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Geomorphology of Cheyenne Bottoms

 

Geomorphology
Source of water to the bottoms is completely limited to precipitation with in the Upper Cow River Drainage Basin (Appel and Jacob, 1959). This supply of water available to the basin occurs first in the form of stream discharge then as the water pools it moves across the basin by sheet flow. Sheet flow is also known as laminar flow, surface runoff, and overland flow but will be referred to as sheet flow for this report. Intermittent streams such as Blood Creek and Deception Creek discharge directly into the Bottoms and are the primary natural inlets of the basin. The two creeks enter the flats and pools and start to flow over the bottoms in a general sheet flow migration south and east. Sheet flow is defined as a thin layer of water moving across a surface without the formation of concentrated streams of water. It is only in modern times which management practices have turned the sheet flow into channeled flow.


The initial process that occurs when this precipitation enters the bottoms is for the velocity of intermittent streams to slow rapidly and enter pools and small lakes. With a change in the rate of flow, the carrying capacity of sediment is thus changed. Carrying capacity is conceptual term defined as the amount of sediment a stream can transport under the given flow conditions. It is opinion of the author that the process of carrying capacity is by far the most important geomorphologic process at Cheyenne Bottoms. This process can be seen by the ephemeral storm events. The precipitation in the river basin is generally associated with quick short lived thunderstorms dumping larger amounts of precipitation in a relatively small amount of time. Sediment is carried in with the storm events and settles on the basins floor. There are three main natural components that this study focuses on: the overbank natural levee forming process along the stream channels, the deltaic nature of the stream/pond interface, and the sheet flow across the flat topography of the basin.


Soil
A brief analysis of the soil was noted in September, 2004. An exposure of one type of the basin's many complex soils was seen along a drainage canal that was built to drain the marsh area below the Nature Conservancy. Upon clearing the soil, a Mollic Epipedon was observed at the A horizon. This was approximately 48 inches thick from the surface. The root zone extended through out the profile, although they tend to be with in the top 70 cm. The most notable feature, which would be expected to be in a wetland area that experiences repetitive wet-dry cycles, was remnant mud cracks fill. These are vertical filled in cracks deep into the C horizon contains material the same color as the A horizon. However, absence of pressure faces or slickensides on the pedo-structure surface is evidence that this is no longer an active vertic soil. Although presence of the deep mud cracks is evidence that this is (or was) a vertic-molisol.


Soil profile taken along a drainage ditch. The flags marks the gradual boundaries between the O horizon, A horizon, and C horizon. A prominent vertical crack is seen just left of the trowel. The interpretaion of this feature is the remains of past mud cracks. Photo date 9/04, S. W. Salley

The 'mud cracks' were seen all along the exposed section. These cracks contain material that fell into the expansion cracks during a dryer period. Photo date 9/04, S. W. Salley


Small Aerial Format Photography
Cheyenne Bottoms, with its flat topography, poses problems with viewing the geomorphic patterns from the ground. To view the topography a selection of Kite Aerial Photography and Blimp Aerial Photography was picked to show elements of the drainage patterns near the Nature Conservancy.


Low oblique view of the upper marsh in the Nature Conservancy land. This picture, taken after a storm event, shows sedimentation pouring into the basin from tributary Blood Creek. Photo taken by J. S. Aber, 3/03, used with permission.
Low oblique view of the artificial dam with walk way created to divide the upper marsh. The this damn and some cattails have created a barrier for the sediment. Photo taken by J. S. Aber, 3/03 used with permission.


Elevation Modeling
Digital Elevation Models (DEM) obtained from the USGS National Elevation Dataset (NED) were used to see the drainage relationship and the surficial features. To show the position of the Galatia Channel, the overlaid Pleistocene deposits were draped onto the DEM to see relationship between the two drainage basins. The extent of the deposits were taken from Fent (1950).


DEM showing the general topography of the Cheyenne Bottoms basin. View to the north-east.  VE = 15x  (DEM Data acquired from NED and processed by S. W. Salley , 11/04)
DEM showing upstream of the paleo-drainage above the Bottoms across the Galatia Channel and into the Smoky Hills River. VE = 15x (DEM Data acquired from NED and processed by S. W. Salley , 11/04)
DEM showing the geomorphic position of Cheyenne Bottoms and the Smokey Hill River. The Galatia Channel (outlined in blue) rests on the drainage divide between the two very different geomorphic zones. (DEM Data acquired from NED and processed by S. W. Salley , 11/04)




 

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This web presentation is for the fulfillment of Field Geomorphology
as outlined in the Emporia State University's Earth Science Curriculum. 

Please direct questions to the author


S.W. Salley (2004). All rights reserved. All illustrations and ideas presented in this paper are intellectual
      property of the author. Permission must be obtained from author to use any content of this report.