Modeling the connections between internally and externally drained basins using GIS,Google Earth©,and remote sensing

Abstract

The development of internal drainage is intimately tied to the tectonic and climatic history of an area, but research into the exact causes and processes of internal drainage is constrained by the ability to accurately delineate both internally and externally draining watersheds. Until recently, existing global catalogs of internally drained regions were either hand-drawn or based upon digital elevation models whose resolution is much lower than those currently available. Here, the World Wildlife Fund’s HydroBASINS dataset is analyzed in a GIS program to identify points of former connectivity between endorheic and exorheic basins, to identify possible palaeolakes and palaeo-distributary channels, and to quantify on a global basis the extent of area lost to internal drainage for 101 large watersheds. The results have been made available in Google Earth^© KMZ files, and a sample workflow is presented which uses the data to approximate the relative importance of tectonic vs climatic factors in initiating endorheism. As an example of how the dataset and workflow can be used, the drainage history is modeled for endorheic watersheds within two very different tectonic regimes, the Afar region of northeastern Africa and the Northern Territory of Australia. The methodology is readily adaptable to other endorheic basins and offers the ability to create drainage history models which can help in research areas such as climate change investigations and groundwater and economic mineral prospecting.