Agricultural Pollution: La River's Unseen Danger

The Los Angeles River, which runs for 51 miles from the San Fernando Valley to the Pacific Ocean, has a long history of pollution. Once the primary source of fresh water for the city, the river became so polluted by 1900 that LA began sourcing water elsewhere. Today, the river is still heavily polluted, with over 21 identified pollutants that exceed federal guidelines. While some of these pollutants come from sewage and industrial dumping, the majority can be attributed to stormwater pollution, which results from the high percentage of paved surfaces in LA that prevent rainfall from being absorbed into the ground. Agricultural runoff, along with urban runoff, is a significant contributor to the LA River's water quality issues.

The LA River is subject to five TMDLs that regulate 13 pollutants

The Los Angeles River (LA River) is a 51-mile-long waterway that runs through 11 cities in LA County. The river has been subject to industrial dumping, sewage, and stormwater pollution for over a century. As a result, the LA River is now impaired due to a variety of point and nonpoint sources, with over 21 identified pollutants that exceed federal guidelines.

To address this issue, the LA River is subject to five Total Maximum Daily Loads (TMDLs) that collectively regulate 13 pollutants: ammonia, bacteria, cadmium, copper, nitrate, nitrite, lead, selenium, trash, and zinc. TMDLs are regulatory limits that set the maximum amount of a pollutant allowed to be discharged into an impaired water body. They are established based on pollutant source assessments, human health considerations, and ecosystem toxicity analyses.

The five TMDLs for the LA River take into account the varying levels of pollution along the river's path. The river flows through a mix of residential, commercial, and industrial areas, with dense urban development in its lower section. This has resulted in a complex mixture of pollutant sources, including stormwater runoff, sewage, and industrial waste.

To improve water quality, LA County has implemented Watershed Management Programs (WMPs) and an Enhanced Watershed Management Program (EWMP) to facilitate strategies for TMDL compliance. These programs aim to capture stormwater and urban runoff for treatment, infiltration, or direct use, supporting the designated beneficial uses of the river. While progress has been made, challenges remain in funding and implementing proposed projects to meet water quality targets.

Stormwater runoff is more polluted than sewage and directly flows into the river

Stormwater runoff is a significant environmental concern, particularly in urban areas. It occurs when rainwater flows off roofs, driveways, streets, parking lots, and other developed land, picking up and carrying various pollutants along the way. This polluted water then rushes into nearby gutters, storm drains, streams, rivers, and other water bodies without undergoing treatment.

In the context of the Los Angeles River, stormwater runoff is a major contributor to the river's pollution. The river, which is 51 miles long, flows through 11 cities in LA County and has been heavily impacted by urban development. Due to the high percentage of paved surfaces in LA, estimated at 60%, most rainwater does not get absorbed into the ground but instead becomes runoff that flows directly into the river.

This stormwater runoff is more polluted than sewage. Unlike sewage, which undergoes regulation and monitoring by local governments, stormwater is largely unmanaged and carries a range of harmful pollutants. These pollutants include toxic chemicals from herbicides and lawn fertilizers, as well as grease and engine oil. The concentration of these pollutants in the river poses a significant threat to the aquatic ecosystem and water quality.

The Los Angeles River has been identified as having over 21 pollutants that exceed federal guidelines. These pollutants include ammonia, metals, coliform, trash, scum, algae, oil, pesticides, and volatile organics. The high levels of plastic debris, which often come from packaging, are also of significant concern. The accumulation of these pollutants has detrimental effects on the river's ecosystem and the recreational potential of the river.

Addressing stormwater runoff pollution is a complex task due to the many sources of pollution within the watershed. Efforts to reduce stormwater pollution include implementing water quality plans, capturing stormwater for treatment or infiltration, and improving coordination between the various localities with jurisdiction over the river. Additionally, individual actions, such as maintaining vehicles, properly disposing of hazardous substances, and reducing car usage, can collectively make a significant difference in mitigating stormwater pollution.

The river is impaired by a variety of point and nonpoint sources

The Los Angeles River is a 51-mile-long waterway that runs through 11 cities in LA County. The river is subject to pollution from a variety of point and nonpoint sources. The majority of the river's pollutants can be attributed to stormwater runoff, which is more polluted than sewage due to a lack of regulation and monitoring. As 60% of LA is paved, most rainfall runs off into the river without being absorbed or filtered, carrying pollutants such as toxic chemicals from herbicides, lawn fertilizers, grease, and engine oil.

The river's water quality is further impacted by urban activities, with pollutants such as bacteria, nutrients, oil, grease, trash, and trace metals generated from residential, industrial, and commercial areas. The high number of point source permits in these areas also contributes to the river's impairment. Additionally, agricultural runoff, wastewater treatment, and sewage spills have been identified as sources of pollution.

The LA River has been designated as a bacteria-impaired waterbody, with high bacteria counts detected in its waters. This has raised concerns for the growing number of people who use the river for recreation, including fishing, swimming, and kayaking. To address these issues, the Los Angeles Regional Water Quality Control Board has imposed a bacteria Total Maximum Daily Load (TMDL) to regulate the amount of bacteria allowed in the river.

The river is also subject to five TMDLs that regulate the discharge of 13 pollutants, including ammonia, bacteria, cadmium, copper, nitrate, nitrite, lead, selenium, and zinc. These targets vary depending on the specific location along the river and are based on pollutant source assessments, human health considerations, and ecosystem toxicity analyses. While there have been efforts to improve water quality, challenges remain due to the large number of localities with jurisdiction over the river and insufficient government cooperation.

Bacteria sources include pets, horses and human waste

The Los Angeles River is a 51-mile-long waterway that starts in the San Fernando Valley and empties into the Pacific Ocean. The river has over 21 identified pollutants that exceed federal guidelines, with the majority of these pollutants coming from stormwater runoff.

The Los Angeles Regional Water Quality Control Board has identified several contributors of harmful bacteria to recreational zones along the river, including urban runoff, leaks and flows from wastewater collection systems, illicit connections, and failing septic systems.

Bacteria sources in the LA River include pets, horses, and human waste. Pet waste, in particular from warm-blooded mammals, contains E. coli bacteria, which can be washed into local streams during snowmelt or rainfall and eventually make their way into the river. Similarly, livestock such as horses can be a significant source of E. coli contamination if they have unrestricted access to water or their manure is directly deposited into surface waters.

Human waste can also introduce bacteria into the river. In older communities, sewer systems may combine domestic wastewater with stormwater drainage, and during heavy rainfall events, these systems can become overwhelmed, resulting in the release of untreated wastewater known as Combined Sewer Overflow (CSO).

Recreational use of the river is threatened by poor water quality

The Los Angeles River, which starts in the San Fernando Valley, is 51 miles long and runs through 11 cities in LA County. The river has a history of pollution, with the first Spanish settlers of LA settling on an ecologically vibrant section of the river in 1781. For over a century, the river was the main water source for the city. However, by 1900, industrial dumping and untreated sewage had polluted the river to such an extent that LA began sourcing water elsewhere.

Today, the river is still heavily polluted, with over 21 identified pollutants that exceed federal guidelines. The majority of these pollutants come from stormwater runoff, which is considerably more polluted than sewage due to the lack of regulation. As 60% of LA is paved, most rainfall runs off into the river without being absorbed, carrying with it harmful pollutants such as toxic chemicals from herbicides, lawn fertilizers, grease, and engine oil.

The high levels of pollution in the river have led to it being designated as a bacteria-impaired waterbody by the state. A water quality study by Heal the Bay found that popular recreation spots along the river suffer from very poor water quality, which poses health risks to those who fish, swim, and kayak in its waters. The study also highlighted the need for increased monitoring and public notification about water quality issues.

The poor water quality in the LA River is a result of a variety of factors, including agricultural and urban runoff, leaking underground storage tanks, contaminated groundwater, and sewage spills. The river flows through industrial, residential, and commercial areas, including major refineries and government buildings, which contribute to the high levels of pollution.

The degradation of water quality in the LA River has impacted the beneficial uses of the river, including aquatic life, recreation, groundwater recharge, and municipal water supply. With increasing urbanization and a lack of coordination among relevant stakeholders, it is essential to implement effective pollution reduction initiatives to improve the river's water quality and protect its recreational use.

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