Step 7 - BRAT Combined Dam Capacity Model

After running the Vegetation Dam Capacity Model, you can run the Combined Dam Capacity Model tool. This fuzzy inference system model predicts the maximum number of dams each reach could support based on 4 inputs: 1) the output of the vegetation dam capacity model 2) the low (base) flow stream power, 3) the high flow (Q2) stream power, and 4) the slope of the reach. The model predicts dam capacity separately for historic vegetation dam capacity and existing vegetation dam capacity.


Inputs and Parameters:

  • Select Project Folder - path to the BRAT project folder
  • Input BRAT Network - select the BRAT network that you have been using up to this point
  • Maximum DA Threshold - this is a drainage area value above which it is assumed that the stream is too large for beaver to build dams on. This varies from region to region and should be adjusted according to the hydrologic characteristics of the study area.
  • Save Output Network - choose a location and name to save the output

The output network will be placed in a new folder in Output_## called 02_Analyses. The output network will have the new fields oCC_HPE (historic combined dam capacity) and oCC_EX (existing combined dam capacity). When the tool finishes running the second time it should automatically add the output to the map and symbolize the oCC_EX field, which represents the existing capacity to support dam building activity.

The fields oCC_HPE and oCC_EX are split into the following categories for our symbology:

  • None: 0 dams
  • Rare: 0-1 dams/km
  • Occasional: 1-5 dams/km
  • Frequent 5-15 dams/km
  • Pervasive: 15-40 dams/km

Layers are created with these symbologies in the folder 01_Capacity, which is placed in 02_Analyses.


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