Strum Und Drand – California’s Remarkable Storm-Drought Connection

International Association for Hydro-Environment Engineering and Research | May 31st, 2019

Storm and drought are essentially the whole story of water and life in California in ways that have always made hydro-environmental engineering a unique proposition th

Storm and drought are essentially the whole story of water and life in California in ways that have always made hydro-environmental engineering a unique proposition there. To begin with, California experiences larger year-to-year variations in precipitation than elsewhere in the US, with standard deviations of annual precipitation between 30-50% of long-term averages, compared to 10-30% nearly everywhere else. California’s annual precipitation totals routinely vary from as little as 50% to more than 200% of long-term averages, with those dry excursions forming our droughts. This extreme variability arises because California’s Mediterranean climate only provides a limited seasonal window of precipitation events, and within that period a small number of storms deliver most of the State’s precipitation each year. If a few extra large storms reach California in a given winter, we can have a very wet year indeed; if some are lacking, we face drought. But the storm-drought connection is deeper and more pervasive in California than anywhere else in the US.

Study role of climate change in extreme threats to water quality

Nature Portfolio (Springer Nature) | July 21st, 2016

With concerns about climate ‘extremes’ growing, water is often the focus — either too much or too little. That is no coincidence: climate and the hydrolog

With concerns about climate ‘extremes’ growing, water is often the focus — either too much or too little. That is no coincidence: climate and the hydrological cycle are tightly coupled, and water is essential to ecosystems and societies. But it is not just the quantity of water that matters. So does its quality.

Summary of Climate Change Impacts to Water and Sanitation for Frontline Communities in the United States: Water, Sanitation, and Climate Change in the United States Part 1

Pacific Institute | December 6th, 2023

Climate change is among the most urgent, wide-ranging crises we face. It poses significant challenges and is already resulting in severe impacts to drinking water and san

Climate change is among the most urgent, wide-ranging crises we face. It poses significant challenges and is already resulting in severe impacts to drinking water and sanitation access—both for those currently living without access and for communities where forces like drought, flooding, sea-level rise, wildfires, and intensifying storms threaten to degrade or strip basic services from the people. Access to sufficient, safe, acceptable, physically accessible, and affordable water and sanitation is essential for human health and wellbeing, as well as economic prosperity—and climate change will inevitably make ensuring all have access more challenging. Without water and sanitation access, people do not have water to drink, cannot clean, shower, or wash their hands, and cannot safely dispose of human waste. They may have to travel long distances to purchase and haul water back to their homes. Without access to water, they also have less ability to cool their homes, protect themselves from wildfires, and work or go to school. An economic assessment by DigDeep found that for every household in the United States without access to water and sanitation, the domestic economy loses $15,800 annually in extra health care costs, time and money spent on bottled water, lost educational or work opportunities, and premature death (DigDeep 2022). (Click here for Part 2)

Sustainable Management of a Water Reservoir System Facing Climate Uncertainty

Social Science Research Network (SSRN) | November 27th, 2024

Water scarcity is a growing global issue. It affects even highly developed regions like California, the world's fifth largest economy, where years of severe droughts inte

Water scarcity is a growing global issue. It affects even highly developed regions like California, the world's fifth largest economy, where years of severe droughts interspersed with unusually wet seasons have caused societal debates over the management of the water resources stored in the state's extensive reservoir system. This paper presents a strategic optimization model for the long-term, sustainable management of such a system. Introducing a new modeling paradigm based on cycles of stochastic length, defined by the event when all reservoirs are simultaneously full, we avoid the limitations of traditional models and obtain sustainable management policies. To address the unpredictable effect of climate change on future water supply, we adopt a distributionally robust framework where nature chooses adverse inflow distributions. This leads to a stochastic shortest path problem under distributional ambiguity. Using tools from stochastic dynamic programming and aggregation methods, we obtain policy insights and overcome the curse of dimensionality typically associated with systems models. In a case study for California's Sacramento River Basin, we report suboptimality gaps between 3% and 15%, with our sustainable management policy reducing average cycle shortage costs by 40% compared to the current policy, demonstrating the significant cost saving potential.

Sycamore Alluvial Woodland Planting Guide

San Francisco Estuary Institute (SFEI) | August 1st, 2018

This memo builds on recent field-based studies which examined the relative distribution, health, and regeneration patterns of two major stands of sycamore alluvial woodla

This memo builds on recent field-based studies which examined the relative distribution, health, and regeneration patterns of two major stands of sycamore alluvial woodland (SAW) in Santa Clara County. Given that the acquisition, restoration, and improved management of SAW is mandated as part of the Santa Clara Valley Habitat Plan (VHP), it is increasingly critical to understand how, when, and where sycamores establish, which is critical for successful restoration design and planting success. This memo is meant to summarize recent studies on habitat requirements of the SAW habitat type, and present a planting plan and monitoring framework for restoring SAW habitat at two sites in Santa Clara County. As the science and restoration of SAW is an ongoing topic of interest, we also suggest possible subsequent studies needed to further sycamore restoration goals. 

Synergies between climate anomalies and hydrological modifications facilitate estuarine biotic invasions

Ecology Letters (Wiley) | June 6th, 2011

Environmental perturbation, climate change and international commerce are important drivers for biological invasions. Climate anomalies can further increase levels of hab

Environmental perturbation, climate change and international commerce are important drivers for biological invasions. Climate anomalies can further increase levels of habitat disturbance and act synergistically to elevate invasion risk. Herein, we use a historical data set from the upper San Francisco Estuary to provide the first empirical evidence for facilitation of invasions by climate extremes. Invasive zooplankton species did not become established in this estuary until the 1970s when increasing propagule pressure from Asia coincided with extended drought periods. Hydrological management exacerbated the effects of post‐1960 droughts and reduced freshwater inflow even further, increasing drought severity and allowing unusually extreme salinity intrusions. Native zooplankton experienced unprecedented conditions of high salinity and intensified benthic grazing, and life history attributes of invasive zooplankton were advantageous enough during droughts to outcompete native species and colonise the system. Extreme climatic events can therefore act synergistically with environmental perturbation to facilitate the establishment of invasive species.

Taming wildfires in the context of climate change: The case of the United States

Organisation for Economic Co-operation and Development (OECD) | January 22nd, 2024

Shifts in climate cycles (e.g., Pacific Decadal Oscillation, El Niño-Southern Oscillation), combined with ongoing changes in drought, temperature and snowmelt, together,

Shifts in climate cycles (e.g., Pacific Decadal Oscillation, El Niño-Southern Oscillation), combined with ongoing changes in drought, temperature and snowmelt, together, have contributed to the overall warmer, drier conditions that fuel extreme wildfires (Environmental Protection Agency, 2022[4]; Kitzberger et al., 2007[10]; Westerling, 2016[11]). The period with the largest increase in area burned coincides with many of the warmest years on record nationwide (Environmental Protection Agency, 2022[4]). Such changes are especially visible in the western United States, where the peak extent of area burned now occurs about one month earlier than just two decades ago. Other factors including longer dry seasons and drier soils and vegetation are increasingly creating the conditions for catastrophic wildfires (Environmental Protection Agency, 2022[4]; US Global Change Research Program, 2018[9]). Wildfires are also further spreading into areas historically unaccustomed to fire, including high elevation areas in the west of the country (Figure 1.2) (OECD, 2023[2]; Alizadeh et al., 2021[12]), which may be less prepared for wildfires and potentially harmed by its impacts.

Targeting climate diversity in conservation planning to build resilience to climate change

Ecological Society of America (Wiley) | April 24th, 2015

Climate change is raising challenging concerns for systematic conservation planning. Are methods based on the current spatial patterns of biodiversity effective g

Climate change is raising challenging concerns for systematic conservation planning. Are methods based on the current spatial patterns of biodiversity effective given long-term climate change? Some conservation scientists argue that planning should focus on protecting the abiotic diversity in the landscape, which drives patterns of biological diversity, rather than focusing on the distribution of focal species, which shift in response to climate change. Climate is one important abiotic driver of biodiversity patterns, as different climates host different biological communities and genetic pools. We propose conservation networks that capture the full range of climatic diversity in a region will improve the resilience of biotic communities to climate change compared to networks that do not. In this study we used historical and future hydro-climate projections from the high resolution Basin Characterization Model to explore the utility of directly targeting climatic diversity in planning. Using the spatial planning tool, Marxan, we designed conservation networks to capture the diversity of climate types, at the regional and sub-regional scale, and compared them to networks we designed to capture the diversity of vegetation types. By focusing on the Conservation Lands Network (CLN) of the San Francisco Bay Area as a real- world case study, we compared the potential resilience of networks by examining two factors: the range of climate space captured, and climatic stability to 18 future climates, reflecting different emission scenarios and global climate models. We found that the climate-based network planned at the sub-regional scale captured a greater range of climate space and showed higher climatic stability than the vegetation and regional based-networks. At the same time, differences among network scenarios are small relative to the variance in climate stability across global climate models. Across different projected futures, topographically heterogeneous areas consistently show greater climate stability than homogenous areas. The analysis suggests that utilizing high-resolution climate and hydrological data in conservation planning improves the likely resilience of biodiversity to climate change. We used these analyses to suggest new conservation priorities for the San Francisco Bay Area.

Technical Guidance for Incorporating Climate Change Information into Water Resources Planning Studies

U.S. Bureau of Reclamation (USBR) | ?

The impacts of climate change are being felt across the Western United States. Warming is affecting water supplies by changing the overall annual volume of precipitation

The impacts of climate change are being felt across the Western United States. Warming is affecting water supplies by changing the overall annual volume of precipitation and altering the balance of rain versus snowfall. Communities are facing increasing problems with water availability and drought, flooding, and increased risk of forest fires. The requirements established by Secretarial Order 3289, Departmental Manual 523 DM 1, Executive Order 13653, and Reclamation’s Directives and Standards CMP 09-02 for feasibility studies reinforces the need for Reclamation's on-going programs to be more resilient to the impacts of climate change and for continued efforts to incorporate climate change information into aspects of our mission where it has not been fully considered in the past such as in decisions regarding ecosystem restoration, reservoir operations, infrastructure investments and planning capacity. This document is an important step to reinforcing Reclamation’s planning capacity by providing guidance to help study teams navigate the range of planning and technical methods available to account for climate change impacts in feasibility studies. The effects of climate change have altered and will continue to alter the basic assumptions underlying Reclamation’s water resources planning. Effective water management and planning rely on an understanding of climate change impacts on water supply, demand, and criteria that govern or guide water management. The guidance in this document may also be applied to environmental compliance studies since they are typically conducted concurrently with feasibility studies. The guidance is organized around the planning and technical framework for conducting a feasibility study as detailed in CMP 09-02, and which occurs in two phases: the scoping phase and the alternative formulation and evaluation phase.

The 1922 Compact is Now the Obvious Elephant in the Negotiating Room

John Fleck | October 6th, 2025