Tier Selector

Use this quick guide to choose a tier based on effort and decision risk:

  • Screening: many sites, low risk, desktop data.
  • Rapid: moderate risk, field day per site.
  • Detailed: high risk, intensive data and calibration.

Screening tier | Rapid tier | Detailed tier

Screening

When to use

  • Watershed screening and prioritization
  • Early project planning across many sites
  • Low-risk decisions where higher uncertainty is acceptable

What you get (outputs)

  • Function scores with clear uncertainty notes
  • Outcome indices (physical, chemical, biological)
  • Ranked list of candidate reaches for follow-on tiers

What it costs (effort/resources)

  • Minutes to hours per site
  • Primarily desktop time with optional field verification
  • Minimal specialized equipment or lab analysis

Typical data inputs

  • GIS land cover and impervious surface
  • Remote sensing and imagery
  • National datasets and existing reports

Rapid

When to use

  • Comparing multiple candidate sites
  • Alternatives evaluation or conceptual design support
  • Validating Screening-tier results with field evidence

What you get (outputs)

  • Semi-quantitative function and outcome scores
  • Structured field observations with photo documentation
  • Clear comparison across reaches and alternatives

What it costs (effort/resources)

  • Hours to one day per reach
  • Trained field staff and standard field kit
  • Limited lab analysis

Typical data inputs

  • Structured field forms and checklists
  • Simple channel and habitat measurements
  • Screening-tier metrics for context

Detailed

When to use

  • High-risk decisions and regulatory compliance
  • Mitigation crediting or debiting
  • Post-construction monitoring and performance verification

What you get (outputs)

  • Defensible, lower-uncertainty function scores
  • Calibrated reference curves and thresholds
  • Full documentation suitable for review

What it costs (effort/resources)

  • Multiple days to weeks per site
  • Specialized equipment, lab analysis, and modeling
  • Higher staffing and QA/QC requirements

Typical data inputs

  • Intensive field surveys and monitoring
  • Water quality and biological sampling
  • Regional reference datasets and models