Abstract

CAZENAVE, Héctor Walter. Hydrogeomorphological effects of "Casa de Piedra" dam: Temporal and spatial variations in hydrology and drainage. Rev. Univ. geogr. [online]. 2012, vol.21, n.1, pp. 59-87. ISSN 1852-4265.

The construction of Casa de Piedra dam in the final section of the high Colorado River Valley drastically modified the fluvial behavior regarding the downstream transportation of solids. Deposition of sediment material occurs due to the action of the large reservoir and gives the dam a new physical condition and some changes to the chemical characteristics of the emerging dam water which leaves the clay and silt behind. The emerging water from Casa de Piedra dam almost devoid of sediments has a greater erosive capacity than before flowing into the dam. This condition can reduce the time of formation of a meander in the area covered by this study with respect to upstream sectors of the dam. These circumstances have also generated the well-known "clear water" phenomenon. In order to test this action in a quantitative way, 25-year periods before and after the dam construction were considered. The appearance and disappearance of meanders were compared and the hydrographic changes detected through aerial photographs. The increasing number of meanders was significant for the analyzed period.

Keywords : Meander; Sediment; Erosion; Dam.