A geomorphic history based on topographic map evidence

The Loup River-Platte River drainage divide area between Kearney and Columbus records the history of two immense converging glacial melt water floods during their central Nebraska flood flow events. An immense southeast-oriented flood flowed from the northwest into Nebraska, where late during the flood history it was captured by headward erosion of the large Platte River valley. The Platte River valley eroded headward to the Rocky Mountains west of Nebraska, where additional southeast-oriented flood water was captured. The east-oriented flood water in the Platte River valley converged with southeast-oriented flood flow moving across the present day Loup River drainage basin and the combined flood flow moved northeast and east in the large northeast and east oriented Platte River valley. Flood waters from the northwest were forced by flood waters from the west to flow along the northwest wall of the large northeast-oriented Platte River valley while flood waters from the west flowed along the Platte River valley’s southeast wall. The present day Loup River channel location along the northwest edge of the large northeast-oriented Platte River valley is evidence of flood flow routes just prior to cessation of the massive glacial melt water floods.

• The purpose of this essay is to use topographic map interpretation methods to explore Loup River-Platte River drainage divide area landform origins between Kearney and Columbus, 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 essay 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 the 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 Loup River-Platte River drainage divide area landform origins between Kearney and Columbus, 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.

Loup River-Platte River drainage divide area location map

Figure 1: Loup 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 Loup River-Platte River drainage divide area between Kearney and Columbus, Nebraska, USA. The west to east oriented Nebraska-Kansas state line is located near the figure 1 south edge. Nebraska is the state north of that state line and occupies most of the figure 1 map area. The Platte River flows from North Platte in the figure 1 west center in a southeast direction to Kearney. From Kearney the Platte River flows in a northeast direction to Columbus and North Bend. At North Bend the Platte River begins to turn so as to flow south along the figure 1 east edge and then abruptly turns to flow east to join the south-southeast oriented Missouri River located just east of the figure 1 map area. Southeast-oriented Loup River tributaries flow from the figure 1 northwest quadrant area, and from north to south include the North Loup River, which flows through Purdum, Brester, Taylor, Burwell, Ord, North Loup, Cotesfield, and Elba before joining the northeast-oriented Loup River; the Middle Loup River, which flows through Seneca, Thedford, Dunning, Sargent, Arcadia, and Loup City before joining the northeast-oriented Loup River near Boelus; and the South Loup River, which flows through Stapleton, Arnold, and Callaway before turning near Pleasanton to flow in a northeast direction to become the northeast-oriented Loup River. The northeast-oriented Loup River after flowing parallel to the northeast-oriented Platte River for a considerable distance finally joins the Platte River near Columbus. Note how in the Columbus area, Shell Creek, which flows in a southeast direction towards Columbus, turns to flow in an east-direction roughly parallel to the Platte River before finally joining the Platte River near Schuyler. Also note just southwest of the South Loup River is the southeast and northeast oriented Wood River, which also flows parallel to the Platte River for a considerable distance before joining the Platte River. In fact a study of figure 1 and of more detailed maps reveals that all central and eastern Nebraska southeast-oriented streams north of the Platte River valley upon reaching the Platte River valley north edge, turn to flow parallel to the Platte River channel and only join the Platte River after flowing roughly parallel to the Platte River channel for considerable distances along the north edge of the broad Platte River valley. Detailed maps below illustrate evidence supporting this observation. The reason for this unusual phenomena is this region in central and eastern Nebraska is where two massive glacial melt water floods converged. One flood moved in a southeast direction while the other flood had moved in a southeast direction in the Rocky Mountain region to west and was captured by headward erosion of the South and North Platte River valleys to the west of the figure 1 map area. Southeast-oriented flood waters from the northwest upon entering what was then the flood filled Platte River valley were forced to flow along the north edge of the large valley while flood waters from the west filled the valley further to the southeast. Present day river channel locations reflect the locations of the converging flood currents just prior to the time flood flow ceased.

Loup River-Platte River drainage divide area detailed location map

Figure 2: Loup 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 somewhat more detailed location map for the Loup River-Platte River drainage divide area between Kearney and Columbus. Valley, Greeley, Nance, Platte, Sherman, Howard, Merrick, Polk, Buffalo, Hall, Hamilton, and York are Nebraska county names and the county boundaries are shown. Kearney is located in the figure 2 southwest corner and Columbus is located near the figure 2 northeast corner. The Platte River flows in a northeast direction from Kearney to Columbus. The South Loup River flows in a southeast direction to Pleasanton in northern Buffalo County and then turns to flow in a northeast direction to become the northeast-oriented Loup River, which finally joins the Platte River near Columbus. Proceeding in a northeast direction from Pleasanton (near the figure 2 west edge in north Buffalo County) the major southeast-oriented Loup River tributaries flowing to join the northeast-oriented South Loup River-Loup River are Mud Creek, which joins the northeast-oriented river at Ravenna; Middle Loup River, which joins the northeast-oriented Loup River near Boelus (Howard City); the North Loup River, which joins the northeast-oriented Loup River downstream from St Paul; Cedar River, which joins the northeast-oriented Loup River near Fullerton; and Beaver Creek, which joins the Loup River near Genoa. In addition to the major southeast-oriented Loup River tributaries note the presence of many other shorter southeast-oriented Loup River tributaries. These multiple southeast-oriented Loup River tributaries provide evidence of a massive southeast-oriented flood, which flowed from the northwest into what was at one time the newly eroded northeast-oriented Loup River-Platte River valley (as seen in detailed maps below the Loup River channel downstream from the Grand Island area is located along the northwest edge of the large northeast-oriented Platte River valley and the parallel Platte River channel is located further to the southeast in that large northeast-oriented Platte River valley. Note the presence of several northeast-oriented streams located in the Platte River valley between the northeast-oriented Loup River channel and the northeast-oriented Platte River channel. Downstream from Grand Island these northeast-oriented streams include Prairie Creek, Moores Creek, Silver Creek, and the Wood River. Upstream from Grand Island these northeast-oriented are located in the large Platte River valley, although the South Loup River is located in a separate valley of its own. Again, what has happened to create these multiple parallel channels in the broad northeast-oriented Platte River valley is two large glacial melt water floods converged in the northeast-oriented Platte River valley. Southeast-oriented flood waters flowing into the flood filled Platte River valley from the northwest were forced to flow along the valley’s northwest wall while flood waters from the west filled the Platte River valley to the southeast of that northwest wall area.

Loup River-Platte River drainage divide area west of Columbus

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

Figure 3 illustrates the Loup River-Platte River drainage divide area west of Columbus. Columbus is the city in the figure 3 east center area. The northeast and east oriented Platte River flows from the figure 3 southwest corner area to the figure 3 east center edge. The Loup River flows in a northeast direction in the figure 3 west center area and then turns to flow in a southeast direction to join the Platte River near Columbus (do not confuse the Loup River channel with the parallel canal). The southeast-oriented tributary joining the Loup River near the figure 3 west edge is Beaver Creek and the town located near where Beaver Creek flows to the Loup River is Genoa. Figure 3 illustrates the width of the large Platte River valley in the Columbus area (the grid squares are one mile on a side). Note how the Loup River channel near the figure 3 west edge is located along the northwest edge of the large Platte River valley while the Platte River channel is ten or more miles to the southeast, although located on the floor of the same large northeast oriented valley. The southeast-oriented stream in the figure 3 north center edge area is Shell Creek. Evidence for southeast-oriented flood flow in the drainage divide area between Shell Creek and Beaver Creek and in the Elkhorn River-Shell Creek drainage divide area is described in essays for those drainage divides that can found under Loup River on the sidebar category list. Note how Shell Creek flows in a southeast direction to enter the large east-oriented Platte River valley, and then upon entering the Platte River valley promptly turns to flow east along the large east-oriented Platte River valley’s north edge. A close look at figure 3 reveals through valleys linking the Loup River channel with the east-oriented Shell Creek channel segment, suggesting that at one time water did flow east from the Loup River channel to the Shell Creek channel. Why are the Loup River channel and the Shell Creek channel separate from the Platte River channel today and why does the Loup River channel join the Platte River in this figure 3 location? As already described a massive southeast-oriented flood flowed into what was then a newly eroded northeast and east oriented Platte River valley and joined a large flood from the west. The western flood waters occupied the south and middle of the large Platte River valley and the converging southeast-oriented flood flow was forced to flow along the Platte River valley’s northwest and north edge. Once flood flow ended present day river and stream channels developed along the routes the flood waters had followed. Apparently as flood flow ended flood waters in the Shell Creek drainage basin were able to transport and deposit enough sediments in the Platte River valley to deflect the Loup River channel to the southeast, causing the Loup River channel to flow to the Platte River channel.

Loup River-Platte River drainage divide area southeast of Fullerton

Figure 4: Loup River-Platte River drainage divide area southeast of Fullerton. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 4 illustrates the Loup River-Platte River drainage divide area southwest of the figure 3 map area and includes overlap areas with figure 3. The northeast-oriented Platte River channel flows from the figure 4 south edge to the figure 4 east edge. The northeast-oriented Loup River channel flows from the figure 4 west center edge to the figure 4 north edge (near the town of Genoa). As seen in figure 3 Genoa is located near where southeast-oriented Beaver Creek joins the northeast-oriented Loup River. The Beaver Creek-Cedar Creek drainage divide area essay describes evidence for southeast-oriented flood flow in that region. Note how the northeast-oriented Loup River channel is located along the northwest wall of the large northeast-oriented Platte River valley and the Platte River channel (near the figure 4 south edge) is located along the wide valley’s southeast wall. Cedar River is the southeast-oriented stream flowing from the figure 4 northwest corner to join the Loup River near the town of Fullerton. Prairie Creek is the northeast-oriented stream located between the Loup River and the Platte River channels flowing from the figure 4 southwest corner area. Silver Creek is another northeast-oriented channel located between the northeast-oriented Prairie Creek channel and the northeast-oriented Platte River channel. The Silver Creek channel joins the Platte River channel in the figure 4 east center area. Note how Prairie Creek after flowing between the two major northeast-oriented channels turns to flow east to join the Platte River channel near the figure 4 east edge. This change in the Prairie Creek channel location is immediately downstream from where southeast-oriented Cedar River enters the large northeast-oriented Platte River valley. Again, probably late during the final flood events southeast-oriented flood flow in the Cedar River valley was able to transport and deposit enough sediments in the Platte River valley that it was able to divert the northeast-oriented Prairie Creek channel to the join the Platte River channel. This Prairie Creek channel diversion, like the Loup River channel diversion seen in figure 3, suggests flood flow from the northwest continued slightly longer than did flood flow from the west. Again, the location of the various channels reflects how flood waters converged. The Platte River channel along the large northeast-oriented valley’s southeast wall was where flood waters from the west were forced to flow as converging flood waters from the northwest entered the large northeast-oriented valley. The Loup River valley along the large northeast-oriented valley’s northwest wall is where southeast-oriented flood waters entering the large northeast-oriented valley were forced to flow by flood waters from further to the west. The Prairie Creek channel reflects where flood waters that entered the large Platte River valley further to west were forced to flow between what were then the northeast-oriented Platte River and Loup River flood flow channels.

Loup River-Platte River drainage divide area east of St Paul

Figure 5: Loup River-Platte River drainage divide area east of St Paul. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 5 illustrates the Loup River-Platte River drainage divide east of St Paul and is located south and west of the figure 4 map area and includes overlap areas with figure 4. St Paul is the town located in the figure 5 west center edge area. Central City is the town located in the figure 5 southeast quadrant and Fullerton is the town located in the figure 5 northeast corner. The northeast-oriented Platte River channel is located in the figure 5 southeast corner. The Loup River flows northeast just south of St Paul and joins the east-oriented North Loup River just to the northeast of St Paul and then turns to flow east and northeast to the figure 5 northeast corner. The southeast-oriented river joining the Loup River in the figure 5 northeast corner is Cedar River (see figure 4). The North Loup River west and north of the figure 5 map area is a southeast-oriented river. Evidence for southeast-oriented flood flow in the Cedar River-North Loup River drainage divide area has been described in the essay describing that region. Again, note how the Loup River channel is located along the large northeast-oriented Platte River valley northwest wall. The large valley’s southeast wall is located just southeast of the figure 5 map area and the Platte River channel is located near that southeast wall. Prairie Creek is the northeast-oriented stream located between the northeast-oriented Loup River channel and the northeast-oriented Platte River channel. Between Prairie Creek and the Platte River channel are other northeast-oriented channels, including the northeast-oriented Moores Creek channel and the northeast-oriented Silver Creek channel. The Prairie Creek channel will be followed headward in figures below so as to show where southeast-oriented flood waters in that channel entered the Platte River valley. East of St Paul is what appears to be an area of sand dunes located between the Loup River channel and the northeast-oriented Prairie Creek channel. The sand dunes may have formed on deltaic deposits formed where flood waters from the southeast-oriented North Loup River entered the large northeast-oriented Platte River valley. Again, apparently flood flow from the west diminished before flood flow in the North Loup River valley ended. There was sufficient flood flow in the Loup River channel to keep that channel open, however sediments transported from the North Loup River drainage basin were deposited on the Platte River valley floor and there was not enough flood flow from the west to carry all of the sediments downstream. While not visible in figure 5, the Wood River channel joins the Platte River just upstream from the figure 5 map area and the North Loup River deposition may have helped deflect that channel (see figure 6).

Loup River-Platte River drainage divide area north of Grand island

Figure 6: Loup River-Platte River drainage divide area north of Grand island. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 6 illustrates the Loup River-Platte River drainage divide area north of Grand Island and south of St Paul and is located south and slightly west of the figure 5 map area and includes overlap areas with figure 5. The northeast-oriented Platte River is located in the figure 6 southeast quadrant and is flowing along the southeast wall of the wide northeast-oriented Platte River valley. The northeast-oriented Loup River is located in the figure 6 northwest quadrant and is flowing along the northwest wall of the wide northeast-oriented Platte River valley. Grand Island is the city located along the figure 6 south center edge. Central City is the town located along the figure 6 east edge just north of the Platte River. St Paul is the town located along the figure 6 north edge just west of the Loup River. The northeast-oriented stream located between Grand Island and the northeast-oriented Platte River channel is Wood River. Wood River is a southeast-oriented river, which flows into the northeast-oriented Platte River valley near Kearney (see figure 10) and then like Prairie Creek and the Loup River flows in a northeast direction parallel to the northeast-oriented Platte River channel. Note how the northeast-oriented Wood River channel joins the Platte River channel just to the northeast of Grand Island. Figure 10 below illustrates where the southeast-oriented Wood River valley enters the northeast-oriented Platte River valley near Kearney and figure 7 illustrates the parallel Wood River and Platte River channels southwest of the figure 6 map area. The northeast-oriented Prairie Creek channel is located between the Loup River channel and the Platte River channel and the Silver Creek channel is located between the Prairie Creek channel and the Platte River channel. Figures 7,8, and 9 illustrate where southeast-oriented flood flow responsible for the Prairie Creek channel entered the northeast-oriented Platte River valley. Again, as southeast-oriented flood flow from the northwest entered the large northeast-oriented Platte River valley the flood waters were forced by flood waters from further to the west to flow along the northwest wall of the northeast-oriented Platte River valley while flood waters from further west flowed further to the southeast in the valley. Present day northeast-oriented channels on the floor of the wide Platte River valley are relics left from flood flow routes that existed just prior to the cessation of the immense glacial melt water floods.

Loup River-Platte River drainage divide area west of Grand island

Figure 7: Loup River-Platte River drainage divide area west of Grand island. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 7 illustrates the Loup River-Platte River drainage divide area west of Grand Island and is located west and south of the figure 6 map area and includes overlap areas with figure 6. Grand Island is the city located along the figure 7 east center edge. The Platte River channel is located in the figure 7 southeast corner. Between the northeast-oriented Platte River channel and Grand Island is the northeast-oriented Wood River channel, which is paralleling the adjacent Platte River channel. The South Loup River is located in the figure 7 northwest corner area and flows in an east and northeast direction from the figure 7 west edge to join the southeast-oriented Middle Loup River near the figure 7 north center edge and the combined river then flows to the figure 7 north edge. Note how the South Loup River is flowing in a valley of its own and is not located in the large northeast-oriented Platte River valley to the south. The area north of Grand Island, where the Middle Loup River joins the South Loup River is where the Loup River enters the Platte River valley and then flows northeast along the Platte River valley’s northwest until joining the Platte River channel at Columbus (as seen in figure 3). West of Grand Island the channel located along the Platte River valley’s northwest wall is the Prairie Creek channel. Note how the northeast-oriented Prairie Creek channel has southeast-oriented tributaries flowing from the higher region immediately west of Grand Island. Figures 8 and 9 provide more detailed maps of the Prairie Creek headwaters area. Also note how the northeast-oriented Prairie Creek channel has been deflected to flow in an east-southeast direction toward Grand Island before turning to flow northeast again. Deflection of the Prairie Creek channel is probably related to deltaic sediments deposited on the Platte River valley floor by the South Loup River and Middle Loup River where they enter the Platte River valley. In the figure 7 south half, northeast-oriented channels in the large northeast-oriented Platte River valley from northwest to the southeast include the Prairie Creek channel, the Wood River channel, and the Platte River channel. Further to the northeast in figure 7 the Loup River channel is located northwest of the Prairie Creek channel and the Wood River channel joins the northeast-oriented Platte River channel.

South Loup River-Prairie Creek drainage divide area west Cairo

Figure 8: South Loup River-Prairie Creek drainage divide area west Cairo. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 8 provides a more detailed map of the South Loup River-Prairie Creek drainage divide area west of Cairo, which was seen in less detail in figure 7 above. Cairo is the town located in the figure 8 northeast quadrant near the figure 8 east edge. Prairie Creek flows in a northeast direction in the figure 8 southeast corner area. Flash Creek is the named southeast-oriented Prairie Creek tributary in Hall County joining Prairie Creek near the figure 8 south edge. As seen in figure 7 Prairie Creek derives its water from southeast-oriented streams like Flash Creek and these streams all originate today on the South Loup River-Prairie Creek drainage divide area seen in figure 8 and also to the southwest of figure 8. The South Loup River flows in an east direction along the figure 8 north edge (west half) and then turns to flow in a northeast direction to the figure 8 north edge. Sweet Creek is the northeast-oriented South Loup River tributary flowing from the figure 8 west center edge to join the South Loup River near the Buffalo-Hall County border. Antelope Valley is the named north oriented Sweet Creel tributary valley located in the figure 8 southwest quadrant. Cherry Creek is the named north and north-northeast oriented Sweet Creek tributary located just west of the figure 8 center area. Figure 9 below provides an even more detailed map of the Cherry Creek-Flash Creek drainage divide area and illustrates through valleys crossing that drainage divide. Similar through valleys link other north-oriented Sweet Creek tributaries with the southeast-oriented Prairie Creek tributaries further to the southwest. These through valleys provide evidence of multiple south-southeast oriented flood flow channels that moved south-southeast oriented flood flow into what was at that time a newly eroded and deep northeast-oriented Prairie Creek-Wood River-Platte River valley. At that time the South Loup River valley did not exist nor did the northeast-oriented Sweet Creek valley or any of its tributary valleys exist. Flood waters were flowing directly from the northwest into the newly eroded northeast-oriented Platte River valley. Headward erosion of he South Loup River-Sweet Creek valley from the newly eroded northeast-oriented Platte River valley next beheaded the south-southeast oriented flood flow routes and diverted the flood water northeast into the northeast-oriented Plate River valley. The Sweet Creek valley eroded headward slightly ahead of the South Loup River valley and the north-northeast-oriented Cherry Creek valley eroded headward slightly ahead of the Sweet Creek valley west of Cherry Creek. The north-northeast-oriented Cherry Creek valley beheaded southeast-oriented flood flow routes and flood waters on the north-northwest ends of the beheaded flood flow routes reversed flow direction to erode the present day north-northwest oriented Cherry Creek tributary valleys seen in figure 8.

Detailed map of Cherry Creek-Flash Creek drainage divide area

Figure 9: Detailed map of Cherry Creek-Flash Creek drainage divide area. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 9 provides an even more detailed map of the Cherry Creek-Flash Creek drainage divide area seen in less detail in figure 8 above and in even less detail in figure 7 above. Flash Creek headwaters are located in sections 7, 13 and 18 and Flash Creek flows in a southeast direction across section 20 to the figure 9 southeast corner area and then to northeast-oriented Prairie Creek. South and southeast oriented drainage in sections 8, 9, 17, and 16 flows to northeast-oriented Prairie Creek. North-oriented drainage in sections 14, 11, and 12 and north of section 7 flows to Cherry Creek, which flows to northeast-oriented Sweet Creek and then to the South Loup River. Note the upland erosion surface found on some of the drainage divides. That upland erosion surface was formed prior to headward erosion of he deep northeast-oriented Platte River valley when south-southeast oriented flood waters flowed across the entire present day Loup River-Platte River drainage divide region on an upland surface equivalent in elevation to the surface seen here. Headward erosion of the deep northeast-oriented Platte River valley captured the south-southeast-oriented flood water and diverted the flood water northeast and east. Present day southeast-oriented valleys then eroded headward from the newly eroded Platte River valley northwest wall. Those valleys eroded headward along flood flow routes and to a limited degree across the flood flow routes. The southeast-oriented Flash Creek valley was one of the valleys that eroded headward along southeast-oriented flood flow routes from the northeast-oriented Platte River valley. Headward erosion of the Flash Creek valley captured several south-southeast oriented flood flow routes and these tributary valleys were eroding channels headward when headward erosion of the deep South Loup River-Sweet Creek-Cherry Creek valley to the north beheaded the south-southeast oriented flood flow routes to the newly eroded Flash Creek drainage basin. The south-southeast oriented flood flow routes were beheaded one channel at a time from the east to the west. Flood waters on the north ends of the beheaded flood flow channels reversed flow direction to flow north to the newly eroded and deeper north and northeast oriented Cherry Creek-Sweet Creek valley. This reversal of flood flow erode the north and northwest oriented Cherry Creek tributary valleys and also created the present day Cherry Creek-Flash Creek drainage divide. Notice how the present day Cherry Creek-Flash Creek drainage divide in the figure 9 map area is crossed by shallow through valleys linking the heads of north-oriented Cherry Creek tributary valleys with heads of south-oriented Flash Creek tributary valleys. Those through valleys provide evidence that multiple channels of south-oriented flood water once flowed across the Cherry Creek-Flash Creek drainage divide.

South Loup River-Platte River drainage divide area north of Kearney

Figure 10: South Loup River-Platte River drainage divide area north of Kearney. United States Geological Survey map digitally presented using National Geographic Society TOPO software.

Figure 10 illustrates the South Loup River-Platte River drainage divide area north of Kearney and is located  south and west of the figure 7 map area and includes overlap areas with figure 7 (and also figures 8 and 9). Kearney is located near the figure 10 south edge. The South Loup River is the southeast and northeast oriented river located along the figure 10 north edge (west half). Note the South Loup river is flowing in a valley of its own, quite independent from the southeast and northeast oriented Platte River valley to the south. The southeast and northeast oriented Platte River valley is located along the figure 10 south edge and is southeast-oriented west of Kearney and northeast-oriented east of Kearney. The Wood River is the southeast-oriented river flowing from the figure 10 west center area to enter the northeast-oriented Platte River valley just north of Kearney. Note how the Wood River east of Kearney is flowing in a northeast-oriented channel parallel to the northeast-oriented Platte River, but is not flowing to the Platte River channel. Also note the Buffalo-Hall County border line in the figure 10 northeast corner. That county line was seen in figure 8 and southeast-oriented streams just north of the Platte River valley’s northwest margin are flowing to northeast-oriented Prairie Creek, located along the Platte River valley’s northwest wall near the figure 10 east edge. Prior to headward erosion of the South Loup River valley flood waters flowed south and southeast across the present day upland region between the South Loup River valley and the Platte River valley. And, prior to headward erosion of the northeast-oriented Platte River valley flood waters flowed south and southeast across the entire figure 10 map area. Headward erosion of the northeast-oriented Platte River valley captured the southeast-oriented flood flow and diverted the flood waters to the northeast and east. Flood waters from west of the figure 10 map area flowed along the Platte River valley’s southeast wall and flood waters entering the Platte River near Kearney flowed northwest of those western flood waters in the valley. As additional southeast-oriented flood waters (such as the south-southeast-oriented flood water to the northeast-oriented Prairie Creek channel) entered the Platte River valley to the northeast those additional flood waters replaced the Wood River flood flow channel as the flood flow channel closest to the Platte River valley’s northwest wall. This process was repeated downstream along the wide Platte River valley almost all the way to the Missouri River valley.

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.