State-of-the-Practice Review on the Use of Flocculants for Construction Stormwater Management in the United States

Construction stormwater practices have a vital role in protecting downstream water bodies from runoff that is typically characterized with large amounts of sediment and suspended solids. Most sediment control practices lack the capability to capture fine-sized soil particles that are responsible for causing elevated turbidity. Flocculation is a form of chemical treatment that uses flocculant particles as a binding bridge to form larger particles to enhance the gravitational settling process. The use of flocculants provides promising results for removing fine particles and treating construction stormwater. This study provides a comprehensive review of flocculants and their applications in construction stormwater treatment in the U.S. The study presents a literature review and results of a state-of-the-practice survey distributed to state departments of transportation. Results from 37 participating state agencies and data from specifications and design manuals for non-participating agencies were compiled to develop a comprehensive understanding of current uses and perceptions. Results indicated that 39% of state agencies currently use flocculants on construction sites. Within that, 54% of the state agencies rely on manufacturer guidance for dosage and application rates and only 23% require monitoring residual flocculant in downstream receiving waters. The potential risk of polluting downstream water bodies because of overdosage of flocculants related to inadequate application rates and techniques is the main concern of the state departments of transportation on flocculant usage. Understanding the perspective of the state agencies on flocculants will provide an insight into future research agendas for extending the use of flocculants in construction stormwater management.

  • Record URL:
  • Availability:
  • Supplemental Notes:
    • Some or all data, models, or code that support the findings of this study are available from the corresponding author on reasonable request. The following data sets are available: raw measurements collected during experimentation and photographs documenting experiments. © National Academy of Sciences: Transportation Research Board 2021.
  • Authors:
  • Publication Date: 2021


  • English

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 01765881
  • Record Type: Publication
  • Files: TRIS, TRB, ATRI
  • Created Date: Feb 22 2021 6:00AM