Central Coast

Final Technical Report #1: Condition Assessment of Coastal Streams in Southern and Central California

California Department of Fish and Wildlife (CDFW) | July 1st, 2004

Historical assessments of stream condition have usually focused on describing the chemical quality of streams. As we have made progress in controlling chemical problems�

Historical assessments of stream condition have usually focused on describing the chemical quality of streams. As we have made progress in controlling chemical problems it has become obvious that the ultimate concern is actually the health of the plants and animals that inhabit these streams (EPA 2000). Streams in good ecological condition provide habitat for diverse aquatic communities, and provide clean drinking water and recreational opportunities for people. Biological organisms in a stream integrate the many chemical and physical stressors that act on the stream ecosystem, thus stream condition can be determined by assessing appropriate biological indicators, or combinations of these indicators, called indices. California’s Aquatic Bioassessment Lab recently developed a benthic index of biotic integrity (B-IBI) for the central and southern coasts of California (Ode et. al. in review). The index is based on benthic macroinvertebrate (BMI) samples collected from 275 sites in this region by the US Forest Service, US EPA and regional Water Quality Control Boards. The index defines the composition of BMI assemblages when human disturbance is absent or minimal (reference conditions), and because it is based on metrics that are responsive to key stressor gradients, it allows detection of potential ecological impairment when BMI samples from test sites are compared to reference conditions. Thus, the B-IBI provides a yardstick for measuring ecological conditions, and allows us to categorize site conditions as either “Good”, “Fair” or “Poor” based on BMI assemblages.

Final Urban Water Management Plan Goleta Water District

Goleta Water District (GWD) | December 20th, 2005

Fire (plus) flood (equals) beach: coastal response to an exceptional river sediment discharge event

Nature Portfolio (Springer Nature) | March 9th, 2022

Wildfire and post-fire rainfall have resounding effects on hillslope processes and sediment yields of mountainous landscapes. Yet, it remains unclear how fire–flood se

Wildfire and post-fire rainfall have resounding effects on hillslope processes and sediment yields of mountainous landscapes. Yet, it remains unclear how fire–flood sequences influence downstream coastal littoral systems. It is timely to examine terrestrial–coastal connections because climate change is increasing the frequency, size, and intensity of wildfires, altering precipitation rates, and accelerating sea-level rise; and these factors can be understood as contrasting accretionary and erosive agents for coastal systems. Here we provide new satellite-derived shoreline measurements of Big Sur, California and show how river sediment discharge significantly influenced shoreline positions during the past several decades. A 2016 wildfire followed by record precipitation increased sediment discharge in the Big Sur River and resulted in almost half of the total river sediment load of the past 50 years (~ 2.2 of ~ 4.8 Mt). Roughly 30% of this river sediment was inferred to be littoral-grade sand and was incorporated into the littoral cell, causing the widest beaches in the 37-year satellite record and spreading downcoast over timescales of years. Hence, the impact of fire–flood events on coastal sediment budgets may be substantial, and these impacts may increase with time considering projected intensification of wildfires and extreme rain events under global warming. Wildfire is an important factor in hillslope erosion and sediment yields of mountainous and forested

Fire influence on land–water interactions in aridland catchments

Oxford University Press (OUP) | January 9th, 2025

Wildfires have increased in size, frequency, and intensity in arid regions of the western United States because of human activity, changing land use, and rising temperatu

Wildfires have increased in size, frequency, and intensity in arid regions of the western United States because of human activity, changing land use, and rising temperature. Fire can degrade water quality, reshape aquatic habitat, and increase the risk of high discharge and erosion. Drawing from patterns in montane dry forest, chaparral, and desert ecosystems, we developed a conceptual framework describing how interactions and feedbacks among material accumulation, combustion of fuels, and hydrologic transport influence the effects of fire on streams. Accumulation and flammability of fuels shift in opposition along gradients of aridity, influencing the materials available for transport. Hydrologic transport of combustion products and materials accumulated after fire can propagate the effects of fire to unburned stream–riparian corridors, and episodic precipitation characteristic of arid lands can cause lags, spatial heterogeneity, and feedbacks in response. Resolving uncertainty in fire effects on arid catchments will require monitoring across hydroclimatic gradients and episodic precipitation.

Flood Plain Information, Montecito Streams, Vicinity of Montecito, Santa Barbara, California

U.S. Army Corps of Engineers (USACE) | June 28th, 1974

Due to size, this file has been divided. Part 1, Part 2, Part 3

Due to size, this file has been divided. Part 1, Part 2, Part 3

Flood Size Increases Nonlinearly Across the Western United States in Response to Lower Snow-Precipitation Ratios

American Geophysical Union (AGU) | December 20th, 2019

Many mountainous and high-latitude regions have experienced more precipitation as rain rather than snow due to warmer winter temperatures. Further decreases in the annual

Many mountainous and high-latitude regions have experienced more precipitation as rain rather than snow due to warmer winter temperatures. Further decreases in the annual snow fraction are projected under continued global warming, with potential impacts on flood risk. Here, we quantify the size of streamflow peaks in response to both seasonal and event-specific rain-fraction using stream gage observations from watersheds across the western United States. Across the study watersheds, the largest rainfall-driven streamflow peaks are >2.5 times the size of the largest snowmelt-driven peaks. Using a panel regression analysis of individual precipitation and snowmelt events, we show that the empirical streamflow response grows approximately exponentially as the liquid precipitation input increases, with rain-dominated runoff leading to proportionately larger streamflow increases than snowmelt or mixed rain-and-snow runoff. We find that the response to changes in rain percentage is largest in the wettest watersheds, where wet antecedent conditions are important for increasing runoff efficiency. Similarly, the effect of rain percentage is larger across watersheds in the Northwest and West regions compared to watersheds in the Northern Rockies and Southwest regions. Overall, as a higher percentage of precipitation falls as rain, increases in the size of rainfall-driven and “rain-on-snow”-driven floods have the potential to more than offset decreases in the size of snowmelt-driven floods.

Flood-MAR Research and Data Development Plan

California Department of Water Resources (DWR) | October 31st, 2019

The Research Advisory Committee (RAC) is pleased to make this plan available to the growing network of farmers, researchers, planners, and water and land managers who wan

The Research Advisory Committee (RAC) is pleased to make this plan available to the growing network of farmers, researchers, planners, and water and land managers who want to expand our collective knowledge about using floodwaters for managed aquifer recharge (Flood-MAR). This plan outlines the priority information needed by those making management decisions about the where, when, and how of capturing available flood water to replenish California’s depleted aquifers.

Floods in California

Public Policy Institute of California (PPIC) | February 29th, 2024

Forebay Aquifer Subbasin Groundwater Sustainability Plan

Salinas Valley Basin Groundwater Sustainability Agency | January 13th, 2022

The 2014 California Sustainable Groundwater Management Act (SGMA) requires that medium- and high-priority groundwater basins and subbasins develop Groundwater Sustainabil

The 2014 California Sustainable Groundwater Management Act (SGMA) requires that medium- and high-priority groundwater basins and subbasins develop Groundwater Sustainability Plans (GSPs) that outline how groundwater sustainably will first be maintained for 50 years. This GSP fulfills that requirement for the Salinas Valley—Forebay Aquifer Subbasin (Subbasin, or Forebay Subbasin), which is designated by the DWR as a medium priority groundwater subbasin. Plan approved by DWR 4/27/23.

Fourth National Climate Assessment Chapter 25: Southwest

U.S. Global Change Research Program | November 23rd, 2018

The Southwest region encompasses diverse ecosystems, cultures, and economies, reflecting a broad range of climateconditions, including the hottest and driest climate in t

The Southwest region encompasses diverse ecosystems, cultures, and economies, reflecting a broad range of climateconditions, including the hottest and driest climate in the United States. Arizona, California, Colorado, New Mexico, Nevada, and Utah occupy one-fifth of U.S. land area, extending across globally unique ecosystems from the Sonoran Desert to the Sierra Nevada to the Pacific Coast. The region is home to 60 million people, with 9 out of 10 living in urban areas and the total population growing 30% faster than the national average. The Nation depends on the region for more than half of its specialty crops such as fruits, nuts, and vegetables. The Southwest also drives the U.S. technology sector, with more than 80% of the country’s technology capitalization located in California. Click here for all chapters of the Fourth National Climate Assessment.