Chlorophyll-a Time Series & Spatial Maps Management Target vs. Regulatory Threshold Distinction

[esherwoo77]

For chlorophyll-a, there's particular distinction between the management 'Target' levels (i.e. TBEP identified desirable levels) and the regulatory 'Threshold' levels (i.e. FDEP-adopted values for the purposes of assessing impairment for the TB bay segments.) The FDEP regulatory thresholds equate to the target level + 2 S.E. (i.e. the upper reference line for chl-a), and not attaining the thresholds for 2 concurrent years has direct ramifications for permitted entities represented in the TBNMC. There's a history to this that goes beyond the 2000 document that discusses the development of these various cut-points.

[fawda123]

Changed the legend in the function that produces these plots: tbep-tech/tbeptools@715b1bf

Also changed some of the headers on the dashboard.

Now "target" only refers to the lower of the three values and threshold refers to +2se (the higher of the three values).