Sewer Project: Upper North Oconee (UNO) Interceptor, Phase 2B

Project Details

Name:  Upper North Oconee Interceptor Phase 2B

Type:  Sewer

Notice to Proceed:  February 2020

Project Status:  77% complete

Expected Completion Date:  original date of September 29, 2021, but due to unusually wet weather, COVID-19, and tunneling equipment availability, construction was delayed, and the new expected completion date is January 2022  

Area for Improvements:  Along the Greenway between College Avenue and Sandy Creek Nature Center

Cost:  $10,722,222 - construction contract award approved by Mayor & Commission on November 15, 2019

Project Summary:  Work on the Upper North Oconee Interceptor Phase 2B Project is taking place along the Greenway between College Avenue and Sandy Creek Nature Center.  The project scope includes 1,745 linear feet (LF) of 36” pipe and appurtenances, 1,300 lf of 60” tunnel, and 30 LF of trench installation.  The depth of the pipe varies from 30’ to 55’, with the deepest portion under the Bypass.

Click for PDF of map

Map of Upper North Oconee Interceptor Sewer Improvements

Project Update: The contractor has completed:

  • the river crossing, including pipe installations
  • all four shafts for tunnel boring machine (TBM) access
  • setting and stacking out manholes West Side of Oconee River
  • micro tunnel and pipe under Rail Road right of way
  • installation of storm drain system on Alexander Street under Rail Road right of way
  • main yunnel under Loop 10
  • installing 1170’ of 36” Ductile Iron Pipe in the tunnel
  • continuing work on Alexander Street, i.e. paving, inverts, and fence installation 

How this benefits Athens' residents:  This sanitary sewer project will improve the capacity of the UNO Interceptor, which will eliminate existing capacity issues and allow for expansion for industrial customers. The project will also move exposed aerial sewer pipe along the North Oconee River to under the Loop with the installation of a new tunnel.


Cutter head on the front of tunnel boring machineCutter Head on Front of TBMInstalling tunnel boring machine cutter head

TBM Re-installation
Operator station from inside the tunnel boring machine Operator Station Inside TBM

Hand-mining tunnel - contractor dug 45 ft by hand as Shaft #3 & 100 ft. at Shaft #1 
Hand Mining Tunnel

Installing the piers for the pipe crossing the riverDriving Piles River Crossing

Tunnel entrance to Shaft #3

Tunnel Entrance Shaft 3 (1)