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Exhibit "A" <br />Scope of Services <br />For <br />City of Casselberry Department of Public Works <br />UNIDIRECTIONAL FLUSHING PROGRAM DESIGN <br />June 30, 2010 <br />Background <br />The City of Casselberry Public Works Department (City) is considering a unidirectional flushing <br />(UDF) program to improve water quality and maintain customer satisfaction throughout its <br />potable water distribution system. In order to deliver the safe potable water to the customers, the <br />City maintains a minimum disinfectant concentration in the distribution system. Deposits in the <br />distribution system exert a significant chlorine demand that adversely affects disinfectant <br />concentrations. UDF is a proven, systematic approach to remove pipe deposits and improve <br />distribution system quality. UDF can increase disinfectant concentrations with the benefit of not <br />increasing disinfectant by-products (DBPs) that would result from boosting chlorine residuals in <br />the distribution. Utilities that have performed UDF have experienced: <br />• lower turbidity and color water, <br />• higher chlorine residuals, <br />• increased hydraulic capacity, <br />• reduced flushing volumes, and <br />• significantly lower customer complaints. <br />UDF involves a system -wide set of design sequences to open and close valves and hydrants tc <br />clean the distribution system from the source outward. Normal flushing practices typically do <br />not achieve the velocity required remove pipe deposits: UDF design uses hydraulic modeling tc <br />achieve the unidirectional flow patterns to achieve high velocities in the target pipe(s) to properly <br />scour and remove deposits from the distribution system. The City has a potable water <br />distribution hydraulic model (Model) that was updated and calibrated by Reiss Engineering, Inc. <br />(REI) in 2010. This Model is a very effective tool that can be utilized for designing a UDF <br />program. <br />Scope <br />The intent of this scope is to design a UDF program focusing on an efficient and effective <br />flushing regime to clean the distribution system piping and improve water quality. The task4, <br />included in this UDF Program Design are: <br />Task 1 — UDF Pre -Design <br />Task 2 — UDF Program Design <br />Task 3 — Field Journal Development <br />PLANNING • DESIGN • CONSTRUCTION <br />