South Lahontan

Jet stream dynamics, hydroclimate, and fire in California from 1600 CE to present

National Academy of Sciences (NAS) | March 4th, 2019

Moisture delivery in California is largely regulated by the strength and position of the North Pacific jet stream (NPJ), winter high-altitude winds that influence regiona

Moisture delivery in California is largely regulated by the strength and position of the North Pacific jet stream (NPJ), winter high-altitude winds that influence regional hydroclimate and forest fire during the following warm season. We use climate model simulations and paleoclimate data to reconstruct winter NPJ characteristics back to 1571 CE to identify the influence of NPJ behavior on moisture and forest fire extremes in California before and during the more recent period of fire suppression. Maximum zonal NPJ velocity is lower and northward shifted and has a larger latitudinal spread during presuppression dry and high-fire extremes. Conversely, maximum zonal NPJ is higher and southward shifted, with narrower latitudinal spread during wet and low-fire extremes. These NPJ, precipitation, and fire associations hold across pre–20th-century socioecological fire regimes, including Native American burning, postcontact disruption and native population decline, and intensification of forest use during the later 19th century. Precipitation extremes and NPJ behavior remain linked in the 20th and 21st centuries, but fire extremes become uncoupled due to fire suppression after 1900. Simulated future conditions in California include more wet-season moisture as rain (and less as snow), a longer fire season, and higher temperatures, leading to drier fire-season conditions independent of 21st-century precipitation changes. Assuming continuation of current fire management practices, thermodynamic warming is expected to override the dynamical influence of the NPJ on climate–fire relationships controlling fire extremes in California. Recent widespread fires in California in association with wet extremes may be early evidence of this change.

Lake Lazarus: the strange rebirth of a Californian ecosystem

Nature Portfolio (Springer Nature) | November 12th, 2018

At the start of the twentieth century, Owens Lake in southern California was one of the largest inland bodies of water in the United States. By the mid-1920s, it was gone

At the start of the twentieth century, Owens Lake in southern California was one of the largest inland bodies of water in the United States. By the mid-1920s, it was gone, drained to provide water to a mushrooming Los Angeles. Over the past 30 years, the city has spent around US$2 billion to undo the damage. It has failed to restore the lake, but in The Spoils of Dust, Alexander Robinson describes how the effort has succeeded in another way: by creating a landscape no less valuable ecologically. By documenting the transitions the lake has undergone, he suggests a way forward for engineers, geologists, ecologists and landscape designers hoping to bring other environments back from the brink.

Land Subsidence in the Southwestern Mojave Desert, California, 1992–2009

U.S. Geological Survey (USGS) | July 8th, 2017

Groundwater has been the primary source of domestic, agricultural, and municipal water supplies in the southwestern Mojave Desert, California, since the early 1900s. Incr

Groundwater has been the primary source of domestic, agricultural, and municipal water supplies in the southwestern Mojave Desert, California, since the early 1900s. Increased demands on water supplies have caused groundwater-level declines of more than 100 feet (ft) in some areas of this desert (fig. 2 inset) between the 1950s and the 1990s (Stamos and others, 2001; Sneed and others, 2003). These water-level declines have caused the aquifer system to compact, resulting in land subsidence. Differential land subsidence (subsidence occurring at different rates across the landscape) can alter surface drainage routes and damage surface and subsurface infrastructure. For example, fissuring across State Route 247 at Lucerne Lake (fig. 2) has required repairs as has pipeline infrastructure near Troy Lake. Land subsidence within the Mojave River and Morongo Groundwater Basins of the southwestern Mojave Desert has been evaluated using InSAR, ground-based measurements, geology, and analyses of water levels between 1992 and 2009 (years in which InSAR data were collected). The results of the analyses were published in three USGS reports— Sneed and others (2003), Stamos and others (2007), and Solt and Sneed (2014). Results from the latter two reports were integrated with results from other USGS/ MWA cooperative groundwater studies into the broader scoped USGS Mojave Groundwater Resources Web site (http://ca.water.usgs.gov/mojave/). This fact sheet combines the detailed analyses from the three subsidence reports, distills them into a longer-term context, and provides an assessment of options for future monitoring.

LandFlex Grant Program Guidelines

California Department of Water Resources (DWR) | January 14th, 2023

The California Department of Water Resources (DWR) is administering the LandFlex Grant Program (LandFlex) through DWR’s Sustainable Groundwater Management (SGM) Grant P

The California Department of Water Resources (DWR) is administering the LandFlex Grant Program (LandFlex) through DWR’s Sustainable Groundwater Management (SGM) Grant Program. LandFlex (referred to as Ag Drought Relief) will award funds authorized by the California Budget Act of 2021 (Stats. 2021, ch. 44, § 25). This document contains DWR’s Guidelines and scoring criteria (Guidelines) for LandFlex. Climate change means that California needs to plan for a hotter, drier future. Long-term drought, fueled by climate change, has adversely affected the State’s water supplies, which includes groundwater availbility. In response to the Governor’s California’s Water Supply Strategy, Adapting to a Hotter, Drier Future, DWR will launch the LandFlex Program as a new and innovative tool to protect vulnerable drinking water wells. LandFlex will provide incentives to farmers to limit groundwater pumping in areas near communities reliant on vulnerable drinking water wells before they go dry. LandFlex combines traditional short-term fallowing incentives with the elimination of long-term unsustainable groundwater pumping, a unique approach to groundwater resilience. LandFlex is a program that will provide $25 million in block grants to local government agencies to grant to farmers who limit agricultural water use. Local government agencies will work directly with farmers in critically overdrafted (COD) basins (as identified in Bulletin 118) to identify lands that would reduce pumping impacts to nearby drinking water wells. Through financial incentives to farmers, LandFlex will provide multiple community benefits such as drinking water well relief, groundwater overdraft prevention, and climate resilience.

Landflex Grant Program Guidelines (revised)

California Department of Water Resources (DWR) | October 31st, 2024

Large closed-basin lakes sustainably supplied phosphate during the origins of life

American Association for the Advancement of Science (AAAS) | February 19th, 2025

The origin of life on Earth required a supply of phosphorus (P) for the synthesis of universal biomolecules. Closed lakes may have accumulated high P concentrations on ea

The origin of life on Earth required a supply of phosphorus (P) for the synthesis of universal biomolecules. Closed lakes may have accumulated high P concentrations on early Earth. However, it is not clear whether prebiotic P uptake in such settings would then have been sustainable. We show that large closed-basin lakes can combine high P concentrations at steady state with extremely high rates of biological productivity. Our case study is Mono Lake in California, which has close to 1 millimolar dissolved P at steady state despite extremely high rates of biological productivity, in contrast to smaller closed basins where life is scarce. Hence, large closed-basin lakes offer an environment where high rates of prebiotic P productivity can plausibly coexist with high steady-state P concentrations. Such lakes should have readily formed on the heavily cratered and volcanically active surface of early Earth.

Lessons from California’s 2012–2016 Drought

American Society of Civil Engineers (ASCE) | October 1st, 2018

California’s 5-year drought has ended, even as its aftermath lingers. From 2012–2016 much or all of California was under severe drought conditions, with gre

California’s 5-year drought has ended, even as its aftermath lingers. From 2012–2016 much or all of California was under severe drought conditions, with greatly diminished precipitation, snowpack, and streamflow and higher temperatures. Water shortages to forests, aquatic ecosystems, hydroelectric power plants, rural drinking water supplies, agriculture, and cities caused billions of dollars in economic losses, killed millions of forest trees, brought several fish species closer to extinction, and caused inconvenience and some expense to millions of households and businesses. The drought also brought innovations and improvements in water management, some of which will better prepare California for future droughts. This paper summarizes the magnitude and impacts of the 2012–2016 California drought. The paper then reviews innovations arising from the drought in the larger historical context of water management in California. Lessons for California and for modern drought management are then discussed. Droughts in modern, well-managed water systems serving globalized economies need not be economically catastrophic, but will always have impacts and challenges, particularly for native ecosystems. In California and every other water system, droughts usefully expose weaknesses and inadequate preparation in water management. In this regard for California, managers of ecosystems and small rural water supplies had the most to learn.

Letter in support of the Temporary Urgency Change Petition (TUCP)

California State Water Resources Control Board (SWRCB) | February 19th, 2023

Linked fire activity and climate whiplash in California during the early Holocene

Nature Portfolio (Springer Nature) | November 23rd, 2022

Recent wildfire activity in semi-arid regions like western North America exceeds the range of historical records. High-resolution paleoclimate archives such as stalagmi

Recent wildfire activity in semi-arid regions like western North America exceeds the range of historical records. High-resolution paleoclimate archives such as stalagmites could illuminate the link between hydroclimate, vegetation change, and fire activity in pre-anthropogenic climate states beyond the timescale of existing tree-ring records. Here we present an analysis of levoglucosan, a combustion-sensitive anhydrosugar, and lignin oxidation products (LOPs) in a stalagmite, reconstructing fire activity and vegetation composition in the California Coast Range across the 8.2 kyr event. Elevated levoglucosan concentrations suggest increased fire activity while altered LOP compositions indicate a shift toward more woody vegetation during the event. These changes are concurrent with increased hydroclimate volatility as shown by carbon and calcium isotope proxies. Together, these records suggest that climate whiplash (oscillations between extreme wetness and aridity) and fire activity in California, both projected to increase with anthropogenic climate change, were tightly coupled during the early Holocene.

Linking variation in water democracy to system performance on the human right to water

Springer Nature | October 8th, 2025