This article needs attention from an expert in climate change. The specific problem is: Insufficient documentation of the causes of the droughts.(January 2022) |
The historical and ongoing droughts in California result from various complex meteorological phenomena, some of which are not fully understood by scientists.
Drought is generally defined as "a deficiency of precipitation over an extended period of time (usually a season or more), resulting in a water shortage." [1]
A lack of rainfall (or snowfall) or precipitation in meager quantities, higher than average temperatures and dry air masses in the atmosphere commonly underlie drought conditions; these natural factors are further complicated by increases in populations and water demands. Since the California water supply is attained from numerous sources, fulfilled by varied and intricate weather patterns, there is no one cause of drought. California is not only the most populous state and largest agricultural producer in the United States, it is also the most biodiverse; [2] as such, drought in California can have a far reaching economic and environmental impacts.
There are five major technical categories of drought: (1) Meteorological, (2) Agricultural, (3) Hydrological, (4) Socioeconomic, and (5) Ecological. A meteorological drought may be short lived without causing disturbance; but when longer lasting may enter other categories according to its impacts. [3] [4] In addition to technical categories, Governor Gavin Newsom and his administration introduced in 2023 the concept of a political drought, where state public policy actions would need to continue even after short-term drought conditions may have ameliorated. [5]
Precipitation in California occurs mostly from November to May, with the vast majority of rain and snowfall across the state occurring during the winter months. This delicate balance means that a dry rainy season can have lasting consequences.
Drought is intrinsic to the natural climate of California. [6] Across the Californian region, paleoclimate records dating back more than 1,000 years show more significant dry periods compared to the latest century. Ancient data reveals two mega-droughts that endured for well over a century, one lasting 220 years and one for 140 years. The 20th century was fraught with numerous droughts, yet this era could be considered relatively "wet" compared against an expansive 3,500 year history. In recent times, droughts lasting five to 10 years have raised concern, but are not anomalous. Rather, decade long droughts are an ordinary feature of the state's innate climate. Based on scientific evidence, dry spells as severe as the mega-droughts detected from the distant past are likely to recur, even in absence of anthropogenic climate change. [7]
This section needs to be updated.(January 2022) |
According to the Intergovernmental Panel on Climate Change or IPCC, their Sixth Assessment Report (AR6) on the effects of climate change revealed a number of scientifically supported claims on what is to become the future of the earth. While variability in climate patterns are a natural occurrence, AR6 concluded that human influences have increased the chance of compound extreme weather events, specifically "increases in the frequency of concurrent heatwaves and droughts on the global scale" with high confidence. [8]
According to the NOAA Drought Task Force report of 2014, the drought is not part of a long-term change in precipitation and was a symptom of the natural variability, although the record-high temperature that accompanied the recent drought may have been amplified due to human-induced global warming. [9] This was confirmed by a 2015 scientific study which estimated that global warming "accounted for 8–27% of the observed drought anomaly in 2012–2014. Although natural variability dominates, anthropogenic warming has substantially increased the overall likelihood of extreme California droughts." [10] A study published in 2016 found that the net effect of climate change has made agricultural droughts less likely, with the authors also stating that "Our results indicate that the current severe impacts of drought on California’s agricultural sector, its forests, and other plant ecosystems have not been substantially caused by long-term climate change." [11]
Drought phases are integral to the climate of California. [7] Furthermore, global La Niña meteorological events are generally associated with drier and hotter conditions and further exacerbation of droughts in California and the Southwestern and to some extent Southeastern United States. Meteorological scientists have observed that La Niñas have become more frequent over time. [12]
Increasingly dramatic fluctuations in California weather have been observed in the 21st century. In 2015, California experienced its lowest snowpack in at least 500 years; the 2012–15 period was the driest in at least 1200 years. [13] [14] [15] [16] [17] [18] However, the winter of 2016–17 was the wettest ever recorded in Northern California, surpassing the previous record set in 1982–83. In February 2017, Shasta, Oroville and Folsom Lakes were simultaneously dumping water into the ocean for flood control. Lake Oroville flowed over the emergency spillway for the first time in 48 years, after the main spillway was damaged resulting in the temporary evacuation of 200,000 people. [19] The combined inflow to Shasta, Oroville and Folsom Lakes on February 9 was 764,445 acre-feet (0.942929 km3). Two days later, the combined flood control release was 370,260 acre-feet (0.45671 km3). [20] This water would have been worth $370M at Los Angeles County municipal rates.
Throughout recent recorded history, California has experienced periodic droughts, such as 1841, [21] 1864, 1895, 1924, 1928–1935, 1947–1950, 1959–1961, 1976–1977, 1986–1992, 2007–2009, [22] [21] and 2011–2017, and 2020–2022. [5]
Since 1841, the following dry years have had significantly below-average precipitation.
The drought was sufficiently severe that a settler's account of the time claimed that the Sonoma area was "entirely unsuitable for agriculture". [21]
This drought was preceded by the torrential floods of 1861–1862. [21]
This drought encouraged farmers to start using irrigation more regularly. Because of the fluctuation in California weather, the need for consistent water availability was crucial for farmers. [21]
This drought occurred during the historical Dust Bowl period that characterized much of the plains region of the United States in the 1920s and 1930s. [21] The Central Valley Project was started in the 1930s in response to drought. [23]
The 1950s drought contributed to the creation of the State Water Project. [23]
1977 had been the driest year in state history to date. [24] According to the Los Angeles Times, "Drought in the 1970s spurred efforts at urban conservation and the state's Drought Emergency Water Bank came out of drought in the 1980s.". [23]
Additionally as drought prediction was essentially random and in response to recent severe drought years, in 1977 the U.S. Department of the Interior, Office of Water Research and Technology contracted Entropy Limited for an exploratory study of the applicability of the entropy minimax method of statistical analysis of multivariate data to the problem of determining the conditional probability of drought one or two years into the future, with the area of special interest being California. Christensen et al. (1980) [25] demonstrated an information-theoretic model predicted the probability that precipitation will be below or above average with modest but statistically significant skill one, two and even three years into the future. It was this pioneering work that discovered the influence of El Nino El Nino-Southern Oscillation on US weather forecasting.
California endured one of its longest droughts ever, observed from late 1986 through late 1992. Drought worsened in 1988 as much of the United States also suffered from severe drought. In California, the six-year drought ended in late 1992 as a significant El Niño event in the Pacific Ocean (and the eruption of Mount Pinatubo in June 1991) most likely caused unusual persistent heavy rains. [26]
2007–2009 saw three years of drought conditions, the 12th worst drought period in the state's history, and the first drought for which a statewide proclamation of emergency was issued. The drought of 2007–2009 also saw greatly reduced water diversions from the state water project. The summer of 2007 saw some of the worst wildfires in Southern California history. [27]
2011-2017 was the longest drought in California beginning December 2011 and ending March 2017. [22]
The period between late 2011 and 2014 was the driest in California history since record-keeping began. [28] In May 2015, a state resident poll conducted by Field Poll found that two out of three respondents agreed that it should be mandated for water agencies to reduce water consumption by 25%. [29]
The 2015 prediction of El Niño to bring rains to California raised hopes of ending the drought. In the spring of 2015, the National Oceanic and Atmospheric Administration named the probability of the presence of El Niño conditions until the end of 2015 at 80%. Historically, El Niño conditions were present during sixteen winters between 1951 and 2015. Six of those had below-average rainfall, five had average rainfall, and five had above-average rainfall. However, as of May 2015, drought conditions had worsened and above average ocean temperatures had not resulted in large storms. [30]
The drought led to Governor Jerry Brown's instituting mandatory 25 percent water restrictions in June 2015. [31]
Many millions of California trees died from the drought – approximately 102 million, including 62 million in 2016 alone. [32] By the end of 2016, 30% of California had emerged from the drought, mainly in the northern half of the state, while 40% of the state remained in the extreme or exceptional drought levels. [33] Heavy rains in January 2017 were expected to have a significant benefit to the state's northern water reserves, despite widespread power outages and erosional damage in the wake of the deluge. [34] Among the casualties of the rain was 1,000 year-old Pioneer Cabin Tree in Calaveras Big Trees State Park, which toppled on January 8, 2017. [35]
The winter of 2016–17 turned out to be the wettest on record in Northern California, surpassing the previous record set in 1982–83. [36] Floodwaters caused severe damage to Oroville Dam in early February, prompting the temporary evacuation of nearly 200,000 people north of Sacramento. [37] In response to the heavy precipitation, which flooded multiple rivers and filled most of the state's major reservoirs, Governor Brown declared an official end to the drought on April 7. [38]
The runoff from rainfall used to support many aspects of California infrastructure, such as agriculture and municipal use, will be severely diminished during the drought. While groundwater diminishes at a much lower rate than runoff, the lack of runoff will lead to increased groundwater pumping to meet the needs of the water demand. If groundwater is being pumped at a rate higher than it can be replenished by precipitation then groundwater levels will begin to fall and the quality of water will also decrease. With that said the relationship between surface water and groundwater contribute to the hydrologic system, and groundwater helps maintain surface water flows during extended dry periods. With both sources diminishing, the quality and availability of water will decrease. People can become ill from lack of water.
Excessive ground water pumping and aquifer depletion will lead to land sinking and permanent loss of groundwater storage. Decreasing groundwater levels lead to exposing of underground water storage areas, this will cause lack of soil structure strength and possible sinking if the land above is heavy enough. This has already begun in certain parts of the state during the most recent drought. In coastal communities, excessive water pumping can lead to sea water intrusion, which means sea water will begin to flow into the underground water storage areas that were vacated by excess pumping. This can cause decreased water quality and lead to an expensive desalination effort to clean the water before distribution. Water flows through wildlife refuges and national parks can decrease or stop all together due to the decrease of surface and groundwater, the California Water Science Center is a part of a team trying to restore and maintain water flow in these at risk areas. With reduction of water flow and increased windy or dry weather, wildfire risks increase; lightning strikes or accidental human mistake can lead to huge wildfires due to the drier-than-normal climate. [39]
Adaptation is the process of adjusting to circumstances, which means not trying to stop the drought, but trying to preserve the water given the drought conditions. This is the most used option, because stopping a drought is difficult given that it is a meteorological process. Adapting to the problem using innovation and problem solving is often the cheaper and more useful way to go because trying to change the natural processes of the earth could have unforeseen consequences.
A precipitation shortage leaves less water in the state's water infrastructure systems, leading to debates on how to best make use of this limited resource.
Very few large-scale water projects have been built since 1979, despite the population doubling since that year. [42] [43]
Because much of California's water network relies on a system of pumps to move water from north to south, large volumes of water are often lost to the Pacific Ocean during winter storms when river flow exceeds the capacity of the pumps. This is further complicated by environmental rules which restrict pumping during certain months of the year, to protect migrating fish. In water year 2015, 9,400,000 acre-feet (11.6 km3) of water flowed through the Sacramento–San Joaquin River Delta, but only 1,900,000 acre-feet (2.3 km3) were recovered into water distribution systems. [44]
Most of California's major reservoirs serve important flood control functions. Due to the limited capacity of river channels and dam spillways, reservoirs cannot be quickly drained before major storms. This limits how much of a reservoir's capacity can be used for long-term storage. Reservoirs in California are designed to control either rain floods, snowmelt floods or both.
In the coastal and southern parts of the state, and much of the Sacramento River system, the primary threat is rain floods in the November–April wet season. Oceanic "atmospheric river" or Pineapple Express storms can generate massive precipitation in a short period (often up to 50 percent of the total annual rainfall in just a few storms). [45] This requires a certain safety margin to be maintained in reservoirs, which are often not allowed to capacity until late April or May. Shasta Lake, California's largest reservoir, is limited to approximately 71 percent of capacity in the winter in order to control rain flooding. Levees along Northern California rivers, such as the Sacramento and American rivers, are quite generously sized in order to pass large volumes of floodwater. [46]
In the San Joaquin River basin (San Joaquin Valley) and other areas of the state where snowpack is the primary source of river flow, river channels are sized mainly to control snowmelt floods, which do not produce the huge peaks typical of rain floods, but are longer in duration and have a much higher total volume. As a result, reservoirs in this region have very strict restrictions on the amount of water that can be released. An example of a reservoir operated for snow floods is Pine Flat Lake near Fresno, which is restricted to about 53 percent capacity well into spring in order to capture summer snowmelt. [47] However, Pine Flat and other San Joaquin reservoirs are frequently ineffectual in controlling rain floods, because they cannot release water fast enough between winter storms. [47] [48] [ page needed ]
Certain parts of the state, especially in the central Sierra Nevada, are prone to both rain and snow floods. Reservoirs such as Lake Oroville and Folsom Lake must respond to a wider range of runoff conditions. Lake Oroville is typically limited to 79–89 percent of capacity during the winter and Folsom Lake to 33–60 percent. These values are often adjusted up and down based on the amount of rain and snow forecast. [46] At Folsom Lake, due to the small size of the reservoir, it is difficult to balance the need for winter flood-control space with the need to store water for the summer. This often results in a failure to fill the lake due to a lower than expected spring snowmelt. Water managers and hydrology experts have criticized the outdated, overly conservative operation criteria at Folsom Dam, citing improved weather forecasting and snowpack measurement technology. [49]
Progress in forecasting methods has allowed more efficient or "smart" operation at certain California reservoirs, such as Lake Mendocino. If dry weather is forecast, water is allowed to be stored above the legal flood control limit, rather than being wasted downstream. This program is known as "Forecast Informed Reservoir Operations". [50] In addition, capital improvements such as the $900 million spillway project at Folsom Dam [51] will allow greater flexibility in water releases, making it safer to maintain a high reservoir level during the wet season.
Flood control limitations at selected California reservoirs [47] | ||||||||
---|---|---|---|---|---|---|---|---|
Reservoir | River | Capacity | Max. flood control reservation | Percent of total capacity reserved for flood control | Target flood water release | |||
Acre feet | km3 | Acre feet | km3 | ft3/s | m3/s | |||
Shasta Lake | Sacramento River | 4,552,000 | 5.615 | 1,300,000 | 1.6 | 28.5% | 79,000 | 2,200 |
Lake Oroville | Feather River | 3,540,000 | 4.37 | 750,000 | 0.93 | 21.1% | 150,000 | 4,200 |
New Bullards Bar Reservoir | Yuba River | 966,000 | 1.192 | 170,000 | 0.21 | 17.6% | 50,000 | 1,400 |
Folsom Lake | American River | 977,000 | 1.205 | 670,000 | 0.83 | 68.5% | 115,000 | 3,300 |
Camanche Lake | Mokelumne River | 417,000 | 0.514 | 200,000 | 0.25 | 48.0% | 5,000 | 140 |
New Hogan Lake | Calaveras River | 317,000 | 0.391 | 165,000 | 0.204 | 52.1% | 12,500 | 350 |
New Melones Lake | Stanislaus River | 2,420,000 | 2.99 | 450,000 | 0.56 | 18.6% | 8,000 | 230 |
Lake Don Pedro | Tuolumne River | 2,030,000 | 2.50 | 340,000 | 0.42 | 16.7% | 9,000 | 250 |
Lake McClure | Merced River | 1,025,000 | 1.264 | 350,000 | 0.43 | 34.2% | 6,000 | 170 |
Millerton Lake | San Joaquin River | 521,000 | 0.643 | 391,000 | 0.482 | 75.0% | 8,000 | 230 |
Pine Flat Lake | Kings River | 1,000,000 | 1.2 | 475,000 | 0.586 | 47.5% | 7,950 | 225 |
Lake Isabella [52] | Kern River | 568,000 | 0.701 | 398,000 | 0.491 | 70.1% | 4,600 | 130 |
California has one of the most variable climates of any U.S. state, and often experiences very wet years followed by extremely dry ones. [53] The state's reservoirs have insufficient capacity to balance the water supply between wet and dry years.
El Niño and La Niña have often been associated with wet and dry cycles in California, respectively (the 1982–83 El Niño event, one of the strongest in history, brought record precipitation to the state), but recent climate data show mixed evidence for such a relationship due in part to the growing impact of human-induced global warming. The very wet 2010–2011 season occurred during a strong La Niña phase, while the 2014–16 El Niño event, which surpassed 1982–83 in intensity, did not bring an appreciable increase of precipitation to the state.
The 2012–15 North American drought was caused by conditions of the Arctic oscillation and North Atlantic oscillation which removed storms from the U.S. in the winter of 2011–2012.
Meeting EPA water quality standards currently requires allowing billions of gallons per day to flow into the ocean. [58]
On March 20, 2023, Trinity Lake was losing 1 billion gallons per day to Flow Augmentation. [59] This happened during historic drought, while Trinity was at only 50% of historical average, and all other major California lakes were at least 91% of historical average. The Trinity River Restoration Program is responsible for regulating the flow. [60]
Water in California can be expensive. [61] This leads to awareness of water management challenges. [62]
In some instances, water tables underground have dropped from 100 to 400–600 feet deep, basically shutting off most private well owners from their own water sources. [63]
Water is managed by government consent, which assumes ownership and management of all free flowing rivers, lakes, and bodies of water in its jurisdictions. In many cases in the US, water has been used for commercial purposes, such as Nestle's 72 brands of bottled water. It is managed by governmental authorities selling its water rights. Some local and state governments have resorted to selling water rights for income even when it harms the local community and environment [64] (e.g. taking water away from California and bottling and shipping it to water-rich parts of the United States and the world for profit). This has led many to criticize treating water as a commodity. [65] [66]
Despite Nestle's claims of acting according to the law, however, in 2017 California authorities found that the company extracted 58 million gallons, far surpassing the 2.3 million gallons per year it had rights to claim. [67] Lately, locals have been fighting back against the "stealing" of precious resources by opposing and not allowing huge water draw down facilities to be set up. [68] For example, officials at California's State Water Resources Control Board have made moves to prevent Nestlé from draining millions of gallons of water from the San Bernardino National Forest. [64] [69] [70] Nestle's continued bottling in the forest after its permit to do so was expired by decades. [71] In doing so, Nestle depleted Strawberry Creek. [70]
Another bottled water company, Crystal Geyser, was found to be illegally transporting and dumping arsenic-laded wastewater from its bottling facilities. [72]
Orange County is working toward water independence by building the world's largest indirect potable water recycling project – the Groundwater Replenishment System. [73] Poseidon Water is also developing a seawater desalination plant in Huntington Beach [74] for Orange County and has already built and is operating a seawater desalination plant in Carlsbad [75] for San Diego County. Combined the two plants will provide 100 million gallons of drinking water per day, or enough water for about 800,000 people.[ citation needed ]
A drought is a period of drier-than-normal conditions. A drought can last for days, months or years. Drought often has large impacts on the ecosystems and agriculture of affected regions, and causes harm to the local economy. Annual dry seasons in the tropics significantly increase the chances of a drought developing, with subsequent increased wildfire risks. Heat waves can significantly worsen drought conditions by increasing evapotranspiration. This dries out forests and other vegetation, and increases the amount of fuel for wildfires.
The Central Valley is a broad, elongated, flat valley that dominates the interior of California. It is 40–60 mi (60–100 km) wide and runs approximately 450 mi (720 km) from north-northwest to south-southeast, inland from and parallel to the Pacific coast of the state. It covers approximately 18,000 sq mi (47,000 km2), about 11% of California's land area. The valley is bounded by the Coast Ranges to the west and the Sierra Nevada to the east.
The water cycle is a biogeochemical cycle that involves the continuous movement of water on, above and below the surface of the Earth. The mass of water on Earth remains fairly constant over time. However, the partitioning of the water into the major reservoirs of ice, fresh water, salt water and atmospheric water is variable and depends on climatic variables. The water moves from one reservoir to another, such as from river to ocean, or from the ocean to the atmosphere. The processes that drive these movements are evaporation, transpiration, condensation, precipitation, sublimation, infiltration, surface runoff, and subsurface flow. In doing so, the water goes through different forms: liquid, solid (ice) and vapor. The ocean plays a key role in the water cycle as it is the source of 86% of global evaporation.
Glen Canyon Dam is a concrete arch-gravity dam in the southwestern United States, located on the Colorado River in northern Arizona, near the city of Page. The 710-foot-high (220 m) dam was built by the Bureau of Reclamation (USBR) from 1956 to 1966 and forms Lake Powell, one of the largest man-made reservoirs in the U.S. with a capacity of more than 25 million acre-feet (31 km3). The dam is named for Glen Canyon, a series of deep sandstone gorges now flooded by the reservoir; Lake Powell is named for John Wesley Powell, who in 1869 led the first expedition to traverse the Colorado River's Grand Canyon by boat.
The Governor Edmund G. Brown California Aqueduct is a system of canals, tunnels, and pipelines that conveys water collected from the Sierra Nevada Mountains and valleys of Northern and Central California to Southern California. Named after California Governor Edmund Gerald "Pat" Brown Sr., the over 400-mile (640 km) aqueduct is the principal feature of the California State Water Project.
Lake Oroville is a reservoir formed by the Oroville Dam impounding the Feather River, located in Butte County, northern California. The lake is situated 5 miles (8 km) northeast of the city of Oroville, within the Lake Oroville State Recreation Area, in the western foothills of the Sierra Nevada. Known as the second-largest reservoir in California, Lake Oroville is treated as a keystone facility within the California State Water Project by storing water, providing flood control, recreation, freshwater releases to assist in controlling the salinity intrusion into the Sacramento-San Joaquin Delta and protecting fish and wildlife.
New Melones Dam is an earth and rock filled embankment dam on the Stanislaus River, about 5 miles (8.0 km) west of Jamestown, California, United States, on the border of Calaveras County and Tuolumne County. The water impounded by the 625-foot-tall (191 m) dam forms New Melones Lake, California's fourth-largest reservoir, in the foothills of the Sierra Nevada east of the San Joaquin Valley. The dam serves mainly for irrigation water supply, and also provides hydropower generation, flood control, and recreation benefits.
The Stanislaus River is a tributary of the San Joaquin River in north-central California in the United States. The main stem of the river is 96 miles (154 km) long, and measured to its furthest headwaters it is about 150 miles (240 km) long. Originating as three forks in the high Sierra Nevada, the river flows generally southwest through the agricultural San Joaquin Valley to join the San Joaquin south of Manteca, draining parts of five California counties. The Stanislaus is known for its swift rapids and scenic canyons in the upper reaches, and is heavily used for irrigation, hydroelectricity and domestic water supply.
The California State Water Project, commonly known as the SWP, is a state water management project in the U.S. state of California under the supervision of the California Department of Water Resources. The SWP is one of the largest public water and power utilities in the world, providing drinking water for more than 27 million people and generating an average of 6,500 GWh of hydroelectricity annually. However, as it is the largest single consumer of power in the state itself, it has a net usage of 5,100 GWh.
Folsom Lake is a reservoir on the American River in the Sierra Nevada foothills of California, United States. Folsom Lake with its surrounding Folsom Lake State Recreation Area is one of the most visited parks in the California park system.
Folsom Dam is a concrete gravity dam on the American River of Northern California in the United States, about 25 mi (40 km) northeast of Sacramento. The dam is 340 ft (100 m) high and 1,400 ft (430 m) long, flanked by earthen wing dams. It was completed in 1955, and officially opened the following year.
Auburn Dam was a proposed concrete arch dam on the North Fork of the American River east of the town of Auburn, California, in the United States, on the border of Placer and El Dorado Counties. Slated to be completed in the 1970s by the U.S. Bureau of Reclamation, it would have been the tallest concrete dam in California and one of the tallest in the United States, at a height of 680 feet (210 m) and storing 2,300,000 acre-feet (2.8 km3) of water. Straddling a gorge downstream of the confluence of the North and Middle Forks of the American River and upstream of Folsom Lake, it would have regulated water flow and provided flood control in the American River basin as part of Reclamation's immense Central Valley Project.
Water resources management is a significant challenge for Mexico. The country has in place a system of water resources management that includes both central (federal) and decentralized institutions. Furthermore, water management is imposing a heavy cost to the economy.
California's interconnected water system serves almost 40 million people and irrigates over 5,680,000 acres (2,300,000 ha) of farmland. As the world's largest, most productive, and potentially most controversial water system, it manages over 40 million acre-feet (49 km3) of water per year. Use of available water averages 50% environmental, 40% agricultural and 10% urban, though this varies considerably by region and between wet and dry years. In wet years, "environmental" water averages 61%, while in dry years it averages 41%, and can be even lower in critically dry years.
The American River is a 30-mile-long (50 km) river in California that runs from the Sierra Nevada mountain range to its confluence with the Sacramento River in downtown Sacramento. Via the Sacramento River, it is part of the San Francisco Bay watershed. This river is fed by the melting snowpack of the Sierra Nevada and its many headwaters and tributaries, including its North, Middle, and South Forks.
New Exchequer Dam is a concrete–faced, rock-fill dam on the Merced River in central California in the United States. It forms Lake McClure, which impounds the river for irrigation and hydroelectric power production and has a capacity of more than 1,000,000 acre-feet (1.2 km3). The Merced Irrigation District (MID) operates the dam and was also responsible for its construction.
Water resources management in El Salvador is characterized by difficulties in addressing severe water pollution throughout much of the country's surface waters due to untreated discharges of agricultural, domestic and industrial run off. The river that drains the capital city of San Salvador is considered to be polluted beyond the capability of most treatment procedures.
Nacimiento Dam is a dam on the Nacimiento River about 10 miles (16 km) northwest of Paso Robles, California in the United States. The primary purpose of the dam is to provide groundwater recharge for agriculture in Monterey County and northern San Luis Obispo County supported by the Salinas Valley aquifer, as well as flood control, domestic water supply, and hydropower. It forms Lake Nacimiento, popular for boating, fishing and camping, and known locally as the "Dragon Lake" due to its shape.
Flooding in 2017 affected parts of California in the first half of the year. Northern California saw its wettest winter in almost a century, breaking the record set in 1982–83. The same storm systems also flooded parts of western Nevada and southern Oregon. The damage was estimated at $1.55 billion ($1,926,663,046 today), including damage to California roads and highways estimated at more than $1.05 billion.
The 2011–2017 California drought persisted from December 2011 to March 2017 and consisted of the driest period in California's recorded history, late 2011 through 2014. The drought wiped out 102 million trees from 2011 to 2016, 62 million of those during 2016 alone. The cause of the drought was attributed to a ridge of high pressure in the Pacific Sea—the "Ridiculously Resilient Ridge"—which often barred powerful winter storms from reaching the state.
In October, we finished one of the driest three-year periods in our state's history, and then just last month, we experienced what is probably the wettest three weeks in our history.
"Scientists are noticing that in the past 25 years the world seems to be getting more La Niñas than it used to…"
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