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Land-use Change and Water Quality in the Tsezhin Bii' Region, Navajo Nation

This study seeks to establish the historic and prehistoric impacts of land use in the ecologically sensitive Tsezhin Bii' region, a semi-arid region of 1800 km2 in the Navajo Nation; to discriminate between the impacts of climate change and land-use; and to determine the relationship and extent to which uranium and arsenic, associated with shallow groundwater resources and springs, has affected human health and land-use sustainability. This will provide information necessary for education and land-use planning in a severely desertified region, where rapid growth of the largest population of Native Americans may surpass the carrying capacity of lands upon which people depend for their livelihood.

To develop a detailed chronology of human demographic patterns, this work also includes an archaeological survey, and analysis of multi-date aerial photos to establish human population growth, health, movement, and settlement. Geological and biological disciplines are combined with archaeology to decipher unexplained population shifts revealed by the archaeological record. Navajo oral history provides additional insight about significant changes in the physical and biological environment in historic times.

The Tsezhin Bii' are erosion resistant remnants of diatremes and maar volcanoes. Springs and water wells are located within diatreme structures and in shallow alluvial deposits. Examination of geologic controls on the locations of springs and well sites relative to volcanic deposits and pre-volcanic strata is crucial to characterize the sensitivity of local aquifer systems to climate change, as well as the effects of geology and climate on water quality. Detailed geologic field mapping with an emphasis on volcanic and sedimentary facies, structures, and fractures is required to establish the relations of geologic features to groundwater flow and local contamination.

For more information, select from the following topics:

• Groundwater and spring-water quality
• Insights into changes over the past century - interviews with elders
• Mapping and geologic framework
• Development of K-12 culturally based earth-science curriculum