EQUIS Trend Station Explorer

http://gisonline.dep.wv.gov/equis/equis.html

The most extensive online database of surface water quality in West Virginia is the DEP's EQUIS Trend Station Explorer.  The DEP regularly tests 235 locations in streams and rivers throughout the state for a wide variety of water quality measures, including some heavy metals.  All this data is displayed in a beautiful mapping program publicly available online... if you know where to find it.  You won't find this link on the DEP's website or anywhere else, but it is one of the most useful tools around.  There are test results from 2002 on.
 
Navigation
When you open the page you will see a map of West Virginia and lots of multicolored dots.  Each dot is a testing site (“trend station”).  You can double-click to zoom in and there is a bar on the right to control zoom level.  Click and drag to move the map around. 
 
At the top, there are two words with drop down menus:
- The one on the left controls whether the background image is aerial photography or USGS topo maps.
- The one on the right controls what test results you are looking at (Dissolved Oxygen, Iron, pH, etc).
 
The color of each trend station is determined by the average level of whatever is selected above with green being the lowest and red being the highest.  Mousing over a trend station will display the trend station number, number of times the selected parameter has been tested for, the minimum test result, the average test result, the maximum test result, and the standard deviation in that order.
 
Sample Data
Clicking on one of the trend stations will highlight the basin drained by the stream above the trend station and display the average test result for the selected parameter.  A window will also pop up with a list of sample dates and number of parameters tested for each time.  Clicking on a row will give you all the testing results from that date.  Be sure to note the units for each result.  Look at the “Fraction” column to see which results are “Dissolved” and which are “Total”.  “Total” measures suspended metals; “Dissolved” measures dissolved metals.  Unfortunately, for most metals they only test for “Total”.  Just because all the “Total” tests come back clean for a metal does NOT mean there isn't a significant amount of that metal dissolved in that stream.   The sample data window can also be opened by clicking the first button from the left.
 
Scatterplot
Click the second button from the left for a graph with all the test results for the selected parameter by date.  You'll have to click “Get Results” after the window pops up to see any data.  The only annoying thing is that when both “Total” and “Dissolved” tests for the same metal are done, all the results show up together with no clear way to distinguish between them.
 
Bar Graph
Click on the third button from the let for a list of all the trend stations in the state sorted highest to lowest by average test result for the selected parameter.  Mousing over a bar gives you the same information as mousing over the trend station dot and clicking on a bar will zoom the map to that trend station.
 
Filter
Click on the fourth button from the left to filter out all trend stations with average results above or below a certain threshold.
 
Search Feature
Click the fifth button on the left to search the map for any named place.  Clicking on a result will zoom the map to that location.