San Joaquin Basin Flood‑MAR Watershed Studies Basin-wide Summary and Next Steps

California Department of Water Resources (DWR) | December 3rd, 2025

The San Joaquin Basin Flood‑MAR Watershed Studies (Watershed Studies) — comprising five watershed reports for Calaveras, Stanislaus, Tuolumne, Merced and Upper San Jo

The San Joaquin Basin Flood‑MAR Watershed Studies (Watershed Studies) — comprising five watershed reports for Calaveras, Stanislaus, Tuolumne, Merced and Upper San Joaquin watersheds and a Basinwide Summary — deliver data-driven assessments of climate change vulnerabilities and adaptation that reveal risks and consequences and call for bold, coordinated solutions. In the San Joaquin Basin, the effects of climate change will exacerbate long-standing water management challenges. As these reports quantify, every water management sector — flood, water supply (surface and groundwater), and ecosystems — is vulnerable. Without bold action, the basin and its watersheds face mounting threats to communities, economies, and ecosystems. Although each watershed has unique characteristics, all confront a future climate that is hotter and characterized by more extreme weather. For flood management, the 2022 Central Valley Flood Protection Plan states clearly: Catastrophic flooding in the San Joaquin Basin is not a question of if, but when. Meanwhile, the reliability of water supplies is expected to worsen, and ecosystems face degradation.  Click here for the California Department of Water Resources Watershed Studies home page

San Joaquin Basin Flood‑MAR Watershed Studies Calaveras Watershed Study Area Report

California Department of Water Resources (DWR) | December 3rd, 2025

The San Joaquin Basin Flood‑MAR Watershed Studies (Watershed Studies) — comprising five watershed reports for Calaveras, Stanislaus, Tuolumne, Merced and Upper San Jo

The San Joaquin Basin Flood‑MAR Watershed Studies (Watershed Studies) — comprising five watershed reports for Calaveras, Stanislaus, Tuolumne, Merced and Upper San Joaquin watersheds and a Basinwide Summary — deliver data‑driven assessments of climate change vulnerabilities and adaptation that reveal risks and consequences and call for bold, coordinated solutions. In the San Joaquin Basin, the effects of climate change will exacerbate long-standing water management challenges. As these reports quantify, every water management sector — flood, water supply (surface and groundwater), and ecosystems — is vulnerable. Without bold action, the basin and its watersheds face mounting threats to communities, economies, and ecosystems. Although each watershed has unique characteristics, all confront a future climate that is hotter and characterized by more extreme weather. For flood management, the 2022 Central Valley Flood Protection Plan states clearly: Catastrophic flooding in the San Joaquin Basin is not a question of if, but when. Meanwhile, the reliability of water supplies is expected to worsen, and ecosystems face degradation. Click here to be taken to the California Department of Water Resources Watershed Studies home page

San Joaquin Basin Flood‑MAR Watershed Studies Merced Watershed Study Area Report

California Department of Water Resources (DWR) | December 3rd, 2025

The San Joaquin Basin Flood‑MAR Watershed Studies (Watershed Studies) — comprising five watershed reports for Calaveras, Stanislaus, Tuolumne, Merced and Upper San Jo

The San Joaquin Basin Flood‑MAR Watershed Studies (Watershed Studies) — comprising five watershed reports for Calaveras, Stanislaus, Tuolumne, Merced and Upper San Joaquin watersheds and a Basin-wide Summary — deliver data‑driven assessments of climate change vulnerabilities and adaptation that reveal risks and consequences and call for bold, coordinated solutions. In the San Joaquin Basin, the effects of climate change will exacerbate long-standing water management challenges. As these reports quantify, every water management sector — flood, water supply (surface and groundwater), and ecosystems — is vulnerable. Without bold action, the basin and its watersheds face mounting threats to communities, economies, and ecosystems. Although each watershed has unique characteristics, all confront a future climate that is hotter and characterized by more extreme weather. For flood management, the 2022 Central Valley Flood Protection Plan states clearly: Catastrophic flooding in the San Joaquin Basin is not a question of if, but when. Meanwhile, the reliability of water supplies is expected to worsen, and ecosystems face degradation. Click here for the California Department of Water Resources Watershed Studies homepage

San Joaquin Basin Flood‑MAR Watershed Studies Stanislaus Watershed Study Area Report

California Department of Water Resources (DWR) | December 3rd, 2025

The San Joaquin Basin Flood‑MAR Watershed Studies (Watershed Studies) — comprising five watershed reports for Calaveras, Stanislaus, Tuolumne, Merced and Upper San Jo

The San Joaquin Basin Flood‑MAR Watershed Studies (Watershed Studies) — comprising five watershed reports for Calaveras, Stanislaus, Tuolumne, Merced and Upper San Joaquin watersheds and a Basin-wide Summary — deliver data‑driven assessments of climate change vulnerabilities and adaptation that reveal risks and consequences and call for bold, coordinated solutions. In the San Joaquin Basin, the effects of climate change will exacerbate long-standing water management challenges. As these reports quantify, every water management sector — flood, water supply (surface and groundwater), and ecosystems — is vulnerable. Without bold action, the basin and its watersheds face mounting threats to communities, economies, and ecosystems. Although each watershed has unique characteristics, all confront a future climate that is hotter and characterized by more extreme weather. For flood management, the 2022 Central Valley Flood Protection Plan states clearly: Catastrophic flooding in the San Joaquin Basin is not a question of if, but when. Meanwhile, the reliability of water supplies is expected to worsen, and ecosystems face degradation. Click here to be taken to the California Department of Water Resources Watershed Studies homepage

San Joaquin Basin Flood‑MAR Watershed Studies Tuolumne Watershed Study Area Report

California Department of Water Resources (DWR) | December 3rd, 2025

The San Joaquin Basin Flood‑MAR Watershed Studies (Watershed Studies) — comprising five watershed reports for Calaveras, Stanislaus, Tuolumne, Merced and Upper San Jo

The San Joaquin Basin Flood‑MAR Watershed Studies (Watershed Studies) — comprising five watershed reports for Calaveras, Stanislaus, Tuolumne, Merced and Upper San Joaquin watersheds and a Basin-wide Summary — deliver data‑driven assessments of climate change vulnerabilities and adaptation that reveal risks and consequences and call for bold, coordinated solutions. In the San Joaquin Basin, the effects of climate change will exacerbate long-standing water management challenges. As these reports quantify, every water management sector — flood, water supply (surface and groundwater), and ecosystems — is vulnerable. Without bold action, the basin and its watersheds face mounting threats to communities, economies, and ecosystems. Although each watershed has unique characteristics, all confront a future climate that is hotter and characterized by more extreme weather. For flood management, the 2022 Central Valley Flood Protection Plan states clearly: Catastrophic flooding in the San Joaquin Basin is not a question of if, but when. Meanwhile, the reliability of water supplies is expected to worsen, and ecosystems face degradation. Click here for the California Department of Water Resources Watershed Studies home page

San Joaquin Basin Flood‑MAR Watershed Studies Upper San Joaquin Watershed Study Area Report

California Department of Water Resources (DWR) | December 3rd, 2025

The San Joaquin Basin Flood‑MAR Watershed Studies (Watershed Studies) — comprising five watershed reports for Calaveras, Stanislaus, Tuolumne, Merced and Upper San Jo

The San Joaquin Basin Flood‑MAR Watershed Studies (Watershed Studies) — comprising five watershed reports for Calaveras, Stanislaus, Tuolumne, Merced and Upper San Joaquin watersheds and a Basinwide Summary — deliver data‑driven assessments of climate change vulnerabilities and adaptation that reveal risks and consequences and call for bold, coordinated solutions. In the San Joaquin Basin, the effects of climate change will exacerbate long-standing water management challenges. As these reports quantify, every water management sector — flood, water supply (surface and groundwater), and ecosystems — is vulnerable. Without bold action, the basin and its watersheds face mounting threats to communities, economies, and ecosystems. Although each watershed has unique characteristics, all confront a future climate that is hotter and characterized by more extreme weather. For flood management, the 2022 Central Valley Flood Protection Plan states clearly: Catastrophic flooding in the San Joaquin Basin is not a question of if, but when. Meanwhile, the reliability of water supplies is expected to worsen, and ecosystems face degradation. Click here to be taken to California Department of Water Resources Watershed Studies homepage

Santa Ana Watershed Basin Study

U.S. Bureau of Reclamation (USBR) | September 1st, 2013

The U.S. Department of the Interior’s WaterSMART (Sustain and Manage America’s Resources for Tomorrow) program allows all bureaus of the Department to collaboratively

The U.S. Department of the Interior’s WaterSMART (Sustain and Manage America’s Resources for Tomorrow) program allows all bureaus of the Department to collaboratively work with States, Tribes, local governments, and non-governmental organizations to pursue a sustainable water supply for the Nation. This is done through a framework that provides federal leadership and assistance on the efficient use of water, and by integrating water and energy policies to support the sustainable use of all natural resources. Basin Studies, one of the tools of this program, are basin-wide efforts to evaluate and address the impacts of climate change, and define options for meeting future water demands in river basins in the western United States where imbalances in water supply and demand exist or are projected. The Bureau of Reclamation (Reclamation) and the Santa Ana Watershed Project Authority (SAWPA) partnered in the WaterSMART Santa Ana Watershed Basin Study (Study). The work done under the Study was used to help SAWPA update its One Water One Watershed (OWOW) Plan. OWOW is an Integrated Regional Water Management Plan (IRWMP) for the Santa Ana River Watershed (SARW) that serves as the blueprint for SAWPA, its member agencies and key stakeholders to effectively manage water resources over the next 30 years. The Santa Ana Watershed Basin Study illustrates how effective collaboration can improve water management. This Study takes a crest-to-coast and corner-to-corner approach throughout a 2,400-square-mile watershed, which encompasses everything from beach to mountain communities, to address the area’s unique water resource challenges. The SARW is home to more than 6 million people, and tens of millions more people visit the area each year. The region also has a large manufacturing, industrial, and agricultural base. More than 350 water, wastewater, and groundwater management, flood control, environmental and other non-governmental organizations, are working together as partners with SAWPA on the OWOW Plan. Through the Basin Study Program, Reclamation is partnering with SAWPA and its stakeholders to update key components of the Plan, now known as OWOW 2.0.  

Santa Ana Winds of Southern California: Their climatology, extremes, and behavior spanning six and a half decades

American Geophysical Union (AGU) | March 24th, 2016

Santa Ana Winds (SAWs) are an integral feature of the regional climate of Southern California/Northern Baja California region, but their climate-scale behavior is poorly

Santa Ana Winds (SAWs) are an integral feature of the regional climate of Southern California/Northern Baja California region, but their climate-scale behavior is poorly understood. In the present work,we identify SAWs in mesoscale dynamical downscaling of a global reanalysis from 1948 to 2012. Model windsare validated with anemometer observations. SAWs exhibit an organized pattern with strongest easterlywinds on westward facing downwind slopes and muted magnitudes at sea and over desert lowlands. Weconstruct hourly local and regional SAW indices and analyze elements of their behavior on daily, annual, andmultidecadal timescales. SAWs occurrences peak in winter, but some of the strongest winds have occurred infall. Finally, we observe that SAW intensity is influenced by prominent large-scale low-frequency modes ofclimate variability rooted in the tropical and north Pacific ocean-atmosphere system.

Satellite observations indicate that chia uses less water than other crops in warm climates

Nature Portfolio (Springer Nature) | September 30th, 2024

Scattered tree death contributes to substantial forest loss in California

Nature Portfolio (Springer Nature) | January 20th, 2024

In recent years, large-scale tree mortality events linked to global change have occurred around the world. Current forest monitoring methods are crucial for identifying m

In recent years, large-scale tree mortality events linked to global change have occurred around the world. Current forest monitoring methods are crucial for identifying mortality hotspots, but systematic assessments of isolated or scattered dead trees over large areas are needed to reduce uncertainty on the actual extent of tree mortality. Here, we mapped individual dead trees in California using sub-meter resolution aerial photographs from 2020 and deep learning-based dead tree detection. We identified 91.4 million dead trees over 27.8 million hectares of vegetated areas (16.7-24.7% underestimation bias when compared to field data). Among these, a total of 19.5 million dead trees appeared isolated, and 60% of all dead trees occurred in small groups ( ≤ 3 dead trees within a 30 × 30 m grid), which is largely undetected by other state-level monitoring methods. The widespread mortality of individual trees impacts the carbon budget and sequestration capacity of California forests and can be considered a threat to forest health and a fuel source for future wildfires.