TECHNICAL MEMORANDUM

Transcription

1 Attachment 1 TECHNICAL MEMORANDUM DATE: January 8, 2015 TO: Richard Chiu Jr., P.E. City Engineer and Public Works Director FROM: Vivian W. Housen, P.E., RCE No SUBJECT: In July 2014, the Town of Los Altos Hills contracted with V. W. Housen & Associates (VWHA) to conduct an assessment of the sewer collection system and its management, and to review and help guide early activities that are underway by the Town s new collection system maintenance contractor, West Bay Sanitary District (West Bay). This Technical Memorandum (TM) describes the work completed for this assessment, and presents findings and recommendations. The following Sections comprise this report: Executive Summary Introduction and Background Supporting Documents and Data Assessments Findings and Recommendations EXECUTIVE SUMMARY The Town of Los Altos Hills manages over 50 miles of sanitary sewer collection system pipelines and associated facilities as shown in Figure 1-1. The system has eight separate outlets to the City of Los Altos and Palo Alto sewer systems. The Town uses contract forces to maintain the system, and in 2014, entered into a new contract with West Bay Sanitary District for this work. West Bay also manages and maintains a publicly-owned sewer collection system that serves the City of Menlo Park and surrounding communities. The observations, findings, and recommendations summarized in the Executive Summary are described in further detail within this Technical Memorandum. ES-1 Sewer System Management Plan and Capacity Assurance Planning The State and Regional Water Quality Control Boards rely on two key documents to define sewer system management needs. The Sewer System Management Plan (SSMP) describes the Town s objectives and systems for management and maintenance of the sewer system. This document is different than the similarly-named Sewer Master Plan. The SSMP must follow a prescribed outline established by the State Board. The State Board requirements were most recently amended in late 2013.

2 Page 2 The Town s SSMP was most recently updated in January 2013, prior to release of the 2013 State Board updated requirements. Since the SSMP is designed to be a working document, it is important for the Town to have a document that meets the most recent regulatory requirements and describes current operations. Town staff are completing needed updates to the SSMP, and will bring a new document to the Council for review and action in early The updates will address: 2013 State Board requirements, including new sanitary sewer overflow (SSO) reporting requirements Updated Overflow Emergency Response Plan Additional detail on current operations, maintenance, and sewer management activities The Regional and State Boards rely upon a second document, the Sewer Master Plan, to define capacity needs. The Town developed a Master Plan in 2004 that was based on a simplified flow analysis using limited data. The 2004 Master Plan is outdated and does not fulfill the requirements of SSMP Element 8 Capacity Assurance. Developing an updated hydraulic model and Master Plan should be a priority for the Town. Master Plan recommendations improve when the underlying data is complete and reliable. The cost involved in developing a comprehensive and complete document is usually recovered many times over through savings gained through avoided infrastructure costs. It is recommended that Master Plan development follow a multi-step process that includes the following components. Trunk sewer data collection (manhole locations and elevations, pipe depths) Comprehensive dry and wet weather flow data Hydraulic model development, and calibration of this computerized model to observed flows Flow analysis for existing and future conditions, under a design storm event. The analysis would not only identify capacity requirements, but would inform decisions related to the best location for new connections to the existing system. A rehabilitation component that can be addressed in the Master Plan, or separately through the Town s asset management program ES-2 Computerized Management and Mapping Tools The Town utilizes two computerized tools, the Computerized Maintenance Management System (CMMS) and Geographic Information System (GIS) maps, to assist in sewer system management. Data from both tools were reasonably complete, and were successfully migrated from the pre-existing systems to the systems in use by West Bay (Lucity software for CMMS and GIS for system maps). The Town has access to the Lucity database through a password-protected website. During the migration of data, and then afterwards while using these tools to complete field activities, West Bay identified a number of recommended updates and improvements. These recommendations are under discussion between West Bay and Town staff, and include a number of map corrections to more accurately represent field conditions. After the initial corrections are completed, it is anticipated that the need for future changes will be less.

3 Page 3 In addition to correcting map information, West Bay is augmenting the CMMS database to include more information on maintenance activities, and to document hot spot cleaning and other specialty activities. No action by the Town is required related to ongoing updates to the CMMS. ES-3 Cleaning And CCTV Inspection Programs West Bay began cleaning system pipes in the northwest portion of the service area in September 2014, and cleaned over 7 miles of pipe by the end of October Crews are now cleaning high priority sewers that are located on the west side of Highway 280, south of Arastradero Road. Both of these areas were identified as problem areas by the prior contractor. Figure 3-3 summarizes the cleaning program to date. The West Bay pipeline cleaning schedule was developed using the existing cleaning program, which addresses the entire system annually, as a basis. However, the previous cleaning program was not successful in controlling 2014 sanitary sewer overflows (SSOs), as shown in Figure ES- 1 (also presented as Figure 3-4 in this TM). Table ES-1. SSO Trends by Year and Cause Number of SSOs (to Oct 2014) 0 SSO Cause West Bay has improved the cleaning program through an enhanced hot spot cleaning program, which focuses and accelerates cleaning activities in known problem areas. The West Bay cleaning program has provided information on the effectiveness of the Town s root foaming program, which occurred from May through July The root foaming program involved the application of chemical root control agent within approximately 80 percent of the system collector pipelines, as shown in Figure 3-2. In addition to pipe cleaning, the Town s maintenance contractors have been required to conduct limited closed circuit television (CCTV) inspection of the system. In early 2014, the Town s

4 Page 4 previous maintenance contractor, Veolia, provided pipeline inspection data for approximately 28,000 lineal feet or ten percent of the system. Since August 2014, West Bay has inspected 21,000 lineal feet of pipe, which includes 2,370 lineal feet of pipe that was inspected previously. CCTV progress is shown in Figure 3-7. Veolia and West Bay each reviewed CCTV inspection results and provided recommendations for rehabilitation. West Bay focused their recommendations on pipes with high structural defect scores, whereas the Veolia recommendations appear to include a higher number of pipes with moderate structural defects. Based on the limited number of recommendations that were reviewed, it seems more appropriate to follow the approach that was used by West Bay. Review of data by VWHA from the 21,000 lineal feet of pipe inspected by West Bay resulted in the following recommendations for pipeline rehabilitation: Priority 1: Repair six defects with very high structural defect scores. Estimated cost is $25,000 Priority 2: Repair 13 defects with high structural defect scores. Many of these defects comprise large joint offsets. Estimated cost is $70,000 Priority 3: Repair 7 defects with moderate structural defect scores. Estimated cost is $35,000 A third company, Mark Thomas & Company, has completed an additional 9,000 lineal feet of pipeline inspection. Data from these inspections are under review, and may result in additional recommendations for pipeline repair. In summary, cleaning and CCTV inspection activities have identified the following concerns that will be addressed through the current West Bay maintenance program: The Town has over 2,800 lineal feet of pipe that have not been cleaned in several years and must be prioritized for near-term cleaning The Town has issues with root intrusion. Systematic control of root growth through cleaning and chemical root control should address this issue over time. Development of a strategic and dynamic hot spot program is critical to the success of this approach. The initial benefit gained through chemical root control was not optimum, since most pipes could not be cleaned before the product was applied. One or more additional cycles should be completed in order to fully benefit from this program. CCTV data is not available for all sewer pipes. This information will be helpful in planning maintenance and rehabilitation activities. CCTV inspection of currently uninspected pipes within five years is highly recommended. West Bay has also inspected the Town s pump stations, and provides regular maintenance. Inspection records have identified routine maintenance improvements, but no major mechanical or electrical issues. ES-4 Cost of Service, Budget, and Staffing The FY budget includes $2.54 million for sewer system operations and maintenance. This budget includes the following:

5 Page 5 $2.02 million for operations and maintenance $818k for conveyance and treatment costss that are paid to the Cities of Los Altos and Palo Alto $165k for engineering and management salaries and benefits $1.04 million for other expenses $515k for capital improvements The Town utilizes less than one full-time Senior Engineer to manage the sewer system maintenance contractor, conduct development-related plan checks, and review sewer mainline extensions. The Senior Engineer is supported by as-needed consultant support. This level of staffing is sufficient to manage the Town s sewer operations. However, staff augmentation will be required during periods when development or administrative activities increase, during vacation periods, or on matters where specific sewer-related expertise is required. It is recommendedd that the Town allocate budget for 0.5 to 1 FTE of as-needed support. In 2014, the Town entered into a contract with West Bay for an amount not to exceed $300,000 for sewer system maintenance and SSO response. The West Bay scope is separate from other O&M contracts for activities such as chemical root control, supplemental CCTV inspection, and maintenance-related repairs. The Town s available budget of $1.04 million appears more than sufficient to fund necessary staff augmentation, the Westt Bay contract, and other O&M needs on a long-term basis. However, maintenance costs will likely be higher than average in the next five years in order to allow the Town to address known maintenance issues. For example, increased near-term maintenance costs should be expected in order to control the Town s current root intrusion issues. Also, CCTV inspection of the entire system is recommendedd in the next five years. Inspection results will likely identify a large number of near-term spot repairs that are currently unknown to the Town. The Town s capital budget appears low for system size. The Regional Board recently announced its intention to review sewer system capital improvemen nt programs, and to expect a two percent annual replacement rate for agencies with aging sewer systems. In order to replace two percent of system annually in the near-term, the Town should budget approximately $1 million annually for pipeline improvements, and plan additional budget for pump station and system planning needs. It is anticipated that this annual budget can be reduced after five or more years, as the Town eventually transitions back to a 100-year lifecycle replacement program. ES-5 SUMMARY OF FINDINGS AND RECOMMENDATIONS Table ES-1 on the following page provides a summary of the findings and recommendations that are discussed in this TM. This Table is presented in similar form as Table 4-1.

6 Page 6 Table ES-1. Summary of Recommendations Topic Recommended Actions Estimated Cost Sewer System Management Plan Correct the SSMP format and incorporate needed changes to the SSMP. Update the document to reflect other recommendations and actions that result from this assessment. Update the bi-annual audit. Consider obtaining an external audit in lieu of a self-audit. Re-adopt the updated SSMP as soon as practical Capacity Establish a contracting mechanism to enable collection of flow Assurance data during the wet weather season Update the hydraulic model and Master Plan using information from the updated GIS, updated buildout projections, comprehensive and reliable flow data, and a fully dynamic, computerized hydraulic modeling tool Consider how and where parcels that are currently on septic systems should connect to the existing system. Formalize and enforce this strategy as a standard requirement of each conversion. System Data Develop a temporary workaround plan for addressing map inconsistencies in the field Conduct a 6-month review of the Lucity CMMS and O&M activities Develop a plan to collect and correct GIS-related issues as they are identified Develop a strategy for collecting manhole elevation data, depths to pipe invert, and to confirm inlet and outlet pipe diameters where visible during maintenance operations, and to add this information to the GIS database System Maintenance Rehabilitation and Replacement Clean all pipes that have not been cleaned within the past 12 months Formalize hot spot cleaning program, and develop a Standard Operating Procedure to manage this program Develop plan for 2 nd round of chemical root control within the next two years Develop system-wide CCTV approach Develop a prioritized near-term rehabilitation strategy that reduces risk through consideration of likelihood and consequence of failure Cost of Service Review capital and operating budgets and update as required to address future changes to the Town s sewer system management and maintenance approach. Most activities to be completed by staff. Cost for external audit is $5,000. $70k for flow monitoring; $50k for data collection; $250k for hydraulic model and master plan. $5,000 for workaround document; $20,000 for midyear GIS update; $10,000 for midyear Lucity and O&M review. $10,000 to develop hot spot cleaning program manual & CCTV inspection approach; $5,000 to define Year 2 root control program. $20,000 to develop initial priorities considering CCTV results and risk To be completed by staff

7 Page 7 SEWER COLLECTION SYSTEM ASSESSMENT The following sections provide additional information to support the findings and recommendations of the Town of Los Altos Hills sewer collection system assessment. 1.0 INTRODUCTION AND BACKGROUND The Town of Los Altos Hills (Town) manages a sanitary sewer collection system that comprises 53 miles of gravity sewer pipelines 1, 4 miles of pressurized forcemains, and 2 pumping stations. Wastewater is conveyed through the Cities of Los Altos and Palo Alto to the Palo Alto Regional Water Quality Control Plant for treatment. The Town s collection system is shown in Figure 1-1. The sewer system is divided into seven sewersheds or Branches, as shown in Figure 1-2. Each Branch comprises a collection of local sewer pipelines that convey flow to a larger trunk line. The Town has historically contracted with outside forces for sewer system maintenance. Over the past years, this service has been provided by Collection System Maintenance Services, Able Underground, and more recently, Veolia Water. In 2014, the Town entered into a contract with West Bay Sanitary District to clean, inspect, and recommend improvements to the sewer collection system. As part of their scope, West Bay is completing a separate assessment of sewer system data, condition, and needs. To assure consistency, the findings and recommendations that are provided in this TM were discussed with West Bay. 2.0 SUPPORTING DOCUMENTS AND DATA The following information was reviewed in preparation for the sewer collection system assessment. Each document is described in additional detail in Section 3.0, Assessments. Sewer System Management Plan, 2014 Audit, and recent prior audits 2004 Sanitary Sewer System Master Plan Computerized System Management Data & Historical Documents Computerized Maintenance Management System Geographic Information System (GIS) Map Data Example Veolia Monthly Reports and CCTV Summary Report Town Chemical Root Control Locations West Bay Pipeline Cleaning and CCTV Inspection Results, and Repair Recommendations Rehabilitation and Repair Planning Budget and Staffing Related to Sewer Collection System SSO Data from , as Obtained Through CIWQS Information on Planned and Completed CIP Projects from approximately 2010 to Current 1 Gravity and forcemain lengths are as reported by the Town to the Regional Water Quality Control Board, through the California Integrated Water Quality System (CIWQS)

8 Page ASSESSMENTS The sequence of assessments followed the outline shown in Section 2.0. Each section below includes recommended actions. Section 4.0 compiles these actions into a single summary of Findings and Recommendations. 3.1 Sewer System Management Plan Sewer collection system agencies throughout the State with greater than one mile of public sewers are required to have developed a Sewer System Management Plan that meets specific requirements established by the Regional and State Water Boards. The Regional Water Quality Control Board requirements were released in 2005, over one year before release of the State requirements. The Regional and State requirements were slightly different in required content and very different in required organization. Due to the lag between Regional and State mandates, many sewer collection system agencies in the San Francisco Bay Region, including the Town, originally followed the Regional Board recommendations and format. State Water Resources Control Board (SWRCB) Order No DWQ, also known as the Statewide Waste Discharge Requirements or WDR, requires the Town to describe its processes related to eleven elements of sewer system management. Several requirements of the Statewide WDR were amended or augmented by Order No EXEC, which is referenced as the Amended Monitoring and Reporting Program or MRP. After the release of the Amended MRP, the Regional Board unofficially advised agencies to follow the Statewide WDR outline in lieu of the 2005 Regional Board guidelines. This advice was formalized through a written notice that was issued by the SWRCB via in late The Town is required to complete and adopt a 5-year update of the SSMP that addresses the requirements of the Amended MRP. The Town s SSMP is descriptive, and follows the 2005 Regional Board SSMP Development Guide outline. The SSMP was most recently revised and readopted in January 2013, prior to release of the Amended MRP. Town staff and Regional Board staff met to discuss the need for further changes, and agreed in principle to include these items as internal markups to the SSMP until the next regular update. In order to remain current with recent changes to the Statewide WDR, the document requires further updating in 2015 to include key components of the Amended MRP, including: 1) new SSO categories; 2) a Water Quality Monitoring Plan; and 3) plan for a required SSO Technical Report. Further, the bi-annual audit, which was completed by Town staff in March 2014, should be amended to include a plan to address these changes. When the SSMP update occurs, it is recommended that the Town incorporate other changes to specific Elements of the SSMP that have been discussed with staff. For example, a key component of the SSMP is the Overflow Emergency Response Plan (OERP), which is included as Element 4 in the current SSMP, and is defined as Element 6 in the Statewide WDR. The OERP must very closely reflect emergency response communications and actions, including the manner in which customer calls are conveyed to West Bay. The Town s OERP was developed by an outside consultant prior to the onset of the West Bay sewer maintenance contract. West Bay has developed, for its own agency, an OERP that is customized to its sewer overflow response

9 Page 9 activities and is different than the Town s OERP. The West Bay OERP has been reviewed by the EPA, San Francisco Baykeeper, environmental legal counsel, and outside wastewater advisors. It is important that the Town resolve the differences between the response actions that are described in the current OERP and those actions in use by West Bay. A second key area requiring update involves the description of system maintenance activities such as cleaning and CCTV inspection. As discussed further in this TM, changes are in process related to the Town s sewer maintenance strategies. The SSMP should reflect these changes, and also incorporate any new information that is identified through discussions and actions that result from this assessment. Recommended Action(s) Regarding SSMP Based on review of the Town s current SSMP, it is recommended that the Town take the following actions: Reformat the document to meet the requirements and format of the Statewide WDR and Amended MRP Incorporate changes to the SSMP that were discussed by VWHA and Town staff. In addition, update the document to reflect other recommendations and actions that result from this assessment. Update the bi-annual audit to document the changes that are made. Although not required, it is recommended that the Town consider obtaining an external audit in lieu of a selfaudit. Re-adopt the updated SSMP as soon as practical 3.2 Capacity Assurance (Sanitary Sewer Master Plan) In 2004, the Town contracted with HDR to develop a sewer collection system hydraulic model and Sanitary Sewer Master Plan (Master Plan). The Master Plan project included limited flow monitoring, development of a simplified spreadsheet flow model, evaluation of available capacity to convey peak wet weather flows, and development of a capital improvement plan. As part of the scope, HDR also evaluated sewer maintenance practices. The Master Plan concluded that improvements were not required to address 2004 flows, but are needed to accommodate buildout conditions. Buildout was defined in the Master Plan as providing sewer service to every undeveloped parcel and to every parcel that was on a septic system in The Master Plan concluded that capacity improvements needed for buildout would not be required for at least ten years, and would depend on the rate of buildout. The described level of buildout has not occurred between 2004 and the present. In preparation for the Master Plan, flow monitoring was conducted in four locations during a 2- week dry weather period during October One of the dry weather flow monitors was fouled for half of the monitoring period, yielding a single week of flow data. Additional flow monitoring was conducted in two locations during a 4-week wet weather period during February and March One of the two meters showed surcharge conditions during a sewer backup, which would have compromised data accuracy.

10 Page 10 Evaluation of 2002 Flow Monitoring Program The Master Plan describes the Town s service area as including seven separate sewersheds. Each sewershed includes a group of parcels and properties that flow to a common sewer trunk line. In addition, the Town s sewer trunk lines join the City of Los Altos and City of Palo Alto systems at eight outlets. In order to accurately assess flow characteristics within each sewershed and at each of the system outlets, it is important to install individual meters in as many of individual sewersheds as possible. Due to flow anomalies, the flow monitoring program collected reliable flow at three locations during dry weather and a single location during wet weather. The evaluation of dry weather flow is straightforward. As a result, it is possible to establish dry weather flow averages and daily flow patterns after collecting several weeks of flow data. However, quantification of wet weather flow is more complex. Wet weather flows within sewer pipes vary widely, and depend on a number of factors. Pipe steepness, condition, location, size, depth, and other characteristics all affect the volume and intensity of rainwater that enters sanitary sewers during wet weather events. Rainfall duration, volume, and intensity also impact wet weather sewer flows. Above all, wet weather sewer flows are usually underrepresented until the ground becomes saturated through multiple, consecutive rainfall events. It is unlikely that the wet weather data that was collected by a single reliable flowmeter over a 4- week period in February and March 2003 provided sufficient data to evaluate peak wet weather flow characteristics. Specifically, peak daily rainfall recorded during the wet weather flow monitoring period was 0.62 inches, which, in the context of hydraulic modeling, is not considered to be a significant rainfall event in the San Francisco Bay Area. Further, it is not clear that the recorded rainfall occurred during a period with full ground saturation from preceding storms (also described as antecedent rainfall). If the 2003 wet weather flow data was not sufficient for wet weather flow estimation, then flow predictions that would have been generated by the spreadsheet model using this data, as well as recommended capacity improvements, are not reliable. The Master Plan recognized that the flow monitoring program required more locations, and concluded that eight meters would be sufficient to collected necessary data. The Master Plan also uses general assumptions about peak wet weather flows in the absence of reliable wet weather flow data. VWHA reviewed system flow paths, and recommends that the City consider 8 to 10 meter locations for the next flow monitoring program, as shown in Figure 2-1. Collection of flow data that is sufficient for hydraulic model development and calibration is not a straightforward task. The most reliable data is available during substantial wet weather seasons, which do not occur every year. The most recent substantial wet weather season occurred during the winter of Rainfall and wet weather flow data that have been collected in the Bay Area since this time must be considered very carefully, as the information may not be appropriate for use in developing or updating hydraulic models. Sufficient wet weather events cannot be planned. Therefore, it would be prudent for the Town to secure an on-call flow monitoring consultant that is able to mobilize quickly and install flow meters during the current wet weather season. December rainfall was substantial, and

11 Page 11 consecutive storms would have contributed to ground saturation. If additional, similar rainfall events were to occur in 2015, they would most likely take place before the end of February. A proactive approach would be to pre-determine meter numbers, locations, durations, and associated costs, and then issue a contract that would only authorize meter installation as directed by the Town. Through this approach, the Town would only gather and pay for data if weather conditions are likely to create substantial sewer flows. As discussed above, between eight and 10 meters are recommended to collect sufficient wet weather data to update the hydraulic model. The meters should remain in place for a four-week period, which may extend to eight weeks. In addition, the Town should consider installing meters in at least eight locations for a two-week dry weather period. The estimated cost to install ten meters for eight weeks during wet weather, and eight meters for two additional weeks during dry weather, is $60,000 to $75,000. Hydraulic Modeling Approach The Town s hydraulic model was developed using a spreadsheet that included 140 pipe segments, which comprise less than eight percent of system pipes. If all of the Town s trunk sewers were modeled, this value is likely to increase to as much as 20 percent of the system. A single peaking factor of 10 was applied to the assigned dry weather flow for each pipe, in order to represent potential wet weather flows. It is unusual for all sewer basins to exhibit the same wet weather peaking characteristics, and possible that the assigned peaking factor is conservative (i.e. higher than actual) for some sewer basins. The Master Plan notes that a peaking factor was used in lieu of predicted wet weather flows due to the uncertainty of flow monitoring data. Based on the information reviewed, the Town s existing trunk lines were not fully represented, and the spreadsheet model was not calibrated to measured flows. Therefore, the existing hydraulic model cannot reliably predict capacity needs based on a designated design storm event. As a result, projected wet weather flows, and associated recommendations for capacity improvements, should only be considered estimates, and should not be relied upon for capital improvement planning. In addition to improving capacity-related planning criteria and data, the Town should consider updating its hydraulic modeling methodology. Since 2004, hydraulic modeling tools have substantially improved. Computerized hydraulic modeling software allows the representation of dynamic flows within sewer collection system pipes. Dynamic flow representation takes into account the momentum that is created by flow, and how this momentum affects other system flows. This approach is an improvement over the static, snapshot approach that is provided through a spreadsheet model, and should be used for future Master Plan updates. Recommended Action(s) Regarding Capacity Assurance It is recommended that the Town consider, in the near future, an update to the hydraulic model and Master Plan using information from the updated GIS, updated buildout projections, comprehensive and reliable flow data, and a fully dynamic, computerized hydraulic modeling tool. In preparation for this update, it is recommended that the Town consider a flow monitoring program in the near future, and as early as the wet weather season, with an objective of

12 Page 12 capturing significant wet weather flow data when it occurs, and summer period dry weather flows. This flow data will not only inform hydraulic model development, but can also help the Town to define and perhaps amend unit flow values that are in use by the Cities of Los Altos Hills and Palo Alto to assess conveyance and treatment costs. In addition to new flow data, the updated hydraulic model should include all trunk lines and any collector sewers that are known to have surcharge conditions during peak wet weather events. If the Town s 8-inch diameter pipelines comprise the trunk line system, then approximately 20 percent of system pipes or 371 pipe segments would be included in the hydraulic model network. In order to have improved confidence in model results, the Town should collect accurate manhole rim and pipe invert data for the modeled pipes and manholes. A portion of this work should be scheduled to occur at the same time as sewer cleaning and CCTV inspection. The cost for asset data collection will vary, but could be up to $50, In addition, the cost for a hydraulic model and Master Plan update is likely to be in the range of $200,000 to $250,000. The buildout condition, consisting primarily of conversions from septic to sewered parcels, did not occur as anticipated by the Master Plan. Since the location of new connections may affect system capacity, the Master Plan update should evaluate potential connection points and develop a buildout approach that has the least overall impact on system capacity. This strategy could then be formalized by the Town, and enforced as a standard requirement of each conversion. 3.3 Computerized Management Tools and Historical Documentation The Town utilizes two computerized tools, the Computerized Maintenance Management System (CMMS) and Geographic Information System (GIS) maps, to assist in sewer system management. Electronic data was migrated to West Bay s CMMS system and GIS database. This assessment reviews the quality and value of this and other data. Veolia Computerized Maintenance Management System Data In 2011, the Town s prior sewer maintenance contractor, Veolia, began development of a CMMS for the Town. The CMMS used InfoNet, a widely-known computer software package, to store collected system data and generate work orders for repairs, cleaning, and inspection. The data was exported to a Microsoft Access database at the conclusion of the Veolia contract. The following data was extracted from the Veolia CMMS database and reviewed for this assessment: CCTV inspection locations, dates, and results Cleaning locations, dates, and results SSO information Information on customer calls, typically related to residential backups, public and private SSOs, and odors 2 West Bay is interested in discussing potential cost-sharing of equipment needed to obtain GPS coordinates for manholes.

13 Page 13 The Veolia CMMS database contains relevant and current system information, and provides a good foundation for future data collection. West Bay successfully migrated the existing data from InfoNet to a new CMMS software named Lucity, and has made the Lucity system available to Town staff through a password-protected internet connection. Examples of the information that was stored in the Veolia CMMS are included in relevant sections, later in this TM. Geographic Information System Data Veolia used their CMMS software as a mapping tool for Town s system. This information was exported as a Geographic Information System (GIS) database at the conclusion of the Veolia contract. The GIS database includes the following system attributes: Structure identification numbers and locations, including manhole ID numbers, and labeling for cleanouts, junctions, and pump stations Pipelines, defined from manhole to manhole. Pipeline data includes material, diameter, length, sewer basin, and the location within a street or easement. GIS maps are dynamic documents, and it is common for updates to be required as new field information is discovered. In this regard, the Town has received feedback from West Bay regarding sewer asset information that requires updates in the current GIS database. These changes range from mislabeled structures, to missing structures and misplaced pipelines. The issues appear to occur throughout the system, and it may not be efficient to address each issue as it is identified. It is recommended that the Town and West Bay develop a process to track and address these needs over time in a cost effective manner. West Bay has developed conventional sewer system map books using the available GIS data. During this process, it has become apparent that some manholes fall outside of the boundaries of what should be their assigned map page. This issue is difficult to manage while in the field, since asset numbering typically tells field crews where to find the asset on their paper or electronic maps. A temporary workaround can be implemented to assist in the use of current maps. However, until the issue is resolved, West Bay anticipates that maintenance inefficiencies related to mapping errors will not be fully resolved. Therefore, this issue should be corrected as soon as practical through future map updates. An example grid page from the Town s GIS sewer maps is included on Figure 3-1. This figure shows how sewer manholes that are included in Grid B are mislabeled with Manhole IDs that begin with the letter C. Veolia Monthly Reports and CCTV Summary Report Veolia was required to provide reports to the Town summarizing activities for each month. VWHA reviewed three example monthly reports to understand their content and level of detail. The reports included the following: Lift station activities Sanitary system activities including cleaning activities (footage within streets and easements), service calls, and CCTV inspections completed (length and date)

14 Page 14 Veolia also provided a summary CCTV inspection report at the conclusion of their contracted CCTV inspection task, which included records for 28,000 lineal feet of inspected pipe, or approximately ten percent of the gravity collection system. The report provided two maps showing televised pipe segments by location and overall condition rating, a summary table showing the footage of pipelines in each PACP defect category, and an appendix listing each pipe segment that was inspected and its PACP condition. The report also included a table that listed eight pipelines requiring repair. These pipes are included in Table 3-1 on the following page. The data that was provided in these reports was not sufficient for VWHA to evaluate the quality or quantity of work that was completed by Veolia. Aside from the pipeline recommendations, the reports did not include other discussions of key issues, concerns, or needed actions. The recent CCTV inspection effort completed by West Bay provided repeat inspections for fourteen of the pipe segments that were previously inspected by Veolia, including two of the pipe segments shown in Table 3-1. The inspections results for approximately half of the pipe segments were consistent between the two inspections. Table 3-1. Veolia Pipeline Rehabilitation Recommendations Pipe ID CMH1020_CMH1021 EMH1030_EMH1028 AMH1021_AMH1020 BMH1044_BMH1054 BMH1031_BMH1030 BMH1032_BMH1031 GMH1041_GMH1042 HMH1099_HMH1032 Recommendation Point repair at joint offset Point repairs at 3 broken pipe locations Point repairs at joint offset and pipe breakthrough Point repair Point repairs at 2 pipe breaks Manhole rehabilitation Point repair at 2 pipe breaks Point repairs 2 pipe breaks The two pipe segments from Table 3.1 that were reinspected include AMH1021-AMH1020 and GMH1080-GMH1083. West Bay confirmed that two point repairs are required for segment AMH1021-AMH1020. However, the repairs are required to correct two large Grade 5 joint offsets. By comparison, Veolia recommended repair of one joint offset and one pipe break. Similarly, the West Bay inspection shows the need for one point repair on segment GMH1080- GHM1083 to repair a large Grade 5 joint offset. By comparison, Veolia recommended repair of two of the Grade 3 defects. Although this comparison was completed on a relatively small number of pipe segments, it is recommended that Town develop new rehabilitation recommendations based on the West Bay inspection results. Recommendations provided by West Bay and supplemented by VWHA are discussed later in this TM, and shown in Table 3-2.

15 Page 15 Additional Maintenance Data From May through July 2014, approximately 80 percent of the system, including nearly all pipes within easements, received chemical root control treatment, as shown on Figure 3-2. Also, between August and October 2014, West Bay collected approximately four miles (eight percent) of additional CCTV inspection data and 7.2 miles (fourteen percent) of additional cleaning results for the pipes shown on Figure 3-3. This new information has proved to be very important in assessing the effectiveness of prior sewer maintenance activities, as described further in Section 3.4. To supplement this information, between April and August 2014, approximately 9,000 lineal feet or three percent of additional CCTV inspection was conducted by Mark Thomas & Company (MTCO). MTCO provided inspection videos to West Bay, and in late November 2014, also provided an inspection database to the Town. VWHA is in the process of evaluating the MTCO information and will provide an amendment to this TM summarizing results. West Bay Cleaning and CCTV Inspection Data West Bay began maintaining the Town s sewer system in August Early activities focused on CCTV inspection and pump station maintenance, whereas cleaning activities began in September Cleaning was deferred in order to allow chemical root control treatment, which was completed between May and July 2014, to take effect. The root control applicator advises that cleaning of pipes that receive chemical treatment should be deferred for approximately two months. Figure 3-3 shows the sewer pipelines that were cleaned by West Bay in September and October West Bay focused their initial cleaning and CCTV activities on areas with recorded SSOs. Concurrently, West Bay initiated a basin-wide cleaning program, beginning with Branch 1 as designated in the Town s GIS. Branch 1, also known as the Palo Alto 1 subbasin, includes the neighborhoods that include and are adjacent to Page Mill Road, south of Interstate 280. VWHA, the Town, and West Bay met in October 2014 to review West Bay s maintenance progress. During this meeting, West Bay reported on findings from various aspects of their cleaning and CCTV inspection program, and also described the near-term plan for future activities. The next basin to receive cleaning is Branch 2, which includes the La Cresta Drive neighborhood south of Arastradero Road and east of Interstate 280. Branch 2, also known as the Palo Alto 2 subbasin, includes a substantial portion of the root-related SSOs and customer calls that have occurred since The extended plan for system maintenance is under development, and will benefit from results gained from cleaning and inspection activities within Branches 1 and 2. Based on combined results of cleaning and CCTV inspection to date, West Bay identified 10 pipes that require follow up actions, including pipe-patch repairs using cured-in-place pipe liner, and open trench spot repairs. These pipes are listed in Table 3-2 on the following page. VWHA conducted a separate assessment of the CCTV data, and recommends additional repairs, as noted in Table 3-2.

16 Page 16 The estimated cost for the repairs shown in Table 3.2 is $130,000, to be phased over five years. This amount includes $25,000 for Priority 1 repairs, $70,000 for Priority 2 repairs, and $35,000 for Priority 3 repairs. Table 3-2. West Bay Pipeline Rehabilitation Recommendations Pipe ID WBSD Recommendation VWHA Supplemental Recommendation BCO1002_BH1007 Pipe Patch (i.e., pipe liner) Priority 1: One Grade 4 hole with soil visible EMH1057_EMH1066 None Priority 1: Open trench repair 1 Grade 5 joint separation KMH1075_KMH1074 Pipe Patch at 2 locations Priority 1: Pipe Patch 1 Grade 5 spiral fracture. Remaining defects are Grade 3. OMH1042_OMH1044 Open trench spot repair at 2 locations Priority 1: One Grade 5 break and One Grade 4 break DMH1041-DMH1040 None Priority 1: Pipe Patch 1 Grade 5 spiral fracture AMH1010-AMH1009 None Priority 2: Open trench repair 1 Grade 5 joint offset AMH1021-AMH1020 None Priority 2:Open trench repair 2 Grade 5 joint offsets BMH1051-BH1052 None Priority 2: Open trench repair 1 Grade 5 joint offset EMH1154-EMH1176 None Priority 2: Open trench repair 1 Grade 5 joint offset EMH1160-EMH1159 None Priority 2: Open trench repair 1 Grade 5 joint offset GMH1079-GMH1080 None Priority 2: Open trench repair 1 Grade 5 joint offset GMH1080-GMH1083 None Priority 2: Open trench repair 1 Grade 5 joint offset HMH1112_HMH1113 Pipe Patch at 2 locations Priority 2: Open trench repair 1 Grade 5 joint offset. Remaining breaks are Grade 3. KMH1048-KMH1049 None Priority 2: Open trench repair 1 Grade 5 joint offset KMH1051-KMH1052 None Priority 2: Open trench repair 1 Grade 5 joint offset KMH1088-KMH1087 None Priority 2: Open trench repair 2 Grade 5 joint offsets EMH1083_EMH1082 Pipe Patch Priority 3: Two Grade 3 broken pipe sections EMH1085_EMH1084 Pipe Patch Priority 3: One Grade 3 pipe break KMH1045_KMH1046 Pipe Patch at 2 locations Priority 3: Two Grade 3 pipe breaks/holes KMH1052_KMH1079 Open trench spot repair Priority 3: One Grade 3 pipe break KMH1078_KMH1077 Pipe Patch Priority 3: One Grade 3 pipe break OMH1101_OMH1100 Pipe Patch Priority 3: Review with West Bay. Defects are all Grade 3 and below. Recommended Action(s) Regarding System Data It appears that the Town s CMMS data was successfully imported into Lucity, and that Lucity is in full use as a component of West Bay s sewer maintenance strategy. There are no recommended actions related to the use of or content maintained in the Lucity CMMS at this time. However, it is recommended that the Town utilize the on-line connection to Lucity as much as possible in the next six months, and conduct a review of the Lucity CMMS at the end of this period, to confirm that data is collected and stored in a manner that is acceptable and useful to Town staff.

17 Page 17 The current GIS database is sufficient to support sewer maintenance and planning activities. However, there are a number of changes and corrections to the GIS database that have been identified, and will continue to be identified through ongoing maintenance activities. A plan should be developed between the Town and West Bay to address these issues over time. Also, as pertains to the GIS, and as described under the prior discussion related to Capacity Assurance, as pipes are cleaned and inspected, it would be prudent for the Town to collect manhole elevation data, depths to pipe invert, and to confirm inlet and outlet pipe diameters where visible. By adding this information to the asset inventory, the Town will be better prepared to conduct future activities such as CIP planning and system hydraulic modeling. 3.4 Existing and Proposed Maintenance Practices and Priorities Data available through the CMMS and GIS, and through more recent system maintenance activities, have highlighted a number of items that should be considered by the Town and West Bay as they move forward with a revised strategy for sewer system management. These items are categorized as follows: Sanitary Sewer Overflows Follow-Up Chemical Root Control Sewer Cleaning Activities Closed Circuit Television Inspection and PACP Rating Rehabilitation and Replacement Sanitary Sewer Overflow Follow-Up Figure 3-4 on the following page shows Sanitary Sewer Overflow (SSO) trends by year and by cause, as reported by the Town to the SWRCB since The information is available through the Veolia CMMS, and also through the SWRCB Integrated Water Quality System (CIWQS) public website. The predominant cause of SSOs has been root intrusion. As shown in Figure 3-4, the total number of SSOs decreased every year until However, in 2014, the number of root-related SSOs increased. The 2014 data shown in Figure 3-4 represents data for a partial year ending October 15, The increase in root-related SSOs may indicate an issue with prior maintenance practices, degradation of pipe condition, or a combination of the two factors. In addition, in 2014, many agencies have reported that root growth increased as a result of drought conditions. The decrease in available groundwater has reportedly led to more aggressive root growth through joints in sanitary sewers.

18 Page 18 Figure 3-4. Los Altos Hills SSO Trends Number of SSOs (to Oct 2014) 0 SSO Cause Figure 3-5 shows the locations of the Town s SSOs by cause, and also shows customer complaints that were received by Veolia between 2011 and Cleaning and/or CCTV inspection CMMS records do not show scheduled follow-up cleaning or CCTV at many of the SSO locations. However, Veolia maintained a separate hot spot list that is included as part of the SSMP. Hot spot cleaning activity is also described in InfoNet CMMS documentation through handwritten notes. West Bay has integrated the hot spot list into the Lucity CMMS, and is expanding and refining this list to reflect system needs that have been identified through recent maintenance activities. Chemical Root Control Between May and July 2014, the Town contracted with Duke s Root Control to apply chemical root control agent throughout the sewer system (Reference Figure 3-2). This program was initiated to provide rapid response to the increase in SSOs that occurred in the first quarter of Although an extended period is required to fully understand the benefit of chemical root control in terms of reducing SSOs, it should be noted that the Town reported 12 root-related SSOS during the first half of 2014, and has had two root-related SSOs to date in the latter half of the year. It is very likely that chemical root control measures contributed to this decrease in SSOs. Based on the number of SSOs that have occurred recently in the system, and the amount of roots that have penetrated the sewer system as determined through recent cleaning activities, the investment in chemical root control was a good decision for the Town. However, a large portion of the system had heavy root growth remaining prior to the application of the chemical root control agent, and some portions of the system will require subsequent cleaning and application of additional root control agent to complete the program.

19 Page 19 West Bay conducted CCTV inspection of a small portion of the system that received chemical root control. After reviewing the associated inspection videos, West Bay placed approximately 80 percent of the inspected pipes on a high frequency or hot spot list due to the continued presence of roots. By monitoring these locations, the Town and West Bay can use the rate of root regrowth as one factor in determining locations that should receive reapplication of root control agent within the next two years. In the future, root control agent should be applied after heavy roots are removed from the pipe. In this way, the root control agent will find its way into tree roots that are penetrating through the pipe joints. When pre-cleaning does not occur, then the agent finds and kills a portion of the roots within the center of the pipe only. The Town should see a substantial improvement in root control effectiveness after the second round of application. Sewer Cleaning Activities Figure 3-6 shows sewer cleaning results obtained from the Veolia CMMS database. Prior to April 2014, pipes appear to have been cleaned on an annual basis; no pipes have more than one scheduled cleaning date in a calendar year 3. Although many pipes were cleaned every year, the data shows that over 2,800 lineal feet of pipe have not been cleaned since These pipes are shown in red on Figure 3-6, and are also listed in Table 3-3 on the following page. The current GIS database does not delineate between gravity and pressure or forcemain pipelines. Any pipes listed in Table 3-3 that serve as forcemains should be removed from this list by the Town or West Bay. Table 3-3. Pipes Without Documented Cleaning from 2011 to 2014 US MH ID DS MH ID Diameter Material Length Location AMH1032 AMH VCP Easement AMH1033 AMH VCP Easement DCO1006 DMH VCP Easement DMH1003 DMH n/a Easement DMH1071 DMH PVC Easement EMH1010 BMH VCP Easement EMH1011 EMH VCP Not identified EMH1012 BMH VCP Not identified GMH1005 GMH1005 n/a n/a 0 Street HCO9000 HMH PVC 110 Street HMH1023 HMH VCP Not identified HMH1096 HMH VCP Street IMH1025 IMH HDPE 31 Street KMH1097 KMH VCP 350 Street SMH1017 SMH PVC 300 Street 3 If hot spot cleaning occurred, this activity would have been monitored separately, outside of the Veolia CMMS database.

20 Page 20 CCTV Inspection and PACP Rating Figure 3-7 shows the pipelines that were inspected by Veolia and West Bay. Veolia inspected 105 pipe segments, representing 28,000 lineal feet of pipe in early Inspection results were provided to the Town at the end of their contract. Veolia reported that 18 of the inspected segments had at least one NASSCO PACP Structural Grade 5 defect. However, the accuracy of this CCTV data has been challenged by more recent CCTV inspection results obtained by West Bay. West Bay inspected 21,000 lineal feet of pipe through October 2014, including repeat inspections of 14 pipes comprising 2,370 lineal feet that were previously inspected by Veolia. West Bay reinspected these pipes in order to assure consistency in the application of NASSCO PACP standards. Approximately half of the re-inspected pipes received structural defect codes that were consistent with the Veolia data. The West Bay inspection results appear to more closely reflect NASSCO PACP standards, and should be used in lieu of the prior results to define future rehabilitation needs. West Bay is contracted to inspect 40,000 total lineal feet of pipe comprising 14 percent of the gravity system pipelines. When results from the West Bay CCTV program become available for review, it will be important to review and amend as necessary the projects and priorities that are listed in Table 3-2. Mark Thomas and Company has also recently completed inspection of 9,000 lineal feet of sewer pipe. West Bay received videos from these inspections, and the Town received the inspection database in late November This data is under review and will be summarized in an amendment to this TM. CCTV inspection is the most accurate method of evaluating system condition. CCTV inspection results to date indicate that the Town s sewer system is aging and in need of repair. CCTV inspection of the entire system within a 3- to 5-year period, with accelerated inspection of high risk areas within the next 12 to 18 months, is recommended to inform decisions related to repair and replacement. Without system-wide data, the Town will have difficulty establishing overall priorities for system replacement. Pump Station Maintenance Activities Pump station maintenance is a critical component of sewer system management. The potential for large system overflows is usually higher with a pump station failure as compared to pipeline failures. Since September 2014, West Bay has conducted weekly inspections of the O Keefe Court and Purissima pump stations. In addition, in August 2014, West Bay performed a more comprehensive annual maintenance inspection of the O Keefe Court pump station. Following this inspection, West Bay recommended several maintenance improvements. Earlier this year, the Town replaced two of the four existing aging pumps in the Purissima pump station to improve system reliability and outage response. To date, aside from routine maintenance needs, no issues of concern have been identified for the pump stations.

21 Page 21 Recommended Action(s) Related to Sewer System Maintenance Based on the information reviewed, following are recommendations related to sewer system maintenance: Clean pipes that do not have any cleaning information shown in the CMMS. It is likely that these pipes have not been cleaned in at least three years. Develop cleaning schedules that also maximize system data gained for the future hydraulic model update Formalize an initial hot spot cleaning program, and develop Standard Operating Procedures for adding and removing future lines from this program Conduct a peer review of West Bay cleaning results using post-cleaning CCTV data Use collected CCTV inspection data to identify pipes that would benefit from a second round of chemical root control within the next two years Review West Bay CCTV inspection results and utilize these results, and associated recommendations, to develop a prioritized near-term rehabilitation strategy that reduces risk through consideration of likelihood and consequence of failure Develop a system-wide CCTV approach and plan that obtains inspection data for the entire system within 3 to 5 years, and accelerates inspection of the highest risk areas in the first 12 to 18 months of the program Continue implementation of the pump station maintenance program 3.5 Rehabilitation and Replacement Planning The Town has completed two major pipeline projects, in addition to routine pipeline rehabilitation work. The first project, the Eastbrook Sewer project, eliminated an inverted siphon across a creek. The second project, the Pine Lane Sewer Main Diversion project, enabled the Town to bypass flows around the Los Altos Pump Station. The FY budget includes 13 additional projects that will collectively replace 1,425 lineal feet of pipe, or one half of one percent of the gravity system. The objective for the current fiscal year is to focus on repairs within easements, and to consider not only the worst defects, but other improvements that will reduce the level of maintenance required in these difficult-to access areas. For future budgeting efforts, the Town is considering the two lists of recommended repairs that were provided separately by Veolia and West Bay. These lists have been reviewed further in conjunction with the development of this TM. Following this review, VWHA expanded and prioritized the West Bay recommendations based on pipeline condition. As the Town s data library expands through additional CCTV inspection, future prioritization efforts should not only address known defects, but also be structured to reduce overall risk. Although CCTV and maintenance data can provide meaningful information on the likelihood of pipe failure, a riskbased approach also considers the consequence of failure when establishing priorities. The Town may find that by increasing the budget for several years in the early years of a long term asset management program, it can rapidly and substantially decrease risk.

22 Page Cost of Service, Budget, and Staffing The Town adopts an annual budget that includes a separate description of sewer-related charges. Sewer service charges pay for labor, capital expenses, sewer operations and maintenance, and the Town s share of wastewater treatment plant operations. A portion of the operations and maintenance revenue is provided as an allocation by the Town for overhead and administrative expenses. The Fiscal Year budget lists $2.54 million in total capital and operating expense, including $2.02 million for sewer operations and $515,000 in capital expenditures. Of the operating expense, $817,770 is allocated to sewer treatment and conveyance costs that are payable to the Cities of Los Altos and Palo Alto, and $165,391 is required to cover engineering and management salaries and benefits. As a result, $1,041,933 is allocated for sewer collection system labor, operations, and maintenance. The Town utilizes less than one full-time Senior Engineer to manage the sewer system maintenance contractor, conduct development-related plan checks, and review sewer mainline extensions. The Senior Engineer does not receive administrative support. The Town has requested an opinion on whether this level of staffing, combined with contract maintenance operations, is sufficient for management of the system. General comparisons were made regarding the Town s staffing levels and assigned budgets as compared to nine Bay Area sewer collection systems. This informal survey, which was conducted by VWHA as part of an unrelated project, showed that engineering staff ranged from 0.85 to 1.5 FTE per 100 miles of pipe. Additional staff provide management and administrative support. Staffing variations are expected, because agencies have different system needs, objectives, and management philosophies. Small agencies, including the Town, should plan for a higher overall cost per mile than larger agencies. When adjusted to reflect the Town's 53 miles of pipe, the Town should plan to allocate at least 0.8 FTE of engineering labor for the management of sewer system activities, in addition to supplemental management and administrative support. Based on the description of responsibilities that are assigned to the current Senior Engineer, it appears that the current engineering staffing level is low. Additional staff support, potentially using contract assistance, will likely be required if development activities or administrative responsibilities currently handled by the Senior Engineer increase, or to cover vacations or absences. Similarly, the survey indicated that maintenance staffing should range from 3 to 5 FTE per 100 miles of sewer system. On average, the fully loaded cost for sewer maintenance staff can range from $100 to $125/hour, which includes an allowance for sewer maintenance vehicles and equipment. Using these general numbers, anticipated annual cost of service is within the range of $700,000 to $1.2 million per hundred miles of pipe. When this unit cost is adjusted to reflect the Town s 53 miles of sewer pipelines, the anticipated annual budget could on the higher end of $400,000 to $650,000. Using this guideline, the Town s sewer maintenance budget would be high for the system size if the Town had a system that did not have elevated maintenance needs. However, additional costs should be anticipated in the near-term due to the need for aggressive root control, to complete system-wide CCTV inspection, and to update the Town s planning documents. In addition, as CCTV inspection results become known, the Town should plan to fund a temporary increase in pipeline spot and other repairs.

23 Page 23 A general rule of thumb for capital replacement budgeting is to assume a 15- to 30-year service life for mechanical components, and a 70- to 100-year service life for pipelines. Older systems that have had deferred maintenance may require a higher rate of replacement for a short period of time, in order to bring the overall system into this regular asset replacement cycle. The Regional Board recently announced its intention to review sewer system capital improvement programs, and to expect a two percent annual replacement rate for agencies with aging sewer systems. When this approach is applied to the Town s linear assets, the Town should plan to replace two percent of the system pipelines annually in the near-term, transitioning eventually to a one-percent replacement rate or 100-year asset replacement cycle. A very rough estimate of anticipated cost for this program, which assumes an average cost of $200 per lineal foot of rehabilitated pipe and appurtenances, is $1,000,000 per year for the near-term program, transitioning to a $500,000 annual replacement budget. Using this guideline, the Town s FY capital replacement budget should be increased to over $1,000,000 per year for pipeline improvements, with additional budget assigned for pump station improvements, flow monitoring, the Master Plan Update, and rate studies. The costs provided are approximate, and will vary from year to year, depending on the actual projects that are selected for implementation. 4.0 FINDINGS AND RECOMMENDATIONS Table 4-1 on the following page provides a summary of the findings and recommendations that are discussed in this TM. A similar Table, found in the Executive Summary, provides estimated costs for the described activities.

24 Page 24 Table 4-1. Summary of Recommendations Topic Recommended Actions Sewer System Management Plan Capacity Assurance Correct the SSMP format as required by the SWRCB Incorporate changes to the SSMP that were discussed by VWHA and Town staff. In addition, update the document to reflect other recommendations and actions that result from this assessment. Update the bi-annual audit. Although not required, it is recommended that the Town consider obtaining an external audit in lieu of a self-audit. Re-adopt the updated SSMP as soon as practical Continue to defer the implementation of capacity recommendations presented in the 2004 Master Plan, due to the insufficiency of data and tools that were available for the underlying hydraulic analysis Update the hydraulic model and Master Plan using information from the updated GIS, updated buildout projections, comprehensive and reliable flow data, and a fully dynamic, computerized hydraulic modeling tool Establish a contracting mechanism to enable collection of flow data during the wet weather season Consider how and where parcels that are currently on septic systems should connect to the existing system. Formalize and enforce this strategy as a standard requirement of each conversion. System Data Develop a temporary workaround plan for addressing map inconsistencies in the field Conduct a review of the Lucity CMMS in 6 months, to confirm that data is collected and stored in a manner that is acceptable and useful to Town staff Develop a plan to collect and correct GIS-related issues as they are identified Develop a strategy for collecting manhole elevation data, depths to pipe invert, and to confirm inlet and outlet pipe diameters where visible during maintenance operations, and to add this information to the GIS database System Maintenance Clean all pipes that have not been cleaned in the past year Formalize an initial hot spot cleaning program, and develop a Standard Operating Procedure for adding and removing future lines from this program Conduct a peer review of West Bay cleaning results using post-cleaning CCTV data Use collected CCTV inspection data to identify pipes that would benefit from a second round of chemical root control within the next two years Develop a system-wide CCTV approach and plan that obtains inspection data for the entire system as quickly as practical Continue implementation of the pump station maintenance program Rehabilitation and Review future West Bay CCTV inspection results and utilize these results, and associated Replacement recommendations, to develop a prioritized near-term rehabilitation strategy that reduces risk through consideration of likelihood and consequence of failure Cost of Service Review capital and operating budgets and update as required to address future changes to the Town s sewer system management and maintenance approach.

25 Legend ( $ $ $ Sewer Manholes Town of Los Altos Hills Pipes O'Keefe Court LS City of Palo Alto Pipes Purissima PS Other PS City of Los Altos Pipes Private and Future Pipes Figure 1-1 Town of Los Altos Hills Sewer System Assessment System Map Including Pipeline Ownership Los Altos Hills Town Limits ± 1 Miles

26 Legend $ $ $ Purissima PS Branch 2 Branch 6 Other PS Branch 4 Los Altos Hills Town Limits O'Keefe Court LS Branch 1 Branch 3 Branch 5 Branch 7 Figure 1-2 Town of Los Altos Hills Sewer System Assessment System Map Showing Drainage Basins or "Branches" ± 1 Miles

27 Legend Sewershed!.!.!.!.!.!.!.!.!.!. Palo Alto 1 Palo Alto 2 Palo Alto 3 Upper Palo Alto 3 Lower Los Altos 1 Los Altos 1A Los Altos 2 Upper Los Altos 2 Lower Los Altos 3 Los Altos 4 Service Area Boundary Pipes Owned by Others Town of Los Altos Hills Unmetered Pipes Ü Miles Figure 2-1 Town of Los Altos Hills Sewer System Assessment Proposed Flowmeter Locations

28 FIGURE 3-1 EXAMPLE MAP GRID N/A Grid N/A Grid B Grid C Grid A C Town of Los Altos Hills Sewer Collection System Map Updated 10/31/2014 Note MH IDs Labeled with "C" Within Grid "B" Legend ± ± 500 Feet ) " CLEANOUT G JUNCTION (! MANHOLE S " PUMP STATION Sewer Pipelines Map Grid Town Boundary Grid E