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GEOL 332 Lab 4Mad River River Bed

Name: _____________________________________________ Date: _______________

Team Name: ___________________________ Team Members: ________________________________

____________________________________________________________________________________

Our goal today is to characterize some fluvial sediments, at two different sites along the Mad River, and

within each site. We will form teams and describe sediments in a few locations. When taking notes of

our observations, we want to take the notes in the same order each time, as usual. We will form groups

of three or four.

We will learn:

How particle size

distributions are

controlled by

geomorphic

setting

How gravel

orientation may

be related to

geomorphic

setting

There will be two stops along

the Mad River. The first stop

will be at the Mad River

pump station park. We will

map the sediment particle

size distribution along a

cross-sectional transect

perpendicular to river flow.

We will prepare a plan view

map and a vertical cross

section. We will collect

Wolman Pebble Count

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Fig. 1. Process domains defined by (a) Schumm (1977) (as depicted by Kondolf, 1994) and (b) Montgomery (1999).


Particle size data at

stations based upon an

initial review of the

sedimentary /

geomorphic

environments present.

These data will be

entered into a

spreadsheet and

plotted in various ways.

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The second stop will be along a

tributary to the Mad River,

immediately upstream of its

confluence with the Mad River. We

will also prepare a plan view map,

vertical cross section, and particle

size data. We will supplement

these data with a sediment clast

imbrication analysis. The particle

size data will be plotted like for

stop 1. The clast imbrication data

will be plotted on a stereo net,

using poles to planes and plunge

axis plots. This may be done by

hand or with software.

Sedimentary Environments

Fluvial sedimentary environments

can be spatially related to different

fluvial geomorphic processes.

When interpreting fluvial

sediments and rocks, having a

knowledge about what particle size

distributions occur in different

geomorphic settings improves the

likelihood that one’s interpretation

is correct. To do this, we must

know a little about fluvial processes

and different geomorphic settings.

One way to approach this is to consider geomorphology, which implies that “form implies process.”

There are many uses for

channel classification systems (simplifying complex models for interpreting the complex continuum of

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Fig. 3. Schumm’s (1963a, 1977, 1981, 1985) classification of alluvial rivers.

Fig. 4. Schumm’s (1977, 1981, 1985) classification of channel pattern and response potential as modified by Church (2006).


processes and conditions

within a landscape by

identifying places that

function in a similar

manner, interpreting and

assessing entrainment,

transport, and

depositional conditions,

etc.). We will use some of

these classification

systems to help us

visualize the variation in

fluvial sedimentary

environments.

Process Domains:

Schumm (1977) divided rivers into sediment production, transfer, and deposition zones, providing a

process-based view of sediment movement through river networks over geologic time (Figure 1A).

Process domains are portions

of the river network

characterized by specific

suites of interrelated

disturbance processes,

channel morphologies, and

aquatic habitats, and at a

general level roughly correspond with source, transport, and response reaches in mountain basins

(Figure 1B; Montgomery, 1999).

Classification of rivers using process domains is a coarse filter (typically lumping several channel types),

but it identifies fundamental geomorphic units within the landscape that structure general river

behavior and associated aquatic habitats.

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Figure 5. Map and diagrammatic schematic views of a drainage basin to illustrate the concept of ‘coupling’ between a stream channel and adjacent hillside slopes. Near the upstream limit of the decoupled reach there will usually be a significant ‘partially coupled’ reach, where stream channels move against, and then away from adjacent hillslopes. On the left side of the diagram are schematic graphs of characteristic grain size distributions through the channel system. In each graph, the next upstream distribution is shown (dashed line) so the intervening modification by stream sorting processes may be directly appraised. On the right hand side of the diagram are graphs to illustrate the attenuation of sediment movement down the system. Attenuation is the consequence of increasing mobility of finer material farther downstream, tributary confluences with variations in runoff timing, and of diffusive processes associated with channel flow.


Channel Pattern: Most river classifications that have been

developed involve classification of channel pattern (i.e.,

planform geometry, such as straight, meandering, or

braided), which can be broadly divided into two approaches:

(1) quantitative relationships (which may be either empirical

or theoretical) and (2) conceptual frameworks.

Quantitative relationships – Lane (1957) and Leopold and

Wolman (1957) observed that for a given discharge, braided

channels occur on steeper slopes than meandering rivers

(Figure 2).

Conceptual frameworks – Schumm’s (1960, 1963, 1968,

1971a, b, 1977) work on sand- and gravel-bed rivers in the

Great Plains of the western U.S. emphasized that channel

pattern and stability are strongly influenced by the imposed

load of the river (size of sediment and mode of transport)

and the silt-clay content of the floodplain (providing

cohesion necessary for the development of river

meandering). Based on these observations, Schumm (1963,

1977, 1981, 1985) proposed a conceptual framework for

classifying alluvial rivers that related channel pattern and

stability to (1) the silt-clay content of the banks, (2) the

mode of sediment transport (suspended load, mixed load, bed load), (3) the ratio of bed load to total

load (a function of stream power, sediment size, and supply), and (4) the slope and width-to-depth ratio

of the channel (Figure 3). Schumm’s (1963a, 1977, 1981, 1985) classification has since been refined to

include a broader range of channel types (Mollard, 1973; Brice, 1982), including steeper morphologies

present in mountain rivers (Church, 1992, 2006; Figure 4).

Channel pattern classification approaches are typically descriptive (associating physical conditions with

channel morphology, but not explaining the underlying processes) or involve a mixture of descriptive

and process-based interpretations. A comprehensive presentation of different channel classification

systems is in Buffington and Montgomery (2013).

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Channel elements in high gradient channels (a) step-pool system; (b) pool-riffle-bar system.


Church (2002) presented a

figure that shows how sediment

size may vary in a drainage

basin, a conceptual approach

listed above (Figure 5). Church

(2002) also presents a figure

that shows how particle size

may vary in different

sedimentary settings (Figure 6).

Bunte and Abt (2001) present a

schematic longitudinal and

planform view of five stream

types at low flow. (A) Cascade

with nearly continuous highly

turbulent flow around large

particles; (B) Step-pool channel

with sequential highly turbulent

flow over steps and more

tranquil flows through

intervening pools; (C) Plane-bed

channel with an isolated boulder

protruding through otherwise

uniform flow; (D) Pool-riffle

channel with exposed bars,

highly turbulent flow over riffles,

and more tranquil flow through

pools; and (E) Dune-ripple

channel with dune-ripple

bedforms (Figure 7).

Finally, Rosgen (1994) relates stream form to slope, cross section, plan view, and particle size (Figure 8).

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Fig. 7. Schematic longitudinal (left) and planform (right) illustration of the five stream types at low flow: (A) Cascade with nearly continuous highly turbulent flow around large particles; (B) Step-pool channel with sequential highly turbulent flow over steps and more tranquil flows through intervening pools; (C) Plane-bed channel with an isolated boulder protruding through otherwise uniform flow; (D) Pool-riffle channel with exposed bars, highly turbulent flow over riffles, and more tranquil flow through pools; and (E) Dune-ripple channel with dune-ripple bedforms.


An illustration that attempts to

bring together the major

factors that control

entrainment, transport, and

deposition in a fluvial system is

presented in Figure 9. In the

Lane balance diagram, flow–

sediment interactions

determine the aggradational –

degradational balance of river

courses. (a) The river maintains

a balance, accommodating

adjustments to the

flow/sediment load. (b) Excess

flow over steep slopes, or

reduced sediment loads, tilts

the balance towards

degradation and incision

occurs. (c) Excess sediment

loads of a sufficiently coarse

nature, or reduced flows, tilt

the balance towards

aggradation and deposition

occurs. The arrows on (b) and (c)

indicate the way in which the channel adjusts its flow/sediment regime to maintain a balance.

Wolman Pebble Count

The composition of the streambed and banks are important facets of stream character, influencing

channel form and hydraulics, erosion rates, sediment supply, and other parameters. Observations tell us

that steep mountain streams with beds of boulders and cobbles act differently from low- gradient

streams with beds of sand or silt. You can document this difference by collecting representative samples

of the bed materials using a procedure called a pebble count. In this case, one would collect particle size

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Fig. 8. Rosgen’s stream classification. Longitudinal, cross-sectional and plan views of mayor stream types (top); Cross-sectional shape, bed-material size, and morphometric delineative criteria of the 41 major stream types (bottom).


data across the entire fluvial landscape within

the reach of river or stream, using the “zig-

zag” data collection pattern (Bevenger and

King, 1995). Alternately, one could analyze

different geomorphic settings within a reach of

a river or stream. In this case, one would limit

their station analyses to those specific

geomorphic settings. We will be analyzing

specific geomorphic settings at our first stop

and a hybrid approach at our second stop.

Regardless of which method one uses, for each data collection station, the following are the general

steps. “Averting your gaze,” pick up the first particle touched by the tip of your index finger at the toe of

your shoe/boot/wader. Measure the intermediate axis (neither the longest nor shortest of the three

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mutually perpendicular sides of each particle picked up;

Axis B; Figure 10). Measure embedded particles or those

too large to be moved in place. For these, measure the

smaller of the two exposed axes. Call out the

measurement. The note taker tallies it by size class and

repeats it back for confirmation. There are many

different size class schema. For this lab, use the size

classes presented in Table 1.

Clast Orientation

Clast imbrication is an indicator of modern current and

palaeocurrent direction. There are many aspects that are

important to consider and these are detailed in Bunte and Abt (2001).

For our data collection in this lab, we

will collect the strike and dip for a

number of clasts at stop 2 of our field

trip (Figure 11). For clasts that have

equal B- and C-axis measurements (a

“roller”), collect the data as trend

(compass orientation; the same as

strike) and plunge (angle below the

horizontal plane; Figure 12).

Many people use a small sheet of

rigid aluminum to help determine the orientation of the clasts that one is measuring. The instructor will

have small pieces of cardboard for those without a sheet of aluminum. Basically, hold the card

(aluminum or cardboard) with the flat dimensions of the card aligned with the A-B axis direction. Then

use one’s pocket transit to measure the strike and dip of the orientation of the card. Have one person

make observations, one person collect the data, and the third person locate the station on the map and

the cross section. Rotate these roles during the cross-section transect.

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Fig. 11. Strike and Dip. From Dr. M.H. Hill at Jacksonville State University here: http://www.jsu.edu/dept/geography/mhill/phylabtwo/lab4/dipf.html


Stop 1: Mad River at the pump

station park

Here we will conduct our first sediment

sampling transect. We will conduct a

single river flow perpendicular cross-

section transect along the river,

perpendicular to the flow. The cross-

section transect will extend from the

wetted edge, southward, across the

gravel bar, and up to the edge of the

vegetated floodplain. Take a look at the

cross-section transect and think about

the different sedimentary

environments along the cross-

section transect. Choose three pebble count stations. We will conduct a Wolman Pebble Count at

stations in each of these sedimentary environments. One person should make the observation and the

other two should take notes. Rotate these roles during the lab, at each of the three stations. Make sure

that everyone has a full set of these data observations in their own notebooks. This might involve

making electronic scans of your notebooks after the field trips is over (to save time).

Prepare a plan view and cross sectional view of your cross section transect. Distances will be based upon

your paces and the vertical changes in elevation will be estimated. Make sure that your group’s maps

and cross sections generally match. Label your stations on the map and the topographic cross section.

You will include these illustrations in your report.

Pebble count data will be entered into an electronic spreadsheet. Prepare two plots: (1) a volume

percent frequency distribution and (2) a cumulative percent distribution. Plot each sample location with

a different symbol.

Stop 2: Mad River upstream of the Blue Lake Bridge

Here we will conduct our second sediment sampling transect. We will conduct a single transect along

this tributary to the Mad River, Just upstream of the confluence. Each team will prepare a topographical

cross section, using a stadia rod and pocket transits. Each team will sample the particle size distribution

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Fig. 12. Orientation and Plunge. From: http://www4.ncsu.edu/~fodor/mea101.html


at evenly spaced stations across the river flow perpendicular cross-section transect. Finally, each team

will collect clast imbrication data for about 10 clasts in each sedimentary environment. We will set up

the cross section transects at one river mile position, and collect clast orientation data upstream of the

cross section transect.

Report

Meet with your group sometime after the field trip is over. Discuss your observations in the field, the

data, the results, and what you learned during and after the field trip. You might want to meet twice,

before you do your analyses and after you perform your analyses. If you work together, feel free to

share the same spreadsheet within your group (the data entry is time consuming). I would like each

student to prepare their own plots.

Prepare a report and submit electronically to [email protected] . This lab is due prior to class

two weeks from the day of the field trip. I will not accept hard copies of your report.

The filename needs to be in the correct format or you will miss out on some points!!! The name format

is in the syllabus.

The report should be in a standard format (e.g. introduction, methods, results, discussion, and

conclusion). I have placed a writing guide on the website. The report should include tables of your data,

your maps, and your cross sections. Each table, map, and cross section needs to have a figure caption.

References:

Bevenger, Gregory S.; King, Rudy M., 1995. A pebble count procedure for assessing watershed cumulative effects. Res. Pap. RM-RP-319. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 17 p.

Brice, J.C., 1982. Stream channel stability assessment. US Department of Transportation, Federal Highway Administration Report FHWA/RD-82/021, Washington, DC, 42 pp.

Buffington, J.M., Montgomery, D.R., 2013. Geomorphic classification of rivers. In: Schroder, J. (Editor in Chief), Wohl, E. (Ed.), Treatise on Geomorphology. Academic Press, San Diego, CA, vol. 9, Fluvial Geomorphology, p. 730–767.

Bunte, K. and Abt, S. R. 2001. Sampling surface and subsurface particle-size distributions in wadable gravel- and cobble-bed streams for analyses in sediment transport, hydraulics, and streambed monitoring. Gen. Tech. Rep. RMRS-GTR-74. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. 428 p.

Church, M., 1992. Channel morphology and typology. In: Carlow, P., Petts, G.E. (Eds.), The Rivers Handbook. Blackwell, Oxford, UK, pp. 126–143.

Church, M., 2002. Geomorphic thresholds in riverine landscapes. Freshwater Biology 47, p. 541–557.

Church, M., 2006. Bed material transport and the morphology of alluvial rivers. Annual Review of Earth and Planetary Sciences 34, p. 325–354.

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mailto:[email protected]


Kondolf, G.M., 1994. Geomorphic and environmental effects of instream gravel mining. Landscape and Urban Planning 28, p. 225–243.Lane, E. W., 1955. The importance of fluvial morphology in hydraulic engineering. Proceedings, American Society of Civil Engineers, v. 81, Paper 745, pp. 17.

Lane, E.W., 1957. A study of the shape of channels formed by natural streams flowing in erodible material. U.S. Army Engineer Division, Missouri River, Corps of Engineers, MRD Sediment Series no. 9, Omaha, NE, 106 pp.

Leopold, L.B., Wolman, M.G., 1957. River channel patterns: braided, meandering, and straight. U.S. Geological Survey Professional Paper 282-B, Washington, DC, p. 39–84.

Mollard, J.D., 1973. Air photo interpretation of fluvial features. Fluvial Processes and Sedimentation. National Research Council of Canada, Ottawa, ON, p. 341–380.

Montgomery, D.R., 1999. Process domains and the river continuum. Journal of the American Water Resources Association 35, p. 397–410.

Rosgen, D.L., 1994. A classification of natural rivers. Catena 21: 169-199.

Schumm, S.A., 1960. The shape of alluvial channels in relation to sediment type. U.S. Geological Survey Professional Paper 352-B, Washington, DC, pp. 17–30.

Schumm, S.A., 1963. A Tentative Classification of Alluvial River Channels. U.S. Geological Survey Circular 477, Washington, DC, 10 pp.

Schumm, S.A., 1968. Speculations concerning paleohydrologic controls of terrestrial sedimentation. Geological Society of America Bulletin 79, p. 1573–1588.

Schumm, S.A., 1971a. Fluvial geomorphology: channel adjustment and river metamorphosis. In: Shen, H.W. (Ed.), River Mechanics. H.W. Shen, Fort Collins, CO, p. 5-1–5-22.

Schumm, S.A., 1971b. Fluvial geomorphology: the historical perspective. In: Shen, H.W. (Ed.), River Mechanics. H.W. Shen, Fort Collins, CO, pp. 4-1–4-29. Schumm, S.A., 1977. The Fluvial System. Blackburn Press, Caldwell, NJ, 338 pp.

Schumm, S.A., 1981. Evolution and response of the fluvial system, sedimentological implications. In: Ethridge, F.G., Flores, R.M. (Eds.), Recent and Nonmarine Depositional Environments. SEPM (Society for Sedimentary Geology), Special Publication 31, Tulsa, OK, p. 19–29.

Schumm, S.A., 1985. Patterns of alluvial rivers. Annual Review of Earth and Planetary Sciences 13, p. 5–27.

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