Fort Walton Beach Council agenda — 04-12-11 regular — reading text

technical memorandum summarizing the results and providing a recommendation for which areas / line segments need additional inspection. CH2M HILL' s PM will meet with the City to review the TM and confirm the Phase II Field Inspection Plan. PNSITASK ORDER 2 - SSES PILOT STUDY FINAL. DOCX Smoke Testing The smoke testing program will force non -toxic smoke into the sewer pipes with a high - volume mechanical blower and observe the areas from which the smoke appears. While the blower is running, CH2M HILL will travel throughout the area documenting, photographing, and getting physical measurements of the observed defects in a line segment -by- segment process. The white smoke should appear from sources of private - sector inflow (i.e. downspouts and area or yard drains on the roofs of buildings) and public - sector inflow (i.e. defects in the collection system such as directly and indirectly connected storm sewer inlets and vented manhole covers that are subject to ponding). Public notices will be prepared by CH2M HILL to inform the area residents of the smoke testing activities. Individual notices will be delivered by the City to businesses and institutions. Residential notification will be performed by the City through direct mailings and media releases. In addition, additional notifications such as newspaper notices and use of the City' s website to keep residents informed of the smoke testing activities are recommended. Observed sources of 1/ I for both public- and private- sectors will be recorded on field inspection forms and then compiled in an Access database which could then be migrated by the City into the City' s Geographic Information System (GIS) once it is developed. This task order is based on 35,000 linear feet of sewer lines being tested. Manhole Inspection with Visual Pipe Lamping Visible manholes within the selected basins will be inspected from the street surface. Non - visible manholes will not noted on the field forms and provided to the City for further investigation and location. Each manhole will be inspected to document the condition of the manhole casting, barrel sections, base, and pipe connections. Manhole center invert elevations will also be measured in each manhole. For manholes with multiple pipes entering or where there is an apparent elevation difference between incoming and outgoing pipes, a measurement from the rim to the pipe invert will be made without entering the manhole unless it is felt that such measurement would be inaccurate due to angling of the level rod or other reason. Selected internal measurements will be performed if necessary to obtain an accurate invert elevation or pipe diameter. A digital photograph of the lid and interior of the structure will be taken. In addition, a pole- mounted camera/ recorder, similar to a QuickView® manufactured by Envirosight®, will be utilized to take pictures and record views from the manhole of the connecting pipes. All observations of manhole condition and leakage will be recorded on field inspection forms and then compiled in an Access database which could then be migrated by the City into the City' s Geographic Information System GIS) once it is developed. This task order is based on 150 manholes being inspected. Flow Monitoring Flow monitors will be installed and monitored at key locations identified by CH2M HILL and City staff. Flow monitoring duration will depend on rain events, but is anticipated to be conducted over a 60 -day period to establish sufficient data. Monitoring period will need to capture at least six ( 6) rain events with at least 6 -inch of total rainfall and at least one rain event approaching a one -year typical event. Weekly field checks and data downloads will be performed during the first month of installation to verify meter operation. Following the PNSfTASK ORDER 2 - SSES PILOT STUDY FINAL. DOCX first month, field meter checks and data downloads will be less frequent but will be at least monthly, prior to significant rainfall events, and following rainfall events that exceed 1 inch of precipitation. More frequent checking will be performed immediately after installation to verify proper meter operation. A formal log of each data download will be recorded. The manhole number (meter location), date, and the time of manual depth verification will be indicated on the log. Photographs of each flow meter installation will be taken including topside and internal showing meter locations. During flow monitoring, rain data will be obtained from existing rain gauges maintained by the City. City rain gauges will be checked by the City staff at the beginning of the 3 N monitoring period and weekly after every rain event thereafter. r 0 This task order is based on flow meters being installed at three (3) different locations for 60- a day duration. W co 2 Phase II Field Inspection Components Based on the information gathered during Phase I inspections, additional inspections under L Phase II will be conducted on line segments where insufficient information was obtained during Phase I inspections, or additional information will need to be obtained based on p Y Phase I observations to further evaluate the extent of the I/ I identified in Phase 1. A list of specific inspections and tests that will be included under Phase II are as follows. 00 Limited CCTV with Pre -Cleaning N Closed circuit televising (CCTV) will be conducted on line segments identified in the Phase I Field Inspection Summary TM to identify pipe defects that could contribute to I/ I in the system. The CCTV inspections shall follow the NASSCO Pipeline Assessment Condition u. Program (PACP). During CCTV, the crew operator will capture a full inspection of each pipeline using a color, pan- and -tilt CCTV camera. Inspection protocols will follow standards set forth in the current version NASSCO specifications. Each defect associated c with I / I, structural, and O &M deficiencies will be logged during the actual inspection. a Voice -over will be included where additional and detailed explanation is needed. Data will W be entered into the WinCan®software platform or equivalent. At the completion of the W televising work, written reports and digital versatile disk (DVD) data will be prepared to N document the results of the televising work. L 0 This task order is based on 9, 000 linear feet of sewer lines being inspected by CCTV. Y NJ Dye Testing In some cases, dye testing may need to be conducted concurrently with CCTV inspections and during wet weather events. Line segments with suspected I/ I requiring dyed water testing will be identified on the basis of manhole /visual pipe (lamping) inspection and smoke test results. Prior to initiating dyed water testing, a list of line segments Q recommended for dyed water testing will be provided to the City for review and approval. The line segments on the list will be annotated as to the priority and reason for recommendation. The dyed water will be introduced into the line by localized flooding of storm sewers or drainage ditches. In addition, suspect I/ I connections from private property may also be subjected to dyed water testing. Sufficient time will be allowed for the source to activate at which time the CCTV inspection equipment will be introduced into the PNS/ TASK ORDER 2 - SSES PILOT STUDY FINAL.DOCX line segment. Flow quantification by "eyeball" estimates will be performed on high rate I/ I sources. This task order is based on 75 dye test being performed. Private Lateral Investigation Lateral CCTV inspections will be performed on line segments identified in the Phase I Field Inspection Summary TM and after the City obtains approval from the property owner. Lateral CCTV will be conducted from the main sewer using a small diameter closed circuit camera and recorded on a DVD or flash drive. As an alternative, lateral CCTV may be performed from the house to the main with permission from the homeowner when an existing cleanout is not available for the CCTV camera to be introduced into the lateral. This task order is based on 115 private lateral investigations being conducted. Deliverables Sample Public Notices Wording (for smoke testing) Phase I Field Inspection Summary TM - Draft (electronic only) Phase I Field Inspection Summary - Final (electronic only) Phase II Field Inspection Summary TM - Draft (electronic only) Phase II Field Inspection Summary TM - Final (electronic only) Task 3 — Model Development, III Data Review, and System Analysis 3. 1 Model Construction and Calibration CH2M HILL will develop a hydrologic/ hydraulic model for the study area using MWH Soft' s InfoSWMM® software. The model will include pipes 8 inches and larger with some select 6 inch diameter pipes as necessary to develop the model. The inventory for the modeled system will be collected from the City' s maps, GIS data, and record drawings provided by the City. Missing data and other data gaps necessary for modeling will be estimated based on assumptions, interpolation, staff' s knowledge or additional field work provided by the City. 3. 2 Field Data Analysis M CH2M HILL will review and catalog each field data form and note any missing data. Smoke test photos will be reviewed to ensure that background reference points appear in E the photo. Manhole, visual pipe, and smoke test forms will be reviewed to ensure that they 0 correlate with the City's maps, and field data will be checked to ensure correlation with the hydraulic network. Q Data from the field inspection forms will be entered into an electronic database developed and maintained by CH2M HILL for uniformity of analysis and incorporation into the hydraulic model. Data will be entered concurrently with the field inspections performed in Task 2 to minimize errors, and to address and correct the identified errors in a timely manner after the inspection is performed. Field inspection data will be compiled and analyzed. The defects identified (actual and suspect) will be flow -quantified for each I/ I PNSITASK ORDER 2 . SSES PILOT STUDY FINAL. DOCX source using observed or estimated I/ I rates as a basis. The defects will be prioritized based on the ratio of repair cost to estimated I/ I removed ($ / gallon per day) based on the City' s agreement with Okaloosa County. Individual defects will be identified and grouped by manhole, sewer line, and private sector. An analysis of the total flow identified versus