How unusual is the 2012–2014 California drought?

American Geophysical Union (AGU) | December 30th, 2014

For the past three years (2012–2014), California has experienced the most severe drought conditions in its last century. But how unusual is this event? Here we use two

For the past three years (2012–2014), California has experienced the most severe drought conditions in its last century. But how unusual is this event? Here we use two paleoclimate reconstructions of drought and precipitation for Central and Southern California to place this current event in the context of the last millennium. We demonstrate that while 3 year periods of persistent below-average soil moisture are not uncommon, the current event is the most severe drought in the last 1200 years, with single year (2014) and accumulated moisture deficits worse than any previous continuous span of dry years. Tree ring chronologies extended through the 2014 growing season reveal that precipitation during the drought has been anomalously low but not outside the range of natural variability. The current California drought is exceptionally severe in the context of at least the last millennium and is driven by reduced though not unprecedented precipitation and record high temperatures.

Hydro-Electric Development in California

Scientific American | August 2nd, 1913

A glance at a map of California similar to that accompanying this article, on which is portrayed the veritable network of long-distance transmission lines that mark th

A glance at a map of California similar to that accompanying this article, on which is portrayed the veritable network of long-distance transmission lines that mark the course of hydro-electric development from end to end of the State, might convey to one not acquainted with actual conditions, the impression that there is but little left undeveloped of the sources of water-power with which this wonderland of the West abounded when first adventurous man started out in his now far-reaching enterprise among the head-waters of our mountain streams. This impression has, indeed, been circulated widely by those who in pursuit of a. policy of so-called conservation would hinder the development of California/s natural resources, and so, her progress and advancement. What foundation it has in fact may be gathered from certain statistics to hand. Mr. M.O. Leighton, Chief Hydrographer of the United States Geological Survey at Washington, in an article on “Water-power in the United States," published in the May number, 1909, of the Annals of the American Academy of Political and Social Science, writes: “The “water power plants in the United States make productive use of only 5,500,000 horse-power, less than one fortieth of that ultimately available.” The report of the United States Geological Survey upon California, published March, 1912, gives the following figures for our State: Potential horse-power development on a basis of 90 per cent efiiciency; minimum 4,109,000, estimated maximum 9,382,000; on a basis of 75 per cent efficiency, minimum 3,424,000, estimated maximum 7,818,000.

Hydroclimate response of spring ecosystems to a two‐stage Younger Dryas event in western North America

Nature Portfolio (Springer Nature) | May 5th, 2022

The Younger Dryas (YD) climate event is the preeminent example of abrupt climate change in the recent geologic past. Climate conditions during the YD were spatially compl

The Younger Dryas (YD) climate event is the preeminent example of abrupt climate change in the recent geologic past. Climate conditions during the YD were spatially complex, and high-resolution sediment cores in the North Atlantic, western Europe, and East Asia have revealed it unfolded in two distinct stages, including an initial stable climatic period between ~ 12.9 and 12.2 ka associated with a weakened Atlantic Meridional Overturning Circulation (AMOC) and a second phase characterized by variable conditions until 11.7 ka as the AMOC recovered. Decades of investigations into the climate of western North America during the YD have failed to identify this stepped phenomenon. Here we present hydroclimate data from paleospring deposits in Death Valley National Park (California, USA) that demonstrate unequivocal evidence of two-stage partitioning within the YD event. High groundwater levels supported persistent and long-lived spring ecosystems between ~ 13.0 and 12.2 ka, which were immediately replaced by alternating wet and dry environments until ~ 11.8 ka. These results establish the mid-YD climate transition extended into western North America at approximately the same time it was recorded by hydrologic systems elsewhere in the Northern Hemisphere and show that even short-lived changes in the AMOC can have profound consequences for ecosystems worldwide.

Hydrogeology of the Sutter Basin, Sacramento Valley, California

University of Arizona | March 23rd, 1971

A mound of saline water exists in continental sediments between two fresh water rivers in the Sutter Basin of the Sacramento Valley, California. This saline water has mov

A mound of saline water exists in continental sediments between two fresh water rivers in the Sutter Basin of the Sacramento Valley, California. This saline water has moved from the marine sediments, at depth, upward along the Sutter Basin Fault and then through 2,000 feet of alluvium.

Impacts of the California Drought from 2007 to 2009: Surprising Outcomes for California’s Agriculture, Energy, and Environment

Pacific Institute | June 16th, 2011

California’s three-year drought, which ended with this season’s cool and wet weather, had complicated and serious impacts that have been poorly understood and reporte

California’s three-year drought, which ended with this season’s cool and wet weather, had complicated and serious impacts that have been poorly understood and reported. Some of the impacts were expected; others were surprising. The Pacific Institute has just completed a nine-month assessment of new data from California’s agricultural, energy, and environmental sectors to evaluate actual consequences of the drought for the state. Analysis of state and federal data released over the past year finds that contrary to much of the media reporting, California’s agricultural community proved flexible and resilient, generating agri­cultural revenues in 2007, 2008, and 2009 that were the highest on record. And agriculture-related occupations remained a stable portion of total jobs available in areas directly impacted by water supply restrictions. Less frequently reported were the substantial impacts on energy production and aquatic ecosystems during the drought, which were economically and environmentally significant. “More severe drought is inevitable, and the U.S. – and California in particular – has not reformed drought monitoring, evaluation, planning, and response strategies the way other countries and regions have,” said Juliet Christian-Smith, senior research associate at the Pacific Institute and lead author of the report. “To become more resilient to future droughts, it will be critical to shift from crisis-driven responses to long-term mitigation strategies.” The Pacific Institute analysis, Impacts of the California Drought from 2007-2009, focused on three drought-sensitive sectors: agricultural production, energy production, and ecosystem health.  

Irrigation

Scientific American | January 17th, 1903

Irrigation in California

Scientific American | January 4th, 1890

Is climate change implicated in the 2013-2014 California drought? A hydrologic perspective

American Geophysical Union (AGU) | April 21st, 2015

California has experienced severe drought in 2012–2014 (which appears to be continuing into 2015), with especially low winter precipitation and mountain snowpack in wi

California has experienced severe drought in 2012–2014 (which appears to be continuing into 2015), with especially low winter precipitation and mountain snowpack in winter 2013–2014. However, the extent to which climate change is implicated in the drought, if at all, is not clear. By applying modeling and statistical approaches, we construct a historical record of California snowpack, runoff, and other hydrological variables of almost 100 years in length and use the reconstructed records to analyze climate trends in the Sierra Nevada and their impact on extreme drought events in the historic record. We confirm a general warming trend and associated decreasing trends in spring snowpack and runoff. We find that the warming may have slightly exacerbated some extreme events (including the 2013–2014 drought and the 1976–1977 drought of record), but the effect is modest; instead, these drought events are mainly the result of variability in precipitation.

Joshua Tree National Park: A History of Preserving the Desert

National Park Service (NPS) | March 16th, 2015

Landscape Patterns and Processes of the McCormack-Williamson Tract and Surrounding Area: A framework for restoring a resilient and functional landscape

San Francisco Estuary Institute (SFEI) | March 25th, 2013

This report uses a reconstruction of the historical (early 19th century) Sacramento-San Joaquin Delta landscape in concert with contemporary data to elucidate restoration

This report uses a reconstruction of the historical (early 19th century) Sacramento-San Joaquin Delta landscape in concert with contemporary data to elucidate restoration opportunities and constraints at the McCormack-Williamson Tract and within the surrounding Delta setting. Historical ecology encourages a landscape-level perspective of restoration through improved understanding of how physical processes created and maintained habitat mosaics in the recent past. This perception of landscapes can be used to evaluate current conditions and develop future restoration scenarios. We used the recently completed study of the historical Delta landscape (Whipple et al. 2012) to explore opportunities for the McCormack-Williamson Tract (MWT), a 1,645 acre (6.6 km2) tract along the Mokelumne River (Figure 1 and Figure 2). This site exemplifies the need to balance contemporary constraints to restoration (including existing infrastructure and flood protection concerns) with the goals of landscape-scale restoration. To explore some of the strategies and opportunities available to advance the landscape-scale restoration in the MWT area, three general concepts emerged: increasing landscape complexity, connectivity, and resilience. To understand how to interpret and improve these attributes, we developed conceptual models that placed the site within the larger landscapes of the historical Delta, relating local habitat features to regional controlling physical gradients. This aided interpretation of the contemporary physical landscape and allowed identification of opportunities and constraints to both short-term and long-term landscape-scale restoration. The historical record reveals features such as floodplain lakes, forests on natural river levees, and tidal channels in the study area. These and other features could be strategically incorporated into a restoration vision, or an “operational landscape unit” for this part of the Delta (Verhoeven et al. 2008). This type of perspective can help focus restoration targets, including the relative proportion and placement of different habitat types and landscape elements within project design constraints, maximizing the site’s ecological potential. The landscape-scale approach also identifies opportunities to improve ecological connectivity and long-term adaptability to sea level rise and other environmental changes. Some of these opportunities may be critical to the ecological function and resilience of the area, but may not be able to be addressed in the immediate MWT project design. Thus, a central component of translating a historical landscape perspective to site-scale design is envisioning an adaptable restoration process that spans short-term restoration actions that are possible within the site’s bounds, while maintaining a longer-term vision of what is needed at the landscape scale.