Operational Plan for the Restoration of Diadromous Fishes to the ...

Parr density (no. / 100 m 2 )
45
40
35
30
25
20
15
10
5
0
0 200 400 600 800 1,000 1,200 1,400 1,600
The GIS-based habitat model used slope, cumulative drainage area and
physiographic province to predict Atlantic salmon rearing habitat throughout Maine.
Stream widths were estimated using regional hydraulic curves for Maine rivers. We
used the Penobscot basin portion of this dataset. We then compared reaches that
were surveyed using field methods to the model predictions. This revealed 1) the
model is conservative, habitat was either predicted at or below the levels observed
in the field (Figure 4), and 2) errors in predicting stream width accounted for about
75% of the variability in the difference between field observations and model
predictions (Figure 5).
Figure 4. Field verses modeled habitat data with perfect prediction reference line
(one to one).
Model Habitat Units
16000
14000
12000
10000
8000
6000
4000
2000
Field verses Modeled Habitat Data- Penobscot Basin
Field to Model
One to One
Cumulative drainage area (sq km)
Linear (Field to Model)
0
0 2000 4000 6000 8000 10000 12000 14000 16000
Field Survey Habitat Units
Aroostook Dennys
East Machias Kennebec
Machias Narraguagus
Pleasant Penobscot
Saco Sheepscot
75th Quantile 90th Quantile
PRFP Page 143