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�� Page 5 <br /> City of Decatur,IL <br /> CMOM and Consent Order Compliance Program <br /> Task 4: SEWER COLLECTION SYSTEM ALTERNATIVES ANALYSIS(SCSAA) <br /> The purpose of the SCSAA is to develop and implement alternatives to eliminate excessive I/I in <br /> specific areas with the collection system, or Target Areas (as identified in the SSMP), causing wet <br /> weather related SSOs, CSOs, and Property Backups. This task will focus only on the previously <br /> identified and reported target areas as shown in Attachment D of the draft Order. In addition the <br /> sewer backup areas will be identified outside the Attachment D areas. An assessment of the <br /> existing GIS and sewer modeling program will be done to determine if the sewer backup areas <br /> can be modeled to determine a solution to the backup issues. A TM will be prepared to <br /> document the backup areas and modeling capabilities. Any additional model development will be <br /> reviewed with the City prior to the work being done. <br /> Development of the SCSAA shall consider procedures outlined in the 1991 EPA "Handbook <br /> Sewer System Infrastructure Analysis and Rehabilitation"and in the"Existing Sewer Evaluation & <br /> Rehabilitation," Water Environmental Federation (WEF) Manual of Practice FD-6, ASCE Manual <br /> and Report on Engineering Practice No. 62. <br /> See Order, paragraphs 46 to 49. <br /> 4.1. Review existing information, reports, and studies, and relevance to current conditions <br /> 4.1.1. Previous engineering studies <br /> 4.1.2. As-built Sanitary, Combined, and Storm Sewer collection system maps <br /> 4.1.3. Previous Sewer System Operations and Maintenance data (i.e. sewer inspection <br /> data) <br /> 4.1.4. Existing city planning documents <br /> 4.1.5. Sewer System Monitoring data (i.e. ex. previous flow monitoring data or lift station <br /> flow records) <br /> 4.1.6. Rainfall data <br /> 4.1.7. Geotechnical and soil data <br /> 4.1.8. Groundwater data <br /> 4.1.9. Previous collecfion system performance data (i.e. SSOs, CSOs and Property <br /> Backups) <br /> 4.1.10.Stormwater Master Plan— Phase I, 2009 Update Pre-Final Report (June 2009) <br /> 4.2. Conduct an assessment of the Target Areas for development of an Alternatives Analysis <br /> (See 4.4 below). <br /> 4.2.1. Consider location of previous SSOs, CSOs and Property Backups (Excessive I/I) in <br /> a specific area <br /> 4.2.1.1. Evaluate alternatives identified in previous reports and studies <br /> 4.2.1.2. Evaluate how existing data was used to develop the alternatives and target <br /> areas. <br /> 4.2.1.3. Assess each targeted area and the reason behind why the area is being <br /> targeted. <br /> 4.2.2. Rank Target Areas in terms of <br /> 4.2.2.1. Highest contribution of I/I <br /> 4.2.2.2. Least amount of conveyance capacity <br /> 4.2.2.3. Combination of both <br /> 4.2.3. Identify hydraulic deficiencies within the Separate Sanitary Sewer Collection System <br /> and Combined Sanitary Sewer Collection System through development of a basic <br /> hydraulic model of the collection system for use in the identification and analysis of <br /> alternatives. The hydraulic model will be developed using InfoWorks (current <br /> version). The model will incorporate the following information where readily available <br /> from existing sources: <br /> 4.2.3.1. Existing SDD hydraulic model <br /> 4.2.3.2. Flow data—either from previous sources or currently ongoing <br />