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15.3 Pond System Operations and Control Manual <br /> Develop a Pond Operations and Control Manual (Manual) for use by the City in the operation of <br /> the stormwater improvements, including the control structures and valving. The operational <br /> narrative will briefly address maintenance items, taking into consideration the golf course aspect <br /> of maintenance needs. The narrative will be developed as an operation and maintenance manual <br /> with the follow elements: <br /> ■ Project goals. <br /> ■ Drainage area and system overview. <br /> ■ Detention system description. <br /> ■ Operational scenarios with control structure configurations. <br /> ■ Operational strategies to manage pond levels year-round to meet project goals and <br /> maintain water quality and pond aesthetics. <br /> ■ System operation and maintenance elements. <br /> ■ Appendices that will include record drawings, any agreements between Utilities and <br /> Parks, and other supporting documentation. <br /> 15.4 Hydraulic and Hydrologic Modeling <br /> To support the development of the Manual, hydraulic and hydrologic model simulations will be <br /> completed to assess the current performance and provide operational and control strategies for <br /> the pond system. Modeling will include the following elements: <br /> ■ Assess the performance and validate hydraulic model with field data collected by the <br /> City, if available. <br /> ■ Simulate typical annual inflow patterns and approximate the appropriate storage <br /> volumes and maximum pond level needed for adequate detention. Determine if <br /> seasonal pond level adjustments are appropriate and provide recommended timing <br /> and action. <br /> ■ Identify the type of rain forecast that would trigger the need to open the control valves <br /> to intentionally lower the pond level for extra (maximum) storage volume. <br /> ■ Characterize what types of rain events would cause either of the CDS units to go into <br /> "bypass mode" or otherwise create unacceptable tail-water conditions into the <br /> collection network. <br /> ■ Characterize overflow rate through the restrictor orifices and over weirs versus pond <br /> depth. <br /> All model results will be documented in the Manual with supporting information presented in the <br /> appendices, as needed. <br /> City of Everett MURRAYSMITH Legion Golf Stormwater <br /> July 2019 2 <br />