Pollution In The Sacramento River And Hope For Its Future

The Sacramento River is 343 miles long and contains 31% of the water runoff in the state of California. It is a major watershed whose tributaries come from the Sierra Nevadas, Hostas, Cascades, and other mountain ranges in the region. 

The river runs through the agriculturally vibrant Central Valley region and provides water to the residents of north, central, and southern California. The Sacramento River Basin is considered essential to the US food supply. 

Indeed, one-third of all produce grown in the United States come from the Central Valley. Unsurprisingly perhaps, the economy and viability of life in California are intrinsically tied to the Sacramento River. 

Despite the river’s central role in providing energy, food, and water, the National Resource Defense Council notes that the Sacramento is one of the dirtiest rivers in the United States. 

How did the most important river in California become so polluted?


Pollutants in the Sacramento River include methylmercury, microplastics, chemical pesticides from agricultural industries, and sewage overflow that results in elevated E. coli levels. 

In addition to these effluents, the ecological viability of the river is threatened by large scale water infrastructure projects that have served to divert, dam, and irrigate the river for human ends. Combined with the dual obstacles of climate change and invasive species, there are countless environmental challenges that currently plague the Sacramento River region. 


Researchers from the University of California Berkeley found that over 7 trillion microplastics are deposited in the San Francisco Bay each year. 

The material largely comes from the erosion of rubber tires that become swept up in water runoff. Large plastic materials like packaging products and plastic bags have also been found in abundance in the San Francisco Bay. 

A recent study in the Bay area found that a fourth of California’s anchovy, striped bass, and salmon had plastic in their stomachs.


The Sacramento River Valley was the site of the famous 19th century California gold rushes that brought thousands of settlers to the state. 

The Gold Rush had two historic impacts on the trajectory of the Sacramento; methylmercury contamination and habitat loss due to flood control and irrigation projects. 

Mercury levels in the river are dangerously elevated as a result of the mostly shuttered gold mining operations. Mines were dotted all across the Central Valley region. The mercury used in the gold production process was deposited in the river as miners tried to isolate gold deposits. 

Even very small levels of mercury can have long-term, detrimental impacts on wildlife and humans. 

According to the US Geological Service, methylmercury bioaccumulates in fish populations and if consumed, attacks the central nervous system. Mercury poisoning can cause a decline in motor skills, dulling of the senses, and, in extreme cases, death.


The practice of hydrological mining,  whereby pressurized water was concentrated on river banks to expose gold deposits, became common and resulted in large quantities of sediment to flow downriver and raise the river’s altitude. 

The elevated river bed exacerbated the annual flooding in the low-lying plains of the Central Valley. Farmers built successively higher and higher levees to try to ward off floods and control the river’s water flow for their own irrigation. 

This led to the widespread destruction of river forests and increased soil erosion.


Large-scale damming projects and water diversion canals have significantly altered the flow of the Sacramento River. The dams serve to provide energy to the region through hydroelectric generation, divert water to the parched southern regions of the state, and guard against flooding. 

Diversions from the Sacramento River are central to the water supply of the major urban centers of the state, including the Los Angeles and San Francisco metropolitan regions. 

Yet despite their practical features, the dams have significantly altered river currents and deprived estuaries of critical freshwater resources. Faster water flows resulted in sediment erosion along the river banks and threatens the health of ecologically fertile riparian forests. 


The massive installations also precipitated the decline in Chinook salmon spawning and reduced steelhead, starry flounder, and trout populations that once flourished in the river.

Chinook salmon is considered a keystone species that supports ecosystems both inland, on the California shore, and in the Pacific Ocean. Their downturn has impacted everything from migratory birds, to the fishing industry, to orca whale populations out at sea. 

Downstream, more than 90% of San Francisco’s freshwater is diverted before it even makes it out to the ocean. The depletion of freshwater has all but eliminated the smelt fish populations that once numbered in the millions in the Bay.


The Sacramento River is the source of some of the most fertile lands in the continental United States. The river is the crux of the Central Valley, California’s agricultural heartland. The region supports the robust cultivation of wheat, almonds, avocados, corn, and citrus fruits among other mainstay crops

The Central Valley is considered one of the most important agricultural regions in the United States, supporting hundreds of thousands of jobsOne out of every three pieces of produce grown in the US is sourced from the region.  

Consequently, the nature of pollution in the Sacramento River and the diversion of its waters for irrigation, is inextricably intertwined with agricultural practices.

Farmers’ use of chemical pesticides pollute the river and have resulted in reduced water quality. The dirtier water has directly impacted local wildlife in the region as the chemicals threaten aquatic birds, river animals, and regional biodiversity as a whole.

The California Department of Pesticide Regulation reported that over 200 million pounds of agricultural pesticide were used in the Central Valley in 2017. 

In addition to pesticides, irrigation projects used to divert river waters to agricultural operations have damaged the surrounding natural environment. 

Over 80% of water consumption from the Sacramento River is for agricultural purposes. Such large scale water use in the North has led to criticisms of waste by more drought-conscious southern residents of the state. 


A confluence of social issues stemming from homelessness, park recreation, and international trade have created even more environmental challenges for the Sacramento River. 

Homeless encampments and population growth in the urban stretch of the American river by Sacramento have led to a spike in plastic litter pollution

More than 100 invasive species have been identified by the Sacramento River Watershed Program. Invasive species compete with native fauna and wildlife, consume disproportionate quantities of precious water resources, and sometimes provide fodder for wildfires. 

Meanwhile recreational hunting and fishing had to be reeled back in recent years as overfishing weakened already overtaxed salmon, trout, and steelhead populations.

Cross-contamination of sewage and precipitation runoff continues to plague the water of the Sacramento River. Ailing sewage systems and inadequate hydrological infrastructure often lead to sewage overflow that drains into the river basin.


Homeless encampments along the banks of the American and Sacramento Rivers have contributed to increased fecal and excrement dumping. Without public restroom facilities or adequate housing, many homeless residents resort to disposing of their waste directly into the river. 

Local reports have found dangerously high levels of E. coli present in the water. A recent sampling by the administration indicated that 13 out of 15 locations along the Sacramento had E. coli that exceeded federal safety guidelines seven times over.

E. coli poses an imminent risk of spreading illnesses to those who swim and fish in river waters and can cause symptoms that range from diarrhea to abdominal cramping and respiratory issues.


Indigenous communities have also been negatively impacted by the large scale water projects along the Sacramento. 

The Winnemem-Wintu peoples were cleared out of their tribal lands and relocated by the federal Shasta Dam project in the 1940s and they continue to fight efforts to raise the dam today. 


Multiple administrative agencies have authority over the Sacramento River and their jurisdiction is fragmented along the length of the river. Large portions of the upper valley is managed by the US Forest Service

Much of the northern region is important for commercial lumber activity. Arid sections in the north are administered by the Bureau of Land Management. 

There are two water authorities that govern the myriad dams that dot the Sacramento River and its tributaries including the American, Yuba, and Feather rivers

The Central Valley Project is federally managed while the State Water Project is managed by the state of California. The Central Valley is dotted by 2 million acres of private agricultural landholdings. The majority of the 2.2 million residents of the Sacramento Valley live in the Sacramento region and its surrounding areas.


Several initiatives by the administration have been founded to address the various environmental challenges facing the Sacramento River. 

Many of the programs have been focused on restoring the populations of anadromous fish which were once plentiful in the Sacramento River Basin. 

For instance, the California Department of Fish and Game, operates a Heritage and Wild Trout Program focused on replenishing steelhead trout in the upper Sacramento. They note that Salmon hatcheries keep the Chinook species on a vital lifeline, as natural levels have come dangerously low to destroying the already endangered species.


To address the enormous issue of plastic pollution and waste in the river, the California state legislature considered SB 54, “The Circular Economy and Pollution Reduction Act”

If enacted, the act would require plastic container manufacturers to ensure that by 2030 all single-use disposable products were made of recyclable or disposable materials. 

Regarded as the most environmentally ambitious proposal of the 2019 legislative cycle, the act became stalled in the assembly by September without passage. 


To address the environmental damage caused by water diversion and damming projects, the California State Water Resources Control Board introduced the Bay-Delta plan in 2018. 

The plan calls for the gradual return of natural river waters into estuaries and the reduction of water diversions in order to restore the depleted San Francisco Bay. 

Additionally, the US Geological Service has conducted surveys of mercury contamination hotspots through the Bear-Yuba Project, identifying areas in need of crucial cleanups to prevent mercury pollution.


In 1988, the Nature Conservancy pioneered the Sacramento River Project. As the largest forest restoration program in US history at the time, the initiative set out to restore the riparian (riverside) forests which had been reduced to 2% of their original cover. 

By planting over a million tree seedlings that are native to the river basin, the initiative has seen the resurgence of natural wildlife and the basin now supports over 250 native species. 

The Sacramento Watershed Program brings together experts from universities, administrative agencies, and the private sector in order to coordinate preservation efforts.

Additionally, the Nature Conservancy was central to the establishment of the Sacramento River Wildlife Refuge which provides a safe haven to migrating bird species. 

The American River Foundation leads monthly river clean-ups by homeless encampments near the state capitol, trying to curb the scourge of plastic litter in river waters. 

Finally, organizations like the San Francisco Baykeeper, the Environmental Defense Fund, and Save the Bay have been leading activists in the fight for stronger environmental protections for the San Francisco Bay area.


Although significant work has been done to address pollution and environmental issues present in the Sacramento Watershed, regulatory and private sector obstacles continue to obstruct meaningful progress. 

  • The highly fragmented nature of water management in California, split between localities, cities, state authorities, and federal agencies, have stymied the collective administration action required to enact effective change around issues of water quality and estuary restoration in the Bay. 
  • The complex water regulatory arena creates uncertainty in regards to responsibility and encourages patchwork solutions instead of a whole of-river approach. 
  • Despite the clear dangers that methylmercury poses to the human body, mercury clean up has proven sluggish because of the thousands of mines in the area and the prevalence of competing water quality authorities. 
  • The private sector and individual citizens also contribute to the river’s degradation. Powerful agricultural interests continue to endorse the use of harmful pesticides that clog the river with dangerous chemicals. A coalition of large farming businesses actively obstructs environmental restoration initiatives, like the Bay-Delta plan, for fear that it may reduce water available for irrigation.

There is a clear need for community-based initiatives to address the gap created by regulatory malaise and staunch polluter interests. 


The pollutants that are present in the Sacramento River – methylmercury, microplastics, and agricultural pesticides – reinforce the need for a circular economic approach rooted in local action. 

  • To the greatest extent, possible products that are used in farming, mining, and service industries should be sourced from recyclable and compostable materials. 
  • Working with agricultural communities will be central to solving the issues along the Sacramento. Minimizing water waste, promoting responsible irrigation, and prioritizing sustainable farming practices are key to reducing pollution and ecological harm in the river. 

Previous Earth5R projects with local farmers in Bangalore has shown the importance of engaging local farming communities and giving them a stake in environmental agency. This is in line with a circular economic


On the question of microplastic pollution, researchers from the San Francisco Estuary Institute point to community solutions like rain gardens. Rain gardens are able to filter out 90% of the incredibly harmful microplastics that accumulate by the trillion in the San Francisco Bay. 

By working with localities to increase rain gardens by roadways, the vast majority of microplastics pollution from vehicle tires could largely be eliminated. Such a solution is especially recommendable considering their efficiency, ease of implementation, and relatively low cost.

By engaging local, state, and private actors in circular economy initiatives, Sacramento will have a cleaner future.

Reach out to Earth5R to know more about solving environmental issues by creating circular economy based sustainability projects


Earth5R is a part of Mithi river clean up project in partnership with United Nations Technology Innovation Labs (UNTIL), Huhtamäki Oyj, VTT Technical Research Centre of Finland, and RiverRecycle.

The goal is to clean the Mithi with innovative tools while raising awareness on waste management and building a circular economy and livelihood based model to restore the Mithi River. 

  • Under this project, Earth5R team will conduct various waste management training for the residential buildings, slums, and industries along the catchment of Mithi River. 
  • Earth5R team will also conduct a large-scale cleanup, waste segregation, and recycling program in the Mithi River area. 
  • The River will be mapped with the help of drones pre and post-project and the data will be analyzed to develop further solutions. 
  • Various research on plastic waste will be conducted to develop innovative solutions that support circular economies. 
  • Children and citizens in various Colleges, Schools, Offices of Mumbai will be mobilized for a solution-based approach to solve the Mithi River plastic pollution problem.

This partnership is one step forward towards sustainable restoration of the Mithi river.


Earth5R is an environmental organization from India with its head office at Mumbai. It works with the NGO sector, Companies and helps them conduct environmental corporate social responsibility (CSR) programs across India. Earth5R specializes in circular economy based projects. Earth5R also offers short term and long term environmental courses.

Earth5R is conducting large-scale online training on COVID 19 Coronavirus prevention, response, management, and self-sustainability. These trainings are conducted on digital platforms in regional languages across India and other countries.

Earth5R’s Global Sustainability Hub is a cross-sector and cross-country collaboration in pursuit of UN Sustainable Development Goals. It is an excellent opportunity for governments and the private sector to engage with communities, use Sustainability-based models to drive economic changes and create social and environmental impact.

Reported by Adam Shaham, edited by Shafa Azzahra