Human Activity And The Rise Of Polluted Runoff

Stormwater runoff is one of the greatest threats to clean water in the US. When it rains, water runs off roofs and driveways into the street, picking up fertilizer, oil, pesticides, dirt, bacteria, and other pollutants as it makes its way through storm drains and ditches to our streams, rivers, lakes, and oceans. This polluted runoff has caused serious damage to bodies of water across the US, with states reporting that nonpoint source pollution is the leading cause of water quality problems. While there are many sources of stormwater pollution, this paragraph will focus on the activity that has caused the greatest increase in polluted runoff.

Urbanisation

The impact of urbanisation on polluted runoff is evident in the deterioration of surface water quality in many locations. Urban stormwater carries pollutants such as road salts, oil, grease, chemicals, and debris from impermeable surfaces into waterways. This has led to the closure of shellfish growing areas due to water pollution, impacting the productivity of these areas. Urban runoff also affects the health of waterways, with pollutants having harmful effects on drinking water supplies, recreation, fisheries, and wildlife.

In addition to the physical changes in the landscape, urbanisation brings about changes in land use that contribute to polluted runoff. The conversion of rural areas to urban activities can lead to increased stormwater pollution, as unmanaged stormwater runoff from urban areas enters nearby water bodies without proper treatment. This has resulted in serious damage to streams, lakes, and estuaries, with a significant impact on water quality.

To mitigate the effects of urbanisation on polluted runoff, it is essential to implement effective pollution mitigation tools. Source controls have been recognised as a successful method to reduce pollution, but they require a comprehensive understanding of the pollution sources. Residents and communities also play a crucial role in preventing stormwater runoff by adopting small changes in their daily activities, such as reducing car usage, properly disposing of waste, and maintaining vehicles to prevent fluid leaks.

Furthermore, urbanisation has led to the development of green infrastructure initiatives to manage polluted runoff. Low-impact development techniques, such as green roofs, permeable pavements, and vegetated land covers, help reduce runoff and improve water quality. Implementing these practices can lower building energy costs, reduce construction costs, and create habitats for birds, insects, and pollinators. By adopting these strategies, communities can effectively minimise the impact of urbanisation on polluted runoff and protect their local water sources.

Vehicular transportation

Transportation, including vehicular activities, is a major source of pollution that significantly contributes to the deterioration of surface water quality. This is particularly evident in urban and suburban areas, where the land surface is mostly covered by buildings, pavement, and compacted landscapes that increase runoff. As the runoff moves, it picks up and carries pollutants, such as fertilizers, pesticides, dirt, bacteria, and other toxins, into nearby lakes, rivers, wetlands, and coastal waters.

To mitigate the impact of vehicular transportation on polluted runoff, it is essential to adopt sustainable practices. This includes properly maintaining vehicles to prevent fluid leaks, recycling used oil and other fluids, and choosing commercial car washes or washing cars on the lawn to prevent contaminated water from entering storm drains. Reducing vehicle usage by opting for public transportation, carpooling, or biking can also help lower the amount of polluted runoff.

Furthermore, the impact of vehicular transportation on water pollution extends beyond runoff. Vehicle emissions, such as nitrogen oxides (NOx) and particulate matter, contribute to air pollution, which then becomes a source of atmospheric deposition, another major contributor to stormwater pollution. Therefore, addressing vehicular transportation-related activities is crucial in combating polluted runoff and improving water quality.

Atmospheric deposition

The burning of fossil fuels and various industrial activities, such as fuel combustion and agricultural processes, release sulfur and nitrogen compounds into the atmosphere. These compounds mix with water particles, forming a weak acid. As a result, when it rains, the water becomes polluted with these acidic compounds, creating what is known as acid rain. Acid rain has detrimental effects on marine habitats such as rivers and lakes, harming aquatic life.

In the context of polluted runoff, atmospheric deposition plays a crucial role. As the runoff moves, it picks up and carries pollutants, including those introduced by atmospheric deposition, into lakes, rivers, wetlands, and coastal waters. This nonpoint source pollution is challenging to manage as it originates from numerous small, individual sources within a watershed.

To address the problem of polluted runoff caused by atmospheric deposition, it is essential to implement measures that reduce the release of pollutants into the atmosphere. This includes regulating emissions from industrial and agricultural activities and adopting cleaner technologies. Additionally, communities can play a vital role in reducing runoff by properly managing waste, maintaining vehicles, and reducing impervious surfaces to minimize the flow of polluted water into nearby water bodies.

Industrial and sewage treatment plants

While it is challenging to pinpoint the activity that has caused the most significant increase in polluted runoff, industrial and sewage treatment plants are significant contributors. These facilities are designed to treat wastewater, which includes sewage and industrial effluents, before releasing it back into the environment. However, the treatment processes can sometimes fall short, leading to polluted runoff.

Industrial Wastewater Treatment

Industrial wastewater is generated from manufacturing or chemical processes, containing various contaminants that require specialised treatment. The complexity of treating industrial wastewater varies depending on the industry and the specific processes involved. For instance, the treatment of wastewater from a chemical plant may differ significantly from that of a food processing facility.

One of the primary challenges in treating industrial wastewater is the presence of toxic substances and pollutants. These can include heavy metals, chemicals, oils, and other hazardous materials. In some cases, industrial wastewater may also contain high levels of nutrients, such as nitrogen and phosphorus, which can lead to nutrient pollution if not properly treated.

Sewage Treatment Plants

Sewage treatment plants, also known as wastewater treatment plants, are responsible for treating domestic sewage, which includes wastewater from homes and businesses. Domestic sewage carries used water from residential and commercial sources, along with human waste, food waste, and soaps or detergents.

One issue with sewage treatment plants is their potential to become overloaded during heavy precipitation or storm events. This is particularly common in older cities with combined sewer systems, where stormwater and domestic sewage share the same pipes. During intense rainfall, the system can become overwhelmed, resulting in a combined sewer overflow (CSO). This leads to the discharge of untreated or partially treated sewage and stormwater directly into nearby water bodies, contributing to polluted runoff.

Furthermore, sewage treatment plants may also face challenges in effectively removing all contaminants. Certain pollutants, such as pharmaceuticals and personal care products increasingly found in domestic wastewater, can be difficult to eliminate entirely. In addition, the release of treated sewage into local water bodies can still introduce nutrients like nitrogen and phosphorus, contributing to nutrient pollution over time.

Combined Impact on Polluted Runoff

Both industrial and sewage treatment plants play a significant role in managing wastewater and reducing pollution. However, their limitations and challenges can lead to polluted runoff in various ways:

• Inadequate Treatment: Industrial wastewater may not receive the specialised treatment required to eliminate all contaminants, especially in cases where treatment plants lack the necessary equipment or technology.
• Overflow Events: Combined sewer systems in urban areas are prone to overflow during heavy rainfall, resulting in the discharge of untreated or partially treated sewage and stormwater into nearby water bodies.
• Nutrient Pollution: While treatment plants remove many pollutants, the release of treated sewage can still introduce nutrients like nitrogen and phosphorus, contributing to nutrient pollution in local waterways over time.
• Toxic Substances: Industrial wastewater containing toxic substances, if not properly treated, can introduce hazardous chemicals, heavy metals, and other pollutants into the environment, impacting aquatic ecosystems and water quality.
• Maintenance and Optimisation: Sewage treatment plants require regular maintenance and optimisation to function effectively. Neglecting these aspects can lead to system failures and the release of untreated sewage.

Agricultural activities

Fertilizers, pesticides, and manure are essential for crop production, but their excessive or improper use can have detrimental effects on the environment. When it rains, the water runs off fields and carries these chemicals into nearby streams, rivers, and lakes. This process, known as agricultural runoff, leads to the contamination of water sources and poses risks to aquatic life and human health. The pollutants in agricultural runoff can cause excessive algal growth, known as algal blooms, which can deplete oxygen levels in the water, creating hypoxic conditions harmful to fish and other aquatic organisms.

Additionally, agricultural activities can contribute to soil erosion, further degrading water quality. Eroded soil, rich in sediments, can smother aquatic ecosystems, destroying breeding areas and damaging coastal ecosystems, including coral reefs. The excessive sedimentation from erosion can have far-reaching consequences for marine life and the overall health of water bodies.

To mitigate these issues, farmers can adopt soil and water conservation practices. Implementing techniques such as targeted fertilizer and manure application through soil testing and crop-specific calibration can help minimize runoff. Using drip irrigation instead of furrow irrigation reduces water loss and allows for better control of pesticide and nutrient application. Storing livestock manure in designated areas, such as lagoons or covered stockpiles, can also minimize the risk of runoff. By employing these conservation practices, farmers can play a crucial role in protecting water quality and preserving the health of aquatic ecosystems.

Furthermore, initiatives like the National Water Quality Initiative (NWQI) provide guidance and support to farmers in addressing the challenges of polluted runoff. By working together and adopting sustainable practices, agricultural communities can help reduce the impact of agricultural activities on water quality and ensure the long-term health of our precious water resources.

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