Drinking Water Quality Report 2018

Los Angeles Department of Water & Power (LADWP) | September 2nd, 2019

Drinking Water Treatment and Distribution (Resource Management Strategy)

California Department of Water Resources (DWR) | July 29th, 2016

Providing a reliable supply of safe drinking water is the primary goal of public water systems in California. To achieve this goal, public water systems must develop and

Providing a reliable supply of safe drinking water is the primary goal of public water systems in California. To achieve this goal, public water systems must develop and maintain adequate water treatment and distribution facilities. In addition, the reliability, quality, and safety of the raw water supply are critical to achieving this goal. In general, public water systems depend greatly on the work of other entities to help protect and maintain the quality of the raw water supply. Many agencies and organizations have a role in protecting water supplies in California. For example, the basin plans developed by the regional water quality control boards recognize the importance of this goal and emphasize protecting water supplies — both groundwater and surface water. A public water system is defined as a system for the provision of water for human consumption, through pipes or other constructed conveyances, which has 15 or more service connections or regularly serves at least 25 individuals daily at least 60 days of the year (Health and Safety Code Section 116275[h]). Public water systems are divided into three principle classifications: community water systems (CWS), non-transient non-community (NTNC) water systems, and transient non-community (TNC) water systems. As the name indicates, CWS serve cities, towns, and other residential facilities occupied by year-round users. Examples include everything from apartment complexes served by their own wells to systems serving California’s largest cities. NTNC systems are public water systems that are not CWS and provide water to the same non-residential users daily for at least 180 days of the year. Examples include schools, places of employment, and institutions. TNC systems are places that provide water for a population that mostly comes and goes. Examples include campgrounds, parks, ski resorts, rest stops, gas stations, and motels. CWS serve approximately million of the estimated 37.7 million people throughout the state, or 97 percent of the state’s population. The remaining estimated 1.1 million people in the state (3 percent of the population) receive their drinking water from private wells serving their individual residences or from other sources. Virtually every Californian and visitor to the state will use drinking water from a regulated public water system through their work, while on vacation, or while traveling through the state.

Drip Irrigation

Scientific American | November 1st, 1977

Some 40 years ago Symcha Blass, an Israeli engineer, observed that a large tree near a leaking faucet exhibited a more vigorous growth than the other trees in the are

Some 40 years ago Symcha Blass, an Israeli engineer, observed that a large tree near a leaking faucet exhibited a more vigorous growth than the other trees in the area, which were not reached by the water from the faucet. Blass knew that conventional methods of irrigation waste much of the water that is applied to the crop, and so the example of the leaking faucet led him to the concept of an irrigation system that would apply water in small amounts. literally drop by drop. Eventually he devised and patented a low-pressure system for delivering small amounts of water to the roots of plants at frequent intervals. The technique, as developed by Blass and subsequently refined by him and various manufacturers, consists in laying a plastic tube of small diameter on the surface of the field alongside the plants and delivering water to the plants slowly but frequently from holes or special emitters located at appropriate points along the tube. The concept, which is now called drip irrigation or trickle irrigation, has gained wide acceptance, proving to be particularly valuable in areas that are arid and have high labor costs. An unforeseen benefit is that the system works well with water that is highly saline, as water in arid regions often is.

Driving forces of land surface temperature anomalous changes in North America in 2002–2018

Nature Portfolio (Springer Nature) | April 24th, 2020

The land surface temperature (LST) changes in North America are very abnormal recently, but few studies have systematically researched these anomalies from seve

The land surface temperature (LST) changes in North America are very abnormal recently, but few studies have systematically researched these anomalies from several aspects, especially the influencing forces. After reconstructing higher quality MODIS monthly LST data (0.05° * 0.05°) in 2002–2018, we analyzed the LST changes especially anomalous changes and their driving forces in North America. Here we show that North America warmed at the rate of 0.02 °C/y. The LST changes in three regions, including frigid region in the northwestern (0.12 °C/y), the west coast from 20°N–40°N (0.07 °C/y), and the tropics south of 20°N (0.04 °C/y), were extremely abnormal. The El Nino and La Nina were the main drivers for the periodical highest and lowest LST, respectively. The North Atlantic Oscillation was closed related to the opposite change of LSt in the northeastern north America and the southeastern United States, and the warming trend of the Florida peninsula in winter was closely related to enhancement of the North Atlantic Oscillation index. The Pacific Decadal Oscillation index showed a positive correlation with the LST in most Alaska. Vegetation and atmospheric water vapor also had a profound influence on the LST changes, but it had obvious difference in latitude.

Drought and Equity in California

Pacific Institute | January 9th, 2017

Drought and Equity in California is the first statewide analysis of the impacts of the drought on California’s most vulnerable communities. This report provides informa

Drought and Equity in California is the first statewide analysis of the impacts of the drought on California’s most vulnerable communities. This report provides information community groups can use to advocate for their own interests, as well as to inform policymakers and other decision-makers interested in crafting more effective drought response strategies, particularly to address the needs of the state’s most vulnerable communities. The report finds that during the state’s ongoing drought, water shortages and price hikes affected access to safe, affordable water for Californians, with substantial impacts on low-income families and communities burdened with environmental pollution. The report also examines the effects of a rapidly declining salmon population on commercial and tribal fishermen and finds that the decline and variability of salmon populations during droughts has impacted those dependent on the fish for income, food, and cultural traditions.

Drought and Equity in the San Francisco Bay Area

Pacific Institute | June 29th, 2016

California’s ongoing drought has wide-reaching impacts, from how we grow crops to the price of electricity. Often overlooked is its impact on disadvantaged communities.

California’s ongoing drought has wide-reaching impacts, from how we grow crops to the price of electricity. Often overlooked is its impact on disadvantaged communities. The Pacific Institute and The Environmental Justice Coalition for Water (EJCW) conducted community-based participatory research with eight Bay Area community-based groups to explore and document the drought’s impacts on low-income people in the San Francisco Bay Area. Through a series of collaborative meetings, surveys, and in-depth analyses of data, the group produced a groundbreaking report that sheds light on specific drought-related hardships faced by low-income residents and offers recommendations for mitigating those impacts. “This report is the first examination of the drought’s impacts on low-income communities in the Bay Area,” says Colin Bailey, Executive Director of EJCW. “Contrary to the conventional wisdom, the report shows the same hardships that befall California’s more rural communities are present in urban areas as well. The report calls on decision makers to account for and address these inequities in our drought responses.” The project team examined available data on drought impacts for the Bay Area, such as the number of households without water. The group identified affordability and water infrastructure conditions as key concerns for low-income communities, along with inequitable water use, whereby wealthier households typically use more water than lower income households. These are persistent concerns in many communities but have been exacerbated by the drought.

Drought and Groundwater Sustainability in California’s Farming Regions

Public Policy Institute of California (PPIC) | June 25th, 2024

Drought and ozone air quality in California: Identifying susceptible regions in the preparedness of future drought

Environmental Research (Elsevier) | October 19th, 2022

California experienced extreme and prolonged drought conditions during the early 2010s. To date, little is known regarding the influence of drought on air quality. Our st

California experienced extreme and prolonged drought conditions during the early 2010s. To date, little is known regarding the influence of drought on air quality. Our study quantified site-specific associations between drought (defined by the Standardized Precipitation-Evapotranspiration Index; SPEI) and daily maximum 8-h ozone (O3) concentrations for California, USA, and then pooled these associations for the years 2009–2015. Overall, ambient O3 concentration was higher during droughts by 1.18 ppb (95% confidence interval (CI) = 1.00–1.36). The sensitivity of O3 to drought was greater during the warm season than during the cool season (1.73 ppb versus 0.79 ppb higher O3 during droughts) with substantial regional variation. In a pooled analysis with meteorological parameters as potential effect modifiers, the spatial heterogeneity of drought-O3 associations was explained strongly by average relative humidity for each season (71.9% (warm season) and 73.4% (cool season) of the drought-O3 associations explained), followed by the drought-related changes in relative humidity (47.6% (warm season)) and temperature (53.6% (cool season)). The pooled regression further identified regions susceptible for drought-related O3 increases as those with relatively low average relative humidity (10–25th percentiles or 44.3–47.3%) and larger drought-related decrease in relative humidity and increase in temperature. As the drought events are projected to occur with increased frequency and intensity in the era of climate change, the excess health burdens from O3 exposures attributed to the projected drought events need to be taken into account when allocating air quality and health resources. The impacts of O3 on health during droughts would confound the health burdens from the drought itself.

Drought and the California Delta—A Matter of Extremes

University of California, Davis (UC Davis) | July 14th, 2014

California is in an extreme drought as a result of low precipitation in water year 2012, record low precipitation in 2013, and the remarkably dry first few months of 2014

California is in an extreme drought as a result of low precipitation in water year 2012, record low precipitation in 2013, and the remarkably dry first few months of 2014. We typically receive our largest precipitation totals in Decembers and Januaries (which provide about 36% of the precipitation in the Delta’s catchment), and when those months are as dry as they were this year, subsequent months have to be unseasonably wet to avoid drought. Most of the current winter, especially December 2013–January 2014, was dry because a persistent ridge of high (atmospheric) pressures set up offshore, diverting storms away from California and into Alaska. That same diversion gave the Delta’s catchment its warmest winter in 120 years, as well as bringing all that cold weather to the eastern US. While the February 2014 storms provided minor relief and momentarily slowed the spiral into deeper drought, the drought continues apace. Nonetheless, as harsh as it is, the current drought is not unprecedented in the Delta’s history, and even less so in its prehistory. In this essay, we consider the ways that droughts in California arise from a few missing storms and from long-term variations and changes in climate, in order to identify drought-science needs for Delta management. 

Drought and Water Year 2016: Hot and Dry Conditions Continue

California Department of Water Resources (DWR) | September 15th, 2016

Drought is a recurring feature of California’s climate. Paleoclimate information, such as streamflow or precipitation reconstructions developed from tree-ring d

Drought is a recurring feature of California’s climate. Paleoclimate information, such as streamflow or precipitation reconstructions developed from tree-ring data, can provide a perspective on long-term climate variability. Reconstructed hydrologic records show that California has experienced droughts of much longer duration than those in our century- plus recorded historical period. There is, however, one drought within the historical period on a par with driest events in the paleo record, if the comparison is made using driest 10-year streamflow periods. The prolonged off-and-on dry conditions of the 1920s-30s were severe in terms of their hydrology, but they occurred at a time when the state’s population was in the ballpark of 6 million and irrigated acreage was less than half of present levels.