Birch Bay Projects

Cottonwood Drive Stormwater Improvements Project

Project Update (9/25/17): Two weeks down and about a week left on the Cottonwood Drive Stormwater Improvements project. Last week, we focused on establishing the new, wider stream channel. This week we removed a section of the old outlet pipe and put the new structures in place, including a new inlet pipe, catch basin and outlet pipe that connected to the existing storm main. The installation went smoothly and Iverson Earth Works, LLC worked with care as they moved the large concrete structures into place. You may notice the material covering the slopes in some of the pictures; this was in place to protect the exposed soil from erosion during the rain we had on Tuesday. Once the new structures were installed, we began backfilling and compacting the material around the pipes. Next week, we will focus on building a berm around the overflow structure, seeding the hillslope and cleaning up the surrounding facilities. Stay tuned for more progress pictures!

Collaborative Drainage System Repair on Birch Point

Construction on this project was completed in September 2016.

Project Goals

  • Replace a failing stormwater outfall pipe subject to overflow.
  • Significantly reduce the risk of flooding and erosion on a steep bluff.
  • Address a priority safety problem

Project Description

This project replaced a stormwater system that carries flows from central Birch Point under Semiahmoo Drive and across Washington State Department of Natural Resources (DNR) property to Semiahmoo Bay. This area is subject to high flows during winter storms. The previous outfall pipe was undersized and became overwhelmed during storm events, causing flooding and erosion on the beach bluff and threatening homes on DNR leased land. this was collaborative project funded by BBWARM and other Whatcom County Public Works funds.

The new drainage system includes:

  • A larger cross culvert under Semiahmoo Drive.
  • A new outfall pipe anchored above the fragile beach bluff.
  • A new energy dissipater at the end of end of the outfall pipe.