Transcript Stream Development and Longitudinal Stream Profiles

STREAM DEVELOPMENT AND
LONGITUDINAL STREAM
PROFILES
OBJECTIVE
 Look
at factors that affect stream
development
 Determine how streams vary by region
and difference in factors
 Ultimately be able to compare stream
profiles and determine anomalous
segments in profile
OUTLINE
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Longitudinal profiles and what controls stream
development

Profiles by region

Methods of obtaining stream profiles

Comparing stream profiles
LONGITUDINAL STREAM PROFILES

Shows distance vs. elevation of a stream
LONGITUDINAL STREAM PROFILES
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Changes on tectonic conditions, climate, or geology cause
changes in profile (Cherkauer, 1972).
The main factors that affect its slope are discharge,
drainage area, and size of material in the stream bed
(Hack, 1957).
Typical profile is concave-up
SUSQUEHANNA RIVER

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Convex profile
Little uplift
Changes in base
level and geology
play a more
important role
than uplift.
Carlston (1969)
found 8 streams
draining to
Atlantic to be
convex
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PROFILES IN MARYLAND AND VIRGINIA
Shorter streams that
help show variation in
geology
 Schist & sandstone
slopes decrease more
gradually compared to
shale or less resistant
units (Hack, 1957)
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TEXAS PROFILES
Most profiles in TX
have a long and
concave profile
 Some exceptions are
nearly linear
(slightly concave)Rio Jemez and
Matthole River.
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Constant incision
rate
 Not very tectonically
active

Tinkler, K.J., 1998
PROFILE SEGMENTS
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Not all profiles follow one pattern
Streams can be made up of segments based on differences in
slope and shape
ARIZONA STREAMS-SEGMENTED
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Steep upstream (concave)

Due to greater rate of change
of particle size and drainage
area, and higher width to
depth ratio of stream
Straight line downstream
 Ephemeral streams- exists
only after ppt (Cherkauer,
1972)
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GLACIAL PROFILES
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Wide and low gradient floors.
Profiles characterized by steps shortly after tributary joins
main glacier (MacGragor et al, 2000)
MAKING STREAM PROFILES
Plot of distance on x-axis vs. elevation above sea
level on y-axis
 Can infer from topographic maps (Hack, 1957) or
DEMs (Snyder et al, 2000)
 Survey in the field
 Once full profile is acquired, it can be broken up
into many segments based on shape
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STREAM-GRADIENT INDEX
Relates the slope of a stream to its length (Hack,
1973)
 Allows you to compare different streams
 Can determine small knickzones/irregularities
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SL= stream-gradient index
 ∆H= Change in elevation
 L= length of the Stream
 ∆L- Length of the specific reach of stream
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STREAM GRADIENT
Hack, 1957
STREAM GRADIENT
Hack (1957) developed this formula based on
profiles in humid regions on the East Coast
 Still useful because easy to calculate
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CONCLUSION
Changes on tectonic conditions, climate, or
geology cause changes in profile
 Different regions show different profiles
 A single stream can have many segments
 Stream-gradient index is a useful calculation to
compare profiles
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REFERENCES CITED
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Anderson, J.K., Wondzell, S.M., Gooseff, M.N., Haggerty, R., 2005, Patterns in stream longitudinal profiles and
implications for hyporheic exchange flow at the H.J. Andrews Experimental Forest, Oregon, USA: Hydrological
Processes, v. 19, p. 2931-2949.
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Carlston, C.W., 1969, Longitudinal slope characteristics of rivers of the midcontinent and the Atlantic east gulf slopes:
International Association of Scientific Hydrology Bulletin, v. 14, no. 4, p. 21-31.
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Cherkauer, D.S., 1972, Longitudinal profiles of ephemeral streams in southeastern Arizona: GSA Bulletin, v. 83, p.
353-366.
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Goldrick, G., Bishop, P., 2007, Regional analysis of bedrock stream long profiles: evaluation of Hack’s SL form, and
formulation and assessment of an alternative (the DS form): Earth Surface Processes and Landforms, v. 32, p. 649-671,
doi 10.1002/esp.1413.
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Hack, J.T., 1957, Studies of Longitudinal Stream Profiles in Virginia and Maryland: U.S. Geological Survey
Professional Paper 294-B, p. 42-97.
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Hack, J.T., 1973, Stream-profile analysis and stream-gradient index: Journal Research U.S. Geological Survey, v. 1, no.
4, p. 421-429.
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Larue, J.P., 2011, Longitudinal Profiles and Knickzones: the Example of the Rivers of the Cher in the Northern French
Massif Central: The Geologists’ Association, v. 122, p. 125-142.
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MacGregor K.R., Anderson, R.S., Anderson, S.P., Waddington, E.D., 2000, Numerical simulations of glacial-valley
longitudinal profile evolution, v. 28, no. 11, p. 1031-1034.
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Pazzaglia, F.J., Gardner, T.W., Merrits, D.J., 1998, Bedrock Fluvial Incision and Longitudinal Profile Development
Over Geologic Time Scales Determined by Fluvial Terraces: Rivers Over Rock: Fluvial Processes in Bedrock Channels,
p. 207-235.
Rosgen, D.L., 1994, A classification of natural rivers: Catena, v. 22, p. 169-199.
Snyder, N.P., Whipple, K.X., Tucker, G.E., Merritts, D.J., 2000, Landscape response to tectonic forcing: Digital
elevation model analysis of stream profiles in the Mendocino triple junction region, northern California: GSA Bulletin,
v. 112, no. 8, p. 1250-1263.
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Woodside, J., Peterson, E. W., and Dogwiler, T., in review, Longitudinal profile and sediment mobility as geomorphic
indicators within a fluviokarst stream system: Journal of Cave and Karst Studies.
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Zimmerman, A.E., Church, M., Hassan, M.A., 2008, Identification of Steps and Pools from Stream Longitudinal Profile
Data: Geomorphology, v. 102, p. 395-405.