Hayden Lake

LINK TO DECISION MATRIX
 

HOW TO USE THE DECISION MATRIX

The decision matrix was designed to aid planning for control efforts for Eurasian watermilfoil.  The decision matrix will compute approximate amount of herbicide, benthic barriers or time required for some form of diver hand-pulling for each infestation input into the matrix program for up to 10 infestations.  Use the web-based tool to compute the size of the infestation and then enter the additional information requested for each infestation into the matrix along with the infestation size.  Download the Decision Matrix file to your computer and save.  The first two columns of the matrix are filled with sample information to show how the matrix computes the best control options for the given information.  Before you begin adding your project information, clear the fields from the sample columns.  The matrix program will also compute approximate costs for each infestation and each possible treatment.  You will need to save each 10 infestations to a separate file using the Save As command in Excel. (see flow chart)

The data fields that you enter include:

1. Infestation identification label (optional, replace the 1 to 10 numbers across the top),

2. Infestation size in acres,

3. Eurasian watermilfoil density class,

4. Average depth of water for the infestation, entered in feet.

The top of the spreadsheet is where you enter your data into the matrix program.  You also can change the costs of each potential treatment; in the yellow box at the bottom of the matrix.  The rest of the matrix program is protected from entry.  For most treatments there are at least high and low control inputs listed and in some cases specific concentrations are provided.  The units of measure are included so that you know what units are represented in the calculations.  Users do not need to access the second page of the spreadsheet, as it is there to support calculations for the front page.

If infestations are large, then benthic barriers and diver assisted control are not presented as options and so there are some decisions made based on infestation size and approximate plant density.  Plant density is categorized using one of four options: scattered = 1, light = 2, moderate = 3 and high = 4.  The density categories are:  scattered equals one EWM plant per 100 sq. yards; light density equals one EWM plant per 10 sq. yards; moderate density equals one EWM plant per 1 sq. yard; and high density equals six plants per 1 sq. yard.

In future versions, additional guidance will be provided with respect to restrictions related to applications of herbicides including amount of a water body that can be treated at a single time, required distance from water intake to avoid shutting down water pumping, and approximate duration of treatment before resuming water use.