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# Four Main Steps - PowerPoint PPT Presentation

Four Main Steps. Select and group indicators Transform measured data into unit-less scores Aggregate scores from multiple indicators into a summary index Define breakpoints to bin index scores into descriptors of condition (grades or colors) . Central Coast Region Preliminary Indices.

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Presentation Transcript

• Select and group indicators

• Transform measured data into unit-less scores

• Aggregate scores from multiple indicators into a summary index

• Define breakpoints to bin index scores into descriptors of condition (grades or colors)

Central Coast RegionPreliminary Indices

• Human Health WQ Index

• Aquatic Life WQ Index

• Toxicity Index

• Bioassessment Index

• Biostimulatory Risk Index

• Habitat Index

• Riparian Index

Magnitude and Exceedance Quotient (MEQ)

Combines two terms that express number of threshold exceedances and magnitude of exceendance.

Derived from Canadian Ministry of Governments method

We are scoring all tests, not just failed tests. This provides a “good” end to the scoring tool

We eliminated the scope term (how many analytes fail) because we have inconsistent data availability across sites.

We do the calculations at the level of the analyte so that each analyte can also be scored

Calculating MEQ, cont.

Calculate magnitude (amplitude) for each individual analyte (from CCME)

Calculate unitless sample magnitudes:

Magnitude = concentration/threshold

Calculate normalized sum of magnitudes

NSM = Σ magnitudes / sample count

Scale from 0 – 100

= NSM / (0.01*magnitude average+0.01)

Combine exceedanceand magnitude factors and scale to 100 (modified from CCME)

MEQ = 100 – √exceedance2 + magnitude2

1.414

• Basic water quality – Mean average

• Biostimulation – Mean average

• Metals for aquatic life – Harmonic Mean

• Organic chemicals for aquatic life – worst score

• Human health – worst score

• Overall site score – Harmonic Mean or worse index score (?)

• Assembled thresholds from Marshack, U.S. EPA benchmarks, and other sources

• Established criteria for threshold selection

• Marshack algorithms

• Health not harm (“threshold” effects)

• Consistency within chemical group

• Selected thresholds for aquatic life (cold, estuarine, and marine) and human health (drinking water and water body contact) in sediment and water

• CCAMP, SWAMP, Central Coast Ag data, Grant data

• GAMA/Geotracker

• Pesticide use database

• National land cover dataset

• Aquatic Life

• Conventional water quality

• Bioasssessment

• Biostimulation (floating mats, chlorophyll a (water column

• Organic chemistry (sediment and water)

• Metals (sediment and water)

• Hydrocarbons (sediment and water)

• Toxicity (sediment and water)

• pH departure

• Water temperature

• Nitrate

• Total and unionized ammonia

• Ortho-phosphate

• Total suspended solids

• Turbidity

* Note currently no dissolved solids

• Oxygen departure

• Chlorophyll a (water column)

• % floating mats

• NNE oxygen deficit

• NNE predicted benthic chlorophyll biomass (using threshold of 44 mg/m2)

Human Health (includes drinking water and water body contact)

• Salts

• Nitrogen species

• Organic chemicals

• Hydrocarbons

• Metals

• Pathogen indicators

Factor 1: Scope

Factor 2: Frequency

Factor 3: Amplitude

CCME WQ Index

Quadratic mean (or root mean square) gives greater weight to larger values, thus emphasizing excursions.

Pro: + widely excepted (esp. for drinking water)

+ considers scope, frequency, amplitude

Con: - resolution to detect differences among sites or times depends heavily on standards selected

- Not as useful for characterizing “healthy” because it only looks at failed tests

- Scope is susceptible to site variability in number of analytes tested (best for very consistent study design)

Calculate rate of exceedance (frequency) for each individual analyte (from CCME)

Factor 1: Frequency

F1

F1