Laserfiche WebLink
<br />'. <br /> <br />"'" <br /> <br />"-' <br /> <br />City of Santa Ana Sewer Master Plan - Amendment <br />Scope of Work for Wet Weather Flow Monitoring and III Study <br /> <br />Background <br /> <br />Due to a lack of rainfall in 2002, portions of some tasks in the original Master Plan scope of <br />work could not be completed according to the original project schedule and were deferred. <br />These tasks involved the use of wet weather flow data to perform an VI Study, and wet weather <br />peak flow capacity analysis. The deferred work was previously identified and the affected task <br />budgets were reduced accordingly. The deferred budget was set aside in a task called "Future <br />VI Study". <br /> <br />A second attempt to obtain the required wet weather flow data will be made in early 2003. The <br />scope of work for this amendment covers additional flow monitoring, as well as the associated <br />analysis and project management work. In cases where these work items were included in the <br />original scope of work and deferred, reference is made to the original tasks. The cost estimates <br />for the tasks described below include all costs associated with the tasks, whether or not they <br />were included in the original scope of work. Therefore, the budget set aside in the "Future VI <br />Study" task has been subtracted from this new cost estimate to determine the net increase in <br />budget required to complete the Sewer Master Plan. <br /> <br />Task II. Perform Wet Weather Flow Monitoring and Analvsis <br /> <br />11.1 Review the flow monitoring conducted in 2002. Determine appropriate <br />locations for up to 12 temporary flow monitors to provide information for wet <br />weather model calibration and an infiltration/inflow (VI) study. Emphasis will <br />be placed on older sewers and suspected VI problem areas. Prepare a monitoring <br />plan summarizing the recommended monitoring program, including the number <br />and location of monitors, the reason for each monitor, and the procedure to be <br />used to determine when the monitors should be installed and removed. <br /> <br />11.2 Upon approval of the monitoring plan by the City, install and maintain up to 12 <br />temporary depth-velocity flow monitors for up to eight weeks. Obtain calibrated <br />NEXRAD rainfall data for the monitoring period for use in the VI analysis. <br />Provide depth, velocity, and flow in IS-minute increments in electronic form and <br />as flow hydro graph plots. <br /> <br />11.3 Analyze the flow and rainfall monitoring data to estimate rainfall-dependent VI <br />and groundwater infiltration for each of the temporary monitors and the 16 long- <br />term OCSD monitors. The analysis of the flow monitoring data shall consist of <br />comparing flows recorded during significant storm events to typical dry weather <br />flows on an hour-by-hour basis. The volume of additional flow due to the storm <br />events (VI) shall be computed and compared to the volume of rainfall during the <br />event. The ratio of VI to rainfall volume shall be computed for each of up to five <br /> <br />11/20/02 <br />