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<br />hour basis. Th~olume of additional flow due to the st~ events (III) shall be computed <br />and compared to the volume of rainfall during the event. The ratio of III to rainfall volume <br />shall be computed for each of up to five storm events and for each monitored area. In <br />addition, peak flow ratios shall be computed. These findings shall be used to assess the <br />absolute magnitude of rainfall-dependent III and to rank the areas accordingly. In addition <br />to the rainfall-dependent III analysis, an analysis of groundwater infiltration sliall also be <br />conducted. This analysis shall quantify the amount of groundwater infiltration present in <br />each monitored area, based on changes in base flow levels after storms and on the <br />magnitude of minimum flows occurring at night relative to average daily flows. These <br />findings shall be used to assess the absolute magnitude of groundwater infiltration and to <br />rank the areas accordingly. <br /> <br />4.4 Present the fmdings in a technical memorandum, which shall include recommendations on <br />further physical investigations (e.g., smoke testing, flow isolations, additional monitoring, <br />additional television inspection, etc.). Guidelines established by OCSD shall be considered <br />in this evaluation. The cost-effectiveness of III reduction measures determined in other <br />studies shall be considered as well. <br /> <br />5. Perform Additional Phvsical Investigations <br /> <br />5.1 Perform additional sewer television inspections as recommended based on the findings from <br />the flow analysis and considering the City's existing sewer inspection tapes and logs. <br />Additional sewer videotaping shall be recommended in selected areas to determine <br />representative structural conditions for sewers of similar age, and to identify potential <br />sources of III (as well as maintenance needs). Other inspections shall be reserved for later in <br />the study when sewers with inadequate capacity have been identified for replacement or <br />relief. A total of25,000 feet of sewer shall be cleaned and televised. The videos shall be <br />provided on VHS tape and also on CD-ROM. The observations shall be input to a database, <br />and reports and maps of the findings shall be prepared, including the observations and <br />structural condition scores for each televised pipe. <br /> <br />5.2 Perform smoke testing as an amendment to this current scope of work only if previous <br />analyses indicate that it shall be productive. If smoke testing is performed, the fmdings shall <br />be documented in a database and with digital photographs of all defects. A detailed scope of <br />work and budget for this task shall be prepared upon authorization by the City. <br /> <br />5.3 Perform flow isolations as an amendment to this scope of work only if previous analysis <br />indicate that it shall be productive. If flow isolation is performed, the findings shall be <br />documented in a report which ranks all monitored areas in terms of gpd/in-mile of tributary <br />sewer. A detailed scope of work and budget for this task shall be prepared upon authorization <br />by the City. <br /> <br />6. Develop and Calibrate a Hvdraulic Model <br /> <br />6.1 Develop a dynamic hydraulic model of the previously-designated pipes in the City's sewer <br />system (up to 1800 pipes). hnport the graphical and tabular sewer data and land use data <br />prepared in previous tasks into the modeling software (HydroWorks). Also import the data <br /> <br />CS 387 FORM: C:\OOCU!\otE~l\c1ceshaw\LOCALS-I\Temp\Agrcement Pack3gc for city Anomt:)'_,doc <br />