Water Resources Engineering (WRE) connects engineering hydrology and hydraulics with global, economic, environmental, and societal issues.Our student Samantha Steele makes this connection here…
The February 28th, 2013 article “Sahara Desert Dust Affects California Water Supply” was posted in the Los Angeles Times website online (http://articles.latimes.com/).  This news relates to the WRE domain of hydrology and specific issues of weather prediction and water supply planning.  This scientific study was inspired by two similar storms taking place in 2009 on the Sierra Nevada Mountains.  Both storms carried the same amount of water vapor, but one produced 40% more precipitation than the other.  Upon further investigation it was discovered that ground samples of the rain and snow, from the storm with more precipitation, showed an abundance of Asian dust.  A science team collected ground data in the Tahoe National Forest and simultaneously collected atmospheric samples from air measurements.  Data analysis showed that when dust and biological particles are present, above the Sierra peaks, there was more precipitation.  This is the first study to directly document that dust from as far away as the Sahara, Taklimakan and Gobi deserts can create substantially more precipitation in the Western United States.  The windblown material is acting as a seed for atmospheric ice, which is forming a large amount of precipitation.  This research was part of a three year field study called CalWater, investigating the influences on California rain and snow.  This news article has scientific merit and calls on known meteorological facts.  Jay Hardy comments on the concept of ice nuclei in his article titled, “Microbial Showers…The Rain-Making Bacteria”, mentioning that bacteria as well as dust and soot can serve as the seeds around which ice is formed.  He goes on to describe how water molecules attach to the crystals making them increasingly larger until they fall to the ground as rain or snow.  After finding numerous news sources reflecting the same information, (including but not limited to: Climate Central, The Earth System Research Laboratory, University of California, San Diego News Office and the Associated Press), I am confident that this story accurately represents WRE facts.  After reflection on this article I believe it left out some critical implications of the precipitation increase.  It noted Guido Franco’s comment that “It may counteract some of the effects of a warming climate”, but I would consider that a quite optimistic and ignoring the potential harmful effects of this weather phenomena.
Water resources engineering is an interdisciplinary field, in which hydrologic and hydraulic systems are designed and managed in order to maximize the potential benefits and minimize the adverse impacts that could occur to any global, economic, environmental or societal issue.  This particular article has implications in global and economic contexts.  This story reflects the need for global weather pattern analysis in order to address the adverse effects that can take place on a local community from stimuli introduced halfway across the world.  The economic implications can be extremely devastating if all of the water storage facilities need to be re-designed for the unforeseen increase in precipitation, or it could create a temporary monetary alleviation to residents of California who have historically had problems with water supply.  An article by Lauren Morello published February 28th, 2013 explains that the Sierra Nevada provides one-third of California’s water and generates about 15 percent of the state’s electricity hydropower.  As increasing amounts of precipitation fall in the Sierra Nevada Mountains, the design and management of water storage and water supply facilities need to be adapted.  In closing, this WRE issue has numerous effects within context area of the Sierra Nevada and all of California, but can also affect other western mountainous regions in the United States, or under similar circumstances around the globe.


This graphic shows the path of aerosols that reached California in 2011. Circled numbers indicate locations in which dust was captured in CALIPSO satellite images.


Frank Gehrke, chief snow surveyor for the California Department of Water Resources, takes a snow measurement at Phillips Station in the Sierras (photo: Brant Ward, San Francisco Chronicle)

Works Cited

Boxall, B. (2013, February 28). Sahara Desert dust afftects California Water Supply. Retrieved April 9, 2013, from Los Angeles Times: http://articles.latimes.com/2013/feb/28/local/la-me-water-dust-20130301

Broder, K. (2013, March 5). Scientists Find Asian, African Dust Afftects California Snowfall and Water Supply. Retrieved April 9, 2013, from All Gov California: http://www.allgov.com/usa/ca/news/unusual-news/scientists-find-asian-african-dust-affects-california-snowfall-and-water-supply-130305?news=847258

Hardy, J. (2012). Microbial Showers…The Rain-Making Bacteria. Retrieved April 9, 2013, from Hardy Diagnostics: http://www.hardydiagnostics.com/articles/Ice-Forming-Bacteria.pdf

Morello, L. (2013, February 28). Dusty Spring in Asia, Africa Can Inrease Snow in California. Retrieved April 9, 2013, from Climate Central: http://www.climatecentral.org/news/african-asian-dust-influences-snow-in-california-study-finds-15665