Lower Colorado River Basin Plan letter to the U.S. Bureau of Reclamation, 5/22/23

U.S. Bureau of Reclamation (USBR) | May 22nd, 2023

Lower Colorado River Mainstream Evaporation and Riparian Evapotranspiration Losses Report

U.S. Department of the Interior (DOI) | February 8th, 2024

On August 16, 2022, the Bureau of Reclamation (Reclamation) and Department of the Interior announced several administrative actions for consideration to improve and prote

On August 16, 2022, the Bureau of Reclamation (Reclamation) and Department of the Interior announced several administrative actions for consideration to improve and protect the long-term sustainability of the Colorado River System. The System is currently experiencing prolonged drought and low runoff conditions accelerated by climate change that have led to historically low water levels in Lakes Powell and Mead (Reclamation, 2021). One of the actions included reviewing and prioritizing additional administrative initiatives to address system losses in the lower Colorado River mainstream. As part of that action, this report provides an overview of historical mainstream evaporation and riparian evapotranspiration (ET) losses along the lower Colorado River and presents methodologies used to develop those datasets. This report does not make recommendations on how to account for system losses in the lower Colorado River mainstream. Supplemental documents: Appendix 1 – Reaches Identified in the Lower Colorado River Mainstream Evaporation and Riparian Evapotranspiration Losses Report Appendix 2 – LCRAS Open Water Monthly Evaporative Losses Appendix 3 – Lake Mead, Lake Mohave, and Lake Havasu Evaporation from Reclamation’s Hydrologic Database (HDB) Appendix 4 – LCRAS Riparian Monthly Evapotranspiration Losses by Vegetation Appendix 5 – Evaporation and Riparian Evapotranspiration (ET) Coefficients Appendix 6 – Evaporation and Riparian Evapotranspiration (ET) Rates

Maladaptation to drought: a case report from California, USA

Sustainability Science (Springer) | October 15th, 2015

The interactions between natural water availability and societal water demand and management are complex. In response to gaps in empirical research of the adaptive capaci

The interactions between natural water availability and societal water demand and management are complex. In response to gaps in empirical research of the adaptive capacity of social and environmental systems to climate stresses, we provide an assessment of responses to water scarcity during a multi-year drought in California. In particular, we use Barnett and O’Neill’s (Global Environ Change 20:211–213, 2010) criteria for maladaptation to examine responses in the agricultural and energy sectors to a multi-year (2007–2009) California drought. We conclude that despite evidence in both sectors of resiliency to the impacts of the drought, some of the coping strategies adopted increased the vulnerability of other systems. These other systems include California’s aquatic ecosystems and social groups that rely on those ecosystems for their health or employment; future generations whose resources were drawn down in the near-term, where otherwise those resources would have been available at a later time; and current and future generations who were, or will be, exposed to the effects of increased greenhouse gas emissions. This case study demonstrates that California’s current strategies for dealing with long or severe droughts are less successful than previously thought when short- and long-term impacts are evaluated together. This finding is particularly relevant given projections of more frequent and severe water shortages in the future due to climate change. This study recommends a shift from crisis-driven responses to the development and enactment of long-term mitigation measures that are anticipatory and focus on comprehensive risk reduction.

Management of the Colorado River: Water Allocations, Drought, and the Federal Role

Congressional Research Service (CRS) | August 4th, 2022

Management of the Colorado River: Water Allocations, Drought, and the Federal Role

Congressional Research Service (CRS) | September 7th, 2022

Managing California’s Freshwater Ecosystems: Lessons from the 2012–16 Drought

Public Policy Institute of California (PPIC) | November 9th, 2017

The 2012–16 drought caused unprecedented stress to California’s ecosystems and pushed many native species to the brink of extinction. It also tested the laws, policie

The 2012–16 drought caused unprecedented stress to California’s ecosystems and pushed many native species to the brink of extinction. It also tested the laws, policies, and institutions charged with protecting the environment. Eight case studies on environmental water management during the drought reveal both strengths and weaknesses in federal, state, and local response that can inform how California addresses future droughts.

Managing Drought in a Changing Climate: Four Essential Reforms

Public Policy Institute of California (PPIC) | September 12th, 2018

California’s climate is changing. Hotter temperatures, a shrinking snowpack, shorter and more intense wet seasons, rising sea level, and more volatile precipita

California’s climate is changing. Hotter temperatures, a shrinking snowpack, shorter and more intense wet seasons, rising sea level, and more volatile precipitation—with wetter wet years and drier dry years—are stressing the state’s water management system. Recent climate projections indicate that the pace of change will increase. To avoid unwanted social, economic, and environmental consequences, the water system will need to adapt to greater climate extremes and growing water scarcity. While California is making good progress in some areas of drought management, a more focused plan of action is needed. Successful adaptation will require strong leadership at the state and local levels, and cooperation on all fronts. The 2012–16 drought—the hottest in the state’s recorded history and one of the driest—offered a window into the future under a warming climate and lessons for managing future droughts. Using these lessons as a starting point, this report offers a road map of essential reforms to prepare for and respond to droughts in California’s changing climate. Key reforms include: Plan ahead. Stronger drought planning is critically important for urban water management, groundwater sustainability, safe drinking water in rural communities, and freshwater ecosystems. Upgrade the water grid. California needs a comprehensive program to address above- and below-ground storage, conveyance, and operational challenges by mid-century, including repairing facilities that are broken, expanding conveyance and storage capacity, and modernizing and integrating operations. Update water allocation rules. California should comprehensively update its water allocation governance. The goals should be to find equitable and efficient ways to allocate limited supplies among competing demands during dry times while promoting efforts to capture and store water during wet times. Find the money. Reliable funding is crucial for adapting to climate change. New sources are needed to pay for necessary water-management investments and to fill funding gaps in the state’s water system. The focus of this reform agenda is on drought, because drought―more than any other aspect of California’s climate―reveals the vulnerabilities of watermanagement systems. Importantly, these reforms will improve drought resilience for today’s conditions, not just for the future.

Managing Drought: Learning from Australia

Pacific Institute | February 1st, 2016

Overall, Australia survived the Millennium Drought, demonstrating world leading innovation and exceptional examples of water planning and management driven by crisis. Yet

Overall, Australia survived the Millennium Drought, demonstrating world leading innovation and exceptional examples of water planning and management driven by crisis. Yet there are also examples of missed opportunities, as well as initiatives and decisions that did not work well. The research presented here reflects on some of the key lessons from the Australian Millennium Drought experience in order to assess the opportunities for California. This report serves as a powerful resource for Californian water planners and managers as it grapples with drought and seeks to build resilient and sustainable water systems. It provides a one-stop shop overview of the key events and initiatives implemented in Australia’s four largest cities – Sydney, Melbourne, Brisbane (and the surrounding south east Queensland region), and Perth. The work represents one interpretation of the drought and responses, informed by significant engagement with utilities and governments throughout that period, and a close working knowledge of the water systems and the policy environment. Specific attention is given to the role of demand-side measures in reducing the impact of drought. In Australia, urban water efficiency was the quiet achiever – saving more water at lower cost and greater speed than supply options. California can benefit from long-term structural water savings by implementing water efficiency measures at a similar breadth and scale.

Managing Water for the Environment During Drought: Lessons from Victoria, Australia

Public Policy Institute of California (PPIC) | June 16th, 2016

Over the past 30 years the Australian state of Victoria developed innovative approaches to planning and setting priorities for environmental water, along with new tools t

Over the past 30 years the Australian state of Victoria developed innovative approaches to planning and setting priorities for environmental water, along with new tools to manage it. These sweeping reforms were in part a response to the Millennium Drought, a decade-long record dry spell that severely affected all water use in Victoria. California—currently in its fifth year of drought—has many similarities with Victoria, including significant challenges in managing the health of rivers and wetlands during times of extreme water scarcity. In this report, we examine the reforms enacted by Victoria and compare them to current environmental water management policies in California. This comparison highlights some key lessons learned by Victoria that may help guide how California adapts environmental water management to address future droughts. The environmental policy reforms enacted by Victoria were difficult and at times highly controversial. While it will take years to fully understand whether these reforms had their intended effect, there is no doubt that the state’s new approach to managing environmental water avoided some serious biological losses during the drought. Additionally, it is clear that the state is much better prepared for the next drought.

Mechanisms of a Meteorological Drought Onset: Summer 2020 to Spring 2021 in Southwestern North America

American Meteorological Society (AMS) | November 1st, 2022

By summer 2021 moderate to exceptional drought impacted 28% of North America, focused west of the Mississippi, with serious impacts on fire, water resources, and agricult

By summer 2021 moderate to exceptional drought impacted 28% of North America, focused west of the Mississippi, with serious impacts on fire, water resources, and agriculture. Here, using reanalyses and SST-forced climate models, we examine the onset and development of this southwestern drought from its inception in summer 2020 through winter and spring 2020/21. The drought severity in summer 2021 resulted from four consecutive prior seasons in which precipitation in the southwest United States was the lowest on record or, at least, extremely dry. The dry conditions in summer 2020 arose from internal atmospheric variability but are beyond the range of what the studied atmosphere models simulate for that season. From winter 2020 through spring 2021 the worsening drought conditions were guided by the development of a La Niña in the tropical Pacific Ocean. Decadal variability in the Pacific Ocean aided drought in the southern part of the region by driving the cool season to be drier during the last two decades. There is also evidence that the southern part of the region in spring is drying due to human-driven climate change. In sum the drought onset was driven by a combination of internal atmospheric variability and interannual climate variability and aided by natural decadal variability and human-driven climate change.