TOWN OF LINCOLN, RHODE ISLAND FINAL WASTEWATER FACILITIES PLAN NOVEMBER 2006 Prepared by: C&E Engineering Partners, Inc. 342 Park Avenue Woonsocket, Rhode Island 02895 C&E Project No. J0506 TABLE OF CONTENTS Executive Summary..................................................................................................... i Chapter 1 – Introduction ............................................................................................ 1-1 1.1 Purpose and Scope .................................................................................................. 1-1 1.2 Planning Area.......................................................................................................... 1-3 Chapter 2 – Discharge Limitations ............................................................................ 2-1 Chapter 3 – Current Conditions ................................................................................ 3-1 3.1 General ................................................................................................................... 3-1 3.2 Planning Area.......................................................................................................... 3-1 3.2.1 Geophysical..................................................................................................... 3-1 3.2.2 Demographic and Land Use Data................................................................... 3-7 3.2.3 Surface Water.................................................................................................. 3-9 3.2.4 Groundwater ...................................................................................................3-12 3.2.5 Water Use........................................................................................................3-14 3.2.6 Environmental Conditions ..............................................................................3-16 3.2.6.1 Air Quality.................................................................................................3-16 3.2.6.2 Noise Levels..............................................................................................3-17 3.2.6.3 Wetlands....................................................................................................3-17 3.2.6.4 Floodplains ................................................................................................3-19 3.2.6.5 Historical and Archaeological Significance ..............................................3-19 3.2.6.6 Energy Use ................................................................................................3-20 3.2.6.7 Related Projects.........................................................................................3-21 3.2.6.8 Rare and Endangered Species ...................................................................3-23 3.3 Wastewater Systems ...............................................................................................3-25 3.3.1 Collection System ...........................................................................................3-26 3.3.2 Pump Stations .................................................................................................3-29 3.3.2.1 Submersible Grinder Pump Stations ........................................................3-29 3.3.2.2 Wet Well / Dry Well Pump Stations .........................................................3-34 3.3.2.3 Screw Pump Station .................................................................................3-38 3.3.3 ISDS ..............................................................................................................3-41 3.3.4 Wastewater Flows...........................................................................................3-44 3.3.5 Infiltration / Inflow Preliminary Assessment..................................................3-47 TABLE OF CONTENTS (CONT.) Chapter 4 – Future/Planning Conditions .................................................................. 4-1 4.1 Demographic Projections........................................................................................ 4-1 4.2 Land Use Projections .............................................................................................. 4-2 4.3 Economic Projections............................................................................................. 4-3 4.4 Wastewater Projections........................................................................................... 4-4 4.4.1 Wastewater...................................................................................................... 4-4 4.4.2 Septage .......................................................................................................... 4-6 Chapter 5 – Wastewater Management Alternatives ................................................ 5-1 5.1 Operation of Existing Facilities .............................................................................. 5-1 5.2 Regional Solutions .................................................................................................. 5-3 5.3 Unsewered Areas .................................................................................................... 5-4 5.3.1 Individual Sewage Disposal System............................................................... 5-5 5.3.1.1 ISDS and Septage Management ................................................................ 5-6 5.4 Sewer Extensions ....................................................................................................5-12 5.4.1 Summary of Sewer Extension Alternatives.......................................................5-14 Chapter 6 – Recommended Plan and Evaluation of Alternatives........................... 6-1 6.1 Recommended Plan................................................................................................. 6-1 6.1.1 Collection System ........................................................................................... 6-1 6.1.2 Pump Stations ................................................................................................ 6-3 6.1.2.1 Submersible Grinder Pump Stations ......................................................... 6-3 6.1.2.2 Wet Well Dry Well Pump Stations ........................................................... 6-4 6.1.2.3 Screw Pump Station ................................................................................. 6-6 6.1.3 ISDS ............................................................................................................... 6-6 6.2 Evaluation of Alternatives ...................................................................................... 6-7 6.2.1 Collection System ........................................................................................... 6-8 6.2.2 Pump Stations ................................................................................................6-12 6.2.2.1 Gravity Sewer Pump Station Replacement ..............................................6-13 6.2.3 ISDS ..............................................................................................................6-14 TABLE OF CONTENTS (CONT.) 6.3 Environmental Impacts of the Recommended Plan................................................6-16 6.3.1 Future Environment without the Project.........................................................6-16 6.3.2 Water Quality and Aquatic Life......................................................................6-17 6.3.3 Wetlands and Floodplains...............................................................................6-17 6.3.4 Traffic and Noise ...........................................................................................6-18 6.3.5 Air Quality ......................................................................................................6-20 6.3.6 Hydrology and Drainage.................................................................................6-20 6.3.7 Economic Impact ............................................................................................6-21 6.3.8 Cultural, Historical and Archeological Impacts..............................................6-22 6.3.9 Wild and Scenic Rivers...................................................................................6-22 6.3.10 Secondary Impacts..........................................................................................6-22 6.3.11 Mitigation Measures for the Proposed Alternative.........................................6-22 6.4 Summary of Costs ..................................................................................................6-24 Chapter 7 – Recommended Plan Implementation.................................................... 7-1 7.1 Institutional Responsibilities................................................................................... 7-1 7.2 Implementation Schedule........................................................................................ 7-3 7.3 Operation and Maintenance .................................................................................... 7-5 7.3.1 Staffing Plan.................................................................................................... 7-6 7.4 Financial Impact Analysis....................................................................................... 7-6 Chapter 8 – Public Participation................................................................................ 8-1 8.1 General ................................................................................................................... 8-1