Geology 230 Groundwater/ surface water interaction Tim Horner Geology Department, CSU Sacramento

1
Geology 230Groundwater/ surface water
interaction Tim HornerGeology Department, CSU
Sacramento

• Week 1 Stream classification
• Reading assignment
• 1) EPA Watershed Academy, 2005, Fundamentals of
  the Rosgen Stream Classification System 
  Accessed 8/29/05 at http//www.epa.gov/watertrain/
  stream_clas/index.htm.
•   
• 2) Montgomery, D. R., and Buffington, J. M.,
  1994, Channel-reach morphology in mountain
  drainage basins Geological Society of America
  Bulletin, v. 109, pp. 596-611.
• 3) Mial, A. D., 1977, Lithofacies Types and
  Vertical Profile Models in Braided River
  Deposits A Summary, in, Fluvial Sedimentology
  Memoir 5, Fluvial Facies Models, pp. 597-604.

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Methods used to characterize streams Miall-
A sedimentologists approach Rosgen- Based on
channel morphology Montgomery and Buffington-
More process based
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Mialls lithofacies designations
From Miall, 1977
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Mialls stream types- braided rivers
From Miall, 1977
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Mialls stream types- braided rivers Examples
are intended to show all of the variability in
braided streams.
Several are based on glacial outwash
High energy with limited sediment supply
proximal -------------------------distal
Debris flow
From Miall, 1977
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Rosgens classification system
From EPA Watershed Academy, 2005
Advantages Disadvantages

• Simple key, can be used by inexperienced field
  hands
• Looks mostly at form

• Simple key, can be used by inexperienced field
  hands
• May not represent scale accurately

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Rosgens classification system

• Three main parts
• Level I classification, which is based on the
  stream characteristics that result from relief,
  landform, and valley morphology
• Valley type, a primary determinant of stream
  form
• Level II classification, which provides more
  detailed morphological description of stream type
  from field measurements of channel form and bed
  composition.

From EPA Watershed Academy, 2005
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• Level I Stream Classification
• The Level I stream classification serves four
  primary functions
• Provide for the initial integration of basin
  characteristics, valley types, and landforms with
  stream system morphology.
• Provide a consistent initial framework for
  organizing river information and communicating
  the aspects of river morphology. Mapping of
  physiographic attributes at Level I can quickly
  determine location and approximate percentage of
  river types within a watershed and/or valley
  type.
• Assist in the setting of priorities for
  conducting more detailed assessments and/or
  companion inventories.
• Correlate similar general level inventories
  such as fisheries habitat, river boating
  categories, and riparian habitat with companion
  river inventories.
• The Level 1 Stream Classification produces a
  letter A - G

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Level I Stream Classification

• Is landscape scale
• Can be accomplished with topo maps or air photos

From EPA Watershed Academy, 2005
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Level 1 assessment Depends on basin-scale
factors
From EPA Watershed Academy, 2005
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From EPA Watershed Academy, 2005
High energy, high sediment load
multiple channels
anastomosing
stable channel, more entrenched, low relief

• Variables
• gradient
• width/depth ratio
• lateral confinement
• sinuosity

• entrenchment
• meander geometry
• erosion
• sinuosity

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Level 2 assessment Valley type
There are 11 Valley Types. Valley types may
correlate with Level 1 stream types
From EPA Watershed Academy, 2005
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Level 2 assessment Valley type
There are 11 Valley Types. Valley types may
correlate with Level 1 stream types
Type X, XI may include wetlands
From EPA Watershed Academy, 2005
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Part 3 Level II Stream Classification
From EPA Watershed Academy, 2005
Cross-sectional measurements Entrenchment
Ratio A computed index value which is used to
describe the degree of vertical containment of a
river channel (width of the flood prone area at
an elevation twice the maximum bankfull
depth/bankfull width). Width/depth Ratio An
index value which indicates the shape of the
channel cross-section (ratio of bankfull
width/mean bankfull depth). Dominant Channel
Materials A selected particle size index value,
the D50, representing the most prevalent of one
of six channel material types or size categories,
as determined from a channel material size
distribution analysis. Longitudinal Profile
measurements Slope Slope of the water surface
averaged for 20-30 channel widths. Bed Features
Secondary delineative criteria describing channel
configuration in terms of riffle/pools, rapids,
step/pools, cascades and convergence/divergence
features which are inferred from channel plan
form and gradient. Plan-form (pattern)
measurements Sinuosity Defined as stream
length/valley length or valley slope/channel
slope). Meander Width Ratio A secondary
delineative criteria defined as meander belt
width/bankfull width that describes the degree of
lateral channel containment, and is primarily
used in assisting aerial photo delineation of
stream types.
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Part 3 Level II Stream Classification
From EPA Watershed Academy, 2005
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Part 3 Level II Stream Classification
From EPA Watershed Academy, 2005
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Gathering field data for Level II Stream
Classification
Visual or physical indicators of the bankfull
stage The presence of a floodplain at the
elevation of incipient flooding. The elevation
associated with the top of the highest
depositional features (e.g., point bars, central
bars within the active channel). These
depositional features are especially good stage
indicators for channels in the presence of
terraces or adjacent colluvial slopes. A break
in slope of the banks and/or a change in the
particle size distribution, (since finer material
is associated with deposition by overflow, rather
than deposition of coarser material within the
active channel). Evidence of an inundation
feature such as small benches. Staining of
rocks. Exposed root hairs below an intact soil
layer indicating exposure to erosive flow.
Lichens and - for some stream types and locales
- certain riparian vegetation species
From EPA Watershed Academy, 2005
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Measuring bankfull stage in the field
From EPA Watershed Academy, 2005
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Estimating entrenchment ratio
From EPA Watershed Academy, 2005
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Estimating width/depth ratio
From EPA Watershed Academy, 2005
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Estimating sinuosity
From EPA Watershed Academy, 2005
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Estimating slope
From EPA Watershed Academy, 2005
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Estimating channel material (pebble counts)
From EPA Watershed Academy, 2005
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Summary Rosgens stream classification method
From EPA Watershed Academy, 2005
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Montgomery and Buffington, 1997
Looks at reach-level stream features 7 alluvial
channel types colluvial bedrock cascade step
pool plane bed pool riffle dune riffle
Montgomery and Buffington, 1997
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Montgomery and Buffington channel types
From Montgomery and Buffington, 1997
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Montgomery and Buffington channel types
From Montgomery and Buffington, 1997
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Montgomery and Buffington channel types
From Montgomery and Buffington, 1997
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Montgomery and Buffington channel type vs.
gradient
From Montgomery and Buffington, 1997
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Montgomery and Buffington channel type vs.
drainage area
From Montgomery and Buffington, 1997
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Montgomery and Buffington channel type vs.
roughness and grain size
From Montgomery and Buffington, 1997
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Montgomery and Buffington channel type vs.
roughness and grain size
From Montgomery and Buffington, 1997
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Montgomery and Buffington channel type transport
capacity
From Montgomery and Buffington, 1997
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Montgomery and Buffington channel response to
changes in sediment supply and discharge
From Montgomery and Buffington, 1997
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Other methods of stream characterization Strahle
r, order of streams