Agenda - Council - 05/27/2003 - Laserfiche WebLink

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I I I I I I I I '1 I I I I I I I I I Response: See response to Comment 4.1 above. Comment 4.3: Section 18b. Paragraph 4 ~ The revised document makes recommendations that the City contact the MCES to make a new agreement for allocated capacity. Is this the City's document? If it is I think the language should be modified so that the City is not making recommendations to the City. Response: True, this is the City's document, but clearly it consists of a series of recommendations to the City by the document preparer. The final mitigation plhn will be changed to more directly reflect actions that will be taken by the City. Comment 4.4: Section 18b. Paragraph 6 ~ The Mississippi River interceptor has a capacity of 10 MGD not 8 and the capacity of 2.8 to 3.8 MGD is controlled by down stream facilities that will need to be upgraded when the City's flow increases. Response: The paragraph has been modified as follows: The two regional interceptors serving the City have a combined peak capacity of 18.0 MGD. The Rum River MUSA District, which is served by a 30-inch diameter interceptor, has a maximum design capacity of about 8 million gallons per day (MGD). The Mississippi River MUSA District, which is served by a 30- inch diameter interceptor, has a maximum peak design capacity of about 10 ' MGD. As stated earlier, although the collection system and interceptors are designed to carry 7.87 MGD, it is assumed that only 2.8 to 3.8 MGD of average daily flow capacity is currently available in the regional system due to downstream bottlenecks. Comment 4.5: Section 18b. Paragraph 7 - ADD ~ "before upgrades will be needed in the downstream facilities." to the last sentence. Response: Changed in text as suggested. Coxmnent 4.6: Table 18.7 ~ The average daily flow for the Mississippi River District matches the flow I had figured pretty close but the peaking factor of 2.13 that they use to calculate the peak flow is less than those used in the Comprehensive Sewer Plan, which were approximately 2.3 to 2.5. Response: NAWE used the following formula to calculate peak flows from average flows less than 10 MGD (all flows in MGD): Qpeak = 3.5 - (0.333 x Qave) The method used is derived from Metcalf and Eddy, 3rd Edition, for estimating peak flows. The only difference is that for this project, the ratio of residential to commercial units when the rural areas are added is below that of a normal municipality. Because of this, the maximum peaking factor was lowered from 4 to 3.5. -151-