Volume i executive summary

1218 THIRD AVENUE, SUITE 1600 • SEATTLE, WASHINGTON 98101 • P. 206.684.6532 • F. 206.903.0419pw://Carollo/Documents/Client/WA/Oak Harbor/8549A00/Deliverables/Facilities Plan/Cover_TOC.docx

City of Oak Harbor

WASTEWATER FACILITIES PLAN

Executive Summary

DRAFT

March 2013

ASSOCIATED FIRMS

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This Wastewater Facilities Plan was developed in coordination with:

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City of Oak Harbor

Wastewater Facilities Plan

TABLE OF CONTENTS

Page No.

ES.1 INTRODUCTION ....................................................................................................... 1 ES.1.1 Project Need ............................................................................................ 1 ES.1.2 Project Goal ............................................................................................. 1

ES.2 PLANNING AREA CHARACTERISTICS .................................................................. 2 ES.2.1 Service Area ............................................................................................ 2

ES.3 EXISTING FACILITIES .............................................................................................. 2 ES.3.1 Existing Treatment Facilities .................................................................... 2 ES.3.2 Existing Effluent Outfalls .......................................................................... 4 ES.3.3 Existing Wastewater Collection System .................................................. 4

ES.4 WASTEWATER FLOWS AND LOADS ..................................................................... 5 ES.4.1 Flow and Load Projections ...................................................................... 5 ES.4.2 Phasing Scenarios For Growth ................................................................ 7

ES.5 REGULATORY REQUIREMENTS ............................................................................ 8 ES.5.1 Effluent Quality Goals .............................................................................. 8 ES.5.2 Biosolids Management .......................................................................... 10 ES.5.3 Other Environmental Documents ........................................................... 10

ES.6 ALTERNATIVES DEVELOPMENT AND EVALUATION ......................................... 11 ES.6.1 Project Objectives and Evaluation Criteria ............................................ 11 ES.6.2 Preliminary Alternatives ......................................................................... 11 ES.6.3 Initially Proposed Sites .......................................................................... 13 ES.6.4 Final Sites and Alternatives ................................................................... 18

ES.7 PROPOSED ALTERNATIVE ................................................................................... 22 ES.7.1 Wastewater Treatment Facility .............................................................. 22 ES.7.2 Wastewater Conveyance System .......................................................... 24 ES.7.3 Treated Effluent Outfall .......................................................................... 24 ES.7.4 Project Phasing Scenarios ..................................................................... 24 ES.7.5 Phase 1 Cost Summary ......................................................................... 26

ES.8 IMPLEMENTATION PLAN ...................................................................................... 28 ES.8.1 Financial Analysis Summary .................................................................. 28

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LIST OF TABLES Table ES.1 Population Projections ................................................................................... 5 Table ES.2 Current Flows and Loads............................................................................... 6 Table ES.3 Projected Flows and Loads ........................................................................... 7 Table ES.4 Effluent Quality Goals .................................................................................... 8 Table ES.5 Windjammer Vicinity MBR Key Considerations ........................................... 21 Table ES.6 Crescent Harbor North MBR Key Considerations ....................................... 21 Table ES.7 Crescent Harbor North AS Key Considerations ........................................... 22 Table ES.8 Phase 1 Capacity Summary ........................................................................ 26 Table ES.9 Total Phase 1 Cost Comparison (in millions) ............................................... 28 Table ES.10 City Share of Phase 1 Capital Costs (escalated, in millions) ....................... 30

LIST OF FIGURES Figure ES.1 Study Area, Topography, and Existing System ............................................. 3 Figure ES.2 Growth Scenarios for Phasing ....................................................................... 9 Figure ES.3 Project Objectives ........................................................................................ 12 Figure ES.4 Potential WWTP Sites ................................................................................. 14 Figure ES.5. TBL+ Analysis of Preliminary Alternatives ................................................... 15 Figure ES.6 Six Sites For Further Evaluation .................................................................. 16 Figure ES.7 TBL+ Analysis of Refined Alternatives ........................................................ 17 Figure ES.8 Windjammer Vicinity Charrette Results ....................................................... 19 Figure ES.9 Crescent Harbor North Charrette Results .................................................... 20 Figure ES.10 Treatment Process Flow Schematic ............................................................ 23 Figure ES.11 Conveyance Improvements for Scenario 1 .................................................. 25 Figure ES.12 Estimated Phase 1 Project Costs ................................................................ 27 Figure ES.13 Proposed Schedule ..................................................................................... 29 Figure ES.14 Monthly Sewer Rate Analysis ...................................................................... 31

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City of Oak Harbor

Wastewater Facilities Plan

TABLE OF CONTENTS

Page No.

ES.1 INTRODUCTION ....................................................................................................... 1 ES.1.1 Project Need ............................................................................................ 1 ES.1.2 Project Goal ............................................................................................. 1

ES.2 PLANNING AREA CHARACTERISTICS .................................................................. 2 ES.2.1 Service Area ............................................................................................ 2

ES.3 EXISTING FACILITIES .............................................................................................. 2 ES.3.1 Existing Treatment Facilities .................................................................... 2 ES.3.2 Existing Effluent Outfalls .......................................................................... 4 ES.3.3 Existing Wastewater Collection System .................................................. 4

ES.4 WASTEWATER FLOWS AND LOADS ..................................................................... 5 ES.4.1 Flow and Load Projections ...................................................................... 5 ES.4.2 Phasing Scenarios For Growth ................................................................ 7

ES.5 REGULATORY REQUIREMENTS ............................................................................ 8 ES.5.1 Effluent Quality Goals .............................................................................. 8 ES.5.2 Biosolids Management .......................................................................... 10 ES.5.3 Other Environmental Documents ........................................................... 10

ES.6 ALTERNATIVES DEVELOPMENT AND EVALUATION ......................................... 11 ES.6.1 Project Objectives and Evaluation Criteria ............................................ 11 ES.6.2 Preliminary Alternatives ......................................................................... 11 ES.6.3 Initially Proposed Sites .......................................................................... 13 ES.6.4 Final Sites and Alternatives ................................................................... 18

ES.7 PROPOSED ALTERNATIVE ................................................................................... 22 ES.7.1 Wastewater Treatment Facility .............................................................. 22 ES.7.2 Wastewater Conveyance System .......................................................... 24 ES.7.3 Treated Effluent Outfall .......................................................................... 24 ES.7.4 Project Phasing Scenarios ..................................................................... 24 ES.7.5 Phase 1 Cost Summary ......................................................................... 26

ES.8 IMPLEMENTATION PLAN ...................................................................................... 28 ES.8.1 Financial Analysis Summary .................................................................. 28

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LIST OF TABLES Table ES.1 Population Projections ................................................................................... 5 Table ES.2 Current Flows and Loads............................................................................... 6 Table ES.3 Projected Flows and Loads ........................................................................... 7 Table ES.4 Effluent Quality Goals .................................................................................... 8 Table ES.5 Windjammer Vicinity MBR Key Considerations ........................................... 21 Table ES.6 Crescent Harbor North MBR Key Considerations ....................................... 21 Table ES.7 Crescent Harbor North AS Key Considerations ........................................... 22 Table ES.8 Phase 1 Capacity Summary ........................................................................ 26 Table ES.9 Total Phase 1 Cost Comparison (in millions) ............................................... 28 Table ES.10 City Share of Phase 1 Capital Costs (escalated, in millions) ....................... 30

LIST OF FIGURES Figure ES.1 Study Area, Topography, and Existing System ............................................. 3 Figure ES.2 Growth Scenarios for Phasing ....................................................................... 9 Figure ES.3 Project Objectives ........................................................................................ 12 Figure ES.4 Potential WWTP Sites ................................................................................. 14 Figure ES.5. TBL+ Analysis of Preliminary Alternatives ................................................... 15 Figure ES.6 Six Sites For Further Evaluation .................................................................. 16 Figure ES.7 TBL+ Analysis of Refined Alternatives ........................................................ 17 Figure ES.8 Windjammer Vicinity Charrette Results ....................................................... 19 Figure ES.9 Crescent Harbor North Charrette Results .................................................... 20 Figure ES.10 Treatment Process Flow Schematic ............................................................ 23 Figure ES.11 Conveyance Improvements for Scenario 1 .................................................. 25 Figure ES.12 Estimated Phase 1 Project Costs ................................................................ 27 Figure ES.13 Proposed Schedule ..................................................................................... 29 Figure ES.14 Monthly Sewer Rate Analysis ...................................................................... 31

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Acronyms & Abbreviations

AA annual average

AACE Associate of the Advancement of Cost Engineering

AAF average annual flow

AC asbestos cement

ADA Americans with Disability Act

AS Activated Sludge

BAF Biologically Aerated Filter

BOD biochemical oxygen demand

BWF base wastewater flow

CBD Central Business District

CCI Construction Cost Index

CCP concrete cylinder pipe

CDBG Community Development Block Grant

CERB Community Economic Revitalization Board

CFR Code of Federal Regulations

City City of Oak Harbor

CMP corrugated metal pipe

DHAP Department of Archaeology & Historic Preservation

DI ductile iron

DIN dissolved inorganic nitrogen

DMR discharge monthly report

DNS determination of nonsignificance

DO dissolved oxygen

DOH Washington State Department of Health

DS determination of significance

DWF dry weather flow

Ecology Washing State Department of Ecology

EDC endocrine disrupting compuonds

EFH essential fish habitat

EID Environmental Information Document

EIS Environmental Impact Statement

ENR Engineering News-Record

EPA Environmental Protection Agency

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F/M ratio food-microorganism ratio

FDA Food and Drug Administration

GMA Growth Management Act

gpad gallons per are per day

gpcd gallons per capita per day

gpd gallons per day

gpd/sf gallons per day per square foot

gpm gallons per minute

GT gravity thickener

HDPE high –density polyethylene

hp horsepower

HPA Hydraulic Project Approval

HRT hydraulic retention time

IFAS integrated fixed film activated sludge

I/I Infiltration and inflow

JARPA Joint Aquatic Resources Permit Application

JPA Joint Planning area

Lagoon Plant Seaplane Base Lagoon WWTP

LOTT Lakehaven, Olympia, Tacoma, Tumwater area

MBR membrane bioreactor

MBBR moving bed bioreactor

MDNS mitigated determination of nonsignificance

mg/L milligrams per liter

mgd millions of gallons per day

MHHW mean higher high water

MHI median household income

MLE Modified Ludzack Ettinger

MLLW mean lower – low water

MLR mixed liquor return

MLSS mixed liquor suspended solids

MM maximum month

MMF maximum month flow

MR Marine Reach

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NAS Naval Air Station

NH3 ammonia

NHPA National Historic Preservation Act of 1966

NOAA National Oceanic and Atmospheric Administration

NPDES National Pollutions Discharge Elimination System

NRDC Natural Resources Defense Council

NTU nephelometric turbidity units

NWCAA Northwest Clean Air Agency

O&M Operation and Maintenance

OHMC Oak Harbor Municipal Code

OS Open Space

PBP Planned Business Park

PD peak day

PDF peak day flow

PF public facilities

pH chemical balance measurement

PHF peak hour flow

PIP Planned Industrial Park

Plan Facilities Plan

POTW publicly owned treatment works

pp pounds per day

ppcd pounds per capita per day

ppd pounds per day

PRE Planned Residential Estate

PVC polyvinyl chloride

PWTF Public Works Trust Fund

RBC Rotating biological contactor

RCP reinforced concrete pipe

ROW right-of-way

SDC system development charges

SERP State Environment Review Process

SLR solids loading rate

SOR surface overflow rate

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SRF State Revolving Fund

SRT solids retention time

STAG State and Tribal Assistance Grants

SVI sludge volume index

TBL+ Triple Bottom Line Plus Technical

TF Trickling Filter

TF/SC Trickling Filter/Solids Contact

TIN total inorganic nitrogen

TMDL total maximum daily load

TOrC trace organic chemical

TSS total suspended solids

UFC Uniform Fire Code

UGA Urban growth area

USEDA United States Economic Development Administration

USDA-RD United States Department of Agriculture-Rural Development

UV ultraviolet

UVT ultraviolet transmittance

VFD variable frequency drive

VFW Veterans of Foreign Wars

WAC Washington Administrative Code

WDFW table 6.8

WDNR Washington State Department of Natural Resources

WSEC Washington State Energy Code

WWTP Wastewater treatment plant

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Executive Summary


ES.1 INTRODUCTION

The City of Oak Harbor (City) must replace two aging wastewater treatment facilities with a new facility that meets modern standards for reliability and performance. This Wastewater Facilities Plan (Plan) describes the proposed alternative for wastewater collection, treatment, and effluent discharge (marine and/or reclamation), in accordance with Washington Administrative Code (WAC) 173-240. Completing the projects recommended in this Plan will allow the City to provide continued reliable wastewater service to the community of Oak Harbor while protecting and preserving the surrounding environment.

ES.1.1 Project Need

The City’s wastewater system serves approximately 24,000 people within the City and the Navy Seaplane Base. Wastewater is currently treated at two facilities: a rotating biological contactor (RBC) facility near Windjammer Park, and a lagoon facility on the Navy’s Seaplane Base. A project is needed to replace the City’s two existing treatment facilities with a modern facility capable of meeting the objectives listed below. Although the existing facilities are currently able to meet the requirements of the City’s National Pollution Discharge Elimination System (NPDES) Permit, they are not able to provide reliable long-term service for a number of reasons:

The existing RBC facility is nearing the end of its useful life.

Both the RBC and Lagoon Plants lack the technology to meet increasingly stringent water quality standards, and have inadequate capacity to keep pace with anticipated population growth.

Both effluent outfalls have seen major failures; the RBC Oak Harbor outfall no longer functions and the Crescent Harbor outfall is functional but damaged.

The area surrounding the Seaplane Base Lagoon Plant was reclaimed as a saltwater marsh in 2009. The lagoons are now surrounded by environmentally sensitive areas and are subject to frequent high water conditions, making expansion or modifications to the new lagoons infeasible.

ES.1.2 Project Goal

The goal of this project is to “obtain the highest level of water quality practical while recognizing the limitations of the rate payers of the City to fund the improvements.” Specific project objectives include:

1. Providing continued reliable wastewater treatment service;

2. Meeting high standards for water quality;


3. Allowing phased expansion to meet future demands; and

4. Delivering construction and operation of a new facility by 2017 in a cost-effective manner.

ES.2 PLANNING AREA CHARACTERISTICS

The City of Oak Harbor is located near the northern end of Whidbey Island in Island County, Washington. The United States Navy operates two bases on Whidbey Island: the Seaplane Base located in the eastern portion of the City, and Ault Field which lies to the north of the City. The City covers approximately 6,030 acres (9.4 square miles), of which 2,820 acres (4.4 square miles) is occupied by the Navy’s Seaplane Base. The City’s Urban Growth Area (UGA) includes all of the City of Oak Harbor, as well as unincorporated areas to the north, between the City and Ault Field, and to the south and west of the City. The UGA represents the vicinity that is likely to be needed to accommodate growth over the next 20 years.

ES.2.1 Service Area

Figure ES.1 shows the study and service areas for this Plan, which includes all of the UGA, encompassing 7,540 acres (11.8 square miles) of land. A Joint Planning Area (JPA) which includes areas that may be developed beyond the 20-year planning period is not included in the study area, as these areas are not expected to require City sewer service within the next 20 years. An estimated 136 households within the current city limits are not connected to the City’s sewer system and are using on-site sewer systems. This equates to less than two percent of the City’s population. For the purpose of estimating future flows and loads, this Plan assumes that all currently unsewered areas will be served by the City within the 20-year planning horizon.

ES.3 EXISTING FACILITIES

The locations of the City’s existing wastewater facilities are shown in Figure ES.1. Existing facilities include two treatment plants, two effluent outfalls, approximately 74 miles of pipe, and 11 wastewater lift stations.

ES.3.1 Existing Treatment Facilities

Wastewater flows and loads treated at the City’s existing RBC Plant are approaching permitted limits, triggering the need for this Plan. Portions of the RBC Plant are over 50 years old and have reached the end of their service life. In recent years the City has experienced an increasing number of mechanical failures at the RBC Plant, particularly for outdated treatment equipment that is no longer prevalent in the treatment industry. Various analyses completed prior to this Plan have concluded that there is little or no salvage value in the existing RBC Plant. Due to its age and condition, and an inability to meet future

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regulatory requirements using installed technology, alternatives presented in this Plan assume the existing RBC Plant will be abandoned and demolished.

The Seaplane Base Lagoon Plant (Lagoon Plant) was constructed and originally operated by NAS Whidbey to serve the Seaplane Base. In 1990 the City secured a 50-year lease from the Navy to operate the Lagoon Plant. Wastewater flows and loads treated at the Lagoon Plant are approaching permitted limits, triggering the need for this Plan. The current lagoon treatment process does not provide sufficient capacity to accommodate projected City growth. A capacity increase at the lagoons will trigger more stringent effluent standards that cannot be met with conventional lagoon treatment. Expansion or modification of the existing lagoons is infeasible due to surrounding environmentally sensitive areas. Due to capacity limitations, an inability to meet future regulatory requirements, access issues during flood events, and surrounding environmentally sensitive areas, alternatives presented in this Plan assume the existing Lagoon Plant will not be used in the future to treat wastewater from the City’s collection system.

ES.3.2 Existing Effluent Outfalls

Historically, effluent treated at the RBC Plant was discharged through an 18-inch diameter corrugated metal pipe outfall and diffuser into Oak Harbor, terminating at approximately minus 15 feet mean lower low water (MLLW). The diffuser has had a history of sediment buildup and blockage. In the summer of 2010 a significant portion of the diffuser was found to be filled with sediments. In September 2010 the outfall failed and was abandoned. Since that time all flow treated at the RBC Plant has been pumped to the Lagoon Plant.

Effluent treated at the Lagoon Plant is currently discharged through an 18-inch diameter concrete pipe outfall and diffuser into Crescent Harbor, terminating at approximately minus 15 feet MLLW. The outfall was inspected in October 2010. Several sections of leaking pipe and joints were identified at that time. Portions of the pipe and diffuser will need to be repaired, replaced, and up-sized if the outfall is used as a component of the City’s future wastewater system.

ES.3.3 Existing Wastewater Collection System

The collection system was analyzed in previous planning efforts to determine the capacity of the existing network and to identify other issues that would trigger upgrades or improvements over the next 20 years. The results indicate a maximum peak hour flow of 7.9 million gallons per day (mgd) would be generated in the collection system discharging to the City’s existing RBC plant. Additionally, approximately 2 mgd of peak flow is generated on the Seaplane Base. The sum of these peak hour flows (9.9 mgd) provides the basis for peak hydraulic treatment capacity under current conditions.


Potential capacity limitations were identified in portions of the sewer system, and certain segments of the existing collection system were identified as being under-capacity for current flows. However, no segments require upgrades in the initial years of planning unless flow from the Navy is routed to existing gravity pipe segments that are near capacity. The timing for collection system capacity improvements is evaluated as a component of the alternatives analysis presented in this Plan.

ES.4 WASTEWATER FLOWS AND LOADS

Influent flow is derived from residential and commercial sources that discharge to the City’s RBC Plant, and from the Seaplane Base. There are no significant industrial sources in the City’s service area. Existing data were analyzed to determine current flows and loads on a total and per-capita basis. Future flows and loads were projected using current per-capita values and estimates for future population that are consistent with the City’s comprehensive planning documents.

ES.4.1 Flow and Load Projections

Existing and projected population data are shown in Table ES.1. Current wastewater flows and loads are shown in Table ES.2 and project wastewater flows and loads are shown in Table ES.3.

Table ES.1 Population Projections Wastewater Facilities Plan City of Oak Harbor

Year City Navy Seaplane

Base(1) UGA Sewered(2) Total

2000 15,395(3) 4,400 0 19,795(4)

2010 17,675(3) 4,400 0 22,075(4)

2030 23,776 4,400 731 28,907

2060 36,654 4,400 1,637 42,691

Notes: (1) Summarized from the City of Oak Harbor Comprehensive Sewer Plan (Tetra Tech,

December 2008) Table 3-2. (2) Assumes the UGA is not served currently and will be linearly incorporated into the service

area from 2012 through 2060. (3) Total flow minus Navy flow. (4) US Census data (2010).


Table ES.2 Current Flows and Loads Wastewater Facilities Plan City of Oak Harbor

Parameter City Total

Flow, mgd(1)

BWF 1.4 1.8

AAF 1.7 2.1

MMF 2.3 3.0

PDF 3.4 4.7

PHF 7.9 9.9

BOD, ppd(2,3) AA 3,556 4,127

MM 4,412 5,049

PD 5,556 6,510

TSS, ppd(2,4) AA 2,931 3,371

MM 4,153 4,792

PD 7,383 8,373

NH3, ppd(2,5) AA 390 487

MM 470 586

PD 596 745

Notes: (1) Total flow includes both City flow and flow from Navy facilities. Since the Navy population is

projected to remain constant through 2060, the Navy flows are projected to equal 0.37 mgd for BWF, 0.43 mgd for AAF, 0.65 mgd for MMF and 1.23 for PDF.

(2) Total load includes load from both the City and the Navy facilities. (3) The Navy BOD load is projected to equal 514 ppd for AA, 732 ppd for MM, and 942 for PD. (4) The Navy TSS load is projected to equal 440 ppd for AA, 638 ppd for MM, and 990 ppd for PD. (5) The Navy NH3 load is projected to equal 84 ppd for AA, 110 ppd for MM, and 128 ppd for PD.


Table ES.3 Projected Flows and Loads Wastewater Facilities Plan City of Oak Harbor

Parameters 2030 2060

City Total City Total

Flow, mgd(1)

BWF 1.9 2.3 3.0 3.4

AAF 2.4 2.8 3.7 4.1

MMF 3.2 3.9 5.0 5.7

PDF 4.6 6.0 7.4 8.6

PHF 9.0 11.0 11.4 13.4

BOD, ppd(2,3) AA 4,931 5,444 7,704 8,217

MM 6,117 6,849 9,557 10,290

PD 7,704 8,646 12,037 12,979

TSS, ppd(2,4)

AA 4,064 4,504 7,704 6,789

MM 5,759 6,397 9,557 9,636

PD 10,237 11,227 12,037 16,984

NH3, ppd(2,5)

AA 541 638 845 942

MM 651 768 1,017 1,134

PD 827 975 1,292 1,440

Notes: (1) Total flow includes both City flow and flow from Navy facilities. Since the Navy population is

projected to remain constant through 2060, the Navy flows are projected to equal 0.37 mgd for BWF, 0.43 mgd for AAF, 0.65 mgd for MMF and 1.23 for PDF.

(2) Total load includes load from both the City and the Navy facilities. (3) The Navy BOD load is projected to equal 514 ppd for AA, 732 ppd for MM, and 942 for PD. (4) The Navy TSS load is projected to equal 440 ppd for AA, 638 ppd for MM, and 990 ppd for PD. (5) The Navy NH3 load is projected to equal 84 ppd for AA, 110 ppd for MM, and 128 ppd for PD.

Population projections for the City are based on the City’s Draft Water System Plan. Navy population (and associated flows and loads) on the Seaplane Base are assumed to be constant over the planning period. Future flow and load projections also assume that the UGA will be uniformly incorporated into the sewer service area by Year 2060.

ES.4.2 Phasing Scenarios For Growth

Throughout this planning effort, year 2060 flows and loads are used to determine “ultimate” land area requirements for a WWTP that will serve the City’s needs well into the future. Year 2030 flows and loads are used to size and compare alternatives on a capital and life-cycle cost basis. The actual rate of growth of the City’s population, and corresponding increases in flows and loads, will likely be different than the values used for planning. To


account for these potential differences, phasing options are developed for the selected alternative to achieve the right balance between reliable capacity and affordability. Figure ES.2 shows the range of growth scenarios used for this analysis. Phase 1 facilities proposed in this Plan are based on the moderate growth scenario (approximately one percent annual growth in City population).

ES.5 REGULATORY REQUIREMENTS

Recognizing that the City is connected to the waters of Puget Sound via Oak Harbor and Crescent Harbor, the City’s goal is to obtain the highest level of water quality practical while recognizing the limitations of the rate payers of the City to fund improvements. A primary goal of the City is the continued protection of the water quality of the waters in and around Oak Harbor, thereby meeting the goals outlined in the Puget Sound Action Plan developed by the Puget Sound Partnership for the Cleanup and Protection of Puget Sound.

ES.5.1 Effluent Quality Goals

The City has established the effluent quality goals for conventional pollutants that are more stringent than the City’s current NPDES permit limits. These effluent goals are summarized in Table ES.4.

Table ES.4 Effluent Quality Goals Wastewater Facilities Plan City of Oak Harbor

RBC Plant NPDES Permit Limit

Lagoon Plant NPDES Permit Limit

New Facilities Target / Goal

TSS 30 mg/L 75 mg/L 10 mg/L

85% removal 85% removal 95% removal

CBOD5 25 mg/L 25 mg/L 10 mg/L

85% removal 85% removal 95% removal

Turbidity Not applicable Not applicable 1 NTU

Chlorine Residual 0.114 mg/L 0.5 mg/L No discharge

Fecal Coliform 200/100 mL 200/100 mL <100/100 mL

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Alternatives are evaluated largely on their ability to meet current NPDES permit limits. However, the flexibility to adapt to future regulatory requirements is an important planning consideration for the City. Potential future NPDES permit limits considered in this analysis include the ability to meet nutrient (nitrogen) limits and potential future trace organic chemical (TOrC) limits. While it is not yet clear how Ecology will establish future limits on these or other parameters, a number of Western Washington municipalities have begun to evaluate future nitrogen removal. In evaluating alternatives for Oak Harbor, the City is considering the need to meet a TIN level of 8 mg/L in the future, should these limits be enforced in subsequent permit cycles. Also, the City is interested in technologies that have demonstrated some ability to reduce TOrC concentrations in treated effluent, such as the MBR process or AS process with an extended solids residence time (SRT).

ES.5.2 Biosolids Management

The federal document that regulates the use and disposal of sewage sludge is the CFR, Part 503 (40 CFR §503, EPA 1993). Land-applied biosolids must meet requirements in the Part 503 regulations for reducing pathogens and vector attraction. The rule establishes two basic classes for pathogen reduction: Class A and Class B. The City is considering alternatives that will meet the 503 requirements for Class B initially, and Class A in future phases.

ES.5.3 Other Environmental Documents

The City has adopted the policies of the State Environmental Policy Act (SEPA) by reference (OHMC 20.04.010). A SEPA review will be completed to ensure that there are no adverse environmental impacts from proposed projects. The City will issue a threshold determination as to whether significant environmental impact may be expected as a result of the projects recommended by this Plan. This determination will be sent to Ecology for concurrence.

To be eligible for financial assistance from the State Water Pollution Control Revolving Fund, this Plan must also comply with the State Environmental Review Process (SERP; WAC 173-98-100). The SERP was established “to help ensure that environmentally sound alternatives are selected and to satisfy the state’s responsibility to help ensure that recipients comply with the NEPA and other applicable environmental laws, regulations, and executive orders.” Other environmental components of this Plan include a Biological Assessment (BA) that will be submitted to the Corps of Engineers, as well as documents prepared in accordance with Section 106 of the National Historic Preservation Act (NHPA).


ES.6 ALTERNATIVES DEVELOPMENT AND EVALUATION

Alternatives presented in this Plan are comprised of three components: 1) a Wastewater Treatment Process; 2) an Effluent Discharge (Outfall) Location; and 3) a Wastewater Treatment Facility Site. At the onset of the Project, the City took a position that all sites, outfall locations, and treatment processes should be considered potentially viable.

The project team used a comprehensive process to develop project objectives and evaluation criteria; and to identify and screen alternatives. The process generally consisted of major milestones between December 2010 and August 2012. Community input was a critically important factor in the development, evaluation and selection of alternatives. The City began proactively working with stakeholders in November of 2010 and continues to integrate a high level of community input to implement the proposed alternative.

ES.6.1 Project Objectives and Evaluation Criteria

The City’s 2009 Comprehensive Plan states that the City “…recognizes the value of its natural environmental and supports environmental protection and enhancement. The community recognizes that total preservation may not be feasible in an urban area. Rather, the City should seek to implement environmental goals within the context of planned growth.” To reflect the City’s values, the project team evaluated alternatives for upgrading the City’s wastewater treatment system considering impacts and benefits of the project to the community as a whole. The Triple Bottom Line is a commonly used approach that weighs three areas of cost and benefit: financial, social, and environmental. The category of “Technical” was included in this analysis to address industry standards in related to performance, implementability, operations, and maintenance. The approach of combining these four perspectives is referred to herein as “TBL+”.

For this evaluation, each of the four TBL+ categories was divided into three, equally weighted objectives. City staff meetings, stakeholder workshops, and community interviews were completed to establish project objectives and evaluation criteria for comparing alternatives. A summary of the TBL+ objectives and criteria is illustrated in Figure ES.3.

ES.6.2 Preliminary Alternatives

After a preliminary evaluation, the City selected two wastewater treatment processes as the basis for alternatives development: a membrane bioreactor (MBR) process and an activated sludge (AS) process with tertiary treatment. Analysis of outfall locations was also completed early in the Project. Oak Harbor was determined to be the most cost-effective and preferred location, largely to eliminate the risk of impact fees that could be assessed through the aquatic land use lease process. Once these decisions had been made, the process of developing and evaluating alternatives was focused on selecting a site for the City’s new treatment facility.

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PROJECT OBJECTIVES FIGURE ES.3

CITY OF OAK HARBOR



ES.6.3 Initially Proposed Sites

In December 2010, stakeholder and community input was used to identify 22 sites illustrated by the yellow dots on Figure ES.4. Two additional sites were added based on public input received later in the process (illustrated by yellow triangles on the figure). Over the next several months the Project team considered public input and technical criteria to develop 13 preliminary alternatives on eight potential sites, shown in blue on Figure ES.4.

Following the March 2011 City Council meeting, the project team completed an initial TBL+ evaluation of 13 preliminary alternatives (shown in Figure ES.5), generated by combining the eight potential sites with the two potential treatment processes options, each discharging to Oak Harbor. In the spring of 2011, additional coordination between the City and US Navy resulted in one previously identified site (Crescent Harbor) being added back to the list of potential sites. Over the next six months, the Project team conducted a series of public involvement efforts additional technical analysis, and coordination with the US Navy. During this time, the City was approached by the owners of property inside of the UGA and adjacent to Crescent Harbor Drive. As a result of the discussions that followed, the City elected to add this site (Crescent Harbor North) to the sites being considered. Figure ES.6 shows the six sites proposed for further evaluation. They include:

Windjammer Park

Marina/Seaplane Base

Old City Shops

Beachview Farm

Crescent Harbor

Crescent Harbor North

To better illustrate differences between the six sites being considered further, the TBL+ analysis was modified to compare all alternatives on an equal basis (i.e. assuming MBR process discharging treated effluent to Oak Harbor). Figure ES.7 shows the modified TBL+ comparison of the refined alternatives. Based on this analysis, the City elected to complete a more detailed comparison of three final alternatives:

Windjammer Vicinity MBR

Crescent Harbor North MBR

Crescent Harbor North AS

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ES.6.4 Final Sites and Alternatives

The two final sites selected by the City for further evaluation provide diversity with respect to location and non-cost challenges and opportunities. Additional technical analysis was completed to refine and update costs, focusing on differences between sites. Additional community input was also solicited to assist in refining alternative layouts and to better determine community perceptions related to non-cost factors.

In June 2012, the City collected additional community involvement using a two-day charrette process facilitated by a third-party. The first day of the charrette was focused on the Windjammer Vicinity; the second day was focused on Crescent Harbor North. In addition to City and consultant team staff, the charrettes were attended by 15 Oak Harbor community members. Participants were chosen to represent diverse opinions and issues ranging from neighborhood impacts, business needs, coordination with transportation, and overall quality of life in the community. The goal of the charrette process was to answer the question:

“If a new treatment facility was to be located in this location, how could it best be designed and located to provide the greatest overall community value?”

Figures ES.8 and ES.9 illustrate the results of the charrette process for the Windjammer Vicinity and Crescent Harbor North, respectively. Following the charrette process, the Project team further refined technical assumptions and associated costs associated with the three final alternatives, including a more detailed analysis of site-specific technical factors. Tables ES.5, ES.6, and ES.7 summarize the analysis and information presented for the three final alternatives. The Crescent Harbor North AS alternative has the lowest project cost ($89.0 million). Estimated project costs for the other two final alternatives are within five percent of this ($93.5 million). Annual O&M costs for the Crescent Harbor North alternatives are higher, reflecting approximately $170,000 per year in O&M cost for wastewater and effluent conveyance. The NPV of all three alternatives are within five percent of one another.


Street view looking North from park past future re-aligned Bayshore Drive

WINDJAMMER VICINITY CHARRETTE RESULTS

FIGURE ES.8

CITY OF OAK HARBOR


CONCEPTUAL AREA

CONCEPTUAL SITE PLAN

CONCEPTUAL RENDERING


Street view looking Northeast from Torpedo Road.

CRESCENT HARBOR NORTH CHARRETTE RESULTS

FIGURE ES.9

CITY OF OAK HARBOR


CONCEPTUAL AREA

CONCEPTUAL SITE PLANS

CONCEPTUAL RENDERING


Table ES.5 Windjammer Vicinity MBR Key Considerations Wastewater Facilities Plan City of Oak Harbor

Consideration Comments

Estimated Project Cost

Phase 1 Facilities

Year 2030 Facilities

$81.1 million

$93.5 million

20-Year NPV of Annual O&M(1) $20.3 million ($1.6 million/year)

Total 20-Year NPV $113.8 million

Ability to Phase Phase 1 costs assume continued use of Seaplane Lagoon for solids (high risk assumption)

Community Considerations Potential benefits to Windjammer Vicinity open space and transportation

Notes:

(1) O&M costs include power, chemicals, labor, equipment replacement, and solids handling.

Table ES.6 Crescent Harbor North MBR Key Considerations Wastewater Facilities Plan City of Oak Harbor



Phase 1 Facilities


n/a $93.5 million

20-Year Net Present Value (NPV) of Annual O&M(1)

$22.4 million ($1.8 million/yr)


Ability to Phase Alternative does not allow for component, performance, or conveyance phasing

Community Considerations Potential benefits to regional utility services and transportation

Notes:

(1) O&M costs include power, chemicals, labor, equipment replacement, solids handling, and maintenance of the pump stations and pipelines used to convey flow between Windjammer and Crescent Harbor North.


Table ES.7 Crescent Harbor North AS Key Considerations Wastewater Facilities Plan City of Oak Harbor



Phase 1 Facilities


$78.0 million

$89.0 million

20-Year Net Present Value (NPV) of Annual O&M(1)

$20.9 million ($1.7 million/yr)


Ability to Phase Phase 1 costs assume facilities for nitrogen removal and filtration are deferred (moderate risk assumption)

Community Considerations Potential benefits to regional utility services and transportation

Notes:

(1) O&M costs include power, chemicals, labor, equipment replacement, solids handling, and maintenance of the pump stations and pipelines used to convey flow between Windjammer and Crescent Harbor North.

ES.7 PROPOSED ALTERNATIVE

Considering final cost information and non-cost opportunities and challenges, the City Council passed Resolution 12-17 on August 14, 2012 identifying the Windjammer Vicinity MBR with a marine discharge to Oak Harbor as the alternative for further environmental review. There are two scenarios for implementing the proposed alternative:

Scenario 1: Under this scenario, the City will continue to provide treatment for wastewater generated within the City’s collection system and from the Seaplane Base.

Scenario 2: Under this scenario, the City will only provide treatment for wastewater generated within the City’s collection system.

ES.7.1 Wastewater Treatment Facility

Figure ES.10 shows a process schematic of the proposed MBR treatment facility, which includes the major process and non-process components listed below. Estimated costs for the treatment facility are summarized in Table ES.9.

Influent diversion and piping.

Influent pump station, flow measurement and sampling.

Influent coarse screening and grit removal.

Flow equalization.


Influent fine screening.

Aeration basins, aeration blowers, MBR tanks, and associated mechanical equipment.

Disinfection facilities. Preliminary alternative sizing and costs are developed based on UV disinfection, which is a requirement due to footprint constraints on the site.

Effluent storage and outfall piping.

Aerated storage for stabilized waste activated sludge (WAS) storage.

Solids dewatering.

Lime stabilization to Class B.

Thermal drying to Class A (future).

Ancillary and non-process facilities (chemical storage, odor control, administration/operations, and electrical).

ES.7.2 Wastewater Conveyance System

The need for conveyance system improvements associated with the Project is tied to the Navy’s participation. Conveyance system improvements required for Scenario 1 are shown in Figure ES.11. Estimated costs for collection system improvements are summarized in Table ES.9. There are no conveyance system improvements required within the planning period for Scenario 2.

ES.7.3 Treated Effluent Outfall

The proposed outfall will be along the existing outfall alignment into Oak Harbor. Estimated costs for outfall improvements are summarized in Table ES.9.

ES.7.4 Project Phasing Scenarios

Because of its location in the Windjammer Vicinity, future “heavy-civil” construction projects to expand the WWTP are not feasible. The majority of building structures, concrete tanks, etc. must be constructed to accommodate future expansions. However, the City is able to phase-in capacity to reduce the cost impact on current sewer customers. Capacity can be phased-in through the purchase of treatment process equipment (such as membranes and UV reactors). Pumps, screens, major pipe runs, and other process equipment can also be initially “right-sized” to accommodate an initial phase, and up-sized in the future as needed to accommodate growth.

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In addition to Navy participation, the rate of City growth will impact selection of Phase 1 capacity. Current maximum monthly flow is approximately 3.0 mgd (2.3 mgd from the City, and 0.7 mgd from the Navy’s Seaplane Base). If the City grows at the rate anticipated in the Comprehensive Plan, the maximum monthly flow required by Year 2030 will be approximately 3.9 mgd. This projected value includes Navy flow, which is assumed to be held constant at 0.7 mgd throughout the planning period. A moderate City growth scenario will result in a required capacity of approximately 3.4 mgd by Year 2030 (assuming a fixed 0.7 mgd from the Navy).

The City has selected the moderate growth scenario as a basis for Phase 1 capacity sizing. If the Navy continues as a customer and receives sewer service from the City (Scenario 1), Phase 1 capacity will be 3.4 mgd. If the Navy chooses to provide wastewater service for Navy flows independent from City facilities (Scenario 2), the City’s Phase 1 capacity will be 2.7 mgd. The Navy will select their preferred scenario for sewer service based on information included in this Plan as well as independent analysis. The City anticipates a decision from the Navy by July 2013.

Table ES.8 summarizes the required capacity for the Moderate Growth option (3.4 mgd Phase 1 capacity), with and without Navy participation.

Table ES.8 Phase 1 Capacity Summary Wastewater Facilities Plan City of Oak Harbor

Scenario City MM Flow Navy MM Flow Total MM Flow Navy Contribution

1) City + Navy 2.7 mgd 0.7 mgd 3.4 mgd 21%

2) City Only 2.7 mgd n/a 2.7 mgd 0%

ES.7.5 Phase 1 Cost Summary

Figure ES.12 and Table ES.9 summarize the estimated Phase 1 costs for both Scenarios 1 and 2. As shown, the total project cost for Scenario 1 is anticipated to be $82.6 million. The City’s share of this cost would be approximately $60 million, and the Navy’s share would be approximately $22.6 million. The total project cost for Scenario 2 is anticipated to be $67.7 million; 100 percent of this cost would be covered by the City.

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Table ES.9 Total Phase 1 Cost Comparison (in millions) Wastewater Facilities Plan City of Oak Harbor

Component

Scenario 1

Scenario 2 Combined Costs

Navy Contribution

City Contribution

WWTP $72.0 $15.1 $57.0 $64.8

Conveyance $7.7 $7.0 $0.7 n/a

Outfall $2.9 $0.5 $2.4 $2.9

Total $82.6 $22.6 $60.0 $67.7

Cost Escalated to Mid Point

$96.3 $26.2 $70.1 $78.9

ES.8 IMPLEMENTATION PLAN

The proposed schedule to construct the Phase 1 project is shown in Figure ES.13. Preliminary design is anticipated to begin in the second quarter of 2013 and will likely extend through the second quarter of 2014. Final design will begin in the second quarter, and will likely extend through the second quarter of 2015. Ecology has established a December 2014 deadline for submitting final plans and specifications for review. This deadline may be met through project packaging and alternate delivery methods. If the entire project is delivered in a single design-bid-build package, the December 2014 deadline will likely need to be extended. In any event, construction is anticipated to begin in the fourth quarter of 2014, with final facilities being completed by the end of 2017.

ES.8.1 Financial Analysis Summary

Cash expenditure estimates during design and construction phases were developed for both Phase 1 scenarios and used to model rate impacts. Under Scenario 1, it is assumed that the Navy will obtain the necessary capital funding for their share of the project. The City’s share of Scenario 1 capital costs are summarized in Table ES.10. These costs include construction and “soft costs” such as engineering, legal, and administrative costs. Project cost estimates summarized in Table ES.10 are escalated to the mid-point of construction, which is anticipated to be the Summer of 2016.

The total impact on City of Oak Harbor annual costs is estimated by considering two elements: 1) annual debt service; and 2) additional costs for operating the new WWTP. Annual cost impacts were estimated and several scenarios were run in the rate model to demonstrate corresponding impact on monthly rates, which are illustrated as a range of rate curves. The exercise shows estimated monthly rates for each scenario if all other variables


PROPOSED SCHEDULE

FIGURE ES.13

CITY OF OAK HARBOR WASTEWATER FACILITIES PLAN


Table ES.10 City Share of Phase 1 Capital Costs (escalated, in millions) Wastewater Facilities Plan City of Oak Harbor

Scenario 2013 2014 2015 2016 2017 TOTAL

Scenario 1 $1.1 $3.6 $3.3 $25.2 $36.9 $70.1

Scenario 2 $1.1 $4.1 $3.8 $28.4 $41.5 $78.9

included in the Rate Study remained the same. The City is beginning a rate review that may consider other changes to the budget not related to the proposed project.

Three scenarios were evaluated to provide a range of potential rates compared to the Rate Study Base Case:

Scenario 1: (City + Navy) was run at current reasonable borrowing assumptions (30 years at 4.5 percent interest);

Scenario 2A: (City Only) was run at current reasonable borrowing assumptions (30 years at 4.5 percent interest);

Scenario 2B: (City Only) was run with higher borrowing assumptions (20 years at 6.0 percent interest).

As shown in Figure ES.14, Scenario 1 results in an estimated monthly rate of $83.26, which compares to a Rate Study Base Case of $92.20. Scenario 2A is estimated at $90.48, which is also lower than the Base Case and reflects current, reasonable borrowing assumptions. Moving forward, the City has several options to reduce rate impacts including:

Be vigilant in maintaining sewer reserves for the proposed project.

Seek out grants or appropriations.

Follow grant and loan programs to see if they may provide favorable assistance.

Consider adjusting the SDC for new connections to reflect the estimated project costs included in this Plan.

Engage underwriting assistance or Financial Advising services early to seek bond structuring that will meet the rate plan and be as efficient as possible.

Maintain recommended rates from the Rate Study to help keep the later year rates as low as possible.

Conduct annual rate reviews and update the rate model every couple of years when preparing to borrow for the proposed Phase 1 Project.

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Year 4

Year 5

Year 6

Year 7

Year 8

Year 9

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$40.00

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$72.85

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$62.56

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$75.69

$83.26

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$57.50

$64.40

$72.13

$80.78

$90.48

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$47.00

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$59.48

$68.11

$77.99

$89.68

$107.62

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Volume i executive summary

Documents

Transcript of Volume i executive summary