Environmental Engineering Reference
In-Depth Information
Habitat
parameter
Condition category
Optimal
Suboptimal
Marginal
Poor
6. Channel
alteration
Channelization or
dredging absent or
minimal; stream with
normal pattern.
Some channelization
present, usually in areas
of bridge abutments;
evidence of past
channelization, i.e.,
dredging, (greater than
past 20 years) may be
present, but recent
channelization is not
present.
Channelization may be
extensive; embankments
or shoring structures
present on both banks;
and 40%-80% of stream
reach channelized and
disrupted.
Banks shored with gabion
or cement; over 80% of
the stream reach
channelized and disrupted.
Instream habitat greatly
altered or removed
entirely.
Score
20
19
18
17
16
15
14
13
12
11
10 9876543210
7. Channel
sinuosity
—e bends in the stream
increase the stream length
3 to 4 times longer than if
it was in a straight line.
(Note - channel braiding
is considered normal in
coastal plains and other
low-lying areas. —is
parameter is not easily
rated in theses areas.)
—e bends in the stream
increase the stream length
1 to 2 times longer than if
it was in a straight line.
—e bends in the stream
increase the stream length
1 to 2 times longer than if
it was in a straight line.
Channel straight;
waterway has been
channelized for a long
distance.
Score
20
19
18
17
16
15
14
13
12
11
10 9876543210
Banks stable; evidence of
erosion or bank failure
absent or minimal; little
potential for future
problems. <5% of bank
affected.
Moderately stable;
infrequent, small areas of
erosion mostly healed
over. 5%-30% of bank in
reach has areas of erosion.
Moderately unstable; 30%-
60% of bank in reach has
areas of erosion; high
erosion potential during
floods.
Unstable; many eroded
areas; “raw” areas
frequent along straight
sections and bends;
obvious bank sloughing;
60%-100% of bank has
erosional scars.
8. Bank stability
(score each bank)
Left bank
Right bank
Score
—
Score
—
(RB)
(LB)
10
9
8
7
6
5
4
3
2
1
0
10
9
8
7
6
5
4
3
2
1
0
More than 90% of the
streambank surfaces and
immediate riparian zone
covered by native
vegetation, including
trees, understory shrubs,
or nonwoody
macrophytes; vegetative
disruption through grazing
or mowing minimal or not
evident; almost all plants
allowed to grow naturally.
70%-90% of the stream-
bank surfaces covered by
native vegetation, but one
class of plants is not well-
represented; distruption
evident but not affecting
full plant growth potential
to any great extent; more
than one-half of the
potential plant stubble
height remaining.
50%-70% of the stream-
bank surfaces covered by
vegetation; disruption
obvious; patches of bare
soil or closely cropped
vegetation common; less
than one-half of the
potential plant stubble
height remaining.
Less than 50% of the
streambank surfaces
covered by vegetation;
disruption of streambank
vegetation is very high;
vegetation has been
removed to
5 centimeters or less in
average stubble height.
9. Vegetative
protection (score
each bank)
Note: Determine
left or right side
by facing
downstream.
Score
—
Score
—
(RB)
Left bank
Right bank
(LB)
10
9
8
7
6
5
4
3
2
1
0
10
9
8
7
6
5
4
3
2
1
0
10. Riparian
vegetative zone
width (score
each bank
riparian zone)
Width or riparian zone
>18 meters; human
activities (i.e., parking
lots, roadbeds, clear-cuts,
lawns, or crops) have not
impacted zone.
Width of riparian zone 12-
18 meters; human
activities have impacted
zone only minimally.
Width of riparian zone 6-
12 meters; human
activities have impacted
zone a great deal.
Width of riparian zone <6
meters; little or no
riparian vegetation due to
human activities.
Score
—
Left bank
Right bank
(LB)
10
9
8
7
6
5
4
3
2
1
0
(RB)
Score
—
10
9
8
7
6
5
4
3
2
1
0
To tal score
FIGURE 7.6
Example of a rapid bioassessment ield data sheet for habitat (back page), for low gradi-
ent streams. (From Barbour, M.T., Gerritsen, J., Snyder, B.D., and Stribling, J.B.,
Rapid Bioassessment
Protocols for Use in Streams and Wadeable Rivers: Periphyton, Benthic Macroinvertebrates and Fish
, U.S.
Environmental Protection Agency, Ofice of Water, Washington, DC, 1999.)
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