Process for Assessing Proper Functioning
Condition
Hydrology Items
Lentic (wetland) and Lotic
(riparian) Areas
Hydrology
Soil, Landscape
The Hydrologic Cycle
Vegetation
Streamflow regime
 Precipitation
seasonality


Timing in relation to Et
Intensity, duration
 Streamflow regime
determines the
mechanical forces
available to erode,
transport and deposit
sediment.
Streamflow variability
Natural flow regime
 The natural flow regime is
 Ecologically relevant
responsible for structuring
and maintaining the
physical and biotic
integrity of aquatic and
riparian
p
ecosystems.
y
 Annual variations in the
magnitudes of high and
low flows characterize the
natural flow variability that
is important to maintaining
the ecological integrity of
the riparian and aquatic
ecosystems.
elements of stream
flow include:
1.
2
2.
3.
4.
5.
Magnitude
Frequency
Duration
Timing
Rate of change
1
Intermediate disturbance
hypothesis
 In absence of disturbance:
Superior competitors
will eliminate inferior
one and reduce
species richness
 Too frequent disturbance:
 Resident competitors
will be eliminated and
colonizing species will
dominate
 Maximum diversity is
maintained in systems
with intermediate levels of
disturbance

Stability
 The definition of natural stability is “the ability of
a stream, over time, in the present climate, to
transport the sediment and streamflow
produced by the watershed in such a manner
that the stream channel dimension, pattern, and
profile are maintained without either aggrading
or degrading.” Rosgen 1996.
Stability = Rigidity
maintaining dimension,
pattern, and profile
The potential of a stream and its associated
riparian-wetland area is characterized by the
interaction of vegetation, landform/soils, and
Rosgen 1996
hydrology
Regional and Local Relationships
Stream Types Across
the Landscape
 Develop or use
regional and localized
information on
geomorphic
characterization,,
hydrology, and
hydraulics.
Adapted from: “Federal Interagency Stream Corridor Restoration Working Group 1998”
2
HYDROLOGY CHECKLIST
ITEMS
 Floodplain
1) Floodplain above bankfull is inundated
in “relatively frequent” events
Purpose – determine whether frequent flood flows
are capable of spreading out on a low-lying area
adjacent to the stream and thus provide for:
 Beaver Dams
 Channel
Energy di
E
dissipation
i ti
Sediment deposition
 Periodic flooding of vegetation
 Periodic infiltration of floodwaters

Characteristics
Ch
t i ti
 Riparian Area
Widening
 Watershed
Influence

Floodplain
Definition: Floodplain
 Level area near a stream
 How much room
channel
does flood water
have to spread out
& reduce energy?
 Temporary
storage of water
and sediments
 Constructed by the
stream
 In the present climate
 Flooded during moderate
& high flow events
 Should not be confused
with terraces (abandoned
floodplains)
(adapted from Leopold
1994)
Item #1: Floodplain inundation
Item #1: Floodplain inundation
Bankfull Stage Indicators
Definition: Bankfull
 Gaging station data
 Deposition Features –
 Flow that just fills the
Floodplain/Point bars
channel
Terrace
Bankfull
 Changes in vegetation
 Topographic
p g p
break in
 Point where water just
begins to overflow onto
a floodplain
 1.5 yr return interval is
considered a reasonable
average
slope
 Change in size,
staining, or color of
substrate materials
 Change in nature and
amount of debris
deposits
Floodplain
Item #1: Floodplain inundation
Verry et al. 2000
Item #1: Floodplain inundation
3
Examples of visual indicators that water has
accessed the floodplain:
Examples of visual indicators
Channel shape within the valley bottom
Bankfull indicators
Yes
No
NA
Item #1: Floodplain inundation
Bear Cr OR 1977
Yes
No
Sediment or debris
deposition
 Vegetation laid
down by flow
 Healthy riparianwetland vegetation

NA
Bear Cr OR 1988
2) Where beaver dams are present, they
are active and stable
Purpose
 Document whether beaver
dams are present
 If so, are they being
maintained?
Visual indicators of
beaver activity or
inactivity:
 Dam
construction
material
 Dams
D
kkeyed
d
into
streambanks
 Breaches
If not maintained or captured by vegetation, breaching can
unleash tremendous energy
3) Sinuosity, width/depth ratio, and
gradient are in balance with the landscape
setting
Visual indicators that a stream is in
balance with its environment:

Purpose – is the stream
near the shape and size
expected for its setting?

Rosgen stream type
Aerial photos
 3 parts that must all be
‘yes’ for the answer to be
‘yes’
 sinuosity
 width/depth ratio
 gradient
Janes Meadow WY 1989
Janes Meadow WY 1997
4
Visual indicators of instability:



Bank cutting
on straight
stretches
between
meanders
( idth)
(width)
False banks
that keep
eroding away
Excess
deposition
Visual indicators of stability:


Overhanging banks
Stabilizing false banks
Belgo Cr BC
1996
Visual indicators of water/sediment
imbalance:

Evidence of too
much water, not
enough water, too
much sediment
sediment,
not enough
sediment
Trapping Cr BC
1996
Examples of visual indicators:

Evidence of too much water, not enough
water, too much sediment, not enough
sediment
Badger Cr
Badger Cr
5
4) Riparian-wetland area is widening
or has achieved potential extent
Purpose – document that a riparian-wetland area
is recovering or has recovered, which is
expressed by an increase in riparian-wetland
vegetation.
 Sediment capture
 Floodplain development
 Flood-water retention
 Increase of riparian-wetland vegetation
This question has 2 parts
Is the riparian area widening?
Has the riparian area achieved its potential
extent?
1.
2.
The reason for this separation is so a “yes” answer is always
applied for a positive attribute or process. For example, it is
widening or it has achieved its potential extent.


As the water table rises, riparian-wetland area can expand
outward
As a stream channel narrows, riparian-wetland area
expands toward the center of the channel
Visual indicators of riparian area
expansion:
As a stream channel narrows, riparian-wetland area
expands toward the center of the channel



Riparian-wetland
community types
expanding
Upland plants
dying or dead
Fresh sediment
being captured
Bear Creek OR
1977
Bear Creek OR
1984
5) Upland watershed is not
contributing to riparian degradation
Purpose – document
whether there has
been a change in the
water or sediment
being supplied, and
whether it is resulting
in degradation
Fowl Manna Grass (Glyceria
striata)
Riparian-Watershed Linkages
 Recognizing the linkages between
riparian health and watershed
conditions is key for effectively
managing riparian ecosystems in a
balanced, environmentally sound and
holistic manner.
6
Watershed/River Assessment
 Conduct a watershed/river assessment to
determine river potential, current state and
the nature, magnitude, direction, duration,
and consequences of change.






Pertains to whether uplands are contributing
to the degradation of a riparian-wetland
area; it does not pertain to the condition of
the uplands
Review land use history
Isolate the causes of instability
Collect and analyze field data including reference
reach data
Define sediment, hydraulic, and morphololgic
parameters
Limiting factor analysis
Quantify streamflow and sediment regimes
Is riparian-wetland degradation coming
from the uplands?
Characteristics of properly functioning
riparian areas in the Colorado Plateau
1. Natural surface flow variability
 Upland
conditions are not contributing
= “yes”
 Upland
U l d conditions
diti
are contributing
t ib ti =
“no”
2. Active erosional and depositional processes
3. Relatively shallow alluvial groundwater
These characteristics collectively support;
a)
A “yes” answer provides a
positive indicator of functionality.
b)
Riparian vegetation dominated by native
species representing a diversity of structural
and functional groups
Aquatic habitat diversity
Questions?
7