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Erosion Prediction with RUSLE2

Caltrans RUSLE2 Software

The Revised Universal Soil Loss Equation, version 2 (RUSLE2) is an advanced, user-friendly software model that predicts long-term, average annual erosion by rainfall. Modified as “Caltrans RUSLE2,” this software is streamlined for use on large, roadway construction projects and includes commonly used Best Management Practices (BMPs).

This version of Caltrans RUSLE2 (January, 2025) and Manual includes many enhancements, and includes the following objectives:

  • Provides a background on the fundamental concepts and processes related to soil erosion, such as rainfall, runoff, sediment transport, and deposition.
  • Provides an overview of what RUSLE2 is and how the program predicts erosion.
  • Demonstrates how to install and set up the RUSLE2 program files, including the Caltrans databases and templates.
  • Describes the user interface and instructs users on how to gather the necessary project data needed for RUSLE2 inputs.
  • Provides consistency with existing Caltrans manuals, procedures, policies, and practices for assessing project site conditions when identifying resources for collecting project-specific information needed for RUSLE2.
  • Demonstrates and explain how to navigate and use the RUSLE2 software interface, including inputting data, setting up scenarios, and interpreting results at the pre-construction, post-construction, and construction phases.
  • Provides consistency with documenting and reporting RUSLE2 findings for permit compliance.

Disclaimer

Whereas every effort has been made to incorporate accurate data into the Caltrans RUSLE2 software and databases, its empirical nature can only suggest annual averages of erosion and not exact amounts of sediment into receiving waters. Verify all Caltrans RUSLE2 results relying on sound engineering judgement. Caltrans does not guarantee or warrant that use of the Caltrans RUSLE2 software will assure regulatory compliance, you are to rely on your engineering judgement to establish regulatory compliance.

Terms of Use

Erosion Prediction Procedure

The Erosion Prediction Procedure (EPP) defines a method to predict erosion rates at construction sites. The EPP includes a series of steps to properly characterize project sites and facilitate more accurate evaluation of the anticipated erosion and the effectiveness of proposed soil stabilization and sediment control practices. The procedure introduces the concept of a Maximum Allowable Erosion Rate (MAER) for the construction and post-construction phases to establish a performance goal for comparing calculated erosion rates.