Sewer Modeling and Preliminary Design Evaluations Guidance Document and Case Study Report to Address Nitrogen TMDLs at Popponesset Bay and Mashpee, MA.

 

 Stearns & Wheler-GHD Inc., November 2005

 

This document has been prepared to assist communities in Cape Cod, coastal Massachusetts, and other coastal communities with similar wastewater management concerns to identify and evaluate wastewater collection systems (sewers) that are cost effective and protective of the environment.  The procedures presented in this document can be an integral part of wastewater management planning efforts on Cape Cod and elsewhere, and are typically used as the basis for preliminary and detailed design.

The planning and preliminary design of sewers represents a large challenge for many communities on Cape Cod, especially those with no current wastewater collection systems.

Part 1 of this document describes the various sewer technologies available, including gravity sewers and pumping stations, low-pressure sewers, septic tank effluent systems, and vacuum sewers.  Each technology is described and includes the major advantages and disadvantages.  Additionally, Part 1 describes the major considerations of developing a sewer model and provides a step-by-step procedure for evaluating and modeling sewer systems.

Part 2 of the document provides a case study of the application of sewer models in the Popponesset Watershed of Mashpee, MA.  This watershed has been documented as contributing excessive non-point source nitrogen to Popponesset Bay and exceeding the nitrogen total maximum daily load (TMDL) of the Bay as determined by the Massachusetts Department of Environmental Protection.  Sewering and advanced nitrogen treatment of the wastewater is one of the methods that the towns in this watershed propose to use to meet the nitrogen TMDL.

The full report is divided into several smaller files for easier download.

1) Cover, Executive Summary, Table of Contents

2) Part 1  Sewer System Technologies and Sewer Model Setup

3) Part 2 Popponesset Bay Watershed System Evaluation Case Study- Intro and Case Study Location

4) Part 2 Popponesset Bay Watershed System Evaluation Case Study- Sewer System Evaluation

5) Appendix A - Illustration of Individual Sewersheds and Combined Gravity/Low Pressure Sewer Layout

 

 

Please contact Nate Weeks at Stearns & Wheler-GHD Inc. (508-362-5680 ext 11, or nathan.weeks@ghd.com) if you have questions or comments.

Key Words:  sewer; model; GHD; Stearns & Wheler; Cape Cod; Mashpee; Popponesset; vacuum sewer; sewerCAD