(Keen-Zebert, 2007) Bar types group together spatially in the Upper Guadalupe River. The fluvial landscape of the Upper Guadalupe river is one that is stated to be likely the result of "regional geologic structural controls, large fluctuations in discharge and sediment supply, and the geochemical and mechanical process operating on the channel bed." (Keen-Zebert, 2007) There is a macrochannel in the Guadalupe River that has resulted from "large floods [and] an active channel formed to more common flow conditions.

V. The Guadalupe River region has a 'Mixed Morphology' or to be a 'Hybrid River' in the work of Keen-Zebert (2007) entitled "Bar Spacing in Alluvial and Bedrock Reaches of the Guadalupe River, a Mixed Morphology or Hybrid River in Central Texas" states that the Guadalupe River in Central Texas is a "...mixed or hybrid streamchannel..." which is "shallowing incised into bedrock and largely overlain by thick alluvial deposits." (Keen-Zebert, 2007)

he Guadalupe River's channel distribution type and gravel bars were mapped on 140km and the grain size distribution of bars measured in the field with the bar spacing for the study reaching four times greater than the generally common range for alluvial channels. When comparisons were made between alluvial and bedrock reaches it was found that "although the percent coverage by bars is similar for both types, the bar spacing is five times greater in bedrock reaches than alluvial reaches. In several locations in both channel type reaches, bars are spaced less than one channel width and are grouped together. Grain size distributions show that there is no significant difference between bars that occur in bedrock and alluvial reaches. In the study area, grain size distributions reveal neither downstream fining nor coarsening."( Keen-Zebert, 2007)

Findings of the study state that there were few differences found in bar measurements between alluvial and bedrock reaches." (Keen-Zebert, 2007) in addition it is reported that there is no regular variation in the geologic or channel type in the bar length, density or surface grain size distribution. The Guadalupe River's bars are reported to be "complex landforms...difficult to distinguish from gravel terraces in some cases. Overall, the mixed channel while being comprised of both alluvial and bedrock sections "has...

The several segments of the Beaumont are stated to have been "contemporaneously deposited by the late Pleistocene ancestors of the modern streams that now transverse its outcrop area." (Aronow, nd)
Examination of the surface of the Beaumont on a comparative regional basis results in a "gradual loss of relict fluvial detail from northeast to southwest." (Aronow, nd) the relict fluvial topography is reflected in great detail in the Trinity and Brazos-deposited part of the Beaumont display and many miles of the relict channels on meander ridges are still intact which is stated to be a sharp contrast to "Progressive southward regional loss of detail on the Colorado, Guadalupe, and Nueces-deposited parts of the Beaumont." (Aronow, nd)

The following illustration shows the variation of the Guadalupe River geomorphic surface as compared to other Texas region rivers.

Figure 4

Channel-Floodplain Connectivity and Variation by Geomorphic Surface

Hudson (nd )

Bibliography

Keen-Zebert, Amanda (2007) Bar spacing in alluvial and bedrock reaches of the Guadalupe River, a mixed morphology or hybrid river in central Texas. Department of Geography, Texas State University -- San Marcos. San Marcos, Texas 78666-4616

Keen-Zebert, Amanda (2007) Spatial Variation of Alluvial and Bedrock

Channel Type in the Upper Guadalupe River, Texas.

Connor, Doyle, Ecology of tidal Freshwater Forested Wetlands of the Southern United States" Google Books. T

Aronow, Saul (nd) a Digression on the Origin of Some Anomalous Undrained Depressions Mostly on Pleistocene and Pliocene surfaces in the Texas Gulf Coast. Beaumont Texas.

Hudson, Paul F. (nd ) Floodplain Complexity and Connectivity of Coastal Plain Rivers. Department of Geography and the Environment.Univeristy of Texas at Austin.

http://www.twdb.state.tx.us/instreamflows/Studies/Geomorphology/PDF/Hudson.pdf