14-DWU WWFOSP Lift Station Condition Assessment Tech Memo Final 20240108.pdf

FINAL

LIFT STATIONS AND DIVERSION

STRUCTURES CONDITION

ASSESSMENT TECHNICAL

MEMORANDUM

DWU Wastewater Facilities and Operations Strategic Plan

BLACK & VEATCH PROJECT NO. 414297

CITY PROJECT NO. 2022-00020260

PREPARED FOR

City of Dallas, Water Utilities Department

8 JANUARY 2024

Bl ac k

V ea tc h Ho ld in g Co m pa ny

3.

A ll rig ht s r es er ve d.

City of Dallas, Water Utilities Department | Lift Stations and Diversion Structures Condition Assessment Technical Memorandum

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Table of Contents

1.0 Introduction

2.0 Methodology and Approach

2.1 Asset Hierarchy

2.2 Condition Assessment

2.3 Performance Assessment

2.4 Data Review and Analysis

2.4.1 Remaining Useful Life

3.0 Condition Assessment Findings

3.1 Lift Stations

3.1.1 Cypress Waters II Lift Station

3.1.2 Seagoville Road Lift Station

3.1.3 Lawson Lift Station

3.1.4 Erickson Lift Station

3.1.5 Winstead Lift Station

3.1.6 Industrial Lift Station

3.1.7 Regal Row Lift Station

3.1.8 Rylie Road Lift Station

3.1.9 Christopher Place Lift Station

3.1.10 Lucky Lane Lift Station

3.1.11 Maylee Lift Station

3.1.12 McCommas Lift Station

3.1.13 Cedar Crest Lift Station

3.1.14 Van Cleave Lift Station

3.1.15 Cypress Waters I Lift Station

3.1.16 Cadiz Lift Station

3.2 Diversion Structures

3.2.1 Five Mile Diversion Structure

3.2.2 Sunbeam Diversion Structure

4.0 TCEQ Compliance

4.1 Site Access, Security, and Flood Protection Requirements

4.2 Dry and Wet Well Requirements

4.3 Pumps, Valves and Pipes Requirements

4.4 Emergency Provisions Requirements

5.0 Risk Assessment

5.1 Risk Assessment Results

6.0 Recommendations and Costs

6.1 Lift Stations

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6.1.1 Cypress Waters II Lift Station

6.1.2 Seagoville Lift Station

6.1.3 Lawson Lift Station

6.1.4 Erickson Lift Station

6.1.5 Winstead Lift Station

6.1.6 Industrial Lift Station

6.1.7 Regal Row Lift Station

6.1.8 Rylie Road Lift Station

6.1.9 Christopher Place Lift Station

6.1.10 Lucky Lane Lift Station

6.1.11 Maylee Lift Station

6.1.12 McCommas Lift Station

6.1.13 Cedar Crest Lift Station

6.1.14 Van Cleave Lift Station

6.1.15 Cypress Waters I Lift Station

6.1.16 Cadiz Lift Station

6.2 Diversion Structures

6.2.1 Five Mile Diversion Structure

6.2.2 Sunbeam Diversion Structure

LIST OF TABLES

Table 2-1 Risk Matrix Table 2-2 DWU Lift Station Physical and Performance Scoring Criteria Table 2-3 Lift Station and Diversion Structures COF Criteria Table 2-4 Asset Design Life Table 5-1 Assets with a LOF Score of 5 by Facility Table 5-2 Summary of High-Risk Assets by Facility Table 6-1 Summary of Costs by Lift Station and Diversion Structure Table 6-2 Cypress Waters II Lift Station Recommended Improvements Table 6-3 Seagoville Complete Lift Station Replacement Table 6-4 Seagoville Lift Station Recommended Improvements Table 6-5 Lawson Complete Lift Station Replacement Table 6-6 Lawson Lift Station Recommended Improvements Table 6-7 Erickson Complete Lift Station Replacement Table 6-8 Erickson Lift Station Recommended Improvements Table 6-9 Winstead Lift Station Recommended Improvements Table 6-10 Industrial Complete Lift Station Replacement Table 6-11 Industrial Lift Station Recommended Improvements

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Table 6-12 Regal Row Complete Lift Station Replacement Table 6-13 Regal Row Lift Station Recommended Improvements Table 6-14 Rylie Road Complete Lift Station Replacement Table 6-15 Rylie Road Lift Station Recommended Improvements Table 6-16 Christopher Place Complete Lift Station Replacement Table 6-17 Christopher Place Lift Station Recommended Improvements Table 6-18 Lucky Lane Complete Lift Station Replacement Table 6-19 Lucky Lane Lift Station Recommended Improvements Table 6-20 Maylee Lift Station Recommended Improvements Table 6-21 McCommas Lift Station Recommended Improvements Table 6-22 Cedar Crest Lift Station Recommended Improvements Table 6-23 Van Cleave Lift Station Recommended Improvements Table 6-24 Cypress Waters I Lift Station Recommended Improvements Table 6-25 Cadiz Lift Station Recommended Improvements Table 6-26 Five Mile Diversion Structure Recommended Improvements Table 6-27 Sunbeam Diversion Structure Recommended Improvements

LIST OF FIGURES

Figure 2-1 Lift Stations and Diversion Structures Map Figure 2-2 Generic Decay Curve Figure 3-1 Cypress Waters II Lift Station Figure 3-2 Seagoville Road Lift Station Figure 3-3 Lawson Lift Station Figure 3-4 Erickson Lift Station Figure 3-5 Winstead Lift Station Figure 3-6 Industrial Lift Station Figure 3-7 Regal Row Lift Station Figure 3-8 Rylie Road Lift Station Figure 3-9 Christopher Place Lift Station Figure 3-10 Lucky Lane Lift Station Figure 3-11 Maylee Lift Station Figure 3-12 McCommas Lift Station Figure 3-13 Cedar Crest Lift Station Figure 3-14 Van Cleave Lift Station Figure 3-15 Cypress Waters I Lift Station Figure 3-16 Cadiz Lift Station Figure 3-17 Five Mile Diversion Structure Figure 3-18 Sunbeam Diversion Structure

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Figure 4-1 TCEQ Compliance Scores Figure 5-1 Distribution of LOF Scores by Facility Figure 5-2 Distribution of COF Scores by Facility Figure 5-3 Distribution of Risk Classification by Facility

LIST OF APPENDICES

Appendix A. Condition Assessment Results ......................................................................................... A-1 Appendix B. Rehabilitation Recommendations and Opinion of Probable Construction Costs ............ B-1 Appendix C. TCEQ Checklist ................................................................................................................. C-1 Appendix D. Lift Station and Diversion Structures Assessment Guide ................................................ D-1

City of Dallas, Water Utilities Department | Lift Stations and Diversion Structures Condition Assessment Technical Memorandum

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1.0 Introduction

As part of the Wastewater Facilities and Operations Strategic Plan for the City of Dallas, Water Utilities Department (DWU) tasked Black & Veatch (BV) with subconsultants JQ Infrastructure (JQ) and Gupta and Associates (GAI) to perform condition assessment inspections at sixteen (16) lift stations and two (2) diversion structures within the DWU collection system. The condition of the assets will help determine the renewal and replacement projects for lift stations and diversion structures.

Prior to mobilizing to the field, a review of existing asset data documentation, including DWU GIS database and available record drawings was conducted, and a preliminary asset registry for the inspection areas was developed. This information was used to create a digital asset registry for the assets to be inspected. The purpose of the asset registry is two-fold: 1) Enabling field inspection crews to geospatially locate lift station assets and 2) Facilitate the collection of asset specific condition assessment data. The location of the lift stations and diversion structures inspected are shown in Figure 2-1.

Results of the lift station and diversion structure condition assessment and recommendations are presented in the following sections. As part of this TM, BV prepared a digital deliverable consisting of an excel file that provides the geospatial location, condition assessment inspection results, and field collected photographs.

This digital log will be delivered to DWU under a separate cover letter and can be used to update DWU’s asset registry.

2.0 Methodology and Approach

Condition assessment data was collected in the field using an electronic data collection form. The form was developed utilizing a mobile application installed on field inspectors’ portable devices. The form was pre-loaded with available asset registry data identified during Task 3 – Facility Assets Inventory, DWU Wastewater Facilities Operations and Strategic Plan (WWFOSP).

2.1 Asset Hierarchy

The asset registry defines the facility, asset types, and asset classes found at the lift stations and diversion structures and defines the logical relationships between those components. It also allows for the roll-up of costs, condition, performance, and risk scores by process, subprocess, or asset class.

2.2 Condition Assessment

Condition assessment of lift stations and diversion structures was performed between May 22 and May 24, 2023. Condition assessment results are presented in 6.2.2Appendix A. Rehabilitation Recommendations and Opinion of Probable Construction Costs are presented in 6.2.2Appendix B. Condition assessment results are based on visual TCEQ design requirements and physical observations made during the team’s field assessment work in accordance with DWU’s scoring criteria. The TCEQ Checklist is presented in 6.2.2Appendix C. Detailed criteria for physical condition scoring are provided in the Lift Station and Diversion Structures Assessment Guide submitted to DWU on May 4, 2023.

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Figure 2-1 Lift Stations and Diversion Structures Map

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2.3 Performance Assessment

Performance assessment results are a combination of operation and maintenance staff’s knowledge and experience, maintenance records, and measurable performance data. To assess an assets’ performance score, the condition assessment team collected operational performance, reliability, availability, and maintainability data based on a scoring system that ranged from 0 to 5.

A score of 0 represents an unknown condition, a 1 represents a (Good) condition and a 5 represents a (Failed) condition. Detailed criteria for an asset’s performance score are provided in the Lift Station and Diversion Structures Assessment Guide in 6.2.2Appendix D.

2.4 Data Review and Analysis

The condition assessment data collected for the lift stations and diversion structures were exported into a quality review application. Through this application staff subject matter experts from BV, JQ, and Gupta were able to review and address data gaps.

Upon completion of the quality review, condition assessment scores were analyzed utilizing the Business Risk Exposure (BRE) methodology provided by DWU. This protocol is based on the Water Environment Research Foundation BRE tool and incorporates the Enterprise Work-Order and Asset Management Systems (EWAMS) condition criteria and scoring scales as well as other key parameters to assess the Likelihood of Failure (LOF), Consequence of Failure (COF) and Risk to prioritization future CIP projects. Table 2-2 shows the LOF scoring system based on a 1 to 5 scale where 1 represents an asset in Good condition and 5 represents an asset in Failed condition.

COF is an impact of a failure calculated based on the rating structure presented in Table 2-3. This table shows the 1 to 5 scale where a score of 1 represents minimal or no impact and a score of 5 represents an extensive or major impact. For both the LOF and COF scoring system, a condition score of 0 represents Unknown or Not Applicable.

The calculation of an assets risk score consists of two components, namely LOF and COF. Risk scores for lift station were developed utilizing the following methodology:

1. Developing a risk matrix based on an assets LOF and COF. The developed matrix is presented in Table 2-1.

2. Developing LOF definitions and weighting factors. The developed LOF criteria is presented in Table 2-2.

3. Developing COF definitions and weighting factors. The developed COF criteria is presented in Table

2-3.

4. Calculate the Risk Score (RS) by multiplying LOF x COF. Based on the 5 x 5 LOF and COF matrix a lift stations Risk Score ranges from 1 (Very Low) to 25 (Very High Risk).

5. Plotting the Risk Score for each asset.

DWU’s Risk Classification Matrix for assets is broken down into the five categories as presented in Table 2-1.

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Table 2-1 Risk Matrix

Likelihood of Failure Score

< 1.5 1.5 - 2.49 2.5 - 3.49 3.5 - 4.49 > 4.5

1-Good 2-Acceptable 3-Fair 4-Poor 5-Failed

Co ns eq ue nc e of F ai lu re S co re

4.

5-Very High Medium Medium High Very High Very High

3.

- 4 .4

4-High Low Medium Medium High Very High

2.

- 3 .4

3-Moderate Low Low Medium High High

1.

- 2 .4

2-Low Very Low Low Low Medium Medium

1.

1-Very Low Very Low Very Low Low Low Low

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Table 2-2 DWU Lift Station Physical and Performance Scoring Criteria

Criteria Weight

Score

1 2 3 4 5

Ph ys ic al

Co nd iti on

30% Good – Asset in good condition with no defects

Acceptable – Asset has minor defects

Fair – Asset has defects that may affect reliability and efficiency

Poor – Asset is highly unreliable or inefficient

Failed – Asset is no longer able to function in its current condition

O pe ra tio na l

Pe rf or m an ce

30% Exceeds current requirements

Meets current requirements, but with room for improvement

Obvious concerns;

cost/benefit questions

Difficult to sustain performance

Failing; not capable of sustaining required performance

Re lia bi lit y

15% Infrequent breakdown Occasional breakdown Periodic breakdown Continuous recurrent breakdown Virtually inoperable

Av ai la bi lit y

10% Out of service for only short periods

Out of service for moderate period.

Moderately difficult to return to service

Increasingly difficult to return to service; parts becoming a challenge

Extensive downtime duration; difficult to return to service, parts difficult to acquire parts;

rare skills required

Virtually impossible to return to service

M ai nt ai na bi lit y

15%

Largely preventive maintenance with some corrective maintenance beginning to show up;

baseline monitoring

Increasing minor maintenance required;

periodic corrective maintenance including some repair shortening of monitoring intervals

Scheduled maintenance becoming frequent; more experienced trades people required for maintenance;

frequency of work orders increasing substantially with short monitoring intervals

Work orders well above average for type of asset.

Recurrent minor repair;

close monitoring required; most senior people required to sustain performance

Maintenance is frequent with recurrent patterns of failure; asset must be virtually constantly monitored to sustain performance

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Table 2-3 Lift Station and Diversion Structures COF Criteria

Criteria Weight Category

Score

1 2 3 4 5

Ec on om ic

Im pa ct

25% Financial Moderate cost, <$100k High cost, <$500k Diverts capital;<$2 million

Painful change of priorities, <$10 million

Likely to trigger rate Increase, staff changes, >$10 million

Pu bl ic Im pa ct

25%

Loss of Service Can be out of service indefinitely

Cannot be down a month

Cannot be down a week

Cannot be down 8 hours

Cannot be down one hour

Public Safety No impact Minor injury Moderate injury and some sickness

Major injury, sickness

Potential fatality, widespread injury, and sickness

Worker Safety No impact Minor injury Moderate injury and some sickness

Major injury, sickness

Potential fatality, disability, chronic sickness

Agency's Image No media or no consequence Neutral coverage Adverse media Continual; political opposition Nationally adverse media

En vi ro nm en ta l

50%

Water Quality No complaints; no impacts to receiving water

A few complaints;

minor impacts to receiving water

Moderate complaints;

observable impacts to receiving water

Extensive complaints; odor complaints in the downstream receiving water

Extensive system- Fish kill in the receiving water

Regulatory Compliance No consequence Minor violation -reporting only Regulatory sanction possible Regulatory sanction Extensive regulatory sanction/ fines

Environmental Hazard

Short duration, small quantity offsite spillage

NA

Many inconvenienced;

moderate health and habitat issues in the receiving water

Severe health and habitat issues; some mandatory vacation of activities in the receiving water

Large areas vacated and closed to public access extensive specialized containment cleanup required in the receiving water

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These risk score categories can be generally defined as:

Very Low Risk – Assets that are new or function as a new asset and are not essential or critical to utility operations.

Low Risk – Assets that are in good and acceptable condition and will not impact utility operations when they fail.

Medium Risk – Asset that are in acceptable to poor condition and may impact utility operations when they fail.

High Risk – Assets that are in fair to failed condition and may moderately impact utility operations when they fail.

Very High Risk – Critical assets that are in poor condition or have failed and will highly impact utility operations.

2.4.1 Remaining Useful Life

Replacing assets simply based on chronological age could result in unnecessary expenditures because the asset can be performing better than expected and have a longer life than initially anticipated. By understanding the condition of the asset and calculating the Remaining Useful Life (RUL), replacement or refurbishment of assets can be safely delayed. The remaining useful life of an asset can be calculated in one of two ways. It can be calculated based on an asset’s installation date, if condition assessment information is not available, or calculated based on an assets condition score. An example on how to calculate the useful life of a valve installed in 2000, using both methods, are provided below:

2.4.1.1 Remaining Useful Life Based on Age

Subtract an asset’s installation date (in years) from the current calendar year to calculate an asset’s age.

Subtract the assets age from the estimated design life for the asset. The estimated design life for lift station assets is provided in Table 2-3.

● Equation 1

Current Calendar Year – Installation Year = Assets Age (2023 – 2000) = 23

● Equation 2

Design Life from Table 2-4– Asset Age from Equation 1 = RUL (years) (25 – 23) = 2 (years).

Table 2-4 Asset Design Life

Asset Asset Design Life (yr.)

Well 80

Vault 60

Pumps- Submersible 15

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Asset Asset Design Life (yr.)

Pump – Sump 15

Pump Assemblies 20

Valve – Check 60

Valve - Isolation 60

Control Panel 15

Flow Meter 15

Generator 25

Sluice/Slide Gate 28

Actuator 20

Instrument 15

Piping 80

Paving 25

Note: Asset Design Life is based on the Water Research Foundation (WERF) Sustainable Infrastructure Management Program Learning Environment (SIMPLE) model

2.4.1.2 Remaining Useful Life Based on LOF Condition Score

An asset’s LOF condition score can be used to estimate the useful life consumed using the generic decay curve as shown in Figure 2-2 and the Asset Design Life’s presented in Table 2-3. If asset specific decay curves have been developed for each asset class those decay curves should be used in place of the generic curve.

Figure 2-2 Generic Decay Curve

1.0

2.0

3.0

4.0

5.0 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Co nd iti on

S co re

Useful Life Consumed (%)

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Using the decay curve in Figure 2-2, the useful life consumed for a valve installed in 2000, with a condition score of 3, is 75%. To calculate the assets RUL in years:

Multiply the assets design life in Table 2-3 by 75%.

Subtract the assets Useful Life Consumed in Years (Equation 3) from the assets Design Life

● Equation 3 – Useful Life Consumed in Years

Table 2-4 Asset Design Life X Useful Life Consumed (%)

25 x 0.75 = 18.75

● Equation 4 – Remaining Useful Life (Years)

Table 2-3 Asset Design Life - Useful Life Consumed (Years)

25 – 18.75 = 6.25 (Years)

By calculating an asset’s RUL, in this example, the valve will meet its designed level of service for an additional 4.25 years.

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3.0 Condition Assessment Findings

3.1 Lift Stations

3.1.1 Cypress Waters II Lift Station

Figure 3-1 Cypress Waters II Lift Station

3.1.1.1 Overview

The Cypress Waters II Lift Station (CYPII), located at 9496 Cypress Waters Blvd., has a firm capacity of 6.84 MGD. The lift station receives flow from the Cypress Waters development and then pumps flow via a 24-inch pressurized force main around the east side of North Lake. Cypress Waters II is an active lift station.

The lift station has four (4) 25 HP, 2.28 MGD (1,583 GPM) submersible pumps located in a 103,000-gallon wet well. The lift station also has an intake structure with two intake channels that direct flow into the wet well.

The condition assessment team evaluated the lift station on May 23, 2023, and noted the following observations:

3.1.1.2 Site Civil

As the most recently constructed lift station, the site paving and drainage were in good condition with no noticeable signs of erosion or damage. However, the site is not easily accessible. The only current access to the lift station site is through unpaved trails, primarily used for biking and hiking.

There is a fire hydrant within the lift station site, but the water pressure varies and often does not have the required pressure to provide fire protection. The water at the hydrant is supplied from the nearby North Lake, and the pressure is dependent on the lake level. There is a fire extinguisher in the electrical building, but it is out of date for a maintenance check and its operability is unknown.

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The main entrance slide gate motor was not functioning during the inspection site visit and had to be manually pushed open.

3.1.1.3 Structural

The lift station consists of a below-grade concrete wet well with submersible pumps. Aluminum access hatches provide access to the pumps. The discharge piping and the valves are located in a vault structure adjacent to the lift station structure. The valve vault has a steel grated cover on top with ladders to access the interior of the vault structure. An influent splitter box/control structure is located on the south side with sluice gates to control flow into the wet well. A bridge crane is supported by a structural steel framed canopy structure on top of the station to access the pumps and the valves. The electrical building is located on the east side of the station. The electrical building consists of a concrete foundation slab with a CMU/brick veneer enclosure. The roof framing consists of pitched roof joists with a standing seam metal deck.

The interior concrete surfaces of the wet well are generally in good condition. There is a protective coating installed on the wall surfaces that appears to be intact. The underside of the wet well slab was not accessible at the time of the condition assessment.

The valve vault is in acceptable condition with no visible signs of concrete distress. The gratings are in good condition with no leaks or spalls visible. There were no visible cracks on the walls or floor slab. However, the ladder to access the dry well is difficult to use and does not have a ladder-up post. The intake structure is in acceptable condition. There were minor cracks on the upper slab that had been repaired previously.

DWU staff noted that the bridge crane has not been operated for some time now due to equipment issues.

3.1.1.4 Mechanical

The pumps are Flygt, Model No. NP3153, and were installed in 2017. All three pumps were in the wet well and not visible at the time of inspection but were operable and with no noted deficiencies. One pump was tested during the inspection, and no performance issues were detected. Pump condition is rated as fair due to the harsh operating conditions and the age of the equipment.

Piping in the wet wells is stainless steel and are in acceptable condition. The piping on the downstream end of the valve vault is in acceptable condition with only minor chips and flaking in the coating. On the upstream end of the vault all piping is stainless steel and in acceptable condition. All valves in the valve vault are in acceptable condition with only minor chips in the coating.

3.1.1.5 Electrical and Instrumentation

3.1.1.5.1 Electrical

The lift station receives power from a bank of three pole mounted transformers. The capacity of the transformers could not be identified from ground level. 480 V power routes from the transformers to the electrical building where there resides a 1600A rated main distribution switchgear. The switchgear has breakers for the main incoming power, generator incoming power, load bank for generator testing, and feeder breakers for MCC-A and MCC-B.

MCC-A and MCC-B are each rated for 480 V, 600 A. MCC-A contains breakers and starters to feed the crane, odor control system, and lift station pump 1 and pump 3. MCC- A also feeds primary and secondary feeds to 15 kva transformer. MCC-B feeds lift station pumps 2 and 4.

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As mentioned previously, the site contains a generator which provides backup power to the entire lift station site. The generator is rated for 300 kW at 480 V. The generator main control panel is located in the electrical room remote from the generator. The ATS and generator switchboard are also located in the electrical room.

The generator is tied to the main distribution switchgear via an automatic transfer switch. Upon sensing loss of utility power, the generator energizes, opens the main utility breaker, and closes the main generator breaker to bring the lift station back online. This process occurs automatically and is tested periodically to ensure proper operation.

The MCCs feed two lift station pump control panels provided by the pump vendor with all the integral controls associated with the lift station pumps. There are two control panels each dedicated to a wet well.

The MCCs also feed various other equipment onsite include a low voltage transformer and panelboard for lights, HVAC, receptacles, instrumentation, and security.

3.1.1.5.2 Instrumentation

The lift station is in good condition as far the instrumentation devices and PLC system. This lift station is monitored from the Wastewater Collection Monitoring Section located at 8915 Adlora Lane. The lift station is monitored by SCADAPack PLC, and Sensaphone device with a radio to send the lift station status to the Operators through a smart phone app. The pumps are monitored and controlled by manufacturer provided control panels. During the site visit, one of the DWU staff mentioned that the Flygt pumps Multi Smart control device is not recognizing when the other manufacturer provided control panel is in fail status. The operator only found out that the panel failed when the lead pump failed, and the lag pump did not start.

3.1.2 Seagoville Road Lift Station

Figure 3-2 Seagoville Road Lift Station

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3.1.2.1 Overview

The Seagoville Road Lift Station (HC215), located at 13322 Seagoville Road, has a firm capacity of 0.72 MGD.

The lift station receives flow from nearby residential service connections and then pumps flow via a 6-inch pressurized force main to the gravity sanitary sewer system along Seagoville Road.

The lift station has two 7.4 HP, 0.72 MGD each (500 GPM) pumps located in a dry well. There is a 1 HP sump pump on the floor of the dry well.

The condition assessment team evaluated the lift station, including a confined space entry to the bottom of the dry well, on May 22, 2023, and noted the following observations:

3.1.2.2 Site Civil

The lift station site has a concrete drive approach from Seagoville Road and adequate unpaved space to safely park maintenance vehicles off the roadway.

The site is completely fenced with 6-ft high chain link security fencing and can be accessed through two manual double swing gates. The fencing has minor defects, but overall, the fencing and gate are in acceptable condition.

The ground surface within the fenced area consists of crushed stone surface surrounding the lift station concrete slab. Site drainage is in poor condition. There is indication that during rain events, drainage from the surrounding areas flows through the lift station site seeping rainwater into the wet well and meter vault.

3.1.2.3 Structural

The lift station structures include a precast concrete wet well with a manhole lid for access, a fabricated steel dry well that houses the pumps and valves, a concrete meter vault with metal lid, and a concrete pad on top of the wet well.

The concrete wet well is in acceptable condition. Minor damage to the walls due to modifications for pipe penetrations and minor cement matrix loss was observed. The fabricated steel dry well is accessed from grade level with a vertical cylindrical manway and is considered a confined space. The dry well is in acceptable to fair condition with minor corrosion at the base of the steel structure, particularly in joints and corners. The meter vault is in acceptable condition with no signs of structural distress. Several feet of standing water was observed in the vault at the time of observation. The concrete pad at grade level was in acceptable condition.

Accessibility into the dry pit is difficult. The dry pit is a confined space and requires manual ventilation to enter the confined space following confined space entry procedures to perform planned or emergency maintenance and repairs. To enter the dry pit a temporary ventilation duct is inserted into the pit constricting the 3-feet diameter riser space, which poses a safety risk for maintenance personnel when they are descending or ascending the ladder. Additionally, the ladder-up safety post is not installed, and electrical wires and cables are attached to the ladder side rail.

3.1.2.4 Mechanical

The pumps are Flyght, Model No. NP3127, and according to DWU’s records, the pumps were installed in 2010. These pumps are installed in a vertical, dry-pit pump configuration and were visible at the time of the

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inspection. Pump 1 appears to be relatively new and is in an acceptable condition. Pump 2 has visible surface corrosion and is in fair condition. No leaks or unusual noises were noted during operation.

The sump pump is noted to be in poor condition with significant surface corrosion. No pit flooding was observed at the time of the inspection.

The piping in the dry well is aging but in fair condition. There is some corrosion, mostly on the flange bolts and some light surface rust elsewhere. The coating is chipped and flaking in a few places but is minor. The check valves and gate valves are also aging, but in fair condition with minor surface corrosion.

There is a floor drain at the bottom of the meter vault that drains back to the wet well, but the flap valve in the wet well is stuck closed.

3.1.2.5 Electrical and Instrumentation

3.1.2.5.1 Electrical

Seagoville Road Lift Station is powered through an overhead service at 120/240 V. The service routes to a service disconnect, then underground to the pump control panel and a miscellaneous control panel. The site has the capability to be powered with a portable backup generator through a receptacle connection.

The pump control panel powers and controls two lift station motor and serves as the main distribution panel for the rest of the miscellaneous loads. The pump control panel has one main breaker, limiting the ability for safely perform maintenance without shutting down both motors. The miscellaneous panel contains a power strip, receptacle, and ThermoPolysonics device. The pump control panel is in good condition, and the miscellaneous panel is in fair condition.

Within the lift station dry well, the sump pump is in poor condition and has significant corrosion. There are exposed cables and receptacles at a level that exposes them to flooding, and Pump No.2 shows signs of degradation.

3.1.2.5.2 Instrumentation

This Lift Station is operating with no issues. All the instrumentation devices are in good condition. The Sensaphone device with a radio was installed to send the lift station status to the Operators through a smart phone app.

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3.1.3 Lawson Lift Station

Figure 3-3 Lawson Lift Station

3.1.3.1 Overview

The Lawson Lift Station (HC214), located at 14111 Lasater Road, has a total capacity of 3.17 MGD. The lift station receives flow from nearby residential neighborhoods, mobile home parks and an elementary school and then pumps flow via a 20-inch pressurized force main southwest along Lawson Road.

The lift station has two (2), 88 HP and one (1), 85 HP, 1.58 MGD each (1,101 GPM) submersible pump located in a 42,000-gallon wet well.

The condition assessment team evaluated the lift station on May 22, 2023, and noted the following observations:

3.1.3.2 Site Civil

There is a creek immediately adjacent to the lift station site. DWU operators indicated the site is susceptible to flooding during large rain events. They stated that during wet weather events, flow from the adjacent creek backs up to the lift station site and then to wet well through hatch openings.

The lift station does not have a paved driveway or parking spaces separated from the road for easy maintenance and operator access. The ground surface within the fenced site is well maintained and consists of concrete slabs and crushed stone. The chain link security fence and manual slide gate are in good condition with no noticeable damage or deterioration.

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3.1.3.3 Structural

The lift station structures include a combined cast-in-place concrete structure that includes a wet well and a dry well with metal access hatches. The roof of the structure supports a generator and miscellaneous electrical and mechanical equipment. The wet well houses the pumps while valve vault houses valves and piping.

The concrete wet well is in fair to acceptable condition. The wet well concrete walls are lined with a coating that has failed over large areas and is peeling away. Moderate cement matrix loss was observed at several locations in the wet well, particularly at locations where the coating had failed. The roof hatches in the wet well have an integrated fall safety grating, the paint/coating on the safety grating had failed over large portions of the grating.

The valve vault is in acceptable to fair condition. However, the ladder to access the dry well is difficult to use and does not have a ladder-up post. Access to the valve vault requires a confined space entry and the headroom in the valve vault is restricted for regular maintenance of valves and piping. In addition, the valve vault hatches are not located directly over the valves, making valve maintenance difficult.

3.1.3.4 Mechanical

The pumps are Flyght, Model No. NP3301, and were installed in 2022. The pump operation revealed no excessive turbulence or leaks. The pump rails had a large buildup of grease but were in good condition. Due to the age of the equipment, the pump condition is rated as acceptable.

Piping located in the wet well was covered with grease. There is some rust-colored staining of the grease which may be an indication of corrosion of the piping beneath the grease. Piping is likely in fair to poor condition, but further investigation is required.

Not all piping in the valve vault was visible during the inspection, the piping that was visible during the inspection has extensive surface corrosion. Flange bolts also have corrosion visible. As with the piping not all valves were visible during the inspection, but the ones that were also have some corrosion visible and are in fair condition.

3.1.3.5 Electrical and Instrumentation

3.1.3.5.1 Electrical

The power at Lawson Lift Station is delivered through an overhead power drop at 480 V. The power is routed to a main disconnect, an automatic transfer switch (ATS), and then to the pump control panel. Standby power is provided by an on-site 250 kW Kohler diesel generator and connects to a Kohler ATS. The ATS and generator show rusting on the enclosure. The pump control panel provides power and controls for three pumps. The Pump 1 starter was not functioning during the site visit.

Site miscellaneous power and lighting loads are tapped from the main disconnect to a 480 V power panel and 10 kVA 480-120/240 V 1Φ miniload center.

The lift station is in good condition and recently went through rehabilitation. Most of the electrical equipment was replaced during the rehabilitation. The generator and ATS age and condition are the main concerns at the site; however, they are in good working condition.

City of Dallas, Water Utilities Department | Lift Stations and Diversion Structures Condition Assessment Technical

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3.1.3.5.2 Instrumentation

This Lift Station is operating with no issues. All the instrumentation devices are in good condition. The Sensaphone device with a radio was installed to send the lift station status to the Operators through a smart

3.1.4 Erickson Lift Station

Figure 3-4 Erickson Lift Station

3.1.4.1 Overview

The Erickson Lift Station (WR201), located at 17808 Coit Road, has a firm capacity of 1.68 MGD. The lift station receives flow from a nearby nursing home via a private wastewater line and then pumps flow through a 10-inch pressurized force main south along Coit Road.

The lift station has two (2) 45 HP, 1.68 MGD each (1,170 GPM) submersible pumps located in a 7,000-gallon wet well. The lift station also has separate valve and meter vaults.

The condition assessment team evaluated the lift station on May 24, 2023, and noted the following observations:

3.1.4.2 Site Civil

The lift station has a 15-ft wide concrete driveway with several paved parking spaces providing easy access for operators and maintenance personnel.

The lift station grounds within the fenced site are well maintained with no visible evidence of erosion or flooding. The chain link security fence is in acceptable condition.

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3.1.4.3 Structural

The lift station structure consists of below-grade circular cast-in-place concrete wet well with submersible pumps. The roof of the wet well is a removable precast concrete slab with an aluminum access hatch for pump access. The valve vault structure is cast-in-place concrete construction and is located adjacent to the lift station structure. The stand-by generator and miscellaneous electrical and mechanical equipment is located on isolated structural concrete pads on the site's north side.

The concrete surface in the wet well is in acceptable condition with no visible signs of spalling or cracking.

The wet well concrete walls are lined with a coating that is largely intact. There are isolated locations of coatings failure visible at the lower level of the lift station. The roof hatches in the wet well have an integrated fall safety grating and are in good condition.

The concrete surfaces at the valve vault structure and the access hatches are in good condition. The structure is about 5-feet deep and no permanent ladder installed. The grated sump cover is severely corroded.

The meter vault structure on the downstream side is generally in good condition, however there is standing water inside the vault that prevents maintenance access. The permanent ladder in this vault is missing the ladder-up safety post that would allow for safe access.

3.1.4.4 Mechanical

The pumps are Flyght, Model No. NP302. Based on DWU records. Pump 1 was installed in 2007, and Pump 2 was installed in 2015. The pump operation test revealed no excessive turbulence or leaks. The pump rails are in acceptable condition. Due to the age of the equipment, the pump condition is poor for Pump 1 and fair for Pump 2.

Discharge piping from the submersible pumps in the wet well to the valve vault is stainless steel and in acceptable condition. The piping downstream of the valves in the valve vault is in poor condition with significant corrosion visible. Both the plug valves and check valves have significant surface corrosion.

3.1.4.5 Electrical and Instrumentation

3.1.4.5.1 Electrical

The Erickson Lift Station receives power through an underground service at 480 V. The power is routed to a main disconnect, an ATS, and then to the pump control panel. Standby power is provided by an on-site 150 kW Caterpillar diesel generator and connects to a Kohler ATS. The generator and ATS were inoperable at the time of the site visit. The electrical group indicated that the generator was struck by lightning, resulting in a loss of operation. The mismatch of generator and ATS manufacturers can provide coordination issues for staff. The ATS shows signs of corrosion on the enclosure and some of the internal components.

Site miscellaneous power and lighting loads are tapped from the ATS at 480 V to a mini-load center. The pump control panel provides power for two motors. The two motors are started with reduced voltage soft starters (RVSS) and are controlled by the 120 V wet well Control Panel.

Additionally, the following was noted during the site visit:

The blower on site has signs of arcing on the enclosure due to the decay of the insulation in the power wiring, presenting a safety and operational hazard.

The mini-load center is causing warping of the Unistrut rack due to its weight.

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3.1.4.5.2 Instrumentation

This lift station is equipped with a flowmeter but appeared to be inoperable. The lift station is monitored by a Sensaphone device with a radio, and the Operators can monitor the lift station status through a smart phone app.

3.1.5 Winstead Lift Station

Figure 3-5 Winstead Lift Station

3.1.5.1 Overview

The Winstead Lift Station (EB203), located at 2200 Winstead Drive, has a firm capacity of 1.28 MGD. The lift station receives flow from several neighborhoods on the south side of Winstead Drive and then pumps flow via an 8-inch force main to the sanitary sewer system approximately 60 linear feet southeast of the lift station.

The lift station has two (2) 10 HP, 1.28 MGD each (890 GPM) submersible pumps located. The condition assessment team evaluated the lift station on May 24, 2023, and noted the following observations:

3.1.5.2 Site Civil

The lift station site does not have a dedicated lift station driveway. Maintenance vehicles either park in the hiking trail parking lot or block a lane of traffic.

The lift station structures, and equipment are all within wrought iron fencing with a locked gate. The site within the fencing is well-maintained and consists of concrete slabs around the wet well and valve vaults and crushed stone applied to the remaining ground surface.

City of Dallas, Water Utilities Department | Lift Stations and Diversion Structures Condition Assessment Technical

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3.1.5.3 Structural

The lift station structure consists of below grade circular cast-in-place concrete wet well with submersible pumps. The roof of the wet well is a removable precast concrete slab with an aluminum access hatch for pump access. The valve vault structure is cast in place concrete construction and is located adjacent to the lift station structure. The concrete surfaces in the wet well and the upper slab are in acceptable condition with no visible signs of spalling or cracking. The wet well concrete walls have a protective coating. The access hatch at the wet well is in good condition.

The valve vault structure is generally in good condition with no visible signs of structural distress. The permanent ladder in this vault is missing the ladder-up safety post that would allow for safe access.

3.1.5.4 Mechanical

The pumps are Flyght, Model No. NP3123, and were installed in 1995. One pump was noted to have leaky seals by operator. The pump rails are in fair condition with some light corrosion. Due to the age of the equipment, the pump condition is rated as poor.

All piping located in the wet well has significant corrosion and pitting along the entire length of the pipe. It is not clear if any coating was ever applied to the piping.

Piping within the valve vault is in fair condition with some light surface corrosion. The gate valves and check valve are also in fair condition with some surface rust visible.

3.1.5.5 Electrical and Instrumentation

3.1.5.5.1 Electrical

The Winstead List Station receives power through an overhead service at 120/208 V. The service routes to a service disconnect underground to an electrical rack. The electrical rack has the pump control panel, a miscellaneous electrical panel, and a light pole mounted to it. The site has the capability to be powered with a portable backup generator through a receptacle connection.

The pump control panel powers and controls two pumps and serves as the main distribution panel for the rest of the miscellaneous loads. The miscellaneous panel contains 120 V power equipment and the generator receptacle. Due to the location of the generator receptacle, the panel must be open for a generator connection, allowing rain to egress into the control panel. There is no automatic transfer scheme or transfer protection.

Additionally, the following was noted during the site visit:

There is no main breaker at the pump control panel, which results in the loss of the ability to lock out and tag out the separate motors without shutting down the whole lift station.

Rust is present on the equipment rack supporting the electrical equipment.

3.1.5.5.2 Instrumentation

This Lift Station is operating with no issues. All the instrumentation devices are in good condition. The Sensaphone device with a radio was installed to send the lift station status to the Operators through a smart

City of Dallas, Water Utilities Department | Lift Stations and Diversion Structures Condition Assessment Technical

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3.1.6 Industrial Lift Station

Figure 3-6 Industrial Lift Station

3.1.6.1 Overview

The Industrial Lift Station, located at 1329 S. Riverfront Boulevard, has a firm capacity of 0.75 MGD. The lift station receives flow from the industrial and commercial properties along Industrial Boulevard between Cadiz Street and Corinth Street and then pumps flow via a 4-inch pressurized force main to the gravity sanitary sewer on the north side of Industrial Boulevard.

The lift station has two 7.5 HP, 0.75 MGD each (521 GPM) dry pit/wet pit pumps located in a dry well immediately adjacent to the wet well.

The condition assessment team evaluated the lift station, including a confined space entry into the dry well, on May 23, 2023, and noted the following observations:

3.1.6.2 Site Civil

The Industrial Lift Station site is immediately adjacent to a thoroughfare and does not have a driveway or dedicated parking spaces. There is an extended shoulder along the thoroughfare that allows space for maintenance personnel to park their vehicles, but any maintenance involving heavy equipment or vac trucks will most likely need to shut down an additional roadway lane.

The existing chain link fence is topped with barbed wire and outward-facing intruder bars. The fencing is in fair condition with minor defects, including several bent crossbars, leaning fence posts and misaligned gate.

The ground surface within the lift station fencing shows significant signs of erosion and flooding. Most of the crushed stone surface has been washed out. Due to the proximity of the nearby creek, the lift station is frequently flooded during large rain events.

City of Dallas, Water Utilities Department | Lift Stations and Diversion Structures Condition Assessment Technical

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3.1.6.3 Structural

The lift station site includes a wet well constructed of brick masonry liner. The pumps and valves are housed in a dry pit which is a buried steel structure. The access to the dry pit is through a 3-feet diameter riser steel pipe with a steel ladder attached to the riser. The dry pit is classified as a confined space.

The concrete wet well is in acceptable condition. The wet well showed no visible masonry brick failures. The access steps within the wet well are severely corroded and should not be used for access. The concrete around wet well access hatch has minor cracks and concrete spalling around the exterior. The manhole cover over the wet well shows signs of moderate to severe corrosion.

The dry pit structure is in overall fair structural condition. Severe corrosion of the steel chamber housing the pump and valves was observed. Isolated locations of water infiltration on the floor of the dry pit were also observed. Miscellaneous metal components and the piping and metal components have moderate to severe corrosion.

Accessibility into the dry pit is difficult. The dry pit is a confined space and requires manual ventilation to enter the confined space following confined space entry procedures to perform planned or emergency maintenance and repairs.