit the extent of stream improvements to that required to stabilize the channel and to not exacerbate flood elevations. Minimize the right-of-way required to construct stream improvements. Avoid MSDGC s responsibility for long-term maintenance of completed stream improvements. Finally, the alternatives were developed with constructability and compliance with regulatory requirements in mind. Identification and analysis of alternatives related to both the CSO storage tank and the Kings Run stream improvements were moderately difficult given the urban site constraints and the extent of integration required with SWMM modeling of system improvements proposed throughout the Kings Run DRAFT 10/03/2014

12 subwatershed. CSO 217/483 Source Control Phase B 12 Section 5.2 Alternative Analysis Methodology The alternatives identified per the methodology described under Section 5.1 were then evaluated using the same methodology. An opinion of project cost and an estimate of operation and maintenance costs were developed for each alternative. The opinion of probable cost can be found in Appendix A. Constructability and accessibility issues were considered within the cost estimation. Conceptual alternatives design plans can be found in Appendix B. Each CSO tank alternative was modeled using the current Kings Run SWMM Design Model to estimate the CSO mitigation achieved with each. Refer to Appendix C, CSO 217 Storage Tank Business Case Evaluation Technical Memorandum for additional details regarding the proposed CSO storage tank. Refer to Appendix D, Geomorphic Assessment and Conceptual Alternatives Memorandum (Kings Run) for additional details regarding the proposed Kings Run stream improvements. Infrastructure types and locations were discussed with MSDGC stakeholders and with residents of Wooden Shoe Hollow. The infrastructure being proposed under each alternative is similar to other infrastructure being designed and constructed elsewhere within MSDGC s system. Therefore, it is not anticipated that staffing and skill set issues are a factor in the analysis of the alternatives. Because each alternative will have very similar social and environmental impacts, the cost per gallon of each alternative plays the most significant role in the analysis. Clean Water Act Sections 401 and 404 permitting The project team met with USACE to identify the Clean Water Act (CWA) Section 404 permitting framework for the project. Pending jurisdictional determination, the permitting framework anticipates that impacts from placing fill associated with culvert piping installation in Kings Run stream would be mitigated by downstream stabilization improvements. Lengths of these stream impacts for each alternative are below the threshold impacts for authorization under applicable USACE Nationwide Permits (NWPs). Ohio EPA is to be consulted during 30% design to confirm this approach for CWA Section 401 Water Quality Certification (WQC) purposes. Under this scenario the work would be authorized by USACE for 404 permitting under a NWP. Depending upon Ohio EPA s position regarding the project: The work would be authorized for 401 WQC under a NWP; or An individual 401 WQC would be required, involving a more lengthy permitting process and potential long-term maintenance obligations under conditions of the WQC. Since MSDGC prefers to neither own nor maintain the stream, those maintenance obligations would potentially require identification of an entity to provide stewardship of the stream, and permanent conservation easements on the private properties traversed by Kings Run. This is the basis on which project scheduling and right-of-way were evaluated for purposes of this report. Right-of-Way The project team identified the properties potentially affected by the project in Wooden Shoe Hollow, from Dutch Colony Drive to Kings Run Drive, and from Winton Road to Winton Ridge Lane. Planning efforts minimized the amount of property to be acquired for the project. 4 property purchases involving 2 full takes, plus 2 partial takes, are anticipated at the CSO storage tank. Easements for stream improvements and for supplemental access alternatives were recognized to be DRAFT 10/03/2014

13 less costly than property purchases for those project components. CSO 217/483 Source Control Phase B 13 Stream improvements for purposes of this report were assumed to occur in permanent channel easements assuming a conservative permitting outcome as described in Section 5.2. In the event that permanent easements are not required, the layout would apply to temporary easements needed for constructing proposed stream improvements. The proposed CSO storage tank and Kings Run stream improvements are located on properties with a zoning use classification of SF-20, Single-family District. For purposes of this report the tank was assumed to be a public utility distribution system component, which may permitted only after review and approval of the conditional use by the Zoning Hearing Examiner, according to Cincinnati, Ohio, Code of Ordinances, Title XIV Zoning Code of The City of Cincinnati, Chapter 1403 Single-Family Districts. Parcel ID Numbers , , , , , and are located in a Hillside District zoning overlay, for which any excavation and/or fill must be approved through a hearing process conducted by the Zoning Hearing Examiner. See Figure 3 for a depiction of right-of-way associated with the project alternatives. DRAFT 10/03/2014

14 CSO 217/483 Source Control Phase B 14 Figure 3. Project Right-of-Way Section 5.3 Alternatives The following alternatives represent the project team s projection of the potential infrastructure sizing and locations based on the available data today. All final infrastructure sizing is pending approval of both the model calibration and the proposed infrastructure modeling. DRAFT 10/03/2014

15 Additionally, the following elements are common across alternatives: CSO 217/483 Source Control Phase B 15 Regulatory requirements/restrictions A review of regulatory requirements identified approvals, restrictions, and notifications affecting the construction and operation of facilities as follows: Permit-To-Install proposed sanitary sewer facilities will be required from Ohio EPA. Application for coverage under Ohio EPA s General Permit Authorization for Storm Water Discharges Associated with Construction Activity under the National Pollutant Discharge Elimination System will be required by filing a Notice of Intent (NOI) and receipt of approval letter granting coverage from the director of Ohio EPA. Permitting for compliance with CWA Sections 401 and 404 will be required. Impacts to regulated water resources by the proposed improvements are anticipated. The CSO storage tank facility will require a City of Cincinnati Buildings and Inspections Building Permit. A separate City of Cincinnati Zoning hearing process will be required because the CSO storage tank is a conditional zoning use, and for permitting of excavations and/or fills in a Hillside District. Portions of the project within City of Cincinnati Right-of-Way will require a Street Opening Permit through Cincinnati Department of Transportation and Engineering. The land in Wooden Shoe Hollow, where the proposed CSO storage tank and the Kings Run stream are located, is not situated in a flood zone as shown on FEMA Flood Insurance Rate Maps (FIRM) 39061C0209E, Effective Date 02/17/2010, and 39061C0217F, Effective Date 02/16/2012. These items, where they differ among alternatives, were captured under the construction cost and project cost associated with each alternative, but were not a significant factor in the analysis. Impact to WWIP schedule/impact on other work in the sewershed CSO mitigation achieved with this project at CSO 217 is key to adhering to the WWIP schedule and to controlling CSOs at CSO 483. This project receives flows from two upstream projects: CSO 217/483 Source Control Phase A Stream Separation, Ponds 1 4; and CSO 217/483 Source Control Phase C, Winton Road Sewer Separation. This project discharges flow to the downstream project CSO 217/483 Source Control Phase A Sewer Separation, Kings Run Drive/Winton Ridge Lane. The coordinated scheduling of these Kings Run solution projects is consistent with the WWIP schedule. Key stakeholders The key stakeholders identified for this project are MSDGC and the property owners/residents in Wooden Shoe Hollow. TBL analysis The environmental and social aspect of the triple bottom line analysis was performed on the basis that little distinction, if any, can be made among the environmental and social impacts of the various infrastructure alternatives. This data is summarized in the table in Section 5.4. The environmental and social scoring calculations can be found in Appendix A. Risk Project level risks were identified to be common across the various infrastructure alternatives and were characterized in risk registers for the project components. This data is summarized in the table in Section 5.4. The risk register can be found in Appendix A. CSO Storage Tank DRAFT 10/03/2014

16 CSO 217/483 Source Control Phase B 16 The tank location is proposed adjacent to the existing remotely located CSO 217 with some history of odor complaints; it is anticipated that a new CSO storage structure with a proper cleaning system and timely dewatering will not create new odor concerns. The added costs of a cover and other odor control provisions are not considered to be warranted for the CSO 217 storage tank, so were not a significant factor in the analysis. Structural design of the tank can accommodate loads associated with a cover such that a retrofit cover may be installed if odor concerns become a problem in the future. Budgetary construction costs for tank cover systems are estimated to range from approximately 500,000 to 2,000,000 for a 1.5 MG storage tank, and are not included in this AAR. The cost of providing a tank cover is dependent upon the intended purpose of the cover as well as the selected tank geometry. Refer to Appendix C, CSO 217 Storage Tank Business Case Evaluation Technical Memorandum for additional details regarding the proposed CSO storage tank. Kings Run stream stabilization Stream stabilization measures common to the various infrastructure alternatives include the following for the mitigation of existing erosional damage, promotion of habitat, improvement of water quality, and enhancement of aesthetics at Kings Run: Grade control structures, a combination of Newbury Riffles, log riffles, and step-pools throughout the upstream and downstream sub-reaches. Re-grading, toe stabilization and targeted surface treatment of steep banks in the upper section of the reach. Benchfull wetlands near the upstream end of the reach. Bank re-grading and riparian vegetation restoration in the downstream section of the reach. Channel rehabilitation work is to be limited in the middle sub-reach to the installation of two Newbury rock riffles in an effort to minimize disturbance to the existing privately owned structures that are encroached on the channel and to maintain depth of cover over the existing underlying combined sewer as much as possible. An alternate involving a complete lack of construction within the middle sub-reach was considered in order to avoid any direct disturbance to the structures. This alternate would require rock burial beneath the riffle immediately upstream of this sub-reach in order to prevent further upstream migration of any headcut that might form within the untouched stretch of stream. This headcut would reduce the cover on the underlying sewer to less than 2 feet in places. According to TV reports and field survey the 30-inch combined sewer is reinforced concrete pipe; according to the original sewer construction drawings the sewer pipe is not encased in concrete. This condition would potentially violate MSD minimum standards for sewer pipe in creek beds and shallow installations, so this alternate was not incorporated. Bank re-grading is included in the downstream section of the reach to prevent an increase in flood elevation due to proposed grade control structures. An alternate involving buried grade control structures was considered at this location to provide stability without increasing flood elevations. This alternate does not improve the riparian zone and so was not incorporated. Where total lengths of stream improvements differ among the various alternatives, quantities of specific stream stabilization practices vary slightly, but were not a significant factor in the analysis. Costs associated with minor changes in the quantity of one stabilization practice are assumed to be offset by corresponding changes in the quantities of other stabilization practices. The Geomorphic Assessment and Conceptual Alternatives Memorandum (Kings Run) which documents the fluvial geomorphic field assessment performed by the project team and provides a range of conceptual alternatives for channel improvement can be found in Appendix D. DRAFT 10/03/2014

17 CSO 217/483 Source Control Phase B 17 General Infrastructure types and locations were discussed with MSDGC stakeholders and with residents of Wooden Shoe Hollow. The infrastructure being proposed under each alternative is similar to other infrastructure being designed and constructed elsewhere within MSDGC s system. Therefore, it is not anticipated that staffing and skill set issues are a factor in the analysis of the alternatives. Because each alternative will have very similar social and environmental impacts, the cost per gallon of each alternative plays the most significant role in the analysis Alternative 1.1 The alternative includes a circular CSO storage tank with a nominal storage volume of 1.5 MG, gravityin/gravity-out flow control, cast-in-place concrete in-ground construction, no cover (can be retrofit in the future if needed), no odor control (can be retrofit in the future if needed), automatic flushing tank cleaning system, screening by the use of an overflow bar screen, floatables control by the use of an overflow baffle, a support building, and utilities including potable water, electric, and SCADA communications. Refer to Appendix C, CSO 217 Storage Tank Business Case Evaluation Technical Memorandum for additional details. Access to the CSO storage tank site includes replacing the existing steep and narrow access drive with a new wider and more gently sloping drive proceeding easterly from Winton Road, aligned adjacent to the existing CSO 217 regulator structure, crossing Kings Run, and continuing to and around the tank. Proposed culvert piping will convey Kings Run stream flows below the access drive, resulting in approximately 250 linear feet of stream impact. A stormwater detention basin is included to mitigate the increase in site imperviousness affecting runoff to Kings Run. The alternative includes rerouting the existing combined sewer underflow piping to accommodate the proposed CSO storage tank. The alternative includes stream stabilization measures comprising bank re-grading, grade control structures and limited benchfull wetlands along a total stream length of approximately 3,075 feet. The alternative includes 4 property purchases at the CSO storage tank site (2 full takes, plus 2 partial takes), and 17 properties along Kings Run on which easements (assumed permanent) are needed for stream improvements. An opinion of probable construction cost (in 2018 dollars) of the alternative is 13,167,500, with a total project cost of 18,999, Alternative 1.2 The alternative is the same as Alternative 1.1 except that access to the CSO storage tank site includes maintaining the existing steep and narrow access drive from Winton Road, and constructing a new, supplemental access drive proceeding westerly from Winton Ridge Lane, to and around the tank, and continuing to the existing CSO 217 regulator structure, crossing Kings Run. The supplemental access drive would require additional easements so that the alternative includes one temporary easement and one permanent easement along the supplemental access route, 4 property purchases at the CSO storage tank site (2 full takes, plus 2 partial takes), and 17 properties along Kings Run for which easements (assumed permanent) are needed for stream improvements. An opinion of probable construction cost (in 2018 dollars) of the alternative is 13,219,600, with a total project cost of 19,409,900. DRAFT 10/03/2014

18 CSO 217/483 Source Control Phase B Alternative 2.1 The alternative includes a rectangular CSO storage tank with a nominal storage volume of 1.5 MG, gravity-in/gravity-out flow control, cast-in-place concrete in-ground construction, no cover (can be retrofit in the future if needed), no odor control (can be retrofit in the future if needed), automatic flushing tank cleaning system, screening by the use of an overflow bar screen, floatables control by the use of an overflow baffle, a support building, and utilities including potable water, electric, and SCADA communications. Refer to Appendix C, CSO 217 Storage Tank Business Case Evaluation Technical Memorandum for additional details. Access to the CSO storage tank site includes replacing the existing steep and narrow access drive with a new wider and more gently sloping drive proceeding easterly from Winton Road, aligned adjacent to the existing CSO 217 regulator structure, crossing Kings Run, and continuing to and around the tank. Proposed culvert piping will convey Kings Run stream flows below the access drive, resulting in approximately 400 linear feet of stream impact. A stormwater detention basin is included to mitigate the increase in site imperviousness affecting runoff to Kings Run. The alternative includes rerouting the existing combined sewer underflow piping to accommodate the proposed CSO storage tank. The alternative includes stream stabilization measures comprising bank re-grading, grade control structures and limited benchfull wetlands along a total stream length of approximately 2,925 feet. The alternative includes 4 property purchases at the CSO storage tank site (2 full takes, plus 2 partial takes), and 17 properties along Kings Run on which easements (assumed permanent) are needed for stream improvements. An opinion of probable construction cost (in 2018 dollars) of the alternative is 14,851,000, with a total project cost of 21,090, Alternative 2.2 The alternative is the same as Alternative 2.1 except that access to the CSO storage tank site includes maintaining the existing steep and narrow access drive from Winton Road, and constructing a new, supplemental access drive proceeding westerly from Winton Ridge Lane, to and around the tank, and crossing Kings Run, continuing to the existing CSO 217 regulator structure. The supplemental access drive would require additional easements so that the alternative includes one temporary easement and one permanent easement along the supplemental access route, 4 property purchases at the CSO storage tank site (2 full takes, plus 2 partial takes), and 17 properties along Kings Run for which easements (assumed permanent) are needed for stream improvements. An opinion of probable construction cost (in 2018 dollars) of the alternative is 14,872,600, with a total project cost of 21,462,800. DRAFT 10/03/2014

19 Section 5.4 Summary Comparison of Alternatives CSO 217/483 Source Control Phase B 19 P Alternate Value Triple Bottom Line Risk Comments Alternative 1.1 Alternative 1.2 Alternative 2.1 Alternative 2.2 NPV (Project Cost in 2006 Dollars) Construction Cost (2018 Dollars) O&M (unit/yr) Env. Score Social Score 0.19/gallon 14,275,700 13,167,500 41, Risk Severity Score range from 4 to /gallon 14,583,800 13,219,600 41, Risk Severity Score range from 4 to /gallon 15,846,700 14,851,000 41, Risk Severity Score range from 4 to /gallon 16,126,200 14,872,600 41, Risk Severity Score range from 4 to 36 DRAFT 10/03/2014 P

20 Section 5.5 Recommendation CSO 217/483 Source Control Phase B 20 The project team recommends implementing Alternative 1.1, based on its comparatively lower construction and project cost. Alternative 1.1 recommended infrastructure components are summarized as follows: 1.5 MG CSO 217 Storage Tank Criteria Recommendation Comments Flow Control Gravity-in/Gravity-out Lowest lifecycle cost Tank Geometry Circular, 140 feet Diameter, 16.5 feet Storage Depth Lowest cost, dependent on final site analysis Construction Material Cast-in-place Concrete In-ground construction, long life Cover None Remote location with little potential for odor complaints, can be retrofit in future if needed Odor Control None Remote location with little potential for odor complaints, can be retrofit in future if needed Tank Cleaning Automatic Flushing System Lowest lifecycle cost Screening Overflow Bar Screen Prevent large debris from entering the creek Floatables Control Overflow baffle A baffled overflow weir will help contain floatables within the storage tank for return to combined sewer during tank draining Utilities Potable Water, Electric Natural Gas (optional) SCADA Communications No backup power Site improvements Improved access drive from Winton Road to the CSO storage tank site. Culvert piping to convey Kings Run stream flows below the access drive. A stormwater detention basin to mitigate the increase in site imperviousness affecting runoff to Kings Run. Rerouting the existing combined sewer underflow piping to accommodate the proposed CSO storage tank. Kings Run stream stabilization Install grade control structures, a combination of Newbury Riffles, log riffles, and step-pools throughout the upstream and downstream sub-reaches. Re-grade the steep left banks in the upper section of the reach. Stabilize the toe of the right bank in the upper section of the reach. Install benchfull wetlands near the upstream end of the reach. Install targeted surface treatment of steep, unprotected sections of the right bank in the upper section of the reach. DRAFT 10/03/2014

21 CSO 217/483 Source Control Phase B 21 Restore riparian vegetation along the left bank of the downstream section of the reach, and in areas disturbed by this project. The stream s middle sub-reach will receive limited stabilization to minimize disturbance to existing privately owned structures that are encroached on the channel. Kings Run stream stabilization estimated construction cost of 850,000 is included in this AAR Each alternative satisfies the objectives of the project by implementing a storage tank at CSO 217 to provide CSO volume control, improving water quality by mitigating the CSO pollution source and by effecting Kings Run stream stabilization practices, addressing community concerns regarding stream erosion and CSO odors, and protecting the existing sewer asset underlying the stream. Each alternative meets WWIP requirements, is consistent with MSD standards, requires a PTI, and requires new easements and property acquisition. Each alternative has essentially the same risk and socioeconomic and environmental benefit. In comparing Alternative 1.1 with Alternative 1.2, and Alternative 2.1 with Alternative 2.2, the easterly access drive associated with Alternatives 1.2 and 2.2 increases the estimated construction and right-ofway costs without a clear commensurate benefit. Therefore, Alternatives 1.2 and 2.2 are eliminated from consideration. Comparison of the remaining alternatives, Alternatives 1.1 and 2.1 primarily boils down to the installation of a circular versus rectangular CSO storage tank. The construction cost and project cost associated with the circular tank in Alternative 1.1 are each lower than the corresponding costs associated with the rectangular tank in Alternative 2.1. A value engineering study is required for the project since its construction costs is over 5 million. The sewer connection credits program is not applicable to projects involving CSOs. DRAFT 10/03/2014

22 CSO 217/483 Source Control Phase B 22 Section 6 Execution Plan Section 6.1 Budget Cost Estimate A planning level (class IV) estimate was completed for the recommended alternative by the project team: Estimate Item Planning/Study 389, ,200 Design 908, ,200 Preconstruction Services 395, ,000 Miscellaneous Expense 224, ,800 Right of Way 1,544,100 1,672,100 Construction 11,548,700 13,167,500 Contingency 1,316,700 1,316,700 Construction Services 285, ,600 Interest/Financing 493, ,800 Total Project Cost 17,106,400 18,999,900 Right of way costs have been developed by the project team Legislative History Prior legislation associated with the project is as follows: Planning legislated in the 2013 CIP Book Design legislated in the 2013 CIP Book Preconstruction Services legislated in the 2013 CIP Book Right of Way legislated in the 2013 CIP Book Miscellaneous Expense legislated in the 2013 CIP Book Additional funding beyond amounts previously legislated may be necessary to cover design and other costs Proposed Legislation & Funding Sources The project is proposed to be legislated as a Capital Improvement Project under Wet Weather Improvement Project (WWIP). Construction Legislation is proposed as follows: Construction legislation proposed for 2015 Construction Services proposed for 2015 Interest/Financing proposed for 2015 The project has been identified as a potential Ohio Water Development Authority (OWDA) loan project. DRAFT 10/03/2014

23 CSO 217/483 Source Control Phase B 23 Section 6.2 Schedule The schedule for the project is proposed as follows per the project Master Schedule: Activity Expected Start Expected Finish Duration Design 09/02/ /13/ months ROW 12/31/ /28/ months Permitting 04/21/ /21/ months Legislate-Bid-Award 07/18/ /16/ months Construction 01/17/ /17/ months Closeout 09/18/ /18/ months Potential consequences associated with delaying this project may include enforcement actions as a result of delayed compliance with consent decree requirements. Section 6.3 Scope Summary of Project Scope Construct in-ground CSO storage tank downstream of existing CSO 217: Include flow regulation, screening, flushing, dewatering, and controls and monitoring systems Relocate existing 27-inch combined sewer underflow piping downstream of existing MH Install storm drainage culvert piping Construct access drive, utilities and site improvements associated with the tank Construct Kings Run stream stabilization improvements Install grade control structures Construct bank re-grading Construct toe stabilization and targeted surface treatment Construct benchfull wetlands and riparian restoration Functional Requirements and Design Basis Design Criteria CSO storage tank: CSO storage tank volume of 1.5 MG, resulting in annual CSO Volume Remaining of 19 MG in the Typical Year, based on 90% control criteria using current Design Level SWMM modeling. Tank overflow weir sized to pass the 100-year, 24-hr storm event with nominal increase in upstream hydraulic grade line compared to current conditions. Kings Run stream stabilization: Grade control structures sized for stability at the proposed 100- year, 24-hr storm event. Habitat features, armoring, and channel form informed by ODNR and Ohio EPA guidance, and by regional curves and reference streams. Storm sewer systems sized in accordance with Stormwater Management Utility regulations using the NRCS (SCS) runoff curve number method for the 10-year and 25-year storm events. Sanitary sewer systems sized in accordance with MSDGC Rules and Regulations. Alignment and Depth of Sewer Alignments and depths of the CSO storage tank and sanitary and combined sewers are arranged to provide gravity-in and gravity-out tank operation, and to maintain continuity of piping and allow for connections to existing piping. The depth of the tank dewatering piping is influenced by the depth DRAFT 10/03/2014

24 CSO 217/483 Source Control Phase B 24 of the relocated existing 27-inch combined sewer underflow piping downstream of existing MH Alignment and depth of storm drainage culvert piping is consistent with the existing Kings Run alignment and profile through the affected stream reach. Existing Kings Run stream alignment is to be maintained, stabilized with grade control structures, armoring, and channel form modifications. Easement Requirements/Property Acquisition Four property purchases are needed to construct and operate the proposed CSO storage tank, involving two full residential takes, one partial residential take, and one partial take from the Cincinnati Board of Education. Channel easements are needed to construct and operate the proposed Kings Run stream stabilization improvements involving 17 private, residential parcels. These easements are assumed for purposes of this report to be permanent, depending upon permitting conditions. In the event that permanent easements are not required, the easements would be temporary for constructing proposed stream improvements. There is a field adjacent to the project area at 5115 Wooden Shoe Lane which could be used for a temporary construction staging/lay down area, specific requirements for which are to be determined by the Contractor. Permits Anticipated Permit-To-Install proposed sanitary sewer facilities will be required from Ohio EPA. Ohio EPA National Pollution Discharge Elimination System construction stormwater authorization will be required. Permitting for compliance with CWA Sections 401 and 404 will be required. o Based on agency consultations the project is eligible for CWA Section 404 authorization by USACE under a NWP. o The project would be authorized by Ohio EPA for CWA Section 401 WQC under a NWP, or under an individual WQC, to be determined during 30% Design. The CSO storage tank facility will require a City of Cincinnati Buildings and Inspections Building Permit, and a hearing and decision by the City of Cincinnati Zoning Hearing Examiner for approval of development in a Hillside District. City of Cincinnati Zoning conditional zoning use approval is required for the CSO storage tank. Portions of the project within City of Cincinnati Right-of-Way will require a Street Opening Permit through Cincinnati Department of Transportation and Engineering. Temporary By-Pass Plan Temporary bypass procedures will maintain sewage flow within the existing sewers at all times during construction by by-pass pumping or diverting sewage flow into temporarily installed conduit in accordance with MSDGC requirements. Dry weather flows shall be maintained in the existing combined sewer and sanitary sewers at all times until the dry weather flows are diverted from the existing sewers into the proposed sewers Work Performed in Planning/Anticipated Work in Design Utility Information Existing utility information was reviewed in the vicinity of the project, obtained variously through DRAFT 10/03/2014

25 CSO 217/483 Source Control Phase B 25 OUPS requests, surveyed utility structures and utility marking locations, and direct project team coordination with utility agencies. Aerial electric, telephone and cable television utilities are on a pole line along the west side of Winton Road, across from the project site. Two separate 6-inch gas mains are located on the west side of Winton Road: one approximately 1,500 feet south of the project site, and one approximately 1,700 feet north of the project site (a 20-inch gas feeder line on the west side of Winton Road, across from the project site is not available for service connections). A 12-inch water main is located along the northbound curb lane of Winton Road at the project site. An existing 6-inch BP petroleum pipeline is located to the north of the proposed CSO storage tank site. 12-inch sanitary sewer and 27-inch combined sewer underflow piping traverse the CSO storage tank site. The 27-inch combined sewer underflow piping becomes 30 inches in size as it runs below the stream channel of Kings Run. Storm drainage piping is not evident within the limits of work associated with the CSO storage tank and Kings Run stream improvements. Private utility service connections have not been located at this time. Additional coordination with utility companies will be required during Design for coordination of connections to existing utilities, or protection or relocation of existing utilities. Survey and Fieldwork A detailed field topographic survey of the Kings Run stream corridor was performed by the project team during Planning. Documentation of the Kings Run stream channel topographic survey can be found in the Kings Run Stream Survey and Flow Monitoring and Modeling Memorandum in Appendix E. A full topographic survey should be conducted during Design, including the area within the work limits associated with the CSO storage tank and access route, and Kings Run stream overbank/floodplain areas in Wooden Shoe Hollow. No boundary surveying was performed during Planning. A field boundary survey and courthouse research should be conducted during Design, and plats prepared delineating the required permanent and temporary easements and lot splits/consolidations for the project. Geotechnical No geotechnical work was performed during Planning. Geotechnical investigations should be performed during Design to identify soil conditions within work limits associated with the CSO storage tank, along pipe alignments, and at adjacent hillsides for slope stability purposes. Monitoring and Modeling SWMM modeling has been performed in Planning and documented in the draft Design Level Modeling Report for Kings Run Revised Original LMCPR Project, dated March 7, This draft report has been submitted to the MSDGC Modeling Group for review and approval. Using the design level calibration of the Kings Run Model, the project team optimized the size of the CSO storage tank to achieve the same CSO mitigation as estimated by the modeling performed for the 2012 LMCPR Study. Kings Run stream discharges were developed in Planning for analyses of stream improvements using design storms based on NRCS (SCS) 24-hour rainfall distributions applied to subcatchments represented in the current Design Level SWMM modeling. These flow rates were used in HEC-RAS modeling of the Kings Run stream corridor. Documentation of the modeling of Kings Run stream flow can be found in the Kings Run Stream Survey and Flow Monitoring and Modeling Memorandum DRAFT 10/03/2014

26 in Appendix E. CSO 217/483 Source Control Phase B 26 It is anticipated that SWMM modeling work will be required during Design, inputting proposed control measures and infrastructure to estimate impacts to associated storm, sanitary, and combined sewer systems, forecast inflow and CSO reductions, and verify capacity of proposed infrastructure. HEC-RAS modeling of Kings Run should be performed during Design to substantiate the capacity and stability of the final stream design. Collection system flow monitor data was collected at 18 locations throughout the watershed at various times from November 2008 to June Additional collection system flow monitoring is anticipated during Design to evaluate post-construction performance of proposed upstream improvements under CSO 217/483 Source Control Phase A Stream Separation, Ponds 1 4, and CSO 217/483 Source Control Phase C, Winton Road Sewer Separation. Environmental Site Assessment Phase I Environmental Site Assessments (ESAs) were previously completed by the project team for a few of the potentially affected parcels under Projects and Phase I ESAs in accordance with ASTM Standard E should be performed during Design on the remainder of parcels that may be impacted within the limits of work associated with the CSO storage tank and Kings Run stream improvements. Misc. Reports, Studies, Analysis, Etc. Waters of the U.S. assessment was previously conducted by the project team for a limited reach of Kings Run under Project Waters of the U.S. assessments should be performed during Design to identify and delineate streams and/or wetlands and perform threatened and endangered species review in the remainder of areas that may be impacted within the limits of work associated with the CSO storage tank and Kings Run stream improvements. Fluvial geomorphic field assessment of the entire approximately 3,400 feet length of King s Run stream was conducted during Planning to evaluate spatial trends of current stream stability and how geomorphic conditions may influence stream bank protection design strategies. The Geomorphic Assessment and Conceptual Alternatives Memorandum (Kings Run) which documents the fluvial geomorphic field assessment performed by the project team and provides a range of conceptual alternatives for channel improvement can be found in Appendix D. It is not anticipated that additional geomorphic assessment work will be required during Design. Monitoring of basic water quality and stream stage in Kings Run was conducted by the project team during Planning to characterize existing stream conditions. Documentation of the monitoring of Kings Run stream flow can be found in the Kings Run Stream Survey and Flow Monitoring and Modeling Memorandum in Appendix E. It is not anticipated that additional stream monitoring work will be required during Design. Section 6.4 Roles and Responsibilities Engineering Management is responsible for managing the project through Design and Construction. MSDGC Watershed Operations Division is responsible for operation and maintenance of the CSO storage tank. Todd Trabert with Collections has been involved in the development and review of alternatives. MSDGC does not own Kings Run, so long-term, post-construction stream maintenance will involve identifying and engaging homeowners, water resource interest groups, and other community resources DRAFT 10/03/2014

27 CSO 217/483 Source Control Phase B 27 to carry out stewardship of the completed stream stabilization improvements. MSDGC Environmental Programs has been involved in the development and review of alternatives. Section 6.5 Project Risks Risks were evaluated for project components in accordance with MSD Risk Management Guidelines. Risk assessment evaluated Environmental, Health & Safety, Legal, Management, and Technical categories. Risk Severity Scores for these issues range from 4 to 36. Refer to the Risk Register in Appendix A Wet Weather Flows An undersized tank design poses a low risk of permit violation due to CSO 217 overflowing more than allowable CSO mitigation targets. The tank is being sized with MSDGC's SWMM model to provide contingency storage during the Typical Year storm, and to limit the overflow activations to achieve CSO mitigation targets. Undersized tank or pipe designs pose a low risk of increasing the upstream hydraulic grade line being compared to current levels during wet weather. The tank overflow weir is sized to pass the 100-year, 24-hour storm event with nominal increase in upstream hydraulic grade line compared to current conditions. The project involves a very low risk of increasing stream erosion and flooding in Kings Run during wet weather. Proposed stream flows for design storms will be attenuated in comparison to current conditions. Grade control structures along the channel bed, sized for stability at the 100-year, 24-hour storm event, are intended to minimize the risk of further stream incision and potential impacts to the underlying existing sewer Property/Easements Delay in obtaining the required properties and easements pose a medium risk. Inability to reach a property settlement with property owners may result in forced appropriations, increases in legal and/or appropriations costs, and a negative public image. Responses include early negotiations with property owners, and adding project schedule and budget contingencies to account for appropriations delays Geotechnical Unexpected soil conditions encountered during construction, groundwater influences and construction near steep hillsides each pose medium risks. Results of geotechnical investigation performed during the design phase will inform design and construction procedures for the proposed improvements Noise, Odor, and Traffic Noise and traffic are not identified to be sources of risk on this project. Odor complaints pose a low risk. The CSO storage tank is not planned to have a cover; odors may be caused by failure of the tank flushing system and/or untimely draining of the tank following storm events. Due to the relatively remote tank location, the risk of odor complaints is limited to a few nearby properties. Remote monitoring of tank levels, draining and flushing systems and routine tank inspection following storm events will be implemented. No further response action recommended at this time. DRAFT 10/03/2014

28 Section 7 - Major References CSO 217/483 Source Control Phase B 28 Cost Estimate Location: Status: Completed Appendix A, this AAR Plan Location: Status: Completed Appendix B, this AAR Modeling Report Location: Status: Other (specify): Draft Design Level Modeling Report for Kings Run Revised Original LMCPR Project, dated August 7, 2014 submitted to the MSDGC Modeling Group for review and approval CSO 217/483 Source Control Phase B Planning-Level Modeling Memorandum, dated August 7, 2014 CSO 217 Storage Tank Alternative Analysis Technical Memorandum: Status: Completed Appendix C, this AAR Kings Run Fluvial Geomorphic Assessment Memorandum: Status: Completed Appendix D, this AAR Kings Run Stream Survey and Flow Monitoring and Modeling Memorandum: Status: Completed Appendix E, this AAR [Additional Reference] Location: Status: Choose an item. [Link Here from Sharepoint or Planning Folder] DRAFT 10/03/2014

29 Appendix A

30 PID : CSO 217/483 Source Control Phase B Planning - CSO Storage Tank & Stream Stabilization 10/3/2014 Summary - OPINION OF PROBABLE COST Alternative No. and Description Quantity, Unit Approximate CSO Construction Cost in Project Cost in Project Cost in Cost Per Gallon in Present Worth of Reduction 2018 Dollars 2018 Dollars 2006 Dollars 2006 Dollars Annual O&M (MG) Alt. 1.1 Circular Tank, West Access & Kings Run Stream Stabilization 1 LS - See Tabs 13,167,500 18,999,900 14,275, ,223,400 Alt. 1.2 Circular Tank, East Access & Kings Run Stream Stabilization 1 LS - See Tabs 13,219,600 19,409,900 14,583, ,223,400 Alt. 2.1 Rectangular Tank, West Access & Kings Run Stream Stabilization 1 LS - See Tabs 14,851,000 21,090,800 15,846, ,231,700 Alt. 2.2 Rectangular Tank, East Access & Kings Run Stream Stabilization 1 LS - See Tabs 14,872,600 21,462,800 16,126, ,231,700 POWER Engineers, Inc. Page 1 of 20

31 PLANNING OPINION OF PROBABLE CONSTRUCTION COST POWER Engineers, Inc. PN: PROJECT: PID : CSO 217/483 Source Control Phase B Planning - CSO Storage Tank & Stream Stabilization LOCATION: College Hill, Winton Hills Neighborhoods DATE: 10/3/2014 * Items not included in CSO 217 Storage Tank Business Case Technical SUBJECT: Alt. 1.1 Circular Tank, West Access & Kings Run Stream Stabilization Memorandum, Appendix C, or in Geomorphic Assessment and Conceptual QUARTER/YEAR: Q Alternatives Memorandum (Kings Run), Appendix D Item Code Description Quantity Unit Unit Costs Labor Material Equipt Sub Temp Matl. Equipt Rental Other Costs Total Unit Cost Total Item Cost Assumptions/Calcs Division 02 - Site Work and Demolition * Demo Two-Story House 3 EACH , , , Barn/shed Remove Asphalt Paving 4 CUYD Remove Sidewalks 750 SQFT , Remove Curb & Gutter 75 LNFT Remove Fence 700 LNFT , Saw Cut Asphalt 100 LNFT Remove & Reinstall Guardrail 100 LNFT , Demo - Miscellaneous 1 ACRE , , , Allowance Disconnect Existing Utilities 1 EACH SUBTOTAL 35, Division 02 - Site Preparation * Clearing & Grubbing - Trees 2.81 ACRE 2, , , , , Cut-Store-Spread Topsoil 2,344 CUYD , SUBTOTAL 36, Division 31 - Erosion Control * Stilling Basin, complete , , , Site preparation, excavation, fill, gravel bedding, 700 CY riprap, geotextile, restoration 2 EACH Rolled Erosion Control Mat SQFT , Rip Rap 6 CUYD SUBTOTAL 167, Division 31 - Earthwork * Fill w/ Site Earth 3,418 CUYD , Haul, off-site 15,539 CUYD , Fine Grade for Pavement SQFT , Fine Grade for Slopes SQFT , Excavate Soil - Bulk 7,400 CUYD , SUBTOTAL 292, Division 32 - Paving & Roadway * " Concrete Paving, Non-Reinforced 1187 SQYD , Concrete Driveway Apron 1 EACH , , , Concrete driveway apron 8" thk, no base, commercial (RS Means) Concrete Sidewalk (5") 750 SQFT , Concrete Curb & Gutter 75 LNFT , Pavement Misc. 1 EACH , , , Allowance: striping, wheel stops, access controls (RS Means) SUBTOTAL 56, Division 32 - Landscaping * Seeding w/ Fertilizer & Mulch 12,400 SQYD , Landscaping Allowance 1 EACH , , , Screening, east side SUBTOTAL 31, POWER Engineers, Inc. Page 2 of 20

32 PLANNING OPINION OF PROBABLE CONSTRUCTION COST POWER Engineers, Inc. PN: PROJECT: PID : CSO 217/483 Source Control Phase B Planning - CSO Storage Tank & Stream Stabilization LOCATION: College Hill, Winton Hills Neighborhoods DATE: 10/3/2014 * Items not included in CSO 217 Storage Tank Business Case Technical SUBJECT: Alt. 1.1 Circular Tank, West Access & Kings Run Stream Stabilization Memorandum, Appendix C, or in Geomorphic Assessment and Conceptual QUARTER/YEAR: Q Alternatives Memorandum (Kings Run), Appendix D Item Code Description Quantity Unit Unit Costs Labor Material Equipt Sub Temp Matl. Equipt Rental Other Costs Total Unit Cost Total Item Cost Assumptions/Calcs Division 33 - Storm Sewer * Catch Basin VLF , Standard Type "P" Manhole (60" D) 30 VLF , " Water Tight MH Cover/Frame 2 EA Concrete Headwall, 18" Opening 1 EACH , , , <= 18" Video Tape Installed Sewer 80 LNFT >=21" Video Tape Installed Sewers 200 LNFT Excavate Manhole 136 CUYD , Backfill Trench with CDF (Flowable Fill) 22 CUYD , Excavate Trench 768 CUYD , Washed Gravel Bedding 60 CUYD , Machine Backfill, Tamped 384 CUYD , Gravel Backfill, Tamped 223 CUYD , Reuse, On-Site 385 CUYD , " Storm Reinforced Concrete Pipe 80 LNFT , " Storm Reinforced Concrete Pipe 200 LNFT , ' Tall Storm Manhole Base 2 EACH , , " Top Transition Slab 2 EACH Vac Test Manhole 2 EACH " 400# Heavy Duty Manhole Cover/Frame 2 EACH Trench Box 2 EACH Concrete Headwall (mult. pipe opngs.) 2 EACH , , , SUBTOTAL 115, Division 33 - Water Utilities * Water Service Assembly 1 EACH , , From existing main at Winton Rd.: 450 LF 4-in. DIP, 4' deep, complete 28, w/tap, meter pit, excavation, backfill (RS Means) SUBTOTAL 28, Division 33 - Sanitary Sewer SUBTOTAL Division 33 - Gas, Electric and Communications Utilities * - Included in CSO 217 Storage Tank Business Case Technical Memorandum, Appendix C From existing pole line at Winton Rd.: 450 LF 2) 5-in. conduits, 3 ft. depth, complete w/concrete pad for utility-owned transformer, excavation, Electric Service 1 EACH , , , backfill (RS Means) From existing pole line at Winton Rd.: 450 LF 2) 4-in. conduit, complete Telco Service 1 EACH , , , w/excavation, backfill (RS Means) SUBTOTAL 49, Miscellaneous Divisions 02 to 46: Subtotal carried from CSO 217 Storage Tank Alternative Analysis Technical 1 EACH ,437, ,437, ,437, CSO Storage Tank, Complete Memorandum, Appendix C Division 35: Subtotal carried from Geomorphic Assessment and Conceptual Alternatives 1 EACH , , , Kings Run Stream Stabilization, Complete Memorandum (Kings Run), Appendix D SUBTOTAL 6,209, POWER Engineers, Inc. Page 3 of 20

33 PLANNING OPINION OF PROBABLE CONSTRUCTION COST POWER Engineers, Inc. PN: PROJECT: PID : CSO 217/483 Source Control Phase B Planning - CSO Storage Tank & Stream Stabilization LOCATION: College Hill, Winton Hills Neighborhoods DATE: 10/3/2014 * Items not included in CSO 217 Storage Tank Business Case Technical SUBJECT: Alt. 1.1 Circular Tank, West Access & Kings Run Stream Stabilization Memorandum, Appendix C, or in Geomorphic Assessment and Conceptual QUARTER/YEAR: Q Alternatives Memorandum (Kings Run), Appendix D Item Code Description Quantity Unit Unit Costs Labor Material Equipt Sub Temp Matl. Equipt Rental Other Costs Total Unit Cost Total Item Cost Assumptions/Calcs GENERAL CONDITIONS Percent of subtotal of above construction costs, includes bonding and 702, General Conditions 0.1 insurance SUBTOTAL 702, OPINION OF CONSTRUCTION COST - SUBTOTAL 7,724, Overhead , Profit , SUBTOTAL 8,883, Design Contingency 0.3 2,665, SUBTOTAL 11,548, Escalation to End of Construction Q ,618, TOTAL OPINION OF CONSTRUCTION COST Alternate ,167, PROJECT COST SUBTOTAL Total Opinion of Construction Cost 13,167,438 Value from above Right-of-Way 1,544,143 From ROW Calculations Right-of-Way Escalation to Start of Constructio Q ,897 Planning 389,200 Under Phase B Planning Task Order Planning Escalation to End of Planning 0 Under Phase B Planning Task Order Design 908, x^ (x = Construction Cost before escalation) for each: CSO tank + sitework, and stream stabilization Design Escalation to Start of Construction Q ,281 Pre-Construction Services , Treatment Plants, All Other Projects Street Opening Permits and Inspections 12 SQ YD 435 From CDOTE Fees Calculations Environmental Inspections 3400 LNFT 38, / linear foot of construction when w/i 100' of stream Geotechnical Report 12 Borings 49,500 Public Relations 50,000 Value based on project value (25k for 2MM) PTI , X Sanitary Sewer Construction Cost (Max 15,100) Railroad Permits 0 As Needed WPCLF Loan Origination Fees ( * All costs except Capitalized Interest) , As needed, for loans between 3,500,000 and 100,000, /404 Creeks and Outfalls 7,500 As needed permit fees Miscellaneous Costs Total 224,374 Miscellaneous Costs Escalation to End of Constr Q ,451 Capitalized Interest (0.05 * Years of Construction) ,779 Project Contingency 0.1 1,316,744 As defined from Manual Construction Services 78 Weeks 285,572 (2% pre-escalated const. cost + 700/week) x 1/number of project areas [spreadsheet tabs] Construction Services Escalation to End of Cons Q ,030 TOTAL OPINION OF PROJECT COST (Escalated to End of Project) 18,999,828 Alt. 1.1 Circular Tank, West Access & Kings Run Stream Stabilization De-Escalation Multiplier to 2006 Dollars PROJECT COSTS IN 2006 DOLLARS 14,275,635 POWER Engineers, Inc. Page 4 of 20

34 PID : CSO 217/483 Source Control Phase B Planning - CSO Storage Tank & Stream Stabilization 10/3/2014 Non-Annual Annual O&M Operation & Maintenance Description O&M Cost Notes Cost (Annualized) Alt. 1.1 Circular Tank, West Access & Kings Run Stream Stabilization Annual Operation & Maintenance Costs: Circular CSO Storage Tank 40,000 Pavement maintenance 493 Storm Drainage Piping 300 Kings Run routine stream maintenance 315 Annual Operation & Maintenance Costs are based on Planning Study Annual O&M from CSO 217 Storage Tank Business Case Technical Memorandum, Appendix C Cost () = 3250 SY * (0.13/SY, 2006) * ( Escalation Multiplier to Current) annual maintenance of pavement surface, shoulders, vegetation control, ditch cleaning, culvert/underdrain (adapted from ESTIMATING COST PER LANE MILE FOR ROUTINE HIGHWAY OPERATIONS AND MAINTENANCE, Project 07-12, January 2011, Department of Civil and Environmental Engineering, University of Wisconsin) 1.50/LF estimated annual pipe maintenance 550 LF stream, MSDGC premises only. Routine inspections, enforcement of easement restrictions, repairs at 200/year (NCDENR EEP Clemson/UNCW RR ); plus open space maintenance in riparian buffer areas at 115/year (DNREC PCStrategy BMP Cost Calculations 2010). Non-Annual Operation & Maintenance Costs: Kings Run Stream Stabilization: Monitoring - Years ,640 Maintenance - Years ,181 Costs are based on Planning Study Post-construction monitoring per 401/404 regulatory requirements: Baseline Year 1 at 13,200; plus Years 2-5 at 10,000 each; all annualized over 5 years (monitoring effort is highly dependent on permit requirements) Post-construction repair, fine-tuning during Years 1-2, at 15% of construction cost, annualized over 5 years for convenience (VA Stream Guide 2004) Annual Operation & Maintenance Present Worth Parameters: Start Year: As Noted End Year: As Noted Years for Present Worth Evaluation: 30 Uniform Series Present Worth Factor: Interest Rate, %: 5.00 Gradient Series Present Worth Factor: Annual Inflation (Escalation) Rate, %: 3.50 Description Start Year End Year CSO Storage Tank, Pavement maintenance, Storm Drainage piping, Kings Run stream routine maintenance , ,382 2, , ,871 1,063,805 Non-Annual Operation & Maintenance Present Worth Parameters: Start Year: As Noted End Year: As Noted Years for Present Worth Evaluation: 5 Uniform Series Present Worth Factor: Interest Rate, %: 5.00 Gradient Series Present Worth Factor: Annual Inflation (Escalation) Rate, %: 3.50 Description Start Year End Year Annual O&M Cost at Start Year Annual O&M Cost at Start Year Annual O&M Cost at End Year Annual O&M Cost at End Year Annual Incremental Increase Annual Incremental Increase Present Worth of Constant O&M Present Worth of Constant O&M Present Worth of Incremental O&M Present Worth of Incremental O&M TOTAL PRESENT WORTH OF O&M TOTAL PRESENT WORTH OF O&M Kings Run stream non-routine monitoring & maintenance ,821 40,169 1, ,427 13, ,499 TOTAL PRESENT WORTH OF ANNUAL AND NON-ANNUAL O&M COSTS 1,223,304 POWER Engineers, Inc. Page 5 of 20

35 PLANNING OPINION OF PROBABLE CONSTRUCTION COST POWER Engineers, Inc. PN: PROJECT: PID : CSO 217/483 Source Control Phase B Planning - CSO Storage Tank & Stream Stabilization LOCATION: College Hill, Winton Hills Neighborhoods DATE: 10/3/2014 * Items not included in CSO 217 Storage Tank Business Case Technical SUBJECT: Alt. 1.2 Circular Tank, East Access & Kings Run Stream Stabilization Memorandum, Appendix C, or in Geomorphic Assessment and Conceptual QUARTER/YEAR: Q Alternatives Memorandum (Kings Run), Appendix D Item Code Description Quantity Unit Unit Costs Labor Material Equipt Sub Temp Matl. Equipt Rental Other Costs Total Unit Cost Total Item Cost Assumptions/Calcs Division 02 - Site Work and Demolition * Demo Two-Story House 3 EACH , , , Barn/shed Remove Asphalt Paving 4 CUYD Remove Curb & Gutter 10 LNFT Remove Fence 700 LNFT , Saw Cut Asphalt 100 LNFT Remove & Reinstall Guardrail 100 LNFT , Demo - Miscellaneous 1 ACRE , , , Allowance Disconnect Existing Utilities 1 EACH SUBTOTAL 33, Division 02 - Site Preparation * Clearing & Grubbing - Trees 2.65 ACRE 2, , , , , Cut-Store-Spread Topsoil 2,239 CUYD , SUBTOTAL 34, Division 31 - Erosion Control * Stilling Basin, complete , , , Site preparation, excavation, fill, gravel bedding, 700 CY riprap, geotextile, restoration 2 EACH Rolled Erosion Control Mat SQFT , Rip Rap 18 CUYD , SUBTOTAL 163, Division 31 - Earthwork * Fill w/ Site Earth 3,118 CUYD , Haul, off-site 16,477 CUYD , Fine Grade for Pavement SQFT , Fine Grade for Slopes SQFT , Excavate Soil - Bulk 8,000 CUYD , SUBTOTAL 306, Division 32 - Paving & Roadway * " Concrete Paving, Non-Reinforced 1310 SQYD , Concrete Driveway Apron 1 EACH , , , Concrete driveway apron 8" thk, no base, commercial (RS Means) Concrete Curb & Gutter 10 LNFT Pavement Misc. 1 LNFT , , , Allowance: striping, wheel stops, access controls SUBTOTAL 56, Division 32 - Landscaping * Seeding w/ Fertilizer & Mulch 11,520 SQYD , Landscaping Allowance 1 EACH , , , Screening, east side SUBTOTAL 32, POWER Engineers, Inc. Page 6 of 20

36 PLANNING OPINION OF PROBABLE CONSTRUCTION COST POWER Engineers, Inc. PN: PROJECT: PID : CSO 217/483 Source Control Phase B Planning - CSO Storage Tank & Stream Stabilization LOCATION: College Hill, Winton Hills Neighborhoods DATE: 10/3/2014 * Items not included in CSO 217 Storage Tank Business Case Technical SUBJECT: Alt. 1.2 Circular Tank, East Access & Kings Run Stream Stabilization Memorandum, Appendix C, or in Geomorphic Assessment and Conceptual QUARTER/YEAR: Q Alternatives Memorandum (Kings Run), Appendix D Item Code Description Quantity Unit Unit Costs Labor Material Equipt Sub Temp Matl. Equipt Rental Other Costs Total Unit Cost Total Item Cost Assumptions/Calcs Division 33 - Storm Sewer * Catch Basin VLF , Standard Type "P" Manhole (60" D) 30 VLF , " Water Tight MH Cover/Frame 2 EA Concrete Headwall, 18" Opening 5 EACH , , , <= 18" Video Tape Installed Sewer 200 LNFT >=21" Video Tape Installed Sewers 200 LNFT Excavate Manhole 136 CUYD , Backfill Trench with CDF (Flowable Fill) 39 CUYD , Excavate Trench 993 CUYD , Washed Gravel Bedding 73 CUYD , Machine Backfill, Tamped 515 CUYD , Gravel Backfill, Tamped 271 CUYD , Reuse, On-Site 478 CUYD , " Storm Reinforced Concrete Pipe 200 LNFT , " Storm Reinforced Concrete Pipe 200 LNFT , ' Tall Storm Manhole Base 2 EACH , , " Top Transition Slab 2 EACH Vac Test Manhole 2 EACH " 400# Heavy Duty Manhole Cover/Frame 2 EACH Trench Box 4 EACH Concrete Headwall (mult. pipe opngs.) 2 EACH , , , SUBTOTAL 134, Division 33 - Water Utilities * Water Service Assembly 1 EACH , , From existing main at Winton Rd.: 450 LF 4-in. DIP, 4' deep, complete 28, w/tap, meter pit, excavation, backfill (RS Means) SUBTOTAL 28, Division 33 - Sanitary Sewer SUBTOTAL Division 33 - Gas, Electric and Communications Utilities * - Included in CSO 217 Storage Tank Business Case Technical Memorandum, Appendix C From existing pole line at Winton Rd.: 450 LF 2) 5-in. conduits, 3 ft. depth, complete w/concrete pad for utility-owned transformer, excavation, Electric Service 1 EACH , , , backfill (RS Means) From existing pole line at Winton Rd.: 450 LF 2) 4-in. conduit, complete Telco Service 1 LNFT , , , w/excavation, backfill (RS Means) SUBTOTAL 49, Miscellaneous Divisions 02 to 46: Subtotal carried from CSO 217 Storage Tank Alternative Analysis Technical 1 EACH ,437, ,437, ,437, CSO Storage Tank, Complete Memorandum, Appendix C Division 35: Subtotal carried from Geomorphic Assessment and Conceptual Alternatives 1 EACH , , , Kings Run Stream Stabilization, Complete Memorandum (Kings Run), Appendix D SUBTOTAL 6,209, POWER Engineers, Inc. Page 7 of 20

37 PLANNING OPINION OF PROBABLE CONSTRUCTION COST POWER Engineers, Inc. PN: PROJECT: PID : CSO 217/483 Source Control Phase B Planning - CSO Storage Tank & Stream Stabilization LOCATION: College Hill, Winton Hills Neighborhoods DATE: 10/3/2014 * Items not included in CSO 217 Storage Tank Business Case Technical SUBJECT: Alt. 1.2 Circular Tank, East Access & Kings Run Stream Stabilization Memorandum, Appendix C, or in Geomorphic Assessment and Conceptual QUARTER/YEAR: Q Alternatives Memorandum (Kings Run), Appendix D Item Code Description Quantity Unit Unit Costs Labor Material Equipt Sub Temp Matl. Equipt Rental Other Costs Total Unit Cost Total Item Cost Assumptions/Calcs GENERAL CONDITIONS Percent of subtotal of above construction costs, includes bonding and 705, General Conditions 0.1 insurance SUBTOTAL 705, OPINION OF CONSTRUCTION COST - SUBTOTAL 7,755, Overhead , Profit , SUBTOTAL 8,918, Design Contingency 0.3 2,675, SUBTOTAL 11,594, Escalation to End of Construction Q ,625, TOTAL OPINION OF CONSTRUCTION COST Alternate ,219, PROJECT COST SUBTOTAL Total Opinion of Construction Cost 13,219,568 Value from above Right-of-Way 1,861,738 From ROW Calculations Right-of-Way Escalation to Start of Constructio Q ,202 Planning 0 389,200 Under Phase B Planning Task Order Planning Escalation to End of Planning 0 Under Phase B Planning Task Order Design 0 911, x^ (x = Construction Cost before escalation) for each: CSO tank + sitework, and stream stabilization Design Escalation to Start of Construction Q ,483 Pre-Construction Services , Treatment Plants, All Other Projects Street Opening Permits and Inspections 12 SQ YD 435 From CDOTE Fees Calculations Environmental Inspections 3400 LNFT 38, / linear foot of construction when w/i 100' of stream Geotechnical Report 12 Borings 49,500 Public Relations 50,000 Value based on project value (25k for 2MM) PTI , X Sanitary Sewer Construction Cost (Max 15,100) Railroad Permits 0 As Needed WPCLF Loan Origination Fees ( * All costs except Capitalized Interest) , As needed, for loans between 3,500,000 and 100,000, /404 Creeks and Outfalls 7,500 As needed permit fees Miscellaneous Costs Total 225,796 Miscellaneous Costs Escalation to End of Constr Q ,651 Capitalized Interest (0.05 * Years of Construction) ,734 Project Contingency 0.1 1,321,957 As defined from Manual Construction Services 78 Weeks 286,487 (2% pre-escalated const. cost + 700/week) x 1/number of project areas [spreadsheet tabs] Construction Services Escalation to End of Cons Q ,158 TOTAL OPINION OF PROJECT COST (Escalated to End of Project) 19,409,891 Alt. 1.2 Circular Tank, East Access & Kings Run Stream Stabilization De-Escalation Multiplier to 2006 Dollars PROJECT COSTS IN 2006 DOLLARS 14,583,738 POWER Engineers, Inc. Page 8 of 20

38 PID : CSO 217/483 Source Control Phase B Planning - CSO Storage Tank & Stream Stabilization 10/3/2014 Non-Annual Annual O&M Operation & Maintenance Description O&M Cost Notes Cost (Annualized) Alt. 1.2 Circular Tank, East Access & Kings Run Stream Stabilization Annual Operation & Maintenance Costs: Circular CSO Storage Tank 40,000 Pavement maintenance 493 Storm Drainage Piping 300 Kings Run routine stream maintenance 315 Annual Operation & Maintenance Costs are based on Planning Study Annual O&M from CSO 217 Storage Tank Business Case Technical Memorandum, Appendix C Cost () = 3250 SY * (0.13/SY, 2006) * ( Escalation Multiplier to Current) annual maintenance of pavement surface, shoulders, vegetation control, ditch cleaning, culvert/underdrain (adapted from ESTIMATING COST PER LANE MILE FOR ROUTINE HIGHWAY OPERATIONS AND MAINTENANCE, Project 07-12, January 2011, Department of Civil and Environmental Engineering, University of Wisconsin) 1.50/LF estimated annual pipe maintenance 550 LF stream, MSDGC premises only. Routine inspections, enforcement of easement restrictions, repairs at 200/year (NCDENR EEP Clemson/UNCW RR ); plus open space maintenance in riparian buffer areas at 115/year (DNREC PCStrategy BMP Cost Calculations 2010). Non-Annual Operation & Maintenance Costs: Kings Run Stream Stabilization: Monitoring - Years ,640 Maintenance - Years ,181 Costs are based on Planning Study Post-construction monitoring per 401/404 regulatory requirements: Baseline Year 1 at 13,200; plus Years 2-5 at 10,000 each; all annualized over 5 years (monitoring effort is highly dependent on permit requirements) Post-construction repair, fine-tuning during Years 1-2, at 15% of construction cost, annualized over 5 years for convenience (VA Stream Guide 2004) Annual Operation & Maintenance Present Worth Parameters: Start Year: As Noted End Year: As Noted Years for Present Worth Evaluation: 30 Uniform Series Present Worth Factor: Interest Rate, %: 5.00 Gradient Series Present Worth Factor: Annual Inflation (Escalation) Rate, %: 3.50 Description Start Year End Year CSO Storage Tank, Pavement maintenance, Storm Drainage piping, Kings Run stream routine maintenance , ,382 2, , ,871 1,063,805 Non-Annual Operation & Maintenance Present Worth Parameters: Start Year: As Noted End Year: As Noted Years for Present Worth Evaluation: 5 Uniform Series Present Worth Factor: Interest Rate, %: 5.00 Gradient Series Present Worth Factor: Annual Inflation (Escalation) Rate, %: 3.50 Description Start Year End Year Annual O&M Cost at Start Year Annual O&M Cost at Start Year Annual O&M Cost at End Year Annual O&M Cost at End Year Annual Incremental Increase Annual Incremental Increase Present Worth of Constant O&M Present Worth of Constant O&M Present Worth of Incremental O&M Present Worth of Incremental O&M TOTAL PRESENT WORTH OF O&M TOTAL PRESENT WORTH OF O&M Kings Run stream non-routine monitoring & maintenance ,821 40,169 1, ,427 13, ,499 TOTAL PRESENT WORTH OF ANNUAL AND NON-ANNUAL O&M COSTS 1,223,304 POWER Engineers, Inc. Page 9 of 20

39 PLANNING OPINION OF PROBABLE CONSTRUCTION COST POWER Engineers, Inc. PN: PROJECT: PID : CSO 217/483 Source Control Phase B Planning - CSO Storage Tank & Stream Stabilization LOCATION: College Hill, Winton Hills Neighborhoods DATE: 10/3/2014 * Items not included in CSO 217 Storage Tank Business Case Technical SUBJECT: Alt. 2.1 Rectangular Tank, West Access & Kings Run Stream Stabilization Memorandum, Appendix C, or in Geomorphic Assessment and Conceptual QUARTER/YEAR: Q Alternatives Memorandum (Kings Run), Appendix D Item Code Description Quantity Unit Unit Costs Labor Material Equipt Sub Temp Matl. Equipt Rental Other Costs Total Unit Cost Total Item Cost Assumptions/Calcs Division 02 - Site Work and Demolition * Demo Two-Story House 3 EACH , , , Barn/shed Remove Asphalt Paving 4 CUYD Remove Sidewalks 750 SQFT , Remove Curb & Gutter 75 LNFT Remove Fence 700 LNFT , Saw Cut Asphalt 100 LNFT Remove & Reinstall Guardrail 100 LNFT , Demo - Miscellaneous 1 ACRE , , , Allowance Disconnect Existing Utilities 1 EACH SUBTOTAL 35, Division 02 - Site Preparation * Clearing & Grubbing - Trees 2.81 ACRE 2, , , , , Cut-Store-Spread Topsoil 2,415 CUYD , SUBTOTAL 36, Division 31 - Erosion Control * Stilling Basin, complete , , , Site preparation, excavation, fill, gravel bedding, 700 CY riprap, geotextile, restoration 1 EACH Rolled Erosion Control Mat SQFT , Rip Rap 6 CUYD SUBTOTAL 89, Division 31 - Earthwork * Fill w/ Site Earth 15,369 CUYD , Haul, off-site 3,912 CUYD , Fine Grade for Pavement SQFT , Fine Grade for Slopes SQFT , Excavate Soil - Bulk 7,400 CUYD , SUBTOTAL 214, Division 32 - Paving & Roadway * " Concrete Paving, Non-Reinforced 1187 SQYD , Concrete Driveway Apron 1 EACH , , , Concrete driveway apron 8" thk, no base, commercial (RS Means) Concrete Sidewalk (5") 750 SQFT , Concrete Curb & Gutter 75 LNFT , Pavement Misc. 1 LNFT , , , Allowance: striping, wheel stops, access controls SUBTOTAL 56, Division 32 - Landscaping * Seeding w/ Fertilizer & Mulch 12,400 SQYD , Landscaping Allowance 1 EACH , , , Screening, east side SUBTOTAL 34, POWER Engineers, Inc. Page 10 of 20

40 PLANNING OPINION OF PROBABLE CONSTRUCTION COST POWER Engineers, Inc. PN: PROJECT: PID : CSO 217/483 Source Control Phase B Planning - CSO Storage Tank & Stream Stabilization LOCATION: College Hill, Winton Hills Neighborhoods DATE: 10/3/2014 * Items not included in CSO 217 Storage Tank Business Case Technical SUBJECT: Alt. 2.1 Rectangular Tank, West Access & Kings Run Stream Stabilization Memorandum, Appendix C, or in Geomorphic Assessment and Conceptual QUARTER/YEAR: Q Alternatives Memorandum (Kings Run), Appendix D Item Code Description Quantity Unit Unit Costs Labor Material Equipt Sub Temp Matl. Equipt Rental Other Costs Total Unit Cost Total Item Cost Assumptions/Calcs Division 33 - Storm Sewer * Catch Basin VLF , Standard Type "P" Manhole (60" D) 75 VLF , " Water Tight MH Cover/Frame 5 EA , Concrete Headwall, 18" Opening 1 EACH , , , <= 18" Video Tape Installed Sewer 80 LNFT > 42" Pipe Leakage & Deflection Test 120 LNFT >=21" Video Tape Installed Sewers 380 LNFT Excavate Manhole 341 CUYD , Backfill Trench with CDF (Flowable Fill) 22 CUYD , Excavate Trench 1591 CUYD , Washed Gravel Bedding 127 CUYD , Machine Backfill, Tamped 729 CUYD , Gravel Backfill, Tamped 505 CUYD , Reuse, On-Site 862 CUYD , " Storm Reinforced Concrete Pipe 80 LNFT , " Storm Reinforced Concrete Pipe 260 LNFT , " Storm Reinforced Concrete Pipe 120 LNFT , ' Tall Storm Manhole Base 5 EACH , , " Top Transition Slab 5 EACH , Vac Test Manhole 5 EACH " 400# Heavy Duty Manhole Cover/Frame 5 EACH , Trench Box 2 EACH Concrete Headwall (mult. pipe opngs.) 1 EACH , , , SUBTOTAL 167, Division 33 - Water Utilities * Water Service Assembly 1 EACH , , From existing main at Winton Rd.: 450 LF 4-in. DIP, 4' deep, complete 28, w/tap, meter pit, excavation, backfill (RS Means) SUBTOTAL 28, Division 33 - Sanitary Sewer SUBTOTAL Division 33 - Gas, Electric and Communications Utilities * - Included in CSO 217 Storage Tank Business Case Technical Memorandum, Appendix C From existing pole line at Winton Rd.: 450 LF 2) 5-in. conduits, 3 ft. depth, complete w/concrete pad for utility-owned transformer, excavation, Electric Service 1 EACH , , , backfill (RS Means) From existing pole line at Winton Rd.: 450 LF 2) 4-in. conduit, complete Telco Service 1 EACH , , , w/excavation, backfill (RS Means) SUBTOTAL 49, Miscellaneous Divisions 02 to 46: Subtotal carried from CSO 217 Storage Tank Alternative Analysis Technical 1 EACH ,435, ,435, ,435, CSO Storage Tank, Complete Memorandum, Appendix C Division 35: Subtotal carried from Geomorphic Assessment and Conceptual Alternatives 1 EACH , , , Kings Run Stream Stabilization, Complete Memorandum (Kings Run), Appendix D SUBTOTAL 7,207, POWER Engineers, Inc. Page 11 of 20

41 PLANNING OPINION OF PROBABLE CONSTRUCTION COST POWER Engineers, Inc. PN: PROJECT: PID : CSO 217/483 Source Control Phase B Planning - CSO Storage Tank & Stream Stabilization LOCATION: College Hill, Winton Hills Neighborhoods DATE: 10/3/2014 * Items not included in CSO 217 Storage Tank Business Case Technical SUBJECT: Alt. 2.1 Rectangular Tank, West Access & Kings Run Stream Stabilization Memorandum, Appendix C, or in Geomorphic Assessment and Conceptual QUARTER/YEAR: Q Alternatives Memorandum (Kings Run), Appendix D Item Code Description Quantity Unit Unit Costs Labor Material Equipt Sub Temp Matl. Equipt Rental Other Costs Total Unit Cost Total Item Cost Assumptions/Calcs GENERAL CONDITIONS Percent of subtotal of above construction costs, includes bonding and 792, General Conditions 0.1 insurance SUBTOTAL 792, OPINION OF CONSTRUCTION COST - SUBTOTAL 8,712, Overhead , Profit , SUBTOTAL 10,019, Design Contingency 0.3 3,005, SUBTOTAL 13,025, Escalation to End of Construction Q ,825, TOTAL OPINION OF CONSTRUCTION COST Alternate ,850, PROJECT COST SUBTOTAL Total Opinion of Construction Cost 14,850,945 Value from above Right-of-Way 1,544,143 From ROW Calculations Right-of-Way Escalation to Start of Constructio Q ,897 Planning 0 389,200 Under Phase B Planning Task Order Planning Escalation to End of Planning 0 Under Phase B Planning Task Order Design 0 986, x^ (x = Construction Cost before escalation) for each: CSO tank + sitework, and stream stabilization Design Escalation to Start of Construction Q ,682 Pre-Construction Services , Treatment Plants, All Other Projects Street Opening Permits and Inspections 12 SQ YD 435 From CDOTE Fees Calculations Environmental Inspections 3400 LNFT 38, / linear foot of construction when w/i 100' of stream Geotechnical Report 12 Borings 49,500 Public Relations 50,000 Value based on project value (25k for 2MM) PTI , X Sanitary Sewer Construction Cost (Max 15,100) Railroad Permits 0 As Needed WPCLF Loan Origination Fees ( * All costs except Capitalized Interest) , As needed, for loans between 3,500,000 and 100,000, /404 Creeks and Outfalls 7,500 As needed permit fees Miscellaneous Costs Total 231,443 Miscellaneous Costs Escalation to End of Constr Q ,442 Capitalized Interest (0.05 * Years of Construction) ,910 Project Contingency 0.1 1,485,095 As defined from Manual Construction Services 78 Weeks 315,103 (2% pre-escalated const. cost + 700/week) x 1/number of project areas [spreadsheet tabs] Construction Services Escalation to End of Cons Q ,169 TOTAL OPINION OF PROJECT COST (Escalated to End of Project) 21,090,734 Alt. 2.1 Rectangular Tank, West Access & Kings Run Stream Stabilization De-Escalation Multiplier to 2006 Dollars PROJECT COSTS IN 2006 DOLLARS 15,846,650 POWER Engineers, Inc. Page 12 of 20

42 PID : CSO 217/483 Source Control Phase B Planning - CSO Storage Tank & Stream Stabilization 10/3/2014 Non-Annual Annual O&M Operation & Maintenance Description O&M Cost Notes Cost (Annualized) Alt. 2.1 Rectangular Tank, West Access & Kings Run Stream Stabilization Annual Operation & Maintenance Costs: Rectangular CSO Storage Tank 40,000 Pavement maintenance 545 Storm Drainage Piping 570 Kings Run routine stream maintenance 315 Annual Operation & Maintenance Costs are based on Planning Study Annual O&M from CSO 217 Storage Tank Business Case Technical Memorandum, Appendix C Cost () = 3250 SY * (0.13/SY, 2006) * ( Escalation Multiplier to Current) annual maintenance of pavement surface, shoulders, vegetation control, ditch cleaning, culvert/underdrain (adapted from ESTIMATING COST PER LANE MILE FOR ROUTINE HIGHWAY OPERATIONS AND MAINTENANCE, Project 07-12, January 2011, Department of Civil and Environmental Engineering, University of Wisconsin) 1.50/LF estimated annual pipe maintenance 400 LF stream, MSDGC premises only. Routine inspections, enforcement of easement restrictions, repairs at 200/year (NCDENR EEP Clemson/UNCW RR ); plus open space maintenance in riparian buffer areas at 115/year (DNREC PCStrategy BMP Cost Calculations 2010). Non-Annual Operation & Maintenance Costs: Kings Run Stream Stabilization: Monitoring - Years ,640 Maintenance - Years ,181 Costs are based on Planning Study Post-construction monitoring per 401/404 regulatory requirements: Baseline Year 1 at 13,200; plus Years 2-5 at 10,000 each; all annualized over 5 years (monitoring effort is highly dependent on permit requirements) Post-construction repair, fine-tuning during Years 1-2, at 15% of construction cost, annualized over 5 years for convenience (VA Stream Guide 2004) Annual Operation & Maintenance Present Worth Parameters: Start Year: As Noted End Year: As Noted Years for Present Worth Evaluation: 30 Uniform Series Present Worth Factor: Interest Rate, %: 5.00 Gradient Series Present Worth Factor: Annual Inflation (Escalation) Rate, %: 3.50 Description Start Year End Year CSO Storage Tank, Pavement maintenance, Storm Drainage piping, Kings Run stream routine maintenance , ,285 2, , ,250 1,072,127 Non-Annual Operation & Maintenance Present Worth Parameters: Start Year: As Noted End Year: As Noted Years for Present Worth Evaluation: 5 Uniform Series Present Worth Factor: Interest Rate, %: 5.00 Gradient Series Present Worth Factor: Annual Inflation (Escalation) Rate, %: 3.50 Description Start Year End Year Annual O&M Cost at Start Year Annual O&M Cost at Start Year Annual O&M Cost at End Year Annual O&M Cost at End Year Annual Incremental Increase Annual Incremental Increase Present Worth of Constant O&M Present Worth of Constant O&M Present Worth of Incremental O&M Present Worth of Incremental O&M TOTAL PRESENT WORTH OF O&M TOTAL PRESENT WORTH OF O&M Kings Run stream non-routine monitoring & maintenance ,821 40,169 1, ,427 13, ,499 TOTAL PRESENT WORTH OF ANNUAL AND NON-ANNUAL O&M COSTS 1,231,626 POWER Engineers, Inc. Page 13 of 20

43 PLANNING OPINION OF PROBABLE CONSTRUCTION COST POWER Engineers, Inc. PN: PROJECT: PID : CSO 217/483 Source Control Phase B Planning - CSO Storage Tank & Stream Stabilization LOCATION: College Hill, Winton Hills Neighborhoods DATE: 10/3/2014 * Items not included in CSO 217 Storage Tank Business Case Technical SUBJECT: Alt. 2.2 Rectangular Tank, East Access & Kings Run Stream Stabilization Memorandum, Appendix C, or in Geomorphic Assessment and Conceptual QUARTER/YEAR: Q Alternatives Memorandum (Kings Run), Appendix D Item Code Description Quantity Unit Unit Costs Labor Material Equipt Sub Temp Matl. Equipt Rental Other Costs Total Unit Cost Total Item Cost Assumptions/Calcs Division 02 - Site Work and Demolition * Demo Two-Story House 3 EACH , , , Barn/shed Remove Asphalt Paving 4 CUYD Remove Curb & Gutter 10 LNFT Remove Fence 700 LNFT , Saw Cut Asphalt 100 LNFT Remove & Reinstall Guardrail 100 LNFT , Demo - Miscellaneous 1 ACRE , , , Allowance Disconnect Existing Utilities 1 EACH SUBTOTAL 33, Division 02 - Site Preparation * Clearing & Grubbing - Trees 2.65 ACRE 2, , , , , Cut-Store-Spread Topsoil 2,320 CUYD , SUBTOTAL 34, Division 31 - Erosion Control * Stilling Basin, complete , , , Site preparation, excavation, fill, gravel bedding, 700 CY riprap, geotextile, restoration 1 EACH Rolled Erosion Control Mat SQFT , Rip Rap 18 CUYD , SUBTOTAL 85, Division 31 - Earthwork * Fill w/ Site Earth 15,069 CUYD , Haul, off-site 4,849 CUYD , Fine Grade for Pavement SQFT , Fine Grade for Slopes SQFT , Excavate Soil - Bulk 8,000 CUYD , SUBTOTAL 229, Division 32 - Paving & Roadway * " Concrete Paving, Non-Reinforced 1310 SQYD , Concrete Driveway Apron 1 EACH , , , Concrete driveway apron 8" thk, no base, commercial (RS Means) Concrete Curb & Gutter 10 LNFT Pavement Misc. 1 LNFT Allowance: striping, wheel stops, access controls SUBTOTAL 50, Division 32 - Landscaping * Seeding w/ Fertilizer & Mulch 11,520 SQYD , Landscaping Allowance 1 EACH , , , Screening, east side SUBTOTAL 32, POWER Engineers, Inc. Page 14 of 20

44 PLANNING OPINION OF PROBABLE CONSTRUCTION COST POWER Engineers, Inc. PN: PROJECT: PID : CSO 217/483 Source Control Phase B Planning - CSO Storage Tank & Stream Stabilization LOCATION: College Hill, Winton Hills Neighborhoods DATE: 10/3/2014 * Items not included in CSO 217 Storage Tank Business Case Technical SUBJECT: Alt. 2.2 Rectangular Tank, East Access & Kings Run Stream Stabilization Memorandum, Appendix C, or in Geomorphic Assessment and Conceptual QUARTER/YEAR: Q Alternatives Memorandum (Kings Run), Appendix D Item Code Description Quantity Unit Unit Costs Labor Material Equipt Sub Temp Matl. Equipt Rental Other Costs Total Unit Cost Total Item Cost Assumptions/Calcs Division 33 - Storm Sewer * Catch Basin VLF , Standard Type "P" Manhole (60" D) 75 VLF , " Water Tight MH Cover/Frame 5 EA , Concrete Headwall, 18" Opening 1 EACH , , , <= 18" Video Tape Installed Sewer 200 LNFT > 42" Pipe Leakage & Deflection Test 120 LNFT >=21" Video Tape Installed Sewers 380 LNFT Excavate Manhole 341 CUYD , Backfill Trench with CDF (Flowable Fill) 22 CUYD , Excavate Trench 1866 CUYD , Washed Gravel Bedding 142 CUYD , Machine Backfill, Tamped 917 CUYD , Gravel Backfill, Tamped 563 CUYD , Reuse, On-Site 948 CUYD , " Storm Reinforced Concrete Pipe 200 LNFT , " Storm Reinforced Concrete Pipe 260 LNFT , " Storm Reinforced Concrete Pipe 120 LNFT , ' Tall Storm Manhole Base 5 EACH , , " Top Transition Slab 5 EACH , Vac Test Manhole 5 EACH " 400# Heavy Duty Manhole Cover/Frame 5 EACH , Trench Box 2 EACH Concrete Headwall (mult. pipe opngs.) 1 EACH , , , SUBTOTAL 178, Division 33 - Water Utilities * Water Service Assembly 1 EACH , , From existing main at Winton Rd.: 450 LF 4-in. DIP, 4' deep, complete 28, w/tap, meter pit, excavation, backfill (RS Means) SUBTOTAL 28, Division 33 - Sanitary Sewer SUBTOTAL Division 33 - Gas, Electric and Communications Utilities * - Included in CSO 217 Storage Tank Business Case Technical Memorandum, Appendix C From existing pole line at Winton Rd.: 450 LF 2) 5-in. conduits, 3 ft. depth, complete w/concrete pad for utility-owned transformer, excavation, Electric Service 1 EACH , , , backfill (RS Means) From existing pole line at Winton Rd.: 450 LF 2) 4-in. conduit, complete Telco Service 1 EACH , , , w/excavation, backfill (RS Means) SUBTOTAL 49, Miscellaneous Divisions 02 to 46: Subtotal carried from CSO 217 Storage Tank Alternative Analysis Technical 1 EACH ,435, ,435, ,435, CSO Storage Tank, Complete Memorandum, Appendix C Division 35: Subtotal carried from Geomorphic Assessment and Conceptual Alternatives 1 EACH , , , Kings Run Stream Stabilization, Complete Memorandum (Kings Run), Appendix D SUBTOTAL 7,207, POWER Engineers, Inc. Page 15 of 20

45 PLANNING OPINION OF PROBABLE CONSTRUCTION COST POWER Engineers, Inc. PN: PROJECT: PID : CSO 217/483 Source Control Phase B Planning - CSO Storage Tank & Stream Stabilization LOCATION: College Hill, Winton Hills Neighborhoods DATE: 10/3/2014 * Items not included in CSO 217 Storage Tank Business Case Technical SUBJECT: Alt. 2.2 Rectangular Tank, East Access & Kings Run Stream Stabilization Memorandum, Appendix C, or in Geomorphic Assessment and Conceptual QUARTER/YEAR: Q Alternatives Memorandum (Kings Run), Appendix D Item Code Description Quantity Unit Unit Costs Labor Material Equipt Sub Temp Matl. Equipt Rental Other Costs Total Unit Cost Total Item Cost Assumptions/Calcs GENERAL CONDITIONS Percent of subtotal of above construction costs, includes bonding and 793, General Conditions 0.1 insurance SUBTOTAL 793, OPINION OF CONSTRUCTION COST - SUBTOTAL 8,725, Overhead , Profit , SUBTOTAL 10,033, Design Contingency 0.3 3,010, SUBTOTAL 13,044, Escalation to End of Construction Q ,828, TOTAL OPINION OF CONSTRUCTION COST Alternate ,872, PROJECT COST SUBTOTAL Total Opinion of Construction Cost 14,872,515 Value from above Right-of-Way 1,861,738 From ROW Calculations Right-of-Way Escalation to Start of Constructio Q ,202 Planning 0 389,200 Under Phase B Planning Task Order Planning Escalation to End of Planning 0 Under Phase B Planning Task Order Design 0 987, x^ (x = Construction Cost before escalation) for each: CSO tank + sitework, and stream stabilization Design Escalation to Start of Construction Q ,763 Pre-Construction Services , Treatment Plants, All Other Projects Street Opening Permits and Inspections 12 SQ YD 435 From CDOTE Fees Calculations Environmental Inspections 3400 LNFT 38, / linear foot of construction when w/i 100' of stream Geotechnical Report 12 Borings 49,500 Public Relations 50,000 Value based on project value (25k for 2MM) PTI , X Sanitary Sewer Construction Cost (Max 15,100) Railroad Permits 0 As Needed WPCLF Loan Origination Fees ( * All costs except Capitalized Interest) , As needed, for loans between 3,500,000 and 100,000, /404 Creeks and Outfalls 7,500 As needed permit fees Miscellaneous Costs Total 232,737 Miscellaneous Costs Escalation to End of Constr Q ,624 Capitalized Interest (0.05 * Years of Construction) ,719 Project Contingency 0.1 1,487,252 As defined from Manual Construction Services 78 Weeks 315,482 (2% pre-escalated const. cost + 700/week) x 1/number of project areas [spreadsheet tabs] Construction Services Escalation to End of Cons Q ,222 TOTAL OPINION OF PROJECT COST (Escalated to End of Project) 21,462,778 Alt. 2.2 Rectangular Tank, East Access & Kings Run Stream Stabilization De-Escalation Multiplier to 2006 Dollars PROJECT COSTS IN 2006 DOLLARS 16,126,187 POWER Engineers, Inc. Page 16 of 20

46 PID : CSO 217/483 Source Control Phase B Planning - CSO Storage Tank & Stream Stabilization 10/3/2014 Non-Annual Annual O&M Operation & Maintenance Description O&M Cost Notes Cost (Annualized) Alt. 2.2 Rectangular Tank, East Access & Kings Run Stream Stabilization Annual Operation & Maintenance Costs: Rectangular CSO Storage Tank 40,000 Pavement maintenance 545 Storm Drainage Piping 570 Kings Run routine stream maintenance 315 Annual Operation & Maintenance Costs are based on Planning Study Annual O&M from CSO 217 Storage Tank Business Case Technical Memorandum, Appendix C Cost () = 3250 SY * (0.13/SY, 2006) * ( Escalation Multiplier to Current) annual maintenance of pavement surface, shoulders, vegetation control, ditch cleaning, culvert/underdrain (adapted from ESTIMATING COST PER LANE MILE FOR ROUTINE HIGHWAY OPERATIONS AND MAINTENANCE, Project 07-12, January 2011, Department of Civil and Environmental Engineering, University of Wisconsin) 1.50/LF estimated annual pipe maintenance 400 LF stream, MSDGC premises only. Routine inspections, enforcement of easement restrictions, repairs at 200/year (NCDENR EEP Clemson/UNCW RR ); plus open space maintenance in riparian buffer areas at 115/year (DNREC PCStrategy BMP Cost Calculations 2010). Non-Annual Operation & Maintenance Costs: Kings Run Stream Stabilization: Monitoring - Years ,640 Maintenance - Years ,181 Costs are based on Planning Study Post-construction monitoring per 401/404 regulatory requirements: Baseline Year 1 at 13,200; plus Years 2-5 at 10,000 each; all annualized over 5 years (monitoring effort is highly dependent on permit requirements) Post-construction repair, fine-tuning during Years 1-2, at 15% of construction cost, annualized over 5 years for convenience (VA Stream Guide 2004) Annual Operation & Maintenance Present Worth Parameters: Start Year: As Noted End Year: As Noted Years for Present Worth Evaluation: 30 Uniform Series Present Worth Factor: Interest Rate, %: 5.00 Gradient Series Present Worth Factor: Annual Inflation (Escalation) Rate, %: 3.50 Description Start Year End Year CSO Storage Tank, Pavement maintenance, Storm Drainage piping, Kings Run stream routine maintenance , ,285 2, , ,250 1,072,127 Non-Annual Operation & Maintenance Present Worth Parameters: Start Year: As Noted End Year: As Noted Years for Present Worth Evaluation: 5 Uniform Series Present Worth Factor: Interest Rate, %: 5.00 Gradient Series Present Worth Factor: Annual Inflation (Escalation) Rate, %: 3.50 Description Start Year End Year Annual O&M Cost at Start Year Annual O&M Cost at Start Year Annual O&M Cost at End Year Annual O&M Cost at End Year Annual Incremental Increase Annual Incremental Increase Present Worth of Constant O&M Present Worth of Constant O&M Present Worth of Incremental O&M Present Worth of Incremental O&M TOTAL PRESENT WORTH OF O&M TOTAL PRESENT WORTH OF O&M Kings Run stream non-routine monitoring & maintenance ,821 40,169 1, ,427 13, ,499 TOTAL PRESENT WORTH OF ANNUAL AND NON-ANNUAL O&M COSTS 1,231,626 POWER Engineers, Inc. Page 17 of 20

47 10/3/2014 PROJECTS INFO PID : CSO 217/483 Source Control Phase B Planning - CSO Storage Tank & Stream Stabilization FT/PT Acquisition Cost Estimate FULL TAKES/PARTIAL TAKES (FT/PT) FT/PT Soft Cost Estimate FT/PT TOTAL Sub-Basin CSO Project Name TOTAL # FT/PT # of FT (potential) # of FT (acquired) FT AMV (potential) FT Acquired (actual cost) Multiplier (to FT AMV) Estimated FT Cost FT/PT Purchase Price Sub-Total Relocation Estimate PM (securing) PM (thru 2014) Appraisals (Incurred) Appraisals (Estimated) Titles (Incurred) Titles (Estimated) FT ESAs Closing Appropriation Admin Supplemental Assistance Benefits FT/PT Soft Cost Sub-Total FT/PT Total Estimated Kings Run 217 All Alts. Ph. B FT/PT , , ,216 Kings Run 217 All Alts. Ph. B Channel Easements ,000 10,000 Kings Run 217 Kings Run 217 Kings Run 217 Kings Run 217 Alt. 1.1 Circular Tank, West Access - Easmts Alt. 1.2 Circular Tank, East Access - Easmts Alt. 2.1 Rect. Tank, West Access - Easmts Alt. 2.2 Rect. Tank, East Access - Easmts ,000 10, ,000 10, ,000 10, ,000 10,000 POWER Engineers, Inc. Page 18 of 20

48 10/3/2014 PROJECTS INFO PID : CSO 217/483 Source Control Phase B Planning - CSO Storage Tank & Stream Stabilization REAL ESTATE COST ESTIMATES (FULL TAKES, EASEMENTS AND SOFT COSTS) Easement Acquisition Cost Estimate EASEMENTS Sub-Basin CSO Project Name Total # of EA # of Res EA # of Non- Res EA PERM (Residential) Sq Feet TEMP (Residential) Sq Feet PERM (Non- Res) Sq Feet TEMP (Non-Res) Sq Feet Estimated PERM Cost (Residential) Estimated TEMP Cost (Residential) Estimated PERM Cost (Non-Res) Estimated TEMP Cost (Non-Res) Estimated Combined Cost EA Purchase Price Sub-Total Kings Run 217 All Alts. Ph. B FT/PT Kings Run 217 All Alts. Ph. B Channel Easements Kings Run 217 Kings Run 217 Kings Run 217 Kings Run 217 Alt. 1.1 Circular Tank, West Access - Easmts Alt. 1.2 Circular Tank, East Access - Easmts Alt. 2.1 Rect. Tank, West Access - Easmts Alt. 2.2 Rect. Tank, East Access - Easmts , , , , , , ,501 7, ,501 42,458 39, , ,289 98, , , , , ,501 7, ,501 42,458 39, , ,289 98, , ,246 POWER Engineers, Inc. Page 19 of 20

49 10/3/2014 PROJECTS INFO PID : CSO 217/483 Source Control Phase B Planning - CSO Storage Tank & Stream Stabilization Soft Costs EA TOTAL RE TOTALS 2014 RE TOTALS 2006 NOTES Sub-Basin CSO Project Name Appraisals (Residential) Appraisals (Non-Res) Appraisal Cost Total Titles ESAs Appropriation Admin EA Soft Cost Sub-Total EA Total TOTAL Purchase Price TOTAL Soft Cost & Supplemental Assistance Benefits TOTAL RE Costs 2014 De-escalation Factor Purchase Price De-escalation Factor Soft Cost TOTAL RE Costs 2006 NOTES/ASSUMPTIONS Kings Run 217 All Alts. Ph. B FT/PT Kings Run 217 All Alts. Ph. B Channel Easements Kings Run 217 Kings Run 217 Kings Run 217 Kings Run 217 Alt. 1.1 Circular Tank, West Access - Easmts Alt. 1.2 Circular Tank, East Access - Easmts Alt. 2.1 Rect. Tank, West Access - Easmts Alt. 2.2 Rect. Tank, East Access - Easmts , ,000 10, , , , , , ,240 Assumed 75K per acre (residential/non-residential) 18, ,000 3, ,000 60,000 91, , , , , , , ,714 1, , ,000 4,000 15,450 22,951 7,501 25,450 32,951 6, , ,410 1,200 2,600 3, ,000 8,000 22, , ,246 32, , , , ,242 1, , ,000 4,000 15,450 22,951 7,501 25,450 32,951 6, , ,410 1,200 2,600 3, ,000 8,000 22, , ,246 32, , , , ,242 POWER Engineers, Inc. Page 20 of 20

50 ENVIRONMENTAL AND SOCIAL IMPACT ANALYSIS CSO 217/483 Source Control - Phase B - ALTERNATIVES ANALYSIS SUMMARY ENVIRONMENTAL IMPACT GRADE SOCIAL IMPACT GRADE Above Average Positive Impact Minor Positive Impact ANALYSIS SCORES Adjusted Environmental Impact Score (X 200) 64 Adjusted Social Impact Score (X 200) 6 IMPACT GRADING SCALE GRADE SCORE Major Positive Impact >90 Significant Positive Impact 70 to 90 Above Average Positive Impact 50 to 70 Average Positive Impact 30 to 50 Minor Positive Impact 1 to 30 Minor Negative Impact -30 to 0 Average Negative Impact -50 to -30 Above Average Negative Impact -70 to -50 Significant Negative Impact -90 to -70 Major Negative Impact <-90

51 PROJECT-LEVEL RISK REGISTER PROJECT NAME: CSO 217/483 SOURCE CONTROL PHASE B - CSO TANK AND STREAM STABILIZATION PROJECT ID: UPDATED BY: POWER ENGINEERS, INC. LAST UPDATED: AUGUST 4, 2014 IDENTIFICATION ASSESSMENT RESPONSE REPORTING ID RISK CAUSE OF RISK CATEGORY SUB CATEGORY CONSEQUENCES CONSEQUENCE RATING LIKELIKOOD OF OCCURRENCE RATING RISK SCORE RISK CLASS RISK RESPONSE PLAN Assigned To (Risk Responder) Due Date Resolved On Status ACTIONS TAKEN B.KR.1 B.KR.2 Unexpected soil conditions encountered during construction Lack of Experience with Design, Construction and Operation of Stream Improvement Projects Improper or inadequate soil assessment Lack of MSDGC staff experienced with design / construction / maintenance of non channelized streams Technical Technical Construction General Commissioning, Operation & Maintenance Causing a delay in the construction and increase to construction costs Potential schedule delays, cost escalation, exposure of MSDGC to claims, accidents, and damaged or poorly maintained facilities Medium Medium Confirm that boring locations and depths are adequate Capitalize on opportunities for learning and formal mentoring of MSDGC staff during design and construction. Assign organizational responsibility for O&M of the new facility. Identify organization or agency responsible for maintenance of stabilized stream, as may be necessary for 401/404 permit compliance Consultant 30% Design Phase Active MSDGC 30% Design Phase Active (date): (summary of action taken) B.KR.3 B.KR.4 B.KR.5 B.KR.6 B.KR.7 Impact mapped wetlands Construction in and near steep hillsides Local Resident Acceptance Late project construction completion Utility conflicts during construction Improper construction and/or restoration procedures, Instability of hillsides in project area Residents may not agree with aspects of the project Failure to monitor project construction schedule Lack of survey information, underground records and/or TV reports for utilities in the project vicinity Technical Technical Management Technical Technical Construction General Design Public Communications Construction General Construction General Status of minor wetlands impacted by construction is at discretion of regulatory agency(ies); expected procedures when completing construction in or near wetlands, if any, may lead to additional compliance requirements Very Low Inadequate design or construction procedures may lead to negative impacts during construction and possible negative impacts to the infrastructure after construction Medium Uninformed or unhappy residents may cause delays affecting construction completion schedule Late project construction completion can lead to cost overruns and possible penalties under consent decree Negative impacts to existing utilities, required modifications of proposed design, increases in construction costs, construction delays Low Clearly define on the construction documents the importance of maintaining proper construction techniques when completing work in or near mapped wetlands in the project vicinity Design elements to ensure safe construction of the project and to decrease the risk of possible infrastructure failure or damage. Include design requirements of registered geotechnical engineer with experience in Cincinnati area and knowledge of region and challenges. Conduct public outreach. Inform property owners of the project objectives to reduce stream bed and bank erosion prevent further Medium Monitor construction progress MSDGC Low Obtain detailed survey of the project area and any available utility information. Consultant 60% Design Phase Active Consultant 30% Design Phase Active MSDGC Ongoing Active 30% Design Phase / Construction Scheduling Active Consultant 30% Design Phase Active Ongoing: Continue community involvement activities (open houses, neighborhood meetings, resident engagement, fact sheets, ) B.KR.8 B.KR.9 Construction delays due to wet weather Negative impacts to private property Stream stabilization work unsafe or impractical during wet weather events/high flow events Stream stabilization work near private property could have negative physical impacts Technical Technical Construction General Construction General Increases in construction costs, construction delays Negative impacts to private property or structures Medium Low Add contingency time to the construction schedule. Time construction during expected drier time of year. Design elements to ensure safe construction of the project and decrease the risk of potential negative impacts to private property or structures. Keep construction actvities at safe distances from existing private structures. Inform property owners that the project is not intended to make improvements to private structures. Consultant 60% Design Phase Active Consultant 30% Design Phase Active Ongoing: Continue community involvement activities (open houses, neighborhood meetings, resident engagement, fact sheets, etc.) B.KR.10 B.KR.11 Increased soil erosion during stream stabilization construction Negative public relations with stakeholders Poor erosion control design or poor practices implmented by the contractor Inadequate communication / education regarding the importance of the stream stabilization and the benefits it will provide Technical Management Construction General Public Communications Loss of soil, discharge of soil laden water to downstream watershed Negative public image Low Low Ensure contractor follows best management practices and applicable permit requirements for work in a stream; provide proper construction oversight Begin communication and education with stakeholders early in the design process to minimize the possibility of a negative public reaction during construction MSDGC Start of Construction Active MSDGC 30% Design Phase Active Ongoing: Continue community involvement activities (open houses, neighborhood meetings, resident engagement, fact sheets, etc.) Form # PD-QA Page 1 of 3 June 17, 2011

52 PROJECT-LEVEL RISK REGISTER PROJECT NAME: CSO 217/483 SOURCE CONTROL PHASE B - CSO TANK AND STREAM STABILIZATION PROJECT ID: UPDATED BY: POWER ENGINEERS, INC. LAST UPDATED: AUGUST 4, 2014 IDENTIFICATION ASSESSMENT RESPONSE REPORTING ID RISK CAUSE OF RISK CATEGORY SUB CATEGORY CONSEQUENCES CONSEQUENCE RATING LIKELIKOOD OF OCCURRENCE RATING RISK SCORE RISK CLASS RISK RESPONSE PLAN Assigned To (Risk Responder) Due Date Resolved On Status ACTIONS TAKEN B.KR.12 B.KR.13 B.KR.14 Delay in obtaining the required property/easements Loss of existing channel biodiversity and habitat Increase in stream erosion and flooding during wet weather Inability to reach a property settlement with the owner, resulting in forced appropriations Construction activities in the channel Undersized upstream improvements or undersized stream stabilization design result in increased stream flows and water surface elevations Legal Technical Technical Easement Acquisition Construction General Design Property delays; increases in legal and/or appropriations fees, negative public image Temporary loss of existing channel biodiversity and habitat Increased stream erosion and flooding Medium Very Low Very Low Begin negotiations with property owners early, add contingency to project schedule and budget to account for appropriations delays Existing channel biodiversity and habitat is poor/moderate. Proposed improvements will provide opportunity for enhanced biodiversity and habitat. Minimize stream impacts during construction. Proposed stream flows for design storms will be attenuated in comparison to current conditions. Grade control structures, sized for stability at the 100 year, 24 hr storm event, are to minimize the risk of further stream incision. MSDGC / Consultant 30% Design Phase Active None N/A Watch None N/A Watch B.KR.15 B.KR.16 B.KR.17 B.KR.18 B.KR.19 Utility conflict during construction Ground water table is higher than expected during construction Construction delays due to wet weather Discovery of contaminated soil during construction Negative public relations with stakeholders Incomplete or incorrect utility information at the design phase Seasonal fluctuations in the local water table Flooding of tank excavation due to high creek levels Failure to perform an environmental phase assessment Inadequate communication / education regardingthe importance of the storage tank and the benefits it will provide Technical Technical Technical Environmental, Health & Safety Management Construction General Construction General Construction General Contamination Public Communications Construction delays; increases to construction costs Construction delays; increases to construction costs Construction delays; increases to construction costs Low Medium Medium Construction delays; increases to construction costs Low Negative public image Low Due to the project location, it is unlikely thatany major utilities will be discovered that would impede construction. Require the consultant to obtain detailed survey and utility information at the design phase. Obtain soil borings at the project site during the wet season, and / or schedule the tank to be constructed during the dry season Require contractor to submit a contingency plan in case the tank excavation becomes flooded. Add contingency to constructionschedule and budget to account for high wetweather flows. A phase I environmental assessment should be added to the design scope Begin communication and education with stakeholders early in the design process to minimize the possibility of a negative public reaction during construction Consultant 30% Design Phase Active Consultant / MSDGC 30% Design Phase /Construction Scheduling Active Consultant 60% Design Phase Active Consultant / MSDGC 30% Design Phase Active MSDGC 30% Design Phase Active B.KR.20 B.KR.21 Delay in obtaining the required easements for the tank Odor complaints Inability to reach a property settlement with the owner, resulting in forced appropriations Tank is not planned to have a cover; failure of tank flushing system; untimely draining of tank following storm events Legal Technical Easement Acquisition Design Property delays; increases in legal and/or appropriations fees, negative public image Negative public image Medium Low Begin negotiations with property owner early, add contingency to project schedule and budget to account for appropriations delays Due to the relatively remote tank location, the risk of odor complaints is limited to a few nearby properties. Remote monitoring of tank levels, draining and flushing systems and routine tank inspection following storm events will be implemented. No further action recommended at this time. MSDGC / Consultant 30% Design Phase Active None N/A Watch B.KR.22 Permit violation due to number of overflows Undersized tank design results in CSO 217 overflowing more than allowable annual CSO volume remaining Technical Design Failure to meet consent decree goals, resulting in additional resources needed to upsize necessary infrastructure Low Tank is being sized with MSD's SWMM model to provide contingency storage during the Typical Year storm, and to limit the overflow activations to the allowable CSO volume remaining during the typical year. No further action recommended at this time. None N/A Watch Form # PD-QA Page 2 of 3 June 17, 2011

53 PROJECT-LEVEL RISK REGISTER PROJECT NAME: CSO 217/483 SOURCE CONTROL PHASE B - CSO TANK AND STREAM STABILIZATION PROJECT ID: UPDATED BY: POWER ENGINEERS, INC. LAST UPDATED: AUGUST 4, 2014 IDENTIFICATION ASSESSMENT RESPONSE REPORTING ID RISK CAUSE OF RISK CATEGORY SUB CATEGORY CONSEQUENCES CONSEQUENCE RATING LIKELIKOOD OF OCCURRENCE RATING RISK SCORE RISK CLASS RISK RESPONSE PLAN Assigned To (Risk Responder) Due Date Resolved On Status ACTIONS TAKEN B.KR.23 B.KR.24 B.KR.25 Increase in upstream HGL during wet weather Increase in downstream flood levels during wet weather exacerbate problems with existing structure encroachments Undersized tank or pipe designs result in the upstream HGL being increased compared to current levels during wet weather Reduced flow velocity in channel Existing structures encroach in stream channel middle sub reach Technical Technical Technical Design Design Design Additional basement backups or upstream flooding compared to existing conditions Low Reduced flow velocity occupies larger channel cross sectional area for a given discharge rate Very Low Existing structures may be damaged during construction of stream stabilization improvements Medium Tank overflow weir is sized to pass the 100year, 24 hr storm event with nominal increase in upstream HGL compared to current conditions. Tank is in a relatively remote location, with only 2 private laterals connected in the first 1,000 ft upstream of the tank Implement bank re grading to reduce water surface elevation in lieu of buried grade control structures Limit work and specify pre construction condition assessment and/or construction phase structure monitoring, or do no work, in middle sub reach of stream None N/A Watch None N/A Watch None N/A Watch Form # PD-QA Page 3 of 3 June 17, 2011

54 Appendix B

55 METROPOLITAN SEWER DISTRICT OF GREATER CINCINNATI CSO 217/483 SOURCE CONTROL - PHASE B PLANNING ALTERNATIVES KEY PLAN OVERALL PROJECT

56 APPENDIX B METROPOLITAN SEWER DISTRICT OF GREATER CINCINNATI CSO 217/483 SOURCE CONTROL - PHASE B PLANNING ALTERNATIVE 1.1 CONCEPTUAL CIRCULAR CSO TANK SITE PLAN

57 APPENDIX B METROPOLITAN SEWER DISTRICT OF GREATER CINCINNATI CSO 217/483 SOURCE CONTROL - PHASE B PLANNING ALTERNATIVE 1.2 CONCEPTUAL CIRCULAR CSO TANK SITE PLAN

58 APPENDIX B METROPOLITAN SEWER DISTRICT OF GREATER CINCINNATI CSO 217/483 SOURCE CONTROL - PHASE B PLANNING ALTERNATIVE 2.1 CONCEPTUAL RECTANGULAR CSO TANK SITE PLAN

59 APPENDIX B METROPOLITAN SEWER DISTRICT OF GREATER CINCINNATI CSO 217/483 SOURCE CONTROL - PHASE B PLANNING ALTERNATIVE 2.2 CONCEPTUAL RECTANGULAR CSO TANK SITE PLAN

60 Appendix C

61 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning CSO 217 Storage Tank Alternative Analysis Technical Memorandum 1 CSO Storage Tank Strategy The overall strategy for providing a 1.5 million gallon (MG) combined sewer overflow (CSO) storage tank for capture and control of overflows from CSO 217 is established and defined in the wet weather improvement plan (WWIP) and subsequent supporting documents generated by Metropolitan Sewer District of Greater Cincinnati (MSDGC) and approved by the Environmental Protection Agency (EPA). The alternatives identified and evaluated in this section are specific in nature and related to the various components and options associated with a CSO storage tank. These alternatives are identified and grouped according to their function below, and evaluated in further detail in this section: Flow Control Tank Geometry Odor Control Tank Cleaning Common Elements 2 Flow Control 2.1 Existing System Description The CSO 217 regulator structure consists of an 11-feet by 14-feet concrete structure with a 90-inch circular concrete influent pipe and 90-inch circular concrete discharge pipe. Dry weather sanitary flow exits the side of the main regulator chamber through a 3-feet wide by 15-inch high passage from the main flow channel invert into a separate chamber. The passage is equipped with a regulator gate that operates mechanically on a float system that is tied hydraulically to the 90-inch discharge pipe. The downstream side of the regulator chamber is equipped with a 10-inch tall diversion dam. Dry weather flow exits the chamber into a 27-inch circular combined sewer. Under normal dry weather conditions, flow enters the chamber through the 90-inch influent sewer and is diverted by the dam through the open regulator gate and into the 27-inch combined sewer. Under wet weather conditions, combined sewer flows in excess of the 27-inch combined sewer system capacity pass overtop the diversion dam into the 90-inch discharge pipe. The flow is conveyed approximately 20 feet through the 90-inch discharge pipe where it exits an existing headwall into the Kings Run creek. Page 1 of 37 AECOM 10/3/2014 Draft Rev. 2

62 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning 2.2 Proposed System Description The Lower Mill Creek Partial Remedy (LMCPR) Study Report, 2012 indicates the 1.5 MG capacity CSO 217 storage tank is to hold the CSO 217 overflows and release them back into the combined sewer once capacity is available following storm events. The hydraulic Stormwater Management Model (SWMM) provided by MSDGC further indicates how the proposed configuration was envisioned to be operated Figure 2-1 is a screen capture from hydraulic model provided by others, depicting the proposed storage tank system improvements evaluated in the LMCPR. The proposed arrangement includes a new 90-inch CSO 217 overflow pipe from the 1.5 MG storage tank. The storage tank underdrain is proposed to be pumped at 4.64 CFS to an existing manhole on the 27-inch combined sewer downstream of the CSO 217 regulator. The storage tank is equipped with an overflow pipe to the creek that will discharge flows in events that produce volume in excess of the 1.5 MG storage tank capacity. This configuration represents a gravity-in, pumped-out configuration. CSO Tank Discharge MH Ex. 27-inch Combined Sewer Underflow Ex. 27-inch Combined Sewer 90-inch CSO 217 Discharge 4.64 CFS Pumped CSO Tank Discharge 1.5 MG CSO Tank CSO Tank Overflow to Creek Figure 2-1: Screen Capture of Proposed Storage Tank Improvements from MSDGC SWMM Model 2.3 Flow Control Alternatives There are three alternatives for providing flow control to in-system CSO storage facilities. The subsections below describe each flow control alternative. Page 2 of 37 AECOM 10/3/2014 Draft Rev. 2

63 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning Gravity-in/Gravity-out Figure 2-2 illustrates a gravity-in/gravity-out configuration. This configuration operates hydraulically without the aid of pumps. The available elevation difference between the upstream sewers and the downstream proposed storage tank is used to size the tank footprint for the required storage volume. Such tanks are usually constructed in the ground to accommodate this configuration. Storage Basin Figure 2-2: Gravity In/ Gravity Out Flow Configuration In the case of CSO 217, the proposed storage tank location and existing system configuration provides approximately 17+/- feet of elevation difference that can be used for CSO storage sizing. Preliminary analysis of the proposed site and hydraulics indicates that a gravity-in/gravity-out configuration is feasible for the CSO 217 storage tank in either circular or rectangular geometry. The gravity-in/gravity-out configuration generally represents the lowest overall lifecycle cost alternative as capital costs associated with pumps are avoided and annual operating power and maintenance costs are also not incurred. Following a wet weather event in which the tank retains overflows, a control valve is opened on the drain line to dewater the tank back into the existing sewer system. Overall risk is minimized with this configuration since the existing collection and overflow system continue to operate similarly to current conditions Gravity-in/Pumped-out Figure 2-3 depicts the gravity-in/pumped-out configuration. In this configuration, CSO flows are diverted by gravity into the storage tank during wet weather events. Following the wet weather event, the tank is emptied or dewatered with the use of pumps. This configuration generally dictates an in-ground system to capture and store flows from the existing underground collection system. Since the tank will be dewatered by pumps, the tank footprint is less restrictive than gravity-in / gravity-out configurations as the depth can be adjusted within reasonable hydraulic limits. Storage Basin P Figure 2-3: Gravity In/ Pump Out Flow Configuration The gravity-in/pumped-out configuration almost always represents a higher cost alternative over the life cycle when compared to gravity-in/gravity-out configuration due to the need for pumps and associated appurtenances. The main difference in costs is directly attributed to the capital and operational and Maintenance (O&M) costs of the pumps. Overall risk is fairly low with this configuration since the CSO Page 3 of 37 AECOM 10/3/2014 Draft Rev. 2

64 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning capture functions similarly to the existing system. The primary risk is associated with tank dewatering due to pump failure or malfunction. This is usually minimized by providing pumping redundancy and a backup power source Pumped-in/Gravity-out Figure 2-4 illustrates the pumped-in/gravity-out configuration. Under this scenario, CSO flows are pumped into the storage tank during wet weather events and then drained back into the existing system by gravity following the event. This configuration requires a separate pumping station to receive the CSO flows and large pumps sized to handle peak flow conditions. Because of the highly variable flow conditions in combined sewers, these influent pumps are usually equipped with variable frequency drives to handle the wide range of flows and to reduce pump cycling. One potential advantage with this arrangement is that the tank can be built at or above grade. At-grade tanks can offer some cost advantages associated with reduced excavation and less costly tank materials such as steel or prestressed concrete systems. P Storage Basin Figure 2-4: Pump In/ Gravity Out Flow Configuration This configuration typically represents the highest overall cost and the highest overall risk when compared to the other two flow control configurations. The higher cost is attributed to the separate, large pumping station and associated O&M costs. The lower cost above-ground tank can offset a portion of the initial pumping station capital cost but quickly surpasses the other two configurations in life cycle costs due to the added operational and maintenance costs associated with the large pumps. Also, some municipalities do not desire above-ground CSO storage tanks in residential areas due to their visibility. The higher risk is of this configuration is associated with pump size selection and operation. Undersized pumps can result in CSO discharges to the creek during smaller events when tank capacity remains available. Oversized pumps can result in higher power consumption and reduced pump life. Also, pump failures can result in CSO discharges to the creek when tank capacity is available. These risks can be managed by performing additional flow monitoring and hydraulic modeling to optimize pump selection along with providing separate low and high capacity pumps with redundancy and a backup power source. 2.4 Flow Control Evaluation and Recommendation Table 2-1 provides a comparison of the relative advantages and disadvantages of the three flow configuration evaluated for the CSO 217 storage tank. Table 2-1: Flow Configuration Advantages and Disadvantages Flow Control Configuration Advantages Disadvantages Gravity-in / Gravity-out Lowest life cycle cost Does not alter existing system hydraulics Tank footprint area is dictated by available hydraulic head Page 4 of 37 AECOM 10/3/2014 Draft Rev. 2

65 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning Flow Control Configuration Advantages Disadvantages Gravity-in / Pumped-out Pumped-in / Gravity-out Least visual impact with tank constructed in-ground Minimal equipment O&M Low overall risk Does not alter existing system hydraulics Deeper configurations can be used to reduce footprint area Least visual impact with tank constructed in-ground Tank can be constructed above-ground using costsaving materials and construction techniques Deeper configurations can be used to reduce footprint area Tank dewatering can be done by gravity In-ground configuration requires cast-in-place construction Increased O&M related to pumped tank dewatering Pump failure could result in tank not being ready for next storm event In-ground configuration requires cast-in-place construction Highest life cycle cost Tank visibility may cause public resentment Requires large pump station to handle peak flows high cost Carries highest risk of overflows to creek due to inadequate pump capacity or failure (i.e. some high intensity storms may result in overflows to creek even when storage tank capacity is available Preliminary analysis of the site, existing combined sewer system and hydraulics indicate that the selected CSO storage tank location can be designed to operate under the gravity-in/gravity-out scenario. Since this flow control configuration offers the best overall life cycle cost and reduces the risk of overflows to the creek, it is recommended that the CSO 217 storage tank be designed in the gravity-in/gravity-out configuration. Should unanticipated problems arise during preliminary design, this configuration could be readily adjusted to the next favorable flow control alternative of gravity-in/pumped-out. 3 Tank Geometry Two tank geometric configurations were evaluated based on available area on the proposed CSO 217 storage tank site. Preliminary analysis indicates the site will accommodate both circular and rectangular tank configurations based on the depth and footprint area requirements of the gravity-in/gravity-out flow control arrangement. Each arrangement is described in further detail in the following subsections. The main factors associated with tank geometry preference include: Concrete and Material Cost; Stress Distribution on the Tank Walls; Uplift Restrain System Costs; Tank Formwork and Constructability Costs; Required Tank Footprint; Page 5 of 37 AECOM 10/3/2014 Draft Rev. 2

66 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning Compartmentalization; and Ability to Retrofit a Cover 3.1 Circular The proposed circular tank configuration selected for the gravity-in/gravity-out operation consists of a tank with an inside diameter of 140 feet and a full side water depth of approximately 16.5 feet at the edge. The tank bottom would be an inverted cone with a 3.2% slope from the center to a sloped perimeter channel to facilitate gravity draining and solids removal. This configuration provides a nominal storage capacity of 1.5 million gallons. Figure 3-1 presents a process flow diagram and Figure 3-2 provides a conceptual site plan for the circular cast-in-place storage tank. Wet weather overflows from the existing CSO 217 structure would enter the tank from the side through a 90-inch circular conduit. Wet weather events up to the provided storage capacity would be held in the tank until capacity is available in the existing dry weather 27-inch combined sewer. Following the storm event, the tank would be drained from the perimeter sump, through an 18-inch drain pipe to the existing 27-inch combined sewer. Storm events in excess of the provided storage capacity will overflow a 60-feet long weir along the inside perimeter of the tank. Overflows will be conveyed through a 90-inch diameter overflow conduit to a headwall structure where it will discharge into the creek. Table 3-1 includes general advantages and disadvantages associated with the circular storage tank design. Table 3-1: Circular Storage Tank Advantages and Disadvantages Advantages Requires less construction material Accommodates multiple tank roof/cover arrangements Horizontal stresses are uniform Disadvantages Tank formwork is more costly than rectangular tank Does not facilitate compartmentalization Higher uplift restraint costs than rectangular tank Page 6 of 37 AECOM 10/3/2014 Draft Rev. 2

67 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning Figure 3-1: Circular Tank Process Flow Diagram Page 7 of 37 AECOM 10/3/2014 Draft Rev. 2

68 METROPOLITAN SEWER DISTRICT OF GREATER CINCINNATI CSO 217/483 SOURCE CONTROL - PHASE B PLANNING ALTERNATIVE 1 CONCEPTUAL CIRCULAR CSO TANK SITE PLAN

69 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning 3.2 Rectangular The proposed rectangular tank configuration selected for the gravity-in/gravity-out operation is 178 feet wide by 104 feet long with a full side water depth of approximately 16 feet at the edge. The tank bottom would be flat with a 2.0% slope to the sump to facilitate gravity draining and solids removal. This configuration provides a nominal storage capacity of 1.5 million gallons. Figure 3-3 presents a process flow diagram and Figure 3-4 provides a conceptual site plan for the rectangular cast-in-place storage tank. Wet weather overflows from the existing CSO 217 structure would enter the tank from the side through a 90-inch circular conduit. Wet weather events up to the provided storage capacity would be held in the tank until capacity is available in the existing dry weather 27-inch combined sewer. Following the storm event, the tank would be drained from a sump at the edge of the tank, through an 18-inch drain pipe to the existing 27-inch combined sewer. Storm events in excess of the provided storage capacity will overflow a 104-feet long weir into an 8 feet wide overflow channel. Overflows will be conveyed through a 90-inch diameter overflow conduit to a headwall structure where it will discharge into the creek. Figure 3-4 depicts a conceptual site plan for the rectangular CSO storage tank and ancillary items. Table 3-2 provides some general advantages and disadvantages associated with rectangular storage tank design. Table 3-2: Rectangular Storage Tank Advantages and Disadvantages Advantages Expandability Constructability Ability to compartmentalize Disadvantages Higher concrete and reinforcement cost Larger footprint Difficult to retrofit with cover Page 9 of 37 AECOM 10/3/2014 Draft Rev. 2

70 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning Figure 3-3: Rectangular Tank Process Flow Diagram Page 10 of 37 AECOM 10/3/2014 Draft Rev. 2

71 ALTERNATIVE 2 CONCEPTUAL RECTANGUAL CSO TANK SITE PLAN

72 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning 3.3 Tank Geometry Recommendation The advantages of either circular of rectangular tank configuration is largely dependent upon the overall site conditions as well as whether the tank is required to have a cover. Since there is no clear advantage for eliminating one configuration, both the rectangular and circular configuration are carried forward and presented in the lifecycle cost evaluation for further comparison in conjunction with the recommended stream restoration and site improvements. 4 Odor Control The two primary components of odor control include tank covers and air treatment systems. Tank covers provide containment of odors inside the CSO tank while odor control systems provide an enhanced level of odor control by scrubbing or treating odors and discharging the treated air into the atmosphere. 4.1 Tank Covers In addition to providing odor containment, tank covers provide secondary benefits in terms of public safety, reduction in rainfall accumulation inside the tank, and aesthetics. Some of the disadvantages associated with tank covers include restricted personnel access for O&M as well as visual inspection limitations. A variety of tank cover options are available for each tank geometric configuration. Figures 4-1 through 4-5 illustrate some of the various cover configurations available for each type of tank configuration Circular Tanks Figure 4-1: Aluminum Geodesic Dome Cover Page 12 of 37 AECOM 10/3/2014 Draft Rev. 2

73 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning Figure 4-2: Concrete Flat Cover Figure 4-3: Concrete Dome Cover Page 13 of 37 AECOM 10/3/2014 Draft Rev. 2

74 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning Rectangular Tanks Figure 4-4: Aluminum Flat Panel Figure 4-5: Concrete Flat Slab Page 14 of 37 AECOM 10/3/2014 Draft Rev. 2

75 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning There are three storage basin cover configurations to consider: A low-profile (such as a dome) or flat cover over the entire storage basin at or near finished grade A high profile cover consisting of a superstructure or building over the entire storage basin A combination of a superstructure over the tipping bucket end of the storage basin and a flat cover over the rest of the storage basin. Each storage basin cover configuration has relative advantages and disadvantages as indicated in Table 4-1. Table 4-1: Advantages and Disadvantages of Storage Basin Cover Configurations Cover Configuration Advantages Disadvantages Low-Profile or Flat Cover High Profile Cover Combination of Flat and High Profile Covers Least cost Least visual impact Minimal confined space entry for routine O&M Water monitors can be used to supplement tipping buckets for storage basin cleaning Easy to visually inspect storage basin Cover can be provided with architectural features to enhance aesthetics Water monitors may be used to supplement tipping buckets for storage basin cleaning (limited) Moderately easy to visually inspect storage basin The high end of the cover can be provided with architectural features to enhance aesthetics Water monitors cannot be used to supplement tipping buckets for storage basin cleaning Numerous access hatches required to allow visual inspection of storage basin Relatively high cost Confined space entry procedures may be required for entry Increased ventilation required for personnel entry Dewatering pump removal more difficult Highest cost alternative Access hatches required to allow visual inspections of flat-covered portion of storage basin Increased ventilation required for personnel entry Higher loads from wall of the high profile section on the flat portion There are many variations of construction materials to consider for the three storage basin cover configurations, including: Cast-in-Place Concrete Precast Concrete Panels Aluminum Steel Page 15 of 37 AECOM 10/3/2014 Draft Rev. 2

76 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning Fiber Reinforced Plastic (FRP) Each of these materials of construction has relative advantages and disadvantages as indicated in Table 4-2. Table 4-2 Advantages and Disadvantages of Storage Basin Cover Materials Material Advantages Disadvantages Cast-in-Place Concrete Pre-cast Concrete Panels Double Tees Aluminum Flat Panels Flat Panels with Aluminum Trusses Steel Trusses Steel Deck Composite Deck Concrete Deck FRP Flat Panels Flat Panels with Trusses Storage basin can be partially or completely buried Materials readily available Panels removable for removal of equipment Greater durability than cast-inplace concrete Low dead loads on storage basin structure Easy to remove panels for equipment access Can be made air tight with gasket materials For truss supported system, no interior columns required Standard trusses readily available Lightweight and easy to remove panels for equipment access Corrosion resistant Requires columns in storage basin for support Openings for equipment access are permanent and non-removable High dead loads on storage basin structure Joint sealant required between panel End supports required High dead loads on storage basin structure Specialty suppliers Need for columns in storage basin (for flat panels) Unauthorized removal of panels for re-sale Openings for equipment access are permanent and not easily removable Ongoing maintenance (coating) of steel components Without truss support, interior columns needed for support UV degradation a concern if not coated UV coating subject to ongoing maintenance Specialty suppliers Budgetary construction cost estimates for the cover systems presented above range from approximately 500,000 to 2,000,000 for a 1.5 MG storage tank. The cost of providing a tank cover is dependent upon the intended purpose of the cover as well as the selected tank geometry. In general, aesthetics, accessibility and rectangular tank geometry are factors that drive tank cover costs to the higher end of the spectrum. 4.2 Odor Treatment Systems Odor treatment systems provided an added level of odor control to tank covers. Odor treatment systems generally consist of blowers, air conduits, and some type of media vessel where odors are removed from the air prior to discharge into the atmosphere. The primary advantage of odor treatment systems for CSO storage facilities is that they are highly effective at removing odors in both urban and commercial settings where the public is likely to come into close contact with the odors. The disadvantages are that they require a tank cover, carry significant capital costs, and are O&M intensive processes. Proven Page 16 of 37 AECOM 10/3/2014 Draft Rev. 2

77 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning technologies for the control of odorous air emissions from wastewater collection systems along with their respective budgetary capital and annual O&M costs include: Chemical wet scrubbers, 300,000 capital cost, 200,000/year O&M cost; Activated carbon, 150,000 capital cost, 50,000/year O&M cost; Biofilters, 300,000 capital cost, 100,000/year O&M cost; Biotrickling filters., 500,000 capital cost, 100,000/year O&M cost Chemical Wet Scrubbers Chemical scrubbers using sodium hypochlorite (bleach) and sodium hydroxide (caustic) can provide odor treatment. The overall odor removal by chemical scrubbers is expected to be between 80 90%. The main disadvantage of chemical wet scrubbers for odor control is the consumption of corrosive chemicals which can lead to high operational and chemical waste disposal costs. Restrictive chemical handling requirements are required for the corrosive and hazardous chemicals. Another significant disadvantage is their complexity due to the number of components of the major equipment, including chemical metering pumps, recirculation pumps, ph probes, oxidation-reduction potential probes with controllers, and water softeners. Sodium hypochlorite has a limited effective storage life and may have diminished potency when it is needed Activated Carbon Activated carbon has a high surface-to-volume ratio, providing a large amount of surface area for odors to be adsorbed, which makes activated carbon a powerful adsorbent. The activated carbon adsorbs a wide variety of odorous compounds including H 2 S and organic compounds. Carbon systems can be operated remotely and unattended, except for routine maintenance visits. Once the media capacity is reached, no further treatment is provided and breakthrough of odor occurs which will require media replacement. This technology is widely used to treat low levels of H 2 S. To avoid freezing problems during cold weather, activated carbon systems are typically enclosed in a structure which requires heating and lighting systems Biofilters Biofilters are an odor treatment technology involving physical adsorption, aqueous absorption and bacterial oxidation of odorous compounds. Fundamentally, a biofilter is a box filled with a media (such as soil, compost, and inorganic substrate) to support the growth of bacteria which metabolize odorous compounds present in the foul air stream. Biofilters have been used to treat hydrogen sulfide in wastewater treatment plants and sanitary collection systems. Biofilters effectively treat H 2 S, organic reduced sulfur compounds and volatile organic compounds (VOCs) when contaminant loadings are within the limits of the biofilter treatment capacity. Biofilters require a continuous source of odors or food to sustain the bacteria grown on the media. During dry weather when the tank is empty, the biofilter may need to be fed with a source of carbon to keep it viable when needed during a wet weather event Biotrickling Filters Biotrickling filters are based on aqueous absorption and bacterial oxidation of the odorous contaminants. Odorous air is drawn into the system and passed through the bio-bed packed with high-surface-area synthetic media where microorganisms grow and biodegrade the odorous contaminants. In contrast to biofilters, where irrigation is periodic, water is continuously distributed over the top of the packing media in biotrickling filters. Biotrickling filters are only suitable for air stream containing high concentration (>30 ppm) of H 2 S. Biotrickling filters also require a continuous source of odors or food to sustain the bacteria Page 17 of 37 AECOM 10/3/2014 Draft Rev. 2

78 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning grown on the media. During dry weather when the tank is empty, the biotrickling filter may need to be fed with a source of carbon to keep it viable when needed during a wet weather event 4.3 Odor Control Recommendations Preliminary analysis of the site, existing combined sewer system and condition of the existing stream lead to a recommendation that the added cost of odor control provisions is not warranted for the CSO 217 storage tank. The tank location is proposed adjacent to the existing remotely located CSO 217 with some history of odor complaints; it is anticipated that a new CSO storage structure with a proper cleaning system and timely dewatering will not create new odor concerns. In fact, the net change associated with a new CSO storage structure will significantly reduce the discharge of pollutants to the creek thus improving water quality and reducing the potential for odors from the creek. Structural design of the tank can accommodate loads associated with a cover such that a retrofit cover may be installed if odor concerns become a problem in the future. Tank cover retrofit requires less structural modifications with the circular tank option. 5 Tank Cleaning Tank cleaning is an important factor in maintaining a CSO storage tank. Routine cleaning of CSO tanks following an event helps prevent the buildup of debris and corrosive substances while reducing the potential for odors. Whether or not a cover and odor control equipment is provided, a tank cleaning system should be provided to flush contaminants into the sewer and reduce the potential for odor to occur. There are two basic types of tank cleaning equipment: Flushing Systems: Flushing systems are typically automated systems that use either tipping buckets or reservoirs filled with water that are released at key locations in the tank. The release of the flushing water works in conjunction with the tank geometry and floor slope to create a wave of high energy that scours the bottom of the tank, conveying grit and debris to the tank drain sump. Flushing systems can be designed to use either potable water or even CSO water. The quantity of water needed is minimal (< 5,000 gallons/flush) and can be supplied through a typical potable water connection, as the water reservoirs can be filled slowly over several hours. Automatic flushing systems are available for both circular and rectangular tank configurations. o Example radial tank flushing system Page 18 of 37 AECOM 10/3/2014 Draft Rev. 2

79 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning o Example tipping bucket system o Example flushing gate system Water Monitors: Water monitors (or water cannons) are high pressure nozzles mounted above the tank. The position and number of monitors is determined based on the size of the tank to provide overlap such that complete cleaning of the tank can be accomplished. Water monitors can either be manual (individually operated by hand) or automated. Water monitors require a large potable water service in order to supply the large volume of water needed to flush the tank, approximately 600 gpm at 100 psi per monitor. Additionally they require break tank and booster pumping system to operate the monitors. o Example water monitor For the proposed 1.5 MG CSO 217 storage tank, water monitors are more costly both in terms of initial cost and life cycle cost due to the larger water service piping and break tank/pumping equipment. Operationally, water monitors also consume significantly more water per cleaning, as much as 10 times or more volume, when compared to tipping buckets. Both systems require additional provisions such as piping insulation and heat tracing to protect against freezing during cold weather. The following subsections provide additional descriptions of the flushing systems for each tank geometry. Page 19 of 37 AECOM 10/3/2014 Draft Rev. 2

80 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning 5.1 Circular If a circular storage tank configuration is selected, the use of a center-mounted, radial tank flushing system is proposed. Storm water will be used as the primary source of flushing water. If requested, provisions will be made to fill the flushing system with potable water from a protected water source to allow for multiple tank flushes between wet weather events. To accommodate the radial flushing system in a circular tank, the bottom of the tank is shaped as an inverted cone with a perimeter channel that drains to a single perimeter sump. Tank floor slopes must be based on the flushing distance and the flushing tank volume as recommended by the flushing system manufacturer. Manufacturer s recommended tank sump volumes and depths should also be used. Manually operated water monitors (cannons) can also be provided for spot cleaning the tank, if desired. A minimum of three water monitors, equally spaced, should be provided for a circular tank configuration. When flushing gates are provided, the water monitors may be used to fill the radial tank flushing system. 5.2 Rectangular If a rectangular storage tank configuration is selected, the use of flushing gates is the preferred tank cleaning method. Tipping buckets are an alternative technology that can be installed if operation staff prefers. When flushing gates are installed, storm water will be used as the primary source of flushing water. Provisions should be made to fill the flushing tanks with potable water from a protected water source to allow for multiple tank flushes between wet weather events when storm water is not available. Tank floor slopes should be based on the flushing distance and the flushing tank volume as recommended by the flushing gate manufacturer. Manufacturer s recommended tank sump volumes and depths should be used. Manually operated water monitors can also be provided for spot cleaning the tank. A minimum of four water monitors, equally spaced, should be provided for a rectangular tank configuration. When flushing gates are provided, the water monitors may be used to fill the flushing tanks behind the flushing gates. 5.3 Tank Cleaning Recommendations Tank flushing systems present the lowest cost alternative while achieving the overall tank cleaning objectives. A tank flushing system which can be remotely operated and uses storm water as the primary flushing water source is recommended. Provisions to fill the flushing system with potable water to clean the tank between wet weather events are also recommended. At a minimum one yard hydrant or water monitor should be provided to perform additional, spot cleaning. 6 Common Elements 6.1 Access Accessibility to each tank site during construction, operation, and maintenance must be considered. The subsections below provide guidance on civil components for various construction periods and operation activities. 6.2 Construction Access Construction phase site access should be designed so that two-way traffic can be maintained. In the event that two-way traffic cannot be maintained along the entire access road length, provide intermediate widened lanes at 500-foot maximum spacing to provide passing points. Page 20 of 37 AECOM 10/3/2014 Draft Rev. 2

81 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning 6.3 Operation and Maintenance Access A paved access road around the tank perimeter should be provided and should have radii sufficiently large to accommodate vacuum truck access. Additionally, at a minimum, gravel access paths to all sewer access structures should be provided. The diversion structure should be oriented so that vacuum trucks can access all downstream hatches for maintenance purposes. Accommodations for maintenance vehicles up to 35 feet in length and 8 feet wide are required at the storage tank, diversion structures, and other structures determined during final design. 6.4 Utilities Remote storage facilities require a number of site utility connections including: Potable water Natural gas (optional) Electric can also be used for building heating in lieu of natural gas SCADA Communications fiber optics, telephone, telemetry 6.5 Hydraulic Structures and Weir Hydraulic structures are required to connect influent, overflow, bypass, and drain piping to the storage tank. In total, three to five hydraulic structures and/or manholes are anticipated depending on the selected tank configuration and layout. In addition, a baffled weir will allow overflows in excess of 1.5 MG to discharge into the creek while trapping floatables in the tank. The floatables will then return to the combined sewer through the tank drain piping during tank dewatering. 6.6 Process Valves and Gates Eccentric plug valve - An actuated eccentric plug valve will be required in gravity dewatering scenarios to control the amount of flow released from the tank to the receiving sewers. Control will be based on downstream flow monitoring instruments. Stainless steel slide gates Motor-actuated slide gates will be required for flow bypass and structure isolation. 6.7 Flow meter Magnetic or Doppler flow meters shall be used to measure flows. Flow measurements include tank dewatering rate and City water supply rate. 6.8 Screening A screening system will be provided to collect or convey solids through the wastewater collections system as much as possible to limit remote maintenance operations. Screening solutions can be installed on the overflow to the creek, on the tank influent, or within the tank itself. It is recommended that 1.5 bar screens be placed ahead of the overflow pipes within the tank walls. 6.9 Dewatering A dewatering system should be designed to allow system operators to discharge the contents of the tank to the interceptor at a controlled rate. An actuated plug valve, installed in an underground valve vault, should be used to control the rate of flow. A magnetic flow meter installed upstream of the dewatering valve will allow the flow rate to be monitored and/or controlled. Page 21 of 37 AECOM 10/3/2014 Draft Rev. 2

82 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning A level instrument installed in the receiving sewer downstream of the tank dewatering sewer connection would allow operators and/or the control system to determine if there is available capacity. This level indication will be used to control the rate at which the tank dewatering valve is opened, so the interceptor does not become surcharged. Facility design should provide the ability to dewater the tank over a nominal 24 hour period. Actual dewatering will be based on the available capacity in the receiving sewers Controls & Monitoring The storage tank facility should be provided with a master station programmable logic controller (PLC) installed inside the Operations Building. The PLC will serve the following functions. Monitor signal inputs and outputs (I/O) from the following devices: Field instruments: flow meters and level indicators Door intrusion alarm switches Valve and gate actuators limit switches Tank cleaning system Tank pumps (if provided) Cleaning system booster pumps (if provided) Odor control system (if provided) Provide remote control of: Valve and gate actuators Tank pumps, if provided. Odor control system, if provided. Provide CSO volume capture and recording capabilities of all CSO discharge events Electricity A single source of 3-phase electric power is recommended to be provided at the tank site. Backup power generation is not recommended since the tank is proposed to fill and drain by gravity. Without backup power, functional losses are limited to tank draining, tank flushing, and flow monitoring. Since these functions can be performed manually and the loss of these functions does not prevent the tank from capturing CSO per normal operation, the consequence and subsequent risk of a power failure are low. Therefore the added cost of providing backup power generation is not warranted. Design the main circuit breaker, 480V feeder circuit breakers, and motor starters to be installed in one continuous motor control center (MCC) type construction lineup. Electric loads associated with gravity feed and gravity discharge tank alternatives may allow the MCC to be eliminated, and instead a simple power panel be provided. As the design progresses the electrical loads will be evaluated and a power solution will be provided. Page 22 of 37 AECOM 10/3/2014 Draft Rev. 2

83 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning Lighting panelboards serving 120/208V station loads shall also be integrated into the MCC lineup and not provided as stand-alone units. All MCCs will be specified with arc-resistant construction. Automatic shutters on bus bars and an arc-flash reduction maintenance switch on the main circuit breaker will be required. Both an arc-flash study and electrical system study will be specified. The arc-flash study should address all requirements of NFPA 70E. The electrical system study must consist of short circuit evaluations and circuit breaker coordination. Page 23 of 37 AECOM 10/3/2014 Draft Rev. 2

84 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning 7 Hydraulic Evaluation AECOM updated the King s Run PC-SWMM model obtained from Power Engineers to reflect both the circular and rectangular tank configurations. Table 7-1 depicts the general modeled configuration for both tanks. Prop. 18-inch DWF Line Prop. 1.5 MG Tank Ex. Diversion Structure Prop. 90-inch tank inflow Tank Overflow to Creek Prop. 12-inch tank outlet Figure 7-1: Modeled Tank Configuration in PC-SWMM In order to account for the two potential site plan and stream restoration scenarios, the circular tank was modeled at an elevation that better accommodates site access from east that would likely result in less fill material and a lower finished grade elevation when compared to that of site access from the west. The rectangular tank was then modeled at a relatively higher elevation consistent to what might be expected if site access from the west is selected. Both arrangements demonstrate that the overall hydraulic constraints associated with the site layout options provide significant flexibility for the preferred gravityin/gravity-out operational configuration while meeting the CSO capture objective. The typical year event and a number of SCS Type II 24-HR design storm events were modeled to determine the hydraulic performance of the proposed tank configurations. Table 7-1 summarizes the results for the circular tank configuration. Page 24 of 37 AECOM 10/3/2014 Draft Rev. 2

85 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning Recurrence Interval Table 7-1: Summary of Circular Tank Model Results for Various Storms Max HGL at Diversion Structure (ft) Min Freeboard at Diversion Structure (ft) Max HGL at Tank (ft) Max Tank Influent Flow (cfs) Max Tank Influent Velocity (fps) Max Flow to Creek (cfs) Max Velocity to Creek (fps) 10-YR, 24-HR YR, 24-HR YR, 24-HR YR, 24-HR Typical Year As shown in Table 7-1 a minimum freeboard (distance from the HGL to the rim elevation) of approximately 6.6 feet is obtained at the diversion structure (existing manhole ) during the Typical Year event. The 100-year, 24-hour SCS Type II storm event produced a minimum freeboard of 2.8 feet at the Diversion Structure. All of the modeled events resulted in discharge from the overflow weir, which was set at an elevation of The results for the rectangular tank configuration are provided in Table 7-2. Recurrence Interval Table 7-2: Summary of Rectangular Tank Model Results for Various Storm Events Max HGL at Diversion Structure (ft) Min Freeboard at Diversion Structure (ft) Max HGL at Tank (ft) Max Tank Influent Flow (cfs) Max Tank Influent Velocity (fps) Max Flow to Creek (cfs) Max Velocity to Creek (fps) 10-YR, 24-HR YR, 24-HR YR, 24-HR YR, 24-HR Typical Year Compared to the circular tank, the rectangular configuration yielded higher HGLs across all of the modeled storm events. This was expected, as the proposed invert of the rectangular tank and the overflow weir are higher than those proposed for the circular tank. As shown in the above table, a minimum freeboard (distance from the HGL to the rim elevation) of approximately 4.5 feet is obtained at the diversion structure (existing manhole ) during the Typical Year event. The 100-year, 24- hour SCS Type II storm event produced a minimum freeboard of 1.8 feet at the diversion. All of the modeled events resulted in discharge from the overflow weir, which was set at an elevation of A more detailed hydraulic analysis should be performed during detailed design for the selected tank and site configurations. For both tank configurations, a total of four overflow events were produced during the typical year event, resulting in approximately 11 MG of total overflow volume. The results are summarized in Table 7-3. Page 25 of 37 AECOM 10/3/2014 Draft Rev. 2

86 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning Table 7-3: Summary of Typical Year Overflow Events by Tank Configuration Typical Year Event Circular Tank Overflow Volume (MG) Rectangular Tank Overflow Volume (MG) 4/2/ /5/ /13/ /8/ Total Figure 7-2 and Figure 7-3 depict the typical year peak profiles for the circular and rectangular tank configurations, respectively. Page 26 of 37 AECOM 10/3/2014 Draft Rev. 2

87 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning Diversion Structure Circular Tank Ex. MH Figure 7-2: Typical Year Peak Profile Circular Tank Configuration Page 27 of 37 AECOM 10/3/2014 Draft Rev. 2

88 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning Diversion Structure Rectangular Tank Ex. MH Figure 7-3: Typical Year Peak Profile Rectangular Tank Configuration Page 28 of 37 AECOM 10/3/2014 Draft Rev. 2

89 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning Life Cycle Cost Estimate Cost Estimate Summary AECOM completed a Class IV life cycle cost estimate for both the circular and rectangular tank alternatives. For each configuration, the estimated costs were calculated in 2014 dollars and then deescalated to 2006 dollars for comparison with the Lower Mill Creek Partial Remedy study estimates using a factor of , as determined from MSD s online tables. After de-escalation, the estimated life cycle costs for the circular and rectangular tank configurations are 9.5 and 11.1 million dollars, respectively. Table 8-1 provides a summary of each estimate. Table 8-1: Class IV Life Cycle Cost Estimate Summary by Division Circular Tank Div Description Unit Cost Total Cost (Q1-2014) Total Cost (Q1-2014) Total Cost (2006 Dollar) Deescalation Value Division 2 - Site Work and Demolition 148, , Division 3 - Concrete 1,818,000 1,571, Division 5 - Metals 29,000 26, Division 31 - Earthwork 1,435,000 1,240, Division 33 - Utilities 636, Division 40 - Process Integration Division 46 - Water and Wastewater Equipment 265, ,000 Subtotal ,031, , ,000 2,220,000 1,918,000 41,000 36,000 1,734,000 1,498, , , , , , , , , ,000 4,346,000 5,955,000 5,145,000 Divisions 4-10: Miscellaneous Architectural 2% 101,000 88, , , Division 22 - Plumbing Systems 1% 51,000 45,000 60,000 52, Division 23 - HVAC Systems 1% 26,000 23,000 30,000 26, Division 26 - Electrical Systems 2% 101,000 88, , , Division 28 - Electronic Safety and Security Division 32 - Exterior Improvements 0.5% 2% 26, ,000 23,000 88,000 30, ,000 26, ,000 Subtotal Contractor Overhead and Profit Base Construction Cost Design Contingency 5,437,000 15% 4,697, , ,000 6,253,000 5,402,000 5,559, , ,000 7,401,000 6,394,000 2,221,000 1,919,000 75,000 75,000 65,000 65,000 8,442,000 1,621,000 55,000 55,000 Total Construction Cost 8,255,000 7,131,000 9,772,000 Real Estate Costs Administration Costs 4% 331, ,000 Project Contingency 10% 4.2% 826, , , , , , , , , ,000 3% 5% 207, , , , , ,000 8,966,000 12,286, , ,000 Construction Interest Miscellaneous Field Engineering & Inspection Capital Cost 30% 1,876,000 6,435,000 63,000 63,000 Bonding Insurance 8.2 Rectangular Tank Total Cost (2006 Dollar) Deescalation Value % 1% 10,379,000 10,614,000 Present Worth of Residual Value of Capital Cost Present Worth of Equipment Replacement Annual O&M (25-yr life expectancy) Present Worth of Annual O&M 40, ,000 40, ,000 40, ,000 35, ,000 Life Cycle Cost 10,991,000 9,495,000 12,938,000 11,142,000 Total Construction Cost The total construction cost consists of the labor, material, and mobilization costs required to construct each tank configuration, plus the contractor overhead and profit, design contingency, bonding and insurance. In accordance with MSDGC Estimating Guidelines, an overhead and profit of 15% was used, and a design contingency of 30% was applied. Bonding and insurance were estimated at 1% each. Page 29 of 37 AECOM 10/3/2014 Draft Rev. 2

90 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning 8.3 Capital Cost The capital cost consists of the total construction cost plus the cost of real estate, administration, project contingency, construction interest (escalation), miscellaneous costs, and the cost of field engineering and inspection. A real estate cost was not applied to this estimate, as it will be accounted for in the site improvement costs provided in a difference section. In accordance with standard MSDGC estimating rates, administration costs were calculated at 4% of the total construction cost, a project contingency of 10% was applied, and miscellaneous costs were assumed at 3% of the total construction cost. A construction interest or escalation factor of 4.2% was employed to match that assumed in the Lower Mill Creek Partial Remedy Study. Finally, the costs of field engineering and inspection were estimated at 5% of the total construction cost. 8.4 Life Cycle Cost To calculate the life cycle cost, the present worth of the salvage value, equipment replacement, and annual O&M costs were all added to the capital cost. To match the Lower Mill Creek Partial Remedy Study, a service life of 25 years was assumed. As requested on page 8 of the MSDGC Financial Analysis Manual dated June 2013, depreciation and residual values were omitted from the life cycle cost. In addition, the estimated service life of the instruments, valves, and screens is approximately 25 years therefore the replacement cost for these items was also omitted. The annual O&M cost was estimated at 40,000 and assumes that the basin will be cleaned 26 times a year, after each wet weather event. Monthly instrument, valve, meter, and screen maintenance is also included in the annual O&M cost estimate. 8.5 Detailed Cost Estimates Table 8-2 and Table 8-3 portray a detailed cost estimate for the circular and rectangular tank configurations, respectively. Page 30 of 37 AECOM 10/3/2014 Draft Rev. 2

91 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning Table 8-2: Circular Tank Detailed Cost Estimate Summary Div 02 Description Quantity 148,000 LS 50,000 50, ,000 44, CY 120 8,000 7,000 1,000 LF 5 5,000 5,000 1 Environmental Compliance (Silt Fence) LS 25,000 25,000 SF 60,000 52,000 Division 3 - Concrete 1,818,000 Storage Basin Temporary Seeding and Mulching 1 30,000 Base Slab , ,000 CY , , CY 1,100 55,000 48, EA 3, , ,000 EA 15,000 15,000 13,000 CCF 15,000 13, , Junction Structures on Tank Inflow 2 EA 50, ,000 87,000 CSO 217 Discharge Headwall 1 EA 25,000 25,000 22,000 29, LF 50 22, LF 100 7,000 1,435,000 Division 5 - Metals Aluminum Guard Rail Adjustable Stainless Steel Weir Plate 26,000 20,000 7,000 11,126 CY ,000 Site excavation in rock 1,963 CY 50 99,000 86,000 Temporary Excavation Support 8,500 SF , ,000 50,000 50,000 44, , , , , ,000 44,000 Geotechnical Instrumentation and Monitioring Trenching and Backfill 1 1,021 Dewatering 1 Structural Fill ALLOW LF ALLOW 982 CY 50 50, ,000 18" Conduit, Type "C" 120 LF , ,000 21,000 27" Conduit, Type "C" 600 LF , ,000 90" Conduit, Type "C" 300 LF 1, , ,000 Division 33 - Utilities Flow Control of Sewer Lines 1 Video Taping of Installed Sewers 1,020 ALLOW 100,000 LF 3 100,000 87,000 4,000 4,000 Modified Type "S" Manhole, 5-ft I.D. 4 EA 5,000 20,000 18,000 Modified Type "S" Drop Manhole, 5-ft I.D. 1 EA 7,500 8,000 7, ,000 90" Flow Control Gate 1 EA 100, ,000 18" Flow Control Gate 1 EA 10,000 10,000 9,000 Stop Logs 2 EA 50, ,000 87,000 Flushing System Hydraulic Units Flow Meter 1 EA 15,000 15,000 13,000 2 EA 20,000 40,000 35, , ,000 Bar Screen 1 EA 400, , ,000 Flushing System 1 LS 300, , ,000 Division 40 - Process Integration Division 46 - Water and Wastewater Equipment Subtotal ,240,000 97,000 Division 31 - Earthwork Site excavation 46 1,571,000 0 CY Rock Anchor Valve/Meter Vault Elevated Slab Leakage Testing of Structures 2 1,100 Walls 33 22,000 Stormwater Pollution Prevention Plan - SWPPP, NOI, & NOT 31 Total Cost (2006 Dollar) Deescalation Value Fill, Seal and Abandon Existing Sewers (12" and Larger) 05 Unit Cost Division 2 - Site Work and Demolition Clearing and Grubbing 03 Unit Total Cost (Q1-2014) Divisions 4-10: Miscellaneous Architectural 229,000 87,000 5,031,000 4,346,000 2% 101,000 88, Division 22 - Plumbing Systems 1% 51,000 45, Division 23 - HVAC Systems 0.5% 26,000 23, Division 26 - Electrical Systems 2.0% 101,000 88, Division 28 - Electronic Safety and Security Division 32 - Exterior Improvements 0.5% 2% 26, ,000 23,000 88,000 5,437,000 4,697,000 15% 816, ,000 6,253,000 5,402,000 30% 1,876,000 1,621,000 1% 1% 63,000 63,000 55,000 55,000 8,255,000 7,131,000 Subtotal Contractor Overhead and Profit Base Construction Cost Design Contingency Bonding Insurance Total Construction Cost Real Estate Costs - 4% 331, ,000 Project Contingency 10% 4.2% 826, , , ,000 Miscellaneous 3% 207,000 Field Engineering & Inspection Capital Cost 5% 413,000 10,379, , ,000 8,966,000 Construction Interest Present Worth of Residual Value of Capital Cost - - Present Worth of Equipment Replacement , ,000 35, ,000 10,991,000 9,495,000 Annual O&M Present Worth of Annual O&M (Assumed Useful Life of 25 years) Life Cycle Cost Page 31 of 37 - Administration Costs AECOM 10/3/2014 Draft Rev. 2

92 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning Table 8-3: Rectangular Tank Detailed Cost Estimate Summary Div 02 Description Quantity 173,000 LS 75,000 75, CY 120 8,000 1,000 LF 5 5,000 LS 25,000 25,000 SF 60,000 Division 3 - Concrete 2,220,000 Storage Basin - 1 Fill, Seal and Abandon Existing Sewers (12" and Larger) Environmental Compliance (Silt Fence) Stormwater Pollution Prevention Plan - SWPPP, NOI, & NOT Temporary Seeding and Mulching 1 30,000 Base Slab 31 36,000 1,498, , , ,000 5,955,000 5,145, , , CY 1,100 55, EA 3, ,000 1,000 CCF 15, EA 15,000 15,000 Junction Structures on Tank Inflow and Overflow Weir 4 EA 50, ,000 CSO 217 Discharge Headwall 1 EA 25,000 25,000 41,000 Division 5 - Metals Aluminum Guard Rail 600 LF 50 30,000 Adjustable Stainless Steel Weir Plate 104 LF ,000 1,734,000 Site excavation and Fill 12,813 CY ,000 Site excavation in rock Temporary Excavation Support Geotechnical Instrumentation 2,261 CY ,000 10,000 SF ,000 ALLOW 50,000 50, ,000 Division 31 - Earthwork 1 1,020 1 LF ALLOW ,000 1,131 CY 50 57, ,000 18" Conduit, Type "C" 160 LF ,000 27" Conduit, Type "C" 600 LF ,000 90" Conduit, Type "C" 155 LF 1, ,000 96" x 60" Conduit, Type "C" 105 LF Flow Control of Sewer Lines 1 Structural Fill 400,000 Division 33 - Utilities Video Taping of Installed Sewers ALLOW 1, , , ,000 1,021 LF 3 4,000 Modified Type "S" Manhole, 5-ft I.D. 4 EA 5,000 20,000 Modified Type "S" Drop Manhole, 5-ft I.D. 1 EA 7,500 8, , ,000 Division 40 - Process Integration 90" Flow Control Gate 1 EA 100,000 18" Flow Control Gate Stop LogsSystem Hydaraulic Flushing 1 EA 10,000 10,000 2 EA 50, ,000 Units 2 EA 15,000 30,000 Flow Meter 2 EA 20,000 40, ,000 Bar Screen 1 EA 250, ,000 Flushing Gates 8 EA Division 46 - Water and Wastewater Equipment 75,000 Subtotal CY Dewatering 46 1,918,000 Valve/Meter Vault Trenching and Backfill 40 CY and Monitioring , Elevated Slab Rock Anchor Leakage Testing of Structures 2 1,600 Walls 05 Unit Division 2 - Site Work and Demolition Clearing and Grubbing 03 Total Cost (2006 Total Cost (Q1Dollar) DeUnit Cost 2014) escalation Value ,000 Divisions 4-10: Miscellaneous Architectural 2% 120, , Division 22 - Plumbing Systems 1% 60,000 52, Division 23 - HVAC Systems 0.5% 30,000 26, Division 26 - Electrical Systems 2.0% 120, , Division 28 - Electronic Safety and Security Division 32 - Exterior Improvements 0.5% 2% 30, ,000 26, ,000 5,559,000 Subtotal Contractor Overhead and Profit 6,435,000 15% 966, ,000 7,401,000 6,394,000 30% 2,221,000 1,919,000 1% 1% 75,000 75,000 65,000 65,000 9,772,000 8,442,000 Base Construction Cost Design Contingency Bonding Insurance Total Construction Cost Real Estate Costs , , ,000 Project Contingency 4% 10% 845,000 Construction Interest 4.2% 411, ,000 Miscellaneous Field Engineering & Inspection Capital Cost 2.5% 245,000 5% 489,000 12,286, , ,000 10,614,000 - Administration Costs Present Worth of Residual Value of Capital Cost Present Worth of Equipment Replacement Annual O&M Present Worth of Annual O&M (Assumed Useful Life of 25 years) Life Cycle Cost Page 32 of 37 AECOM , ,000 35, ,000 12,898,000 11,142,000 10/3/2014 Draft Rev. 2

93 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning 9 Construction Schedule The anticipated construction schedule, shown in Figure 9-1, will be over two construction seasons. Tank construction will span a total of 18 calendar months to account for seasonal down time. Page 33 of 37 AECOM 10/3/2014 Draft Rev. 2

94 ID Task Name Duration Start Finish Predecessors 1 CSO 217 Storage Basin 435 days Wed 4/1/15 Tue 11/29/16 2 Pre-Construction 60 days Wed 4/1/15 Tue 6/23/15 3 Notice to Proceed 0 days Wed 4/1/15 Wed 4/1/15 4 Submittals 60 days Wed 4/1/15 Tue 6/23/15 5 Initial Submittals 15 days Wed 4/1/15 Tue 4/21/15 6 Remaing Submittals Submittals 45 days Wed 4/22/15 Tue 6/23/ Construction 370 days Wed 4/22/15 Tue 9/20/16 8 Mobilization and Site Clearing 10 days Wed 4/22/15 Tue 5/5/ Install Utilities for Operations Bldg 20 days Wed 5/6/15 Tue 6/2/ Construct Operations Building 60 days Wed 6/3/15 Tue 8/25/ Install Operations Building Appurtenances 40 days Wed 8/26/15 Tue 10/20/ Excavate for Storage Basin 40 days Wed 6/3/15 Tue 7/28/ Construct Influent Sewer 20 days Wed 4/22/15 Tue 5/19/ Place Pre-cast Structures 20 days Wed 5/20/15 Tue 6/16/ Construct Cast in Place Sewer Structures 30 days Wed 6/17/15 Tue 7/28/ Construct Influent Sewer 15 days Wed 7/29/15 Tue 8/18/ Construct Dry Weather Sewer 15 days Wed 8/19/15 Tue 9/8/ Construct Overflow Sewer 10 days Wed 9/9/15 Tue 9/22/ Construct Storage Basin 170 days Wed 10/21/15 Tue 6/14/16 18,12,11 20 Install Electrical, Insturmentation, and Hydraulic Undergrounds 20 days Wed 6/15/16 Tue 7/12/ Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 4/1 21 Install I&C, and Mechanical Equipment 20 days Wed 7/13/16 Tue 8/9/ Install Tank Appurtenances 30 days Wed 6/15/16 Tue 7/26/ Earth Moving Rough Grading 20 days Wed 6/15/16 Tue 7/12/ Site Lighting and Fencing 20 days Wed 7/13/16 Tue 8/9/ Construct Asphalt Road and Parking 20 days Wed 8/10/16 Tue 9/6/ Final Grading 10 days Wed 9/7/16 Tue 9/20/ Post Construction 50 days Wed 9/21/16 Tue 11/29/ Start-up & Commisioning 45 days Wed 9/21/16 Tue 11/22/16 29 Demobilization 5 days Wed 11/23/16 Tue 11/29/16 28 Task Project Summary Inactive Milestone Manual Summary Rollup Progress Project: CSO217_sch_Draft Construct Date: Wed 3/12/14 Split Milestone External Tasks External Milestone Inactive Summary Manual Task Manual Summary Start-only Deadline Summary Inactive Task Duration-only Finish-only Page 1

95 Metropolitan Sewer District of Greater Cincinnati - CSO 217/483 Source Control Phase B Planning 10 Risk Register A risk register was generated for this alternative analysis to identify and categorize the relative risks associated with the CSO 217 storage tank project, and is shown in Figure Page 35 of 37 AECOM 10/3/2014 Draft Rev. 2

96 PROJECT-LEVEL RISK REGISTER CSO 217 STORAGE TANK PROJECT NO LAST UPDATED: LAST UPDATED BY: AECOM IDENTIFICATION ASSESSMENT RESPONSE REPORTING ID RISK CAUSE OF RISK CATEGORY SUB-CATEGORY CONSEQUENCES CONSEQUENCE RATING LIKELIKOOD OF OCCURRENCE RATING RISK SCORE RISK CLASS RISK RESPONSE PLAN Assigned To (Risk Responder) Due Date Resolved On Status ACTIONS TAKEN 1 Utility conflict during construction Incomplete or incorrect utility information at the design phase Technical Construction - General Construction delays; increases to construction costs Low Due to the project location, it is unlikely that any major utilities will be discovered that would impede construction. Require the consultant to obtain detailed survey and utility information at the design phase. Consultant 30% Design Phase Active Seasonal fluctuations in the local water table 2 Ground water table is higher than expected during construction Technical Construction - General Construction delays; increases to construction costs Medium Obtain soil borings at the project site during the wet season, and / or schedule the tank to be constructed during the dry season Consultant / MSDGC 30% Design Phase / Construction Scheduling Active 3 4 Construction delays due to wet weather Discovery of contaminated soil during construction Flooding of tank excavation due to high creek levels Failure to perform an environmental phase assessment Technical Environmental, Health & Safety Construction - General Contamination Construction delays; increases to construction costs Construction delays; increases to construction costs Medium Low Require contractor to submit a contingency plan in case the tank excavation becomes flooded. Add contingency to construction schedule and budget to account for high wet weather flows. A phase I environmental assessment should be added to the design scope Consultant 60% Design Phase Active Consultant / MSDGC 30% Design Phase Active 5 Negative public relations with stakeholders Inadequate communication / education regarding the importance of the storage tank and the benefits it will provide Management Public Communications Negative public image Low Begin communication and education with stakeholders early in the design process to minimize the possibility of a negative public reaction during construction MSDGC 30% Design Phase Active 6 Delay in obtaining the required easements for the tank Inability to reach a property settlement with the owner, resulting in forced appropriations Legal Easement Acquisition Property delays; increases in legal and/or appropriations fees, negative public image Medium Begin negotiations with property owner early, add contingency to project schedule and budget to account for appropriations delays MSDGC / Consultant 30% Design Phase Active 7 Odor complaints Tank is not planned to have a cover; failure of tank flushing system; untimely draining of tank following storm events Technical Design Negative public image Low Due to the relatively remote tank location, the risk of odor complaints is limited to a few nearby properties. Remote monitoring of tank levels, draining and flushing systems and routine tank inspection following storm events will be implemented. No further action recommended at this time. None N/A Watch 8 9 Permit violation due to number of overflows Increase in upstream HGL during wet weather Undersized tank design results in CSO 217 overflowing more than 4 times per year Undersized tank or pipe designs result in the upstream HGL being increased compared to current levels during wet weather Technical Technical Design Design Failure to meet consent decree goals, resulting in additional resources needed to upsize necessary infrastructure Additional basement backups or upstream flooding compared to existing conditions Low Low Tank is being sized with MSD's SWMM model to provide contingency storage during the Typical Year storm, and to limit the overflow activations to 4 during the typical year. No further action recommended at this time. Tank overflow weir is sized to pass the 100- year, 24-hr storm event with nominal increase in upstream HGL compared to current conditions. Tank is in a relatively remote location, with only 2 private laterals connected in the first 1,000 ft upstream of the tank None N/A Watch None N/A Watch Form # PD-QA Page 1 of 1 June 17, 2011