Chapter 10 Capital Facilities Plan

Both operations and maintenance and capital facility planning are fundamental to the infrastructure-dependent Wastewater Utility. The lift stations, pipes, manholes and STEP systems that make up the wastewater infrastructure vary in age, materials and structural integrity. At some point in its life, infrastructure is best replaced or upgraded through the capital facilities planning process.

Ongoing work to systematically televise and evaluate the condition of the individual pipes helps prioritize repair and replacement needs. As needed, pipes can be repaired or replaced by City crews, or for more involved work, by contractors. Contractor work is typically funded through the City’s Capital Facilities Plan (CFP). Pipe capacity upgrades, lift stations rehabilitations, and conversion of onsite sewage systems to public sewer are also included in the CFP. These work efforts will continue in the years to come.

The projects contained in the CFP are funded annually through Wastewater Utility rates and General Facilities Charges (GFCs). We pursue bonds and Washington State-managed low interest loan and grant programs when needed and available. Chapter 11 details a financial strategy involving a combination of cash and debt financing of capital projects.

This chapter discusses programs and systems that characterize the condition of existing infrastructure, identify infrastructure deficiencies and prioritize capital projects for both a six and a 20-year planning horizon. The prioritized projects for both six and 20 years are summarized at the end of this chapter in the basic format of the CFP.

10.1 Physical Condition of the Gravity Sewer Collection System

Assessing the condition of existing infrastructure is a necessary component of effective asset management and capital planning. The vast majority of the wastewater collection system consists of gravity sewer mains and manholes. Sewer mains are televised using remote tractor-mounted cameras that travel through pipes and send video images to above-ground personnel. The videotapes are stored and evaluated at a later date.

The condition of gravity sewer pipes is assessed using the Pipeline Assessment and Certification Program (PACP) developed by the National Association of Sewer Service Companies (NASSCO) and accepted as an industry standard. We store and manage sewer pipeline videotapes and descriptive data using Granite XP software.

The condition of gravity sewer pipes is assessed on an ongoing basis, using the following criteria:

• Pipeline integrity (physical structure, slope and alignment).

• Inflow and infiltration (inflow of stormwater from catch basins and roof drains, and infiltration of groundwater through pipe and manhole leaks).

• Operating efficiency (extent to which the system operates as designed with minimal input of energy or operation and maintenance).

• Potential for illicit cross connections (discharges to stormwater pipes and surface waters)

• Risk and vulnerability (effect of potential failure on public or environmental health).

We began our ongoing condition assessment work in July 2005. In 2006, we estimated it would take six years to complete an initial detailed assessment of the 185 miles of gravity collection pipes. As of June 2013, we completed video inspections of approximately 92% of the gravity collection system, including all of the highest risk and most time consuming pipes.

In partnership with LOTT, computerized flow monitors are installed in key pipes in order to track flows over time. The data provides information on wastewater flows as well as inflow and infiltration and operating efficiency. Lift stations are monitored continuously through the Utility’s supervisory control and data acquisition (SCADA) system.

The general characteristics of the wastewater pipes are summarized as follows.

Pipeline Integrity

Due to the full implementation of PACP-based video pipe inspections in the last 6 years, the structural integrity of our sewer pipe network is now well-understood. Approximately 30 percent of the sewer gravity pipes were installed prior to 1960 and are near or past their 50-year design life. The likelihood of leaks due to settlement, deterioration, sediment accumulation and root intrusion may increase exponentially in these pipes. Another 20 percent of the pipe system was installed between 1960 and 1975.

Because concrete and asbestos cement pipes were still widely used during this period, the pipes are susceptible to corrosion and deterioration from hydrogen sulfide gas, such as that produced by STEP systems. Several acute corrosion problems related to STEP systems were discovered in early 2006 and addressed with manhole and concrete pipe liner projects. Several additional projects to address corrosion are needed and are included in this Plan.

Televising and condition rating of all sewer pipes should be complete in mid-2014. Our work to date indicates the following:

• 77% of the pipes are in good condition

• 9% are in fair condition

• 6% are in poor condition

• 8% remain to be inspected. Many of these pipes are relatively new and are assumed to be in good condition.

These data suggest that the gravity sewer system is in manageably good condition. Repairs can be completed proactively in order to avoid costly and/or extensive emergency repairs. Often times, repairs are needed to only a small section of the pipe. Repairs to problematic pipes are completed by in-house or contractor crews. With planning, cost-effective trenchless repair technology is the preferred choice for repairs. With this technology, an epoxy impregnated sock is pulled through the faulty pipe, expanded to meet the sides of the pipe and cured in-place. The pipe is repaired at a fraction of the cost of pipe excavation and subsequent street reconstruction.

The pipe televising and condition rating program indicates that needed pipe replacements and repairs can be addressed proactively and at manageable costs.

Pipe inspections and condition rating are a key work element of the Utility. Operations and maintenance crews in concert with engineering staff provide dedicated resources for pipe cleaning and inspection.

Inflow and Infiltration

Inflow and infiltration (I&I) mainly occurs in combined storm/sanitary sewers in the downtown, South Capitol neighborhood and portions of northeast and west Olympia and in older faulty pipes. Inflow is precipitation that enters sewer pipe from catch basins within the roadway and roof downspouts. Infiltration results from groundwater entering sewer pipes through cracks, bad joints, or leaky manholes. These inputs of storm and groundwater can result in significant excess flows and surcharging of the pipes during the wet season. On rare occasions, surcharges during large storms can extend above the manhole rim with wastewater discharging to the street.

The Wastewater Utility reduced I&I in the 1990s through several extensive pipe replacement projects in West Olympia. The work was undertaken as part of an agreement with LOTT that addressed wet season flow reduction.

Currently, flow monitoring at most of our lift stations tracks seasonal variations in pipe flows. High wet weather flows are typically adequately-managed by the LOTT treatment facility. In the future, wet weather flows due to infiltration may decrease as pipes and manholes are rehabilitated through the condition rating program. Additionally, combined pipes responsible for inflow are separated as feasible and cost effective. Inflow and infiltration are adequately managed by the Wastewater Utility.

Operating Efficiency

Older areas of the City with smaller diameter pipe, separated joints and other challenges can require more frequent maintenance, particularly pipe cleaning and root control. These areas are identified through periodic review of the work order system and the scheduled maintenance program. In recent years, high frequency maintenance has consumed approximately 5% of operation and maintenance resources on an annual basis.

On a case-by-case basis, the cost of increased maintenance needs is compared to reconstruction. For example, one well-known high maintenance area-the South Capitol neighborhood-is being adequately served by careful flow evaluation, extra maintenance, and isolated, small-scale rehabilitation projects. This highly managed approach to capacity limitations is cost effective, given the high costs of extensive reconstruction. Other localized areas of high maintenance in Olympia are best served, however, by reconstruction. Depending upon the scale of the work effort, construction projects are completed in-house or by contractors through capital facilities funding. With the exception of lift station upgrades, current capital facilities’ planning does not include projects targeting operating inefficiencies.

Grease accumulation in sewer pipes, primarily from food service establishments, is also a maintenance problem. Unnecessary clogging of pipes reduces operating capacity and can result in sewer overflows. Proper restaurant procedures for managing fats, oils and grease (FOG) onsite can prevent this problem. LOTT and the City provide educational materials to restaurant owners and issue citations for grease containment violations. A more rigorous program to enforce grease abatement, including the enforcement of existing pretreatment regulations in OMC 13.20, is scheduled for implementation within the next several years.

Illicit Cross Connections

The Wastewater Utility partners with the City Storm and Surface Water Utility to actively inspect their pipe systems for unintentional cross-connections. Improperly constructed pipes and manholes can result in ongoing discharges of wastewater to the stormwater pipe systems. In recent years, our inspections have discovered one or two of these cross connections a year, especially in older areas of the City.

The respective wastewater and stormwater systems have been inspected for design features that are correlated with cross-connections such as pipes in close proximity to each other, unclear construction blueprints, and sewer pipes passing through stormwater pipes. Potential problem areas have been field investigated. Other areas that may be susceptible to an unintentional cross-connection during future construction have been flagged on utility maps. These work efforts and the coordination between Wastewater and Stormwater will continue.

Risk

Structural failures in wastewater pipes can result in sewer overflows impacting public and environmental health. Our evaluation of the sewer pipe network has focused on improving older pipes susceptible to problems. Additionally, ensuring the non-stop operation of lift stations is a program priority (see below).

Given the current knowledge of pipe and lift station condition, the risk of infrastructure failure is modest. High risk infrastructure is well-managed. Systems in close proximity to surface waters are prioritized. However, the extensive scale of the wastewater system suggests that failures will occur. Utility staff plans for emergency response to failures thereby minimizing impacts.

Summary of Sewer Pipe Condition

Overall, the Wastewater pipe network is well-understood and in manageable condition. Future work can focus on proactive maintenance and timely repairs. Results suggest the need for ongoing scheduled repairs, but not catastrophic failure or unanticipated expenditures. Operation and maintenance resources may need to be augmented as the City grows and the infrastructure continues to age.

10.2 Capacity Analysis of the Gravity Sewer Collection System

Capacity analysis is used to identify improvements needed in existing infrastructure to increase capacity for planned or proposed development(s), as well as to plan for extending sewer into unsewered areas. Capacity improvements in the gravity sewer system may be needed for several reasons:

• New development "upstream" may increase demand on existing "downstream" pipes and pumps.

• New development may require extending the system to additional areas.

• Pipes may have been under-designed or may receive excess flows due to stormwater inflow and groundwater infiltration.

In 2006, a computer model was used to estimate wastewater flows, based on the current and projected population, land use and water entering the system from inflow and infiltration (I&I). The model results were compared to the capacity of existing pipes and pump stations. The model identified areas of the system currently over capacity or projected to be over capacity within a 20-year time frame. The model inputs and outputs were re-evaluated in 2012. The model remains a valid tool for this planning effort.

Flow calculations and the associated computer simulations were calibrated based on actual data collected at the LOTT Budd Inlet Wastewater Treatment Plant and 23 flow monitoring locations spread throughout the LOTT service area. The sewer model was designed to simulate a 10-year peak hour storm event. See Appendix C-1 of the 2007 Wastewater Plan for a description of the model and methodology used.

While the computer model mainly focused on pipes larger than eight inches in diameter, it included many of the City’s eight-inch pipes located in key areas, or areas deemed critical by City staff. The model incorporated 20 lift stations, including two LOTT stations and 18 of the City’s stations.

For purposes of determining capacity limitations, three criteria were defined:

• Depth to flooding - the height from the maximum water surface elevation to the manhole cover.

• Pipe surcharge ratio - the ratio of the maximum modeled hydraulic grade to the pipe diameter (surcharge ratio of 1.0 indicates the pipe is completely full).

• Percent capacity - the projected flow through the pipe, divided by the full pipe flow capacity.

Capacity Limitations

The model helps us understand potential capacity limitations that might occur within the 20-year planning horizon. Population growth is anticipated to occur as projected in the 2007 Plan. Since growth and population projections in the years 2007-2012 did not meet previous expectations, the model results may be conservative and overestimate flows. The validity of the 2006 model is supported modest growth.

The model simulations identified several existing and future capacity limitations in the gravity collection system, as summarized below and shown on the maps in Figures 10.1 and 10.2. Some of these have already been addressed.

View Figure 10.1 Modeled Capacity Limitations for 2007 - 2010

View Figure 10.2 Projected Capacity Limitations for 2025

Existing capacity limitations were identified in six locations as shown in Figure 10.1. Model runs for the next several years showed no additional developing limitations. The six locations are described below:

1. West Bay Road near Harrison Avenue. Flow limitations were corrected as part of the 2007 Wastewater Plan implementation.

2. Downtown Olympia. The identified problem addresses modeling uncertainties in downtown Olympia. Flow in the complex downtown Olympia portion of the system is largely unknown. Much of this system is comprised of combined sewers, and many of these sewers have not been the subject of detailed flow monitoring studies. Because of the high amount of inflow associated with the combined system, coupled with the age of many downtown pipes, targeted flow monitoring began in August 2006. The recent monitoring did not identify flow capacity concerns, though some level of uncertainty remains. Sewer overflows in downtown have not been observed in recent years.

3. 4th Avenue. Capacity upgrades at the east side of the 4th Avenue Bridge have been completed as part of the 2007 Wastewater Plan implementation.

4. Capitol Blvd/Henderson Blvd/Railroad Interceptor. LOTT has completed needed improvements.

5. Division-Jackson Lift Station tributary area. Several projects increasing the capacity of the lift station pumps, as well as targeted pipe repairs, have significantly reduced the risk of surcharging.

6. Kaiser Road Lift Station Tributary Area. The sewer pipes upstream of many of the lift stations, including the LOTT Kaiser Road Lift Station, appear surcharged in the simulations. However, the lift stations intentionally use the capacity of upstream sewers to store flow during heavy storm events. These systems operated as designed and do not pose a risk of flooding.

Future capacity limitations for the year 2025 are shown in Figure 10.2. The four new capacity limitations are listed below:

1. LOTT Indian Creek Interceptor. During storm events, this large interceptor pipe is projected to surcharge heavily with several flooded manholes. This limitation is caused by a narrowing of the pipe from 30 to 24 inches in diameter

2. LOTT Martin Way Interceptor. During storm events, this interceptor was projected to surcharge near College Street and Lilly Road. LOTT has connected an overflow bypass pipe thereby reducing the risk of manhole flooding in this area.

3. LOTT Grass Lake Interceptor from Capital Mall Drive to Mottman Road. Under peak hourly storm conditions, this interceptor pipe will surcharge, creating a flow backup at the intersection of Capital Mall Drive and Cooper Point Road. However, because the depth of the interceptor at the confluence is approximately 13 feet, the two or three feet of projected surcharging are not expected to present a risk of manhole flooding.

4. Henderson Boulevard and Boulevard Road. The scenario for 2025 shown in Figure 10.2 assumes that all flows in the Southeast Watershed Basin (Figure 10.3) continue to be routed to the Budd Inlet Treatment Plant via sewers along Henderson Boulevard and Boulevard Road. If this remains true, both of these systems could experience storm-related surcharging in the future. However, the model indicated that the depth of surcharging in both Boulevard Road and Henderson Boulevard systems does not pose a major risk of manhole flooding.

View Figure 10.3 Southeast Watershed Basin

Annual Capacity Analysis

LOTT continues to analyze the capacity of the City’s critical sewer mains using a modified version of the model developed in 2006, and provides annual capacity reports that focus on flows and loadings, I&I and flow monitoring, and capacity assessment. See Appendix N for the 2011 Inflow & Infiltration and Flow Monitoring Report. We review these reports on an annual basis with LOTT as part of shared long range planning efforts.

10.3 Condition Assessment of Lift Stations and Force Mains

The condition of our lift stations and force mains was assessed using the criteria described in Section 10.1 (Integrity, inflow and infiltration, operating efficiency, and risk/vulnerability).

In 2006, seven lift stations were identified as having major physical deficiencies: Black Lake, West Bay, Division & Jackson, Division & Farwell, Miller & Ann, Kempton Downs and Water Street. Projects addressing deficiencies at all seven of these lift stations have either been completed or are currently underway in 2013.

Table 3.2 in Chapter 3 shows the age, type, and upgrade/replacement project date (if applicable) of the 33 lift stations that the City owns and/or manages. A vulnerability assessment of lift stations older than 20 years was completed as part of this plan and is included in Appendix G. Typical problems include aging electrical, mechanical, and performance monitoring systems.

The results of the assessment indicate the need for continued upgrades to older lift stations. Priority lift stations include:

• Miller and Central

• Miller and Ann

• Water Street

• Old Port 2

• Roosevelt and Yew

Upgrades to the identified lift stations consistent with the schedule provided in Table 10.3 are expected to minimize risks for acute or chronic failure.

Of the 8.5 miles of force main pipe, 40 percent are constructed with older materials - concrete or asbestos cement (AC). The remaining 60 percent are constructed with more durable PVC pipe. All the remaining concrete and AC force mains are prioritized and planned for replacement. Untimely failure of these pipes is not anticipated. See Table 10.3.

10.4 Capacity Analysis of Lift Stations and Force Mains

Besides assessing the structural and mechanical integrity of the lift stations and force mains, the stations were evaluated for the adequacy of their capacity by comparing design capacity with measured capacity. The comparison confirmed that there are no current capacity deficiencies.

Future capacity limitations at the following lift stations are governed by growth/build out conditions:

• Cedrona

• Ken Lake

• Miller and Central

• Old Port 1

• Old Port 2

• Rossmoor

The land use build out projections and associated pump limitations assume that the City and UGA are allowed to continue to a maximum reasonable population density of eight residents per acre. Upgrades to these lift stations have been incorporated in long-term capital facility plans (Table 10.3).

10.5 Condition Assessment of the STEP Systems

All STEP systems in Olympia have been installed in the past 25 years and have a life expectancy of at least 40 years. A condition assessment, completed in 2006 and revisited in 2012, showed no structural or condition issues with the STEP pipelines. Since all pipes are made with PVC materials, future problems with pipeline integrity are unlikely. Infiltration is also unlikely, since STEP systems are tightly sealed and pressurized, and installed using new construction techniques.

STEP tanks, however, which are typically constructed of concrete, may over time develop structural issues related to corrosion. Hydrogen sulfide gas produced by STEP effluent is corrosive to concrete. While no active evaluation of the condition of existing tanks has been completed, there have been no documented structural failures of STEP tanks. Still, plans to replace a certain percentage of tanks have been built into this plan’s 20-year planning horizon.

Similarly, effluent STEP pumps have been shown to last 20 or more years, with at most replacement of the "liquid end" (moving parts) part of the pump completed as part of regularly scheduled services. Due to the number of STEP systems installed in the last 20 years, though, it is anticipated that at some point in the 20-year planning horizon these pumps will need to be replaced at a high enough frequency that capital funding will be necessary. In general, STEP systems are currently performing adequately.

Commercial STEP systems requiring considerable City maintenance will continue to be a priority for conversion to gravity sewer service. Projects are prioritized are gravity sewer becomes available at the site. One commercial STEP conversion is anticipated by this Plan.

10.6 Major Sewer Extensions

Major extensions of sewer infrastructure will be needed to service outlying areas of Olympia and its UGA. These projects will be prompted by new development and are therefore anticipated to be completed with private funding. Potential projects include the South Bay Road and the 28th/Cooper Point extensions. These two projects as well as other necessary extensions may be included in future Capital Facility Plans and identified as privately-funded projects.

Several sewer extensions associated with transportation improvements are anticipated within the 20-year planning period of this Plan. One project, the Boulevard Road Roundabout at Morse Merryman, is projected to occur within the next six years. A sewer extension project to extend gravity sewer south on Boulevard Road from near Washington Middle School to the Log Cabin Road Roundabout will be completed as part of this transportation improvement project, and funded by utility funds. These projects are authorized and managed by the Utility through the capital facility program.

10.7 Summary

Based on the Condition and Capacity Assessments completed for the various types of wastewater infrastructure, needed projects are identified for funding in the next 20 years. The projects are summarized in Tables 10.1-4 below utilizing the funding categories currently used in the Capital Facility Plan (CFP).

The list of projects is tentative. It will be evaluated and refined during annual capital facility planning processes. However, it provides a projection of likely projects and their potential funding requirements. Many of the projects are proactive in nature.

Figure 10.4 shows the locations of all but the recurring projects. A discussion of funding of these projects, including whether a project is entirely or partially funded by rates and/or General Facility charges, is included in Chapter 11.

Additional minor projects (system upgrades associated with ongoing asphalt overlays, sewer system planning, and infrastructure planning) are included in the CFP as annual allocations as presented in Tables 10.4 and 10.5.

Table 10.1

Repair and Replacement Projects

No.

Project Name

Description

Cost ($K)

Timing

1

Prioritized Repairs

Major repairs using trenchless technologies

$265

Annual

2

Spot Repairs

Minor open-cut repair work

$100

Annual

3

Manhole Repair and Replacement

Repairs of structural deficiencies and leaks

$100

Every 3 years

4

Commercial STEP Conversions on Yelm Highway

Convert approximately 5 Commercial STEPs to gravity connections along Yelm Hwy

$420

2016

5

Pipe Corrosion Abatement

Hydrogen sulfide reduction system in SE neighborhood

$150

2014

6

Pipe Corrosion Abatement

Hydrogen sulfide reduction system in NE neighborhood

$150

2016

7

STEP Pump Replacement

Replace 25% of STEP pumps

$300

2025

8

STEP Tank Replacement

Replace 25% of residential STEP tanks

$1,500

2030

Table 10.2

Lift Station Improvements

No.

Project Name

Description

Cost ($K)

Timing

9

Black Lake LS Upgrade

Replace lift station

$1,100

2014

10

Water Street Generator

Replace existing diesel generator

$150

2015

11

28th Ave. NW LS Property Purchase

Purchase property for future LS

$100

2015

12

Miller and Central LS Upgrade

Replace existing wet well and pumps

$750

2016

13

Miller and Ann Generator

Install diesel generator

$60

2017

14

Water St Force Mains Upgrade

Replace 18 and 30-inch force mains

$900

2018

15

Old Port 2 LS Upgrade

Increase capacity

$600

2019

16

Roosevelt and Yew LS Upgrade

Increase capacity and potentially relocate

$600

2021

17

Old Port 1 LS Upgrade

Increase capacity and potentially relocate

$600

2022

18

Jasper LS Upgrade

Replace lift station

$130

2023

19

AC Force Main Upgrades, Phase 1

Replace AC force mains at various locations

$900

2024

20

Rossmoor LS Upgrade

Replace lift station

$500

2025

21

East Bay Marina LS Upgrade

Replace lift station and force main

$750

2027

22

AC Force Main Upgrades, Phase 2

Replace AC force mains at various locations

$900

2029

23

Water St LS Replacement

Relocate and replace lift station

$4,600

2032

Table 10.3

Sewer Extension Projects

No.

Project Name

Description

Cost ($K)

Timing

24

Boulevard Sewer Extension at Morse Merryman Roundabout

Sewer main extension south to Log Cabin Roundabout

$750

2017

25

Future Sewer Extension at a Roundabout to be Determined

Sewer main extension at future roundabout

$750

2023, 2029

View Figure 10.4 Project Location Map

View Table 10.5 Summary Table of Wastewater Projects for 2014 - 2023

Table 10.6 Summary Table of Wastewater Projects for 2024 - 2033