Columbia Expedition to the Ica Valley
1952-1953

Environment of the Nazca and Ica Valleys
The Nazca Valley is unique among the numerous coastal rivers of the Peruvian littoral because it is actually the confluence of many rivers whose passage to the sea was blocked by upheaval of the coastal hills. The Rio Grande de Nazca is the portion of the river that flows from the interior valley, where the merging of rivers takes place, to the Pacific coast. There is little or no delta formation where the Rio Grande de Nazca meets the sea, as nearly all the alluvial sediments are deposited in the interior basin and along the lower courses of the individual rivers.

The Nazca and Ica rivers are fed by summer rains in the highlands. Watercourses may otherwise be dry for parts of the year. In the 1940’s the Ica river was diverted just above the Hacienda Ocucaje, rendering the previously fertile lower valley a desolate wasteland. In places along the Nazca and sister rivers, the watercourse falls into subterranean aquifers created from the soluable limestone and sandstone bedrock. These underground rivers channel much of the water through the hottest and most inhospitable parts of the lower valleys, where they might otherwise suffer complete evaporation before reaching the Rio Grande.

0-600m (0-1800 ft.)	"Chala" zone: Seasonally variable: avg. at 21.3 degrees celcius. Avg. rainfall= 0-25mm/yr.
600-2000m (1800-6000 ft.)	"Yunga" zone: Typically hot and dry. Avg. rainfall= 25-100mm/yr.
2000-3600m (6000-10800 ft)	Highland zone Avg. rainfall = 100-300mm/yr.
3600+ (10,800 ft.)	Approximate treeline--Avg. rainfall = 300-500mm/yr.

Excavation fact sheet
staff, support, resources, and objectives of the Columbia Expedition of 1952-53

Excerpts from the Expedition Notebooks
Transcription of the general notes from Burials 7, 39, 4 and 1

 

More content to come...
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