S. A. Schumm
1963
<p><span>Data on the morphologic and sediment characteristics of stable </span><span class="ScopusTermHighlight">alluvial</span><span> </span><span class="ScopusTermHighlight">rivers</span><span> of the </span><span class="ScopusTermHighlight">Great</span><span> </span><span class="ScopusTermHighlight">Plains</span><span> were collected at 50 cross sections. The channel patterns of these </span><span class="ScopusTermHighlight">rivers</span><span> were classified into five types: tortuous, irregular, regular, transitional, and straight. Because no clear demarcation existed between each of the types, the pattern of the </span><span class="ScopusTermHighlight">rivers</span><span> was described by </span><span class="ScopusTermHighlight">sinuosity</span><span>, a ratio of channel length to valley length. The </span><span class="ScopusTermHighlight">sinuosity</span><span> ((P)) of these </span><span class="ScopusTermHighlight">rivers</span><span> is related to the shape of the channels expressed as a width-depth ratio (F) and to the percentage of silt and clay in the perimeter of the channel (M) as follows: Sinuous streams are characterized by a low width-depth ratio (F), a high percentage of silt-clay in the perimeter of the channel (M), a high percentage of silt-clay in the banks (although the banks of straight channels may also contain large amounts of silt-clay), and a lower gradient than straight channels having the same mean discharge. Discharge itself does not appear to affect the </span><span class="ScopusTermHighlight">sinuosity</span><span> of streams. Another possible distinction between straight and sinuous streams is in the proportions of the components of total sediment load. In a wide, shallow channel much of the sediment transported is bed-material load. In a narrow, deep channel most of the sediment transported is wash load. On the </span><span class="ScopusTermHighlight">Great</span><span> </span><span class="ScopusTermHighlight">Plains</span><span> both straight and sinuous streams may flow on the surface of </span><span class="ScopusTermHighlight">alluvial</span><span> valley fills at about the same valley slope. The departure of a stream from a straight course down the </span><span class="ScopusTermHighlight">alluvial</span><span> valley results from changes in both the caliber of the sediment load and in the relative proportions of bed-material load and wash load during the post-Pleistocene alluviation of these valleys. When during this alluviation the proportion of wash load increased, most probably by a decrease in bed-material load, the stream adjusted itself by decreasing its gradient through the development of a sinuous course. Recent changes in stream </span><span class="ScopusTermHighlight">sinuosity</span><span> in response to changes in the proportions of bed load and suspended load support this hypothesis.</span></p>
application/pdf
10.1130/0016-7606(1963)74[1089:SOAROT]2.0.CO;2
en
Geological Society of America
Sinuosity of alluvial rivers on the great plains
article