Stormwater particle size distribution & BMP effectiveness

A literature review project to gather up-to-date information on particles and contaminants in stormwater, and the best management practices to capture and treat them.


The Washington State Department of Natural Resources (WDNR) is working with Evergreen StormH20 to conduct this literature review project. The goals are to gather up-to-date information about the size of particles in stormwater, bound contaminants, and the effectiveness of a range of treatment approaches for those particle sizes.

Study questions

  • Gather information about the different methods to measure particle size distribution (PSD) and how do they compare?
  • What is more recently known about characterized sources, and nature of particle sizes and attached pollutants transported in the MS4 or delivered to BMPs?
  • What is the reported effectiveness of concentration or load reduction by stormwater BMPs as a function of PSD?

Study findings

This study is ongoing until November 2023.

Project tasks and deliverables

Scope of Work

Task 1:  Project administration and management

Task 2:  Literature search and synthesis

  • Deliverable 2.1 Synthesis of literature
  • Deliverable 2.2 List of data sources
  • Deliverable 2.3 Data summary tables

Task 3 Summarize, report, and communicate findings

  • Deliverable 3.1 Report outline
  • Deliverable 3.2 Draft flowcharts
  • Deliverable 3.3 Final flowcharts
  • Deliverable 3.4 Draft white paper
  • Deliverable 3.5 Final white paper
  • Deliverable 3.6 Draft fact sheet
  • Deliverable 3.7 Final fact sheet
  • Deliverable 3.8 Final SAM and local conference presentations