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City of Arden Hills March 2008 V. Summary of Analysis Table 5 provides a summaI}' of all the data developed in the previous paragraphs. The MCES II Surcharge program is focused on the" Inflow" portion of the clear water and the highest costs for the City of Arden Hills are associated with flow in this categol}'; however, it is important to consider the infiltration portion as well since both infiltration and inflow result in treatment costs to the community. Using the data included in Table 5, the matrix in Table 6 is developed to prioritize areas for additional work. The various factors were ranked numerically from low to high with the low number reflecting the worst case, so the lowest sum will be the highest priority for additional work. Table 6. - Prtoritization Rankino Matrix Area Infiltration! in-mi PIA Ratio Inflowl in-mi Sum Prioritv Meter MaSl 1 3 2 6 2 Meter 2 3 4 6 13 S Meter 3 4 2 3 9 3 Meter M052 2 3 4 3 .- 9 Meter M054 S 2 5 12 4 Meter MOS9 5 1 1 7 1 ~ ;; ;! -+ g ;! * Note: (urrent data from Meter 1 are not sUItable for companson with other meter sheds. Meter Area M051 is the highest priority for additional work with emphasis on the area between MOS1, Meter 2 and Meter 3. However, the area served by Meter M059 had the highest Inflow Related ran kings and therefore should be considered the highest priority for the III Surcharge reduction efforts. VI. Potential III Sources to consider The flow response demonstrated in Figures 3, 5,7,9,11,13, and 15 provide one indicator ofthe type of III sources that can be anticipated in the service area. The type of sources in turn define the type of further investigative methods that should be considered in the various areas. It is impossible to completely define the sources at this stage of the process but we would anticipate that the sources \lvill be more dearly identified as the investigation effort proceeds. Figure 3 - Meter 051 Flow chart indicates a short duration quick spike in flow with the flow remaining elevated slightly for an extended period of time. This flow pattern suggests a possible mixture of some direct inflow sources, such as catch basins, area drains, low manholes, or roof drains, with some longer acting sources such as sump pump connections, direct footing drainage tile, or leaking service pipes. Figure 5 - Meter M2 flow chart shows an immediate sharp spike with the flow remaining elevated for more than a day following the peak event. This flow pattern suggests primarily longer acting type sources such as sump pumps, direct footing drain tiles, or leaking sewer service pipes. Figure 7 - Meter M3 flow chart shows an immediate sharp spike with vel}' little long term flow impacts. This pattern suggests some direct inflow sources, such as catch basins, area drains, low manholes, or roof drains, with possibly a small number of longer acting sources such as some sump pump connections, direct footing drainage tile, or leaking service pipes. Figure 9 - Meter 052 flow chart indicates a short duration quick spike in flow with the flow remaining elevated slightly for an extended period of time. This flow pattern suggests a possible mixture of some direct inflow sources, such as catch basins, area drains, low manholes, or roof drains, with some longer acting sources such as sump pump connections, direct footing drainage tile, or leaking service pipes. Page 8 of 12