2014/03/12 Council Agenda Packet

• .2, plan for the design and permitting phase,a pre-permit meeting at the end of this study will be held with regulatory agencies to discuss the upcoming project. The preferred alternative will be presented and a brief site visit will be held. The meeting is listed in Task 1: Project Management. Deliverables: • Draft and final Pipeline Technical Memorandum and Calculations in electronic(PDF)format. Task 5—NPDES Modeling(Mixing Zone Study) The 1996 Brown&Caldwell mixing zone study(conducted using Visual Plumes)was adopted and the original model inputs were used. • A Mixing Zone Study will be completed to determine dispersion characteristics for two alternatives. The mixing study will evaluate Alternatives 2a and 2b for two flow conditions,8 million gallons per day (mgd)and 18 mgd. Existing ambient water data from the Rerating and Effluent Dilution Study(Brown& Caldwell, 1996)will be used. The Mixing Study will be submitted to the City as a technical memorandum and provide mixing study results and recommendations. The Snohomish River is tidally influenced water body. Due to near shore conditions of Alternative 2a and the tidal influence experienced by the river,the mixing study may require the use of CORMIX v8.0GT. CORMIX is able to model near shore boundary conditions and unsteady conditions created by tides. Initial communications with Ecology about modeling indicates this model may be required. This scope of work assumes that CORMIX will be used for modeling. Assumptions: • The City will provide updated Discharge Monitoring Reports from 2010 through 2013,which will be used to characterize effluent flows. Deliverables: • Draft and final mixing study technical memorandum in electronic (PDF)format. Task 6—Pre-Design Report Update The evaluation will be documented in a draft report to be entitled,"Pre-Design Evaluation Update for the City of Everett Outfall 025".The draft outline for the report is as follows: • Introduction • Updates to the Alternatives Analysis o Description of Alternatives o Geomorphology o River Hydraulics o Pipeline Evaluation o NPDES Modeling o Cost Estimates(update planning level and lifecycle costs for two alternatives) o Operation and Maintenance Recommendations o Evaluation • Conclusions and Recommendations Deliverables: • A draft report will be submitted to the City for review. Three paper copies of the draft and final report will be submitted. An electronic version(PDF)will be provided upon request. J:\Projects\E\Everett City of\WPCF Outfall 025\00-Project Management\Scope&Budget\2013 Pre-Design Update and Design Phase\Scope of Wolk-Update Study Everett Outfall 025-02-03-14.doc Page 4 of 5 22