Persistence of Features in an Arid Landscape

IN arid regions where sparse vegetation leaves bare every lineament of the scarred face of nature questions of the origin and persistence of the landscape force themselves on our attention. Intricate but boldly carved canyons, cliff and precipice ornamented with pillars and pinnacles delicately poised, waterless stream channels strewn with the litter of floods-all these testify to erosive processes obviously now in action and apparently of almost catastrophic violence. Ancient as the seems an ironic phrase. It is easy to lose perspective and to conceive of the rate of erosion as much more rapid than it is in fact. Opportunities to gain a conception of the rate of erosion are rare, and actual measurement scarcely practicable with present methods and facilities. The best estimates of erosion are indirect: instead of measuring loss of volume of the hills we measure the material carried by streams in solution and in suspension at some point near their mouths. By this method it is estimated that the surface of the United States is being removed at the rate of one inch in 760 years, whereas in the Mississippi River drainage basin the wastage is one inch in 500 years, and in the Colorado River drainage basin the rate is slightly more rapid, or one inch in 440 years. The mud and the invisible salts have been derived from the whole watershed, and we have no way of knowing how much came from this or that place. Any opportunity of making a direct estimate of comparative rates of erosion, quantitative or qualitative, is therefore most welcome. Such an opportunity occurred to the writers in southeastern Utah. The observation had been planned for some years by Mr. Bryan, and the chance of carrying it out came to Mr. La Rue in 1925 during the course of an engineering investigation

Archaeology · Arid · Biology · Geography · Navajo · Persistence (discontinuity · Archaeology and Natural History · Ecology · Geology · Hydrology and Sediment Transport Processes · Soil erosion and sediment transport

• El estudio del paisaje por medio de la fotografía

  Open Access•Ignacio Bisbal Grandal•2016

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