ANCIENT KARIZ GROUNDWATER ACQUISITION SYSTEMS IN THE CONTEXT OF THE SOUTHERN AFGHANISTAN LANDSCAPE

Kariz (a.k.a. qanats, karez, fuqara) are groundwater extraction systems consisting of low-gradient tunnels excavated within alluvial fans via a series of vertical access shafts called “chahs,” which are identifiable by their characteristic rim of excavated fill (spoil). These systems, which originated in pre-Achaemenid Persia, reached Afghanistan about 2,500 BP and are important features particularly in southern and southeastern Afghanistan, e.g., Kandahar area. This investigation is examining the relationship between kariz character and distribution and the morphology of alluvial fans and associated wadi systems, as well as the hydrogeology. Related inquiry is examining how this relationship has evolved in response to environmental change during the past two millennia. Our research is being conducted in a GIS environment using an array of data sources, e.g., LiDAR, IFSAR, Orthophotography, Corona and other conventional aerial photography, SPOT and Landsat imagery, U.S. Geological Survey geology mapping, and Soviet-era topographic maps. High-resolution LiDAR, orthophotography, and SPOT imagery are being used to map elements of the kariz-occupied landscape and to derive terrain models. Ongoing in-country geologic fieldwork being conducted by U.S. Army Corps of Engineers geologists, including terrain mapping, soil and sediment sampling (e.g., trenching, wadi walls), and sampling for luminescence dating (e.g., wadi fill, chah spoil), provides valuable ground-truthing for these interpretations. In addition, groundwater modeling shows that, due to their design and dependence on groundwater (derived from Hindu Kush snowmelt and rain), kariz are far less sensitive to year-to-year variation in precipitation than surface water flow, which makes them relatively robust sources of irrigation and domestic water.