A geomorphic history based on topographic evidence

The Elkhorn River-Platte River drainage divide area located in Stanton, Cuming, Colfax, and Dodge Counties, Nebraska is primarily drained by south-southeast and east oriented Maple Creek, southeast-oriented Pebble Creek, and east-oriented Rawhide Creek drainage systems, all of which flow to the south-southeast oriented Elkhorn River. Landform evidence is interpreted to have formed during an immense south-southeast oriented flood, which was complicated by a massive east-oriented flood moving along the present day Platte River alignment. South-southeast-oriented flood flow to what had been actively eroding Pebble Creek and Maple Creek valley systems was captured by Elkhorn River valley headward erosion. Flood waters on north ends of beheaded flood flow routes reversed flow direction to erode north-oriented Elkhorn River tributary valleys. East-oriented flood flow in the Platte River valley to south, while occurring at about the same time, appears to have come from the west, while flood flow responsible for most Elkhorn River-Platte River drainage divide area landform formation appears to have come from the northwest and north.

Preface:

• The purpose of this essay is to use topographic map interpretation methods to explore Elkhorn River-Platte River drainage divide area landform origins in Stanton, Cuming, Colfax, and Dodge Counties, Nebraska, USA. Map interpretation methods can be used to unravel many geomorphic events leading up to formation of present-day drainage routes and development of other landform features. While each detailed topographic map feature provides detailed evidence to be explained, the solution must be consistent with explanations for adjacent area map evidence as well as solutions to big picture map evidence puzzles. I invite readers to improve upon my solutions and/or to propose alternate solutions that better explain evidence and are also consistent with adjacent map area and big picture evidence. Readers may do so either by making comments here or by writing and publishing their own essays and then by leaving a link to those essays in a comment here.

• This essay is also exploring a new geomorphology paradigm in which erosional landforms are interpreted as evidence left by immense glacial melt water floods. Implied in that interpretation is the immense floods were derived from a thick North American ice sheet that created a deep “hole” in the North American continent and also melted fast. The previously unexplored paradigm being tested in this and other Missouri River drainage basin landform origins research project essays is a thick North American ice sheet, comparable in thickness to the Antarctic ice sheet, occupied the North American region usually recognized to have been glaciated, and through its weight and erosive actions created a deep North American “hole”. The southwestern rim of that deep “hole” is today preserved in the high Rocky Mountains. The ice sheet through its weight and deep erosion (and perhaps deposition along major south-oriented melt water flow routes) caused significant crustal warping and tectonic change, through its action of melting fast produced immense floods that flowed across the continent, and through its action of melting fast systematically opened up space in the ice sheet created “hole” so headward erosion of newly developed north-oriented drainage systems captured immense south-oriented melt water floods and diverted immense melt water floods north into space the ice sheet had once occupied.

• If this previously unexplored paradigm is correct the geographic region explored by this essay should contain evidence of immense floods that were captured by headward erosion of new valley systems so as to cause the floods to flow in a different direction. Ability of this previously unexplored paradigm to explain Elkhorn River-Platte River drainage divide area landform origins evidence in Stanton, Cuming, Colfax, and Dodge Counties, Nebraska will be regarded as evidence supporting the “thick ice sheet that melted fast” paradigm. This essay is included in the Missouri River drainage basin landform origins research project essay collection.

Elkhorn River-Platte River drainage divide area location map

Figure 1: Elkhorn River-Platte River drainage divide area location map (select and click on maps to enlarge). National Geographic Society map digitally presented using National Geographic Society TOPO software. 

Figure 1 provides a location map for the Elkhorn River-Platte River drainage divide area in Stanton, Cuming, Colfax, and Dodge Counties, Nebraska. Most of the figure 1 map area is located in eastern Nebraska, The northeast corner area is in the state of Iowa and the southeast tip of South Dakota is located northwest of Sioux City, Iowa. The south-southeast oriented Missouri River forms the Nebraska-Iowa border. The Elkhorn River originates near Bassett (located near the figure 1 north edge, west of center) and flows through Stuart, Atkinson, O’Neill, Ewing, Neligh, Oakdale, Tilden, Norfolk, Stanton, Pilger, Wisner, West Point, Scribner, Hooper, and Arlington before joining the Platte River west of Omaha, Nebraska. The Platte River flows from North Platte (near the figure 1 west edge) to Lexington, Kearney, Grand Island, Columbus, and Fremont before turning to flow south and east to join the south-southeast oriented Missouri River south of Omaha. The Elkhorn River-Platte River drainage divide illustrated and discussed here is located east of (or downstream from) Norfolk and Columbus and northwest and west of (or upstream from the Elkhorn River-Platte River confluence area). Figure 1 does not provide enough detail to show most drainage routes in the drainage divide area of concern, although two south-southeast branches of an east-oriented Elkhorn River tributary area are shown. That Elkhorn River tributary is Maple Creek and the two south-southeast oriented branches are the East Fork and West Fork of Maple Creek. Maple Creek is one of several streams west of the Elkhorn River and north of the Platte River to have long southeast or south-southeast oriented headwaters, and which near the Platte River valley turn to flow parallel to the Platte River valley, rather than flow directly to the Platte River valley. These east-oriented streams flowing parallel to the Platte River provide evidence of an east oriented flood. These multiple southeast and south-southeast oriented streams provide evidence of an immense southeast-oriented flood formed anastomosing channel complex, which once flowed across the figure 1 map area. Headward erosion of the Elkhorn River beheaded south-southeast oriented flood flow to what were then the actively eroding south-southeast oriented East Fork and West Fork Maple Creek and also to other south-southeast valleys west of the drainage divide area illustrated and discussed in this essay. In other words, drainage divide evidence is interpreted to suggest large south-southeast oriented floods flowed across the region to join massive east-oriented floods. Evidence to support this interpretation is illustrated and discussed in the  figures below. This essay begins by looking at evidence in Platte River valley area.

Elkhorn River-Platte River drainage divide area detailed location map

Figure 2: Elkhorn River-Platte River drainage divide area detailed location map. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 2 provides a slightly more detailed location map for the Elkhorn River-Platte River drainage divide area in Stanton, Cuming, Colfax, and Dodge Counties. Madison, Stanton, Cuming, Platte, Colfax, Dodge, Washington, Polk, Butler, Saunders, and Douglas are Nebraska county names and the county boundaries are shown. The Missouri River flows in a south-southeast direction near the figure 2 east edge. East of the Missouri River is the state of Iowa. Nebraska is west of Missouri River. Omaha, Nebraska is the city located in the figure 2 southeast corner. The Platte River flows in a northeast direction from the figure 2 southwest corner to near Columbus and then flows in an east and east-northeast direction to near Fremont in southeast Dodge County. At Fremont the Platte River turns to flow in a south-southeast direction to the figure 2 south edge. South of figure 2 the Platte River flows south and then east and joins the Missouri River south of Omaha. The Elkhorn River flows in an east direction in northern Madison County to Norfolk and then southeast to Stanton in Stanton County. From Stanton the Elkhorn River flows in a northeast direction to Pilger and in Cuming County the Elkhorn River turns to flow in a southeast and south direction into northeast Dodge County. From northeast Dodge County the Elkhorn River flows in a southeast and south-southeast direction to join the Platte River near the figure 2 south edge. Few Platte River tributaries from the north are shown in the Stanton, Cuming, Colfax, and Dodge County area, although several south-southeast streams appear to be flowing toward the Platte River. Most of these streams, when they get near the Platte River, turn to flow east parallel to the Platte River and eventually join the south-southeast oriented Elkhorn River. Of particular interest in this essay are the south-southeast oriented Dry Creek and East Fork and West Fork of Maple Creek, which join in southeast Colfax County and then flow as Maple Creek in a northeast and east direction across Dodge County to join the Elkhorn River. Also of interest is Pebble Creek, which flows parallel to the Elkhorn River in Cuming County and then joins the Elkhorn River in northern Dodge County. Rawhide Creek originates in southern Colfax County and flows south of Maple Creek and parallel to the Platte River across southern Dodge to join the Elkhorn River in southeast Dodge County. The change in drainage orientation from south-southeast oriented streams to east-oriented streams in southern Colfax and Dodge Counties is interpreted to be evidence of a massive south-southeast oriented flood coming from north and northwest of the figure 2 map area which flowed to a larger (or at least more concentrated) east-oriented flood moving across southern Colfax and Dodge Counties.

Platte River-Elkhorn River drainage divide area southeast of Fremont

Figure 3: Platte River-Elkhorn River drainage divide area southeast of Fremont. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 3 illustrates the Platte River-Elkhorn River drainage divide area southeast of Fremont. Fremont is the city located in the figure 3 northwest corner. The Platte River flows in a southeast direction from just south of Fremont in the figure 3 northwest corner to the figure 3 south center edge area. Arlington is the smaller city located along the figure 3 north center edge. The Elkhorn River flows in a south-southeast direction from the figure 3 north center edge near Arlington to the figure 3 south edge. The south-southeast oriented Platte River and Elkhorn River eventually join south of the figure 3 map area. The city located east of the Elkhorn River near the figure 3 south edge is Elkhorn while Waterloo is located just west of Elkhorn River. Kings Lake is the community north of Waterloo and Valley is the town northwest of Waterloo. Note Rawhide Creek, which flows across Fremont and then flows in a southeast direction to join the Elkhorn River north of Kings Lake. The present day Rawhide Creek channel is not the original channel and sections of the old channel are shown. Figures 4 and 7 below illustrate how west of Fremont Rawhide Creek flows parallel to the Platte River along the north edge of the large east-oriented Platte River valley. Note how the entire Platte River-Elkhorn River drainage divide has been eroded to what appears to be the same level as the Platte River and Elkhorn River valley floors. Also note south of the old Rawhide Creek channel the presence of an unnamed southeast-oriented Elkhorn River tributary (named Big Slough on more detailed maps), which originates in the figure 3 map area. The figure 3 evidence is interpreted to suggest the Platte River-Elkhorn River drainage divide area was eroded by southeast-oriented flood water moving to the south-southeast oriented Elkhorn River valley (or channel), while a slightly deeper southeast-oriented Platte River channel erode headward further to the southwest. This evidence suggests the Elkhorn River valley was probably eroded first, although shortly thereafter (and while large volumes of south-southeast oriented flood water was still moving in the Elkhorn River valley) large volumes of flood water moved east and southeast in the Platte River valley and flood waters from the two different valley systems came together and flowed roughly parallel to each other while eroding separate, but adjacent channels. Evidence supporting this interpretation is seen in figures below.

Maple Creek-Platte River drainage divide area northwest of Fremont

Figure 4: Maple Creek-Platte River drainage divide area northwest of Fremont. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 4 illustrates the Maple Creek-Platte River drainage divide area northwest of Fremont and of the figure 3 map area. Fremont is located in the figure 4 southeast corner. North Bend is the town located in the figure 4 southwest quadrant. Nickerson is the small town located north of Fremont in the figure 4 east center edge area. The Platte River flows in an east direction near the figure 4 south edge. The south-southeast oriented Elkhorn River is located near the north half of the figure 4 east edge area. Maple Creek is the east oriented stream flowing across the figure 4 north half and joining the Elkhorn River just north of Nickerson. Rawhide Creek is the east and northeast oriented stream in the figure 4 west center area and flows southeast to Fremont in the figure 4 southeast quadrant. Note how Rawhide Creek in the figure 4 center area is flowing along the north edge of the large east-oriented Platte River valley, while the Platte River channel is located along the valley’s south edge. Webster is the small town in the figure 4 northwest corner and Silver Creek is the stream flowing through Webster. North of figure 4 Silver Creek flows east-northeast, southeast, and north to reach the south-southeast oriented Elkhorn River (see figure 5 below). The figure 4 evidence, with the exception of the Elkhorn River, suggests the presence of multiple east-oriented channels, which could have originated as components of an east-oriented anastomosing channel complex. Other than the Elkhorn River valley there is no obvious figure 4 evidence suggesting a large south-southeast oriented flood flowed into the region. Instead there is figure 4 evidence suggesting large volumes of water once moved in an east direction across the figure 4 map area to reach the south-southeast-oriented Elkhorn River valley. This evidence suggests the Elkhorn River valley either was present first or was eroded headward to capture the east-oriented flood flow. The source of the east-oriented flood flow was west of the figure 4 map area, probably somewhere upstream in the Platte River drainage basin, which has its headwaters in the Wyoming and Colorado Rocky Mountains. This essay will not be able to determine where the east-oriented flood flow came from, but does provide evidence that large volumes of east-oriented flood flow did move into eastern Nebraska.

Pebble Creek Creek-Silver Creek drainage divide area

Figure 5: Pebble Creek Creek-Silver Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 5 illustrates the Pebble Creek-Silver Creek drainage divide north and slightly west of the figure 4 map area and includes overlap areas with figure 4. The south-southeast oriented Elkhorn River is located in the figure 5 northeast corner. Crowell is the small town located in the figure 5 northeast corner. The south-southeast oriented stream located along the figure 5 west edge area is the East Branch of Maple Creek. Remember, south of the figure 5 map area Maple Creek turns to flow east as seen in figure 4 above. Note the location of the small town of Webster on Silver Creek in the figure 5 southeast quadrant. Silver Creek originates as a southeast oriented stream and east of Webster turns to flow northeast before turning to flow southeast to the figure 5 east edge. East of figure 5 Silver Creek turns to flow in north-northwest direction back into the figure 5 map area and then turns to flow to join southeast oriented Pebble Creek just east of the figure 5 map area. Pebble Creek flows in southeast and east direction from the figure 5 north edge (east half) to the figure 5 east center edge. A southeast and east oriented Pebble Creek tributary flows through the towns of Dodge and Snyder in the figure 5 north half and joins Pebble Creek just east of Snyder. That unnamed Pebble Creek tributary has a significant southeast and northeast oriented tributary that joins it just west of Snyder. South of Silver Creek in the figure 5 south center area is southeast-oriented Crystal Creek, which south of the figure 5 map area flows to join east-oriented Maple Creek. Note how northeast-oriented Silver Creek segments and northeast-oriented Pebble Creek tributary segments all have southeast-oriented headwaters and/or tributaries. Unlike the figure 4 map area to the south the figure 5 map area shows evidence the northeast-oriented valleys eroded headward across multiple southeast or south-southeast oriented flood flow channels to capture south-southeast oriented flood flow and to divert flood waters to what must have been the newly eroded and deeper south-southeast-oriented Elkhorn River valley. In other words, the figure 5 map area was eroded by southeast and/or south-southeast oriented flood flow, which moved across the entire figure 5 map area initially on a topographic surface at least as high as the highest figure 5 elevations today. Headward erosion of the Silver Creek valley then captured the flood waters which had been moving to the east-oriented Maple Creek and/or Platte River valleys. Next headward erosion of the Pebble valley system beheaded flood flow to the newly eroded Silver Creek valley. Figure 6 below provides a detailed map of the west end of the drainage divide between the northeast-oriented Pebble Creek tributary and the Silver Creek valley.

Detailed map of Pebble Creek tributary-Silver Creek drainage divide area

Figure 6: Detailed map of Pebble Creek tributary-Silver Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 6 provides a detailed map of the west end of the drainage divide between a southeast and northeast oriented Pebble Creek tributary (southwest of Snyder) and the southeast-oriented Silver Creek segment. Note the north-south Colfax-Dodge County line located near the figure 6 west edge. Silver Creek flows in a southeast direction from the figure 6 west center area to the figure 6 south edge in section 16. The unnamed Pebble Creek tributary flows southeast in section 31 in the figure 6 northwest quadrant and then turns in the figure 6 north center area to flow northeast to the figure 6 north edge in section 34. Note how Silver Creek has several southeast-oriented tributaries and how the Pebble Creek tributary has several north-oriented tributary valleys. Also note the presence of shallow north-south through valleys eroded into the drainage divide between the Pebble Creek drainage basin and the Silver Creek drainage basin. For example, in the section 8 northeast corner is a through valley linking a north-oriented valley with a south-oriented Silver Creek tributary valley. The through valley is only 30-40 feet deep, but does provide evidence that at one time water did flow south from the present day Pebble Creek drainage basin into what was probably a newly eroded south-oriented Silver Creek valley. Follow the drainage divide west along the boundary between section 5 and section 8 and there are two more slightly shallower through valleys, providing evidence of multiple south-oriented channels. Continue further west into sections 6 and 7 and there are other shallow through valleys linking the two drainage basins. In the figure 6 northeast quadrant, in section 3, there is a through valley linking the headwaters of a south-southeast oriented Silver Creek tributary with a north-oriented Pebble Creek tributary valley. Still another such through valley is located on the boundary between sections 9 and 10. These multiple through valleys provide evidence that prior to headward erosion of the Pebble Creek tributary valley there were multiple south-southeast oriented flood flow channels moving food waters across the figure 6 map area to what was probably then the actively eroding Silver Creek valley system. Headward erosion of the Pebble Creek tributary valley then beheaded the south-southeast oriented flood flow to the newly eroded Silver Creek valley. Flood waters on the north ends of the beheaded flood flow routes reversed flow direction to erode the north-oriented valleys. Because headward erosion of the valleys beheaded flood flow channels one channel at a time and because flood flow channels were anastomosing (interconnected), reversed flood flow in a newly beheaded channel could capture yet to be beheaded flood flow from channels further to west. The capture of such yet to be beheaded flood flow provided the water volumes required to erode the north-oriented valleys.

Dry Creek-Platte River drainage divide area

Figure 7: Dry Creek-Platte River drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 7 illustrates the Dry Creek-Platte River drainage divide area west of the  figure 4 map area and south and west of the figure 5 map area and includes overlap areas with figure 5. The north-south oriented Colfax-Dodge County line is located in the figure 7 east half. The east-northeast oriented Platte River can be seen along the east half of the figure 7 south edge. Schuyler is the town located on the figure 7 south center edge. Rawhide Creek originates north of Schuyler and flows in an east-northeast direction along the north edge of the east-northeast oriented Platte River valley/ The east-southeast oriented stream flowing along the Platte River valley north edge west of Schuyler is Shell Creek. North of Schuyler Shell Creek turns to flow south-southeast to join the Platte River east of Schuyler. Figure 7 evidence suggests that one time east-oriented flood flow in the Shell Creek channel continued east along the Rawhide Creek alignment. This evidence suggests the Shell Creek-Rawhide Creek channel and the Platte River channel were at one time anastomosing channels in an east-oriented anastomosing channel complex. North of the east-northeast oriented Rawhide Creek channel in the figure 7 east half is northeast-oriented Maple Creek. The south-southeast-oriented stream in the figure 7 northeast quadrant is the East Fork Maple Creek, which joins northeast-oriented Maple Creek near the Colfax County-Dodge County line. The south-southeast oriented stream flowing from the figure 7 north center edge is the West Fork Maple Creek, which turns to flow east and northeast to join the East Fork Maple Creek near the Colfax County-Dodge County line. The south-southeast and southeast oriented stream flowing from the figure 7 northwest quadrant is Dry Creek, which turns to flow east to join the West Fork Maple Creek. The South Fork Dry Creek originates just north of Shell Creek in the figure 7 southwest quadrant and flows northeast and east to join Dry Creek. Note the through valley linking the higher elevation northeast-oriented South Fork Dry Creek valley with the east-southeast oriented Shell Creek  channel. These east-oriented valleys need to viewed as channels in a large-scale east-oriented anastomosing channel complex. The south-southeast oriented valleys north of the east-oriented channels provide evidence of a south-southeast oriented anastomosing channel complex that was feeding large volumes of south-southeast oriented flood water into what was probably an even larger east-oriented flood. Figure 8 below provides a more detailed map of South Fork Dry Creek-Shell Creek drainage divide area.

South Fork Dry Creek-Shell Creek drainage divide area

Figure 8: South Fork Dry Creek-Shell Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 8 provides a more detailed map of the South Fork Dry Creek-Shell Creek drainage divide area seen in less detail in figure 7 above. Shell Creek flows in an east-southeast direction near the figure 7 south edge (west half). The South Fork Dry Creek originates west of figure 8 and flows east into section 13 (figure 8 west center area) and then flows in a northeast direction to the figure 8 northeast quadrant and north edge. Note the southeast tributaries flowing to northeast-oriented South Fork Dry Creek from the northwest. Also, note north and northwest oriented tributaries flowing to South Fork Dry Creek from the southeast. Several of those north and northwest oriented South Fork Dry Creek tributary valleys are linked by through valleys with the east-southeast oriented Shell Creek valley to the south. For example a south-oriented Shell Creek tributary in the northwest of section 19 is linked by a through valley with a northeast-oriented South Fork Dry Creek tributary flowing diagonally across section 18. Follow the drainage divide east from that through valley and there is an additional north-south through valley in eastern section 19 and another through valley along the boundary between sections 20 and 21. The entire South Fork Dry Creek drainage basin is at a higher elevation than the east-southeast oriented Shell Creek valley to the south. In other words, the east-oriented Shell Creek valley (which is at the north edge of the broad east-oriented Platte River valley) has eroded headward into the region and has beheaded the northeast-oriented South Fork Dry Creek drainage basin. The southeast-oriented South Fork Dry Creek tributary valleys were eroded by southeast and/or south-southeast oriented flood water moving into what was at one time the newly eroded northeast-oriented South Fork Dry Creek valley. Headward erosion of the South Fork Dry Creek beheaded the southeast and/or south-southeast oriented flood flow and flood waters on the north ends of the beheaded flood flow routes had reversed flow direction to flow north and northwest into the newly eroded and what at that time was deeper northeast-oriented South Fork Dry Creek valley. While the South Fork Dry Creek valley system was being eroded east-oriented flood from west of figure 8 map eroded the much deeper and larger east-oriented Shell Creek and Platte River valley (or channel), which beheaded east-oriented flood flow to the northeast-oriented South Fork Dry Creek drainage basin.

Elkhorn River-Maple Creek drainage divide area

Figure 9: Elkhorn River-Maple Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 9 illustrates the Elkhorn River-Maple Creek drainage divide area north and slightly west of the figure 7 map area. Stanton is the town located in the figure 9 northwest corner. The Elkhorn River is flowing in a northeast direction across the figure 9 northeast corner and north of figure 9 turns to flow southeast across the figure 9 northeast corner. From the figure 9 map area the Elkhorn River turns to flow south-southeast into the figure 5 map area. The north-northwest oriented Elkhorn River tributary south of Stanton is Butterfly Creek. South of Butterfly Creek are south-southeast oriented headwaters of West Fork Maple Creek. Further east, the north-northwest oriented tributary flowing to join the Elkhorn River at the figure 9 north edge is Cedar Creek. Continuing south-southeast on the Cedar Creek is south-southeast oriented East Fork Maple Creek. Note how Butterfly Creek and West Fork Maple Creek have the same north-northwest to south-south-southeast alignment and how north-northwest Cedar Creek and south-southeast oriented East Fork Maple Creek are on the same alignment. Figure 10 below provides a detailed map of the Cedar Creek-East Fork Maple Creek drainage divide area and demonstrates the presence of a through valley linking the opposing valleys. Named east and southeast oriented streams flowing to the figure 9 east edge from north to south are Rock Creek, North Branch Pebble Creek, Pebble Creek, and South Branch Pebble Creek. As seen in figure 5 Pebble Creek flows to the Elkhorn River. Figure 9 evidence suggests the Elkhorn River valley and its tributary valleys eroded headward to capture south-southeast oriented flood flow. Headward erosion of the South Branch Pebble Creek valley captured the flood flow first, headward erosion of the Pebble Creek valley next beheaded flood flow to the South Branch valley, headward erosion of the North Branch valley next beheaded flood flow to the Pebble Creek valley, and headward erosion of the Rock Creek valley beheaded flood flow to the North Branch valley. Headward erosion of the East and West Fork Maple Creek valleys occurred at approximately the same time with the East Fork valley eroding headward slightly in advance of the West Fork valley. Headward erosion of the Elkhorn River valley north of the figure 9 map area and then southwest into the figure 9 map area next beheaded all flood flow to the newly eroded Rock Creek valley and to the actively eroding East and West Forks of Maple Creek. Flood waters on north ends of the beheaded flood flow routes reversed flow direction to flow to the newly eroded and deeper Elkhorn River valley. The reversed flood flow eroded the north-northwest oriented Cedar and Butterfly Creek valleys and created the Elkhorn River-Maple Creek drainage divide.

Detailed map of Cedar Creek-East Fork Maple Creek drainage divide area

Figure 10 provides a detailed map of the Cedar Creek-East Fork Maple Creek drainage divide area seen in less detail in figure 9. Cedar Creek originates in the figure 10 west center area and flows east, north, and northeast to the figure 10 north center edge. From the figure 10 map area Cedar Creek flows in a north-northwest oriented direction along the alignment of the north-northwest oriented tributary joining Cedar Creek at the figure 10 north center edge. That tributary originates in the south of section 16. Cedar Creek as seen in figure 9 flows in north-northwest direction to join the northeast-oriented Elkhorn River valley as a barbed tributary. The East Fork Maple Creek originates in the figure 10 southwest quadrant and flows southeast into section 30 and then northeast into sections 20 and 21. In section 21 the East Fork Maple Creek turns to flow southeast and then south-southeast to the figure 10 south edge. East Fork Maple Creek as seen in figures 5 and 7 continues to flow in a south-southeast direction until it almost reaches the Platte River valley. Near the Platte River valley it joins Dry Creek and West Fork Maple Creek to flow in an east direction (roughly parallel to the deeper Platte River valley) to join the south-southeast oriented Elkhorn River north of Fremont (see figure 4). The north-northwest oriented Cedar Creek valley north of the figure 10 map area and south-southeast oriented East Fork Maple Creek south of the figure 10 map area are on the same alignment. Note at the south end of section 16 and north end of section 21 how the north-northwest Cedar Creek tributary valley is linked by a shallow through valley with a southeast-oriented East Fork Maple Creek tributary valley. Continue west along the Cedar Creek-East Fork Maple Creek drainage divide and there are additional shallow through valleys linking the two opposing drainage basins. The through valleys are evidence of multiple south-southeast oriented flood flow channels that once moved flood water from what is today the north-oriented Cedar Creek drainage basin to what was at that time was the actively eroding East Fork Maple Creek valley. Headward erosion of the deep Elkhorn River valley then beheaded the south-southeast oriented flood flow channels. Flood waters on the north ends of the beheaded flood flow routes reversed flow direction to erode the north-northwest oriented Cedar Creek valley and create the Cedar Creek-East Fork Maple Creek drainage divide.

Additional information and sources of maps studied

This essay has provided only a sample of the detailed topographic map evidence supporting the flood erosion interpretation. Many additional illustrations could be provided. Readers are encouraged to look at mosaics of detailed topographic maps to see the abundance of available data. Maps used in this study were created and published by the United States Geologic Survey and can be obtained directly from the United States Geological Survey and/or from dealers offering United States Geological Survey maps. Hard copy maps can also be observed at United States Geological Survey map depositories which are located throughout the United States and elsewhere. Illustrations used here were created using National Geographic Society TOPO software and digital map data. TOPO software and map data can be obtained from the National Geographic Society and/or dealers offering National Geographic Society digital map data.