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title: "WQX QAQC Service User Guide"

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author: "TADA Team"

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## TADA Leverages the Water Quality eXchange (WQX) QAQC Service

This is a overview of the the WQX Quality Assurance and Quality Control

(QAQC) data submission service, and how TADA leverages that service to

flag potentially suspect data in the Water Quality Portal (WQP). It will

cover: 1) an overview of all available WQX QAQC tests for data

submissions, 2) which of these QAQC tests are also available in TADA for

flagging potentially suspect WQP data, and 3) how to interpret and

provide feedback on the validation reference tables referenced by WQX

and TADA for this QAQC service.

## Background

The WQX expectation for submissions is that users submit only QAQC'd

data and utilize WQX elements to ensure the data is of "documented

quality". The WQX team has historically hosted data quality working

groups aimed at creating best practices and required data elements for

WQX 3.0 for specific parameter groups such as nutrients, metals and

biological data. These resources have supported users to submit data of

documented quality. This approach has been broadly successful, but

because it is not an enforceable approach it has allowed for data of

varying quality to be shared. In response, the WQX team recently

released a QAQC service in 2022 to test and flag data submissions for

potential errors, and provide the data submitter with a chance to make

edits to improve the quality of their data, before it goes into the WQP.

However the new WQX services will not flag or fix data historical that

is already in the WQP. Therefore, the TADA R package leverages the WQX

QAQC Validation Reference tables in the R package to make these same

tests available on WQP outbound data using R.

## Available Tests

Tests available in both WQX Web for data submissions & the TADA R

Package for use with data retrieved from the WQP:

- Tests that Leverage the WQX Validation Table

- Flag suspect characteristic and unit combinations (e.g., flag

data if mg/L or °C was used for pH; flag if units were left

blank, NA, None, etc. but are required for the characteristic)

- [TADA_FlagResultUnit()](https://usepa.github.io/EPATADA/reference/TADA_FlagResultUnit.html)

- Flag data without methods, with uncommon methods, or with

suspect methods for the characteristic. This is contingent on

the activity type since some activity types don't require

methods.

- [TADA_FlagMethod()](https://usepa.github.io/EPATADA/reference/TADA_FlagMethod.html)

- Flag data with suspect characteristic and fraction combinations

- [TADA_FlagFraction()](https://usepa.github.io/EPATADA/reference/TADA_FlagFraction.html)

- Flag data with suspect characteristic and speciation combination

- [TADA_FlagSpeciation()](https://usepa.github.io/EPATADA/reference/TADA_FlagSpeciation.html)

- Flag monitoring locations with imprecise coordinates (accuracy

of lat/long is less than three three decimal degrees (e.g.,

38.88°, -77.00°)] and/or coordinates outside of the US.

- [TADA_FlagCoordinates()](https://usepa.github.io/EPATADA/reference/TADA_FlagCoordinates.html)

- Flag results that do not have an approved QAPP and/or do not

include a QAPP attachment

- [TADA_FindQAPPDoc()](https://usepa.github.io/EPATADA/reference/TADA_FindQAPPDoc.html)

- [TADA_FindQAPPApproval()](https://usepa.github.io/EPATADA/reference/TADA_FindQAPPApproval.html)

- Flag results above or below national thresholds using the

Interquartile Range (IQR) method. The IQR method is defined as

the difference between the 75% percentile and the 25% percentile

of your dataset.

- Upper Threshold= 75th Percentile + 1.5 \* (75th percentile -

25th percentile)

- [TADA_FlagAboveThreshold()](https://usepa.github.io/EPATADA/reference/TADA_FlagAboveThreshold.html)

- Lower Threshold= 25th Percentile - 1.5 \* (75th percentile -

25th percentile)

- [TADA_FlagBelowThreshold()](https://usepa.github.io/EPATADA/reference/TADA_FlagBelowThreshold.html)

[ with an

interquartile range and normal

[probability](https://en.wikipedia.org/wiki/Probability_density_function).

Attribution: [Jhguch](https://creativecommons.org/licenses/by-sa/2.5/)

via Wikimedia

Commons.](images/IQR.png)](https://commons.wikimedia.org/wiki/File:Boxplot_vs_PDF.svg)

Additional tests only available in WQX Web and Node Submissions:

- Location

- Flag data where the lat/long assigned to monitoring sites is NOT

in the state and country included in metadata.

## Providing Feedback on Validation Tables

All WQX Domain Tables are available

[HERE](https://www.epa.gov/waterdata/storage-and-retrieval-and-water-quality-exchange-domain-services-and-downloads).

TADA leverages many of the WQX domain tables.

- [QAQCCharacteristicValidation

(ZIP)](https://cdx.epa.gov/wqx/download/DomainValues/QAQCCharacteristicValidation_CSV.zip) \|

([XML](https://cdx.epa.gov/wqx/download/DomainValues/QAQCCharacteristicValidation.zip)) 

\|

([CSV)](https://cdx.epa.gov/wqx/download/DomainValues/QAQCCharacteristicValidation.CSV)

- Both WQX and TADA leverage the table above to flag suspect and

uncommon results. This reference table is used in the following

TADA functions:

- [TADA_FlagAboveThreshold()](https://usepa.github.io/EPATADA/reference/TADA_FlagAboveThreshold.html)

- [TADA_FlagBelowThreshold()](https://usepa.github.io/EPATADA/reference/TADA_FlagBelowThreshold.html)

- [TADA_FlagResultUnit()](https://usepa.github.io/EPATADA/reference/TADA_FlagResultUnit.html)

- [TADA_FlagMethod()](https://usepa.github.io/EPATADA/reference/TADA_FlagMethod.html)

- [TADA_FlagFraction()](https://usepa.github.io/EPATADA/reference/TADA_FlagFraction.html)

- [TADA_FlagSpeciation()](https://usepa.github.io/EPATADA/reference/TADA_FlagSpeciation.html)

- [MeasureUnit

(ZIP)](https://cdx.epa.gov/wqx/download/DomainValues/MeasureUnit_CSV.zip) \|

([XML](https://cdx.epa.gov/wqx/download/DomainValues/MeasureUnit.zip))\| [(CSV)](https://cdx.epa.gov/wqx/download/DomainValues/MeasureUnit.CSV)

- Both WQX and TADA leverage the table above to convert all data

for each unique characteristic to a consistent unit, so that

results can then we assessed against the WQX upper and lower

thresholds in the validation table. Target units for each

characteristic are included in the MeasureUnit domain table.

TADA leverages this table to convert all data for each unique

characteristic to a consistent target unit. See relevant TADA

functions:

- See TADA Function:

[TADA_ConvertResultUnits()](https://usepa.github.io/EPATADA/reference/TADA_ConvertResultUnits.html)

All TADA Reference and Validation Tables are also available in the R

Package

[HERE](https://github.com/USEPA/EPATADA/tree/develop/inst/extdata). TADA

pulls the WQX Validation Table and other domain tables into TADA and

updates them automatically whenever changes are made. WQX and TADA users

can review and provide feedback on the validation table and/or target

units assigned, and provide feedback by emailing the WQX helpdesk

(WQX\@epa.gov).