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Letter to EPA with Proposed Revisions (Non-Material Modification A and Non-Material Modification B) (2/4/15)Metropolitan St. Louis Sewer District 2350 MeetsbeM SI,tw t 1c3 PIo :314.7081200 wawalikcarn February 4, 2015 VIA ELECTRONIC MAIL AND U.S. MAIL Chief, Water Enforcement & Compliance Assurance Branch Water and Wetlands Protection Division U.S. Environmental Protection Agency - Region 7 Attn: Jodi Bruno 11201 Renner Blvd. Lenexa, KS 66219 Rruno.Jodi@epa.gov RE: Proposed Non -Material Modifications of CSO Control Measure Design Criteria: Proposed Non -Material Modification of CSO Control Measures: In -Sewer Storage Upstream of Lemay CSO Outfall 063 AND Lower & Middle River Des Peres Storage Tunnel Proposed Non Material Modification of CSO Control Measures: Upper River Des Peres Storage Tunnel, River Des Peres Tributaries Storage Tunnel, AND Lower & Middle River Des Peres Storage Tunnel Greetings: The Metropolitan St. Louis Sewer District ("MSD") hereby requests that the U.S. Environmental Protection Agency ("EPA") approve the proposed modifications of the Design Criteria for CSO Control Measures pursuant to Paragraphs 61 and 136 of the April 27, 2012 Consent Decree (Dkt. #159), as amended by the Court on October 10, 2013 (Dkt. #164) and by agreement on July 5, 2013 (Dkt. #161), in Cause No. 4:07-cv-01120-CEJ. The CSO Control Measures are listed in Appendix D to the Consent Decree. MSD requests the non -material modification of two (2) CSO Controi measures associated with the following CSO tributaries: In -Sewer Storage Upstream of Lemay CSO Outfall 063 and Lower & Middle River Des Peres Storage Tunnel ("Non -Material Modification A"). MSD also requests the non -material modification of three (3) CSO Control Measures associated with the following CSO storage tunnels: Upper River Des Peres Storage Tunnel, River Des Peres Tributaries Storage Tunnel, and Lower & Middle Des Peres Storage Tunnel ("Non -Material Modification B"), CHIEF, WATER ENFORCEMENT AND COMPLIANCE ASSURANCE BRANCH FEBRUARY 4, 2015 WATER AND WETLANDS PROTECTION DIVISION PAGE 2 U.S. ENVIRONMENTAL PROTECTION AGENCY - REGION 7 Non -Material Modification A Non -Material Modification A, as further described in Attachment A, will affect two (2) of the CSO Control Measures listed on Page 6 of Appendix D to the Consent Decree. The first CSO Control Measure is identified as "In -sewer Storage Upstream of Lemay CSO Outfall 063." The intent of this Control Measure was to provide 25 million gallons of storage capacity within the existing sewer system upstream of Lemay CSO Outfall 063 by means of an inflatable or moveable dam system. MSD proposes to eliminate this CSO Control Measure by increasing the storage volume of the "Lower & Middle River Des Peres Storage Tunnel" by the said 25 million gallons. MSD's proposal is based on new information developed since the entry of the Consent Decree, provides additional environmental benefits while reducing other risks, and reflects good engineering practice. This change will only affect the Design Criteria tor the "Lower & Middle River Des Peres Storage Tunnel" by increasing the storage volume (at least 25 million additional gallons) from the originally proposed 206 million gallons (i.e., a less than 20% modification of Design Criteria). Most importantly, it will not change the Performance Criteria and Critical Milestones associated with the "Lower & Middle River Des Peres Storage Tunnel" Locating all of the required CSO storage volume to the Lower & Middle River Des Peres Storage Tunnel will also provide an additional environmental benefit. Under the originally proposed CSO Control Measures, the 25 million gallons of in -sewer storage would be useable only when it rams in the upper portion of the combined sewer area (i.e., upstream of Outfall 063). By relocating the 25 million gallons of storage volume to the downstream tunnel, this volume can be utilized regardless of whether or not it is raining in the Lemay combined sewer area served by the tunnel. For the foregoing reasons, MSD respectfully requests that EPA approve Non -Material Modification A. Non -Material Modification B Non -Material Modification B, as further described in Attachment B, will affect the three (3) following CSO Control Measures listed on Pages 3, 5, and 6 of Appendix D to the Consent Decree: • Upper River Des Peres Storage Tunnel serving Lemay Outfalls 064, 066 to 096, 099 to 102, 167, 178 and 180. • River Des Peres Tributaries Storage Tunnel serving Lemay CSO Outfalls 103, 104, 105, 106, 111, 117 to 128, 130, 131, 134, 136to 140, 166 and 176. CHIEF, WATER ENFORCEMENT AND COMPLIANCE ASSURANCE BRANCH WATER AND WETLANDS PROTECTION DIVISION U.S. ENVIRONMENTAL PROTECTION AGENCY - REGION 7 FEIIRUARY 4,2015 PAGE3 • Lower & Middle River Des Peres Storage Tunnel serving Lemay CSO Outfalls 008 to 032, 036, 037, 039, 041 to 044, 048, 050, 052, 053, 054, 057, 058, 061, 063, 163, 170 to 173, and 181. MSD proposes that the Design Criteria for each of these three Control Measures be modified by deleting the "to capture flows from Lemay CSO OutfaIls..." wording, as more particularly described in Attachment B. Alternatively, MSD requests that the Consent Decree be clarified to allow MSD to use other design methods, so long as they reflect good engineering practice, in order to satisfy the specified Performance Criteria and Critical Milestones. This modification or clarification, if approved, will not change the Performance Criteria and Critical Milestones. MSD believes that this modification or clarification is necessary because the current wording could be interpreted as requiring each and every one of the named CSO Outfalls to be physically connected to the storage tunnel. This was neither the intent of the Long -Term Control Flan (LTCP) nor the Consent Decree. The parties to the LTCP and the Consent Decree recognized that MSD could utilize other acceptable design methods (i.e., other than "capture"), so long as they reflected good engineering practice and achieved the requisite Performance Criteria and Critical Milestones. Without this change, it will remain unclear as to whether MSD will have to request a modification to the Consent Decree every time that a different yet acceptable control technique is selected during the final design. In order to achieve clarity and efficiency, MSD respectfully requests that EPA approve Non - Material Modification B. Furthermore, if Non -Material Modification A and B are approved by September 1, 2015, these modifications will allow MSD to meet the Critical Milestone Dates specified in Appendix D to the Consent Decree. Demonstrating good engineering practice, the proposed modifications will also provide additional environmental benefits, reduce project risks, and allow the best engineering solutions to be applied at each CSO Outfall. For these and other reasons as outlined in the attached documents, MSD believes that the proposed modifications should be approved by EPA. Enclosed and hereby incorporated with this letter you will find the following: (1) a Proposal Document providing a detailed explanation of the proposed modifications, along with relevant information demonstrating that the proposed modifications reflect good engineering practices and will continue to achieve the required Performance Criteria (as specified in Appendix D for these CSO Control Measures); and (2) a red -lined version of relevant portions of the Consent Decree (Appendix D and Appendix E) delineating the proposed modifications to the Consent Decree. Through coordinated effort between MSD and EPA, MSD has confidence that these proposed modifications can be discussed and resolved expeditiously so that MSD can continue to meet its Critical Milestone dates. As such, MSD would like to schedule a meeting between your office and MSD technical staff to discuss any technical questions and to formulate a process for moving this matter forward. We will contact your office immediately for help coordinating a meeting_ CHIEF, WATER ENFORCEMENT AND COMPLIANCE ASSURANCE BRANCH WATER AND WETLANDS PROTECTION DIVISION U.S. ENVIRONMENTAL PROTECTION AGENCY - REGION 7 FEBRUARY 4,2015 PAGE 4 If you should have any questions with regard to this matter, please feel free to contact me. Sincerely, I 1 Susan M. Myers General Counsel cc. Brad Nevois, MSD Patricia Pride, MSD CHIEF, WATER ENFORCEMENT AND COMPLIANCE ASSURANCE BRANCH WATER AND WETLANDS PROTECTION DIVISION U.S. ENVIRONMENTAL PROTECTION AGENCY - REGION 7 FEBRUARY 4, 2015 PAGE 5 Consent ilerrL1 t..9mmusu 1iuu Lis! United States: Chief, Environmental Enforcement Section Environment and Natural Resources Division U.S. Department of Justice Box 7611 Ben Franklin Station Washington, D.C. 20044-7611 Re: DOJ No. 90-5-1-1-08111 EPA: Chief, Water Enforcement and Compliance Assurance Branch Water and Wetlands Protection Division U.S. Environmental Protection Agency, Region 7 11201 Renner Blvd. Lenexa, KS 66219 David Cozad Regional Counsel Office of Regional Counsel U.S. Environmental Protection Agency, Region 7 11201 Renner Blvd. Lenexa, KS 66219 State of Missouri: Chief Counsel Agriculture and Environment Division State of Missouri Office of Attorney General 207 W. High Street Jefferson City, MO 65102 Chief, Water Pollution Compliance and Enforcement Section Missouri Department of Natural Resources P.O. Box 176 1101 Riverside Dr. Jefferson City, MO 65101 Director, St. Louis Regional Office Missouri Department of Natural Resources 7523 South Lindbergh Blvd. St. Louis, MO 63125 Coalition: Heather B. Navarro Executive Director Missouri Coalition for the Environment 3115 S. Grand Blvd., Suite 650 St. Louis, MO 63118 Maxine I. Lipeles Elizabeth J. Hubertz Interdisciplinary Environmental Clinic Washington University School of Law One Brookings Drive Campus Box 1120 St. Louis, MO 63130 MSD: Executive Director Metropolitan St. Louis Sewer District 2350 Market Street St. Louis, MO 63103-2555 General Counsel Metropolitan St. Louis Sewer District 2350 Market Street St. Louis, MO 63103-2555 Director of Engineering Metropolitan St. Louis Sewer District 2350 Market Street St. Louis, MO 63103-2555 February 4, 2015 ATTACHMENT A Page 1 of 4 Metropolitan St. Louis Sewer District Proposed Revision of CSO Control Measures: In -Sewer Storage Upstream of Lemay CSO Outfall 063 and Lower & Middle River Des Peres Storage Tunnel The Metropolitan St. Louis Sewer District ("MSD") hereby requests that the U.S. Environmental Protection Agency ("EPA") approve the modification of the Design Criteria for two CSO Control Measures pursuant to Paragraphs 61 and 136 of the April 27, 2012 Consent Decree (Dkt. #159), as amended by the Court on October 10, 2013 (Dkt. #164) and by agreement on July 5, 2013 (Dkt. #161), in Cause No. 4:07-cv-01120-CEJ. MSD's proposed modifications are associated with CSOs tributary to the Lower & Middle River Des Peres. MSD herein demonstrates that the proposed modifications reflect good engineering practice, are based on new information developed since the entry of the Consent Decree, provide additional environmental benefits while reducing other risks, and do not change any of the Consent Decree Performance Criteria or Critical Milestones. Overview The proposed modifications affect two of the CSO Control Measures listed on Page 6 of Appendix D to the Consent Decree (see attached): • The first CSO Control Measure is "In -sewer Storage Upstream of Lemay CSO Outfall 063." The intent of this Control Measure was to provide 25 million gallons of storage capacity within the existing sewer system upstream of Lemay CSO Outfall 063 by means of an inflatable or moveable dam system. MSD proposes to eliminate this CSO Control Measure by increasing the storage volume of the "Lower & Middle River Des Peres Storage Tunnel" by the said 25 million gallons. • This change, of course, affects the Design Criteria for the "Lower & Middle River Des Peres Storage Tunnel" by increasing the storage volume from the originally proposed 206 million gallons. The increase in the tunnel storage volume represents a revision to the Design Criteria of less than 20%. MSD proposes no changes to the Performance Criteria and Critical Milestones associated with the "Lower & Middle River Des Peres Storage Tunnel." Details When the Long -Term Control Plan (LTCP) was originally prepared, it was assumed that the diameter of the CSO storage tunnel should be limited to less than 30 feet because MSD had not fully developed its understanding of deep underground conditions along the Lower and Middle River Des Peres channel where the tunnel would be located. The known presence of karstic conditions (channels, caves, etc.) in the area was thought to pose a significant challenge to large diameter tunnel construction. To keep the proposed tunnel diameter within what was believed to be an appropriate range, the LTCP moved 25 million gallons of the total 231 million gallons of CSO storage volume required to meet the Performance Criteria to the proposed in -sewer storage system. The total storage volume of 231 million gallons was thus divided between the deep tunnel (206 million gallons) and the in -sewer storage system (25 million gallons). The two February 4, 2015 ATTACHMENT A Page 2 of 4 above -noted Control Measures in Appendix D of the Consent Decree reflect this division of flow storage. The LTCP, and subsequent discussions with EPA, MDNR, and the Coalition, reviewed several potential risks associated with the in -sewer storage. These included the risk of upstream flooding and potential damage to the 29-ft horseshoe sewers and tributary sewers upstream of Outfall 063 due to surcharging of the sewers or failure of the storage dam system to operate properly, and the risk of sedimentation and odors occurring in the 29-ft horseshoe sewers beneath Forest Park as a result of the stored flow. MSD noted that these risks could be mitigated but not eliminated. A better understanding of the geology along the proposed alignment has been developed since the LTCP was written and the Consent Decree was entered. Three phases of detailed geotechnical investigations have since been conducted, including 73 deep borings with almost 16,000 feet of rock cored, and extensive geophysical investigations. It is now believed that a larger -diameter tunnel is feasible at the proposed tunnel depth. The risks of in -sewer storage can therefore be eliminated by reallocating all of the CSO storage volume required to meet Performance Criteria to the deep CSO Storage Tunnel. Locating all of the required CSO storage volume in the tunnel can also provide an additional environmental benefit. Under the originally proposed CSO Control Measures, the 25 million gallons of in -sewer storage would be useable only when it rains in the upper portion of the combined sewer area (Le., upstream of Outfall 063). By relocating the 25 million gallons of storage volume to the downstream tunnel, this volume can be utilized regardless of where it is raining in the Lemay combined sewer area served by the tunnel. The proposed changes to page 6 of Appendix D, and to page 3 of Appendix E to the Consent Decree, are noted on the following pages. February 4, 2015 ATTACHMENT A Page 3 of 4 Case: 4:07-cv-01120-CEJ Doc. #: 159.4 Filed: 04127/12 Page: 6 of 9 PagelD #: 1620 Appendix D CSO Control Measures, Design Criteria, Performance Criteria, and Critical Milestones CSO Control Measures — Lower & Middle River Des Peres CS4 Car -lira!! Mcasurie Description Svwor separation to allow elimination of CSO Outfalls Design Criteria MSU's Rules and Regulations and F^i?nrcring Design Y Performance criteria Elimination of Lemay CSO Ou1lls �' 049, l68 and 177 Critical l'illlinstnnes • Achievement of Full Operation— 01i01/2011 Elimination of Lamy CSO Outfalls 046, 049, 168 and 177 Requ 'is for sewer and Stonn for Drainage Facilities Lemay CSO Outran 062 Elimination Sewer separation to allow elimination of Lcinay CSO Outfall 062 MSD's Rules and Regulations and Engineering Design Requirements for Sanitary Sewer and Stormwaler Drainage Facilities Elimination of Laney CSO outfall 062 • Achievement of Rill Operation— 12131/2015 CSO Treatment Unit c;�.. �`; i hanccd High Rate Clarification facility II* MGD capacity providing equivalent ofprim.sry clarification, solids/floalables disposal, and disinfection When incorporated with other River Des Peres CSO controls, reduce overflows to 4 events or less in the typical yeart1j. Comply with applicable Missouri Operating Permit. • Bid Year - 2027 • Achievement of Full Operations-12/31/2030 In -sewer Storage U strearn of Lemay CSO Outfa11063 Inflatable or , 0, r system to allow flow stye in horseshoe sewers Provide 25 milIion gallons -: crustrn_ -1.` plows from r eJ,ray CSO Outfall 063 When incorporated with o , - - -. CSO controls, - „ - r ows to 4 events or less , . ., - typical YeaP V' • Achievement of Full Clpaation—12/31/2030 Lower & Middle River Des Peres Storage Tunnel CS(l OutCalls 008 to 032, 036, 037, 039, 041 to 044, 048, 050, 052, 053, 054, 057, 058, 061, 063, to 3, 163 ] 173, andL ] storage laurel agar surface facilities, speltfremAgran. 1 on' s` separation and consolida tion sewers? of 47 When incotporated with other Rive Des Peres CSO controls, reduce overflows to 4 events or leas in the typical rare!). and untreated overflow volume to the River Des Pees erf 1,412 million gallons Cram the Lower & Middle River an Peres Storage Tunnel163,170 and the River Des Peres Tributaries Storage Tunnel combined. • Bid Year — 2021 • • Achievement of F i1I Operation-12/3112030 at least 231 04., - storage volume ° r,1 r on errs m , ''' + __ 03$ier-8,�; , Modifications per Doc. #: 161 Filed: 07/05/13 Page: 3 of 9 Modifications proposed in Attachment B Modifications proposed in this request 6 February 4, 2015 ATTACHMENT A Page 4 of 4 Case: 4:07-cv 01120-CEJ Doc. #: 159-5 Filed: 04/27/12 Page: 3 of 6 PagelD #: 1626 APPENDIX E POST -CONSTRUCTION MONITORING PROGRAM Malin Creek: • O; ;.z —,�^t Local Storage Facility for Outfalls 051 and 052 Ging -as Creek: • Relocation of Outfall 059 Upper River Des Peres: • Storage tunnel to store flows from CSO outfall n to the Upper River Des Peres River Des Peres Tributaries: • Tunnel to convey/store flows to Lemay WWTF Lower and Middle River Des Peres: • Enhanced High Rate treatment unit zzat• • Removalof secondary treatment bottlenecks at WWTF • Tunnel to convey/store flows to Lemay WWTF Following Achievement of Full Operation of each CSO Control Measure listed in Appendix D, MSD shall conduct activation monitoring at all CSO outfalls addressed by that particular CSO Control Measure to determine the number of activation events at each CSO outfall, and submit the activation information in the Annual Report as set forth in Section VIII of the Consent Decree. Such activation information shall be submitted as an actual number of events. III. tress Testing of Lemav Treatment Plant MSD shall construct the CSO Control Measure in accordance with the description, design criteria, performance criteria, and critical milestones contained in Appendix D to achieve a minimum secondary treatment design capacity of 210 million gallons per day (MGD) at the Lemay Treatment Plant. The existing preliminary and primary treatment facilities have a design capacity of 340 MGD. Effluent disinfection facilities are currently being designed with a capacity of 340 MGD. MSD shall submit a stress test protocol to EPA and the State for review and for EPA's approval, with a copy to the Coalition, at least 30 days prior to Achievement of Full Operation of the upgraded wastewater treatment facilities. The protocol shall be designed to determine the maximum treatable wet -weather flow rates for each treatment step (preliminary, primary, secondary, and disinfection) at the Lemay Treatment Plant following the completion of the upgrades described above. EPA/MDNR shall review the stress test protocol pursuant to Section VII of this Consent Decree (Review and Approval Procedures). 3 Modifications per Doc. #: 164 Filed: 10/10/13 Page: 5 of 11 Modifications per Doc. #: 161 Filed: 07/05/13 Page: 3 of 9 Modifications proposed in this request February 4, 2015 ATTACHMENT B Page 1 of 5 Metropolitan St. Louis Sewer District Proposed Revision of CSO Control Measures: Upper River Des Peres Storage Tunnel, River Des Peres Tributaries Storage Tunnel, and Lower & Middle River Des Peres Storage Tunnel The Metropolitan St. Louis Sewer District ("MSD") hereby requests that the U.S. Environmental Protection Agency ("EPA") approve the modification of the Design Criteria for three CSO Control Measures pursuant to Paragraph 61 of the April 27, 2012 Consent Decree (Dkt. #159), as amended by the Court on October 10, 2013 (Dkt. #164) and by agreement on July 5, 2013 (Dkt. #161), in Cause No. 4:07-cv-01120-CEJ. MSD's proposed modifications involve the Upper River Des Peres Storage Tunnel, River Des Peres Tributaries Storage Tunnel, and the Lower & Middle River Des Peres Storage Tunnel. MSD herein demonstrates that the proposed modifications reflect good engineering practice, are based on new information developed since the entry of the Consent Decree, may provide additional environmental benefits, and will continue to achieve the Performance Criteria specified in Appendix D. Overview The proposed modifications affect three of the CSO Control Measures listed on Pages 3, 5, and 6 of Appendix D to the Consent Decree: • Upper River Des Peres Storage Tunnel serving Lemay Outfalls 064, 066 to 096, 099 to 102, 167, 178 and 180. • River Des Peres Tributaries Storage Tunnel serving Lemay CSO Outfalls 103, 104, 105, 106, 111, 117 to 128, 130, 131, 134, 136 to 140, 166 and 176. • Lower & Middle River Des Peres Storage Tunnel serving Lemay CSO Outfalls 008 to 032, 036, 037, 039, 041 to 044, 048, 050, 052, 053, 054, 057, 058, 061, 063, 163, 170 to 173, and 181. MSD proposes that the Design Criteria for each of these three Control Measures be modified and clarified by deleting the wording as indicated on the attached pages. Details At the ending of the Design Criteria description for each of the listed CSO Control Measures, the following wording was added: "...to capture flows from Lemay CSO Outfalls [followed by a listing of each CSO Outfall]." This wording was added to the Consent Decree during the very last minutes of negotiations (May 27, 2011) as the final change to the Consent Decree before execution. MSD believes that this wording could be interpreted as requiring each and every one of the named CSO Outfalls to be physically connected to the storage tunnel. MSD asserts that this was not the intent of the LTCP or Consent Decree negotiations, wherein it was recognized that other means that reflect good engineering practice or provide greater environmental benefit could be used to meet the Performance Criteria, such as partial or complete sewer separation, elimination February 4, 2015 ATTACHMENT B Page 2 of 5 of an outfall, or employing emerging technologies such as green infrastructure, if necessary to meet Performance Criteria. For example, Page 11-6 of the LTCP, discussing the Upper River Des Peres Storage Tunnel, states that "partial sewer separation may be implemented where appropriate to reduce the costs for consolidation piping, as determined during final design. Partial sewer separation may be particularly applicable to some of the outlying CSOs such as Lemay Outfalls 102 and 167." Similar language appears in the LTCP for the other tunnels indicating that control techniques could be considered and employed other than physically routing and connecting all outfalls, especially remote ones, to the tunnels. MSD is not requesting a revision of the Performance Criteria. Based on the information and analysis to date, MSD plans to meet the Performance Criteria for the CSO Control Measures for which it is requesting design modifications. However, MSD does not believe it to be productive to request a modification to the Consent Decree every time that a different yet acceptable control technique (i.e., other than capture) is selected as new information is developed during final design, as long as the Performance Criteria and Critical Milestones are achieved. Therefore, MSD requests that the indicated wording be removed from the Design Criteria, or modified so as to allow for other design methods that reflect good engineering practice to be used to meet the specified Performance Criteria. February 4, 2015 ATTACHMENT B Page 3 of 5 Case: 4:07-ev-01120-CEJ Doc. #: 159-4 Filed: 04127/12 Page; 3 of 9 PBgelD f:1617 Appendix D CSO Control Measures, Design Criteria, Performance Criteria, and Critical Milestones CSO Control Measures — Upper River Des Peres CSO CuuIrci Mcasurl? Upper River Des Peres Storage Tunnel saving Lemay (Mfalls 064, 066 to 096, 099 to 102, 167, 178 and 180 D€acriplaon Deep storage tunnel, near - surface facilities, pump station, sewer separation and consolida- tion sewers pesigrn tent€ria Provide storage volume of 30 million gallons in deep tunnel system lei-oeptarepfievre /rylam- {{��1�f jj V fl -1IX WT,�VW fv 4J �VJJ 4L V6, ivi i 10 wuu ICU Pt.rrfaerrron u CnIeria when incorporated with other River Des Peres CSO controls, reduce overflows to 4 events or less, and 94 million gallons of untreated overflow volume in the typical Yc) Upper River Des Peres CSO Controls Critical Milestones • Bid Year-- 2028 • Achievement of Full Operation— 06/30/2034 Modifications proposed in this request 3 February 4, 2015 ATTACHMENT B Page 4 of 5 Case: 4:07.cv-01120.CEJ Doc. #: 159-4 Filed: 04127/12 Page: 5 of 9 Page#D #:1019 Appendix D CSO Control Measures, Design Criteria, Performance Criteria, and Critical Milestones CSC C Measur rirel River Des rues Tributaries StorageTwmael serving Loney CSO Outtlls 103, 104, 105, 106, 111,117 to 128, 130, 131, 134, 136 to 140,166 and 176 Description Storage / conveyance tunnel, near - surface facilities, pump station, sewer separation and consolidation sewers OeErn Criteria. Conveyance tunnel with storage volume of 28 million gallons teterWrraid-146 Purim marisrf Criteria When incorporated with other RiverDes Peres CSO controls, reduce overflows to 4 events or less to River Des Peres main channel in the typical yearn Critical M ittrslormes • Bid Year - 2024 • Achievement of Full Operation- 06/30/2030 River Des Peres Tributaries CSO Controls Modifications proposed in this request 5 February 4, 2015 ATTACHMENT B Page 5 of 5 Case: 4:07-cv-01120-CEJ Doc. #: 159-4 Filed: 04/27/12 Page: 6 of 9 PagelD #: 1620 Appendix D CSO Control Measures, Design Criteria, Performance Criteria, and Critical Milestones CSO Control Measures — Lower & Middle River Des Peres CSO COlircil hrle�sier DalcriptTon Sewer to all se:Parntean elimination of CSO Outfalls DL'bFtri Crilaria MSD's Rules and Regulations and Engineering Design Requirements for Sanitary Sewer and stemmas Drains Facilities PerformanceCiilitlik Criteria Elimination of Leamay CSO Outfslls 046, 049,168 and 177 011lile+ tesne 5 • Achieveiuent of bull Operation 01/01/2011 Elimination of l emery t ionSO Oulfalls 046, 049, 168 and 177 Lemay CSO Outten 062 Elimination Sewer separation to allow elimination of lxmay CSO MSD's Rules and Regulations and Engineering Design Requirements for Sanitary Sewer and Stomtwater Drainage Facilities Elimination of%emay CSC) outfall 062 • Achievement nt of Full Operation-12/31/2015 CSO Treatment UnitRate Paced High Clarification facility 100 MCrD c itY � provi� equivalent of primtat'Y clarification, solidslflaatables disposal, and disinfection When incorporated with other River Des Peres CSO controls, reduce overflows to 4 events or less in the typical yeart'1. Comply with applicable Missouri operating Pernik. • Bid Year — 2027 • Achievement of bull Operation —12131/2030 In -sewer Storage Upstream of Lamy CSO Outfalk 063 Inflatable 0t moo system to allow flow storage in horseshoe sewers Provide 25 million gallons i within erusti c bows from LennyrIIows CSO Outfa11063 When incorporated With res CSO controls, • Achievement of Full Operation -12/31 /2030 to 4 en ass typicaalyeer0? Lower & Middle River Des Peres Storage Tunnel serving Leenay CSO Outtalls 008 to 032, 036, 037, 039, 04110 044, 048, 050 052 053, 054, OS7' 058, 061, 063, 163,170 to 173, and 181 Derp storag twmel, nearG surface iaealitier, nwrincstation,entadi8 sewer and cowhide -from tion sewers , When incorporated with other River Des POWs CSO controls, reduce overflows to 4 events or less in the typicalyear�l and eatcd overflow volume to the River Des Peres of 1,412 million gallons the Lower & Middle River De s Peres Storage Tunmel and the River Des Peres Tributaries Storage Tunnel combined • Bid Year — 2021 • Achievement of Pull Openration-12/31/2030 at least 231 i storage volume of t ion %ns to c teaniel Wean , } 1. — Modifications per Doc. #: 161 Filed: 07/05/13 Page: 3 of 9 Modifications proposed in Attachment A Modifications proposed in this request 6