An Anthropogenic Meander Cutoff along the Ucayali River, Peruvian Amazon*

Article excerpt

      When the river is rising fast, some scoundrel whose plantation is
      back in the country, and therefore of inferior value, has only to
      watch his chance, cut a little gutter across the narrow neck of
      land some dark night, and turn the water into it, and in a
      wonderfully short time a miracle has happened: to wit, the whole
      Mississippi has taken possession of that little ditch.
      --Mark Twain, [1874] 1923

In recent years a number of authors have advanced the discussion of human-environment interactions in the Amazon Basin by presenting evidence--both contemporary and archaeological--of anthropogenic management of an environment previously regarded as "pristine" (Balee 1989; Denevan 1992; Erickson 2000a). It is estimated that humans have intervened in Amazonia since about 11,000 B.P. (Cleary 2001). So far, attention has been given particularly to the management of (agro) forests (see Denevan and Padoch 1988; Balee 1989; Anderson and others 1995; Coomes 1995) and the widespread presence of anthropogenic black earths on both the floodplain and the tierra firme (Smith 1980; Woods and McCann 1999; Hecht 2003; Lehmann and others 2003; Glaser and Woods 2004). These works lend support to the active role of humans in shaping the forest landscapes and soils of the Amazon Basin.

Less attention has been devoted to the study of river-management practices among riverine populations (see Chernela 1989; Raffles 2002; Raffles and WinklerPrins 2003). Almost four decades ago William Denevan (1966, 76) reported that meander necks were intentionally cut off to create shortcuts for canoes on the Rio Negro, a small tributary of the Baures River in the Llanos de Mojos region of Bolivia. More recently, Hugh Raffles and Antoinette WinklerPrins (2003) made the case for extensive human intervention on Amazonian fluvial systems in a review of available evidence, including their own research, published materials, and previously unavailable reports. They, too, wrote of artificial cutoffs on a tributary of the Jurua River in the state of Acre, in the western Amazon of Brazil, and in the Arapiuns Basin, near Santarem, in the eastern Amazon (Raffles and WinklerPrins 2003, 175). This field note complements the literature by reporting on a case in which Amazonian people have played a key role in facilitating a meander neck cutoff that changed the course of one of the largest rivers in the Amazon Basin, the Ucayali River of Peru.

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During 2002 and 2003 I conducted twelve months of fieldwork for my doctoral dissertation along the Central Ucayali River, near the city of Pucallpa--the fastest-growing Peruvian city in the Amazon and the main road link with Lima on the Pacific coast (Figure 1). The purpose of my dissertation is to examine how riberenos--descendants of Iberian and Amerindian people who use traditional techniques of agriculture, fishing, and forest extraction to make a living--adapt their economic livelihoods in an extremely dynamic fluvial environment such as the Ucayali and to understand how floodplain dynamics reshape the challenges and opportunities for agriculture and for natural-resource use.

Together with the Maranon River, the Ucayali forms the Amazon River proper. This turbid river drains a basin of 337,500 square kilometers (Goulding, Barthem, and Ferreira 2003, 183), an area roughly the size of Germany. Near Pucallpa the Ucayali is 0.7-1 kilometer wide (Bergman 1980, 47; Kalliola and others 1992, 77), but it can reach up to 2 kilometers in width at flood stage (Peruvian Navy 2003). The difference between low water and high water is approximately 9.3 meters at Pucallpa. At the low-water stage the discharge is 2,000 cubic meters per second; during the flood season, up to 22,000 cubic meters per second (Peruvian Navy 2003). Influenced by Andean tectonics and fluvial dynamics, the Ucayali is among the most dynamic rivers in the Upper Amazon Basin (Parssinen, Salo, and Rasanen 1996) and one of the largest actively meandering rivers in the world. …