Other Source Control Studies

The LMPS was a two-year field study conducted in the Los Angeles Metropolitan Area to assess the effectiveness of structural and non-structural Best Management Practices (BMPs) to reduce litter entering or discharging from the Caltrans freeway storm drain system. The structural BMPs focused on modifying freeway drain inlets. The non-structural BMPs focused on increasing the frequency of both street sweeping and manual litter pick-up programs. For each BMP, litter and water quality samples were collected and characterized at both a test and a control area and then compared.

OWP Tasks

• Assisted in Study Planning
• Reviewed Designs of Modified Freeway Drain Inlets
• Provided Monitoring Assistance
• Reviewed Data Assessment and Reporting

Report/Study Link: Caltrans Street Sweeping Study
OWP Contacts: David Alderete

The goal of the Tahoe Sweeper Study was to evaluate whether regenerative air/dustless sweeper technology is more effective than the department's current sweepers (mechanical) in collecting fine particles (smaller than 20 microns in diameter) from Caltrans roadways in the Lake Tahoe Basin. This study evaluated sweeper performance by comparing grain size distributions, fine particle counts, and the total amount of material collected by the different sweepers.

OWP Tasks

• Assisted in Study Planning
• Provided Monitoring Assistance
• Performed Small Particle Counts
• Analyzed Data and Statistics
• Reviewed Report

OWP Contacts: Scott Meyer

The primary objective of this study was to identify methods and products that might assist Caltrans in improving snow and ice control practices with minimal impact on the environment. This study involved interviewing Caltrans staff to identify current and past snow and ice control practices used by Caltrans, conducting a literature review to identify methods and products in use by other transportation organizations throughout the world, and assessing the feasibility of Caltrans implementing such products or methods.

OWP Tasks

• Assisted in Literature Review of Snow and Ice Control Practices Used by Others
• Assisted in Identifying Caltrans Current and Past Snow and Ice Control Practices
• Reviewed Documentation of Findings

OWP Contacts: Maureen Kerner

The primary objectives of this study were to 1) assess the water quality of highway runoff in areas where the deicer, IceSlicer®, is applied, and 2) compare it to the water quality of highway runoff from areas where traditional sand and salt applications are used. To achieve these objectives, highway runoff samples were collected and analyzed from areas where IceSlicer® was applied, and from areas where it was not applied but where traditional sand and salt practices were used instead. The water quality data from each area were then compared. Bulk samples of IceSlicer® were also collected and analyzed to assess the chemical composition of IceSlicer®. Finally, the amount of traction sand applied to areas where IceSlicer® was and was not applied was recorded and compared to document whether or not less traction sand is used when IceSlicer® is applied.

OWP Tasks

• Assisted in Study Planning
• Reviewed Design of Monitoring Systems
• Reviewed Monitoring Activities and Documentation
• Reviewed Data Assessment and Reports
• Conducted Laboratory Analysis of Fine Particles
• Documented Activities and Findings from Fine Particle Analysis

OWP Contacts: Maureen Kerner

This study was conducted by the University of California-Davis under the direction of Caltrans. The objective of the study was to assess the relative contribution of potential sources of fine particles within highway runoff in the Tahoe Basin. Runoff samples were collected from various locations and analyzed for their elemental composition. Results from the runoff samples were compared to the elemental composition of source bulk samples, and the relative distribution of each source was estimated. Potential sources of fine particles that were targeted included on-site soils, local vegetation, pavement wear, and traction sand.

OWP Tasks

• Assisted in Study Planning
• Assisted in Collection of Runoff Samples
• Reviewed Reports

OWP Contacts: Maureen Kerner

The Lake Tahoe Total Maximum Daily Load (TMDL) focuses on the impact of fine particles and nutrients on the clarity of Lake Tahoe. To better understand fine particle loads, this study collected and analyzed particle size distributions (PSDs) in highway runoff in the Tahoe Basin. The specific objectives were to provide preliminary estimates of the proportion of fine (< 63 µm) particle mass and total suspended sediment (TSS) concentrations in edge-of-pavement runoff. Six sites were identified and monitored. To determine the impact of improved traction sand application in recent years, the selected sites were the same as those monitored by Caltrans between 2000 and 2003.

OWP Tasks

• Assisted in Study Planning
• Provided Monitoring Assistance
• Analyzed Particle Size Distributions Using Laser Diffraction
• Reviewed Data Assessment and Reporting

OWP Contacts: Dipen Patel

The goal of this study was to assess various traction sand products that would be less susceptible to crushing under tire and chain wear, thereby reducing the amount of fine particles (< 16 µm) in highway runoff. Fine particles in highway runoff have been identified as a primary source of Lake Tahoe's clarity degradation. The study involved identifying abrasives that met Caltrans specifications, exposing the abrasives to simulated crushing, and analyzing the resulting fine particles. Twenty-two types of abrasives were collected and analyzed from suppliers within 100 miles of the Tahoe region.

OWP Tasks

• Assisted in Study Planning
• Analyzed Samples for Fine Particle Counts Using Flow Particle Image Analyzer
  (FPIA 3000)
• Provided Data Analysis and Reporting for Fine Particle Results
• Reviewed Study Results and Technical Memorandum

OWP Contacts: Scott Meyer