North Lahontan

Advances in Sub-seasonal to Seasonal Prediction Relevant to Water Management in the Western United States

American Meteorological Society (AMS) | July 21st, 2022

Water management in the semi-arid western United States (U.S.) is a challenging endeavor that evolves from year to year based on large-scale atmospheric and oceanic condi

Water management in the semi-arid western United States (U.S.) is a challenging endeavor that evolves from year to year based on large-scale atmospheric and oceanic conditions. This region has frequently experienced prolonged periods of drought with substantial socioeconomic impacts; the most recent instance involves California entering its third consecutive drought year. As context for the economic implications of drought, California’s enacted state budget for the Fiscal Year 2021-22 authorizes more than $600 million for the California Department of Water Resources for providing immediate drought support to local water agencies (CA State Budget 2021a); this amount is part of a package of more than $5 billion over four years for water resilience and drought preparedness (CA State Budget 2021b). For drought preparedness, state and local water managers would like to rely on skillful forecasts on timescales that span the spectrum between weather forecasts and climate predictions. Despite recent improvements in developing sub-seasonal (2- to 6-weeks lead) and seasonal (2- to 6-months lead) prediction systems that compete with and/or outperform existing dynamical and statistical models (e.g., Gibson et al. 2021, Switanek et al. 2020, DeFlorio et al. 2019), forecasting limitations have hindered crucial management decisions for western U.S. water managers, especially related to longer-lead planning, budgeting, resource allocation, and better preparedness for wet and dry extremes (DeFlorio et al. 2021). Improved understanding of physical phenomena and processes governing weather and climate extremes and utilization of emerging forecast methodologies are critical to developing skillful S2S forecast products relevant to water management.

Advancing Strategic Land Repurposing and Groundwater Sustainability in California

Environmental Defense Fund (EDF) | March 26th, 2021

For decades, California has been on a steady trajectory toward water scarcity, which is now exacerbated by climate change. More frequent and intense droughts and incre

For decades, California has been on a steady trajectory toward water scarcity, which is now exacerbated by climate change. More frequent and intense droughts and increased demands have affected the reliability of surface water supplies. As a result, many have looked to groundwater to fill the gap. Groundwater overpumping has resulted in adverse impacts such as reduction in groundwater storage, subsidence, water quality degradation, sea water intrusion, wells going dry and depletion of interconnected surface waters throughout many areas in California’s San Joaquin Valley. These impacts led to the passage of the Sustainable Groundwater Management Act (SGMA) by the state Legislature in 2014, which mandates sustainable use of groundwater by 2040 for the most critically overdrafted basins.

Agricultural risks from changing snowmelt

Nature Portfolio (Springer Nature) | April 20th, 2020

Snowpack stores cold-season precipitation to meet warm-season water demand. Climate change threatens to disturb this balance by altering the fraction of precipita

Snowpack stores cold-season precipitation to meet warm-season water demand. Climate change threatens to disturb this balance by altering the fraction of precipitation falling as snow and the timing of snowmelt, which may have profound effects on food production in basins where irrigated agriculture relies heavily on snowmelt runoff. Here, we analyse global patterns of snowmelt and agricultural water uses to identify regions and crops that are most dependent on snowmelt water resources. We find hotspots primarily in high-mountain Asia (the Tibetan Plateau), Central Asia, western Russia, western US and the southern Andes. Using projections of sub-annual runoff under warming scenarios, we identify the basins most at risk from changing snowmelt patterns, where up to 40% of irrigation demand must be met by new alternative water supplies under a 4 °C warming scenario. Our results highlight basins and crops where adaptation of water management and agricultural systems may be especially critical in a changing climate.

An Assessment of Urban Water Demand Forecasts in California

Pacific Institute | August 5th, 2020

In California, urban per capita water demand has declined dramatically over the past several decades, driven in part by greater uptake of water-efficient devices. These r

In California, urban per capita water demand has declined dramatically over the past several decades, driven in part by greater uptake of water-efficient devices. These reductions have important implications for estimating future water demand. However, failure to account for the long-term trend of declining per capita water demand has led to routine overestimation of future water demand. This can lead to unnecessary and costly investment in unneeded infrastructure and new sources of supply, higher costs, and adverse environmental impacts. This report examines the accuracy of long-range water demand forecasts for California’s 10 largest urban water suppliers. It finds that per capita water demand declined for all water suppliers between 2000 and 2015. In most cases, reductions in per capita water demand were so large that total water demand declined during this period. Additionally, all water suppliers overestimated demand, driven largely by inflated estimates of per capita water demand and, to a lesser extent, overestimates of population growth rates. The report offers recommendations on how to improve the accuracy of long-range water demand forecasts.

An Evolutionary Theory of Administrative Law

Southern Methodist University | May 25th, 2018

Law evolves to accommodate change—this is axiomatic in most academic legal traditions. But in the era of the administrative state, with congressional gridlock and a jud

Law evolves to accommodate change—this is axiomatic in most academic legal traditions. But in the era of the administrative state, with congressional gridlock and a judiciary hesitant to address policy questions, evolution of statutory law has become much more difficult. This leads to pent up demand for change in legal regimes. If the legislature and the courts cannot provide an outlet for this pressure, where does it go? How does the law continue to change? Although other scholars have looked to agencies as engines of legal change, we lack a theoretical framework to understand how that change happens. I argue that an evolutionary framework provides an informative framework for understanding administrative legal change. I provide three case studies that demonstrate the administrative evolution of the Endangered Species Act. In spite of tremendous advances in conservation, fundamental changes in scientists’ understanding of human impacts on the natural world, and increasingly strident clashes over private property rights and endangered species, the Act has remained largely unchanged for the last 35 years. In a functioning legislative system, the Act would have been amended to accommodate many of these changes. Instead, the case studies show a mechanism of legal change through agency action analogous to the mechanisms underlying biological evolution. Other commentators have argued the administrative state stymies evolution of the law, but this research contradicts that view. Applying an evolutionary framework to administrative actions creates a new theory of administrative evolution of the law, placing administrative analysis within the long tradition of evolutionary approaches to legal change used by commentators from Aristotle to Holmes. In contrast to traditional normative theories of administrative law, an evolutionary approach focuses on how change progresses over time. This theory of administrative evolution of the law also casts new light on a host of normative questions, from the role of judicial review to improvements in agency decision-making. Considering administrative actions within the broader context of the legal evolution promises a fruitful new approach to analyzing administrative law.

Anthropogenic warming impacts on California snowpack during drought

American Geophysical Union (AGU) | March 15th, 2017

Sierra Nevada climate and snowpack is simulated during the period of extreme drought from 2011 to 2015 and compared to an identical simulation except for the removal of t

Sierra Nevada climate and snowpack is simulated during the period of extreme drought from 2011 to 2015 and compared to an identical simulation except for the removal of the twentieth century anthropogenic warming. Anthropogenic warming reduced average snowpack levels by 25%, with middle‐to‐low elevations experiencing reductions between 26 and 43%. In terms of event frequency, return periods associated with anomalies in 4 year 1 April snow water equivalent are estimated to have doubled, and possibly quadrupled, due to past warming. We also estimate effects of future anthropogenic warmth on snowpack during a drought similar to that of 2011–2015. Further snowpack declines of 60–85% are expected, depending on emissions scenario. The return periods associated with future snowpack levels are estimated to range from millennia to much longer. Therefore, past human emissions of greenhouse gases are already negatively impacting statewide water resources during drought, and much more severe impacts are likely to be inevitable.

Anthropogenic Warming Impacts on Today's Sierra Nevada Snowpack and Flood Risk

American Geophysical Union (AGU) | June 15th, 2018

This study investigates temperature impacts to snowpack and runoff‐driven flood risk over the Sierra Nevada during the extremely wet year of 2016–2017, which followed

This study investigates temperature impacts to snowpack and runoff‐driven flood risk over the Sierra Nevada during the extremely wet year of 2016–2017, which followed the extraordinary California drought of 2011–2015. By perturbing near‐surface temperatures from a 9‐km dynamically downscaled simulation, a series of offline land surface model experiments explore how Sierra Nevada hydrology has already been impacted by historical anthropogenic warming and how these impacts evolve under future warming scenarios. Results show that historical warming reduced 2016–2017 Sierra Nevada snow water equivalent by 20% while increasing early‐season runoff by 30%. An additional one third to two thirds loss of snowpack is projected by the end of the century, depending on the emission scenario, with middle elevations experiencing the most significant declines. Notably, the number of days in the future with runoff exceeding 20 mm nearly doubles under a mitigation emission scenarios and triples under a business‐as‐usual scenario. A smaller snow‐to‐rain ratio, as opposed to increased snowmelt, is found to be the primary mechanism of temperature impacts to Sierra snowpack and runoff. These findings are consequential to the prevalence of early‐season floods in the Sierra Nevada. In the Feather River Watershed, historical warming increased runoff by over one third during the period of heaviest precipitation in February 2017. This suggests that historical anthropogenic warming may have exacerbated runoff conditions underlying the Oroville Dam spillway overflow that occurred in this month. As warming continues in the future, the potential for runoff‐based flood risk may rise even higher.

Arsenic in California Drinking Water

Environmental Integrity Project | September 15th, 2016

More than three years after the U.S. Environmental Protection Agency found California in noncompliance with the federal Safe Drinking Water Act, 95 community water system

More than three years after the U.S. Environmental Protection Agency found California in noncompliance with the federal Safe Drinking Water Act, 95 community water systems in the state, serving more than 55,000 people, are still providing water with illegal levels of arsenic, according to an examination of state data for the last two years. Arsenic occurs naturally in the soil and groundwater in parts of California and is a known carcinogen that may also damage the developing brains of children and cause other health problems. Many of the people drinking excessive levels of arsenic are poor and/or Latino or African- American, with a cluster in the San Joaquin Valley. Nearly all have been exposed to excessive arsenic levels for at least five years and probably longer.

Assembly Bill 1337

State of California Office of Legislative Counsel | February 16th, 2023

Assembly Bill No. 2108, Chapter 347, An act to add Sections 189.7 and 13149.2 to the Water Code, relating to water

State of California Office of Legislative Counsel | September 16th, 2022