Water Quality Program - Nitrate Groundwater Pollution Hazard Index

Find Your Index Number (this feature is currently under repair - expected to return early May 2008)

Purpose: To provide information for farmers to voluntarily target resources for management practices that will yield the greatest level of reduced nitrogen contamination potential for groundwater by identifying the fields of highest intrinsic vulnerability.

How it Works: The index works with an overlay of soil, crop, and irrigation information. Based on the three components, an overall potential hazard number is assigned and management practices are suggested where necessary. If you don't know what soil type you have, try this online soil survey with detailed soil survey data for much of California, Arizona, and Nevada.

More Information:

• Hazard Index Concept (background information & process) (pdf, 54kb)
• Supporting Evidence for the Nitrate Groundwater Pollution Hazard Index Concept (pdf, 49kb)
• Concentration versus Mass Flow (pdf, 61kb)
• Irrigation Principles (pdf, 49kb)
• Dynamics of Nitrogen Availability and Uptake (pdf, 124kb)
• Basic Factors Affecting N Transport through Soils (pdf, 107kb)
• Interpretation of Nitrate Groundwater Pollution Hazard Index Number (pdf, 42kb)
• Workshop Presentations:
  • Background Information and Supporting Evidence for the Hazard Index (pdf, 154kb)
  • Basic Factors Affecting N Transport through Soils (pdf, 263kb)
  • Hazard Index Ratings for Soils: Methodology and Examples (pdf, 78kb)
  • Hazard Index Ratings for Crops: Methodology and Examples (pdf, 381kb)
  • Hazard Index Ratings for Irrigation Systems (pdf, 168kb)