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Item 9E - Final CITY OF Item 9E SOUTHLAKE MEMORANDUM (June 20, 2017) To: Shana Yelverton, City Manager From: Rob Cohen, Director of Public Works Subject: Approve a Professional Services agreement with RJN Group, Inc., to conduct a Sanitary Sewer System condition assessment in an amount not to exceed $227,200 Action Requested: Approve a Professional Services agreement with RJN Group, Inc., to conduct a Sanitary Sewer System condition assessment in an amount not to exceed $227,200. Background Information: In 2007, the City contracted with RJN Group, Inc. to perform a comprehensive Sanitary Sewer Evaluation Survey (SSES). This study was conducted over a period of three years with the purpose of identifying any potential deficiencies in the City's wastewater collection infrastructure. Southlake's wastewater collection system consists of 208.74 miles of pipe, 3,760 manholes, 13 wastewater lift stations and 8,770 service connections (8,737 are active). While the City's wastewater collection systems in the southern basins are approximately 35 years old, and 18 years old in the northern basins, it is a best management practice to evaluate the integrity of the collection system approximately every ten years. Wastewater collection systems are, by design, primarily non- pressurized, gravity-flow pipeline networks. For that reason, defects in pipes and other system components are not readily apparent as they are in water distribution systems. In order to take advantage of the natural terrain, these gravity systems often follow creeks and other drainage ways. This placement makes them vulnerable to external groundwater pressure resulting in the infiltration of significant amounts of water where defects are present. Another source of inflow into the system results during rain events when manholes, cleanouts and other structures are subjected to flooding and standing water as well as any illicit connections from rain gutters. Item 9E Over the course of the last ten years, Wastewater personnel have worked to complete corrective action items identified in the SSES to maintain the wastewater system in good condition. Some of these corrective items include point repairs on the sewer main; elimination of direct open access points; installation of sealant between manhole cover and concrete structure; and rehabilitation of deteriorating manhole structures by applying an epoxy coating to deter corrosion from hydrogen sulfide and methane gases. In addition, per the U.S. Environmental Protection Agency (EPA), municipalities are required to develop a comprehensive Capacity, Management, Operation, and Maintenance (CMOM) Plan for their wastewater collection systems. The CMOM identifies all aspects of the wastewater collection system and the day-to-day operations as well as future planning for growth. In FY 2017, City staff worked with Freese & Nichols, Inc. to develop Southlake's CMOM Plan. As part of the FY 2017 CMOM plan gap analysis, it is necessary for the City to perform a current condition assessment of the wastewater infrastructure. It should be noted that the proposed condition assessment capitalizes on the results of the original SSES to confirm corrective action has remedied any deficiencies identified back in 2007. The proposed condition assessment will aid the City in identifying any other areas that need attention to prevent inflow and infiltration (I/I) into the wastewater collection system. Excessive inflow and infiltration increases the City's cost of treatment to the Trinity River Authority (TRA) wastewater treatment facility. Therefore, performing a condition assessment aids the City in corrective measures and managing treatment costs. Financial Considerations: Funding for the Professional Services agreement with RJN Group, Inc., to conduct a Sanitary Sewer System condition assessment in an amount of $227,200 is partially available in CIP project account 00039 in the amount of $180,000. The balance to complete the assessment may be transferred from the Utility CIP Residual Account in the amount of$47,200 upon Council approval. The study also includes temporary flow monitoring to aid the City in identifying areas of current I/I concern with the intent of correcting these to manage wastewater treatment costs, therefore, this study may provide for cost avoidance of unnecessarily treating ground water from inflow and infiltration. Item 9E Strategic Link: The approval of this Professional Services agreement links to the City's strategy map relative to the focus area of Infrastructure. The specific corporate objectives that are met by these services are to (132) collaborate with select partners to implement service solutions and (F2) invest to provide and maintain high quality public assets. Citizen Input/ Board Review: N/A Legal Review: N/A Alternatives: City Council may approve or deny this Professional Services agreement. Supporting Documents: Attachment A: RJN Group Proposal Staff Recommendation: Approve a Professional Services agreement with RJN Group, Inc., to conduct a Sanitary Sewer System condition assessment in an amount not to exceed $227,200. Staff Contact: Rob Cohen, Director of Public Works Cristina McMurray, M.P.A, C.P.M, Deputy Director of Public Works/Operations Attachment A www.rjn.com ringroun JL The Choice for Collection System Solutions June 1, 2017 Cristina McMurray Deputy Director Public Works Operations 1950 E. Continental Blvd. Southlake,TX 76092 RE: Sanitary Sewer Flow Monitoring and Field Investigation Services Dear Cristina: Thank you for the opportunity to provide you with a proposal for flow monitoring sewer investigation services for Southlake,Texas. We understand that the City is interested determining the capacity and performance of the sanitary sewer system as a part of the City's overall CMOM Efforts. We are proposing system-wide flow monitoring along with smoke testing and dyed water flooding in select areas designated by Southlake staff. The proposed flow monitoring scope includes twenty(20)gravity flow meters and five (5) rain gauges proposed for a monitoring period of 60 days. A detailed scope of services for the Flow Monitoring and Field Investigation Services in attached.The abridged scope of services for the flow monitoring is as follows: Flow Monitoring Equipment—The equipment will be redundant depth-velocity meters outfitted with a pressure transducer, ultrasonic depth sensors and Doppler velocity sensor.This equipment will capture flow rates under varying hydraulic conditions, such as back-up and surcharge.The equipment will be activated to record the depth and velocity at 5 minute intervals. Wireless Telemetry- Remote Terminal Units (RTU) shall be provided at each flow monitoring and rain gauge location to remotely collect the data. On a daily basis, all data stored in the remote RTU will be collected by the host system and available for viewing by authorized parties. Installation —The sensors will be mounted on a thin metal ring inserted on the upstream pipe.The cabling will be secured to the manhole walls and attached to a data logger at the top of the manhole for easy access. Prior to leaving the site, each flow monitor will be configured and activated. Finally,the equipment will undergo a series of diagnostic tests and calibrations to validate and confirm the meter data. Hydraulic Calibrations— Each monitored location will be calibrated at installation and during scheduled visits,thereafter. Calibration involves comparing the returned sensor values against independent devices to ensure that the hydraulic characteristics and various flow regimes will support the accuracy level desired. A velocity profile will also be obtained during each calibration by measuring the 12160 Abrams Road, Suite 400 D. 972.437.4300 972.437.2707 www.rjn.com n r� groun JL The Choice for Collection System Solutions Page Two instantaneous velocity at pre-defined depths, and then integrated to derive an average for comparison to the meters calculated average velocity. Data Management and Maintenance— Each flow meter will be collected by the Host System daily and the data shall be reviewed by the data analyst twice per week. During each review, data will be graphed to check for inconsistencies, gaps, or adverse trends. In the event that a meter or sensor is not performing correctly, a field crew will be dispatched to diagnose the problem and make necessary adjustments or repairs.Any equipment found to be working improperly will either be repaired at the site or replaced with a spare unit to minimize the data downtime. If necessary, a service visit will be conducted during the monitoring period to obtain calibrations. All field activities are recorded on standard field forms and provided at the end of the project. Data Analysis and Quality Control — RJN engineers will analyze data from each monitoring site immediately upon delivery from the field.The engineers will use various analytical tools, such as hydrographs, scattergraphs, and flow balancing methods to verify the accuracy and precision of the equipment, in addition to identifying unusual hydraulic events.The engineers will look for unique hydraulic conditions such as bottlenecks, surcharging, suspected overflows, and excessive inflow and infiltration. Indications of concern will be reported immediately. Data Delivery— Within four weeks of the meter removal, RJN will submit a report summarizing the flow data and our findings. Depth, velocity, and flow quantity data will be submitted in electronic format in excel, .csv or in model format as you prefer. 12160 Abrams Road, Suite 400 D. 972.437.4300 972.437.2707 + www.rjn.com nrou r� gp JL The Choice for Collection System Solutions Page Three Compensation—Compensation for providing these services will be based upon the following table: Description Quantit Unit Unit Cost Cost Project Administration 1 LS $17,050 $17,050 Flow Meter Investigation 20 Each $615 $12,300 Flow Meter Installation 20 Each $700 $14,000 Rain Gauge Investigation and Installation 5 Each $450 $2,250 FM Monitoring Period 1,200 Meter-Days $69 $83,256 RG Monitoring Period 300 Gauge-Days $21 $6,255 1/1 Hydraulc Analysis and Reporting 1 LS $24,579 $24,579 Flow Monitoring = $159,690 Project Administration 1 LS $8,690 $8,690 Public Relations/Smoke Notices 77,000 Linear Feet $0.15 $11,550 Smoke Testing 77,000 Linear Feet $0.50 $38,500 Dyed Water Flooding 10 Each $645 $6,445 Data Processing / Management 1 LS $6,750 $6,750 Source Defect Anaysis and Reporting 1 LS $6,300 $6,300 Field Investigations = $78,235 Flow Monitoring and Field Investigation as 2 separate projects = $237,925 NOTE: If both projects are combined into a larger project with one final report there's a savings in Project Administration and Reporting Costs Flow Monitoring and Field Investigation as 1 project = $227,200 We appreciate you considering our services and thank you for the opportunity to submit this proposal. We look forward to working with you on this project. Should you have any questions, please do not hesitate to contact me. CITY OF SOUTHLAKE,TEXAS RJN GROUP, INC. By: By: (s 4o"\, Laura Hill, Mayor Daniel Jack on, P.E., Vice President ATTEST: By: Lori Payne,TRMC City Secretary 12160 Abrams Road, Suite 400 D. 972.437.4300 972.437.2707 PROPOSAL FOR ENGINEERING SERVICES CITY OF SOUTHLAKE FLOW MONITORING AND SEWER INVESTIGATION SCOPE OF SERVICES A. SCOPE OF SERVICES The Services to be provided under this PROPOSAL shall consist of sanitary sewer evaluation study (SSES) services including system-wide flow monitoring and targeted field investigation services to complement the City's CMOM efforts. Flow Monitoring A.1.1 Project Administration The Engineer shall coordinate the overall work of the project to include all field inspections and engineering analysis. The Engineer shall provide monthly progress reports that will show the percent completion of each task. A bi-monthly progress meeting with the CITY OF SOUTHLAKE will be conducted. A.1.2 Field Verification Prior to beginning the flow monitoring project, the Engineer will verify sewer line interconnectivity and sewer flow direction at various locations across the collection system to confirm proposed sewer shed delineations and understand impact of the sewers upstream of proposed flow monitoring locations. The Engineer shall conduct field investigations to verify the suitability of each potential monitoring location. A.1.3 Flow Monitoring Services Prior to installing flow monitors, the Engineer will develop a now monitoring plan. The flow monitoring plan will include the preliminary monitoring sites selected from a review of the City's existing sewer maps. These sites will be based on a distribution of approximately 25,000 to 60,000 linear feet per flow monitor. Special attention areas or split now conditions may require additional flow monitors. Potential flow monitoring sites will be identified with consideration given to basin size, evidence of surcharging, overflow locations, projected maintenance activities, and other factors. Potential and alternate sites will be inspected and the site hydraulics evaluated. The Engineer shall conduct field investigations to verify the suitability of each potential monitoring location. The field investigations will verify sewer line interconnectivity and sewer flow direction in various locations across the collection system and in the proposed meter locations. The Engineer shall prepare a site investigation sheet for each selected site and shall submit to the CITY OF SOUTHLAKE. After approval of the recommended sites, the Engineer shall install and maintain the meters for Scope of Services— Southlake Page 1 of 5 a 60-day period. The Engineer shall also select rain gauge monitoring sites and install continuous recording rain gauges. Flow monitoring will be performed utilizing ADS or equal monitors capable of measuring both depth and velocity of flow. Tipping bucket gauges will be installed to obtain rainfall distribution data. A total of twenty (20) Flow Meters and five (5) tipping bucket rain gauges are proposed for the study. A.1.4 Flow Data Management During the flow monitoring study, flow data will be continually reviewed and analyzed in order to assess the accuracy and quality of the data. A.1.5 Flow Data Analysis A.1.5.1 Rainfall Relationship Adequate rainfall will be necessary to establish the relationship between peak inflow and rainfall intensity. This relationship will be used to determine the impact on the collection system during wet weather and high groundwater conditions. A correlation of flow and rainfall intensity will be made using the area-coefficient method of analysis. It is anticipated that a minimum of three storm events that do not cause surcharging of the collection system will be recorded during the 60-day monitoring period. Data from the continuously recording rainfall gauges will be used to establish the intensity of rainfall and duration for each storm event. The Thiessen Method for rainfall distribution analysis will be used. For each monitoring site, data developed as part of the analysis will include: - Average Dry Weather Diurnal Curve Flows for weekdays and weekends - Rainfall /Wet Weather Wastewater Flow Correlations for selected storm events during the monitoring period - Design peak inflow rate at the design storm event - Capacity analysis at the monitoring sites A.1.5.2 Based on the flow data analysis the various basins will be ranked according to their inflow contribution and infiltration contribution. The I&I ratings shall be used to develop a prioritization for each basin. Using the various rankings, the ENGINEER shall provide the CITY OF SOUTBLAKE with a recommendation for the basins in which to perform SSES activities. A.1.5.3 Incorporate flow analysis and flow projections will be summarized in a Technical Memorandum and submitted to the CITY OF SOUTBLAKE for review. Scope of Services— Southlake Page 2 of 5 SSES Field Investigation proposed for Field Investigation Work will consist of smoke testing, dye water flooding and data analysis. A.2.1 Project Administration The Engineer shall coordinate the overall work of the project to include all field inspections, engineering analysis. The Engineer shall provide monthly progress reports that will show the percent completion of each task. A bi-monthly progress meeting with the CITY OF SOUTHLAKE will be conducted. A.2.2 Public Information Program The Engineer shall conduct a public notification program prior to the field inspections in order to minimize potential alarm over the presence of field personnel in backyards and over the potential for entry of test smoke into the various premises. A.2.2.1 The ENGINEER will complete press releases to submit to the CITY OF SOUTHLAKE, hold informational meetings, and coordinate with CITY OF SOUTHLAKE's staff. A.2.2.2 Notification will be given to the CITY OF SOUTHLAKE, building owners, and residents by the distribution of door hangers at least 48 hours prior to commencing smoke testing activities. The local fire department, police department, emergency vehicle services (EMSA) and the CITY OF SOUTHLAKE staff will be notified each day prior to tests through the use of facsimile machines/E-Mail. A.2.2.3 Special coordination with property managers will be necessary for hospitals, medical offices, banks, government buildings, and other large commercial facilities. A.2.2.4 The ENGINEER will respond to all telephone calls by building owners or occupants during all active phases of the project. A.2.3 Manhole Inspections—Not Proposed at this time A.2.4 Smoke Testing A.2.4.1 Smoke testing will be conducted using dual axial blowers. Smoke testing lengths shall be limited to one line segment between the upstream and downstream blower locations. Each 12-inch diameter and smaller segment shall be isolated by sandbagging. Smoke candles shall be used to generate smoke for the smoke testing. Segments totaling less than 500 feet may include straight through manholes. Smoke testing will be performed only during dry ground periods which are anticipated to be between July and September. A.2.4.2 Flags shall be placed at observed smoke locations and digital images shall be captured. All defects identified by smoke testing shall be flagged and photographed. Smoke defect locations shall be recorded on sketches or by obtaining GPS coordinates. All private sector smoke defect images shall be entered into the field Scope of Services— Southlake Page 3 of 5 inspection database. A.2.4.3 Main line defects and service lateral defects shall be carefully scrutinized to ensure that a conservative determination of public vs. private side defects is made. If necessary the line shall be earmarked for television inspection. A.2.4.4 During the smoke testing, each building in the vicinity of the line segment will be observed for evidence of illegal or illicit connections, or other defects. All such defects shall be noted on the smoke test form. Where suspect defects are identified but are not confirmed by the smoke test, the building address, type, and suspected defect shall be noted. All such buildings will be submitted to the CITY OF SOUTHLAKE as candidates for a detailed building inspection or dyed water flooding. Upon review and approval by the CITY OF SOUTHLAKE these buildings will be subsequently inspected by the Engineer. A.2.5 Dye Water Flooding A.2.5.1 Line segments requiring dye water testing will be identified on the basis of smoke test results. Prior to initiating dye water testing, a list of line segments recommended for dye water testing will be provided to the CITY OF SOUTHLAKE for review and approval. The line segments on the list will be annotated as to the priority and reason for recommendation. It is anticipated that dyed water flooding of suspected downspouts, drains, and storm sewers in the downtown area may be performed in lieu of smoke testing. A.2.5.2 Dyed water flooding shall be conducted at selected locations prior to televised inspection to verify the existence of inflow and infiltration sources. Dye testing will also be conducted concurrently with television inspections on those line segments approved by the CITY OF SOUTHLAKE for dye testing. A.2.5.3 The dye water will be induced into the line by flooding storm sewers and drainage ditches. Sufficient time will be allowed for the source to activate, at which time the television inspection equipment will be introduced into the line segment. A.2.6 Cleaning and Television Inspection—Not Proposed at this time A.2.7 Data Management/ Quality Assurance A.2.7.1 Each field inspection form will be reviewed to ensure that the field data is complete and free from obvious errors or inaccuracies. Smoke test photos will be reviewed to ensure that background reference features appear in the photo. Dyed water forms will be reviewed to ensure that they correlate with the CITY OF SOUTHLAKE's atlas. Data entry will be performed concurrently with the field inspections to ensure that errors are identified, addressed, and corrected as soon after the inspection was performed as possible. A.2.7.2 All smoke testing, dyed water and any other observed defects shall be captured with a digital camera and loaded on to a CD or Flash drive for delivery to the CITY OF SOUTHLAKE. Scope of Services— Southlake Page 4 of 5 A.2.7.3 Discrepancies between the CITY OF SOUTHLAKE's sewer atlas and actual field conditions will be recorded on standard forms and periodically delivered to the CITY OF SOUTHLAKE. A.2.8 Defect Analysis and Technical Memorandum: At the conclusion of the field investigation services, an engineering analysis of field survey data shall be performed to develop recommendations for prioritizing UI source repairs. A description of field investigations, engineering analysis, and recommended action to reduce I/I will be included. -- END -- Scope of Services— Southlake Page 5 of 5