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Endorheic drainage basins, those inland basins not connected directly to ocean, are essential for hydrological modeling of global and regional water balances, land surface water storage, gravity anomalies, sea level rise, etc. Within many hydrological model frameworks, river basins are defined by digital river networks through their flow direction and connectivity datasets. Here we present an improvement to gridded flow direction data and its derivatives produced from upscaled global 5 and 15 arc minute MERIT networks. We explicitly label endorheic and exorheic drainage basins and alter the delineation of endorheic basins by merging small inland watersheds to the adjacent host basins. The resulting datasets have a significantly reduced number of endorheic basins while preserving the total land portion of those basins since most of the merged catchments were inside other larger endorheic areas. We developed and present here the endorheic basin delineation method. This method performs an analysis of the contributing river and basin geometry relative to the location of the flow end point (i.e. potential endorheic lake), proximity of the latter to the drainage basin boundary and the elevation difference between the basin's lowest point and potential spillover location at the basin boundary. The new digital river network was validated using the University of New Hampshire Water Balance Model by comparing the water balance of endorheic inland depressions with modeled accumulation of water in their inland lakes based on the observed historical climate drivers used by WBM.
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Tectonically controlled drainage fragmentation in the southwestern Great Basin, USA
The area now occupied by the Great Basin, western USA, contained paleo-fluvial systems that predated the modern-day endorheic (closed) basins. The areal extent of these paleo-fluvial systems within the southwestern Great Basin is known mainly from isolated remnants preserved in the modern mountain ranges. We document the age, extent, and tectonic disruption of Mio-Pliocene fluvial systems of the southwestern Great Basin. Synthesis of new field observations, geochemistry, and geochronology with existing studies defines two latest Miocene to Pliocene east-southeast flowing drainages that predated the modern endorheic basins. The drainage network was ultimately fragmented in Pliocene time (ca. 3.5-4 Ma). Fragmentation of the drainage network led to lake formation, drying of lakes, and the formation of isolated springs. The rapid environmental changes initiated by faulting and volcanism isolated previously interbreeding populations of spring-dwelling taxa and have caused divergent evolution since Pliocene time. Modern endemism within the region’s springs is thus a direct consequence of intraplate tectonism.
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- Award ID(s):
- 1516680
- PAR ID:
- 10394678
- Date Published:
- Journal Name:
- GSA Bulletin
- ISSN:
- 0016-7606
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1130/B36563.1
