2013 NGWA Summit — The National and International Conference on Groundwater

In the Footsteps of Early Researchers: Evolving Hydrologic Understanding in the California Desert

Monday, April 29, 2013: 4:20 p.m.
Regency East 3 (Hyatt Regency San Antonio)
Andy Zdon, P.G., C.E.G., C.Hg., Johnson Wright, Inc.

Hydrogeologic research frequently follows specific needs for water rather than the desire for a general understanding of a hydrogeologic process or regime.  Recognition of this is important to preclude water resource misconceptions that perpetuate over time resulting from characterization objectives.  Early exploration of the water resources in the California desert focused on identifying watering sources for a hazardous travel area.  The Old Spanish Trail, an old trade route first described in an 1844 report by John C. Fremont, crossed the California desert following the course of springs and the Mojave River.  At the turn of the century, water research was conducted supporting mining interests, particularly the burgeoning borax trade by researchers including Bailey (1902).  This work was followed by the seminal compilation of Walter C. Mendenhall and his 1909 USGS publication “Some Desert Watering Places...” Subsequent work by Waring (1915) and others followed with more detailed reconnaissance activities with increasingly detailed information on flow and water quality.  More recently, extensive work has resulted in the area of the Death Valley Regional Groundwater Flow System from the proposed placement of the Yucca Mountain Nuclear Waste Repository. While the hydrogeologic investigations of Yucca Mountain that began in 1978 have resulted in substantial new understanding of the flow system within the northern Amargosa River Basin, the southern Amargosa Basin continued to have large data gaps since a detailed understanding was less important due to anticipated flow paths.  Recent hydrogeologic work conducted in the southern Amargosa Basin is evaluating the geology and geochemistry of springs feeding the designated Wild and Scenic reach of the Amargosa River, filling large gaps where little or no reconnaissance work has previously been conducted. This work is developing a new foundational understanding of the Amargosa River and water resources of the Amargosa Basin resetting historical misconceptions.


Andy Zdon, P.G., C.E.G., C.Hg. , Johnson Wright, Inc.

Andy Zdon is a Principal Hydrogeologist with more than 25 years of hydrogeological experience for Johnson Wright Inc. of Lafayette, California. He is a licensed geologist in California and Arizona, and is certified as both a hydrogeologist and engineering geologist in California. He has conducted numerous basin-wide and local hydrogeologic investigations in a wide range of environmental settings in California and Nevada. Zdon is currently conducting hydrologic investigations in the California portion of the Amargosa River Basin and is also known in the region for his book Desert Summits.