©2010 elsevier, inc. chapter 6 physiography of flowing water dodds & whiles

©2010 Elsevier, Inc.

Chapter 6

Physiography of Flowing Water

Dodds & Whiles


FIGURE 6.1

Salt Creek Falls, Oregon.


FIGURE 6.2

Discharge as a function of area for a large number of watersheds in the United States. Letters are the abbreviations for the states from which the data were obtained. (Data courtesy of the US Geological Survey).


FIGURE 6.3

The Strahler method of stream ordering on a dendritic stream network (A). Order increases only when two streams of equal order meet. Other types of drainage patterns include rectangular, which may be found in Karst systems (B), and parallel, which occur mainly in deeply eroded areas (C). (Modified from Strahler and Strahler, 1979).


FIGURE 6.4

Relationships between stream order, average lengths of each order (A), number of streams of each order (B), and total length of streams of each order (C) for several watersheds in the southwestern United States. On average, streams of lower order are shorter, but they can also be more numerous; individual watersheds can have a greater total length of low-order streams. (Data from Allan, 1995, and Leopold et al., 1964).


FIGURE 6.5

A weir used to measure discharge from water height, viewed from downstream. There is a depth sensor and a lateral pipe system to log water depth continuously in this particular weir. The depth sensor and data logger are housed in an enclosure behind the bison to the left.


FIGURE 6.6

Hydrographs from three river systems plotted on log scales. The Niobrara River in Nebraska is mostly spring fed and shows relatively little variation in discharge among (A) and within years (B; note only about a 10-fold difference in each year, whereas two or three orders of magnitude are covered in the remaining hydrographs). Kings Creek in Kansas is a small, intermittent, prairie stream, with alternating periods of wet and dry over the years (C). A typical year in Kings Creek includes both times of no flow and floods (D; note 0.001 5 0 discharge in C and D). A stream in a steep watershed (Slaty River on the west coast of New Zealand) that experiences frequent rainstorms exhibits approximately weekly floods (E). (Data from A and B courtesy of US Geological Survey; data from C and D courtesy of Konza Prairie Long-TermEcological Research project; and data from E courtesy of Barry Biggs and Maurice Duncan) .


FIGURE 6.7

Discharge of the lower Missouri River. Prior to the 1950s, discharge was more variable than after dams were installed (A). A typical year before regulation (B) reveals a period of very low discharge in the winter, a spring peak, and a gradual decrease after early summer. After regulation (C), discharge is about the same throughout much of the year, except in winter when it is allowed to decrease after barge traffic halts. (Data courtesy of the US Geological Survey).


FIGURE 6.8

A hypothetical hydrograph of a storm event with precipitation and runoff in a natural area (A) and hypothetical comparison of watershed responses before and after urbanization (B). (After Leopold, 1994).


FIGURE 6.9

Flood frequencies plotted as recurrence intervals as a function of discharge for all recurrence intervals more than 1 year for the Seneca Creek watershed in Maryland before and after urbanization (peak discharge data from the US Geologic Survey; computed as in Leopold, 1994).


FIGURE 6.10

Conceptual diagrams of stream geomorphology. (Top) The side view is a cross-sectional lengthwise view showing pool and riffle sequence. (Middle) The top view shows a meandering stream, the thalweg (line of maximum velocity), and zones of erosion and deposition (point bars). (Bottom) The water velocity contours (cross-sectional across the channel) show how the maximum velocity is outside of the bend and the lateral current direction. When the thalweg crosses the channel, the maximum velocity is in the center of the channel.


FIGURE 6.11

Cross-sectional diagram of a stream showing the riffle pool sequence, accumulation of fine sediments, and water flow through the shallow subsurface (hyporheic).


FIGURE 6.12

Relationship between drainage area and meander length. (Redrawn from Leopold et al., 1964).


FIGURE 6.13

(A) General features of a floodplain (from Strahler and Strahler, Elements of Physical Geology, Copyright ©1979, reprinted by permission of John Wiley and Sons, Inc.) and (B) a diagram of heterogeneity of a tropical floodplain (from Welcomme, 1979; reprinted by permission of Addison Wesley Longman Ltd.).


FIGURE 6.14

Changes in the Willamette River related to channelization from 1850 to 1995 (A, image courtesy of Ashkenas, Gregory, and Minor, Oregon State University) and (B) snag and tree removal (data from Sedell and Froggatt, 1984).


FIGURE 6.15

Movement of a pulse of chloride through a stream channel with considerable areas of slack flow (transient storage zones). In a perfect channel, the pulse would be square as it moves downstream. (After Webster and Ehrman, 1996).


FIGURE 6.16

Movement of particles as a function of particle size for maximum and minimum flows in the East Fork River. Note that larger particles move more readily at greater discharge rates. (Reprinted by permissionof Harvard University Press from Leopold, 1994, © 1994 by the President and Fellows of Harvard College) .


FIGURE 6.17

Transport and erosion of particles as a function of water velocity. Note that the lines delineating transitions between erosion, transport, and sedimentation represent fuzzy rather than abrupt transitions. (After Allan, 1995 and Morisawa, 1968).


FIGURE 6.18

Distribution of particles with depth in the Missouri River expressed as total particle concentration (A) and as percentage concentration of bottom sediments for different sized particles (B). (Data plotted fromWilber, 1983).


FIGURE 6.19

Hill top, or mountain top removal mining for coal. (Image courtesy of Ohio Valley Environmental Coalition, Vivian Stockman).


FIGURE 6.20

The Grand Canyon at Hance Rapids. Note the stream entering from the left deposits materials that cause a pool behind the confluence, and a steep elevation drop immediately downstream leading to the rapids. Also note the river downcutting through sediment layers. (Photograph courtesy of the US Geological Survey, by L. Leopold).


FIGURE 6.21

Hierarchical representation of the geomorphological changes in stream channels (A) and related biotic processes (B). (After Alan, 1995; Frissell et al., 1986; Mitsch and Gosselink, 1993).

©2010 elsevier, inc. chapter 6 physiography of flowing water dodds & whiles

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