A Comparison of Two Third-Order Streams
Sarah Kirschensteiner
GEO 306: Dr. Schaetzl
December 6, 1996
Introduction
Streams can be classified using Strahler's stream-ordering system. A first-order stream
has no tributaries, a second-order stream has first-order tributaries, and a third-order
stream has first- and second-order tributaries. Figure 1 displays this concept.
The goal of this project was to find two third-order streams in two similar environments
for the purpose of finding out how one factor affects the system. The slope and soil type
were held constant, while the climate varied between the two areas. This project could
help a student of geomorphology to better understand the affects of climate on stream
length.
Study Area
The first step was to search for two areas that fit the description of the study. The
National Atlas of the United States of America contains sections about soils and slope
around the United States. After analyzing this information, the areas of northwestern
Missouri and northwestern Kansas were chosen. Both places are characterized by irregular
plains: 50 to 80 percent of the land is gently sloping, 50 to 75 percent of the gentle
slope is on upland, and the local relief ranges from 30 to 90 meters (100 to 300 feet)
(USGS 62-63). The soils in both of the sections are basically mollisols, which are nearly
black with an organic-rich surface horizon and a high base supply. The difference in these
two selected areas are their climates. The section in Missouri is typically humid,
averaging 81 to 102 centimeters (32 to 40 inches) of precipitation each year, while the
section in Kansas is dry with a mean annual precipitation of 41 to 61 centimeters (16 to
24 inches) (USGS 86-87, 97). These differences could definitely change the look of the
river systems.
Next, the actual third-order streams to use in this particular study needed to be found, staying within the soil and slope boundaries determined above. The stream systems chosen were the tributaries to Lost Creek in Jackson Township, Gentry County, Missouri and South Fork Solomon River in Sheridan and Graham Counties, Kansas. These can be found on the following 7.5 minute quadrangle topographic maps: Ford City, Missouri; Hoxie, Tasco, Studley, Lucerne, Morland, Morland NE, Penokee, Hill City NW, Hill City S, Bogue, and Bogue NW, Kansas. The beginning and ending locations of the chosen streams are as follows:
Missouri:
beginning locations(1)
:
S 1/2 section 11 T.61N, R.32W 5th Principal Meridian (2 stream origins)
NE 1/4 section 15 T.61N, R.32W 5th Principal Meridian
SE 1/4 section 10 T.61N, R.32W 5th Principal Meridian
ending point(2)
:
NW 1/4 section 24 T.61N, R.32W 5th Principal Meridian
Kansas:
beginning locations:
NW 1/4 section 22 T.8S, R.28W 6th Principal Meridian
W 1/2 section 6 T.9S, R.28W 6th Principal Meridian
NE 1/4 section 21 T.9S, R.21W 6th Principal Meridian
NE 1/4 section 20 T.9S, R.21W 6th Principal Meridian
ending point:
SW 1/4 section 14 T.8S, R.21W 6th Principal Meridian
Photocopies of the maps for these streams are attached. The Kansas specimen is only a
representation of the whole third-order stream system due to its extreme length. For ease
of viewing, the streams have been outlined in red. Also included are illustrations of the
streams with all of their tributaries in Figure 2. They show the basic organization of the
two systems, but are not drawn to scale and are not accurate in all of their meanders.
Figure 2. Two model stream systems. Arrows point in the direction of
stream flow. Drawings are not to scale or geographically correct. A. South Fork Solomon
River and tributaries, Kansas. B. Tributaries to Lost Creek, Missouri.
Methods
After finding and ordering the total extent of the two third-order streams, they could
then be measured. This process was done by walking a string along the entire course of the
stream system from the beginning of the tributaries to the conjunction of the two
second-order streams. Where ever a stream connected to another or ran off of the map edge,
the string was marked with a pen. The process was then resumed from this mark for the next
segment. Lakes were not measured unless they fell in the middle of a stream. In these
situations, the shortest distance was measured from the point where the stream dropped off
to the point where it resumed its regular course. Only perennial streams were considered
for this study because they contain water all year long. Many ephemeral streams were
encountered, but since they do not always hold water, they do not exert as much influence
upon stream length. Water remains in them only as long as it takes to drain all of it
away. It is a case similar to runoff after rain. Therefore, as was stated before, only
perennial streams were examined. The starting and ending elevations of the streams were
also recorded.
Once all of the measurements were complete, the strings were measured and converted
into actual stream lengths. The scale of all of the maps was 1:24,000. With the above
information and the knowledge that one kilometer equals 100,000 centimeters, the real
world lengths could be determined by using the following formula:
Actual length = n cm x 24,000 x 1 km/100,000 cm, where n
is the string length
Results
The string sample for Missouri was 37.1 centimeters (14.5 inches) and the one for Kansas
was 868.1 centimeters (338.6 inches). Using the above formula, the following calculations
could be made:
Missouri:
37.1 cm x 24,000 = 890,400 cm in the real world
890,400 cm x 1 km/100,000 cm = 8.904 km (5.53 miles)
Kansas:
868.1 cm x 24,000 = 20,834,400 cm in the real world
20,834,400 cm x 1 km/100,000 cm = 208.344 km (129.41 miles)
The highest elevation of MissouriÕs system was 324 to 328 meters (1063 to 1076 feet) above sea level and the lowest was 296 to 300 meters (971 to 984 feet). The relative relief between starting and ending points was 32 meters (105 feet). The highest elevation of KansasÕ system was 817 to 820 meters (2680 to 2690 feet) and the lowest was 600 to 603 meters (1970 to 1980 feet). The relative relief between starting and ending points was 220 meters (720 feet).
All of the above data illustrates the idea that a dry climate will make streams longer
than a humid one would. Because there is more water in a humid environment, more runoff
occurs in drainage systems, and streams elaborate more. The Missouri situation consists of
short tributaries (small enough not to be named on the map) that can quickly take away
water that runs off of the land. A stream system located in this area of Missouri that is
similar in length to the Kansas example would have many more tributaries and higher-order
streams. The climate of western Kansas affects its stream systems by starving them of
water, a situation that creates very long streams with some tributaries that do not even
contain water all year around. As can be seen in Figure 2, it takes twelve first-order
streams to support two second-order streams in northwestern Kansas (bifurcation ratio =
6), whereas northwestern Missouri only needs four (bifurcation ratio = 2). A higher ratio
means that a stream needs more water input to maintain itself due to external factors that
affect it, in this case a dry climate. With these conclusions, this exercise has proven to
be successful in illustrating the difference climate can make upon two similar stream
systems. Dry environments elongate streams, and humid ones shorten them.
Bibliography
Kansas: Index to Topographic and Other Map Coverage. Reston, VA: United States Geological Survey, 1993.
Missouri: Index to Topographic and Other Map Coverage. Reston, VA: United States Geological Survey, 1994.
The National Atlas of the United States of America. Washington, D.C.: United
States Geological Survey, 1970.
Map Bibliography
Bogue, Kansas Quadrangle: 7.5 Minute Series (Topographic). Reston, VA: United States Geological Survey, 1979.
Bogue NW, Kansas Quadrangle: 7.5 Minute Series (Topographic). Reston, VA: United States Geological Survey, 1979.
Ford City, Missouri Quadrangle: 7.5 Minute Series (Topographic). Reston, VA: United States Geological Survey, 1985.
Hill City NW, Kansas Quadrangle: 7.5 Minute Series (Topographic). Reston, VA: United States Geological Survey, 1979.
Hill City S, Kansas Quadrangle: 7.5 Minute Series (Topographic). Reston, VA: United States Geological Survey, 1979.
Hoxie, Kansas Quadrangle: 7.5 Minute Series (Topographic). Reston, VA: United States Geological Survey, 1979.
Lucerne, Kansas Quadrangle: 7.5 Minute Series (Topographic). Reston, VA: United States Geological Survey, 1979.
Morland, Kansas Quadrangle: 7.5 Minute Series (Topographic). Reston, VA: United States Geological Survey, 1979.
Morland NE, Kansas Quadrangle: 7.5 Minute Series (Topographic). Reston, VA: United States Geological Survey, 1979.
Penokee, Kansas Quadrangle: 7.5 Minute Series (Topographic). Reston, VA: United States Geological Survey, 1979.
Studley, Kansas Quadrangle: 7.5 Minute Series (Topographic). Reston, VA: United States Geological Survey, 1979.
Tasco, Kansas Quadrangle: 7.5 Minute Series (Topographic). Reston, VA: United
States Geological Survey, 1979.
1. a The locations given for the beginning of the streams are the origins of the four first-order streams that come together to initially create the two second-order streams that produce the final third-order stream. The other first-order streams are not listed.
2. b The ending point of the system is the conjunction of the two second-order streams.