Ladd’s Addition Green Street and Sewer Project

Sewer and Stormwater
Environmental Services constructed a project that installed and upsized public sewer pipes, as well as constructed green street planters, within the Ladd’s Addition neighborhood. These improvements increase sewer capacity, relieve sewer backups, and reduce street flooding.
Construction is almost complete and is in the final stages of restoration.

Project Area

The map below illustrates where this project has constructed sewer improvements, green street planters, and new ADA ramps. The map also shows the methods of construction.  

Simplified map of Ladd's Addition sewer and green street project with methods of construction

General Schedule

Work hours are from 7 a.m. to 6 p.m., Monday through Fridays, with work possible on Saturdays if needed. The city’s contractor, Landis & Landis will provide advance notice at least 5 to 10 days to adjacent properties before construction begins at each work zone.  

What’s Happening Now

All work is weather-dependent and subject to change.

Remainder of week of April 2:

Construction will occur during work hours between 7 a.m. and 6 p.m., Monday through Friday at the following locations: 

  • All green street retrofits are completed.
  • Sewer connections to properties are being lined with Cured-in-Place-Pipe Lining (CIPP) along SE Hickory Street Alley between SE Orange and 16th avenues.
  • Paving in miscellaneous areas of the project area.

Week of April 15:

Construction will occur during work hours between 7 a.m. and 6 p.m., Monday through Friday at the following locations: 

  • Paving is tentatively scheduled (weather dependent) for SE Harrison and SE Hemlock streets.

Green Street Retrofits

There have been many reports of several of the green streets being full of stormwater. Green streets are intended to fill up with water when it rains, then overflow back into stormdrains once they are full. They are designed to slowly drain water down into the soil. When the plants are more established, the green streets will drain faster. In Ladd's Addition, we have discovered that there are more compacted and clay-like soil layers that are not allowing some of the facilities to drain as fast as they should be if at all. When a green street appears to be slow draining, as we are seeing in some of the newly constructed green streets, we gather additional information and determine whether corrective measures are needed to address the issue. 

In November 2023, Environmental Services investigated several locations and determined that seven (7) of the green streets that were either not draining or draining too slowly. These planters have been revised/retrofitted. The seven green street planters as seen on the map below were drained, saturated soils were removed as needed, one or two 8-inch diameter perforated PVC pipes were inserted at various depths, and then backfilled with a 1/4-inch rock. The depths of the perforated pipe vary from 8 to 17 feet depending on the depth of the sandy gravel reached. The green street planters will be monitored by staff. 

The seven green street planters that have been retrofitted are located:

  • SE Tamarack Ave between SE Lavender and Division
  • SE Lavender St east of SE Tamarack Ave
  • SE Tamarack Ave northwest of SE Lavender St
  • SE 16th Ave south of SE 16th Ave
  • (Two) SE Ladd Ave north of SE Lavender
  • SE Larch Ave south of SE Mulberry Ave
Ladd's Addition Green Street with Drainage Retrofits

What to Expect During Construction

A brief guide on what you can expect during construction projects conducted by Environmental Services and their contractors can be found at Construction Impacts.

We Want to Hear From You

Please let us know if you have any questions regarding the sewer pipes or green street planters. Be sure to include your name, property address, and project name (Ladd’s Addition) in your voicemail and email so we can provide you more details about what to expect in front of your property. Also, please write “Ladd’s Addition” in the subject line of your email.

Construction Methods

The city plans to use two different methods to construct this project:

  • Open trench excavation is the most traditional and most common method of sewer construction. This method consists of excavating down to and exposing the existing pipe (if there is one), so that it can be installed, repaired, or replaced. The trench is then backfilled and temporarily paved until the pipe is quality control tested.
  • Cured-in-Place Pipe Lining (CIPP) is a trenchless method of sewer construction. It requires little or no digging and significantly less time to complete than other sewer repair methods. CIPP involves inserting a flexible liner inside the existing pipe, inflating the liner, and exposing it to heat or ultraviolet light to “cure,” or harden the liner inside the pipe.

Learn more about construction methods.

Project Background

The purpose of this project is to relieve basement sewer backup risk, reduce street flooding, and overall risk to the large sewer trunk in the project area. To that end, this project will upsize or repair portions of the public sewer main line to increase its capacity to handle combined sewer and stormwater. It will also build green street planters that help slow, filter, and cleanse stormwater from the streets.   

The project is designed to accomplish the following sewer and stormwater improvements:  

  • Relieve basement sewer backups at 59 properties.  
  • Replace or repair 3,500 feet of public sewer mainline pipe, ranging in size from 8 inches to 14 inches in diameter.  
  • Construct 15 green street planters. 
  • Construct or replace 9 sewer connections that connect private sewer lines to the public sewer in the street; this will involve 300 feet of lateral sewer pipe.  
  • Construct or replace 15 maintenance holes.  
  • Replace 6 stormdrains and construct 336 feet of stormdrain pipe.
  • Construct 11 ADA ramps.

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This project will help protect the health of the Willamette River Watershed.