DEP WQI Interactive Mapper

PA WQI v.2019

1. DEP’s Water Quality Index (WQI) uses concentrations of 21 physicochemical parameters to index an overall score from 1-100 (poor-good). The results are based on how similar a site’s water quality is to water quality dominated by one of four major land use/covers, referred to as Sub-WQI (SWQI) scores. The lowest SWQI of the four is considered “most similar” and subsequently is used to drive the WQI score.

• A manuscript has been published that describes the development of PADEP’s WQI (Wertz and Shank, 2019): https://esajournals.onlinelibrary.wiley.com/doi/full/10.1002/ecs2.2947*

2. Sites are color coded based on WQI score grades. A simple click on a site of interest will produce a pop-up window with:

• The SWQI driving the WQI score, the average-annual WQI score, grade (Good, Average, Fair, or Poor)
• Year collected, n (number of samples taken that year)
• Additional location information including monitoring point alias and GNIS ID
• If >1 years of data have been collected at the site, points will appear stacked in chronological order (most recent year on top) when you zoom in. Click each point to show temporal changes (or possibly trends) in water quality through time.

Interactive WQI map

3. The primary message here is WQI score/grade – grey/black in areas of intense landscape development and white/light grey in areas of large contiguous forests (e.g., PA Wilds). The secondary message is years and SWQI driver.

4. The current WQI dataset contains 2,869 annual averages for 1,406 unique COMIDs from 2009-2019.

• A total of 18,061 discrete samples were used to calculate annual averages at all sites.

• This map is shareable at the following link: https://rpubs.com/mattshank20/depWQI2019

*The PA WQI v.2019 was been modified from the original manuscript during recalibration/synchronization events. Subtle shifts in WQI/SWQI scores may be noted and the grade for “good” was adjusted to ≥ 80.