Natural Riparian ResourcesVegetationLandscape/SoilWater
Vegetation is the second leg of the triangle. It is provides the
rebar for the streambanks with deep strong root system. It provides
protection to the soil surface with the leaves and stems. It helps
filter sediment and build banks. There are seven questions that
pertain directly vegetation. Questions 6 and 10 are important as to
the relative health of the important riparian plants. Questions 7
through 9 are not an amount rather they are presents or absence.
Question 11 is the amount.At this point, we need to discuss
riparian-wetland vegetation and some of the functional groups. For
our purposes today, we will group the riparian plants into three
groups, colonizers, stabilizers, and increasers/Invaders. The
definitions for colonizers and stabilizers are from Dr. Alma
Winward, US Forest Service, Ogden, Utah. Increasers/invaders were
added because these species are important indicators of current
riparian conditions.Grasslike Plants
Beaked sedge (Carex rostrata), is one of the most common
stabilizer plants in riparian areas at mid to low elevations in
Idaho. It is very aggressive if given an opportunity and provides a
large amount of forage.
Beaked sedge develops a continuous buffer for water energy along
Upper Portnuef River. By the way, sedges have triangular stems. I
learned it by "sedges have edges."
Wire grass or baltic rush (Juncus balticus) the dark areas on
the slide is a common riparian plants. It will help stabilize with
an extensive and strong root system, but also will thrive in a
little drier conditions. Baltic rush in the darker colored plants
in this picture.
Wire grass or baltic rush again has extensive root that are hard
to dig up. Rushes have round stems. I learned the saying "rushes
are round." Here we have an example of the extensive root system
under baltic rush. Note the amount, depth, and size of the
roots.Stabilizers
Plant species that become established along the waters edges of
streams, rivers, ponds, and lakes. They also become established at
springs and seeps where ground water provides the necessary wet
conditions. Some can persist in drier conditions once they are
established. These plants commonly have strong, cord-like rhizomes
and deep fibrous root masses. The root masses along with the
typically coarse leaves and strong crowns are able to protect
streambanks from the erosive forces of water. These same
characteristics filter sediment and with the forces of water build
or rebuild eroded portions of streambanks. They also are important
to improving water quality. These species play an important role in
properly functioning riparian areas and aquatic ecosystems
Many of the important riparian stabilizing species are not true
grasses. They area classified as grass-likes that include the
sedges and rushes.
This chart provides an indication of the amount of above ground
biomass to the below ground. Riparian vegetation has a root to
shoot ratio of over 3 to 1. Meaning that there is more than three
times as much growing vegetative material below ground as there is
above. This is compared to the dry or upland site which has a ratio
of about 1.5 to 1. Here we can see a comparison of the wet, moist,
and dry plants root system. At all levels, there is almost two
times as much root mass as the moist and dry plants. The sedges
(Carex) are one of the important riparian species. They are
characterized by solid triangular stems with leaves that are
3-ranked or come of the stem on three sides. The leaves are usually
relatively wide. As a result, I learned that sedges have edges.
These are some of the common growth characteristics of sedges.
The sedges we will discuss usually have well distributed leaves.
The seeds are usually distributed along the stem also.
The stabilizers have rhizomes or underground stems that produce
new plants. We will discuss four species common to much of Idaho.
In reality it is not iThis picture is of beaked sedge, a common
sedge in the mid elevations. Note the wide leaves and the seed
heads distributed along the stems.
This is a typical growth location in very wet soils along the
stream and in low places where the water table is very shallow.
Nebraska sedge (Carex nebraskensis), is one of the most common
stabilizer plants in riparian areas at mid to low elevations in
Idaho. It is very aggressive if given an opportunity and provides a
large amount of forage.
Nebraska sedge develops a continuous buffer for water energy
along Birch Creek. It is the bluish colored plant. By the way,
sedges have triangular stems. I learned it by "sedges have
edges."
Rushes or wire grass has a solid or compressed stem that appears
to be solid. The leaves are compressed or two-ranked. As I learned
it Rushes are round. So now we have sedges with edges and rushes
are round.
There are various growth forms, but we are interested in the
rhizomatous plants the develop course deep roots, such as baltic
rush.This is wire grass or Baltic rush. It is usually a less
preferred feed by livestock, but it is very effective in erosion
control on streambanks.
This is a typical growth pattern. Rushes usually grow in
slightly drier sights than sedges. Although it is not uncommon for
them to grow on the streambank. Especially in a recovering stream.
In saturated conditions, sedges will gradually replace the
rushes.Here we have an example of the extensive root system under
baltic rush. Note the amount, depth, and size of the roots.
There are a few true grasses that are important streambank
stabilizers. They are are different from the grass-like plants we
just discussed in that the leaves are two ranked and the stems are
hollow. The stems also have nodes (joints) and space between the
nodes called internodes.
The stabilizing species we will discuss are whose with
rhizomes.Fowl mannagrass (Glyceria striata) shown here is one of
the stabilizing grasses. Mannagrass stabilizes rapidly as shown in
this slide on Crow Creek. It develops a dense root system and a
good greenline. Here the mannagrass is growing in recently high
water deposition.
Blue joint reedgrass (Calamagrostis canadensis) is a native
species that has a deep tough fibruousroot system that stabilizes
streambanks. This is an example of a reedgrass community on Little
Sand Creek in northern Idaho.
Another stabilizer is Reeds canarygrass (Phlaris arundicinacea).
There is disagreement as to whether it is a native or introduced
species. It has been used as a pasture grass in the past. Although
it is effective for streambank stabilization and very aggressive,
it can become a weed problem along many waterways. Woody
Species
Willow, alder and birch are typical woody communities that
provides an extensive and tough root systems. They provide
excellent streambank stability. Willow communities most frequently
occur on coarser textured soils. They stabilize streams and filter
sediment making condition for herbaceous plants.
Geyers willow (Salix geyeriana) in combination with sedges make
the highest protection possible by vegetation. On low gradient
systems, herbaceous species can provide adequate protection. Many
riparian areas have several species of willow in them.
Willow roots are very deep (six feet plus) and strong. It
protects the banks and dissipates water energy. Some like to say
that coarse willow roots act as rebar.
Some common woody species include willow, alder, birch, and
dogwood.Colonizers
Colonizers or pioneers are plant species that establish in
freshly deposited soil or they may establish in the shallow open,
barren areas and are often the first plants to occupy open sites.
They can establish along the edge of a stream in slow moving
fringes along a stream or pond. They are usually rhizomatous or
stoloniferous with shallow roots and relatively weak stems.
Although some of the plants are short lived, they grow very
rapidly, up to an inch and a half per day. Their root systems catch
fine sediment and hold it in place so the more permanent stabilizer
species can replace them. It is part of the streambank building
process. Another apparent function of colonizers is to narrow the
channel during low flows allowing sufficient current to keep
sediment moving through the channel. These plants play a critical
role in the recovery and maintenance of stream channels.
Some common colonizers are:
Brookgrass (Catabrosia aquatica) a very shallow rooted rapid
growing (up to 1 inches per day) colonizer. It traps sediment and
provides habitat for stabilizers in which to establish roots. This
grass will also establish in good condition streams at low water,
narrowing the channel even more, allow sediment to be flushed
through the system. The grass is usually removed during high flow
events.
At lower elevations, common spike rush (Eleocharis palustris))
is a common colonizer. It establishes along the stream margin in
slow water and filters sediment. Spike rush is more permanent than
some of the other colonizers with moderately strong root systems
and are more difficult for stabilizers to move into. Here on
Shoshone Creek spike rush has narrowed the stream. If Nebraska
sedge is established, the rhizomes will penetrate the spike rush
and very slowly replace it. On Hardtrigger Creek the spike rush is
the dominant vegetation in the early stages of recovery, but can
withstand high flow events.
Water foxtail (alopecurus geniculatus) a colonizer of fine
sediment. It can be found along the shallows and still water along
streams. It is a tufted grass, without rhizomes. Thus, it only
begins to prepare the site for stabilizer species. It is common
from mid elevations up.Water-cress (Rorippa naturtium-aquaticum) is
a broadleaf plant that most of are familiar with. Again it will
establish along the stream margin in shallow water and can go into
the stream. It collects fine sediment and narrows the stream in low
flow and allow much sediment to pass through the system. It
provides hiding cover for fish.Coyote or sandbar willow (Salix
exigua) usually starts in gravel or sandy soils. It has a wide
spread shallow root system that sends up shoot, thus does not form
a clump. It will form very dense colonies which is unique among
willows in Idaho. It filters sediment and provides habitat for
other stabilizers.
Another colonizer is cottonwood (Populus spp.). It must have
damp freshly deposited soil for the seed to germinate and
establish. Here on the South Fork Snake River which has a regulated
flow, age classes show a several years differences. Only after the
floods in 1997, cottonwoods sprouted and became established along
the South Fork Snake River after the 1997 floods. You can also see
the linear patterns showing the bare ground habitat associated with
flood deposition.
Increasers/Invaders
Increasers are plants species that are more tolerant of
disturbance or heavy grazing. Plant communities in many of our
riparian areas have species that fit into this group.
Increasers and invaders have shorter, shallower, and less
massive root systems. Thus, they have less ability to protect
streambanks, dissipate energy, and filter sediment. They usually
produce few pounds of forage, although Kentucky bluegrass is very
palatable.
Invaders are plant species that invades or rapidly increases
following disturbance or heavy grazing or noxious weeds may invade
any plant community.
Examples of increasers and invaders include:
Two common increasers are Kentucky bluegrass (Poa pratensis) and
red top (Agrostis stolonifera). Both are shallow rooted rhizomatous
sod forming grasses. They are very palatable for livestock and
tolerates grazing. They are poor streambank stabilizers, will
dominate drier sites and with proper management, stabilizers will
replace much of the Kentucky bluegrass.
Other common increasers/invaders include fox tail (Hordeum
jubatum), Russian olive (Elaeagnus angustifolia), and Woods rose
(Rosa woodsii). Other common increasers/invaders include fox tail
(Hordeum jubatum), Russian olive (Elaeagnus angustifolia), and
Woods rose (Rosa woodsii).
Noxious Weeds
Noxious weeds are a concern riparian areas. Disturbed area
without dense, deep rooted plants provide an area for weeds to
germinate. Because of potential water contamination, there is only
a limited number of chemicals that can be used. Here leafy spurge
is invading a riparian community.
Purple loosestrife shown invade disturbed areas and are very
difficult to control. Healthy riparian vegetation can help control,
probably not eradicate, many of the these species. Noxious weeds
should be addressed in each riparian or allotment management
plan.
Question 6 - There is diverse age-class distribution of
riparian-wetland vegetation (recruitment for maintenance and
recovery)
Purpose
For a riparian-wetland area to recover or maintain itself, it
has to have more than one age class of riparian-wetland plants.
This question is not asking whether all possible age classes are
present; it is asking whether the number of age classes that
provide recruitment for maintenance of an area or to allow an area
to recover are present. Most riparian-wetland areas will recover or
maintain themselves with two age classes, as long as one of the age
classes is young (recruitment) and the other is middle-aged
(replacement). Older age classes (mature) usually take care of
themselves, as they are well-attached to existing water tables.
Older age classes can persist even with degraded conditions.
Examples
For riparian-wetland areas that require woody vegetation to
achieve functionality, a yes answer would be given if there are
seedlings and saplings present on the reach being assessed. A no
answer would be given if either recruitment or replacement
age-classes are absent.
Here Castle Creek has only a single age diversity of riparian
vegetation. The answer would be no
Answering question 6 for riparian-wetland areas that only need
herbaceous vegetation to achieve functionality is a little more
difficult. Many plants expand or colonize a site by stem and root
extension (e.g. Nebraska sedge). If there is dense matting of
herbaceous plants the answer to question 6 would be yes. If there
are individual plants of Nebraska sedge scattered along a reach
being assessed, the answer to question 6 would be no. The same can
be said for questions 7-11.
Many riparian-wetland areas have potential for both woody and
herbaceous vegetation. If a combination of woody and herbaceous,
either young, and/or middle aged, plants are present the answer to
question 6 would be yes.
It is important to note that this question if for evaluating
diverse age class for riparian-wetland vegetation, not for upland
vegetation. For example, if an area being assessed contains six age
vegetation, not for upland. For example, if a area being assessed
contains six age-classes of upland plants, the answer to question 6
would be "no." The same can be said for questions 7-11.
An "N/A" answer would apply for channels that are entrenched and
confined in bedrock (e.g. Al channel type-Rosgen 1996).This picture
shows at least two age-classes of willows.This slide of Shoshone
Creek shows multiple age-classes of willow and a continuous mat of
sedges indicating reproduction and Question 7-There is diverse
composition of riparian-wetland vegetation (for
maintenance/recovery)
Purpose
Not only does a riparian-wetland area require a diverse age
class, it has to have a diverse composition of vegetation present
if is going to maintain itself or recover. This question is not
asking whether all the plants that an area can support are
present.
The intent of question 7 is to document that species composition
present is sufficient for maintenance or recovery. For most
riparian-wetland areas, this means having two or more
riparian-wetland species present, depending on site potential
and/or capability. The presence of only one species makes a site
very vulnerable to disease or extreme changes in climate, which may
result in degradation of an area. There are some areas, though,
that will have only one species, but these are uncommon and usually
limited as a result of a unique soil property, vegetative
characteristics, or water regime.
Examples
Areas such as shown in this slide of Cedar Creek shows the
diverse vegetation on a healthy riparian area. This is typical of
healthy riparian-wetland areas. We can see rushes, sedges, at least
two kinds of willows and aspen.
There are no stabilizing species in this picture. The tall
plants are annual forbs.Here there is willow, sedge, and fowl manna
grass.Here there is 3 or 4 species of willow, at least two species
of sedges, and rush. A healthy riparian area.Question 8 - Species
present indicate 'maintenance of riparian-wetland soil moisture
characteristics
Purpose
The intent of this question is to look for evidence that the
water table level is being maintained or is moving towards its
potential extent as indicated by the presence of riparian-wetland
vegetation. Recovering an existing water table is vital to the
maintenance or recovery of a riparian-wetland area.
Riparian-wetland plants are divided into categories relative to
their likelihood to occur in wetlands or nonwetlands (e.g., Reed
1988). These categories are Obligate Wetland (OBL), Facultative
Wetland (FACW), Facultative (FAC), Facultative Upland (FACU), and
Obligate Upland (UPL). Obligate wetland and Facultative wetland
plants are usually indicators of maintaining the water table.
Facultative plants are not good indicators and facultative upland
and obligate upland plants would indicate a lowering of the water
table.
Plants that occur in wetlands are hydrophytes, and they have
contact with the water table, which is why they can be used as
indicators of soil moisture characteristics.
Species present indicate the level of the water table is being
maintained. This example of riparian vegetation along Emery Creek.
Riparian-wetland species include sedges, rushes, and willows.
Notice the sagebrush, an obligate upland plant, is dying near the
stream, an indication the riparian area is maintaining or raising
its level.
The deed incision will lower the water table. The willows in the
background have a deep root system and may live for many years, but
will not reproduce under these conditions. The current water table
is associated with the stream and on the terrace or upper level. Be
sure to recognize the appropriate level for the water table under
the current climate and geomorphic features.Question 9 - Streambank
vegetation is comprised of those plants or plant communities that
have root masses capable of withstanding high streamflow events
Purpose
The intent of question 9 is to document that the right plants or
community types are present on the streambanks for recovery and
maintenance of the riparian-wetland area.
Streambanks dominated by vegetation that lacks extensive root
masses are undercut during high flow events and collapse. This
collapse results m a change in the active channels width/depth
ratio, gradient, and sinuosity, which reduces a riparian-wetland
areas ability to dissipate energy. Most plants that are OBL and
FACW have root masses capable of withstanding high-flow events,
while most plants that are FACU or UPL do not.
The streambank is the area between bankfull and the channel
bottom. The terrace wall is the area above the floodplain.
Examples
Riparian-wetland species, such as willow, alder, aspen, birch,
and cottonwood, and or deep- rooted herbaceous species, such as
sedges, rushes, bulrush, and some wetland grasses, have root masses
along the streambank capable of withstanding high flow events. If
the plants dominate plant communities along a streambank, the
answer to question 9 would be yes. An exception would be for
intermittent systems. For many intermittent systems the community
domination of FAC plants is all that is required for a "yes"
answer, as this is all these systems can produce.
Here, on Castle Creek there is a dominance of Kentucky
bluegrass, there are sedges and willow along the stream that do not
provide the streambank protecting measures of the riparian species,
the answer is Yes, because there are willow and Nebraska sedge,
very low vigor, along the streambank.
Some species, such as Kentucky bluegrass, redtop, blue grama,
and sagebrush, do not have the root masses capable of withstanding
high-flow events. If these plants dominate plant communities along
a streambank, the answer to question 9 would be "no."
There are exceptions, such as high gradient, bedrock, or
boulder/cobble stream types (Rosgen 1996), where the vegetation
community contributes little, if any, to bank stability. For these
the answer would be "N/A."
The bank is eroding or has only Kentucky bluegrass or redtop
along the streambank. The answer is no.PurposeThe intent of this
question is to ascertain if riparian-wetland plants are healthy and
robust or weaken/stressed and leaving the area. The above ground
expression is reflection of the below-ground and ability for
riparian-wetland species to hold the area together. As
riparian-wetland plants weaken or leave an area, the is subject to
degradation.This slide shows the difference in the root growth
associated with vigor of the above ground part of the plant. On the
far left, the plant has been continually clipped to a short height,
may be one inch. Not that the individual plants are obvious with
little root growth. Other characteristics of low vigor in sedges
are relatively narrow leaves, individual plants are distinct with
leaves growing close to the ground. It take adequate leaves above
the ground to maintain a strong healthy root system.If we look at a
cross-section of the stream, this is where we would find the
greatest water velocity. As you can see, this is the area of
greatest root concentration of the stabilizing species. Shallow
rooted species allow the water to use its energy on the soil
underneath the vegetation.This question is very important, but is
difficult to answer. For most riparian-wetland areas, plant size,
shape, and leaf color during the growing season can be used to
discern vigor. For example, if the willows for a given reach are
well-rounded and robust, the answer to question 10 would be "yes."
If these same plants are highlined/mushroom- shaped, contain a lot
of decadent material, etc., the answer to question 10 would be
"no.
Another example of a "no" answer would be if the willow leaves
are turning yellow during the growing season. This usually happens
as a result of water being removed or added to a system, which
stresses the plants. However, change in color can also indicate a
disease problem or climatic factors.
Abundance of herbaceous plants can be used to assess vigor. If
Nebraska sedge composes a dense mat on the reach being assessed,
the answer to question 10 would be "yes." If Nebraska sedge occurs
as isolated plants or broken clumps not forming communities, the
answer to question 10 would be "no."
"N/A" would be used for channel types that have no potential to
produce vegetation.
Are the herbaceous stabilizer (late seral) species obvious
individual plants? Yes Are there new stabilizing herbaceous plants
around the perimeter of the mat? NoAre leaf blades of the sedges
relatively wide? NoAre non-rhizomatous woody species short with
over 10 stems at the base? Do woody specie have a club look,
multiple branching, at the end of the stems?Are the herbaceous
stabilizer (late seral) species obvious individual plants? Are
there new stabilizing herbaceous plants around the perimeter of the
mat? Are leaf blades of the sedges relatively wide? Are
non-rhizomatous woody species short with over 10 stems at the base?
Do woody specie have a club look, multiple branching, at the end of
the stems?
Shrubs show severe hedging and very little growth. Herbaceous
riparian vegetion is sparce with narrow leaves and individual
plants instead of wide leaves and dense mat.
Are the herbaceous stabilizer (late seral) species obvious
individual plants? Are there new stabilizing herbaceous plants
around the perimeter of the mat? Are leaf blades of the sedges
relatively wide? Are non-rhizomatous woody species short with over
10 stems at the base? Do woody specie have a club look, multiple
branching, at the end of the stems?Question 11 - Adequate
riparian-wetland vegetation cover is present to protect banks and
dissipate energy during high flows
Purpose
Vegetation filters sediment, aids floodplain development,
protects streambanks, etc., all of which dissipate stream energies
associated with high flow events. But this can only happen if there
are enough plants. The purpose of this question is to determine if
there is an adequate amount of vegetation present to dissipate
stream energies from high flow events.
This question is crucial for areas where vegetation is required
for proper functioning. For a riparian-wetland area to recover,
composition of the right plants, recruitment, etc., are necessary,
but until the right amount is present, the riparian-wetland area
will not cross the threshold that would allow it to function
properly.
It is important to understand that question Il deals with an
amount, while questions 6-10 deal with composition, age class,
etc., not amount. Generally question 11 will be answered no if one
or more of the other vegetation questions are answered no.
Riparian plants are the glue or resin that holds streambanks
together. They very strong and can resist the forces of water. This
maintains productive and diverse plant species that provide for the
many values that we have learned the riparian areas provide.
Mary Manning in a Masters research project provides some
indication of the mount of roots under some sedges, grass, and
rush. Note the miles of roots in a cube 12"X12"X16" under Nebraska
sedge, baltic rush, Douglas sedge, and Nevada bluegrass. Nebraska
sedge has about 22 miles compared with baltic rush with about 8
miles. Douglas sedge, that is similar to Kentucky bluegrass (Mary
Manning, Personal communications) is about 6 miles. The difference
between Douglas sedge and Baltic rush is the baltic rush as much
coarser roots with fewer fine roots.
Although the length of the roots under Baltic Rush appears much
less (Root Mass Graph), when the roots were weighed, there is not
the disparity between baltic rush and Nebraska sedge. This shows
that the roots are larger with fewer fine roots. As a result, this
is one of the stabilizing species.Dr. Alma Winward has developed a
list of riparian communities and their relative root strength or
their ability to withstand water energy. The scale is from 1 to 10,
with one being bare ground and 10 being anchored rock. You can see
the strength of willow/sedge communities compared to Kentucky
bluegrass or even willow/Kentucky bluegrass.Dr. Winward developed
capability groups that can give you a good idea of the amount of
riparian wetland vegetation cover needed to adequately protect a
stream. It is based on the slope and streambank material type. One
of the handouts provide this information.
First determine the stream gradient or slope and second the
streambank material. For example, the stream gradient is between 2
and 4 percent gradient with non-consolidated silt, sand or clay is
group VI. This indicates an need for at least 80% of the streambank
covered with vigorous riparian-wetland vegetation, coble, rock, or
anchored coarse or large wood.Are the streambanks covered with
sufficient stabilizing species to protect it from them from erosion
(See Winward 2000, p34)? Is the stabilizing riparian vegetation
adequate on the floodplain? Are the stabilizing species vigorous
(see question 10)?
For a wide, flat valley bottom with a sinuous channel, 90 to 95
percent cover of streambanks within a reach may be required. If an
area has the appropriate percent cover of riparian-wetland plants,
the answer to question 11 would be "yes." For other valley bottom
types, stream types, with different site potential a streambank may
only need 80 percent cover for the answer to be "yes."
Streambank vegetation such as this sedge and willow provide
adequate cover for streambank protection. These this community
provides the toughest root system of any riparian plant
community.
Inadequate cover of deep rooted riparian plants leads to
streambank erosion. Kentucky bluegrass and other plants with
relatively shallow root systems do not afford protection to the
streambank.
Are the streambanks covered with sufficient stabilizing species
to protect it from them from erosion (See Winward 2000, p34)? Is
the stabilizing riparian vegetation adequate on the floodplain? Are
the stabilizing species vigorous (see question 10)?
Here we can see the lack of stabilizing vegetation and the
effects of livestock use making false banks that are susceptible to
damage by high stream flows.
If a streambank for a reach being assessed is dominated by
upland plants, the answer to question 11 would be "no." If this
same streambank is 50 percent riparian-wetland plants and 50
percent upland plants, the answer to question 11 would still be
"no."
N/A" would be used for channel types that do not need vegetation
to achieve PFC.
Question 12 - Plant communities are an adequate source of coarse
and/or large woody material (for maintenance/recovery)PurposeStream
side and upland vegetation produces the size of woody material over
time to capture bedload, aid floodplain development, and dissipate
energy where appropriate for stream size and ecological setting
where woody material is required. Without course and/or large wood,
these areas cannot handle normal high_flow events because of their
intensity. This wood has to be large enough to stay for a period of
time to operate as a hydrologic modifier. This is usually at least
4 inches in diameter and 4 feet long. Willow, alder, and birch are
not usually considered coarse wood.
Before answering question 12, it has to be determined if large
wood in necessary for a given area to function properly. Many
rangeland and meadow riparian-wetland areas do not require woody
material to maintain channel stability.
Is the reach capable of growing trees, e.g. cottonwood, aspen
and conifers? YesIs large or coarse debris a necessary hydrologic
controls? Yes Is the site dominated by stabilizing shrub species?
Yes Has the site had the trees removed from the site? NoAre there
trees growing within one tree height of the stream channel? YesIs
the reach capable of growing trees, e.g. cottonwood, aspen and
conifers? Is large or coarse debris a necessary hydrologic
controls? Yes Is the site dominated by stabilizing shrub species?
NoHas the site had the trees removed from the site? YesAre there
trees growing within one tree height of the stream channel? No Is
the reach capable of growing trees, e.g. cottonwood, aspen and
conifers? Yes, CedarIs large or coarse debris a necessary
hydrologic controls? YesIs the site dominated by stabilizing shrub
species? NoHas the site had the trees removed from the site? YesAre
there trees growing within one tree height of the stream channel?
No
This would be a no.
Example
If course and/or large woody material is necessary and there are
trees present, it is important to then ascertain if they are
sufficient in number and size. If a reach contains a adequate
number of mature trees and they are large enough to serve as
hydrologic modifiers, the answer to question 12 would be "yes."
Some streams like Big Sand Creek in northern Idaho require large
wood to help dissipate energy.
If a stream reach requires large wood and there are no living
mature trees present that will access the stream in the future,
then the answer to question 12 would be "no." If there is only an
isolated tree here and there, the answer to question 12 would still
be "no."
This question will be answered N/A" for many channel types
throughout the West, as course and/or large wood is not required
for the stream to dissipate energy and to function properly.
Is the reach capable of growing trees, e.g. cottonwood, aspen
and conifers? Yes, Cottonwood, conifersIs large or coarse debris a
necessary hydrologic controls? YesIs the site dominated by
stabilizing shrub species? NoHas the site had the trees removed
from the site? YesAre there trees growing within one tree height of
the stream channel? No
No to this questionIs the reach capable of growing trees, e.g.
cottonwood, aspen and conifers? NoIs large or coarse debris a
necessary hydrologic controls? NoIs the site dominated by
stabilizing shrub species? Shrubs and HerbaceousHas the site had
the trees removed from the site? Are there trees growing within one
tree height of the stream channel?
Not applicableWe have talked about vegetation and water. Now we
will talk about the landscape and soils. Again, the stool needs all
three legs in the proper length to fully support the load. If one
leg is damaged, it can fail and cause a sudden letdown. Thus it
takes all three parts to maintain healthy, functioning, and
productive systems.
