chapter 8 capital improvement program - ci.lacey.wa.us...feasibility, advantages and disadvantages...

Chapter 8 Capital Improvement Program

City of Lacey 2005 Wastewater Comprehensive Plan Update \\7348101\TOC.doc

CHAPTER 8

Capital Improvement Program 8.1 INTRODUCTION

Hydraulic modeling results and verification by City staff indicate that the existing collection system has adequate capacity to convey current wastewater flows. There are locations within the modeled system that are currently operating in a slightly overcapacity condition but do not appear to present immediate hydraulic concerns. However the residential and commercial customers that must be served by Lacey’s wastewater system has been growing at an unprecedented rate in recent years. Lacey’s planning staff anticipates this trend to continue for the near term.

The hydraulic analysis conducted and presented in Chapter 7 identified existing facilities that will require upsizing to meet projected growth. The location of future gravity interceptor sewers, lift stations and force mains were also identified and modeled. The year 2010, 2024 and build out models each contain proposed conveyance facilities that are adequately sized to convey peak hour wastewater flows for that year. These improvements were based upon projected growth as summarized in Table 7.2 and are shown in Figure 8-1. A large scale copy of Figure 8-1 is located in the back of this document.

It is intended that a mix of public and developer funds will finance future improvements and extensions, with the City taking part when improvements benefit the City. Development proponents should be required to provide sufficient sewer utility infrastructure to serve any development that will discharge to Lacey’s existing wastewater system.

The intent of the Capital Improvement Plan presented herein is to determine and present the upgrades and extensions to the existing interceptor system that the hydraulic analysis predicted will be required to adequately convey future peak hour flows. The scope of the analysis was limited to the interceptor systems. Future development will require that additional local conveyance facilities be constructed.

It should be noted that the size and configuration of future conveyance facilities are dependant upon the manner in which development actually occurs. Proposed gravity sewer sizes are based upon pipe slopes that were estimated using the assumption that manhole inverts will be installed six feet below the existing ground elevation. Actual construction may vary substantially from this assumption. Therefore, pipe sizes should be viewed as approximate. Final pipe diameters should be established during the pre-design phase of each project as it occurs.

City of Lacey 2005 Wastewater Comprehensive Plan Update \\7348101\Chapter 8.doc

8-1

8.2 SIX-YEAR CAPITAL IMPROVEMENT PLAN (THROUGH YEAR 2010)

Nine projects are proposed for the Six Year Capital Improvement Plan. They are listed in order of priority in Table 8.1 below. It is recommended that the City implement CIP No. 1 prior to or concurrent with implementing CIP No. 2, and so on.

Table 8.1 Capital Improvement Projects

Through Year 2010

CIP No. Title Brief Description of Project CIP No. 1 STEP Force Main

Analysis Evaluate feasibility of using existing STEP mains to convey future wastewater flows and associated improvements for effectively conveying wastewater.

CIP No. 2 Ruddell Rd. Interceptor Study

Conduct detailed flow and capacity analysis; determine when improvements are required

CIP No. 3 Lift Station Nos. 14 & 18 Upgrade

Prepare design report, construction plans and specifications. Possible modifications include replacing existing pumps and wetwell volume.

CIP No. 4 Lift Station Nos. 8, 11 & 12 Control Cabinet Replacement

Upgrade lift stations with new electrical control panels and miscellaneous electrical components

CIP No. 5 Pacific Ave. Sewer and Lift Station No. 21 – Convert Force Main to Gravity

Convert force main to gravity and conduct engineering study to determine feasibility of decommissioning or modifying Lift Station No. 21

CIP No. 6 Draham Rd. NE Lift Station Preliminary Design Report

Prepare preliminary design report

CIP No. 7 Lift Station No. 9 Upgrade Preliminary Design Report

Prepare preliminary design report

CIP No. 8 Mullen Rd. SE Force Main

Design and construct approximately 3,500 LF of 4-inch force main

CIP No. 9 Flow Monitoring Program

Develop program to establish permanent flow monitoring sites within the collection system

Following are detailed descriptions of each capital improvement project.

City of Lacey 2005 Wastewater Comprehensive Plan Update \\7348101\Chapter 8.doc 8-3

CIP No. 1 - STEP Force Main Analysis

Sewer system improvements developed in this 2005 Plan Update were based on the assumption that no future connections will be made to the existing STEP system. All future sewer service will be provided through the construction of conventional gravity sewers and lift stations. This will require that, prior to 2010, new gravity sewers and three lift stations in the Carpenter Rd. SE corridor and along the abandoned BNRR right of way will be required to serve new growth in the southern and southeastern areas of the UGA. These proposed sewer lines will be constructed parallel to existing large diameter STEP mains.

The large diameter STEP mains, generally sized 6- through 16-inches in diameter are shown highlighted in Figure 8-2. The mains convey relatively sediment-free STEP wastewater and are hydraulically independent from the rest of Lacey’s wastewater collection system. The connection to the main wastewater system occurs at or near manhole WB103 located near the eastern intersection of Lacey Blvd SE and Pacific Ave. SE.


Figure 8-2 STEP Force Main Analysis

According to City staff, the large diameter STEP mains were sized to convey wastewater flows that were anticipated to occur under full build out conditions. As such, there is a considerable amount of hydraulic capacity that could remain unused in the STEP system if future flows are redirected to new conventional sewers. CIP No. 1 will analyze the feasibility, advantages and disadvantages of directing future non-STEP wastewater flows into the large diameter STEP mains. In the event that future non-STEP flows are directed to these STEP mains, the recommended improvements in the Carpenter Rd. SE and BNRR systems described in Section 8.4 below should be revised to reflect this change.

CIP No. 1 may include, but not necessarily be limited to the tasks listed below.


Table 8.2 CIP No. 1

STEP Force Main Analysis Tasks

Task Title 1 Prepare plan and profile views of the STEP main system piping and

appurtenances. 2 Define existing flows conveyed and the remaining hydraulic capacity

throughout the STEP force main system 3 Evaluate the impact on existing STEP services if additional pumped

wastewater flows are added. 4 Evaluate feasibility and cost of changing existing STEP/Submersible

pumps to pumps capable of pumping solids. 5 Define revisions and/or upgrades required at existing

STEP/Submersible lift stations and at individual STEP connections. 6 Evaluate the impact on the operation and maintenance program of

introducing higher solids-content wastewater into the large diameter STEP mains.

7 Determine additional facilities and/or appurtenances required. 8 Evaluate need for odor control 9 Prepare report


CIP No. 2 - Ruddell Rd. Interceptor Study Interceptor Analysis

The interceptor located in the Ruddell Rd. SE corridor is approaching capacity. Growth in the southwest portion and the southern portion of the UGA in areas tributary to lift stations 9, 18 22, and 37 and from proposed lift stations along Mullen Rd. SE are anticipated to generate flows that could exceed the capacity within portions of the interceptor by the year 2010. The Ruddell Rd interceptor is shown highlighted in Figure 8-3.

Figure 8-3 Ruddell Rd. Interceptor

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Ruddell Rd Interceptor

Lift Station 9

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Lift Station 18

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Gravity Sewers Leading to LS 9


Gravity Sewers Leading to LS 9

Hydraulic analysis results indicate that by 2010 the existing 18-inch gravity sewer line beginning at the intersection of SE Mt. Tahoma Dr and SE 54th Ave. running north to SE 50th Ave, then easterly to Ruddell Rd. SE, and then north to LS 9 will exceed its capacity. The analysis also indicates that year 2010 and 2024 flows both require a 21-inch diameter gravity sewer. Build out flows would require a 27-inch line.

Activities conducted as part of CIP No. 2 will define in detail the remaining capacity of the Ruddell Rd interceptor and the gravity sewers leading to LS 9. The study will establish when improvements are required. The study may include, but will not necessarily be limited to the tasks listed below.

Table 8.3 CIP No. 2

Ruddell Rd. Interceptor Study Tasks

Task Title 1 Refine existing and future population projections and define flows 2 Conduct flow monitoring to refine estimate of existing flows 3 Conduct a detailed capacity analysis of existing interceptor and sewers 4 Identify deficiencies 5 Define any improvements required to eliminate deficiencies 6 Determine when improvements are necessary 7 Prepare report

CIP No. 3 – Lift Station Nos. 14 & 18 Upgrade

Lift Station Nos. 14 and 18 consistently require maintenance at a much higher frequency than other wastewater facilities operated by the City, averaging two service calls per week vs. one every three months. Lift Station No. 14 is located just north of Hicks Lake on Diamond Loop SE, and Lift Station No. 18 is located west of College St. along the Yelm Highway. These are two of the highest-volume lift stations operated by the City, but they are of an older vacuum-prime type that is prone to clogging and failure, demanding frequent maintenance that is a costly drain on City crew time.

CIP No. 3 will upgrade these two lift stations so their maintenance needs are reduced. Upgrading will include pump replacement with submersible pumps, and may include wetwell modifications in terms of sizing and storage volume.

A consultant will be utilized to assist in determining the most cost-effective solutions, and in preparing a design report, construction plans and specifications.

NOTE: Construction may occur in the 2007 budget year.


CIP No. 4 – Lift Station Nos. 8, 11 & 12 Control Cabinet Replacement

Lift Station No. 8 is located at College Street SE and 6th Ave. SE, Lift Station No. 11 is located just east of Carpenter rd. at Glen Court SE, and Lift Station No. 12 is located just east of Lift Station No. 11 on 5th Court SE. Lift Station No. 8 was brought on-line in 1978, Nos. 11 and 12 came on-line in 1980. After 25 years of service, they have many components that are in need of replacement. The electrical control panels, in particular, are outdated and inadequate. Replacement of the electrical control panels is critical to prevent potential failure and to bring them up to the City’s current standards. Lift station failure could lead to sewer overflows and resulting environment impacts.

CIP No 8 will upgrade these three lift stations with new City-standard electrical control panels. The old wiring will be removed, and the system rewired and updated, including weatherproof cabinets having the appropriate NEMA rating.

CIP No. 5 – Pacific Ave. Sewer & Lift Station No. 21 – Convert Force Main to Gravity

CIP No. 5 involves the conversion of a sanitary sewer main from force main to gravity, and the potential decommissioning of Lift Station No. 21.

Background: Lift Station No. 21 is located along Pacific Ave. just west of College St., and pumps into a 12-inch sewer line in Pacific Ave. So did former Lift Station No. 1, which was located at Lacey Blvd and Clearbrook St. (which was abandoned during the Pacific Avenue/Lacey Boulevard couplet project).

The sewer line in Pacific Ave. was originally designed for a dual-purpose: when Lift Station No. 1 was pumping, the line in Pacific Ave. would act as a force main, flowing west to a high point at golf Club Rd., west of Lift Station No. 21. When Lift Station No. 1 pumps were off, flow would be by gravity in the opposite direction (east) to the Lift Station No. 1 wetwell. Lift Station No. 21 would pump wastewater into the main under either condition, so it was designed to be able to pump into the sewer main even under force main (higher head) conditions.

Current Situation: With Lift Station No. 1 abandoned, the main in Pacific acts as a gravity line only. This presents two problems:

• Without the scouring effect of pumped flow, the sewer main is subject to sludge build up.

• Since it was acting as a force main, the sewer is continuous through all of the manholes between Lift Station No. 1 and the high point. Because those manholes have pipe rather than formed channels, city maintenance crews cannot access the sewer main for flushing or monitoring at more than a dozen manholes along Pacific Ave. between Clearbrook Rd and Golf Club Rd. – a distance of


approximately 5,000 feet. In addition, the pumping ability of Lift Station No. 21 is now outmoded, and potentially unnecessary if its flows can be conveyed to the Pacific Ave. sewer main via gravity.

The goal of CIP No. 5 is twofold:

1. Convert the affected manholes to gravity sewer manholes by cutting away the pipe within each structure and channelinzing through it, and

2. Conduct an engineering study to determine the feasibility of either decommissioning Lift Station No. 21 or conveying its wastewater flows via gravity into the Pacific Ave. sewer main, or modifying the pumping system so it operates more efficiently. CIP No. 6 – Draham Rd. NE Lift Station Preliminary Design Report

A regional lift station will be required to provide service to growth in the Hawks Prairie area north of I-5 in the vicinity of Carpenter Rd. Preliminary studies conducted during development of the 2005 Plan Update place the station just off Draham Rd. NE, just west of Carpenter Rd. NE. The required capacity of the station is projected to be as follows: 915 gpm for year 2010; 1,400 gpm for year 2024; and 3,320 gpm for build out.

A force main approximately 2,850 in length will be required as shown in Figure 8-4. Anticipated force main sizes are 6”, 10” and 12” for 2010, 2024 and build out conditions, respectively. Approximately 2,500 LF of 12” gravity sewer will be required to convey anticipated wastewater flows through the year 2024. Build out conditions will require 15” and 18” sewers. Directional drilling or a tunnel may be required to convey wastewater flows from Britton Parkway to the east.


Figure 8-4 Draham Rd. NE Lift Station

Activities conducted as part of CIP No. 6 will include the preparation of a preliminary design report. The report should be sufficiently complete so that plans and specifications for the Draham Rd. Lift Station, force main and gravity sewers can be developed from it. CIP No. 6 may include, but will not necessarily be limited to the tasks listed below.


Table 8.4 CIP No. 6

Draham Rd. NE Lift Station Preliminary Design Report Tasks

Task Title 1 Evaluate proposed and alternative lift station sites. Identify the

advantages and disadvantages of each site. Select a preferred site. 2 Refine estimated wastewater flows 3 Define and size alternative lift station facilities including station type,

pumps, wetwell volume, etc. 4 Conduct geotechnical investigation and define design criteria for lift

station excavation and foundation support 5 Provide an estimate of the project and O&M costs of each alternative 6 Select a preferred alternative 7 Evaluate the feasibility of attaching the proposed force main to the

existing Carpenter Rd bridge over Interstate 5. 8 Evaluate tunnel drilling vs. directional drilling to convey future gravity

sewer flows from Britton Parkway to the east. Provide estimates for each alternative and select a preferred alternative.

9 Prepare a preliminary design of the preferred alternative 10 Provide a list of environmental and construction permits that will be

required. 11 Provide a schedule for permitting, design and construction 12 Prepare preliminary design report

Construction costs for the Draham Rd NE Lift Station is estimated to range from $750,000 to $1,250,000


CIP No. 7 – Lift Station No. 9 Upgrade Preliminary Design Report

There are currently three 1,000 gpm Flygt submersible pumps in operation in LS 9. The station serves the southeastern portion of the UGA and discharges into the Ruddell Rd. interceptor. Lift Stations 18 and 22 each discharge into gravity lines that convey wastewater to LS 9. LS 37, which is currently under construction, will discharge to LS 9 as well. The location of LS 9 is shown in Figure 8-5 below.

Figure 8-5 Lift Station No. 9 Pump Upgrade

At this time the station is capable of handling existing flows with one pump on. However in the near future, when LS 37 comes on line to serve the Horizon Point development and growth in LS 18 and LS 22 service areas increase the flows to LS 9, the station may require upgrading to increase its pumping capacity. Work associated with CIP No. 7 may include, but will not necessarily be limited to the following tasks:


Table 8.5 CIP No. 7

Lift Station No. 9 Upgrade Preliminary Design Report Tasks

Task Title 1 Evaluate capacity of existing lift station 2 Use future wastewater flow as defined in CIP No. 2 3 Evaluate lift station and determine improvements required to convey

future flows 4 Review capacity of piping downstream of LS 9 and improvements as

defined in CIP No. 2 5 Prepare system curves, make equipment selections, and provide design

basis and sizing calculations. 6 Prepare preliminary design report


CIP No. 8 – Mullen Road Force Main

The City anticipates constructing major improvements to Mullen Rd. SE in the next three to four years. CIP No. 8 will include the construction of approximately 3,500 LF of 4” force main piping, which will be installed as part of the street improvement project. The City desires to construct this segment of the proposed Lift Station AE force main as part of the street improvement project in order to avoid damaging the reconstructed roadway at a later date.

The force main will connect to the existing 18” Ruddell Rd. interceptor at or near existing manhole No. SBR01, located at the intersection of Ruddell Rd. SE and Mullen Rd SE, as shown in Figure 8-6. The eastern end of the force main will terminate at the City’s boundary with Thurston County, located at or near the eastern property line of tax lot #11834230100, owned by School District #3.

Figure 8-6 Mullen Road Force Main


The 4” force main will be installed as a dry pipe until Lift Station AE, located near Pattison Lake, and the remainder of its associated force main is constructed. Work associated with CIP No. 8 may include, but will not necessarily be limited to the following tasks:

Table 8.6 CIP No. 8

Mullen Road Force Main Tasks

Task Title 1 Conduct preliminary route study and select route for force main 2 Prepare construction plans and specifications for approximately 3,500

LF of 4-inch force main 3 Construct force main as part of Mullen Rd. Improvement project


CIP No. 9 – Permanent Flow Monitoring Program

CIP No. 9 will develop and implement a permanent flow monitoring program that will allow City staff to observe and record wastewater flow data at selected locations throughout the system.

For the flow monitoring program to be successful and to ensure that useful and accurate flow data is collected on a consistent basis, it is essential that the City provide the adequate resources to operate and maintain the flow meters and manage flow data once the program is in place. An annual budget should be set aside to cover the ongoing costs of labor and equipment maintenance. Labor costs will include work associated with site visits, data acquisition, maintaining equipment and data management.

Work associated with CIP No. 9 may include, but will not necessarily be limited to the following tasks:

Table 8.7 CIP No. 9

Permanent Flow Monitoring Program Tasks

Task Title 1 Develop and define the flow monitoring program 2 Define permanent flow measurement locations 3 Determine preferred type and style of system elements such as:

• portable vs. non portable meters • Use of primary device vs. in situ depth and velocity • construct meter manholes vs. measure in existing manholes • Define communication protocols i.e. SCADA, RF, wireless,

hardwire telephone, etc 4 Prepare cost estimate 5 Prepare report defining alternatives evaluated and preferred monitoring

system type and equipment 6 Equipment acquisition 7 Develop an annual estimate of costs for continued maintenance,

equipment repair and data management. 8 1st year data acquisition and data management


8.3 SIX-YEAR CIP COST ESTIMATE

The estimated cost of the six projects included in the Six Year Capital Improvement Plan is shown in Table 8.8. It is recommended that the City implement CIP No. 1 prior to or concurrent with implementing CIP No. 2, and so on.

Table 8.8

6-Year Capital Improvement Plan Costs Through Year 2010

Identifier Title Estimated Cost* CIP No. 1 STEP Force Main Analysis $ 60,000 CIP No. 2 Ruddell Rd. Interceptor Study $ 60,000 CIP No. 3 Lift Station Nos. 14 & 18 Upgrade $ 440,000 CIP No. 4 Lift Station Nos. 8, 11 & 12

Control Cabinet Replacement $ 60,000

CIP No. 5 Pacific Ave. Sewer & Lift Station No. 21 – Convert Force Main to Gravity

$ 200,000

CIP No. 6 Draham Rd. NE Lift Station Preliminary Design Report

$ 100,000**

CIP No. 7 Lift Station No. 9 Upgrade Preliminary Design Report

$ 40,000

CIP No. 8 Mullen Rd. SE Force Main*** $ 143,000 CIP No. 9 Flow Monitoring Program $ 110,000

* Costs in 2005 dollars ** Estimated cost is for design report. Design and construction costs for the Draham Rd. NE Lift Station is estimated to range from $750,000 to $1,250,000 ***Estimate based on spreadsheet located in Appendix D

8.4 IMPROVEMENTS REQUIRED TO SERVE FUTURE GROWTH WITHIN THE UGA

As discussed in the Introduction to this chapter, improvements to the existing interceptor system will be necessary to meet anticipated growth in the UGA. Wastewater flows for each study year were represented in the hydraulic models as a function of increasing residential and commercial populations, septic to sewer conversions, and I/I as defined in Table 7.2.

The types of improvements that will be required to meet the demands of future growth will include the following: City of Lacey 2005 Wastewater Comprehensive Plan Update \\7348101\Chapter 8.doc 8-18

• The capacity of existing pipes will be increased either by replacement with larger capacity pipes or by constructing parallel pipe systems

• Construction of new interceptors

• Construction of new local sewers

• Capacity upgrades to existing lift stations

• Construction of new lift stations and force mains

These improvements, with the exception of local sewer improvements are shown in Figure 8-1. Note that many of the improvements shown are not included in the Six Year Capital Improvement Program. These are presented as an aid to Lacey staff and to proponents of future development proposals to assist in identifying the approximate size, location and scope of major facilities that may be required to serve future growth areas within the UGA.

The gravity sewer and force main sizes shown in Figure 8-1 indicate the pipe sizes required to serve the population anticipated during each study year as defined in the models. Note that in some cases, different pipe diameters are indicated for 2010, 2024 and build out conditions. These values indicate the pipe diameters that are required to adequately convey the peak hour wastewater flows predicted by the models for each study year. Although different diameters may be required for each year, it is recommended that facilities be sized to convey the larger year 2024 flows, rather than 2010 flows. This will eliminate, or at least minimize the need to upsize relatively new facilities again in the near future. For major facilities, it may be beneficial to construct facilities based on build out sizes. The timing for when the improvements are required was defined in the models as a function of population growth defined in TRPC’s traffic analysis zones. However in reality, the facilities will be needed as development actually occurs. Actual population growth could vary substantially from the TRPC predictions. Pipeline improvements not included in the Six Year Capital Improvement Plan

Below is a brief description of the improvements that are not included in the Six Year Capital Improvement Plan, but will likely be required to serve the anticipated growth areas of the UGA. They are presented in geographical order, generally from south to north and are not intended to be listed in any order of priority. A summary of the projects is presented in Table 8.9 following the descriptions.

55th Way SE


By 2010 portions of the existing 10-inch gravity sewer in 55th Way SE will be reaching capacity. By the year 2024 upsizing to 12-inch diameter will be required.

Mullen Rd. SE System

Year 2024 wastewater generated in the southeastern portion of the UGA will be conveyed via a series of two new lift stations, approximately 7,500 LF of new 4-inch force main and 7,800 LF of new10-inch gravity sewer constructed along the Mullen Rd. SE corridor. Approximately 3,500 LF at the western end of the force main discharging LS_AE flows will be constructed as part of CIP No. 8.

Marvin Rd. SE System

Year 2024 wastewater generated in the southeastern portion of the UGA north of Mullen Rd. SE will be conveyed via a series of two new lift stations, approximately 4,200 LF of new 4-inch force main and 7,500 LF of new 8- and 10-inch gravity sewers constructed along the Marvin Rd. SE corridor. A significant portion of the wastewater generated in the build out scenario is produced from septic to sewer conversions.

BNRR Right-of-Way System

Year 2024 wastewater generated in the Marvin Rd. SE System will be conveyed to the BNRR system. Flows from the Carpenter Rd. SE System will also enter the BNRR system at future Lift Station LS_MV and then pumped to the existing collection system through approximately 4,000 LF of new 4-inch force main. Approximately 7,000 LF of new 10- and 15-inch gravity sewers constructed along the BNRR right-of-way will be required.

Carpenter Rd. SE System

Year 2024 wastewater generated in the south central portion of the UGA will be conveyed via a series of two new lift stations, approximately 3,800 LF of new 4-inch force main and 6,900 LF of new 8-inch gravity sewers constructed along the Carpenter Rd. SE corridor. A significant portion of the wastewater generated in the build out scenario is produced from septic to sewer conversions.

Steilacoom Rd. SE Interceptor

Year 2024 wastewater generated in the eastern portion of the UGA will be conveyed via the Steilacoom Rd interceptor to Lift Station 12. The gravity sewer will be approximately 9,000 LF of new 10- and 12-inch gravity sewers constructed along the Steilacoom Rd. SE and Kinwood St. SE corridors. The wastewater generated in the build out scenario is produced from both new development and from septic to sewer conversions.

Lift Station 12 Force Main Reroute City of Lacey 2005 Wastewater Comprehensive Plan Update \\7348101\Chapter 8.doc 8-20

Growth and sewer to septic conversions in portions of the Meadows and Tanglewilde Place planning areas will require the construction of a new interceptor sewer along the Steilacoom Rd SE corridor discussed above. It is anticipated that the interceptor will discharge into LS 12. Model simulations predict that LS 12 is currently operating under capacity during peak hour flow; however interviews with Lacey staff indicate that the model may be over-predicting existing flows entering the station. Maintenance staff has observed that the station now regularly operates at capacity. Therefore additional flows directed to the station from the future Steilacoom Rd SE interceptor will require that the station be upgraded.

LS 12 currently discharges wastewater to the west into an 8-inch PVC sewer located in 5th Way SE, which subsequently discharges into LS 10 on Carpenter Rd. SE. Increasing the discharge rate at LS 12 would require that approximately 1,800 LF of the existing 8-inch gravity line and LS 10 be upgraded to convey the increased flow.

These two upgrades can be avoided if the LS 12 force main is rerouted to the east and then north along SE Kinwood St., and then discharged into the 15-inch Martin Way trunk near the intersection of Martin Way E and SE Kinwood St. Each of the future modeling scenarios were based upon the assumption that the force main will be redirected to Martin Way E. All lift station capacities and proposed pipe sizes are based using this assumption.

When new development occurs and/or septic to sewer conversions take place triggering the need for the Steilacoom Rd SE interceptor, LS 12 should be upgraded and the force main rerouted.

Husky Way SE Trunk

Most of the developed properties in the Thompson/Tanglewilde Place planning area north of Steilacoom Rd. SE are currently served by on-site septic systems. The 2005 Plan Update assumes that at some point, most likely after the year 2024, many or perhaps all of those systems will be converted to conventional gravity sewers. A new gravity sewer constructed along the Husky Way SE corridor will serve as the main feeder trunk line to which other local neighborhood sewers can connect.

The Husky Way trunk was not modeled, but a review of existing surface contours suggests that 8-inch to 10-inch sewers will likely provide the required capacity to serve this area. The Husky Way trunk will connect to the existing system at or near manhole SXR01 located west of Kinwood St. SE on SE 3rd Way.


Hawks Prairie System

Year 2024 wastewater generated in the northwest area of the UGA north of Interstate 5 in the vicinity of Carpenter Rd. NE will be conveyed via a series of three new lift stations, approximately 12,000 LF of new 4-inch force main and 10,500 LF of new 8- 10-, and 12-inch gravity sewers.

Most of the Hawks Prairie system will serve new development, although there are some developed areas currently using septic systems that will ultimately convert to sewer service.

The Draham Rd. Lift Station is one of the proposed lift stations in the Hawks Prairie system. It will become a regional pumping facility for the City. A preliminary design of the proposed lift station is incorporated in CIP No. 6. The Draham Rd. Lift Station is identified in the hydraulic models as LS_BD. There is some urgency in getting this facility constructed. The immediate need for the station is to serve commercial development that is expected to occur within the next few years along Britton Pkwy. NE.

Table 8.9

Summary of Recommended Improvements Not Included in the Six Year Capital Improvement Plan

Improvement Gravity Sewer Lift Station Force Main

55th Way SE Yes Mullen Rd. SE System

Yes Yes Yes

Marvin Rd. SE System

Yes Yes Yes

BNRR Right-of-Way System

Yes Yes Yes

Carpenter Rd. SE System

Yes Yes Yes

Steilacoom Rd. SE Interceptor

Yes

Lift Station 12 Force Main Reroute

Yes

Husky Way SE Trunk

Yes

Hawks Prairie System

Yes Yes Yes


8.5 LIFT STATIONS

Nearly all of the wastewater that will be generated as a result of future growth will be pumped through one or more lift stations. As a result, upgrading existing lift stations and the construction of new pumping facilities will play a major role in providing wastewater service to Lacey’s future growth areas.

In addition to the existing lift stations that were included in the models, ten future lift stations were modeled and their required capacities determined. The locations of the modeled lift stations are shown on Figure 8-1. Each station’s anticipated capacity for years 2010, 2024 and build out is summarized in Table 8.10. Each future lift station site was selected based on its proximity to proposed interceptor sewers and topography. Each site was visited and appears to be suitable for the construction of pumping facilities; however property acquisition, geotechnical, environmental, permitting and other constraints were not evaluated.


Table 8.10 Modeled Lift Stations

Peak Hour Flow Capacity Summary

Modeled Inflow (gpm) Capacity Capacity status

Required Capacity

(gpm)Capacity status

by 2010

Required Capacity


by 2024

Required Capacity


by Built-Out Comment

3 LS19 190 340 ok 573 Additional

Capacity Req'd 647 Additional

Capacity Req'd 2,841 Additional

Capacity Req'd See note8 LS23 14 180 ok 22 ok 23 ok 83 ok

10 LS14 153 175 ok 183 At or near Capacity 220

Additional Capacity Req'd 706

Additional Capacity Req'd See note

82 LS3 543 1,100 ok 625 ok 683 ok 1,306 Additional

Capacity Req'd

314 LS9 1,209 1,285 ok 1,741 Additional



Capacity Req'd See note515 LOTT Martin Way 4,023 8,328 8,510 11,941 35,648 See note

613 LS10 80 400 ok 110 ok 143 ok 690 Additional

Capacity Req'd See note


Capacity Req'd

860 LS22 170 183 ok 212 At or near Capacity 231




Capacity Req'd910 LS21(not modeled) - 300 ok - ok - ok - ok


Capacity Req'd920 LS2 62 140 ok 71 ok 78 ok 107 ok

2886 (future) LS_BF ------- ------- ------- 83 ------- 332 ------- 906 -------2889 (future) LS_BH ------- ------- ------- 95 ------- 237 ------- 751 -------

2904 LS12 200 100 At or near Capacity 383


Additional Capacity Req'd 1,738


2913 (future) LS_MV ------- ------- ------- 488 ------- 1,254 ------- 4,826 -------2916 (future) LS_AW ------- ------- ------- 334 ------- 816 ------- 3,452 -------2921 (future) LS_MR ------- ------- ------- 156 ------- 504 ------- 2,655 -------2927 (future) LS_CR ------- ------- ------- 51 ------- 144 ------- 556 -------

2940

(future) Draham Rd (model

name=LS_BD) ------- ------- ------- 915 ------- 1,403 ------- 3,318 -------2964 (future) LS_AJ ------- ------- ------- 156 ------- 504 ------- 1,433 -------2968 (future) LS_AE ------- ------- ------- 215 ------- 682 ------- 2,067 -------3986 (future) LS_BS ------- ------- ------- 29 ------- 88 ------- 307 -------

NOTES* "G_ID" = Hydraulic model identification number

LS19 Triplex station; 2 pumps currently installed, room for a 3rd pump availableLS14 Capacity increase is required assuming that existing septic systems are converted to conventional sewersLS9 Triplex station; 3 pumps currently installed, pump upgrade included as part of 6-yr CIP

Martin Wy LS owned and operated by LOTT. Future capacities shown were projected by hydraulic modelingLS10 Assumes that LS 12 force main is rerouted to discharge into the Martin Way trunkLS22 Future development proponents will upgradeLS12 Station operating at capacity; currently disch to LS 10; Recommend FM reroute to Martin Wy Trunk. Capac increase req'd due to septic to sewer conversions

*Model G_ID Lift Station

Built-Out scenario2024 scenario2010 scenarioExisting Condition


8.6 IMPACT OF LOTT RECLAIMED WATER SATELLITE PLANTS As described earlier in Section 3.10, Lacey is participating in a long-range Wastewater Resource Management Plan (WRM Plan) with Olympia, Tumwater and LOTT. The WRM Plan calls for future reclaimed water treatment capacity to be constructed in small increments, in the form of small satellite treatment plants. LOTT’s satellite Class A reclaimed water plant, the Hawks Prairie plant, is currently under construction at 6121 East Martin Way. The facility will be on-line by no later than fall 2006. LOTT plans to initially utilize one membrane filtration unit and have the second filtration unit on-line by 2007. With both filtration units, the treatment facility can produce a maximum of 2.0 MGD. Of the 2.0 MGD, LOTT requires 0.25 MGD for the wetland on Hogum Bay, Olympia has the rights to 0.30 MGD of the first membrane unit, and Lacey has the rights to 1.45 MGD from both membrane units. LOTT is in the process of acquiring a permit for the Martin Way Class A Reclaimed Water Facility. Lacey will not require a separate permit for the reclaimed water distribution system and will be covered under LOTT’s permit by an agreement with LOTT. A specific reclaimed water supply agreement between LOTT, Thurston County, and Cities of Lacey, Olympia, and Tumwater for the Martin Way facility is in the process. The Hawks Prairie plant is configured in such a way that when the plant comes on-line there will be no reduction or increase in Lacey’s wastewater collection system flows. Therefore, the recommendations outlined in the 2005 Plan Update should not be affected by operation of the plant. The WRM Plan also calls for construction of the Chambers Prairie satellite plant located in the southwestern portion of the UGA in the Horizons planning area. The plant may be located in the vicinity of LS 9. If the Chambers Prairie plant is constructed it may cause a reduction of flows discharged from LS 9 and in wastewater conveyed through the Ruddell Rd. interceptor. However, plans for the plant are in the very early stages of development and the current timeline calls for construction of the reclaimed water plant in about twenty years. There are many factors both within the City’s control and out of the City’s control that will determine when or even if the Horizons plant will be constructed. The City should remain in regular communication with LOTT so that future plans regarding the plant are well understood. At this time it is recommended that the City implement the improvements scheduled for the next six-year planning period without regard to the Chambers Prairie plant. Future wastewater comprehensive planning efforts conducted by the City however should carefully investigate LOTT’s plans regarding the plant and determine what effects, if any, construction of the plant will have on Lacey’s collection system.

City of Lacey 2005 Wastewater Comprehensive Plan Update \\7348101\Chapter 8.doc

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chapter 8 capital improvement program - ci.lacey.wa.us...feasibility, advantages and disadvantages...

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