S Terwilliger Sewer and Lift Station Project

Sewer and Stormwater
Environmental Services is designing a project to replace approximately 450 feet of public sewer pipe and install a sanitary lift station on S Terwilliger Boulevard just north of S Northgate Avenue. Unstable ground conditions pose a risk of the pipe failing. This project will address this.
The project is currently in design. Construction is anticipated to begin in the summer of 2023 and take up to six months to complete.

Project Area

The map below illustrates the project location. 

Project Background

In 2017, Environmental Services installed a new sewer line on S Terwilliger Boulevard from S Powers Court to Highway 43. Several months after construction was completed, a sag was discovered in the section located west of S Northgate Avenue (east of Powers Court and west of Castleridge Lane). That section of pipe is not operating according to design standards. It requires frequent and costly cleaning and maintenance, and the pipe is at risk of failing. Engineers suspect that a mix of very soft soils and high groundwater at this location caused the pipe to sag. A sag in a pipe can slow or prevent sewage from moving through the pipe. The ground conditions in this location create a further risk of the pipe failing completely.

What is a Lift Station?

A lift station “lifts” sewage and wastewater up to a higher elevation and discharges it to a new maintenance hole and sewer line. This is different than a pump station, which pumps the sewage and wastewater over some distance through a force main pipe to a treatment plant. The lift station will lift sewage and wastewater up to a new pipe that is in more stable soil. The lift station will be located underground. An electrical control panel and radio antennae will be located above ground, along with a parking space for maintenance access.

What’s Happening Now

In early April, crews will be investigating underground conditions and locating utilities near the existing sewer pipe. They will drill holes at the side of the road to take soil samples. What the engineers learn from the analysis of soil, rock, and pavement samples will help them determine construction methods and locations.

What to Expect

Soil sampling is expected to take up to two days to complete. Work will occur during the day between 7 a.m. and 6 p.m. Monday through Friday. Temporary lane closures with flaggers will be necessary during work hours, so traffic delays are expected.

There may be brief periods of noise, dust, and mild vibration during drilling. When soil sampling is complete, crews will fill in the holes.

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