Polynesian and Hohokam irrigation technique comparison

Polynesia is located in a tropical to subtropical zone, and the islands are comprised mostly of volcanic rock [Kirch and Lepofsky, 1993]. In Polynesia, they have developed some interesting traditional irrigation systems, still used to this day [Kirch and Lepofsky, 1993]. Two irrigation systems were developed: the pondfield system, and the raised-bed system – both developed around A.D. 500 [Kirch and Lepofsky, 1993]. In areas with sloped terrain, pondfield irrigation is used by creating terraces such that water flows from upper terraces to lower terraces, increasing the retention time and regulating water level [Ladefoged, Kirch, et al., 2009]. In swamps, raised-bed irrigation is used by mounding soil into beds, and allowing drainage between the mounds to regulate water content [Kirch, 1978].

In contrast, The Hohokam developed their techniques in southern Arizona, which has an arid desert climate with relatively flat topography [Woodbury, 1961]. The Hohokam hand dug a series of canals, diverting water for irrigation that became the template for modern canals in the area [Woodbury, 1961]. The first canals were dug sometime between A.D. 500 and 800, with approximately 185 miles of canal providing for 80 miles of irrigated land along the canal system [Woodbury, 1961]. The canal system developed by the Hohokam was used for approximately a century before being abandoned sometime between A.D. 1450 and European contact in A.D. 1650 [Dean, 2007].

Even though the two societies developed their techniques in completely different hydrologic environments, they are not unlike one another. The purpose of Polynesian irrigation was to increase productivity in an island setting, while the purpose of Hohokam irrigation was to increase productivity in a desert setting. While both are effective water management schemes, in Polynesia they contended with managing water in excess, and the Hohokam contended with water scarcity; yet, in either case: irrigation was used to increase productivity. Therefore, independently, both societies modified their environment to create what are essentially islands of maximum productivity within the same period – even though Polynesian society has outlasted the Hohokam.

References

Dean, R. M. (2007), Hunting intensification and the Hohokam “collapse,” Journal of Anthropological Archaeology, 26(1), 109-132, doi:doi:10.1016/j.jaa.2006.03.010.

Kirch, P. V. (1978), Indigenous Agriculture on Uvea (Western Polynesia), Economic Botany, 32(2), 157-181.

Kirch, P. V., and D. Lepofsky (1993), Polynesian Irrigation: Archaeological and Linguistic Evidence for Origins and Development, Asian Perspectives, 32(2), 183-204.

Ladefoged, T. N., P. V. Kirch, S. M. Gon III, O. A. Chadwick, A. S. Hartshorn, and P. M. Vtousek (2009), Opportunities and constraints for intensive agriculture in the Hawaiianarchipelago prior to european contact, Journal of Archaeological Science, 36(10), 2374–2383, doi:doi:10.1016/j.jas.2009.06.030.

Woodbury, R. B. (1961), A Reappraisal of Hohokam Irrigation, American Anthropologist, 63(2), 550-560.