Clarification on Calculating Areas

To clarify calculating the threshold for vegetation and algae control and animal pest control use patterns, Part II.A.1.(b)(ii) and Part II.A.1.(b)(iii) of the permit were revised to add the phrase “a treatment area” and now reads as follows:

“(ii) Vegetation and Algae Control- Operators treating a treatment area greater than or equal to 100 acres in water or greater than or equal to 200 linear miles at water’s edge;

(iii) Animal Pest Control- Operators treating a treatment area greater than or equal to 100 acres in water or greater than or equal to 200 linear miles at water’s edge;…”

For vegetation and algae control, and animal pest control the annual threshold is 100 acres or more of surface water or 200 linear miles or more at water’s edge, regardless of whether the operator is treating both sides of a river or stream.  These thresholds must be met or exceeded within a treatment area to qualify as Level I.

To calculate the surface acres treated, at least one treatment area must meet or exceed 100 acres. So, if a Pest Management Area (PMA) has two separate lakes that are being treated, the PMA would have two treatment areas.  Suppose Lake A is 50 acres and Lake B is 150 acres.  The operator treats 20 acres in Lake A and 70 acres in Lake B so the treatment would be 20 acres and 70 acres, respectively.  Neither treatment area meets or exceeds the 100 acre threshold so the operator would not be in Level I, regardless of the number of times these acres are treated.  However, if the operator treated 125 acres in Lake B this would exceed the annual threshold, putting the operator in Level I.

To calculate the linear miles at water’s edge, the calculation should include the linear extent of the application made at water’s edge within each treatment area, regardless of whether the operator is treating both sides of the river or stream.  For example, if each side of a river is treated and the operator treats 12 river miles, the treatment area remains 12 miles, regardless of whether they are treating one side or both sides of the river or stream. At least one treatment area must meet or exceed 200 linear miles.  Another example, if an operator has a linear PMA such as a right-of-way that is 100 yards wide, which crosses three (3) waters of the U.S., the operator will have 3 treatment areas, each 100 yards in length. None of the treatment areas meet or exceed the 200 linear miles. The three treatment areas are not added together.

These examples are intended to help the regulated community understand how to calculate treatment size to determine when the annual threshold is met or exceeded