Improving ditches & maintenance

Roadside ditches are prevalent, and required maintenance is expensive, which leads to delays and potential build-up of water quality contaminants. This project will evaluate maintenance and retrofit techniques such as reshaping and planting plans to reduce long-term costs and optimally improve stormwater quality. In this project, the Washington State University — Puyallup (WSU-P) will test retrofitted ditch shapes and plant palettes for improved pollutant removal, conveyance of higher storm flows, and lower long-term maintenance effort. 

Study questions

  • Can alternative plant palettes mitigate pollutant loads and peak flows in roadside ditches?

Study findings

This study is ongoing until April 2024.

Project tasks and deliverables

Scope of Work, Amd 1

Task 1: Project management

Task 2: Quality Assurance Project Plan (QAPP)

Task 3: Site instrumentation of 3 ditches

Task 4.0: Evaluating alternative planting palettes  

  • 4.1: Draft report including total effort associated with the successes and failures of the vegetation plantings.
  • 4.2: Final Report

Task 5.0: Quantifying effects ditch maintenance and retrofit on water quality and quantity  

  • This task was removed by Amendment 1 due to lack of suitable study locations

Task 6.0: Communication of findings

  • Stormwater Work Group presentation and a regional stormwater related conference or workshop 
  • Draft SAM fact sheet