Stream sinuosity indexes are usually derived by dividing the length of a reach as measured along a channel by the length of a reach as measured along a valley. This method restricts stream sinuosity to those rivers which have downcut sufficiently to allow the formation of a floodplain. Therefore, all stream-occupied valleys in the youthful stage of erosion cannot provide a sinuosity value greater than unity, for during youth the valley and channel are coincident. It is an inherent flaw in existing indexes which suggests that all streams with a value of unity are straight, because in nature all streams have significant departures from a straight-line course and, hence, possess some degree of sinuosity. Consequently, one must assume that factors other than those which are purely hydraulic or lithologic must contribute to the sinuosity of all channels. These neglected factors are those which are topographic in origin. With this in mind, the author offers a set of indexes which takes into account both hydraulic and topographic sinuosity and which also is applicable to all streams in all portions of the cycle of erosion. HE significance of streams in the evolution T of landscapes has long fascinated geomorphologists, hydrologists, and geologists. A search of the early literature concerning streams reveals dominantly qualitative works, whereas more recent studies are characterized by quantitative and statistical methods. Part of the increased interest in quantitative inquiry results from the increased attention given to stream sinuosity. Unfortunately, most quantitative sinuosity studies restrict their measurements to hydraulic factors of channel behavior, often rendering themselves applicable only to streams whose valleys are beyond the early maturity stage of the cycle of erosion. In addition to the quantitative emphasis in recent decades has been the loss of clarity in some of the once rigidly defined qualitative terminology.It is not the purpose of this paper to condemn quantitative studies, or to escalate the significance of qualitative terminology. Rather, the author shall:
Although stream length is a fundamental property of fluvially eroded landscapes, methods of obtaining this basic measure vary; therefore, data compiled from several sources are often not comparable. Not only are measurement methods inconsistent, but there is no standaid definition of stream length itself. Most measurements are taken directly from maps where accuracy may be questionable, and air photos have proven more reliable than topographic maps. Obtaining reliable stream‐length data from published sources is perhaps the most perplexing problem of all. In investigations of stream length, therefore, it is imperative that data sources, measurement techniques, and methodology be clearly defined so that results may be studied in a meaningful context.
With the exception of urban morphology, the overall cultural influence upon cities has received inadequate attention in the field of urban geography. Yet every culture influences all aspects of its cities in a way different from all other cultures. This in turn results in modified types of cities which can be grouped according to culturalgenetic, rather than functional or economic criteria. In spite of only sporadic empirical observations in this subject, a theory of the cultural-genetic classification of cities is initiated. Future research will determine whether or not evidence in support of this theory can be produced.MPIRICAL observations of modifying E cultural influences upon the layout, vertical configuration, and architecture of cities are countlessa2 Nevertheless, a careful study of urban geographical literature reveals the lack of comparable observations in each of the other aspects of the city: social structure,
Bedrock forms of etch origin result from the interaction of groundwaters and bedrock at the weathering front at the base of the regolith. They are significant for general theories of landscape and landform genesis because they are azonal with respect both to climate and lithology. Two stages of etch form development are recognized: one involves weathering and the formation of a regolith; the second consists of stripping of the regolith and the exposure of the bedrock forms. Although etch forms have been recognized for some two centuries, the concept of etching as a process of landform development has been neglected, particularly in North America.
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