First Flush Phenomenon Characterization

This report describes the results of a study characterizing and quantifying the first flush of highway pollutants from three sites near the University of California, Los Angeles. It also reports on data collected at other sites in District 7. The study was conducted over four years and includes storms monitored from 1999 to 2003. First flush is a phenomenon that is associated with the belief that the first runoff in a storm even is the most contaminated. One area of focus in this study has been to develop a quantitative definition of first flush. In areas that have distinct seasonal rainfall patterns, such as California, a similar concept known as seasonal first flush exists. The study has developed a mathematical concept that can be applied to different types of first flush phenomenon. Another area of focus for the study was in estimating the mass first flush of highway emissions, with the objective of proposing methods for improving the effectiveness of best management practices (BMP) that take advantage of the first flush. Additional investigations of the study included: water quality during storm events, litter characteristics, correlations among contaminants, first flush of organics, litter and particles, models for the build up and washoff of pollutants, new methods for measuring oil and grease, and grab and composite sampling strategies.


  • English

Media Info

  • Media Type: Print
  • Features: CD-ROM; Figures; Illustrations; Tables;
  • Pagination: v.p.

Subject/Index Terms

Filing Info

  • Accession Number: 01014961
  • Record Type: Publication
  • Source Agency: UC Berkeley Transportation Library
  • Report/Paper Numbers: CTSW-RT-05-073.02.6
  • Contract Numbers: 443A0073
  • Created Date: Dec 1 2005 3:12PM