Services > Environmental Modeling > Model Development > PRZM

Pesticide Root Zone Model

The Pesticide Root Zone Model (PRZM) is a one-dimensional, finite-difference model that accounts for agrochemical and nitrogen fate in the crop root zone. PRZM3 includes capabilities for modeling the effects of soil temperature, volatilization and vapor phase transport, irrigation, and microbial transformation on agrochemicals in the soil. The model also includes the method of characteristics (MOC) algorithm to eliminate numerical dispersion. PRZM is capable of simulating transport and transformation of the parent compound and as many as two daughter species.

Waterborne staff have been involved with the development and enhancement of PRZM since the model’s inception.

VADOFT is a one-dimensional, finite-element code that solves the Richard's equation for flow in the unsaturated zone. The user may make use of constitutive relationships between pressure, water content, and hydraulic conductivity to solve the flow equations. VADOFT may also simulate the fate of two parent and two daughter products.

The PRZM and VADOFT codes are linked together with the aid of a flexible execution supervisor that allows the user to build loading models that are tailored to site-specific situations. In order to perform probability-based exposure assessments, the code is also equipped with a Monte Carlo pre- and post-processor.

US PRZM

PRZM3 is USEPA’s Tier 2 agrochemical leaching model that is a required component in Tier 2 analysis. Waterborne staff have been involved with the development and enhancement of PRZM since the model’s inception. Although all official model development is now performed by USEPA, Waterborne continues to offer customized programming of PRZM at the request of our clients to meet their ever-changing research needs.

The latest official version of the PRZM3 model can be downloaded from the USEPA Exposure Assessment website. For customized versions of the model, please contact us or go to our model download page.

EU PRZM

PRZM in FOCUS is the European version of PRZM developed by Waterborne staff for the EU FOCUS group to handle standard scenarios. Special PRZM versions for groundwater and surface water were developed.

The EU versions of PRZM can be downloaded from the EU FOCUS group website.

PRZM Enhancements

Our past and present involvement in the development of PRZM provides unparalleled experience using this model for runoff and leaching studies worldwide. Learn more about enhancements made by Waterborne to the PRZM model.