Science & Technology

Stressor-Response: Calculation

Simple linear regression is the recommended approach for estimating relationships between stressor and response within groups of water bodies.

Stressor-Response: Classification

To classify water bodies for stressor-response analysis, you identify groups of water bodies that have similar stressor-response relationships.

Data Overview

Data are the foundation for developing effective nutrient criteria that result in healthy water environments that meet their designated uses.

Mechanistic Modeling: Classification

The nutrient criteria development process uses a classification system to clarify variability of water bodies that exist across the country.

Mechanistic Modeling

This page provides an overview, with four successive pages that provide more detail on mechanistic modeling and how states can use mechanistic models to derive numeric nutrient criteria.

Stressor-Response

Stressor-response modeling is used when data are available to estimate a relationship between nutrient concentrations and a response measure.

Mechanistic Modeling: Configuration & Calibration

In addition to gathering and entering appropriate data into the model, you also must establish the model’s spatial extent and specify the size of its computational cells, or reaches.

Mechanistic Modeling: Simulation

After you set up the model, you can run scenarios at different nutrient concentrations.

N-STEPS Online Resource Library

References, resources, and data sources to aid in planning and developing numeric nutrient criteria.

Communicating Final Criteria

Once candidate criteria have been derived, and final criteria selected, it is important to be able to clearly communicate how the final criteria are protective of designated uses.

Quantifying and Documenting Protection of the Designated Use

The two elements comprising the process of deriving numeric nutrient criteria—quantifying and documenting the level of protection that is necessary to protect the designated use—rely on the analytical results of a particular approach.

Criteria Derivation

Elements and key technical considerations associated with estimating nutrient conditions and water quality indicators of those conditions that will protect designated uses.

Waste Reduction Model

To help solid waste planners and organizations track/report GHG emissions reductions from various waste management practices. To assist in calculating GHG emissions of baseline and alternative waste management practices and provide the history of WARM.

FSTRAC Newsletter

Information related to FSTRAC Newsletter.

Scientific Integrity

EPA's Scientific Integrity Policy promotes scientific and ethical standards, including quality standards; communications with the public; the use of peer review and advisory committees; and professional development.

Exposure Assessment Resources (ExpoBox)

EPA's ExpoBox is a collection of tools to help risk assessors perform exposure assessments or risk characterizations using step-by-step instructions and provides links to all the latest EPA guides, databases, and models using a state-of-the-art database.