Design Guide for Roadside Infiltration Strips in Western Oregon

Roadside infiltration strips, also called vegetated filter strips, have the ability to decrease the immediate impact of road runoff on nearby streams and agricultural fields. Though there is a rich history of research on the chemical and physical filtering capabilities of these structures, total infiltration capacity is often not the focus of these research efforts. By using dimensional analysis of a varied infiltration capacity dataset, this research developed a new design equation and subsequent design chart to simplify and streamline the infiltration strip design process. Given that the parameters and variables used in this design process are freely available in map form, a preliminary analysis of all roads within the western corridor of Oregon could be performed in geographic information systems (GIS) for future filter width design. The design equation was created by the following process. 1) A network of roadside infiltration observation plots was constructed and operated for 2 years. The network consisted of five plots arranged in a transect from the Oregon coast to the Cascade foothills. Within each plot, rainfall, soil moisture, soil water content and total runoff from the observation area were recorded every 15 minutes and averaged into daily infiltration intervals; 2) Semi-empirical relationships between the road geometry, the soil physical properties, and the local climate were explored with dimensional analysis; 3) Final groupings of variables were found, collapsing the data to a single semi-empirical relationship. This relationship is the design equation. For practical design applications, a specified range of variables was used to turn the design equation into a design chart. This report is divided into 4 sections. An introduction and general background is presented in Section 1, followed by a detailed description of each study sited is presented in Section 2. In Section 3, summary statistics and time series of the data are presented. In Section 4, the rationale and logical process to create the design equation is outlined, and the ultimate design equation and design chart is given. The report is concluded with an example calculation of a roadside filter strip width.

• Record URL:
  http://www.oregon.gov/ODOT/Programs/ResearchDocuments/SPR758_DesignGuide_InfiltrationStrips_FinalReport.pdf
• Record URL:
  https://rosap.ntl.bts.gov/view/dot/37671
• Corporate Authors:

  Oregon State University, Corvallis

  Department of Biological and Ecological Engineering
  Corvallis, OR  United States 

  Oregon Department of Transportation

  Research Section
  555 13th Street NE
  Salem, OR  United States  97301

  Federal Highway Administration

  Washington, DC  United States 
• Authors:
  • Higgins, Chad
  • Liu, Ziru
  • Stewart, Ryan
  • Kelley, Jason
  • Drake, Steve
• Publication Date: 2016-6

Language

• English

Media Info

• Media Type: Digital/other
• Edition: Final Report
• Features: Appendices; Figures; Maps; Photos; References; Tables;
• Pagination: 134p

Subject/Index Terms

• TRT Terms: Design; Geographic information systems; Infiltration; Roadside; Runoff; Time series analysis; Vegetation; Width
• Geographic Terms: Oregon
• Subject Areas: Environment; Highways; Hydraulics and Hydrology;

Filing Info

• Accession Number: 01603566
• Record Type: Publication
• Report/Paper Numbers: FHWA-OR-RD-16-16
• Contract Numbers: SPR 758
• Files: TRIS, ATRI, USDOT, STATEDOT
• Created Date: Jun 28 2016 4:41PM