DESIGN INFORMATION MEMORANDUM NO. 2 CENTRAL FACILITIES SITING, ALIGNMENT AND CONFIGURATION

Transcription

1 ORANGE COUNTY SANITATION DISTRICT JOB NO. I-10 REPLACEMENT OF THE ELLIS AVENUE PUMP STATION DESIGN INFORMATION MEMORANDUM NO. 2 CENTRAL FACILITIES SITING, ALIGNMENT AND CONFIGURATION REVISION: D APRIL Lake Center Drive, Suite 150 Lake Forest, CA 92630

2 JOB NO. I-10 REPLACEMENT OF THE ELLIS AVENUE PUMP STATION DESIGN INFORMATION MEMORANDUM NO. 2 CENTRAL FACILITIES SITING, ALIGNMENT AND CONFIGURATION ORANGE COUNTY SANITATION DISTRICT REVISION: D DRAFT FINAL APRIL 2004 MALCOLM PIRNIE, INC Lake Center Drive, Suite 150 Lake Forest, CA I10-Title Page-DIM2.doc TP-1

3 ORANGE COUNTY SANITATION DISTRICT JOB NO. I-10 REPLACEMENT OF THE ELLIS AVENUE PUMP STATION DESIGN INFORMATION MEMORANDUM NO. 2 CENTRAL FACILITIES SITING, ALIGNMENT AND CONFIGURATION History of Change Revision Author Date Change A Draft Malcolm Pirnie March 2003 First Submittal B Draft Malcolm Pirnie August 2003 Revised per PE 1 Workshop comments C Draft Malcolm Pirnie November 2003 Revised per September 30, 2003 Progress Meeting D Draft Final Malcolm Pirnie April 2004 Revised per OCSD review comments dated March 23, 2004 I10-Histroy of Change DIM 2.doc HOC-1 DRAFT-FINAL

4 INTRODUCTION AND SUMMARY Design Information Memorandum (DIM) No. 2, Central Facilities Siting, Alignment and Configuration identifies the alternatives considered for the proposed Ellis Avenue Pump Station (PS) based on four major site conditions, reviews each alternative with respect to several engineering and technical criteria or features, compares alternatives, and identifies alternatives as most technically feasible, moderately technically feasible, least technically feasible, or infeasible based on the engineering and technical features. In addition, the memorandum identifies project and life cycle costs for each alternative and specific engineering recommendations for the proposed pump station facilities including structure sizes, pump types, and preliminary layouts. This document will be used in conjunction with the Draft Subsequent Environmental Impact Report (EIR) prepared as part of CEQA to establish a final recommended pump station alternative. The District Board will use these two documents as well as public input to balance engineering/technical considerations, environmental considerations, and life cycle costs and to select the final pump station alternative. The pump station alternative selection by the Board will be performed at the conclusion of the CEQA process and no decisions regarding a final site will be made until that time. It should be noted that all alternatives identified could be implemented from and engineering and technical viewpoint. However, some alternatives will require more engineering and technical measures to implement than others. It should also be noted that certain engineering and technical measures may be preferable in order to avoid specific environmental impacts or to achieve public acceptance. The District Board will take these factors into consideration when making the final alternative recommendation. Based on the evaluation presented in this memorandum, the following is a summary of the technical viability of each pump station alternative: Most Technically Feasible Alternatives: Alternative G Pacific Decorating Talbert/Bushard Alternative H Methodist Church Bushard Alternative I Ellis & Bushard Two Homes ES-1

5 Moderately Technically Feasible Alternatives: Alternative D Moiola Elementary School Finch Street Alternative E Callens Ranch on Ellis Alternative J Ellis & Bushard Below-ground Alternative K Walgreens Garfield/Bushard Less Technically Feasible Alternatives: Alternative A OCSD Plant No. 1 North Corner Alternative B Commercial Park Ellis and Pacific Alternative F N Fountain Valley High School North Configuration Alternative F S Fountain Valley High School South Configuration Infeasible Alternatives: Alternative C OCSD Plant No. 1 South PROJECT DESCRIPTION Job No. I-10 Replacement of the Ellis Avenue Pump Station includes the following major components and facilities: New wastewater pumping station including dry pit submersible pumps, valves, piping, and appurtenances. New 48-inch diameter force main to convey flow from the pump station to the Plant No. 1 Headworks. New Job No. I-10 Diversion Structure on the Knott, Magnolia, or Bushard Trunk Sewers as required to divert flows to the proposed pump station. New 84-inch diameter Plant No. 1 Diversion Trunk Sewer (approximately 5,200 linear feet) to convey flow from Plant No. 1 to the existing 96-inch diameter Interplant Trunk at the intersection of Ellis Avenue and Brookhurst Street. New diversion structure located on the existing 69-inch diameter Miller Holder Trunk Sewer and a new 33-inch diameter gravity sewer (approximately 2,700 linear feet) to convey flow from the Miller Holder to the existing 36-inch Golden West Trunk Sewer. Decommissioning of the Existing Ellis Avenue Pump Station and force main. Electrical, instrumentation and control systems. Heating and ventilating systems. Plumbing systems. Miscellaneous site work ES-2

6 The project is generally located within the City of Fountain Valley except for a new diversion structure located on the existing 69-inch diameter Miller Holder Trunk and a 33-inch diameter gravity sewer between the Miller Holder and the Golden West Trunks. These facilities are located within the City of Huntington Beach. PURPOSE OF THE ELLIS AVENUE PUMP STATION The primary purpose of the proposed Ellis Avenue Pump Station is to match influent flows to the District s Plant No. 1 (P1) and Plant No. 2 (P2) build out capacities. The latest master plan projects substantial flow increases for both plants through the year New facilities, including the full secondary treatment facilities are being designed and constructed at P1 and P2 based on the projections from the Strategic Plan. When built, the new facilities will essentially use up all remaining vacant area at both plant sites. In addition, when fully built out, P2 will not be able to handle the projected average flows from its current service area. Therefore, the Ellis Avenue PS will be needed to divert some of the flows destined for P2 to P1 to match influent flows to plant capacities. A second reason for the Ellis Avenue PS is to maintain a minimum flow to P1. A minimum flow to P1 is required to provide adequate flow to the Ground Water Replenishment System (GWRS). The GWRS Project provides advanced treatment of OCSD secondary effluent and delivers the final product water for groundwater infiltration. Because of process limitations, the GWRS must be operated at a fairly constant flow rate. However, minimum diurnal flows entering P1 from its service area are much less than the required GWRS capacity. The problem is compounded by the fact that the Department of Health Services has determined that flows from the SARI Trunk Sewer are not of sufficient quality for the GWRS because of industrial and desalter contributors. Thus, although SARI flows are within P1 service area, they must be diverted to P2. This is currently being done by gravity at P1 s headworks. To meet the requirements for the GWRS, the Ellis Avenue Pump Station is required to divert the flows destined for P2 to P1. These flows will be combined with the P1 flows for treatment before being delivered to the GWRS. During a typical day s operation, flows in excess of 104-mgd will be treated and discharged through the ocean ES-3

7 outfall and flows below 104-mgd will be supplemented by the Ellis Avenue Pump Station to maintain flow to the GWRS at a relatively constant rate. EXISTING ELLIS AVENUE PUMP STATION There is an existing pump station located under the intersection of Ellis Avenue and Bushard Street that is capable of diverting flows from the P2 service area to P1. However, the capacity of the station is limited to 10-mgd, which is not sufficient to match flows to plant capacities or for GWRS. The existing station was last upgraded in late 1970 s. Due to limitations at the site and limitations with the existing structures, it is not possible to expand the existing facility to meet the required capacity needs. Furthermore, the station does not comply with current code requirements and presents safety risks to District Staff who are required to perform routine operation and maintenance tasks at the facility. Safety risks include the following: Below grade electrical equipment subject to flooding. The existing dry well is classified as Class 1, Division 2 environment in accordance with the National Electric Code, the National Fire Protection Association (NFPA), 820 and the District Design Guidelines. The existing electrical equipment located in the dry well area is not suitable for this classification. Access to pumps, electrical equipment and appurtenances is from Ellis Avenue and Bushard Street. Traffic control is required to pull this equipment from the dry well for maintenance and repairs. Maintenance personnel are required to work in the street placing them at risk from traffic. A Bilco type hatch located in the sidewalk provides access to the dry well. The Bilco hatch does not meet the requirements of the Uniform Building Code for means of egress. As a result, the dry well is classified as a confined space. The dry well area contains pumps, valves, electrical equipment and controls that must be accessed on a routine basis. District staff are required to enter this confined space to perform routine operation tasks placing them at risk of personnel injury. PUMP STATION DESIGN CAPACITY The Ellis Avenue Pump Station will be used to convey flows from the collection system destined for Plant No. 2 (Knott, Magnolia and Miller Holder Trunk Sewers) to the Plant No. 1 Headworks. The pump station design capacity will be sufficient to meet the following needs: Limit the flow rate at Plant No. 2 to the rated design average capacity (approximately 144-mgd) through the year ES-4

8 Maintain a minimum base flow rate at Plant No. 1 (approximately 104-mgd) as required for the Ground Water Replenishment System (GWRS). The design capacity is defined as the maximum pumping rate of all duty pumps with one standby pump in reserve. To meet the above referenced needs, the Ellis Avenue Pump Station is required to have a design capacity of approximately 50-mgd as defined in the 2002 Interim Strategic Plan Update. With the standby pump in service, the station could convey a maximum flow rate of approximately 60-mgd. IDENTIFICATION OF PUMP STATION ALTERNATIVES Pump station alternatives were identified based on meetings and discussions held with the District staff, field visits to the proposed sites, input from the August 25, 2003 public meeting regarding the initial Notice of Preparation (NOP), and preliminary investigations of existing utilities along the proposed force main and gravity sewer alignments. In identifying pump station alternatives, the following criteria were considered important to the selection process: Effective Corridor Access for Construction, Operations and Maintenance. Size of Site. Existing Obstructions. follows: Pump station alternatives that met the above referenced criteria are summarized as Alternative A Alternative B Alternative C Alternative D Alternative E Alternative F Alternative G Alternative H Alternative I Alternative J Alternative K OCSD Plant No. 1 North Corner Commercial Park Ellis and Pacific OCSD Plant No. 1 South Moiola Elementary School Finch Street Callens Ranch on Ellis Fountain Valley High School (North/South Configurations) Pacific Decorating Talbert/Bushard Methodist Church Bushard Ellis and Bushard Two Homes Ellis and Bushard Below-ground Walgreens Garfield/Bushard ES-5

9 To aid with references throughout the text of this report, alternatives were identified with the letters A through K. In general, alternatives were identified from east to west and north to south. EVALUATION OF PUMP STATION ALTERNATIVES Based on the pump station alternatives that were identified, several key evaluation features were developed that were considered essential to the engineering and technical viability of an alternative. These features are ultimately used to compare each alternative and to identify the most technically feasible alternatives, moderately technically feasible alternatives, and least technically feasible alternatives. Key evaluation features are summarized as follows: Pipe Length. Operations and Maintenance o Facility Operations and Maintenance o Pump Operations and Maintenance. Utility Requirements. Efficient Design o Specific Design Issues o Construction Site Access and Traffic Planning o Agency and Utility Company Requirements. Constructability o Specific Constructability Issues o Major Construction Tie-ins o Contaminated Soil and Groundwater o Geotechnical Assessment. Future District Operational Flexibility. Sections 3 through 13 of this memorandum present a detailed discussion of each pump station alternative with respect to the key evaluation features. For each feature and each alternative, a brief discussion was presented and advantages and disadvantages were identified ES-6

10 LIFE CYCLE COST EVALUATION Probable construction costs and life cycle costs were prepared for each of the pump station alternatives. The costs are presented below in Table ES-1. Construction costs were based on February 2003 dollars and include an allowance for overhead, profit and estimating contingency at 50 percent. Life cycle costs were based on a period of 50 years and include operation and maintenance costs such as labor, power and maintenance materials. Life cycle costs also include equipment replacement costs and the anticipated salvage value of the facilities at the end of the period ES-7

11 Item Alternative A OCSD Plant No. 1 North Corner Alternative B Commercial Park Ellis & Pacific Table ES-1 Orange County Sanitation District Job No. I-10 Replacement of the Ellis Avenue Pump Station Alternative C OCSD Plant No. 1 south Life Cycle Cost Analysis Alternative D Moiola Elementary School Finch St Alternative E Callens Ranch on Ellis Alternative F Fountain Valley High School Alternative G Pacific Decorating Talbert / Bushard Alternative H Methodist Church Bushard Alternative I Ellis & Bushard Two Homes Alternative J Ellis & Bushard Belowground Alternative K Walgreens Garfield / Bushard Ellis Avenue Pump Station $11,360,000 $14,400,000 $13,160,000 $12,200,000 $12,245,000 $12,453,000 $12,515,000 $12,734,000 $12,291,000 $12,311,000 $12,304,000 Mechanically Cleaned Bar Screen $3,090,000 $3,010,000 $0 $0 $0 $0 $0 $0 $0 $0 $0 Job No. I-10 Diversion Structure $626,000 $626,000 $815,000 $626,000 $626,000 $1,120,000 $1,037,000 $1,037,000 $641,000 $661,000 $815, inch Diameter Gravity Sewer $5,960,000 $5,868,000 $8,150,000 $1,140,000 $274,000 $2,044,000 $55,000 $350,000 $44,000 $94,000 $43, inch Diameter Force Main $250,000 $440,000 $3,380,000 $4,275,000 $3,854,000 $7,273,000 $6,266,000 $5,890,000 $4,653,000 $4,587,000 $6,084, inch Plant No. 1 Diversion Trunk $8,616,000 $8,616,000 $8,616,000 $8,616,000 $8,616,000 $8,616,000 $8,616,000 $8,616,000 $8,616,000 $8,616,000 $8,616,000 Heil Avenue Diversion Structure and 36-inch $1,729,000 $1,729,000 $1,729,000 $1,729,000 $1,729,000 $1,729,000 $1,729,000 $1,729,000 $1,729,000 $1,729,000 $1,729,000 Diameter Gravity Sewer Total Probable Construction Cost $31,631,000 $34,689,000 $35,850,000 $28,586,000 $27,344,000 $33,235,000 $30,218,000 $30,356,000 $27,974,000 $27,998,000 $29,591,000 Project 30% $9,489,000 $10,406,000 $10,755,000 $8,575,000 $8,203,000 $9,970,000 $9,065,000 $9,106,000 $8,392,000 $8,399,000 $8,877,000 Total Project Costs $41,120,000 $45,095,000 $46,605,000 $37,161,000 $35,547,000 $43,205,000 $39,283,000 $39,462,000 $36,366,000 $36,397,000 $38,468,000 Present Worth of Replacement Items $5,390,000 $5,340,000 $4,460,000 $4,030,000 $4,030,000 $4,160,000 $4,280,000 $4,290,000 $4,100,000 $4,280,000 $4,130,000 Present Worth of Annual Expenditures $7,210,000 $7,220,000 $5,730,000 $5,020,000 $4,900,000 $5,440,000 $5,160,000 $5,160,000 $4,950,000 $5,070,000 $5,130,000 Present Worth of Salvage Value ($1,390,000) ($1,370,000) ($1,400,000) ($1,230,000) ($1,230,000) ($1,300,000) ($1,340,000) ($1,340,000) ($1,270,000) ($1,330,000) ($1,280,000) Total Life Cycle Cost $52,330,000 $56,285,000 $55,395,000 $44,981,000 $43,247,000 $51,505,000 $47,283,000 $47,572,000 $44,146,000 $44,417,000 $46,448, ES-8

12 SUMMARY OF PUMP STATION ALTERNATIVES TECHNICAL VIABILITY Based on the evaluation of each pump station alternative with respect to the key evaluation features and the life cycle cost analysis, the technical viability of each alternative was identified as follows: Most Technically Feasible: Alternatives found to be preferred, acceptable, or normal for a pump station of the size and character. Moderately Technically Feasible: Alternatives with some features that were considered to be atypical and undesirable and some features that were considered to be preferred or normal for a pump station of this size and character. Least Technically Feasible: Alternatives with numerous features considered to be atypical, undesirable or would require significant engineering and technical measures to implement Infeasible: Alternative C OCSD Plant No. 1 South was previously identified as infeasible. The following is a summary of each alternative with respect to the major groups. In addition, Table ES-2 provides a comparative summary of each pump station alternative s technical viability. MOST TECHNICALLY FEASIBLE ALTERNATIVES Based on the detail engineering and technical comparison, the following alternatives were determined to be most technically feasible from an engineering and technical viewpoint: Alternative G Pacific Decorating Talbert/Bushard Alternative H Methodist Church Bushard Alternative I Ellis and Bushard Two Homes These three alternatives were found to be most technically feasible for the following reasons: Pipe Length: Alternatives are located closest to the source of flow (Knott and Magnolia Trunk Sewers) ES-9

13 Operations and Maintenance: Alternatives provide the most reliable pump selection. Pumps identified for these alternatives provide stable pump operations over the entire flow and wet well operating range anticipated. Alternatives allow the use of a screw centrifugal pump impellers, which results in pumps being less susceptible to clogging and eliminates the need for upstream bar racks or bar screens. Since the alternatives are located closest to the source of flow, the alternatives do not have any lag time in the delivery of flow to the pump station. Alternatives with lag time are more difficult to design and to operate due to increased complexity in the pump control strategies. Without a significant lag time in the delivery of flow to the wet well, the alternatives result in the most reliable pump operation. Alternatives have the simplest pump control strategies, best pump selection, and do not require additional upstream equipment such as bar racks or bar screens. Utility Requirements: Due to the wet well depth and the length of force main, the alternatives result in relatively moderate energy consumption. Efficient Design: Alternatives result in the least complex planning and design effort and do not require significant engineering and technical measures to implement. Constructability: Alternatives require routine construction techniques to implement. Alternatives that require special techniques to implement increase construction risk, the potential for change orders, and the potential for construction delays. Maintains planned secondary treatment facility expansion contractors laydown space and space reserved for other on site construction projects. Future District Operational Flexibility: Alternatives provide flexibility to divert SARI flows from Plant No. 1 to Plant No. 2 through the existing 96-inch Knott and 108-inch Bushard Trunk Sewers. This flexibility may delay the need for a second interplant line in Brookhurst Avenue and could allow servicing of each trunk without bypass pumping. Project and Life Cycle Costs: The most technically feasible alternatives have low capital and life cycle costs ES-10

14 MODERATELY TECHNICALLY FEASIBLE ALTERNATIVES Based on the detail engineering and technical comparison, the following four alternatives were determined to be moderately technically feasible from an engineering and technical viewpoint: Alternative D - Moiola Elementary School Finch Street Alternative E Callens Ranch on Ellis Alternative J - Ellis and Bushard Below-ground Alternative K Walgreens Garfield/Bushard These alternatives provided similar advantages as the most technically feasible alternatives including the following: Alternative D Moiola Elementary School Finch Street: Operations and Maintenance: Alternative provides the most reliable pump selection. Pumps identified for this alternative provide stable pump operations over the entire flow and wet well operating range anticipated. Alternative allows the use of a screw centrifugal pump impeller, which results in pumps being less susceptible to clogging and eliminates the need for upstream bar screens or bar racks. Utility Requirements: Due to the wet well depth and the length of force main, this alternative results in relatively moderate energy consumption. Constructability: Maintains planned secondary treatment facility expansion contractors laydown space and space reserved for other on site construction projects at Plant No. 1. With permission of the Fountain Valley School District, space for the construction lay down areas, soil stockpile, contractor s field offices, and contractor s employee parking could be provided on site. Project and Life Cycle Costs: Alternative has low capital and life cycle costs. Alternative E Callens Ranch on Ellis Pipe Length: Alternative requires minimal lengths of new gravity sewer piping minimizing surface and traffic disruptions during construction ES-11

15 Operations and Maintenance: Alternative provides the most reliable pump selection. Pumps identified for this alternative provide stable pump operations over the entire flow and wet well operating range anticipated. Alternative allows the use of a screw centrifugal pump impeller, which results in pumps being less susceptible to clogging and eliminates the need for upstream bar screens or bar racks. Utility Requirements: Due to the wet well depth and the length of force main, this alternative results in relatively moderate energy consumption. Efficient Design: Alternative results in least complex planning and design effort and does not require significant engineering and technical measures to implement. Constructability: Alternative requires routine construction techniques to implement. Alternatives that require special techniques to implement increase construction risk, the potential for change orders, and the potential for construction delays. Maintains planned secondary treatment facility expansion contractors laydown space and space reserved for other on site construction projects at Plant No. 1. Project and Life Cycle Costs: Alternative has the lowest capital and life cycle costs. Alternative J Ellis and Bushard Below-ground Pipe Length: Alternative is located closest to the source of flow (Knott and Magnolia Trunk Sewers). Operations and Maintenance: Alternative provides the most reliable pump selection. Pumps identified for this alternative provide stable pump operations over the entire flow and wet well operating range anticipated. Alternative allows the use of a screw centrifugal pump impellers, which results in pumps being less susceptible to clogging and eliminates the need for upstream bar screens or bar racks. Since the alternative is located closest to the source of flow, the alternative does not have any lag time in the delivery of flow to the pump station. Alternatives with lag time are more difficult to design and to operate due to increased complexity in the pump control strategies ES-12

16 Without a significant lag time in the delivery of flow to the wet well, the alternative results in the most reliable pump operation. Alternative has the simplest pump control strategies, best pump selection, and does not require additional upstream equipment such as bar racks or bar screens. Utility Requirements: Due to the wet well depth and the length of force main, the alternative results in relatively moderate energy consumption. Constructability: Maintains planned secondary treatment facility expansion contractors laydown space and space reserved for other on site construction projects at Plant No. 1. Future District Operational Flexibility: Alternative provides flexibility to divert SARI flows from Plant No. 1 to Plant No. 2 through the existing 96-inch Knott and 108-inch Bushard Trunk Sewers. This flexibility may delay the need for a second interplant line in Brookhurst Avenue and could allow servicing of each trunk without bypass pumping. Project and Life Cycle Costs: Alternative has low capital and life cycle costs. Alternative K Walgreens Garfield/Bushard Pipe Length: Alternative is located closest to the source of flow (Knott and Magnolia Trunk Sewers). Operations and Maintenance: Alternative provides the most reliable pump selection. Pumps identified for this alternative provides stable pump operations over the entire flow and wet well operating range anticipated. Alternative allows the use of a screw centrifugal pump impellers, which results in pumps being less susceptible to clogging and eliminates the need for upstream bar screens or bar racks. Since the alternative is located closest to the source of flow, the alternative does not have any lag time in the delivery of flow to the pump station. Alternatives with lag time are more difficult to design and to operate due to increased complexity in the pump control strategies. Without a significant lag time in the delivery of flow to the wet well, the alternative results in the most reliable pump operation. Alternative has the simplest pump control strategies, best pump selection, and does not require additional upstream equipment such as bar racks or bar screens ES-13

17 Utility Requirements: Due to the wet well depth and the length of force main, the alternative results in relatively moderate energy consumption. Construtability: Alternative requires routine construction techniques to implement. Alternatives that require special techniques to implement increase construction risk, the potential for change orders, and the potential for construction delays. Maintains planned secondary treatment facility expansion contractors laydown space and space reserved for other on site construction projects at Plant No. 1. Project and Life Cycle Costs: Alternative has low capital and life cycle costs. However, these alternatives had several disadvantages that made them moderately technically feasible. These disadvantages are as follows: Alternative D Moiola Elementary School Finch Street Pipe Length: Alternative requires approximately 1,300 linear ft of 60 inch diameter gravity sewer from the Knott Trunk on Ellis Avenue to the proposed pump station site. This segment of sewer will result in additional surface disruption and traffic disruption during construction. Alternative requires approximately 7,700 linear ft of 48 inch diameter force main from the pump station on Finch Street to the Plant No. 1 site. This segment of force main will result in additional surface disruption and traffic disruption during construction. Operations and Maintenance: Alternative requires a lag time of approximately 30 minutes to convey flow from the Magnolia and Knott Trunks to the pump station wet well. The lag time increases the complexity of the pump control strategies and may result in a condition where flow is not available to the pumps when a demand exists at Plant No. 1. Due to the lag time in the delivery of flow to the wet well, the alternative requires a complex pump control strategy to ensure that the pumps operate continuously. Without the control strategy, the pumps could cycle on and off resulting in flow surges at Plant No. 1. In addition, the self cleaning wet well configuration is designed for continuous pump operation; pump cycling could result in an excessive number of pump starts per hour and could lead to excess wear on the motor and possible premature motor failure ES-14

18 Efficient Design: Alternative requires a 60-inch diameter gravity sewer, 48-inch diameter force main and an electrical ductbank to convey flow and power to and from the pump station. A portion of these utilities would run parallel to Finch Street. Finch Street serves as the primary access to Moiola Elementary School. Additional planning and engineering would be required to maintain access to the school during construction of these utilities. Alternative would require coordination and approval from the school board. This would add an additional level of complexity to the planning and design effort. Constructability: Alternative requires special construction techniques to implement. The required l,300 linear feet of gravity sewer, force main and electrical ductbank through the Callens Ranch property and along Finch Street may result in disruptions to the normal school traffic patterns. Future District Operational Flexibility: Alternative does not provide flexibility to divert SARI flows from Plant No. 1 to Plant No. 2 through the existing 96-inch Knott and 108-inch Bushard Trunk Sewers. Alternative E Callens Ranch on Ellis Operations and Maintenance: Alternative requires a lag time of approximately 20 minutes to convey flow from the Magnolia and Knott Trunks to the pump station wet well. The lag time increases the complexity of the pump control strategies and may result in a condition where flow is not available to the pumps when a demand exists at Plant No. 1. Due to the lag time in the delivery of flow to the wet well, the alternative requires a complex pump control strategy to ensure that the pumps operate continuously. Without the control strategy, the pumps could cycle on and off resulting in flow surges at Plant No. 1. In addition, the self cleaning wet well configuration is designed for continuous pump operation; pump cycling could result in an excessive number of pump starts per hour and could lead to excess wear on the motor and possible premature motor failure. Future District Operational Flexibility: This alternative does not provide flexibility to divert SARI flows from Plant No. 1 to Plant No. 2 through the existing 96-inch Knott and 108-inch Bushard Trunk Sewers ES-15

19 Alternative J Ellis and Bushard Below-ground Efficient Design: Alternative will require a below-ground electrical, instrumentation and control area. Placing this equipment below-ground increases the planning and design complexity of the pump station as follows: o The electrical instrumentation and control area will be accessed by District staff on a routine basis. As a result, this area must be designed with adequate means of egress and ventilation to avoid a confined space entry classification, if possible. o Below-grade electrical and control equipment could be subject to flooding. The station must be configured to avoid potential flooding of this critical equipment. Alternative will be located in Ellis Avenue adjacent to several existing homes. A portion of Ellis Avenue could be closed and access to the existing homes could be restricted during construction of the below-grade structures. Additional planning and design would be required to reroute traffic and to provide temporary sidewalks and drives to the existing homes. Several existing utilities in Ellis Avenue will require relocation to accommodate construction of the below-ground structures. Relocation of these utilities will require additional coordination and approvals from the utility companies. Constructability: Alternative requires special construction techniques to implement. Construction of this alternative would result in a major disruption of the Ellis/Bushard intersection for approximately 18 months. In addition, several existing utility pipelines, conduits, etc. would need to be relocated. The relocations would cause periodic disruption in services to the local area that these utilities service. The existing groundwater injection well located at the northwest corner of Ellis Avenue and Bushard Street must be maintained at all times during construction. As a result, special construction techniques may be required to ensure that the well is not disturbed. In addition, temporary piping may be required to ensure the continuous flow of water to the injection well. Alternative K Walgreens Garfield/Bushard Efficient Design: Alternative requires the 48-inch diameter force main to pass under the existing Fountain Valley Channel located on Garfield Avenue between Bushard and Brookhurst Streets. The foundation for this channel under Garfield Avenue is supported by piles. Planning and design for the force main will require additional effort to ensure that the force main can be constructed between the existing foundation support piles ES-16

20 Constructability: For the force main crossing of the existing Fountain Valley Channel on Garfield Avenue, the force main would need to pass between the existing piles spaced at 12 feet on centers. The piles add complexity to the force main installation. This complexity increases the construction risks the potential for change orders and construction delays. Future District Operational Flexibility: Alternative does not provide flexibility to divert SARI flows from Plant No. 1 to Plant No. 2 through the existing 96-inch Knott and 108-inch Bushard Trunk Sewers. LEAST TECHNICALLY FEASIBLE ALTERNATIVES Based on the detail engineering and technical comparison, the following alternatives were determined to be least technically feasible from an engineering and technical viewpoint: Alternative A OCSD Plant No. 1 North Corner Alternative B Commercial Park Ellis and Pacific Alternative F N Fountain Valley High School North Configuration Alternative F S Fountain Valley High School South Configuration These alternatives provided similar advantages as the most promising sites including the following: Alternative A OCSD Plant No. 1 North Corner Pipe Length: Alternative requires approximately 250 linear ft of 48-inch diameter force main. This line is located at Plant No. 1 on District owned property. This segment of force main will result in minimal surface disruption and traffic control issues during construction. Utility Requirements: Due to the wet well depth and the length of force main, this alternative results in relatively lower energy consumption. Alternative B Commercial Park Ellis and Pacific Pipe Length: Alternative requires approximately 800 linear ft of 48-inch diameter force main. This segment of force main will result in minimal surface disruption and traffic control issues during construction ES-17

21 Utility Requirements: Due to the wet well depth and the length of force main, this alternative results in relatively lower energy consumption. Constructability: Maintains planned secondary treatment facility expansion contractors laydown space and space reserved for other on site construction projects at Plant No. 1. Alternative F Fountain Valley High School (North and South Configurations) Operations and Maintenance: Alternative provides the most reliable pump selection. Pumps identified for this alternative provides stable pump operations over the entire flow and wet well operating range anticipated. Alternative allows the use of a screw centrifugal pump impellers, which results in pumps being less susceptible to clogging and eliminates the need for upstream bar screens or bar racks. Construtability: Maintains planned secondary treatment facility expansion contractors laydown space and space reserved for other on site construction projects at Plant No. 1. Future District Operational Flexibility: Alternative provides flexibility to divert SARI flows from Plant No. 1 to Plant No. 2 through the existing 96-inch Knott and 108-inch Bushard Trunk Sewers. This flexibility may delay the need for a second interplant line in Brookhurst Avenue and could allow servicing of each trunk without bypass pumping. However, these alternatives have several disadvantages that make them least technically feasible. These disadvantages are as follows: Alternative A OCSD Plant No. 1 North Corner Pipe Length: Alternative requires approximately 5,200 linear ft of 60 inch diameter gravity sewer from the Knott Trunk on Ellis Avenue to the proposed pump station site. This segment of sewer will result in additional surface disruption and traffic disruption during construction. Operations and Maintenance: Alternative requires the use of a three-vane impeller pump selection. This pump selection could be susceptible to persistent ragging problems. As a ES-18

22 result, a mechanically cleaned screen would be required upstream of the wet well to mitigate ragging problems. Mechanically cleaned screens would increase required maintenance, increase operations and maintenance traffic to the site, increase the potential for odors from screenings handling and disposal, require additional space, and increased project and life cycle costs. Alternative requires a lag time of approximately 60 minutes to convey flow from the Magnolia and Knott Trunks to the pump station wet well. The lag time increases the complexity of the pump control strategies and may result in a condition where flow is not available to the pumps when a demand exists at Plant No. 1. Due to the lag time in the delivery of flow to the wet well, the alternative requires a complex pump control strategy to ensure that the pumps operate continuously. Without the control strategy, the pumps could cycle on and off resulting in flow surges at Plant No. 1. In addition, the self cleaning wet well configuration is designed for continuous pump operation; pump cycling could result in an excessive number of pump starts per hour and could lead to excess wear on the motor and possible premature motor failure. Efficient Design: Alternative results in substructure approximately 45 feet deep. The depth of this structure increases the complexity of the structural design and the construction and dewatering methods. Alternative requires 5,200 linear ft of 60-inch diameter gravity sewer to convey flow to the pump station. This sewer would be approximately 35 feet deep as it approaches the pump station and would be routed under the existing and proposed Plant No. 1 Diversion Trunk. Due to the depth of this sewer, tunnel construction methods would be required increasing the planning and design effort. The proposed site is located adjacent to the main plant entrance roadway. Construction of the pump station at this location could result in short periods of time where the access roadway is blocked for construction purposes. Access to the plant must be maintained at all times to accommodate emergency vehicles (fire, police and emergency response teams). As a result, temporary roadways or access drives may be required to ensure access to these vehicles. Constructability: Alternative requires special construction techniques to implement. The depth of this structure (approximately 45 feet deep) increases the complexity of construction activities including installation of foundation support systems, shored excavation systems and dewatering. In addition, the depth complicates the logistics of moving men and material into and out of the excavation to complete the work. These complexities increase the construction risk and the potential for change orders and construction delays. Requires construction of approximately 5,200 linear feet of gravity sewer along Ellis Avenue. Tunneling would be required to construct this sewer due ES-19

23 to the depth (approximately 35 feet below grade). Tunnel construction methods increase construction risk, the potential for change orders and construction delays. Removes planned secondary treatment facility expansion Contractor laydown space and space for other on site construction projects at Plant No. 1. This will complicate and delay Plant No. 1 construction activities and sequencing. The sequencing is currently optimized to achieve full secondary treatment as soon as possible. Future District Operational Flexibility: Alternative does not provide flexibility to divert SARI flows from Plant No. 1 to Plant No. 2 through the existing 96-inch Knott and 108-inch Bushard Trunk Sewers. Project and Life Cycle Costs: Alternative has high capital and life cycle costs. Alternative B Commercial Park Ellis and Pacific Pipe Length: Alternative requires approximately 5,200 linear ft of 60 inch diameter gravity sewer from the Knott Trunk on Ellis Avenue to the proposed pump station site. This segment of sewer will result in additional surface disruption and traffic disruption during construction. Operations and Maintenance: Alternative requires the use of a three-vane impeller pump selection. This pump selection could be susceptible to persistent ragging problems. As a result, a mechanically cleaned screen would be required upstream of the wet well to mitigate ragging problems. Mechanically cleaned screens would increase required maintenance, increase operations and maintenance traffic to the site, increase the potential for odors from screenings handling and disposal, require additional space, and increased project and life cycle costs. Alternative requires a lag time of approximately 60 minutes to convey flow from the Magnolia and Knott Trunks to the pump station wet well. The lag time increases the complexity of the pump control strategies and may result in a condition where flow is not available to the pumps when a demand exists at Plant No. 1. Due to the lag time in the delivery of flow to the wet well, the alternative requires a complex pump control strategy to ensure that the pumps operate continuously. Without the control strategy, the pumps could cycle on and off resulting in flow surges at Plant No. 1. In addition, the self cleaning wet well configuration is designed for continuous pump operation; pump cycling could result in an excessive number of pump starts per hour and could lead to excess wear on the motor and possible premature motor failure ES-20

24 Efficient Design: Alternative results in substructure approximately 40 feet deep. The depth of this structure increases the complexity of the structural design and the construction and dewatering methods. Alternative requires 5,200 linear ft of 60-inch diameter gravity sewer to convey flow to the pump station. This sewer would be approximately 30 feet deep as it approaches the pump station and would be routed under the existing and proposed Plant No. 1 Diversion Trunk. Due to the depth of this sewer, tunnel construction methods would be required increasing the planning and design effort. Constructability: Alternative requires special construction techniques to implement. The depth of this structure (approximately 40 feet) increases the complexity of construction activities including installation of foundation support systems, shored excavation systems and dewatering. In addition, the depth complicates the logistics of moving men and material into and out of the excavation to complete the work. These complexities increase the construction risk and the potential for change orders and construction delays. Requires construction of approximately 5,200 linear feet of gravity sewer along Ellis Avenue. Tunneling would be required to construct this sewer due to the depth (approximately 30 feet below grade). Tunnel construction methods increase construction risk, the potential for change orders, and construction delays. Future District Operational Flexibility: Alternative does not provide flexibility to divert SARI flows from Plant No. 1 to Plant No. 2 through the existing 96-inch Knott and 108-inch Bushard Trunk Sewers. Project and Life Cycle Costs: Alternative has high capital and life cycle costs. Alternative F Fountain Valley High School (North and South Configurations) Pipe Length: Alternative requires approximately 1,800 to 2,500 linear ft of 60 inch diameter gravity sewer from the Knott Trunk on Ellis Avenue to the proposed pump station site. This segment of sewer will result in additional surface disruption and traffic disruption during construction. Alternative resulted in the longest force main, approximately 11,400 to 13,000 lf. The longer force main requires more air and vacuum valves and results in additional surface and traffic disruptions during construction ES-21

25 Operations and Maintenance: Alternative requires a lag time of approximately 15 minutes to convey flow from the Magnolia and Knott Trunks to the pump station wet well. The lag time increases the complexity of the pump control strategies and may result in a condition where flow is not available to the pumps when a demand exists at Plant No. 1. Due to the lag time in the delivery of flow to the wet well, the alternative requires a complex pump control strategy to ensure that the pumps operate continuously. Without the control strategy, the pumps could cycle on and off resulting in flow surges at Plant No. 1. In addition, the self cleaning wet well configuration is designed for continuous pump operation; pump cycling could result in an excessive number of pump starts per hour and could lead to excess wear on the motor and possible premature motor failure. Utility Requirements: Due to the wet well depth and the length of force main, the alternative results in the highest energy consumption. Efficient Design: Bushard Street between Talbert Avenue and Slater Avenue is crowded with numerous existing utilities. Construction of a new force main and gravity sewer along this alignment may require relocation of existing utilities or require special construction techniques such as tunneling to implement. Alternative would require coordination and approval from the Huntington Beach Union High School District. This would add an additional level of complexity to the planning and design effort. Constructability: Alternative requires special construction techniques to implement. The required 1,800 to 2,500 linear feet of 60-inch diameter gravity sewer along Bushard Street may require tunnel construction methods due to the proximity to existing power poles and utilities. Tunnel construction methods increase construction risk, the potential for change orders, and construction delays. Special construction techniques may also be required to maintain access to the High School at all times during construction. The proposed site has an open LUST case at the intersection of El Camino and Bushard Street. As a result, the probability of encountering contaminated soils and groundwater at this site is higher than other alternatives. Contaminated soils and groundwater would require special handling procedures to remove and dispose of these materials. If encountered, this could result n change orders during construction and potential construction delays. The existing site is underlain with peat deposits. Peat deposits could increase the complexity of the substructure construction primarily the shored excavation system. This complexity increases construction risk at this site and the potential for change orders and construction delays ES-22

26 Project and Life Cycle Costs: Alternative has high capital and life cycle costs ES-23

27 ES-24 Table ES-2 Orange County Sanitation District Job No. I-10 Replacement of the Ellis Avenue Pump Station Comparative Summary of Pump Station Alternatives' Technical Viability MOST TECHNICALLY FEASIBLE MODERATELY TECHNICALLY FEASIBLE LEAST TECHNICALLY FEASIBLE INFEASIBLE G H I D E J K A B F N F S C Pacific Decorating Methodist Church Ellis & Bushard Moila Elem. School Callens Ranch Ellis & Bushard Walgreens OCSD Plant No. 1 Commercial Park F. V High School F. V High School OCSD Plant No. 1 KEY TECHNICAL DIFFERENTIATORS Talbert/Bushard Bushard Two Homes Finch St. on Ellis Below-ground Garfield/Bushard North Corner Ellis & Pacific North Config. South Config. South PIPE LENGTH Piping Length - A measure of the amount of inlet & outlet piping in feet. Distances are approximate. Values shown as Gravity Main / Force Main. Greater distance equates to greater amount of surface and traffic disruption during construction. 65 / 10, / 9, / 7,900 1,300 / 7, / 6, / 8, / 10,500 5,200 / 250 5,200 / 800 2,500 / 13, / OPERATIONS AND MAINTENANCE Pump Operations and Maintenance Pump Reliability - A measure of the ability to select pumps that will present fewest operational difficulties and less required maintenance man-hours. The ability to operate stably on the pump curve, which limits Mean Time Between Failures and lengthens capital life of pumps and associated control equipment. This factor does not include measures of pump efficiency. Pump Operations - A measure of how problem free a station is predicted to be based on design difficulty. Station location will affect control strategies and equipment selections. These in turn directly affect operations and the number of "work arounds" District Staff may have to put in place. Ranked 1-4 with 1 being most reliable and 4 being least reliable. Pump Clogging - The measure of the ability to select pumps that are less susceptible to clogging by large debris. Location determines hydraulic conditions. Hydraulic conditions dictate type of pump that must be selected. Not all pump types are available for all hydraulic conditions. Not all pump types offer the same abilities with regards to clog susceptibility. Lag Time - The measure of time between flow change request & response at flow source. More lag time = more difficult design and operations and higher chance of failure. UTILITY REQUIREMENTS Energy Consumed - The measure of energy consumed based on projected total station pump horsepower and force main length. Ranked Lower, Moderate, and Higher. Lower = Relatively less energy consumption. Moderate = Relatively moderate / average energy consumption. Higher = Relatively higher energy consumption. EFFICIENT DESIGN Efficient Design - The measure of the ability to design a pump station that will not require extraordinary construction site management to complete the work or extraordinary permit requirements. Ranked 1-4 with 1 being least complex and 4 being most complex. CONSTRUCTABILITY Constructability - The measure of the ability to construct project. Assesses whether routine construction techniques, some special construction techniques, or extraordinary construction techniques are required to construct project. The less routine techniques are, the more expensive construction is. In addition, the potential for construction impacts is greater. FUTURE DISTRICT OPERATIONAL FLEXIBILITY Future District Operational Flexibility - Measures the ability of District to use Knott Trunk between Brookhurst & Bushard in future. Ability to use would then allow SARI flow diversions to the Bushard Trunk. This would be an operational advantage in peak wet weather flow events, and would also allow the District to take the Interplant Pipeline (96" pipe from Brookhurst to Plant 2) out of service for maintenance and repairs. The District does not currently have this flexibility. Yes = provides future flexibility. No = Does not provide future flexibility. PROJECT AND LIFE CYCLE COSTS Estimated Project Cost - The estimated project capital cost of each alternative is provided on the top row. The estimated life cycle cost is provided on the bottom row. The estimates are per American Association of Cost Engineers standards. As such the estimates at this stage of the project are considered to be within +50% and -30%. Most Reliable Most Reliable Most Reliable Most Reliable Most Reliable Most Reliable Most Reliable Least Reliable Least Reliable Most Reliable Most Reliable Less Susceptible Less Susceptible Less Susceptible Less Susceptible Less Susceptible Less Susceptible Less Susceptible More Susceptible More Susceptible Less Susceptible Less Susceptible 0 minutes 0 minutes 0 minutes 30 minutes 20 minutes 0 minutes 0 minutes 60 minutes 60 minutes 15 minutes 15 minutes Relatively Moderate Relatively Moderate Relatively Moderate Relatively Moderate Relatively Moderate Relatively Moderate Relatively Moderate Relatively Lower Relatively Lower Relatively Higher Routine Routine Routine Special Techniques Routine Special Techniques Routine Special Techniques Special Techniques Special Techniques Yes Yes Yes No No Yes No No No Yes Yes Relatively Higher Special Techniques $39.3 Million $39.5 Million $36.4 Million $37.2 Million $35.5 Million $36.4 Million $38.5 Million $41.1 Million $45.1 Million $43.2 Million $43.2 Million $47.3 Million $47.6 Million $44.1 Million $45.0 Million $43.2 Million $44.4 Million $46.4 Million $52.3 Million $56.3 Million $51.5 Million $51.5 Million Secondary treatment facilities have been planned for this site. Site is no longer available. Therefore, there is no room for a pump station at this location.