California against the sea

Los Angeles Times | July 7th, 2019

THE CALIFORNIA COAST GREW AND PROSPERED during a remarkable moment in history when the sea was at its tamest. But the mighty Pacific, unbeknownst to all, was nearing i

THE CALIFORNIA COAST GREW AND PROSPERED during a remarkable moment in history when the sea was at its tamest. But the mighty Pacific, unbeknownst to all, was nearing its final years of a calm but unusual cycle that had lulled dreaming settlers into a false sense of endless summer. Elsewhere, Miami has been drowning, Louisiana shrinking, North Carolina’s beaches disappearing like a time lapse with no ending. While other regions grappled with destructive waves and rising seas, the West Coast for decades was spared by a rare confluence of favorable winds and cooler water. This “sea level rise suppression,” as scientists call it, went largely undetected. Blinded from the consequences of a warming planet, Californians kept building right to the water’s edge. But lines in the sand are meant to shift. In the last 100 years, the sea rose less than 9 inches in California. By the end of this century, the surge could be greater than 9 feet.

California Climate Adaptation Strategy (2009)

California Natural Resources Agency (CNRA) | December 1st, 2009

Climate change is already affecting California. Sea levels have risen by as much as seven inches along the California coast over the last century, increasing erosion and

Climate change is already affecting California. Sea levels have risen by as much as seven inches along the California coast over the last century, increasing erosion and pressure on the state’s infrastructure, water supplies, and natural resources. The state has also seen increased average temperatures, more extreme hot days, fewer cold nights, a lengthening of the growing season, shifts in the water cycle with less winter precipitation falling as snow, and both snowmelt and rainwater running off sooner in the year. These climate driven changes affect resources critical to the health and prosperity of California. For example, forest wildland fires are becoming more frequent and intense due to dry seasons that start earlier and end later. The state’s water supply, already stressed under current demands and expected population growth, will shrink under even the most conservative climate change scenario. Almost half a million Californians, many without the means to adjust to expected impacts, will be at risk from sea level rise along bay and coastal areas. California’s infrastructure is already stressed and will face additional burdens from climate risks. And as the Central Valley becomes more urbanized, more people will be at risk from intense heat waves.

California Climate Science and Data for Water Resources Management

California Department of Water Resources (DWR) | July 6th, 2015

Climate change creates critical challenges for California water resources management. The vulnerability of the water sector to climate change stems from a modified hydrol

Climate change creates critical challenges for California water resources management. The vulnerability of the water sector to climate change stems from a modified hydrology that affects the frequency, magnitude, and duration of extreme events, which, in turn, affect water quantity, quality, and infrastructure. Warmer temperatures drive the snow line higher and reduce snowpack, resulting in less water storage. Intense rainfall events will continue to affect the state, possibly leading to more frequent and/or more extensive flooding. The acceleration of sea level rise will produce higher storm surges during coastal storms. Droughts are likely to become more frequent and persistent during this century. Because California contains multiple climate zones, each region of the state will experience a combination of impacts from climate change unique to that area. While significant uncertainties still remain for local precipitation and temperature changes, projections at the regional and statewide levels are already available. Water supply managers in California have multiple tools and institutional capabilities to limit vulnerability to changing conditions, which can also serve as response mechanisms to a wide range of climate changes. This brochure summarizes the observations, projections, and challenges that climate change poses for water resources management in California, and highlights climate change content developed for the California Water Plan Update 2013.

California Department of Water Plan 2023: Navigating Climate Challenges with Equity and Resilience

California Department of Water Resources (DWR) | September 20th, 2023

The California Water Plan (Water Plan), updated every five years, is the State’s strategic plan for sustainably and equitably managing, developing, and stewarding water

The California Water Plan (Water Plan), updated every five years, is the State’s strategic plan for sustainably and equitably managing, developing, and stewarding water resources. Required by Water Code Section 10005, the plan presents the status and trends of California’s water-dependent natural resources; water supplies; and agricultural, urban, and environmental water demands for a range of plausible future scenarios.

California Department of Water Resources Baseline Greenhouse Gas Emissions Inventory 1990

California Department of Water Resources (DWR) | October 12th, 2012

The California Department of Water Resources (DWR) provides water management and planning services for the State of California. DWR is located within the California Natur

The California Department of Water Resources (DWR) provides water management and planning services for the State of California. DWR is located within the California Natural Resources Agency. DWR’s operations include ownership, operation, and maintenance of the State Water Project (SWP), operations and maintenance of flood protection facilities throughout the Central Valley, administration of several grant programs which dispense state funds to local and regional water authorities, and regulatory authority over dam safety throughout California. This baseline greenhouse gas (GHG) emissions inventory has been developed to supplement information provided in DWR’s Climate Action Plan Phase I: Greenhouse Gas Emissions Reduction Plan (GGERP) (http://www.water.ca.gov/climatechange/CAP.cfm). The GGERP documents DWR’s historical, current, and projected future GHG emissions, establishes and articulates GHG emissions reduction goals for 2020 and 2050, and describes the GHG emissions reduction measures that DWR will implement to achieve those goals. In the GGERP, GHG emissions are broken up into four categories: Operation, Construction, Maintenance, and Business Activities. Emissions are broken up in this way because they relate to key distinctions in the way activities are managed within DWR and the ways in which GHG emissions reduction measures can be implemented within DWR’s existing organizational structure. This inventory is organized to comply with the GHG Protocol? Corporate Accounting and Reporting Standard developed by the World Resources Institute and World Business Council for Sustainable Development. Therefore, this inventory accounts for GHG emissions from DWR activities under the categories of Scope 1, 2, and 3 emissions. The information in this inventory is consistent with the information provided in the GGERP, uses the same base data, and only differs in the ways in which the data are categorized and summed.

California forest die-off linked to multi-year deep soil drying in 2012–2015 drought

Nature Portfolio (Springer Nature) | July 1st, 2019

Widespread episodes of recent forest die-off have been tied to the occurrence of anomalously warm droughts, although the underlying mechanisms remain inadequately

Widespread episodes of recent forest die-off have been tied to the occurrence of anomalously warm droughts, although the underlying mechanisms remain inadequately understood. California’s 2012–2015 drought, with exceptionally low precipitation and warmth, and widespread conifer death, provides an opportunity to explore the chain of events leading to forest die-off. Here, we present the spatial and temporal patterns of die-off and moisture deficit during California’s drought, based on field and remote sensing observations. We found that die-off was closely tied to multi-year deep-rooting-zone drying, and that this relationship provides a framework with which to diagnose and predict mortality. Marked tree death in an intensively studied Sierra Nevada forest followed a four-year moisture overdraft, with cumulative 2012–2015 evapotranspiration exceeding precipitation by ~1,500 mm, and subsurface moisture exhaustion to 5–15-m depth. Observations across the entire Sierra Nevada further linked tree death to deep drying, with die-off and moisture overdraft covarying across latitude and elevation. Unusually dense vegetation and warm temperatures accelerated southern Sierran evapotranspiration in 2012–2015, intensifying overdraft and compounding die-off by an estimated 55%. Climate change is expected to further amplify evapotranspiration and moisture overdraft during drought, potentially increasing Sierran tree death during drought by ~15–20% °C−1.

California Water Action Plan Implementation Report: 2014–2018 Summary of Accomplishments

California Natural Resources Agency (CNRA) | June 13th, 2019

California Water Plan 2013: Sacramento River Hydrologic Region Report

California Department of Water Resources (DWR) | October 30th, 2014

The Sacramento River Hydrologic Region (see Figure SR-1 includes the entire California drainage area of the Sacramento River (the state’s largest river) and its tributa

The Sacramento River Hydrologic Region (see Figure SR-1 includes the entire California drainage area of the Sacramento River (the state’s largest river) and its tributaries. The region extends from Chipps Island in Solano County north to Goose Lake in Modoc County. It is bounded by the Sierra Nevada on the east, the Coast Ranges on the west, the Cascade and Trinity mountains on the north, and the Sacramento-San Joaquin River Delta (Delta) on the south.  The Sacramento River Basin actually begins in Oregon, north of Goose Lake, a near-sink that intercepts the Pit River drainage at the California-Oregon border. Some key issues for this region are summarized here and discussed further later in this report. Agriculture. Between 2005 and 2010, the region supported about 1.95 million acres of irrigated agriculture on average. Approximately 1.58 million acres is irrigated on the valley floor. The surrounding mountain valleys add about 370,000 irrigated acres to the region’s total — primarily as pasture and alfalfa. The gross value of agricultural production in the Sacramento Valley for 2011 was about $4.1 billion (California Department of Food and Agriculture 2013). Rice and walnuts are the highest grossing crops in the region followed by almonds and tomatoes. The direct, indirect, and induced effects of the agricultural industry to the regional economy are discussed in this report. Groundwater. With a 2005-2010 average annual extraction volume of 2.7 million acre-feet (maf), groundwater pumping in the Sacramento River Hydrologic Region accounts for 17 percent of all the groundwater extraction in California — the third highest among the 10 hydrologic regions in California, behind Tulare Lake Hydrologic Region with 38 percent and San Joaquin River Hydrologic Region with 19 percent of the total. Overall, groundwater contributes to about 31 percent of the total water supply. Most groundwater extraction in the region occurs for agricultural water use (2.4 maf), meeting about one-third of agricultural water demands. Groundwater extraction for urban water use is significantly less (465 thousand acre-feet [taf]), which meets about half of the urban water needs. Groundwater levels for much of the region have declined from 2005 to 2010. Groundwater level declines ranging from 20 to 30 feet are seen in the northwestern portion of the Sacramento Valley Groundwater Basin. Declines ranging from to 10 to 20 feet are seen in the northern, the mid- to south-western, and the southeastern portions of the valley. For the rest of the Sacramento Valley Groundwater Basin and the Redding Area Groundwater Basin, groundwater level declines have ranged from zero to 10 feet. Flood. Exposure to a 500-year flood event in the region threatens approximately one in three residents, almost $65 billion in assets (crops, buildings, and public infrastructure), 1.2 million acres of agricultural land, and over 340 sensitive species. Almost 95 percent of Sutter County residents, more than 55 percent of Yuba County and Yolo County residents, and more than 50 percent of agricultural land region-wide are exposed to the 500-year flood event. Climate Change. Several different climate regions overlie portions of the Sacramento River Hydrologic Region. Air temperature data collected for the past century has been summarized by the Western Regional Climate Center (WRCC) for the different regions which are outlined below. Within the WRCC North Central climate region, mean temperatures have increased by about 0.8 to 1.7 °F (0.4 to 0.9 °C) in the past century, with minimum and maximum temperatures increasing by about 1.2 to 2.1 °F (0.7 to 1.2 °C) and 0.1 to 1.5 °F (0.1 to 0.8 °C), respectively. Within the WRCC North East climate region, mean temperatures have increased by about 0.8 to 2.0 °F (0.5 to 1.1 °C) in the past century, with minimum and maximum temperatures increasing by about 0.9 to 2.2 °F (0.5 to 1.2 °C) and by 0.5 to 2.1 °F (0.3 to 1.2 °C), respectively. Within the WRCC Sierra climate region, mean temperatures have increased by about 0.8 to 2.0 °F (0.5 to 1.1 °C) in the past century, with minimum and maximum temperatures increasing and decreasing by about 1.7 to 2.8 °F (0.9 to 1.5 °C) and by -0.2 to 1.3 °F (-0.1 to 0.7 °C), respectively. Within the WRCC Sacramento-Delta climate region, mean temperatures have increased by about 1.5 to 2.4 °F (0.9 to 1.3 °C) in the past century, with minimum and maximum temperatures increasing by about 2.1 to 3.1 °F (1.2 to 1.7 °C) and by 0.8 to 2.0 °F (0.4 to 1.1 °C), respectively (Western Regional Climate Center 2013). The region also is currently experiencing impacts from climate change through changes in statewide precipitation and surface runoff volumes, which in turn affect availability of local and imported water supplies. During the last century, the average early snowpack in the Sierra Nevada decreased by about 10 percent, which equates to a loss of 1.5 maf of snowpack storage (California Department of Water Resources 2008). Projections and impacts based on modeling of climate change are included in this report.

California Water Plan Update 2023 (Final Version)

California Department of Water Resources (DWR) | April 3rd, 2024

Updated every five years, the Water Plan is the State’s strategic plan for sustainably and equitably managing, developing, and stewarding water resources. Required by W

Updated every five years, the Water Plan is the State’s strategic plan for sustainably and equitably managing, developing, and stewarding water resources. Required by Water Code Section 10005, the plan presents the status and trends of California’s water-dependent natural resources; water supplies; and agricultural, urban, and environmental water demands for a range of plausible future scenarios.

California Water Resilience Portfolio

State of California | July 28th, 2020