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Engineering Report

Illahee/Oyehut Sewer Collection System Grays Harbor County, Washington

Gibbs & Olson Project No. 0355.0015

Prepared By:

April 2013

CERTIFICATE OF ENGINEER

Engineering Report

Illahee/Oyehut Sewer Collection System Grays Harbor County, Washington

April 2013

The technical material and data contained in this report were prepared under the supervision and direction of the undersigned, whose seal as a professional engineer licensed to practice as such, is affixed below.

Michael N. Olden, P.E. Project Manager Gibbs & Olson, Inc.

Grays Harbor County i Table of Contents Illahee/Oyehut Sewer Collection System April 2013 Engineering Report Gibbs & Olson, Inc.

TABLE OF CONTENTS Page No.

SECTION I – Project Purpose and Approach Project Purpose .............................................................................................................. I-1 Approach...................................................................................................................... I-1 Related Documents, Standards and Design Criteria .................................................................. I-2 SECTION II – CONDITIONS IN THE PLANNING AREA Zoning ........................................................................................................................ II-3 Physical Conditions in the Planning Area .............................................................................. II-3

Topography............................................................................................................. II-4 Soils ...................................................................................................................... II-4 Climate.................................................................................................................. II-4 Air Quality ............................................................................................................. II-4 Flood Plains ............................................................................................................ II-5 Wetlands................................................................................................................ II-5 Shorelines............................................................................................................... II-5 Groundwater........................................................................................................... II-6 Surface Waters......................................................................................................... II-6 Flora and Fauna ........................................................................................................ II-6 Historical and Cultural Resources.................................................................................. II-6

Existing Water System ............................................................................................... II-7 Other Services ......................................................................................................... II-7 Population and Sewage Flow............................................................................................. II-7 Current Population and Flow Estimates .......................................................................... II-7 Future Population and Flow Projections.......................................................................... II-8 Future Wasteloads ........................................................................................................II-11 SECTION III – EXISTING FACILITIES Existing Collection System .............................................................................................. III-1 SECTION IV – NEED FOR THE PROJECT Current On-Site Sewage Issues ......................................................................................... IV-1 Shellfish Protection........................................................................................................ IV-2 SECTION V – EVALUATION OF ALTERNATIVES Vacuum Sewer Collection System Alternative........................................................................ V-1

Vacuum Sewer Collection System Flow and Sizing............................................................. V-2 Vacuum Sewer Collection System Cost........................................................................... V-4

Low Pressure Sewer Collection System Alternative ................................................................. V-4 Low Pressure Sewer Collection System Flow and Sizing ...................................................... V-6 Low Pressure Sewer Collection System Cost .................................................................. V-10

Operation Costs and Rates ............................................................................................. V-11

Grays Harbor County ii Table of Contents Illahee/Oyehut Sewer Collection System April 2013 Engineering Report Gibbs & Olson, Inc.

TABLE OF CONTENTS (Continued) Page No.

SECTION VI – SELECTION OF AN ALTERNATIVE Net Present Worth........................................................................................................ VI-1 Recommended Project ................................................................................................... VI-2 SECTION VII – PROPOSED PROJECT Project Description ...................................................................................................... VII-1 Project Cost Summary................................................................................................... VII-4 Project Financing ......................................................................................................... VII-4

Ecology Funding Programs ........................................................................................ VII-5 Rural Development Funding ...................................................................................... VII-6 Community Development Block Grant Program ............................................................. VII-6 Utility Local Improvement District (ULID).................................................................... VII-6

Operating Costs and Rates.............................................................................................. VII-8 Project Schedules and Implementation ............................................................................... VII-9 APPENDICES Appendix A – Cost Estimates

Vacuum Sewer Collection System Cost Estimates Low Pressure Sewer Collection System Cost Estimates

Appendix B – Low Pressure Collection System Hydraulic Model Results Appendix C – Net Present Value Analysis

OMB Circular a-94 “Appendix C” Seattle Area CPI Projections Net Present Value Vacuum Sewer Collection System Net Present Value Low Pressure Sewer Collection System

Grays Harbor County iii Table of Contents Illahee/Oyehut Sewer Collection System April 2013 Engineering Report Gibbs & Olson, Inc.

LIST OF FIGURES Page No.

II-1 Vicinity Map ................................................................................................... II-1 II-2 Illahee/Oyehut Planning Area ............................................................................. II-2 II-3 Zoning .......................................................................................................... II-3 II-4 Wetlands ....................................................................................................... II-5 III-1 Existing City Collection System .......................................................................... III-1 IV-1 Shellfish Protection District Map .......................................................................... IV-2 V-1 Vacuum Collection System Piping Schematic ........................................................... V-3 V-2 Low Pressure Collection System Piping Schematic .................................................... V-9 VII-1 Low Pressure Collection System Project ............................................................... VII-2 LIST OF TABLES

Page No.

II-1 Current Development Characteristics ..................................................................... II-7 II-2 Current Sewage Flow Estimates (gpd) .................................................................... II-8 II-3 Future Development Characteristics....................................................................... II-9 II-4 Future Sewage Flow Projections (gpd) ...................................................................II-10 II-5 Peak Hour Sewage Flow (gpd) at Various Growth Rates .............................................II-11 V-1 Grinder Pump Flow Projections for the Oyehut Sub-Area ............................................ V-6 V-2 Grinder Pump Flow Projections for the Illahee and Large Lots Sub-Area .......................... V-7 V-3 Capital Cost Summary...................................................................................... V-10 V-4 O&M Cost Summary ....................................................................................... V-11 V-5 Estimated Average Monthly User Rates................................................................. V-12 VI-1 Net Present Value of Collection System Alternatives ................................................. VI-1 VII-1 Project Cost Summary...................................................................................... VII-4 VII-2 Estimated Property Assessments.......................................................................... VII-7 VII-3 Estimated Monthly and Annual Payments for Assessments .......................................... VII-8 VII-4 Anticipated Project Tasks and Milestones..............................................................VII-10

Grays Harbor County I - 1 Section I- Project Purpose and Approach Illahee/Oyehut Sewer Collection System April 2013 Engineering Report Gibbs & Olson, Inc.

SECTION I PROJECT PURPOSE AND APPROACH

PROJECT PURPOSE The purpose of this Engineering Report is to provide guidance to Grays Harbor County (County) in providing centralized wastewater collection and treatment services for properties north of the City of Ocean Shores (City) referred to as the Illahee/Oyehut area. Current development in this area is now served by individual on-site sewage systems. This report has been prepared to conform with current State of Washington Department of Ecology (Ecology) regulations and guidelines. As such, this Engineering Report has been written to meet the requirements of Washington Administrative Code (WAC) 173-240-060. In anticipation of the potential for requesting funding from either Ecology of the United States Department of Agriculture (USDA) Rural Utilities Service (RUS), this Engineering Report has also been prepared to conform with RUS Bulletin 1780-3: “Preliminary Engineering Report - Wastewater Facilities”. This report may be used to process the funding request and should clearly describe the owner’s present situation, analyze alternatives and propose a specific course of action. The depth of analysis within the report is expected to be proportional to the size and complexity of the proposed project. Ecology and RUS applicants are expected to perform an environmental review concurrently with the project engineering planning. The required environmental review pursuant to 7 CFR Part 1794, guidance in RUS Bulletin 1794A-602: “Guide for Preparing the Environmental Report for Water and Waste Projects” is not included in the scope of work for this report and will be completed as a separate project after an alternative is selected and an implementation plan is solidified. APPROACH A primary objective of the report is to ensure adequate conveyance and treatment capacity is provided to meet the needs of the Illahee/Oyehut area, to ensure such facilities minimize adverse impacts on the environment, and to protect the health and safety of the affected community. An additional priority is to accomplish these goals in an economical and efficient manner. Minimum requirements for the collection system are set forth by Ecology, the City and the County in the form of rules, design guidelines and standards. The approach taken in preparation of this report is to:

• Define environmental and physical conditions in the planning area.

• Develop flow and wasteload projections.

• Describe existing facilities, capacity and constraints.

• Describe the need for the project.

• Evaluate alternatives to meet project needs

Grays Harbor County I - 2 Section I- Project Purpose and Approach Illahee/Oyehut Sewer Collection System April 2013 Engineering Report Gibbs & Olson, Inc.

• Describe the proposed project, costs and implementation plan. This report utilizes information obtained from the City and County, including “as-built” drawings and previous planning and design-related documents. Information provided by City and County staff concerning various systems and loading characteristics has been considered and included in this Plan. It is anticipated that this report will be reviewed by the City, Ecology, Stakeholders and applicable funding agencies. RELATED DOCUMENTS, STANDARDS AND DESIGN CRITERIA Criteria for Sewage Works Design (Orange Book) - Washington State Department of Ecology, August 2008 Wastewater Comprehensive and Capacity Update and Preliminary Wastewater Treatment Plan Facility Plan for the City of Ocean Shores, WA - Brown and Caldwell, May 2008 Engineering Report for Providing Sewer Service to the Oyehut/Illahee Area (Draft) - CH2M Hill, August 1995

Grays Harbor County II - 1 Section II - Conditions in the Planning Area Illahee/Oyehut Sewer Collection System April 2013 Engineering Report Gibbs & Olson, Inc.

SECTION II CONDITIONS IN THE PLANNING AREA

The Illahee/Oyehut area is approximately 175-acres of mixed use properties located just north of the City of Ocean Shores (City), between the City and Ocean City State Park. A vicinity map is shown on Figure II-1. The Illahee/Oyehut planning area is best described as the area between the City and State Park that does not currently have permanent City sewer service. The planning area is comprised of three distinct areas. The areas are referred to as Illahee, Large Lots and Oyehut. The Illahee/Oyehut planning area boundary is shown on Figure II-2. The Illahee sub-area is comprised of 7 commercial properties along Damon Road and 81 full time and part time residential properties north of the commercial areas. The residential properties are generally in the range of 5,000 to 50,000 square feet, with the majority (59 lots) falling between 10,000 and 20,000 square feet. The Large Lots consist of 7 properties (labeled A through G on Figure II-2). The larger properties, labeled A through D on Figure II-2, are each about 23 acres in size. The three properties to the far north vary in size from 2 to 10 acres. The existing building for Lot F is located at the end of Oyehut Road. The Oyehut Corporation is one property with 72 members. Seven of the 72 membership spaces are in the commercial area along Damon Road. The 65 units along Oyehut Road are a mixture of recreational cabins, permanent residences and part time residences.

Source: USGS

Figure II-1 Vicinity Map

Illahee/Oyehut Area

Scale (in Feet)

Damon Rd.

High

Sch ool

Beach Approach

Chic kam

in Ave.

Oyehut Rd.

Large Lots

Oyehut Corporation

Illahee

AB

CD

E

F

Illahee/Oyehut

Planning Area

G

Illahee/Oyehut Planning AreaFigure II-2


ZONING Land-use zoning within the planning area is shown on Figure II-3 and consists of General Commercial (C-2) and Resort Residential (R-3). The following is a discussion of the land uses allowed by County Code for the zoning designations within the planning area:

Resort Residential District (R-3): Permitted uses under R-3 include single and multi-family dwellings, parks, temporary or seasonal vending, and in-home day-care. Conditional uses include motels, mobile home parks, and campgrounds along with several other uses. Uses that are prohibited include convenience retail and industrial uses. The minimum lot size in R-3 ranges from 7,200 square feet for single family to, for example, 11,200 square feet for a 4-unit condominium or apartment building. Required lot size may also be dependent upon the sewage disposal method and water system type. Larger lot sizes are required when on-site septic systems are utilized. General Commercial (C-2):

Permitted uses under C-2 include all business and retail uses as well as storage buildings, motels, churches, auto maintenance, and accessory dwelling. The only conditional uses allowed under C-2 are day-care centers (with restrictions). Industrial uses, schools and residential are all prohibited in the C-2 areas. Single family residences accessory to a permitted commercial use and light industrial uses are also allowed. There is no minimum lot size for C-2.

PHYSICAL CONDITIONS IN THE PLANNING AREA The following is a discussion of the physical conditions within the planning area. This report provides a significant amount of information that will be used for environmental review. However, a full environmental review is not included in the scope of work for this report. Environmental work will be completed as a separate project after an alternative is selected and an implementation plan is solidified.

Planning Area

Source: Grays Harbor County Central Services

Figure II-3 Zoning


Topography The majority of the developed planning area is at an elevation of about 15 to 25 feet above sea level. The planning area is mostly flat with rolling dunes in the western areas. Soils According to Soil Survey of Grays Harbor County Area, Pacific County, and Wahkiakum County, Washington - 1986, USDA NRCS, the soils present in the developed areas within the planning area are primarily dune land (Map Unit 35). The map unit is described by NRCS as: This very deep, dominantly excessively drained land type consists of a ridge of dunes near the ocean shore, an interdune area, and a ridge of dunes inward from the ocean shore. Dunes nearer the shore generally form a narrow ridge that is 5 to 30 feet high and is parallel to the coastline. The interdune area is nearly level and has a water table that is at the surface during the rainy season. The dunes are constantly shifted by strong coastal winds. A commonly observed profile of Dune land is grayish brown fine sand to a depth of 60 inches or more. Included in this unit is about 10 percent Westport soils. Permeability of Dune land is dominantly very rapid. Available water capacity is low. Runoff is slow, and the hazard of water erosion is slight. The hazard of soil blowing is very severe. This unit is used for recreation and as homesites. This unit is poorly suited to homesite development. The main limitations are the hazard of soil blowing and the high water table in the interdune area. In some places, excavation for houses and access roads exposes material that is highly susceptible to soil blowing. Disturbed areas around construction sites should be revegetated as soon as possible to reduce soil blowing. Shifting sand can be stabilized by planting beachgrass followed by Scotch-broom and shore pine (fig. 15). In summer, irrigation is required for lawn grasses, shrubs, vines, shade trees, and ornamental trees. Mulch, fertilizer, and irrigation are needed to establish lawn grasses. If the density of housing is moderate to high, community sewage systems are needed to prevent contamination of water supplies as a result of seepage. This map unit is in capability subclass Vllle. The majority of development is and will be within the interdunal areas. The NRCS description appears accurate based on observation of construction projects in the area. Climate The summers are cool and comparatively dry while the winters are mild, wet, and cloudy. According to the Western Regional Climate Center (WRCC), rainfall averages about 90 inches annually, with over 10 inches per month occurring in November through February June, July and August are the driest months, averaging less than three inches of rain per month. The average daily temperature range is 43oF to 56oF. The average growing season is 200 to 240 days. Air Quality The Olympic Region Clean Air Agency (ORCAA) is a local government agency charged with regulatory and enforcement authority for air quality issues in Clallam, Grays Harbor, Jefferson, Mason, Pacific, and Thurston counties. The nearest air quality monitoring station to the planning area used by ORCAA to track air quality is in Aberdeen. Air quality from April 2011 to present is listed as good except for four days in December 2011, when air quality was listed in the moderate category.


Flood Plains The Federal Emergency Management Agency (FEMA) has defined the extent of the 100-year flood boundary in order to establish actuarial flood insurance rates and to assist communities in efforts to promote sound flood plain management. The western planning area is Zone B (outside the 100 year flood boundary, but within the 500 year flood boundary) and the eastern area is Zone C (area of minimal flooding). Wetlands The interdunal wetlands are classified as palustrine and riverine. These wetlands are present throughout the planning area as shown in Figure II-4. There is an extensive interdunal wetland along the western boundary of the planning area. The interdunal wetlands are generally valued for conservation due to frequent association with many rare and endangered plant species and their associated fauna. Grays Harbor County Code Title 18.06 provides rules for critical areas protection. The Critical Areas Ordinance (CAO) provided in Title 18.06 restricts or prohibits development in critical areas and utilizes protective buffers, usually of undisturbed native vegetation, to be designated around some critical areas. The CAO also identifies criteria and constraints for implementing utilities within critical areas. Shorelines The entire planning area is considered to be shoreline area and is subject to the Grays Harbor County Shoreline Master Program. Each development application other than single family and duplex dwellings must undergo a conditional use process. The Shoreline Master Program limits the impervious area for all development. The level of development allowed for conditional uses is

Source: U.S. Dept. Fish & Wildlife

Figure II-4 Wetlands

Planning Area


dependent upon the proximity to the dune protection zone. The range of allowable impervious surface for conditional uses is 15% to 35% of the total lot size. Groundwater Groundwater in the planning area is at or near the surface in many areas during the winter time. Local construction experience indicates that groundwater is within 2 feet to 3 feet of the surface in most existing right of way areas during the summer months. There are no public water supply wells or surface water withdrawals within the planning area. Public water system wells for the City and the County water systems are located several miles away. Surface Waters The riparian corridors in the planning area include interdunal wetlands and Oyehut Creek (also referred to as Oyehut Ditch or Oyehut Canal). Flora and Fauna The Washington State Department of Natural Resources (DNR) Ecological Integrity Assessment: North Pacific Coastal Interdunal Wetland (February 2002) provides the following assessment of flora and fauna within the interdunal wetlands that make up a majority of the undeveloped land within the planning area: “Distinct landform and vegetation patterns are common to these dune systems. Depending on moisture and salinity gradients, North Pacific Coastal Interdunal wetlands are colonized by herbaceous species such as Carex obnupta, Argentina egedii, Juncus lesueurii, Juncus falcatus ssp. sitchensis, Juncus nevadensis, Equisetum variegatum and various other emergent species resembling wet meadows or marshes (Weideman 1984). Shrubs such as, Salix hookeriana and S. sitchensis can be present particularly in older wetlands that gain characteristics of shrub swamps. The physical forms of dunes have been altered by European beachgrass (Ammophila arenaria), which has been extensively planted for stabilization purposes and has also spread widely on its own. Ammophila arenaria foredune stabilization decreases sand supply to backdune areas that leads to soil formation and an increase in invasive and native grassland, coastal scrub, and wetlands (Wiedemann and Pickart 2004). Unstabilized sand is now a relatively rare condition primarily because of the introduction of this species and many deflation plains are much larger than their historical extent. It is not clear how this may affect vegetation patterns relative to historical conditions, however without dynamic dune systems, the diversity of structure within interdunal wetlands may homogenize, with shrubby and/or forested wetlands predominating. “ Historical and Cultural Resources The planning area has a very high probability for cultural resources based on known historical use of the area and previous experience evaluating the potential for cultural resources for similar projects in the area. A Cultural Resources Technical Report will need to be completed after the preferred project alternative is selected. Pipe corridors will need to be adjusted to minimize potential affects on cultural resources. Areas that have been previously disturbed will be favored in selection of pipe corridors. Inadvertent discovery procedures and guidelines will need to be developed for construction activities.


Existing Water System The majority of the planning area receives water service from the Grays Harbor County Hogan’s Corner Water System (DOH ID #AA554). The existing water system infrastructure can currently deliver up to 1.87 million gallons per day (gpd). Measured peak flow available to the planning area is over 1,000 gallons per minute with a residual pressure of 60 psi. Static pressure in the planning area is in the range of 70 to 80 psi. The majority of the Large Lots sub area does not currently have water system infrastructure. Other Services Other utilities within the planning area include: telephone service by CenturyLink; electrical service by Grays Harbor Public Utility District (PUD); high speed internet by various providers and cable television service by Coast Communications. LeMay, Inc. provides weekly refuse and recycling service. There is no natural gas service to the area. The Grays Harbor County Sheriff provides police protection and the City, through an interlocal agreement with Grays Harbor Fire District #7, provides fire and emergency services. State Highway 109 is within 3 miles of the site and the nearest international airports are the SeaTac Airport located 120 miles east and another located in Portland, Oregon, 160 miles south. POPULATION AND SEWAGE FLOW Future projected sewage flow and wasteloads are estimated in this section of the report to provide a basis for design of collection system and treatment capacity necessary to accommodate existing development and future growth over the next 20 years. Current Population and Flow Estimates The planning area is broken down into sub areas to better define and estimate population and growth characteristics. The sub areas of the planning area are designated as “Illahee”, “Oyehut” and “Large lots”. The Large lots are further broken down into Large Lots A - D and large Lots E - G . Table II-1 presents the current development characteristics for each sub area.

Table II-1 Current Development Characteristics Properties Sub Area Developed Undeveloped Total Current ERUs Illahee 56 32 88 70 Oyehut 1 0 1 73 Large Lots A-D 0 4 4 0 Large Lots E-G 1 2 3 0 Total 58 38 96 143

Sewage flow characteristics for the planning area should be similar to sewage flow characteristics for similar uses within the City. Sewage flow and water use is strongly influenced by seasonal


recreation activities. The 2008 City Facility Plan identifies average sewage flow per residential sewer “unit” as 99 gpd in the summer and 114 gpd in the winter. These average residential flow values from the 2008 City Facility Plan will be utilized for Equivalent Residential Units (ERUs) in this report. Evaluation of recent water use data for the Illahee/Oyehut area identifies average summer (June through September) water use is about 90 gpd/ERU and average non-summer water use is about 70 gpd/ERU. The recent water use data supports the use of the 2008 City Facility Plan sewage flow estimates. Table II-2 presents the estimated sewage flow from current development in the planning area. The existing residence within Large Lot F will be served by the collection system for the Oyehut sub-area and is therefore included in the Oyehut sub-area flow projections.

Table II-2 Current Sewage Flow Estimates (gpd) Average Day Peak Day Peak Hourly Sub Area Summer Winter Summer Winter Summer Winter

Illahee 6,930 4,788 9,979 9,576 27,720 19,152 Oyehut 7,227 4,993 10,407 9,986 28,908 19,973 Large Lots A-D - - - - - - Large Lots E-G - - - - - - Total 14,157 9,781 20,386 19,562 56,628 39,125

Assumptions: 114 gpd, Average winter residential sewage flow per unit 99 gpd, Average summer residential sewage flow per unit 2 x Average winter flow = Winter peak day flow

1.44 x Average summer flow = Summer peak day flow 4 x Average flow = Peak hour flow (summer and winter)

60% Occupied in winter time

The factors utilized to convert average day sewage flow to peak day and peak hourly flow are based on the factors utilized in the 2008 City Facility Plan. The factors are consistent with Washington State Department of Ecology (Ecology) Orange Book design criteria for collection systems.

Future Population and Flow Projections Future population and flow estimates in the report are evaluated in regard to build out and growth rates. The timing and magnitude of development on larger Illahee properties and large lots is difficult to estimate. If estimates are too conservative, the final alternative may be more costly and capacity will never be utilized. However, if not enough capacity is planned for, costly upgrades may be required before the collection system has met the useful life of the facility. The larger lots within the Illahee commercial areas have had the same level of use for decades and may stay that way for future decades as well. However, as development pressure increases for creation of more lodging capacity, these areas may convert to moderate level hotel and/or


condominium use. Higher use for the Illahee commercial properties will only have a moderate impact on collection system alternatives since these areas are closest to existing City sewer infrastructure and will have the least hydraulic impact. The timing and scope of development for Large Lots A-D is very difficult to estimate. These lots will have to go through a reasonable use assessment, conditional use process and shoreline development process prior to implementing any development project other than a single family or duplex building. The possible higher use may be moderate sized hotel and/or condominium projects. The planning estimate of 100 ERUs per lot for Large Lots A-D is used as a moderate to high baseline level for hydraulic modeling of collection system alternatives. This results in about 4 ERUs per acre for the Large Lots sub area compared to about 5 ERUs per acre for Illahee and Oyehut sub-areas. A discussion of the collection system impacts from higher or lower development is provided in Section V of this report. For comparison, the 2008 City Facility Plan estimated 84 current sewer units and 155 future sewer units at build out for the Illahee/Oyehut area. These estimates did not include the large lots. The large lots were incorporated into estimates for service to the Hogan’s Corner area and were not broken out separately The estimates for this report are much more conservative than the 2008 City Facility Plan estimates. Planning area build out projections and assumptions are shown in Table II-3.

Table II-3 Future Development Characteristics Sub Area Future Sewer Units (ERUs) Illahee 223 Oyehut 116 Large Lots A-D 400 Large Lots E-G 15 Total 754

Assumptions:

20% Illahee Undeveloped at Build Out

150 ERU total Illahee commercial lot build out

66 total residential lot build out in Oyehut

50 ERU total Oyehut commercial build out

100 ERU average per lot build out for lage lots A-D

5 ERU average per lot build out for lage lots E-G

Future flow projections based on the estimated build out development characteristics are shown in Table II-4.


Table II-4 Future Sewage Flow Projections (gpd)

Average Day Peak Day Peak Hourly Sub Area Summer Winter Summer Winter Summer Winter Illahee 22,077 15,253 31,791 30,506 88,308 61,013 Oyehut 11,484 7,934 16,537 15,869 45,936 31,738 Large Lots A-D 39,600 27,360 57,024 54,720 158,400 109,440 Large Lots E-G 1,485 1,026 2,138 2,052 5,940 4,104 Total 74,646 51,574 107,490 103,147 298,584 206,294

Assumptions: 114 gpd, Average winter residential sewage flow per unit 99 gpd, Average summer residential sewage flow per unit 2 x Average winter flow = Winter peak day flow

1.44 x Average summer flow = Summer peak day flow 4 x Average flow = Peak hour flow (summer and winter)

60% Occupied in winter time

The combined projected peak hourly flow for Illahee and Oyehut (134,244 gpd) is comparable to the future build out flow projection of 115,000 gpd for the same sub-areas in the 2008 City Facility Plan. As discussed above, the 2008 City Facility Plan did not break out flow projections for the Large Lots sub-area. The timing for reaching build out conditions is difficult to predict. Current Washington State Office of Financial Management (OFM) estimates for growth in Grays Harbor County are very low compared to growth estimates provided in the 2008 City Facility Plan. The 2008 City Facility Plan estimates were determined at the height of the housing boom, prior to the latest recession and may be optimistic. The OFM estimates for the County estimates on the other hand, do not take into account the higher growth for the beach areas compared to growth in the rest of the County. Table II-5 shows the contrast of low, moderate and high growth rates for the planning area. The low growth rate is the current high OFM growth rate for the County. The high growth rate is the high growth rate from the 2008 City Facility Plan and the moderate growth rate is a rate that may better reflect the long term growth for unincorporated coastal areas outside City Limits. The current year flow is the peak hourly summer flow. Peak hourly summer flow is the basis for collection system sizing.


Table II-5 Peak Hourly Sewage Flow (gpd) at Various Growth Rates

Growth Rate Year Low Moderate High

2013 56,628 56,628 56,628 2018 58,058 61,004 68,897 2023 59,524 65,719 83,823 2028 61,027 70,798 101,984 2033 62,568 76,270 124,079 2038 64,148 82,164 150,961 2043 65,768 88,514 183,667 2048 67,428 95,355 223,459 2053 69,131 102,724 271,872 2058 70,877 110,663 330,774 2063 72,667 119,216

Assumptions:

0.5% Low Growth Rate

1.5% Moderate Growth Rate

4.0% High Growth Rate

Under the high growth rate scenario, build out would occur within about 40 years. Build out would not occur within the next 50 years under the low and moderate growth scenarios. FUTURE WASTE LOADS Waste loads for the planning area are expected to be consistent with the average waste loads projected for customers within the City as defined in the 2008 City Facility Plan. The estimated 5-Day Biochemical Oxygen Demand (BOD5) is 0.319 pounds per day per ERU in the winter and 0.282 pounds per day per ERU in the summer. The estimated Total Suspended Solids loading (TSS) is 0.263 pounds per day per ERU in the winter and 0.258 pounds per day per ERU in the summer.

Grays Harbor County III - 1 Section III - Existing Facilities Illahee/Oyehut Sewer Collection System April 2013 Engineering Report Gibbs & Olson, Inc.

SECTION III EXISTING FACILITIES

EXISTING COLLECTION SYSTEM The Illahee/Oyehut area does not have a centralized sewage collection system. The majority of the existing development within the planning area currently utilizes individual on-site sewage disposal systems. There are currently 3 properties within the planning area that receive temporary sewer service from the City of Ocean Shores (City). The high groundwater and sandy soil

conditions create very challenging conditions for installation of new on-site sewage systems or repair of existing systems. Characteristics of City sewage collection systems, treatment facilities and capacity are documented in the 2008 City Facility Plan. The 2008 City Facility Plan provides a discussion of hydraulic capacity of potential discharge locations that may be utilized by a sewer system serving the Illahee/Oyehut area. Sewer Basin PS-1 (Existing gravity basin shown in Figure III-1) is located in the northwest corner of the City just south of the Illahee/Oyehut planning area. The majority of the piping in Basin PS-1 is gravity concrete sewer pipe constructed in the early 1970’s. The 2008 City Facility Plan states that “Oyehut areas could be served by a single pump station (vacuum or conventional), with its own dedicated force main emptying into the City’s gravity system either at Ocean Shores

Source: 2008 City of Ocean Shores Facility Plan

Figure III-1 Existing City Collection System

MH 1-15

Grays Harbor County III - 2 Section III - Existing Facilities Illahee/Oyehut Sewer Collection System April 2013 Engineering Report Gibbs & Olson, Inc.

Boulevard or Damon Road.” Due to current hydraulic limitations, the 2008 City Facility Plan indicates that the existing gravity sewer mains in the vicinity of Damon Road and Point Brown Avenue that are connected to the existing gravity sewer main in the Oyehut Creek corridor cannot accept Illahee/Oyehut sewage flow without extensive pipe upgrades. A Point Brown Avenue gravity sewer project is proposed in the 2008 City Facility Plan as an upgrade to the Oyehut Creek line and that project is estimated to cost over $3.7 Million (2008 dollars). It is cost prohibitive for the relatively small service area to upgrade the Oyehut Creek sewer line. The 2008 City Facility Plan indicates that the Ocean Shores Blvd gravity sewer main to the west of Point Brown Avenue “has a flow capacity of 680,000 gpd at MH 1-15, in the cul-de-sac at its northwest corner, and exceeds 1 MGD [million gallons per day] for the rest of its length” The Ocean Shores Blvd gravity system discharges to MH 1-2 in Point Brown Avenue. MH 1-2 is downstream of the Oyehut Creek hydraulic issues and has an estimated hydraulic capacity of over 5 MGD total based on the discussion in the 2008 City Facility Plan. Pump Station No. 1 can accept up to 300 gpm (432,000 gpd) of additional flow prior to requiring upgrades. Current peak flow within Basin PS-1 is estimated to be 674,836 gpd winter (New Years) and 409,597 gpd summer (4th of July). The estimated peak flows for Basin PS-1 at build out conditions are 733,652 gpd winter and 541,361 gpd summer. The Facility plan does not indicate the estimated peak flow at specific manholes, but indicates that there is very little existing sewage flow contribution to the collection system at MH 1-15 at the north end of Ocean Shores Blvd. In summary, the gravity main at Ocean Shores Blvd has adequate capacity to accept current and projected sewage flow from the Illahee/Oyehut planning area. The 2008 City Facility Plan also indicates that the estimated sewage flow from the Illahee/Oyehut area will not significantly impact availability of treatment plant capacity or the timing of treatment plant improvements.

Grays Harbor County IV - 1 Section IV - Need for Project Illahee/Oyehut Sewer Collection System April 2013 Engineering Report Gibbs & Olson, Inc.

SECTION IV NEED FOR PROJECT

CURRENT ON-SITE SEWAGE DISPOSAL ISSUES Many of the septic systems in the Illahee/Oyehut planning area were installed decades ago when there was little or no regulatory oversight addressing their design, installation and maintenance. The poor condition of the on-site sewage disposal systems in the Illahee/Oyehut area and the effect of the on-site sewage disposal on public health and the environment has been an on-going concern. The earliest consideration of expansion of sewer service from the City of Ocean Shores (City) to the Illahee/Oyehut area was in a 1968 Ruskin Fisher Sewer Study & Engineering Report. Since that time, service to the area has been evaluated at some level in the 1980 City General Wastewater Plan, the 1990 City General Sewer Plan, a 1995 County Engineering Report and the 1995 City Wastewater Master Development Plan. In May of 1995, Resolution 95-55 was passed by Grays Harbor County (County) to designate the Ocean Shores sewer service area as an “area of special concern”. The resolution identified on-site sewage disposal as a potential public health risk in the area and requires property owners to either upgrade non-compliant on-site sewage disposal systems or connect to the City sewer system when it becomes available. In a July 2008 public meeting regarding the potential for City sewer in the Illahee/Oyehut area, the representatives of Illahee and Oyehut had concerns regarding: Bringing properties up to code to invest in the future and improve quality of life; safer living conditions without [sewage] contamination; property owner’s ability to obtain building permits to build new or upgrade current residences; and concern about future cost of sewer service if not done soon. City Staff at that time also added that installing the sewer system would help clean up waterways in the Oyehut and Illahee area. Grays Harbor County Environmental Health conducted an assessment of the on-site sewage systems in the Illahee and Oyehut areas in July 2011. The assessment was conducted in response to concerns regarding immediate health impacts from poor sewage disposal practices. Eighty water quality samples were collected as a part of the survey. The results of the assessment indicate that the majority of septic systems in the study area are considered to be “old” with some or all components inundated during the winter months and/or after moderate to heavy rainfall events. County Environmental Health staff provided recommendations for operation and repair for several on-site systems that were evaluated. County Environmental Health fully supports any effort to update sewage disposal capabilities in the area. SHELLFISH PROTECTION The Illahee/Oyehut area was recently included in a County Shellfish Protection District pursuant to Chapter 90.72 RCW (See Figure IV-1 below). Monitoring results from multiple water quality monitoring stations along the Pacific Coast growing area have water quality that exceed National Shellfish Sanitation Program (NSSP) Standards. When these standards are exceeded and non-point


sources of fecal loading are the principle contributors to water quality degradation, Washington State Law mandates the creation of a Shellfish Protection District. Water quality monitoring results from WQ Station #9 near the Oyehut Beach Approach off of Damon Road (just West of the planning area) have raised specific concerns regarding activities near that area. Additional testing has been conducted by the State Department of Health and preliminary indications are that the results from the additional testing will exceed National Shellfish Sanitation Program standards.

Source: Grays Harbor County - Department of Public Services

Figure IV-1 Shellfish Protection District Map

Illahee/Oyehut Planning Area


In summary, this project is needed to: Protect public health related to shellfish protection and environmental exposure; protect the environment from the effects of inadequately treated sewage; and provide current property owners the means to beneficially use and develop their property.

Grays Harbor County V - 1 Section V - Evaluation of Alternatives Illahee/Oyehut Sewer Collection April 2013 Engineering Report Gibbs & Olson, Inc.

SECTION V EVALUATION OF ALTERNATIVES

The basic sewer collection system alternatives for most sewer systems include: Gravity sewers with lift stations; vacuum station and vacuum collection system; low pressure collections system with grinder pumps; and low pressure collection system with septic tank effluent pump (STEP) systems. Two of the potential alternatives, gravity sewers and STEP systems are ruled out for the Illahee/Oyehut planning area. STEP system effluent is are not allowed by the City of Ocean Shores (City) and gravity sewers, related gravity side sewers and lift station vaults are unfeasible, if not unworkable due to high groundwater conditions within the planning area. The dewatering cost, debris (logs) removal cost and uncertainty of construction conditions for deeper gravity lines in wet sand make the gravity alternative cost prohibitive. Therefore, the remaining two feasible alternatives, vacuum and low pressure sewer collection, are evaluated in this section. VACUUM SEWER COLLECTION SYSTEM ALTERNATIVE A vacuum sewer system generally consists of a central vacuum/pump station, vacuum collection mains and automated vacuum valves at the customer’s property to maintain a vacuum on the collection system. Vacuum sewer collection systems have been utilized by municipal sewage systems in the United States for the past 50 years. Gravity lines carry wastewater from the user to a vacuum valve pit. When approximately 10 gallons of wastewater collects in the pit sump, the vacuum valve opens and differential pressure from the vacuum in the sewer lines propels the contents into the vacuum main. Valve pits are typically shared between two to four homes. It is assumed that valve pits will be installed at a ratio of 2 connections per sump pit. The manufacturer does not recommend planning for more than 2 connections per sump pit because the difficult groundwater conditions in the area will make it difficult to extend long side sewer runs between house locations. Wastewater travels at 15 to 18 feet per second in the vacuum main to the vacuum station. The vacuum main is laid in a saw tooth fashion at 3 feet to 6 foot in depth. The saw tooth configuration allows for relatively shallow pipe bury and ensures adequate vacuum levels at the end of each line. Strategically located pressure sensors are typically placed at major sewer line junctions for trouble-shooting. The main vacuum sewer lines are installed at relatively shallow depths (from 3 to 6 feet). Sewer line installation can generally follow the lay of the land. However, the saw-tooth type installation requires tight tolerances on pipe installation (0.2% slope). The pipe material for vacuum mains is typically SDR 21 PVC pipe. “Reiber Style” gaskets need to be utilized for the pipe to be certified for vacuum use. Dewatering will be required for all main line and vacuum stations. More dewatering effort will be required as the pipe depth increases along the pipe run to the next saw tooth. The dewatering effort will increase for larger diameter pipe relative to smaller diameter pipe as well. Dewatering cost estimates are provided in the detailed project cost estimates in Appendix A.


At the vacuum station, vacuum pumps cycle on and off as needed to maintain a constant level of vacuum on the entire system. Wastewater enters the vacuum station and fills a collection tank. When the collection tank fills to a predetermined level, sewage pumps transfer the contents to the City collection system via a force main. The City utilizes AIRVAC, Inc. for vacuum collection system sizing and equipment. AIRVAC provided current sizing guidelines and cost data for the vacuum station and collection system for this report. Proposed schematic vacuum collection system layout is shown on Figure V-1. Approximately 72 “vacuum valves” and valve pits will be needed for the 143 current services. This alternative will require one centrally located vacuum station located near the intersection of Damon Road and Chickamin Road. Cost estimates include acquisition of a 30’ x 50’ property for the vacuum station and related odor control facilities. The vacuum station design criteria also includes an automatic standby electrical power generator to ensure the vacuum condition in the collection system is maintained during power outages. Vacuum Sewer Collection System Flow and Sizing AIRVAC uses proprietary spreadsheets to evaluate and size vacuum collection mains. Vacuum collection main sizing is based on the projected build out flow conditions established in Section II. AIRVAC also provided pipe sizing and vacuum station sizing for a scenario with an additional 200 ERUs (above Section II flows) for the Large Lots sub-area. The additional 200 ERUs would increase the pipe size along Chickamin Road from 8 inch to 10 inch diameter. AIRVAC also provided pipe sizing for an alternative that excludes all flow from the Large Lots sub-area. This information is used to determine pipe size differences for apportioning costs as discussed in Section VII of this report. The large lots do not require service in the immediate future, but this project needs to provide capacity for future flow from the Large Lots sub-area because there is no other feasible alternative for sewer service to this area. The 8 inch diameter alternative is utilized for comparison to the low pressure collection system alternative. There are some limitations associated with serving the Large Lots sub-area with a vacuum system. The most cost effective way for a vacuum system to serve larger hotel or commercial flows is with buffer tanks. AIRVAC design criteria limits the amount of flow that enters the vacuum system via buffer tanks to 25% of the total peak flow. The projected future Large Lots flow is 55% of the total flow. Based on the AIRVAC guidelines, the Illahee/Large Lots sub-areas can support up to 4 or 5 buffer tanks. If two or three of the allotted buffer tanks are utilized in the Illahee commercial areas, only two or three buffer tanks could be utilized in the Large Lot sub-area. This may increase development costs in both areas by requiring future development to install multiple smaller vacuum valve pits for development proposals with larger flows. AIRVAC indicates that the best alternative for very large flows is to serve them by other means (i.e. lift station(s) and force main) and not introduce the flow into the vacuum system at all.

Scale (in Feet)

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in A

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F

Illahee/Oyehut Planning Area

G

1,9

30’ 6" PVC

1,8

30’ 4" PVC

520’ 4" PVC

520’ 4" PVC

410’ 4" PVC

440’ 8" PVC

480’ 8" PVC

450’ 8" PVC

710’ 8" PVC

240’ 8" PVC

550’ 8" PVC

1,1

00’ 6" PVC

1,1

00’ 4" PVC

440’ 6" PVC

60’ CASING AND CARRIER PIPE

TRANSITION MH

EX. MH 1−15

1,020’ 6" PVC

520’ 4" PVC

VACUUM STATION

Vacuum Collection SystemPiping Schematic

Figure V-1

2"

3"4"

6"

8"Future

Pipe Legend


The basis for the sizing of the force main between the vacuum station and the discharge location at Manhole (MH) 1-15 is provided in the discussion of the low pressure collection system alternative below. Flow metering will be provided at the vacuum station discharge. Easements for vacuum valve pits may be needed for the Oyehut area due to limited right of way. Vacuum Sewer Collection System Cost The total project cost for the vacuum sewer collection system includes “collection system construction cost” and “direct service costs”. The collection system construction cost includes materials and labor for construction of the vacuum station and collection system piping up to the customer’s property, property acquisition for the vacuum station, a 20% construction contingency, 8.4% sales tax, and a 30% allowance for administration, surveying, design, construction management, and construction inspection. The easements for vacuum valves are considered to be a mutual benefit (i.e. not a project cost) and will be required as a condition of service. The direct service costs include system development charges, abandoning of existing septic tanks, installing vacuum valves and installing side sewer laterals between the house and the vacuum valve at each connection. The total of the collection system cost and direct service costs for the vacuum collection system is estimated to be $3.98 Million. For comparison, in 2010 the City estimated that the cost for a similar vacuum sewer system for the Illahee/Oyehut planning area would be $3.05 Million for the collection system and 0.59 Million for direct costs (total cost of $3.64 Million). A future vacuum sewer extension for the Large Lots sub area based on estimated flows for the build out condition is estimated to be about $400,000, not including direct service costs. A separate force main from Damon Road to avoid the buffer tank limitations discussed above is estimated to be about $500,000, not including direct service costs. The additional project costs required to upsize the vacuum collection system piping and vacuum station to be capable of serving future flows from the Large Lots sub-areas (415 ERUs) is $157,000. Expected O&M includes maintaining the sewer line, vacuum valve pits, vacuum/pump station, materials, electricity and administrative costs. The annual average estimated O&M cost in 2013 dollars is approximately $30,028. Long term O&M, including rehabilitation and replacement of equipment is addressed in the cost-effectiveness evaluation in Section VI herein. LOW PRESSURE SEWER COLLECTION SYSTEM ALTERNATIVE The low pressure sewer system generally consists of individual grinder pumps and low pressure sewer collection mains. Wastewater flows by gravity from buildings to individual or shared grinder pump vaults located on private property. Solids in the raw wastewater are ground up and pumped from the sump through a service line (typically 1 1/4-inch diameter) to a small diameter pressure main (pipe diameters ranging from 1 1/2 to 6 inch). Low pressure sewer collection systems utilizing individual and shared grinder pumps have been utilized by municipal sewage systems for the past 50 years. Low pressure collection systems are typically arranged as zone networks without loops. Depending on topography, size of the system and planned rate of build out, appurtenances


may include valve boxes, flushing arrangements, air release valves at significant high points, check valves and full-ported stops at the junction of each house connection with the low pressure sewer main. The individual or shared grinder pump is actuated when the depth of the sewage in the grinder pump vault reaches a set “turn-on” level, and pumping continues until the “turn off” level is reached. The maximum normal operating pressure for typical grinder pumps currently utilized in County low pressure collection systems in other areas is 80 psi. Occasionally during typical operating conditions, there will be short periods when collection system pressure will exceed the maximum normal operating pressure. The higher pressure events can result from a variety of causes including solids buildup (obstructions) or air bubbles. Deposits of solids or air accumulation will be purged from the line as pressure increases and as the reduced cross section increases velocity to provide the scouring action needed to correct build-up conditions. These higher–than–expected pressure conditions are transitory occurrences and do not affect operation and maintenance as long as properly rated pumps and piping are installed. Typical individual grinder pumps utilized by the County in Pacific Beach can operate at 50 percent above rated pressure for at least 5 minutes without excessive temperature rise. Based on extensive pressure testing and monitoring results from the County’s Pacific Beach/Moclips low pressure sewer collection system, it is rare for this type of condition to last as long as one minute. Grinder pump stations are also designed to provide holding capacity for wastewater storage during most electrical power outages. The County currently requires installation of grinder vaults with 238 gallons of storage per resident, which will provide over 2 days of capacity under average flow conditions identified in Section II of this report. When power has been restored after a power outage, it is likely that many of the pumps in the system will try to operate simultaneously. Under these conditions, the dynamic head loss component of the total head will rise significantly. A number of pumps in the system would see a total back pressure high enough to cause the thermal overload protectors to automatically trip after several minutes to prevent damage to the pumps or the collection system. While these pumps are offline, other pumps in the system would be able to empty their tanks. After one to two minutes, the group that tripped off on thermal overload would cool and restart. The system back pressure would then have been reduced and the group that originally tripped out would be able to pump down normally. This process repeats itself automatically under the influence of each unit’s own thermal protector, reliably restoring the system to normal operation. Experience in the Pacific Beach sewer system confirms this operational scenario. Only on very limited occasion have the circuit breakers tripped to require a manual reset. The need for manual reset of pumps is typically only associated with areas where poor construction has led to Infiltration and Inflow (I/I) entering the system. The recommended pipe material for low pressure mains in this case is SDR 11 HDPE. A higher SDR rating can be utilized, but the SDR 11 pipe is chosen for its durability relative to higher SDR rated pipe. The HDPE pipe can be fused together with service tees and valves outside the trench and installed at a relatively shallow depth (30 inches to 36 inches) in most project area. The smaller diameter pipe will not require dewatering other than portable trench line pumps in most locations for summer construction. It is anticipated that well points will be required for a majority of the 4


inch and all of the 6 inch force main. Isolations valves will be installed at tees and every 2,000 feet on main line runs. Plug valves with geared operators will be used for 3 inch and lager piping and PVC or HDPE ball valves will be used for 2 inch and smaller piping. Dewatering efforts are substantially reduced for this alternative since a majority of the pipe and fittings can be fused together above ground instead of within the trench. A shared electrical service on small grids serving from 3 to 6 pumping units will be utilized for multiple pumps in lieu of power supply from private residences. An electrical panel for each grinder pump is installed on the side of the customer’s building. Hour meters are installed in pump panels to keep track of grinder pump operating time for O&M purposes. Metering of the flow from the entire collection system will be provided prior to discharge at the City Manhole. Low Pressure Sewer Collection System Flow and Sizing Flow for low pressure sewer collection system hydraulic modeling is determined using a grinder pump methodology to supplement the Washington State Department of Ecology (Ecology) Orange Book ERU methodology presented in Section II of this report. The grinder pump methodology utilizes published values for probable peak discharge from multiple grinder pumps. Generally, the grinder pump methodology is more conservative than the Orange Book methodology for lower levels of development density. The grinder pump methodology is also more practical for evaluating flow for exclusive use of grinder pumps on low pressure piping systems. The typical grinder pump utilized by the County has a capacity of about 12 gpm at normal discharge pressure. For most development within the coastal areas, 1 grinder pump is adequate for every two residential units. The County utilizes pump chambers that allow for the addition of a second pump if needed. Larger duplex grinder stations, consisting of two 2 horsepower (HP) pumps in a 5 foot diameter vault, are utilized for larger development clusters. These duplex stations with larger grinder pumps can also be utilized for commercial development as needed. The maximum capacity for the duplex stations is about 50 gpm (25 gpm per pump) at the expected typical discharge pressure. Table V-1 presents the estimated grinder pump flows for the Oyehut sub-area portion of the collection system.

Table V-1 Grinder Pump Flow Projections for the Oyehut Sub-Area

Model Junction ERUs per Junction

Grinder Pumps per Junction

Simultaneous Pump Operation

Local Peak Junction Flow (gpm)

Cumulative Pumps


Cumulative Model Flow (gpm)

Oyehut 6 (O6) 8 4 3 36 4 3 36 Oyehut 5 (O5) 3 2 3 36 6 3 36 Oyehut 4 (O4) 3 2 3 36 8 3 36 Oyehut 3 (O3) 14 7 3 36 15 4 48 Oyehut 2 (O2) 36 18 3 36 33 6 72 Oyehut 1 (O1) 8 4 5 60 37 6 72 Damon Road 3 (DR3) 13 7 4 48 44 6 72 Damon Road 2 (DR2) 30 15 5 60 59 7 84 Total 115 59 7 84

Notes: Local Peak Junction and Cumulative peak flow are based on published probability data (E-One).


The estimated cumulative peak hourly flow of 84 gpm for the Oyehut sub-area based on the grinder pump methodology is more conservative than the 32 gpm peak hourly build out sewage flow projected in Section II. Table V-2 presents the estimated grinder pump flows for the Illahee and Large Lot sub-areas of the collection system.

Table V-2 Grinder Pump Flow Projections for Illahee and Large Lot Sub-Areas

Model Junction ERUs per Junction

Grinder Pumps per Junction


Local Peak Junction Flow (gpm)

Cumulative Pumps


Cumulative Model Flow (gpm)

Large Lots E-G (L5) 15 8 3 36 8 3 36 Large Lots D (L4) 100 50 7 84 58 7 84 Large Lots C (L3) 100 50 7 84 108 8 96 Large Lots B (L2) 100 50 7 84 158 10 120 Large Lots A (L1) 100 50 7 84 208 11 132 Illahee 10 (I10) 7 4 3 36 212 11 132 Illahee 4 (I4) 5 3 2 24 215 12 144 Illahee 9 (I9) 8 4 3 36 219 12 144 Illahee 3 (I3) 11 6 3 36 225 12 144 Illahee 8 (I8) 9 5 3 36 230 12 144 Illahee 2 (I2) 15 8 3 36 238 12 144 Illahee 7 (I7) 8 4 3 36 242 12 144 Illahee 1 (I1) 60 30 6 72 272 13 156 Damon Road 1 (DR1) 100 50 7 84 322 15 180 Total 638 319 14 168

Notes: Local Peak Junction and Cumulative peak flow are based on published probability data (E-One).

The estimated cumulative peak hourly flow of 180 gpm for the Illahee and Large Lot sub-areas is just slightly more conservative than the 175 gpm peak hourly build out projected sewage flow based on the Ecology Orange Book methodology in Section II. Grinder pumps are assigned to Large Lots and commercial zoned areas at one grinder pump per two ERUs. This is more conservative than estimating these flows on a cluster basis. The overall combined estimated grinder pump peak hourly flow of 264 gpm (84 + 180) for the entire planning area is also more conservative than the projected build out flow of 207 gpm presented in Section II. The force main collection system was modeled using EPANET2 developed by EPA's Water Supply and Water Resources Division. EPANET2 is open source software developed to primarily model water distribution piping systems. Based on EPANET2 documentation, the model can be adapted to a pressure sewer system by utilizing tanks for wet wells and negative demands at nodes to simulate individual positive displacement type grinder pumps. Model calibration is not necessary in this case due to the relative simplicity of the model and known pipe conditions. Calibration of


previous modeling by Gibbs & Olson conducted for Grays Harbor County in Pacific Beach/Moclips grinder pump collection system indicated that the published data by E-One regarding simultaneous grinder pump operation are reliable for coastal communities during peak summer conditions. Manhole discharge for this modeling is simulated with a large tank discharge condition. The large tank condition creates a stable discharge head condition that approximates the conditions at the proposed discharge manhole. Existing construction drawings and general mapping were utilized to develop a schematic collection system model. Hydraulic model maps are provided in Appendix B. A Hazen-Williams roughness coefficient of 140 is utilized for all piping. This roughness coefficient is lower than published values for HDPE (150), but is realistic for a sewage force main that may have solids build up and is also somewhat conservative with regard to modeling future conditions. Pump curves are not required in the model because positive displacement type individual grinder pump discharge volume does not change significantly for varying head conditions. The primary factors in selecting the proper force main size are velocity and headloss. A minimum self-scouring velocity of 2 feet per second (fps) should be maintained in force mains unless facilities are provided for routine cleaning. Velocity should not exceed 8 fps to 10 fps. The higher range of velocity can cause pipe scouring and create adverse pumping conditions for longer forcemains. Optimum velocity for reducing maintenance costs and preventing accumulation of solids is in the range between 3.5 fps to 5 fps. An attempt should be made to provide the higher range of optimum velocity where forcemain profiles exhibit multiple high points and low points and where intermittent pumping is expected. Based on the types of grinder pumps that are and could be utilized, the maximum design pressure for the force main in areas with grinder pump discharges is 80 psi. The recommended collection system sizing is shown on Figure V-2. Velocity for the peak hourly flow conditions is above 2 fps for all main lines. The 2-inch pipe branches in Illahee have less than 2 fps at cumulative model flows, but velocity will approach 4 fps intermittently for the local area peak hourly flows. Maximum pressure under the modeled condition for build out is 40 psi at the ends of the system. Various model runs were completed to determine the effects of local peak flows and the limiting hydraulic conditions. The Oyehut piping is ultimately limited by the cumulative pressure at the north end of the Oyehut piping and the Illahee/Large Lot piping is ultimately limited by velocity in the 4 inch pipe just north of Damon Road. The additional model runs also indicate that there is some flexibility for the low pressure collection systems to accommodate development patterns that may vary from the growth scenarios discussed in Section II.

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2,350’ 3" HDPE

1,400’ 2" HDPE

300’ 2" & 220’ 1.5" HDPE

350’ 2" & 170’ 1.5" HDPE

350’ 2" & 170’ 1.5" HDPE

230’ 2" & 180’ 1.5" HDPE

440’ 4" HDPE

480’ 4" HDPE

450’ 4" HDPE

450’ 2" HDPE

730’ 4" HDPE

500’ 2" HDPE

340’ 4" HDPE

840’ 4" HDPE

550’ 3" HDPE

550’ 2" HDPE

440’ 6" HDPE 60’ CASING AND

CARRIER PIPE

TRANSITION MH

EX. MH 1−15

400’ 3" HDPE620’ 4" HDPE

Illahee/Oyehut

Planning Area

<3"3"

4"

6"8"

Future

Pipe Legend

Low Pressure Collection SystemPiping Schematic

Figure V-2


Model runs were also conducted to evaluate the effects of the initial case of having no development within the Large Lots sub-area. In this case, the pipe size for the Illahee sub area should be reduced from 4 inch diameter to 2 inch diameter north of Moxt Street. The velocity within the 4 inch piping from Ikt Street to Moxt Street also drops to 1.5 fps under this scenario. The optimum size for this portion of the piping in Chickamin Road between Ikt Street and Moxt Street is 3 inch, however, the 4 inch size is recommended to provide for future Large Lots sub-area flows. This is a relatively short section of pipe (480 feet) that can be flushed or pigged periodically to minimize solids build-up. The velocity for the 6 inch piping south of Damon Road is likely optimally sized since velocity is greater than 2 fps with and without development in the Large Lots sub area. Low Pressure Sewer Collection System Cost The total project cost for the low pressure sewer collection system includes “collection system construction cost”, “direct service costs” and ULID and funding administrative costs. The collection system construction cost includes materials and labor for construction of the collection system piping up to the customer’s property, a 20% construction contingency, 8.4% sales tax, and a 30% allowance for administration, surveying, design, construction management, and construction inspection. The easements for grinder pumps and electrical service are considered to be a mutual benefit (i.e. not a project cost) and will be required as a condition of service. The direct service costs include system development charges, abandoning of existing septic tanks, installing grinder pumps and installing side sewer laterals between the house and the grinder pump vault at each connection. The total of the collection system cost and direct service costs for the low pressure collection system is estimated to be $2.67 Million. A future low pressure sewer extension (from Moxt Street) for the Large Lots sub area based on estimated flows for the build out condition is estimated to be about $300,000, not including direct service costs. The additional project costs required to upsize the low pressure collection system piping to be capable of serving future flows from the Large Lots sub-area is $18,000. Table V-3 provides a summary of total costs for each alternative.

Table V-3 Capital Cost Summary Vacuum Low Pressure Collection System Construction $ 2,647,606 $ 1,216,075 Direct Service Cost $ 1,095,350 $ 1,246,061 ULID Expenses $ 160,000 $ 160,000 Financing Cost and Administration $ 74,859 $ 49,243 Total $ 3,977,816 $ 2,671,379

Expected O&M includes maintaining the sewer line, grinder pumps, materials, electricity and administrative costs. The annual estimated O&M cost in 2013 dollars is approximately $33,440. Long term O&M, including rehabilitation and replacement of equipment is addressed in the cost-


effectiveness evaluation in Section VI herein. Table V-4 provides a summary of annual O&M cost for each alternative.

Table V-4 O&M Cost Summary Vacuum Low Pressure Annual Labor and Electricity Cost $23,138 $14,900 Average Annual Equipment Replacement Cost $6,891 $18,540 Total $30,028 $33,440

OPERATING COSTS AND RATES Six year operating budgets for each alternative are included with the project cost estimates in Appendix A. The following assumptions are utilized as a basis for identifying budget constraints and future revenue requirements. − Residential and commercial base rates will be in accordance with current City municipal code − Commercial commodity charge will be in accordance with current City municipal code − All rates for the planning area will be subject to a 1.75 outside City Limit multiplier. − Current City rates are assumed to be a good indication of the actual cost associated with

treatment and existing City collection system O&M costs. − Previous and future ULID formation cost are included in the total collection system

construction cost. − Financing administration and related fees is estimated to be 2% of total construction costs. − The conservative customer growth rate is 1.0% annually − Annual revenue increases are estimated at 2.0% annually − Annual City Sewer Rate Inflation is estimated at 2.5% annually − Inflation of O&M costs is estimated at 2.5% Annually − A portion of rates will be collected for capital reserves proportional to build out conditions. − City System Development Charges ($1,800/ERU) are included in direct service costs within

the total construction cost estimates. − Capital reserve goals to be based on amortized system construction cost. Short term

replacement costs are amortized over 15 years and long term replacement cost is amortized over 75 years. Projected build out ERUs are used as the prorated share for current customer investment into capital reserves.

The above assumptions are provided to assist in creating representative budgets that are conservative with regard to future rate policy. These budget numbers represent a basic outline of the expected costs and circumstances that will drive rate decisions. It should be acknowledged that rate decisions are ultimately made by the City Council and County Commission.


The City has indicated that they would not own or operate a low pressure sewer collection system. Similarly, the County has indicated that the City would likely be best suited to operate a vacuum sewer system if a vacuum system is selected as the most feasible for the Illahee/Oyehut area. Therefore, the vacuum sewer budget considers City operation and the low pressure alternative budget only considers ownership and operation by the County. Table V-5 presents the expected average user rates based on the above budget assumptions.

Table V-5 Estimated Average Monthly User Rates Vacuum Low Pressure Residential $60 $ 54 Commercial (per ERU) $99 $ 93

The vacuum sewer collection system has a lower annualized O&M cost (combined pump replacement reserve and labor) by about $3,000 per year, but the labor portion for vacuum collection system O&M and administration (which has a greater effect on annual rates) is about

$6,000 per year higher. The anticipated residential rate for both alternatives is at the higher end of outside City rates for other communities. Rates may also be impacted by funding program requirements. The applicable funding programs discussed in Section VII of this report require a debt service reserve equal to 10% of the annual loan payment through the term of the loan. This debt service reserve, if required, will increase rates by about $10 per month for both sewer collection alternatives. The cost of previous design work does not apply to this project. Review of the previous vacuum system design work is not part of the scope of work for this project and previous vacuum sewer design work was not provided by the City. The City has indicated that the previous vacuum system design had a different vacuum station location, which will change the pipe sizes and layout. The design is also 10 years old, which would also create professional liability concerns if utilized.

Grays Harbor County VI - 1 Section VI - Selection of an Alternative Illahee/Oyehut Sewer Collection System April 2013 Engineering Report Gibbs & Olson, Inc.

SECTION VI SELECTION OF AN ALTERNATIVE

NET PRESENT WORTH The basic principles of using “net present worth” for selection of an alternative in this report are derived from U.S. Office of Management and Budget (OMB) Circular A-94. Determining the “net present worth” is discounting of a future cash flow to its present value. Economic analysis principles typically favor the value of today’s money more than future money. In an economic analysis of net present worth, a discount rate is used to work out the present value of a project, purchase or investment. The use of a discount rate allows the comparison of benefits and costs of an investment for a project that occur at different point of time. The present value costs in this report are based on the “real” federal discount rate of 1.1% from Appendix C of OMB Circular A-94. This specific analysis in this report represents more of a “Cost-Effectiveness Analysis”. A cost-effective analysis of the life cycle cost is used to compare competing alternatives. The most cost-effective alternative has the lowest costs expressed in present value terms for a given amount of benefits. OMB Circular A-94 indicates that a cost-effectiveness analysis is appropriate whenever it is unnecessary or impractical to consider the dollar value of the benefits provided by the alternatives under consideration. In this case, it is both unnecessary and impractical given the benefits to the environment and economy that cannot be easily measured and the overall need for this project regardless of the benefit cost outcome. Table VI-1 provides a summary of the results of the Cost-Effectiveness Analysis. The capital and O&M cost estimates utilized for the Cost-Effectiveness Analysis are provided in Appendix A. Detailed net present worth evaluation spreadsheets are provided in Appendix C.

Table VI-1 Net Present Value of Collection System Alternatives Analysis Period Collection System Alternative 10-Year 20-Year 30-Year Net Present Value - Low Pressure Sewer Collection -$2,709,721 -$4,507,748 -$5,029,280

Net Present Value - Vacuum Sewer Collection -$3,762,917 -$6,038,960 -$6,535,826

Difference (i.e., Cost-Effectiveness) $1,053,196 $1,531,212 $1,506,547

Notes: 1.1% “real” federal discount rate (30 years) 2.5% Annual O&M Inflation 1.5% Customer Growth 4.5% Interest rate for 20 year debt service on total costs Only net life-cycle “costs” are evaluated

The analysis indicates that the low pressure collection system alternative is significantly more cost effective than the vacuum sewer collection alternative. A thirty year period was utilized to provide a good estimate of the impacts of equipment rehabilitation and replacement on net present value

Grays Harbor County VI - 2 Section VI - Selection of an Alternative Illahee/Oyehut Sewer Collection System April 2013 Engineering Report Gibbs & Olson, Inc.

for each alternative. The results indicate that there would be no significant influence on the outcome by extending the time period past 30-years. In addition, a sensitivity analysis indicates that significant changes in the discount rate, CPI (O&M inflation) and/or customer growth does not influence the outcome of the analysis. RECOMMENDED PROJECT A low pressure sewer collection system is the recommended alternative for the Illahee/Oyehut planning area. The low pressure sewer collection alternative has the lowest capital cost, similar annual operating cost and highest net present value. The low pressure collection system alternative is also more feasible with regard to adding flow from the Large Lots area in the future. This project will improve the environment by providing a means to remove untreated or partially treated sewage from the ground, increase protection of public health by reducing environmental contaminates and protecting shellfish and allow for property owners to develop property in a responsible and cost effective manner.

Grays Harbor County VII - 1 Section VII - Proposed Project Illahee/Oyehut Sewer Collection April 2013 Engineering Report Gibbs & Olson, Inc.

SECTION VII PROPOSED PROJECT

A low pressure sewer collection system is the recommended alternative for providing centralized sewer service to the Illahee/Oyehut planning area. The low pressure sewer collection alternative has the lowest capital cost, lowest annual operating cost and highest net present value of the feasible alternatives that were considered. The total of the collection system cost and direct service costs for the low pressure collection system is estimated to be $2.67 Million. PROJECT DESCRIPTION The low pressure sewer collection system will be implemented within the Illahee and Oyehut sub-areas only. Implementation of a collection system for the Large Lots sub-area is not practical at this time since there is no existing development north of the Illahee sub-area and no specific development proposals to indicate where sewer lines should be installed. Collection system mains will be upsized where practical to accommodate future flows from Large Lots sub-areas. Future service to Large Lots will be completed through developer extensions by the property owners. However, the existing single family residence at Large Lot F north of Oyehut will be served off of the Oyehut branch of the proposed collection system. A schematic of the proposed low pressure sewer collection system piping is shown on Figure VII-1. The proposed collection system consists of two pipe branches with one branch serving the Illahee sub-area and the other branch serving the Oyehut sub-area. The branches come together at the intersection of Damon Road and Chickamin Road. An easement may be needed along the north side of Damon Road to allow for proper separation between the existing water main and the new sewer main. An easement along the Oyehut Corporation property can also reduce some costs associated with installing the pipe within the WSDOT Highway 115 right-of-way that ends at Point Brown Avenue. The recommended pipe material for low pressure mains for this project is SDR 11 HDPE. SDR 11 HDPE is rated for a working pressure of 160 psi which is well above the 80 psi maximum normal operating pressure for typical grinder pumps. The SDR 11 HDPE pipe can be fused together with service tees and valves outside the trench and installed at a relatively shallow depth (30 inches to 36 inches) in most project areas. The minimum open trench needed for laying 3 inch and smaller continuous SDR 11 HDPE pipe is 15 feet (PPI Handbook of Polyethylene Pipe). The smaller diameter pipe will not require dewatering other than portable trench line pumps in most locations for summer construction. However, some additional localized dewatering effort may be required during higher tidal periods. It is anticipated that well points will be required for dewatering a majority of the 4 inch and all of the 6 inch force main trenches. Lean concrete will be placed in-line with all low pressure collection system pipe every 20 feet to prevent pipe uplift in locations where groundwater is expected to be within 2 feet of the surface.

Scale (in Feet)

D amon Rd.

Hig

h

Sch ool

D amon Rd.

Ch

ick

am

in A

ve.

Oy

eh

ut R

d.

F

2,3

50

’ 3

" H

DP

E

1,4

00

’ 2

" H

DP

E

300’ 2" & 220’ 1.5" HDPE

350’ 2" & 170’ 1.5" HDPE

350’ 2" & 170’ 1.5" HDPE

230’ 2" & 180’ 1.5" HDPE

44

0’

4"

HD

PE

48

0’

4"

HD

PE

45

0’

2"

HD

PE

50

0’

2"

HD

PE

44

0’

6"

HD

PE 60’ CASING AND

CARRIER PIPE

TRA NSITION MH

EX. MH 1−15

400’ 3" HDPE620’ 4" HDPE

Illahee/Oyehut

Planning Area

<3"

3"

4"6"

8"

Pipe Legend

Low Pressure Collection SystemProject Schematic

Figure VII- 1


Isolation valves will be installed at tees and at every 2,000 feet on main line runs. Plug valves with geared operators will be used for 3 inch and lager piping and PVC or HDPE ball valves will be used for 2 inch and smaller piping. It is anticipated that approximately 10 isolation valves, 10 clean-outs and 2 air-release valve stations will be needed. A steel bore casing will have to be installed under Damon road to extend the low pressure collection force main south along Short Cuddy Avenue to the discharge location at Ocean Shores Blvd. The proposed discharge location is manhole MH 1-15. The flow capacity at MH 1-15 is 680,000 gpd based on the City’s 2008 Facility Plan. The capacity of the City collection system exceeds 1 MGD downstream of MH 1-15. The Ocean Shores Blvd gravity system discharges to MH 1-2 in Point Brown Avenue and then continues to the City’s Pump Station No. 1. The current development just upstream and downstream of MH 1-15 is in the range of 300 to 400 ERUs. The anticipated peak hourly flows from the current development in the vicinity of MH 1-15 is likely in the range of 100,000 to 200,000 gpd. The combined peak hourly flow from current development and build out conditions in the Illahee/Oyehut planning area is likely within a range of 300,000 gpd to 400,000 gpd. The available capacity in the Ocean Shores Blvd gravity system is significantly greater than the expected peak hourly flows. During the initial stages of the project, low flow conditions in the planning area may create septic conditions in the downstream low pressure collection system piping. The new piping material will be able to handle the potentially septic conditions, but the City’s existing manhole MH 1-15 and downstream concrete piping may be subjected to corrosion caused by hydrogen sulfide. To address this issue, a new discharge manhole will be constructed 40 feet upstream of MH 1-15. The proposed discharge manhole will minimize impacts to the City’s existing manhole and concrete gravity piping by introducing air into the potentially septic flow and combining the flow with other flow from upstream. The discharge manhole will be designed with protective coating, aeration column and internal odor control inserts. A flow meter vault with magnetic flow meter will be installed upstream of the discharge manhole. The flow meter will be battery operated unless a convenient cost-effective power source can be installed. One grinder pump will be installed for every two residential services. The shared grinder pump vault will accommodate an additional pump if needed to address higher flow conditions at specific locations. A 1 1/2-inch diameter pump discharge line will be installed from each vault to the pressure main. A check valve and full-ported ball valve stop will be incorporated into each discharge line. The grinder pump vaults will be installed with concrete collars at the base of the vault to prevent the vault from floating out of the ground. The concrete collars will typically be installed on vaults prior to burial. The top of the grinder pump vaults will be set at 1 foot above the known local high water elevation. Small electrical service grids will be installed along the property frontage to serve from 3 to 6 pumping units per grid. This will avoid costly upgrades to electrical wiring and electrical panels within the many older houses in the planning area. An electrical panel with an hour meter and


alarm light will be installed for each grinder pump on the side of the customer’s building. The plumbing within the existing building will have to be modified to divert the building sewage flow from the existing septic tanks to the new grinder pump vaults located on private property. Septic tanks will then have to be abandoned per County Environmental Health Standards. Expected Operation and Maintenance (O&M) includes maintaining the sewer line, repairing and replacing grinder pumps, valves and electrical panels and administrative activities related to billing and management. O&M activities on the collection system will be very low initially and are expected to eventually increase to 4 to 5 man-hours per week on average.

PROJECT COST SUMMARY The total project cost for the low pressure sewer collection system includes “collection system construction cost” and “direct service costs”. The collection system construction cost includes materials and labor for construction of the collection system piping up to the customer’s property, a 20% construction contingency, 8.4% sales tax, and a 30% allowance for administration, surveying, design, construction management, and construction inspection. The easements for grinder pumps and electrical service are considered to be a mutual benefit (i.e. not a project cost) and will be required as a condition of service. The direct service costs include system development charges, abandoning of existing septic tanks, installing grinder pumps and installing side sewer laterals between the house and the grinder pump vault at each connection. A break down of total project costs is shown in Table VII-1.

Table VII-1 Project Cost Summary Description Cost Collection System Construction Cost $1,216,075 Direct Service Construction Cost $1,246,061 ULID Expenses $160,000 Funding Admin and Environmental $49,243 Total $2,671,379

The additional project costs required to upsize the low pressure collection system piping to be capable of serving future flows from the Large Lots sub-area is $18,000. The County will recover these costs through a surcharge to the system development charge that will be specific to the Large Lots sub-areas. This charge will be added to other applicable charges and development fees. New connections in the Illahee and Large Lots sub areas will also have to pay City system development charges and County inspection and connection fees at the time of connection. The amount for County connection fees will be determined after initial project implementation. PROJECT FINANCING The County will likely submit funding applications to Washington State Department of Ecology (Ecology) and/or the U.S. Department of Agriculture, Rural Development (RD) Rural Utility Service (RUS). The following is a discussion of the highlights of each program.


Ecology Funding Programs The Ecology Water Quality Program administers two funding programs that provide grants and low-interest loans to projects that improve and protect water quality. The funding programs are the Centennial Fund, which provides grants and the State Revolving Fund, which provides low-interest loans only. Ecology has streamlined the process for both programs by combining the applications. However, they continue to follow a three step process in which Step I is the planning process, Step II is the design process and Step III is the construction process. Ecology will not accept a funding application for Step II until after they have approved the Step I planning documents. The Centennial fund is intended to aid communities where sewer improvements would impose a financial hardship upon low and moderate income rate payers. A financial hardship is defined by Ecology to exist if the monthly sewer rate is proposed to be at, or above 2 percent of the median household income (MHI). Depending upon the degree of financial burden, Ecology may offer grants for 50%, 75% or even 100% of the project cost up to five million dollars. Grant funds are only available for construction and not for facilities planning, sewer development charges or design. The State Revolving Fund (SRF) provides low-cost financing or refinancing to local governments for projects that improve and protect the state’s water quality. Projects may include publicly-owned wastewater treatment facilities, non-point source pollution control projects, and comprehensive estuary conservation and management programs. Loans may be provided for up to 100 percent of the total eligible project cost. Sources of money for this program include federal and state funds. Since federal funds are provided through the U.S. Environmental Protection Agency (EPA), projects must comply with federal requirements. This includes completion of an environmental assessment as per the National Environmental Policy Act (NEPA). Currently the non-hardship interest rate for the State Revolving Fund program is 1.4 percent for up to a 5-year term and 2.8 percent from beyond five years to 20-year loans. These rates are based on 60% of the market rate. There are reduced interest rates available for hardship communities ranging from 40% of the market rate down to 0% interest for a 20-year loan. The application period for grant and loan funding through the Combined Funding Process opens each year on September 1, and closes on the first Friday in November. Funding application, review and approval process can optimistically take 1 year. The process begins with submittal of the application and ends with Agreement Development and funds dispersion by September to October of the following year. Each project is assigned priority-rating points by Ecology personnel and prioritized. Those projects receiving the highest priority points and falling within the available budget receive a low interest loan or, infrequently, hardship grant funding. Applicants with an enforcement action (from Ecology and/or EPA) and/or a public health emergency or severe public health hazard receive the


highest priority. In recent years, Ecology has awarded additional points to applicants utilizing the local-prioritization process through their local watershed-planning group. To be eligible to apply for funding under the Centennial and Revolving Fund programs, the County must have an Ecology approved Facility Plan and all environmental review processes complete prior to the application submittal deadline. Design costs are not eligible for grant funding, but are eligible for State Revolving loans. The Centennial grant program will fund existing capacity plus an allowance of 10 percent for growth. The State Revolving loan program will fund capacity for a 20-year period. For both programs, projects must begin within 16 months of the publication of the final offer list, and be completed within five years.

Rural Development Funding RUS (formerly known as Farmers Home Administration, FmHA and RDA) primarily provides loans to rural communities for a variety of projects at lower interest rates than can be obtained through the sale of revenue bonds. Grant funding is determined on a case-by-case basis, generally after all other funding sources are in place. The threshold determination for qualifying for a grant is tied into the amount that residential customers are paying for debt service, the amount of grant money obtained from all funding sources, and the amount other communities with similar sewage facilities are paying for their service. RUS accepts applications throughout the year and funds projects on a first come, first serve basis up to their annual budget. Since the federal fiscal year begins in October, there is generally more money available for loans at this time. RUS will work with a community to help put a funding package together. However, they prefer to see other funding sources in place prior to making their commitment. Currently, 20-year revenue bonds sold through RUS have a 3.125 percent interest rate and require a 10 percent coverage factor. However, this rate is approximate and can fluctuate throughout the year. RUS funding scenarios in this report assume a more conservative interest rate of 4.5%. Community Development Block Grant Program The County may also pursue a grant from the Community Development Block Grant (CDBG) program. However, CDBG funding has a very high administration cost, can have a high application cost and is very competitive. Consideration will be made to at least evaluate the potential for using CDBG funding for direct side sewer costs on low income properties. Utility Local Improvement District (ULID) Utility Local Improvement Districts (ULIDs) are special assessment districts. These districts are formed as a means of assisting benefiting properties in the financing of and payment for needed capital improvements. These special assessment districts are formed to permit the improvements to be financed and paid for over a period of time (not to exceed 30 years) through assessments on the


benefiting properties. The difference between ULIDs and LIDs is that, in addition to the assessment on the benefiting properties, utility revenues can be pledged to the repayment of the ULID debt. ULIDs do not have to create hardships or displace residents. Deferral options are available for low income and senior citizens. Assessments can be deferred indefinitely for qualified senior citizens (RCW 84.38). A deferral of up to four years for economically disadvantaged property owners is also possible (RCW 35.43.250 and 35.54.100). In both cases, the deferred assessment does not go away, but becomes a lien against the property. Additional emphasis will be placed on the potential use of CDBG grants to pay the direct cost for connections if it becomes apparent that there are a significant number of low income residents in the new service area. In addition to the cost of the improvements, bond sales involve bond counsel, underwriters and other expenses. All of these expenditures must be added to the project costs that LID participants must assume. The estimated ULID formation administrative cost is 6% of the collection system construction cost. Table VII-2 identifies projected assessment costs for different property types within the Illahee and Oyehut sub-areas.

Table VII-2 Estimated Property Assessments Property Type Collection System Cost Direct Cost Total Average Oyehut Space $6,403 $8,826 $15,229 Illahee Lot, 10,000 SF with Service $4,616 $8,826 $13,442 Illahee Lot, 10,000 SF without Service $4,616 $0 $4,616 Illahee Lot, 20,000 SF with Service $9,231 $8,826 $18,057 Illahee Lot, 20,000 SF without Service $9,231 $0 $9,231

Cost Includes: $ 60,000 New ULID Expenses on Collection System

2% Financing Expenses added to Collection System Cost 13,540 sf, average for Oyehut Spaces (developable areas)

State statutes specify that the assessment per parcel must not exceed the special benefit of the improvement to that parcel, which is defined as the difference between the fair market value of the property before and after the local improvement project. The County will likely simplify the assessments based on a mathematical formula and check a few strategic parcels with a limited appraisal for the low pressure collection system ULID process. In January 2010 at a Town Hall Meeting, the former City Public Works Director reported that the estimated special benefits were $15,000 for smaller lot sizes and Oyehut spaces. If that is still the case, the special benefits will likely exceed the assessment cost. However, if special benefits are lower, grant funding or a revenue bond will be needed to make up the difference. Special benefits relative to the low pressure collection system and the current real estate market will have to be evaluated by the County during the ULID process.

If the ULID process is completed, lot owners would be offered various payment options on the assessments. The interest rates for the annual payment option would likely be in the range of 1%


to 2% above the interest rate for the construction funds to cover administrative expenses. Lot owners could pay off the entire assessment at one time, refinance the assessment under better private loan terms or increase payments to avoid paying some of the interest over the loan term. Table VII-3 provides an example of monthly and annual payments on the projected assessments discussed above.

Table VII-3 Estimated Annual Payments for Assessments Average Oyehut Space $1,274 Illahee Lot, 10,000 SF with Service $1,125 Illahee Lot, 10,000 SF without Service $386 Illahee Lot, 20,000 SF with Service $1,511 Illahee Lot, 20,000 SF without Service $772

Assumes Payback over 20 Years @ 5.5% (Example)

OPERATING COSTS AND RATES A six year operating budget for the low pressure sewer collection system is included with the project cost estimates in Appendix A. The following assumptions are utilized as a basis for identifying budget constraints and future revenue requirements. − Rates will need to cover: the cost for discharge of sewage to the City; County O&M staff time;

O&M costs for materials and electricity; County Administrative costs for management billing, taxes and insurance; operating budget reserves; and capital improvement/replacement reserves.

− County ULID formation cost and funding administration and environmental assessment costs related to funding are included in construction cost assessments.

− The conservative customer growth rate is 1.0% annually − Annual revenue increases are estimated at 2.0% annually − Annual City Sewer Rate Inflation is estimated at 2.5% annually − Inflation of O&M costs is estimated at 2.5% annually − Capital reserve goals to be based on amortized system construction cost. Short term

replacement costs are amortized over 15 years and long term replacement cost is amortized over 75 years. Projected build out ERUs are used as the prorated share for current customer investment into capital reserves.

The above assumptions are provided to assist in creating representative budgets. These budget represent a basic outline of the expected costs and circumstances that will drive rate decisions. It should be acknowledged that final rate decisions are ultimately made by elected officials. The anticipated rate for the pressure sewer alternative is $54 per month for residential customers and an average of $93 per ERU for commercial customers. The residential rate is at the higher end of outside City rates for other communities in the area. Comparing the low pressure alternative


residential rate with the 2010 Median Household Income (MHI) of $26,458 for the planning area (2010 Census data), projected residential rates are approximately 2.5 percent of the median household income. The projected rates are far above the Ecology funding hardship level of 2% percent of the MHI. Simply exceeding the hardship level does not automatically qualify the project for grant funding. The project must still qualify for the funding and compete well with other funding applications. Funding is very competitive and receiving grants for projects is the exception and not the norm. If Ecology or USDA RUS funding is utilized, rates will increase to meet the capital reserve (i.e. debt service reserve) of one-tenth (1/10) of annual debt repayment requirement. The average rate increase per ERU to meet this requirement is approximately $10 per month during the term of the financing. In this case, operational rates will be 2.9% of the MHI. When combined with the assessment costs, average total cost of sewer service for residential customers may be in the range of $160 to $170 per month (over 7% of MHI). This indicates that the project will not likely be feasible for many residents without considerable grant funding assistance. One other significant aspect indentified in the evaluation of the budget process is that the project is not likely feasible unless all of the existing development within the planning area connects to the new system. Without all of the existing development connected to the system, there would be insufficient revenue to operate the collection system. Lack of sewer customers can also create the potential for septic conditions within piping networks which can cause odors, damage downstream collection system components and increase maintenance cost for flushing and pigging lines. PROJECT SCHEDULES AND IMPLEMENTATION Successful project implementation is contingent upon stakeholder participation and securing project funding. Project financing is also affected by many factors that may change the timing and scope for implementation. Financing methods such as low interest loans have specific timelines and requirements associated with appropriations and implementation. These factors are built into estimated schedules, but can be highly variable based on the actual method utilized. In summary, the project schedule should be evaluated regularly and modified as needed during project implementation. A summary of anticipated timelines for the more significant project tasks and milestones is provided in Table VII-4.


Table VII-4 Anticipated Project Tasks and Milestones

Task/Milestone Implementation Dates Review of Engineering Report by City & County March 2013 (complete)

Meeting with City Officials March 2013 (complete) Review by Illahee/Oyehut Residents April/May 2013

Meeting with Illahee/Oyehut Residents May 2013 Submit Revised Engineering Report to Ecology June 2013

Issue Applicable SEPA Document June 2013 Conduct NEPA Assessments July 2013 Submit Funding Applications October 2013

Begin LID Process April 2014 Begin Design October 2014 Construction Summer 2015

APPENDIX A

COST ESTIMATES

VACUUM SEWER COLLECTION SYSTEM COST ESTIMATES

Sub Area: Illahee/Oyehut

Total Service Units = 73 (for estimating service laterals only)

Item Unit Unit Price Units Cost

Collection System Piping & AppurtenancesContractor Mobilization LS 52,200$ 1 $52,20010-inch PVC Vacuum Main LF 65.00$ 0 $010-inch PVC Dewatering LF 9.63$ 0 $08-inch PVC Vacuum Main LF 60.00$ 2,080 $124,8008-inch PVC Dewatering LF 7.67$ 2,080 $15,9476-inch PVC Vacuum Main LF 55.00$ 2,550 $140,2506-inch PVC Dewatering LF 5.80$ 2,550 $14,7904-inch PVC Vacuum Main LF 50.00$ 3,800 $190,0004-inch PVC Dewatering LF 4.43$ 3,800 $16,8473" Service Lateral Road Crossings (30' per 4 units) LF 40.00$ 1,080 $43,2003" Service Lateral Short Side (10' per 4 units) LF 40.00$ 358 $14,30010" Isolation Valve Each 2,100.00$ 5 $10,5008" Isolation Valve Each 1,800.00$ 0 $06" Isolation Valve Each 1,500.00$ 3 $4,5004" Isolation Vavlve Each 1,200.00$ 5 $6,000Easements/Right-of-way/Property Acquisition LS -$ 0 $0

Collection System Subtotal $633,333

Surface RestorationAsphalt Paving Laterals LF 25.00$ 715 $17,875Asphalt Paving Other LF 25.00$ 2,350 $58,750Gravel Surfacing LF 9.00$ 1,900 $17,100Hydroseeding LF 1.00$ 6,100 $6,100Imported Backfill for Roadways LF 13.00$ 4,965 $64,545

Surface Restoration Subtotal $164,370

Collection System and Surface Restoration Subtotal $797,703

Construction Contingency @ 20% $159,541Sales Tax @ 8.4% $80,408

Subtotal $1,037,652

Admin., Survey, Design, Construction Mgt. and Inspection @ 30% $311,296

Total Sub-Area Construction Cost $1,348,948

Vacuum Sewer Collection Cost Estimate

Sub Area: Common Piping to Illahee/Oyehut



Collection System Piping & AppurtenancesContractor Mobilization LS 53,800$ 1 $53,8006-inch PVC Force Main LF 40.00$ 440 $17,6006-inch PVC Dewatering LF 5.10$ 440 $2,2446-inch PVC Vacuum Main LF 50.00$ 400 $20,0006-inch PVC Dewatering LF 5.80$ 400 $2,320Bore Casing and Carrier Pipe LS 325.00$ 60 $19,500Bore Pit Dewatering LS 17,500.00$ 1 $17,500Discharge Manhole and Connection to Existing Each 7,500.00$ 1 $7,500Flow Meter & Appurtenances Each 12,000.00$ 1 $12,000Install AIRVAC Model 2C-20 Vacuum Station LS 216,600.00$ 1 $216,600Vacuum Station Wiring and Piping LS 39,900.00$ 1 $39,900Vacuum Station Building LS 250,000.00$ 1 $250,000Standby Generator LS 40,000.00$ 1 $40,000Odor Control LS 20,000.00$ 1 $20,000Site Work LS 10,000.00$ 1 $10,000Electrical Service LS 20,000.00$ 1 $20,000Special Tools LS 5,000.00$ 2 $10,000Spare Parts LS 6,000.00$ 1 $6,000Trailer Mounted Vacuum Pump LS 24,000.00$ 1 $24,000Easements/Right-of-way/Property Acquisition LS 15,000.00$ 1 $15,000


Surface RestorationAsphalt Paving Laterals LF 25.00$ 0 $0Asphalt Paving Other LF 25.00$ 200 $5,000Gravel Surfacing LF 3.00$ 600 $1,800Hydroseeding LF 1.00$ 600 $600Imported Backfill for Roadways LF 13.00$ 800 $10,400




Subtotal $998,968




Sub Area: Illahee/Oyehut (Low Capacity, No Large Lots)



Collection System Piping & AppurtenancesContractor Mobilization LS 50,200$ 1 $50,20010-inch PVC Vacuum Main LF 65.00$ 0 $010-inch PVC Dewatering LF 9.63$ 0 $08-inch PVC Vacuum Main LF 60.00$ 0 $08-inch PVC Dewatering LF 7.67$ 0 $06-inch PVC Vacuum Main LF 55.00$ 2,990 $164,4506-inch PVC Dewatering LF 5.80$ 2,990 $17,3424-inch PVC Vacuum Main LF 50.00$ 5,440 $272,0004-inch PVC Dewatering LF 4.43$ 5,440 $24,1173" Service Lateral Road Crossings (30' per 4 units) LF 40.00$ 1,080 $43,2003" Service Lateral Short Side (10' per 4 units) LF 40.00$ 358 $14,30010" Isolation Valve Each 2,100.00$ 0 $08" Isolation Valve Each 1,800.00$ 0 $06" Isolation Valve Each 1,500.00$ 8 $12,0004" Isolation Vavlve Each 1,200.00$ 5 $6,000Easements/Right-of-way/Property Acquisition LS -$ 0 $0






Subtotal $998,988




Sub Area: Common Piping to Illahee/Oyehut (Low Capacity)



Collection System Piping & AppurtenancesContractor Mobilization LS 49,700$ 1 $49,7004-inch PVC Force Main LF 33.00$ 440 $14,5204-inch PVC Dewatering LF 3.83$ 440 $1,6876-inch PVC Vacuum Main LF 50.00$ 400 $20,0006-inch PVC Dewatering LF 5.80$ 400 $2,320Bore Casing and Carrier Pipe LS 325.00$ 60 $19,500Bore Pit Dewatering LS 17,500.00$ 1 $17,500Discharge Manhole and Connection to Existing Each 7,500.00$ 1 $7,500Flow Meter & Appurtenances Each 10,000.00$ 1 $10,000Install AIRVAC Model 2B-15 Vacuum Station LS 196,900.00$ 1 $196,900Vacuum Station Wiring and Piping LS 37,200.00$ 1 $37,200Vacuum Station Building LS 225,000.00$ 1 $225,000Standby Generator LS 35,000.00$ 1 $35,000Odor Control LS 20,000.00$ 1 $20,000Site Work LS 10,000.00$ 1 $10,000Electrical Service LS 20,000.00$ 1 $20,000Special Tools LS 5,000.00$ 2 $10,000Spare Parts LS 6,000.00$ 1 $6,000Trailer Mounted Vacuum Pump LS 24,000.00$ 1 $24,000Easements/Right-of-way/Property Acquisition LS 15,000.00$ 1 $15,000






Subtotal $923,473




Dewatering Cost

Pipe Trench Dewatering

Description Production/Day (feet) Dewatering Cost/Foot

2" and Smaller HDPE 1400 -$

3" HDPE 1200 3.10$

4" HDPE 1000 3.83$

6" PVC Force Main 800 5.10$

4" Vacuum Sewer 800 4.43$




2,500$ Pre-Setup Cost/Day

2,500$ Operating Cost Per Day

1 Pre-Setup Time Low Pressure (Days, Average)

2,500$ Setup Cost Low Pressure

3 Pre-Setup Time Vacuum (Days, Average)

7,500$ Setup Cost Vacuum

HDPE Production assumes pipe is assembled/fused and ready to install

Pre-Setup Days are how many days in advance dewatering is in place prior to start

Production estimates based on discussion with local contractor familiar with local construction conditions

Vault and Pit Dewatering

Description Pre-Setup Days Setup Cost Operating Days Operating Cost Total Cost

Bore Casing Pits 5 12,500$ 2 5,000$ 17,500$

Individual Grinder Vaults 0.5 1,250$ 0.5 1,250$ 2,500$

Larger Grinder Vaults 3 7,500$ 1 2,500$ 10,000$

Vacuum Vaults 0.5 1,250$ 0.5 1,250$ 2,500$

Assumes concrete ballast is set on vaults prior to placement into the ground

Direct Service Cost for Vacuum Valve Installation Unit Unit Price No. of Units CostVacuum Valves Each 4,800$ 0.5 $2,400Vacuum Valve Dewatering Each 2,500$ 0.5 $1,250

Subtotal $3,650Sales Tax @ 8.4% $307

Subtotal Installation $3,957

Direct Service Costs for Capacity and AdministrationInspection Fees (City) Each 500$ 1 $500System Development Charge (City Collection and Plant Capacity) Each 1,800$ 1 $1,800

Subtotal Capacity and Administration $2,300

Expected Average Costs to Connect to New FacilitesPump Sludge from Existing Septic Tanks and Retrofit Plumbing Each 600$ 1 $600Install 4-inch Diameter Gravity Side Sewer to Pump Pit Each 750$ 1 $750

Total Average Site Specific Cost $1,350

Total Direct Service Cost $7,607

Private Side Sewer and Septic Pumping is expected to be completed by property owners directly

and is not included in project costs

Electrical power installation and O&M cost is included in collection system costs

Vacuum Sewer Collection System

Direct Service Costs to Residential and Small Commercial per ERU

Total Service Units = 143 (for current year/existing)

Annual Operation and Maintenance Costs Unit Unit Price Units CostAnnual Labor to Maintain Vacuum Station (proportional) Manhr 40.00$ 300 12,000.00$ Annual Labor to Maintain Piping (proportional) Manhr 40.00$ 52 2,080.00$ Annual Labor to Maintain Vacuum Valves (per Valve) Manhr 40.00$ 72 2,880.00$ Administrative Services ($30 per service unit/year) $/ Svc Unit 30.00$ 143 4,290.00$

Vacuum Station Power Cost per service unit (proportional) $/ Svc Unit 13.20$ 143 1,887.60$

Total Annual Labor and Electricity $23,138

Assume no electrical power from customer side

Labor Includes Benefits

Vacuum Collection System Cost Data

Annual Hours Vacuum Station Operation 300 hours

Total Service Units 143 Current Service Units

2.10 hours per service unit

Annaul Vaccum System Piping Labor 52 hours (per full system)

0.36 hours per service unit

Annual Vacuum Valve Labor 1.00 hours per valve (manufacturer indicates 1.75)

Annual Power Cost per Vacuum Station 7,000$

Power Cost 1.10$ per month per svc unit

Replacement Cost Estimate Cost Interval (years) Quantity Total Cost Cost/YearVacuum Pumps 19,220$ 15 2 38,440.00$ 2,562.67$ Sewage Pumps 14,430$ 15 2 28,860.00$ 1,924.00$ Collection Tank 26,000$ 30 1 26,000.00$ 866.67$ Control Panel 15,598$ 20 1 15,598.00$ 779.90$ Misc. Equipment 2,000$ 15 1 2,000.00$ 133.33$ Vacuum Valves 40$ 15 72 2,880.00$ 192.00$ Valve Controller 40$ 10 72 2,880.00$ 288.00$ Misc. Valve Parts 20$ 10 72 1,440.00$ 144.00$

Total Average Annual Equipment Replacement Cost 6,890.57$

Grinder Pump Tank and Piping replacement is beyond 30 years.

Vacuum Sewer Collection O&M Cost Estimate

20

14

20

15

20

16

20

17

20

18

20

19

20

20

Ex

pe

ns

es

- O

pe

rati

on

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rog

ram

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21

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0$

21

,80

0$

22

,30

0$

2

2,9

00

$

23

,50

0$

24

,10

0$

24

,70

0$

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en

tia

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erv

ice

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arg

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or

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of

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ore

s5

7,0

28

$

58

,92

5$

60

,88

1$

6

2,8

98

$

64

,97

8$

67

,12

3$

69

,33

5$

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om

me

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Ch

arg

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or

City

of

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7,7

52

$

18

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6$

19

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2$

2

0,1

23

$

21

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7$

22

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9$

23

,83

7$

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es

96

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10

2,8

13

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1

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1$

11

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11

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22

$

11

7,8

72

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12

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5$

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12

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mm

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19

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67

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Op

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2$

64

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%

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row

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1.7

5$

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7.8

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LOW PRESSURE SEWER COLLECTION SYSTEM COST ESTIMATES

Sub Area: Illahee/Oyehut

Total Service Units = 143 (for estimating service tees only)


Collection System Piping & AppurtenancesContractor Mobilization LS 38,800$ 1 $38,8006-inch PVC Force Main LF 40.00$ 0 $06-inch PVC Dewatering LF 5.10$ 0 $04-inch HDPE LF 35.00$ 1,120 $39,2004-inch HDPE Dewatering LF 3.83$ 1,120 $4,2933-inch HDPE LF 30.00$ 2,780 $83,4003-inch HDPE Dewatering LF 3.10$ 2,780 $8,6182-inch HDPE LF 26.00$ 3,540 $92,0401.5-inch HDPE LF 23.00$ 740 $17,020Service Lateral Road Crossings (30' per 4 units) LF 23.00$ 1,080 $24,840Fused Wye, Adapter and Valve (1 per 2 service units) Each 500.00$ 72 $36,000Elec. Power Service (1 per 6 service units) Each 3,200.00$ 24 $76,800Isolation Valves Each 1,400.00$ 8 $11,200Air Release Valves (3-inch) Each 5,000.00$ 2 $10,000Clean Outs Each 1,750.00$ 9 $15,750Easements/Right-of-way/Property Acquisition LS -$ 1 $0






Subtotal $770,635



Low Pressure Sewer Collection Cost Estimate

Sub Area: Common Piping to Illahee/Oyehut



Collection System Piping & AppurtenancesContractor Mobilization LS 8,300$ 1 $8,3006-inch PVC Force Main LF 40.00$ 440 $17,6006-inch PVC Dewatering LF 5.10$ 440 $2,2444-inch HDPE LF 35.00$ 400 $14,0004-inch HDPE Dewatering LF 3.83$ 400 $1,5333-inch HDPE LF 29.00$ 0 $03-inch HDPE Dewatering LF 3.10$ 0 $02-inch HDPE LF 26.00$ 0 $0Bore Casing and Carrier Pipe LS 325.00$ 60 $19,500Bore Pit Dewatering LS 17,500.00$ 1 $17,500Discharge Manhole and Connection to Existing Each 8,000.00$ 1 $8,000Flow Meter & Appurtenances Each 12,000.00$ 1 $12,000Isolation Valves Each 1,700.00$ 2 $3,400Air Release Valves (3-inch) Each 5,000.00$ 1 $5,000Clean Outs Each 2,000.00$ 1 $2,000Easements/Right-of-way/Property Acquisition LS -$ 1 $0






Subtotal $164,808


Total Sub-Area Construction Cost $214,250


Sub Area: Illahee/Oyehut (Low Capacity, No Large Lots)



Collection System Piping & AppurtenancesContractor Mobilization LS 38,400$ 1 $38,4006-inch PVC Force Main LF 40.00$ 0 $06-inch PVC Dewatering LF 5.10$ 0 $04-inch HDPE LF 35.00$ 220 $7,7004-inch HDPE Dewatering LF 3.83$ 220 $8433-inch HDPE LF 30.00$ 3,680 $110,4003-inch HDPE Dewatering LF 3.10$ 3,680 $11,4082-inch HDPE LF 26.00$ 3,540 $92,0401.5-inch HDPE LF 23.00$ 740 $17,020Service Lateral Road Crossings (30' per 4 units) LF 23.00$ 1,080 $24,840Fused Wye, Adapter and Valve (1 per 2 service units) Each 500.00$ 72 $36,000Elec. Power Service (1 per 6 service units) Each 3,200.00$ 24 $76,800Isolation Valves Each 1,400.00$ 8 $11,200Air Release Valves (3-inch) Each 5,000.00$ 2 $10,000Clean Outs Each 1,750.00$ 9 $15,750Easements/Right-of-way/Property Acquisition LS -$ 1 $0






Subtotal $763,402




Sub Area: Common Piping to Illahee/Oyehut (Low Capacity)



Collection System Piping & AppurtenancesContractor Mobilization LS 8,000$ 1 $8,0004-inch HDPE Force Main LF 35.00$ 440 $15,4004-inch HDPE Dewatering LF 3.83$ 440 $1,6874-inch HDPE LF 35.00$ 400 $14,0004-inch HDPE Dewatering LF 3.83$ 400 $1,5333-inch HDPE LF 29.00$ 0 $03-inch HDPE Dewatering LF 3.10$ 0 $02-inch HDPE LF 26.00$ 0 $0Bore Casing and Carrier Pipe LS 325.00$ 60 $19,500Bore Pit Dewatering LS 17,500.00$ 1 $17,500Discharge Manhole and Connection to Existing Each 8,000.00$ 1 $8,000Flow Meter & Appurtenances Each 10,000.00$ 1 $10,000Isolation Valves Each 1,700.00$ 2 $3,400Air Release Valves (3-inch) Each 5,000.00$ 1 $5,000Clean Outs Each 2,000.00$ 1 $2,000Easements/Right-of-way/Property Acquisition LS -$ 1 $0






Subtotal $158,229




Dewatering Cost

Pipe Trench Dewatering

Description Production/Day (feet) Dewatering Cost/Foot

2" and Smaller HDPE 1400 -$

3" HDPE 1200 3.10$

4" HDPE 1000 3.83$

6" PVC Force Main 800 5.10$





2,500$ Pre-Setup Cost/Day

2,500$ Operating Cost Per Day

1 Pre-Setup Time Low Pressure (Days, Average)

2,500$ Setup Cost Low Pressure

3 Pre-Setup Time Vacuum (Days, Average)

7,500$ Setup Cost Vacuum

HDPE Production assumes pipe is assembled/fused and ready to install

Pre-Setup Days are how many days in advance dewatering is in place prior to start

Production estimates based on discussion with local contractor familiar with local construction conditions

Vault and Pit Dewatering

Description Pre-Setup Days Setup Cost Operating Days Operating Cost Total Cost

Bore Casing Pits 5 12,500$ 2 5,000$ 17,500$

Individual Grinder Vaults 0.5 1,250$ 0.5 1,250$ 2,500$

Larger Grinder Vaults 3 7,500$ 1 2,500$ 10,000$

Vacuum Vaults 0.5 1,250$ 0.5 1,250$ 2,500$

Assumes concrete ballast is set on vaults prior to placement into the ground

Direct Service Cost for Grinder Pump Installation Unit Unit Price No. of Units CostGrinder Pump Pits (1 per 2 Homes) Each 4,800$ 0.5 $2,400Grinder Pump Pit Dewatering Each 2,500$ 0.5 $1,250Pump/Panel Installation Each 1,600$ 0.5 $800Service Valves Each 350$ 1 $350

Subtotal $4,800Sales Tax @ 8.4% $403

Subtotal Installation $5,203

Direct Service Costs for Capacity and AdministrationInspection Fees (County) Each 300$ 1 $300System Development Charge (City Collection and Plant Capacity) Each 1,800$ 1 $1,800

Subtotal Capacity and Administration $2,100

Expected Average Costs to Connect to New FacilitesPump Sludge from Existing Septic Tanks and Retrofit Plumbing Each 600$ 1 $600Install 4-inch Diameter Gravity Side Sewer to Pump Pit Each 750$ 1 $750

Total Average Site Specific Cost $1,350

Total Direct Service Cost $8,653

Private Side Sewer and Septic Pumping is expected to be completed by property owners directly

and is not included in project costs

Electrical power installation and O&M cost is included in collection system costs

Low Pressure Sewer Collection System

Direct Service Costs to Residential and Small Commercial per ERU

Total Service Units = 143 (for current year/existing)

Annual Operation and Maintenance Costs Unit Unit Price Units CostAnnual Labor to Maintain Pumps and Piping (5 hours/week) Manhr 40.00$ 260 10,400.00$ Administrative Services ($30 per service unit/year) $/ Svc Unit 30.00$ 143 4,290.00$ Power Cost per service unit ($0.077 per KWH x 0.746 KWH/HP x 1 HP/ grinder pump x hrs/year)

$/ Svc Unit 2.91$ 72 209.66$

Total Annual Labor and Electricity $14,900

Assume no electrical power from customer side

Labor Includes Benefits

Grinder Pump Frun Time Estimate

Grinder Pump Flow Rate 12 gpm

Average Day Flow per ERU 100 gpd

Average Day Grinder Pump Run Time 8.3 minutes/day

Average Annual Grinder Pump Run Time 3042 minutes/year

51 hours/year

Grinder Pump Life Cycle 750 hours

Grinder Pump Replcament Schedule 15 years

Replacement Cost Estimate Cost Interval (years) Quantity Total Cost Cost/YearGrinder Pump Repacement Cores 2,000$ 10 72 144,000.00$ 14,400.00$ Grinder Pump Panel 1,000$ 20 72 72,000.00$ 3,600.00$ Service Check Valve 150$ 20 72 10,800.00$ 540.00$

Total Average Annual Equipment Replacement Cost 18,540.00$

10 year grinder pump rehab/replacement interval is used to be more conservative.Grinder Pump Tank and Piping replacement is beyond 30 years.

Low Pressure Sewer Collection O&M Cost Estimate

20

14

20

15

20

16

20

17

20

18

20

19

20

20

Ex

pe

ns

es

- O

pe

rati

on

s P

rog

ram

Ba

sic

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M &

Ad

min

Co

st

14

,69

0$

15

,10

0$

15

,50

0$

1

5,9

00

$

16

,30

0$

16

,70

0$

17

,10

0$

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esid

en

tia

l S

erv

ice

Ch

arg

e f

or

City

of

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Sh

ore

s5

7,0

28

$

58

,92

5$

60

,88

1$

6

2,8

98

$

64

,97

8$

67

,12

3$

69

,33

5$

C

om

me

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Ch

arg

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or

City

of

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$

18

,19

6$

19

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2$

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23

$

21

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7$

22

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9$

23

,83

7$

T

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l O

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Ex

pe

ns

es

89

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9$

92

,22

0$

96

,01

3$

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8,9

21

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10

2,9

36

$

10

6,0

22

$

11

0,2

72

$

Re

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l C

us

tom

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12

4$

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5$

1

26

$

12

7$

12

8$

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9$

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mm

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Us

19

$

19

$

2

0$

20

$

21

$

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$

22

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55

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56

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59

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ve

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mm

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93

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94

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8$

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48

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1

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48

$

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8,1

67

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12

2,5

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s (

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-$

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-$

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-$

Mis

c.

Re

ve

nu

es

15

0$

15

3.0

0$

15

6.0

6$

1

59

.18

$

16

2.3

6$

16

5.6

1$

16

8.9

2$

T

ran

sfe

r to

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ea

r B

ud

ge

t -

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w P

res

su

re A

lte

rna

tive

APPENDIX B

LOW PRESSURE COLLECTION SYSTEM HYDRAULIC MODEL RESULTS

Pipe

Size

Req

uire

d fo

r Bui

ld-o

ut w

ithou

t Lar

ge L

ots

Build

-out

Con

ditio

n. P

ress

ure a

nd V

elocit

y with

out L

arge

Lot

s. Ill

ahee

N/Ik

t ser

ved

by 3”

HDP

E

Build

-out

Con

ditio

n. P

ress

ure a

nd V

elocit

y with

out L

arge

Lot

s. Ill

ahee

N/M

oxt s

erve

d by

2” H

DPE

(4”

from

Ikt t

o Mo

xt)

Pipe

Size

Req

uire

d fo

r Bui

ld-o

ut w

ith L

arge

Lot

s

Build

-out

Con

ditio

n. P

ress

ure a

nd V

elocit

y with

Cum

ulat

ive B

uild

Out

Dem

and

Inclu

ding

Lar

ge L

ot F

low

Illahee/Oyehut Planning Area - Hydraulic Model ResultsCumulative Build Out Demand-Including Large Lots

Network Table - Nodes Elevation Base DemaDemand Head Pressure Node ID ft GPM GPM ft psi Junc OS1 16 0 0 15.03 -0.42Junc DR1 17 -24 -24 18.37 0.59Junc I1 17 0 0 25.23 3.57Junc I2 17 0 0 31.16 6.13Junc I3 17 0 0 32.89 6.89Junc I4 17 0 0 34.63 7.64Junc I5 17 0 0 43.21 11.36Junc I6 17 0 0 47.04 13.02Junc L1 17 -12 -12 51.42 14.92Junc L2 17 -24 -24 55.1 16.51Junc L3 17 -12 -12 64.96 20.78Junc L4 17 -48 -48 72.67 24.12Junc L5 17 -36 -36 84.23 29.13Junc I7 17 -12 -12 27.27 4.45Junc I8 17 0 0 31.16 6.13Junc I9 17 0 0 32.89 6.89Junc I10 17 -12 -12 36.26 8.34Junc DR2 17 -12 -12 22.13 2.22Junc DR3 17 0 0 29.84 5.56Junc O1 17 -12 -12 42.17 10.9Junc O2 17 -24 -24 51.43 14.92Junc O3 17 -12 -12 58.2 17.85Junc O4 17 0 0 66.58 21.48Junc O5 17 0 0 85.08 29.5Junc O6 17 -36 -36 102.42 37.01Tank MH1-15 10 #N/A 276 15 2.17

-276

Network Table - Links Length Diameter RoughnessFlow Velocity Unit HeadloFriction FacStatus Link ID ft in GPM fps ft/Kft Pipe pos1 5 6 140 -276 3.13 5.96 0.02 Open Pipe pos2 560 6 140 -276 3.13 5.96 0.02 Open Pipe pi1 460 4 140 -156 3.98 14.93 0.02 Open Pipe pi2 460 4 140 -144 3.68 12.87 0.02 Open Pipe pi3 460 2 140 -12 1.23 3.78 0.027 Open Pipe pi4 460 2 140 -12 1.23 3.78 0.027 Open Pipe pi5 1100 4 140 -132 3.37 10.96 0.021 Open Pipe pi6 350 4 140 -132 3.37 10.96 0.021 Open Pipe pl1 400 4 140 -132 3.37 10.96 0.021 Open Pipe pl2 400 4 140 -120 3.06 9.18 0.021 Open Pipe pl3 400 3 140 -96 4.36 24.67 0.021 Open Pipe pl4 400 3 140 -84 3.81 19.26 0.021 Open Pipe pl5 400 2 140 -36 3.68 28.9 0.023 Open Pipe pi7 540 2 140 -12 1.23 3.78 0.027 Open Pipe pi8 540 2 140 0 0 0 0 Open Pipe pi9 540 2 140 0 0 0 0 Open Pipe pi10 430 2 140 -12 1.23 3.78 0.027 Open Pipe pd1 620 4 140 -96 2.45 6.07 0.022 Open Pipe pd2 400 3 140 -84 3.81 19.26 0.021 Open Pipe po1 640 3 140 -84 3.81 19.26 0.021 Open Pipe po2 640 3 140 -72 3.27 14.48 0.022 Open Pipe po3 990 3 140 -48 2.18 6.83 0.023 Open Pipe po4 290 2 140 -36 3.68 28.9 0.023 Open Pipe po5 640 2 140 -36 3.68 28.9 0.023 Open Pipe po6 600 2 140 -36 3.68 28.9 0.023 Open

Illahee/Oyehut Planning Area - Hydraulic Model ResultsNo Large Lots - Cumulative Build Out - 3" Ikt to Moxt

Network Table - Nodes Elevation Base DemaDemand Head Pressure Node ID ft GPM GPM ft psi Junc OS1 16 0 0 15.02 -0.43Junc DR1 17 -24 -24 16.92 -0.03Junc I1 17 -12 -12 19.11 0.91Junc I2 17 0 0 23.86 2.97Junc I3 17 0 0 46.51 12.79Junc I4 17 0 0 59.8 18.55Junc I5 17 0 0 23.86 2.97Junc I6 17 0 0 23.86 2.97Junc L1 17 0 0 23.86 2.97Junc L2 17 0 0 23.86 2.97Junc L3 17 0 0 23.86 2.97Junc L4 17 0 0 23.86 2.97Junc L5 17 0 0 23.86 2.97Junc I7 17 -12 -12 21.15 1.8Junc I8 17 -12 -12 25.9 3.86Junc I9 17 -12 -12 48.55 13.67Junc I10 17 -36 -36 72.23 23.93Junc DR2 17 -12 -12 20.69 1.6Junc DR3 17 0 0 28.39 4.94Junc O1 17 -12 -12 40.72 10.28Junc O2 17 -24 -24 49.99 14.29Junc O3 17 -12 -12 56.75 17.22Junc O4 17 0 0 65.13 20.86Junc O5 17 0 0 83.63 28.87Junc O6 17 -36 -36 100.97 36.39Tank MH1- 10 #N/A 204 15 2.17

-204

Network Table - Links Length Diameter RoughnessFlow Velocity Unit HeadloFriction FacStatus Link ID ft in GPM fps ft/Kft Pipe pos1 5 6 140 -204 2.31 3.4 0.02 Open Pipe pos2 560 6 140 -204 2.31 3.4 0.02 Open Pipe pi1 460 4 140 -84 2.14 4.74 0.022 Open Pipe pi2 460 3 140 -60 2.72 10.33 0.022 Open Pipe pi3 460 2 140 -48 4.9 49.24 0.022 Open Pipe pi4 460 2 140 -36 3.68 28.9 0.023 Open Pipe pi5 1100 4 140 0 0 0 0 Open Pipe pi6 350 4 140 0 0 0 0 Open Pipe pl1 400 4 140 0 0 0 0 Open Pipe pl2 400 4 140 0 0 0 0 Open Pipe pl3 400 3 140 0 0 0 0 Open Pipe pl4 400 3 140 0 0 0 0 Open Pipe pl5 400 2 140 0 0 0 0 Open Pipe pi7 540 2 140 -12 1.23 3.78 0.027 Open Pipe pi8 540 2 140 -12 1.23 3.78 0.027 Open Pipe pi9 540 2 140 -12 1.23 3.78 0.027 Open Pipe pi10 430 2 140 -36 3.68 28.9 0.023 Open Pipe pd1 620 4 140 -96 2.45 6.07 0.022 Open Pipe pd2 400 3 140 -84 3.81 19.26 0.021 Open Pipe po1 640 3 140 -84 3.81 19.26 0.021 Open Pipe po2 640 3 140 -72 3.27 14.48 0.022 Open Pipe po3 990 3 140 -48 2.18 6.83 0.023 Open Pipe po4 290 2 140 -36 3.68 28.9 0.023 Open Pipe po5 640 2 140 -36 3.68 28.9 0.023 Open Pipe po6 600 2 140 -36 3.68 28.9 0.023 Open

Illahee/Oyehut Planning Area - Hydraulic Model ResultsNo Large Lots - Cumulative Build Out - 4" Ikt to Moxt

Network Table - Nodes Elevation Base DemaDemand Head Pressure Node ID ft GPM GPM ft psi Junc OS1 16 0 0 15.02 -0.43Junc DR1 17 -24 -24 16.92 -0.03Junc I1 17 -12 -12 19.11 0.91Junc I2 17 0 0 20.28 1.42Junc I3 17 0 0 42.93 11.23Junc I4 17 0 0 56.22 17Junc I5 17 0 0 20.28 1.42Junc I6 17 0 0 20.28 1.42Junc L1 17 0 0 20.28 1.42Junc L2 17 0 0 20.28 1.42Junc L3 17 0 0 20.28 1.42Junc L4 17 0 0 20.28 1.42Junc L5 17 0 0 20.28 1.42Junc I7 17 -12 -12 21.15 1.8Junc I8 17 -12 -12 22.32 2.3Junc I9 17 -12 -12 44.97 12.12Junc I10 17 -36 -36 68.65 22.38Junc DR2 17 -12 -12 20.69 1.6Junc DR3 17 0 0 28.39 4.94Junc O1 17 -12 -12 40.72 10.28Junc O2 17 -24 -24 49.99 14.29Junc O3 17 -12 -12 56.75 17.22Junc O4 17 0 0 65.13 20.86Junc O5 17 0 0 83.63 28.87Junc O6 17 -36 -36 100.97 36.39Tank MH1- 10 #N/A 204 15 2.17

-204

Network Table - Links Length Diameter RoughnessFlow Velocity Unit HeadloFriction FacStatus Link ID ft in GPM fps ft/Kft Pipe pos1 5 6 140 -204 2.31 3.4 0.02 Open Pipe pos2 560 6 140 -204 2.31 3.4 0.02 Open Pipe pi1 460 4 140 -84 2.14 4.74 0.022 Open Pipe pi2 460 4 140 -60 1.53 2.54 0.023 Open Pipe pi3 460 2 140 -48 4.9 49.24 0.022 Open Pipe pi4 460 2 140 -36 3.68 28.9 0.023 Open Pipe pi5 1100 4 140 0 0 0 0 Open Pipe pi6 350 4 140 0 0 0 0 Open Pipe pl1 400 4 140 0 0 0 0 Open Pipe pl2 400 4 140 0 0 0 0 Open Pipe pl3 400 3 140 0 0 0 0 Open Pipe pl4 400 3 140 0 0 0 0 Open Pipe pl5 400 2 140 0 0 0 0 Open Pipe pi7 540 2 140 -12 1.23 3.78 0.027 Open Pipe pi8 540 2 140 -12 1.23 3.78 0.027 Open Pipe pi9 540 2 140 -12 1.23 3.78 0.027 Open Pipe pi10 430 2 140 -36 3.68 28.9 0.023 Open Pipe pd1 620 4 140 -96 2.45 6.07 0.022 Open Pipe pd2 400 3 140 -84 3.81 19.26 0.021 Open Pipe po1 640 3 140 -84 3.81 19.26 0.021 Open Pipe po2 640 3 140 -72 3.27 14.48 0.022 Open Pipe po3 990 3 140 -48 2.18 6.83 0.023 Open Pipe po4 290 2 140 -36 3.68 28.9 0.023 Open Pipe po5 640 2 140 -36 3.68 28.9 0.023 Open Pipe po6 600 2 140 -36 3.68 28.9 0.023 Open

APPENDIX C

NET PRESENT VALUE ANALYSIS

OMB CIRCULAR A-94 “APPENDIX C”

EXECUTIVE OFFICE OF THE PRESIDENT OFFICE OF MANAGEMENT AND BUDGET

WASHINGTON, D.C. 20503

January 24,2013

M-13-04

MEMORANDUM FOR THE HEADS OF DEPARTMENTS AND AGENCIES

FROM: Jeffrey D. Zient ~V Deputy Director for anagement

SUBJECT: 2013 Discount Rates for OMB Circular No. A-94

On October 29, 1992, OMB issued a revision to OMB Circular No. A-94, "Guidelines and Discount Rates for Benefit-Cost Analysis ofFederal Programs." The revision established new discount rate guidelines for use in benefit-cost and other types of economic analysis.

The revised Circular specifies certain discount rates that will be updated annually when the interest rate and inflation assumptions in the budget are changed. These discount rates are found in Appendix C of the revised Circular. The attachment to this memorandum is an update of Appendix C. It provides discount rates that will be in effect for the calendar year 2013.

The rates presented in Appendix C do not apply to regulatory analysis or benefit-cost analysis of public investment. They are to be used for lease-purchase and cost-effectiveness analysis, as specified in the Circular.

Attachment

OMB Circular No. A-94 APPENDIXC

(Revised December 2012)

DISCOUNT RATES FOR COST -EFFECTIVENESS, LEASE PURCHASE, AND RELATED ANALYSES

Effective Dates. This appendix is updated annually. This version of the appendix is valid for calendar year 2013. A copy ofthe updated appendix can be obtained in electronic form through the OMB home page at http://www.whitehouse.gov/omb/circulars a094/a94 appx-c/. The text of the Circular is found at http://www.whitehouse.gov/omb/circulars a094/, and a table ofpast years' rates is located at http://www.whitehouse.gov/sites/defauLt/f1 les/omb/assets/a94/dischist.pdf. Updates of the appendix are also available upon request from OMB's Office of Economic Policy (202-3953381).

Nominal Discount Rates. A forecast of nominal or market interest rates for calendar year 2013 based on the economic assumptions for the 2014 Budget is presented below. These nominal rates are to be used for discounting nominal flows, which are often encountered in lease-purchase analysis.

Nominal Interest Rates on Treasury Notes and Bonds of Specified Maturities (in percent)

3-Year 5-Year 7-Year 10-Year 20-Year 30-Year 0.5 1.1 1.5 2.0 2.7 3.0

Real Discount Rates. A forecast of real interest rates from which the inflation premium has been removed and based on the economic assumptions from the 2014 Budget is presented below. These real rates are to be used for discounting constant-dollar flows, as is often required in costeffectiveness analysis.

Real Interest Rates on Treasury Notes and Bonds of Specified Maturities (in percent)

3-Year 5-Year 7-Year 10-Year 20-Year 30-Year -1.4 -0.8 -0.4 0.1 0.8 1.1

Analyses ofprograms with terms different from those presented above may use a linear interpolation. For example, a four-year project can be evaluated with a rate equal to the average of the three-year and five-year rates. Programs with durations longer than 30 years may use the 30-year interest rate.

http://www.whitehouse.gov/sites/default/files/omb/assets/a94/dischist.pdf

http://www.whitehouse.gov/omb/circulars_a094/

http://www.whitehouse.gov/omb/circulars_a094/a94_appx-c/

SEATTLE AREA CPI PROJECTIONS

Forecast of Seattle CPI-U, All items (1982-84=100)

Updated 9-19-12

Index: Annual

1982-84=100 growth rate

2000 (actual) 179.2 3.7%

2001 (actual) 185.7 3.6%

2002 (actual) 189.3 1.9%

2003 (actual) 192.3 1.6%

2004 (actual) 194.7 1.2%

2005 (actual) 200.2 2.8%

2006 (actual) 207.6 3.7%

2007 (actual) 215.656 3.9%

2008 (actual) 224.719 4.2%

2009 (actual) 226.028 0.6%

2010 (actual) 226.693 0.3%

2011 (actual) 232.765 2.7%

2012 238.718 2.6%

2013 244.018 2.2%

2014 250.088 2.5%

2015 256.120 2.4%

2016 262.138 2.3%

2017 268.581 2.5%

2018 275.207 2.5%

2019 281.994 2.5%

2020 288.951 2.5%

NOTE: CPI-U covers all urban consumers.

Source: U.S. Bureau of Labor Statistics; The Puget Sound Economic

Forecaster, prepared by Conway Pedersen Economics, Inc.

NET PRESENT VALUE VACUUM SEWER COLLECTION SYSTEM

Present Net Value Analysis

Vacuum Sew

er Collection System

Discount Rate

1.1%

30 Year Real Discount Rate 2013

O&M Inflation

2.5%

Based on Seattle Area CPI Projections

Property Value Growth

2.0%

Customer Growth

1.5%

Year

01

23

45

67

8Debt Service (Principal and Interest)

(377,892)

(368,942)

(359,992)

(351,042)

(342,092)

(333,142)

(324,192)

(315,242)

(306,292)

Less Personnel Costs

(21,250)

(21,781)

(22,326)

(22,884)

(23,456)

(24,042)

(24,643)

(25,260)

(25,891)

Less Equipment Replacement/Upgrade

-

-

-

-

-

-

-

-

-

Less Annual Electrical Power Cost

(2,032)

(2,109)

(2,190)

(2,273)

(2,359)

(2,448)

(2,540)

(2,635)

(2,733)

Net cash flow

(401,174)

(392,833)

(384,508)

(376,199)

(367,907)

(359,632)

(351,375)

(343,136)

(334,915)

Present value factor

1.0000

0.9891

0.9784

0.9677

0.9572

0.9468

0.9365

0.9263

0.9162

PV of cash flow

(401,174)

(388,559)

(376,186)

(364,053)

(352,155)

(340,489)

(329,052)

(317,840)

(306,850)

Cumulative PV

(401,174)

(789,733)

(1,165,919)

(1,529,972)

(1,882,127)

(2,222,616)

(2,551,668)

(2,869,508)

(3,176,358)

10-Year

20-Year

30-Year

Net present value - Vacuum

-$3,762,917

-$6,038,960

-$6,535,826

Net present value - Low Pressure

-$2,709,721

-$4,507,748

-$5,029,280

Difference

-$1,053,196

-$1,531,212

-$1,506,547

Operation and Maintenance (O&M) Cost

Collection System Maintenance

01

23

45

67

8O&M Labor

16,960

$

17,384

$

17,819

$

18,264

$

18,721

$

19,189

$

19,668

$

20,160

$

20,664

$

Administration

4,290

$

4,397

$

4,507

$

4,620

$

4,735

$

4,854

$

4,975

$

5,099

$

5,227

$

Total

21,250

$

21,781

$

22,326

$

22,884

$

23,456

$

24,042

$

24,643

$

25,260

$

25,891

$

Pump and Valve O&M Cost Projections

Total Vacuum Valve Units

7273

7475

7677

7879

80Additional Units from Growth

01

11

11

11

1Replace Initial Valve Controller & Parts (10, 20 & 30-Year)

00

00

00

00

0Replace Valve Controller & Parts From Growth (Beginning Year 11)

00

00

00

00

0Valve Controller and Parts Replacement Cost

-$

-$

-$

-$

-$

-$

-$

-$

-$

Refurb. Initial Vacuum Valves (15, 30 Year)

00

00

00

00

0Refurb. Vacuum Valves from Growth (Beginning Year 16)

00

00

00

00

0Refurb. Vacuum Valve Cost

-$

-$

-$

-$

-$

-$

-$

-$

-$

Replace Pumps & Misc. Equipment (15 & 30-Year)

-$

-$

-$

-$

-$

-$

-$

-$

-$

Replace Collection Tank (30-Year)

-$

-$

-$

-$

-$

-$

-$

-$

-$

Refurb. Control Panel (20-Year)

-$

-$

-$

-$

-$

-$

-$

-$

-$

Vacuum Station Replacement Cost

-$

-$

-$

-$

-$

-$

-$

-$

-$

Annual Power Cost Per Service Unit

13.20

$

13.53

$

13.87

$

14.21

$

14.57

$

14.93

$

15.31

$

15.69

$

16.08

$

Power Services (1 per 4 Pumps)

143

145

147

149

151

153

155

157

159

Annual Basic Service Power Service Charge

144.00

$

147.60

$

151.29

$

155.07

$

158.95

$

162.92

$

167.00

$

171.17

$

175.45

$

Total Power Cost

2,031.60

$

2,109.45

$

2,189.92

$

2,273.10

$

2,359.07

$

2,447.91

$

2,539.73

$

2,634.60

$

2,732.63

$

Pa

ge

1 o

f 3


Vacuum Sew


Discount Rate

O&M Inflation


Customer Growth

Year

Debt Service (Principal and Interest)




Net cash flow


PV of cash flow

Cumulative PV



O&M Labor

Administration

Total



Additional Units from Growth

Replace Initial Valve Controller & Parts (10, 20 & 30-Year)

Replace Valve Controller & Parts From Growth (Beginning Year 11)

Valve Controller and Parts Replacement Cost


Refurb. Vacuum Valves from Growth (Beginning Year 16)

Refurb. Vacuum Valve Cost








Total Power Cost

910

1112

1314

1516

17(297,342)

(288,392)

(279,442)

(270,491)

(261,541)

(252,591)

(243,641)

(234,691)

(225,741)

(26,538)

(27,202)

(27,882)

(28,579)

(29,293)

(30,026)

(30,776)

(31,546)

(32,334)

-

(5,530)

(79)

(81)

(83)

(85)

(104,625)

(148)

(152)

(2,834)

(2,939)

(3,047)

(3,158)

(3,274)

(3,393)

(3,516)

(3,643)

(3,774)

(326,714)

(324,062)

(310,449)

(302,309)

(294,191)

(286,095)

(382,558)

(270,028)

(262,002)

0.9062

0.8964

0.8866

0.8770

0.8674

0.8580

0.8487

0.8394

0.8303

(296,079)

(290,480)

(275,250)

(265,117)

(255,191)

(245,467)

(324,661)

(226,668)

(217,538)

(3,472,436)

(3,762,917)

(4,038,166)

(4,303,284)

(4,558,474)

(4,803,941)

(5,128,603)

(5,355,271)

(5,572,809)

910

1112

1314

1516

1721,181

$

21,710

$

22,253

$

22,809

$

23,380

$

23,964

$

24,563

$

25,177

$

25,807

$

5,358

$

5,492

$

5,629

$

5,770

$

5,914

$

6,062

$

6,213

$

6,369

$

6,528

$

26,538

$

27,202

$

27,882

$

28,579

$

29,293

$

30,026

$

30,776

$

31,546

$

32,334

$

8182

8384

8586

8788

891

11

11

11

11

072

00

00

00

00

01

11

11

11

-$

5,529.97

$

78.73

$

80.69

$

82.71

$

84.78

$

86.90

$

89.07

$

91.30

$

00

00

00

720

00

00

00

00

11

-$

-$

-$

-$

-$

-$

4,171.10

$

59.38

$

60.86

$

-$

-$

-$

-$

-$

-$

100,367.06

$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

100,367.06

$

-$

-$

16.48

$

16.90

$

17.32

$

17.75

$

18.20

$

18.65

$

19.12

$

19.60

$

20.09

$

161

163

165

167

169

171

173

175

177

179.84

$

184.33

$

188.94

$

193.66

$

198.51

$

203.47

$

208.55

$

213.77

$

219.11

$

2,833.92

$

2,938.56

$

3,046.67

$

3,158.34

$

3,273.69

$

3,392.83

$

3,515.89

$

3,642.98

$

3,774.22

$

Pa

ge

2 o

f 3


Vacuum Sew


Discount Rate

O&M Inflation


Customer Growth

Year





Net cash flow


PV of cash flow

Cumulative PV



O&M Labor

Administration

Total




Replace Initial Valve Controller & Parts (10, 20 & 30-Year)

Replace Valve Controller & Parts From Growth (Beginning Year 11)

Valve Controller and Parts Replacement Cost


Refurb. Vacuum Valves from Growth (Beginning Year 16)

Refurb. Vacuum Valve Cost








Total Power Cost

1819

2021

2223

2425

26(216,791)

(207,841)

-

(33,143)

(33,971)

(34,821)

(35,691)

(36,583)

(37,498)

(38,435)

(39,396)

(40,381)

(156)

(160)

(32,802)

(168)

(172)

(176)

(181)

(185)

(190)

(3,910)

(4,050)

(4,194)

(4,343)

(4,497)

(4,656)

(4,821)

(4,990)

(5,165)

(253,999)

(246,022)

(71,817)

(40,202)

(41,253)

(42,331)

(43,437)

(44,572)

(45,736)

0.8213

0.8123

0.8035

0.7947

0.7861

0.7775

0.7691

0.7607

0.7524

(208,599)

(199,849)

(57,703)

(31,951)

(32,429)

(32,914)

(33,407)

(33,906)

(34,414)

(5,781,408)

(5,981,256)

(6,038,960)

(6,070,910)

(6,103,339)

(6,136,253)

(6,169,660)

(6,203,566)

(6,237,980)

1819

2021

2223

2425

2626,452

$

27,113

$

27,791

$

28,486

$

29,198

$

29,928

$

30,676

$

31,443

$

32,229

$

6,691

$

6,858

$

7,030

$

7,205

$

7,386

$

7,570

$

7,759

$

7,953

$

8,152

$

33,143

$

33,971

$

34,821

$

35,691

$

36,583

$

37,498

$

38,435

$

39,396

$

40,381

$

9091

9293

9495

9697

981

11

11

11

11

00

720

00

00

01

11

11

11

11

93.58

$

95.92

$

7,177.14

$

100.77

$

103.29

$

105.88

$

108.52

$

111.24

$

114.02

$

00

00

00

00

01

11

11

11

11

62.39

$

63.95

$

65.54

$

67.18

$

68.86

$

70.58

$

72.35

$

74.16

$

76.01

$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

-$

25,559.14

$

-$

-$

-$

-$

-$

-$

-$

-$

25,559.14

$

-$

-$

-$

-$

-$

-$

20.59

$

21.10

$

21.63

$

22.17

$

22.72

$

23.29

$

23.88

$

24.47

$

25.08

$

179

181

183

185

187

189

191

193

195

224.59

$

230.21

$

235.96

$

241.86

$

247.91

$

254.10

$

260.46

$

266.97

$

273.64

$

3,909.75

$

4,049.70

$

4,194.20

$

4,343.40

$

4,497.43

$

4,656.45

$

4,820.62

$

4,990.08

$

5,165.00

$

Pa

ge

3 o

f 3

NET PRESENT VALUE LOW PRESSURE SEWER COLLECTION SYSTEM


Low Pressure Sew

er Collection System Discount Rate

1.1%

30 Year Real Discount Rate 2013

O&M Inflation

2.5%

Based on Seattle Area CPI Projections


2.5%

Customer Growth

1.5%

Year

01

23

45

67

8Debt Service (Principal and Interest)

(253,781)

(247,770)

(241,760)

(235,749)

(229,739)

(223,728)

(217,717)

(211,707)

(205,696)


(14,690)

(15,057)

(15,434)

(15,820)

(16,215)

(16,620)

(17,036)

(17,462)

(17,898)


-

-

-

-

-

-

-

-

-


(2,595)

(2,660)

(2,878)

(2,950)

(3,023)

(3,099)

(3,343)

(3,427)

(3,513)

Net cash flow

(271,066)

(265,487)

(260,071)

(254,518)

(248,977)

(243,447)

(238,097)

(232,595)

(227,107)


1.0000

0.9891

0.9784

0.9677

0.9572

0.9468

0.9365

0.9263

0.9162

PV of cash flow

(271,066)

(262,599)

(254,443)

(246,301)

(238,317)

(230,488)

(222,970)

(215,448)

(208,076)

Cumulative PV

(271,066)

(533,665)

(788,107)

(1,034,408)

(1,272,724)

(1,503,213)

(1,726,183)

(1,941,631)

(2,149,707)

10-Year

20-Year

30-Year

Net present value - Low Pressure

-$2,709,721

-$4,507,748

-$5,029,280

Net present value - Vacuum

-$3,762,917

-$6,038,960

-$6,535,826

difference

$1,053,196

$1,531,212

$1,506,547



01

23

45

67

8O&M Labor

10,400

$

10,660

$

10,927

$

11,200

$

11,480

$

11,767

$

12,061

$

12,362

$

12,671

$

Administration

4,290

$

4,397

$

4,507

$

4,620

$

4,735

$

4,854

$

4,975

$

5,099

$

5,227

$

Total

14,690

$

15,057

$

15,434

$

15,820

$

16,215

$

16,620

$

17,036

$

17,462

$

17,898

$

Grinder Pump O&M Cost Projections

Total Grinder Pump Units

7273

7475

7677

7879

80Additional Units from Growth

01

11

11

11

1Rehab/Replace Initial Pump Units (10, 20 & 30-Year)

00

00

00

00

0Rehab/Replace Pump Units From Growth (Beginning Year 11)

00

00

00

00

0Pump Replacement Cost

-$

-$

-$

-$

-$

-$

-$

-$

-$

Refurb./Replace Initial Panel Units (20-Year)

00

00

00

00

0Replace Units From Growth (Beginning Year 21)

00

00

00

00

0Pump Panel Replacement Cost

-$

-$

-$

-$

-$

-$

-$

-$

-$

Replace Initial Check Valves (20-Year)

00

00

00

00

0Replace Check Valves From Growth (Beginning Year 21)

00

00

00

00

0Check Valve Replacement Cost

-$

-$

-$

-$

-$

-$

-$

-$

-$

Annual Power Cost Per Grinder Pump

2.91

$

2.98

$

3.06

$

3.14

$

3.21

$

3.29

$

3.38

$

3.46

$

3.55

$


1818

1919

1919

2020

20Annual Basic Power Service Charge per Service

144.00

$

147.60

$

151.29

$

155.07

$

158.95

$

162.92

$

167.00

$

171.17

$

175.45

$

Total Power Cost

2,594.91

$

2,659.78

$

2,877.57

$

2,949.51

$

3,023.25

$

3,098.83

$

3,343.29

$

3,426.88

$

3,512.55

$

Page 1

of

3


Low Pressure Sew


O&M Inflation


Customer Growth

Year





Net cash flow


PV of cash flow

Cumulative PV



O&M Labor

Administration

Total




Rehab/Replace Initial Pump Units (10, 20 & 30-Year)

Rehab/Replace Pump Units From Growth (Beginning Year 11)

Pump Replacement Cost


Replace Units From Growth (Beginning Year 21)

Pump Panel Replacement Cost


Replace Check Valves From Growth (Beginning Year 21)

Check Valve Replacement Cost



Annual Basic Power Service Charge per Service

Total Power Cost

910

1112

1314

1516

17(199,686)

(193,675)

(187,664)

(181,654)

(175,643)

(169,633)

(163,622)

(157,611)

(151,601)

(18,346)

(18,804)

(19,275)

(19,756)

(20,250)

(20,757)

(21,276)

(21,807)

(22,353)

-

(184,332)

(2,624)

(2,690)

(2,757)

(2,826)

(2,897)

(2,969)

(3,043)

(3,600)

(3,875)

(3,972)

(4,071)

(4,173)

(4,480)

(4,592)

(4,707)

(4,825)

(221,632)

(400,686)

(213,535)

(208,171)

(202,823)

(197,696)

(192,386)

(187,095)

(181,821)

0.9062

0.8964

0.8866

0.8770

0.8674

0.8580

0.8487

0.8394

0.8303

(200,850)

(359,164)

(189,324)

(182,560)

(175,935)

(169,621)

(163,270)

(157,052)

(150,965)

(2,350,557)

(2,709,721)

(2,899,045)

(3,081,605)

(3,257,540)

(3,427,161)

(3,590,432)

(3,747,484)

(3,898,448)

910

1112

1314

1516

1712,988

$

13,313

$

13,646

$

13,987

$

14,337

$

14,695

$

15,062

$

15,439

$

15,825

$

5,358

$

5,492

$

5,629

$

5,770

$

5,914

$

6,062

$

6,213

$

6,369

$

6,528

$

18,346

$

18,804

$

19,275

$

19,756

$

20,250

$

20,757

$

21,276

$

21,807

$

22,353

$

8182

8384

8586

8788

891

11

11

11

11

072

00

00

00

00

01

11

11

11

-$

184,332.17

$

2,624.17

$

2,689.78

$

2,757.02

$

2,825.95

$

2,896.60

$

2,969.01

$

3,043.24

$

00

00

00

00

00

00

00

00

00

-$

-$

-$

-$

-$

-$

-$

-$

-$

00

00

00

00

00

00

00

00

00

-$

-$

-$

-$

-$

-$

-$

-$

-$

3.64

$

3.73

$

3.82

$

3.92

$

4.01

$

4.11

$

4.22

$

4.32

$

4.43

$

2021

2121

2122

2222

22179.84

$

184.33

$

188.94

$

193.66

$

198.51

$

203.47

$

208.55

$

213.77

$

219.11

$

3,600.36

$

3,874.70

$

3,971.57

$

4,070.86

$

4,172.63

$

4,480.42

$

4,592.43

$

4,707.24

$

4,824.92

$

Page 2

of

3


Low Pressure Sew


O&M Inflation


Customer Growth

Year





Net cash flow


PV of cash flow

Cumulative PV



O&M Labor

Administration

Total




Rehab/Replace Initial Pump Units (10, 20 & 30-Year)

Rehab/Replace Pump Units From Growth (Beginning Year 11)

Pump Replacement Cost


Replace Units From Growth (Beginning Year 21)

Pump Panel Replacement Cost


Replace Check Valves From Growth (Beginning Year 21)

Check Valve Replacement Cost



Annual Basic Power Service Charge per Service

Total Power Cost

1819

2021

2223

2425

26(145,590)

(139,580)

-

(22,911)

(23,484)

(24,071)

(24,673)

(25,290)

(25,922)

(26,570)

(27,234)

(27,915)

(3,119)

(3,197)

(374,670)

(5,291)

(5,423)

(5,559)

(5,697)

(5,840)

(5,986)

(5,170)

(5,299)

(5,432)

(5,568)

(5,955)

(6,104)

(6,256)

(6,413)

(6,847)

(176,791)

(171,560)

(404,173)

(35,531)

(36,668)

(37,584)

(38,524)

(39,487)

(40,748)

0.8213

0.8123

0.8035

0.7947

0.7861

0.7775

0.7691

0.7607

0.7524

(145,191)

(139,362)

(324,746)

(28,238)

(28,824)

(29,223)

(29,628)

(30,038)

(30,660)

(4,043,639)

(4,183,002)

(4,507,748)

(4,535,986)

(4,564,810)

(4,594,033)

(4,623,661)

(4,653,700)

(4,684,360)

1819

2021

2223

2425

2616,220

$

16,626

$

17,042

$

17,468

$

17,904

$

18,352

$

18,811

$

19,281

$

19,763

$

6,691

$

6,858

$

7,030

$

7,205

$

7,386

$

7,570

$

7,759

$

7,953

$

8,152

$

22,911

$

23,484

$

24,071

$

24,673

$

25,290

$

25,922

$

26,570

$

27,234

$

27,915

$

9091

9293

9495

9697

981

11

11

11

11

00

720

00

00

01

11

11

11

11

3,119.32

$

3,197.30

$

239,238.00

$

3,359.16

$

3,443.14

$

3,529.22

$

3,617.45

$

3,707.89

$

3,800.59

$

00

720

00

00

00

00

11

11

11

-$

-$

117,980.38

$

1,679.58

$

1,721.57

$

1,764.61

$

1,808.73

$

1,853.94

$

1,900.29

$

00

710

00

00

00

00

11

11

11

-$

-$

17,451.27

$

251.94

$

258.24

$

264.69

$

271.31

$

278.09

$

285.04

$

4.54

$

4.66

$

4.77

$

4.89

$

5.01

$

5.14

$

5.27

$

5.40

$

5.53

$

2323

2323

2424

2424

25224.59

$

230.21

$

235.96

$

241.86

$

247.91

$

254.10

$

260.46

$

266.97

$

273.64

$

5,170.13

$

5,299.38

$

5,431.87

$

5,567.67

$

5,954.76

$

6,103.63

$

6,256.22

$

6,412.63

$

6,846.59

$

Page 3

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3