Final Draft - Wastewater Collection System Capacity Analysis Apprendix A April, 1999

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Final Report City of Paris, Texas Wastewater Collection System Capacity Analysis system investment program was identified. As shown above, rehabilitation of the Top 5 ranked basins combined with the associated replacements results in a restoration of hydraulic capacity for the predicted design event. It is recommended that the City commence with the rehabilitation program described in the following sections. Further the City should consider the use of post-rehabilitation flow monitoring to determine the overall effectiveness of the program and to update and calibrate the model. The City should also pursue an aggressive maintenance program to minimize local conditions that are not revealed by the model. Tools and Techniques This section describes the overall accumulation of data for the model as well as the techniques used to analyze the data. This section is followed by the results section and the basin summaries. Sources of Data In the modeling of collection systems, the primary representations are those for flow and for the piping system. Each of these aspects of the model comes from several sources. The following paragraphs describe how the information was accumulated and integrated to provide an overall model of the collection system. Any assumptions that were made are also described in this section. Flow Metering A temporary flow monitoring program was conducted for the City by ADS Environmental Services in 1996. In this portion of the program, flow measuring devices were installed throughout the system. These devices measured the flow in the sewers throughout the monitoring period. The monitoring period included both dry and wet weather conditions. This allows the system to be evaluated for system responses to stressed conditions created by rainfall. Rain gauges were also installed throughout the system to accurately measure the rainfall that fell in different areas of the system. This data was used to determine the operations of the system in both normal dry weather conditions as well as in stressed, wet weather conditions. These flows are subsequently used as the basis for determining the capacity of the system. Analysis While the data sets created from the flow monitoring process are useful, additional quantitative analyses of the data provided more valuable insights into how the system is currently operating (1996). A baseline of performance was established by defining the Average Dry Day flow patterns for each meter location. Once defined, this is used as the basis to quantify what occurs in the system during a"stressed" state. This section discusses the components of flow and the design storm projections. 5