Protecting The Potomac: Strategies To Reduce Pollution

The Potomac River is the second-largest tributary of the Chesapeake Bay, flowing for over 380 miles through forests, farms, and cities. It is a vital source of fresh drinking water for five million people and a habitat for wildlife. Despite significant improvements over the past decade, the Potomac River's health has recently declined, slipping from a B to a B- grade. The primary causes of pollution are toxic excess nutrients from fertilizers, pesticides, and street oils, as well as silt and sediment from erosion, E. coli from diluted sewage, and bacteria from algal blooms. To restore the river's health, it is crucial to address these issues and implement measures such as investing in clean water, protecting forests, and strengthening laws that safeguard waterways.

Reduce urban runoff by improving rainwater absorption

Urban runoff is a major source of pollution in the Potomac River. As natural surfaces like forests are replaced with impervious surfaces like pavement, rainwater collects pollutants such as sediment, bacteria, oils, metals, and other toxins, which are then discharged into waterways. This is a significant issue in highly developed areas with little ground cover, where rainwater is diverted into streams, polluting the water with road chemicals, litter, and other debris.

To reduce urban runoff and improve rainwater absorption, the following strategies can be implemented:

Green Infrastructure

Implementing "green infrastructure" practices such as rain gardens, green roofs, and tree planting in urban areas can help reduce polluted runoff. These practices not only improve rainwater absorption but also provide additional benefits like energy savings, flood reduction, water reuse, and cooler temperatures.

Permeable Pavement

Replacing impervious surfaces with permeable pavement allows rainwater to infiltrate and be absorbed by the ground, reducing the volume of stormwater runoff. This can be particularly effective in highly developed areas where large amounts of rainwater flow into storm sewers and overwhelm the system, resulting in combined sewer overflows that dump untreated wastewater into waterways.

Rain Gardens and Retention Ponds

Rain gardens and retention ponds can be strategically placed to capture and treat rainwater before it enters the stormwater system. These natural features act as onsite surge tanks, removing pollutants through filtration and bioretention processes while also providing habitat for wildlife.

Stormwater Retention Tunnels

Constructing stormwater retention tunnels can help to capture and store excess rainwater, reducing the volume of runoff entering waterways. These tunnels can be designed to redirect stormwater to treatment facilities or natural areas for further filtration and absorption.

Stream Restoration and Buffers

Restoring streams and their natural buffers, including streamside forests, can improve rainwater absorption and filtration. Trees and vegetation act as natural filters, stabilizing stream banks with their root systems and filtering pollutants from rainwater. They also help to shade waterways, keeping water temperatures cool, which is essential for maintaining healthy aquatic ecosystems.

Public Policy and Planning

Urging local leaders and planners to prioritize conservation and forward-thinking development plans is crucial. This includes creating and enforcing regulations that protect natural areas, streamside buffers, and tree cover. Additionally, implementing smart planning approaches that embrace mixed-use development, protect forested and public lands, and incorporate nature-based solutions can help reduce urban sprawl and its associated pollution.

Improve farming practices to reduce agricultural pollution

Improving farming practices is essential to reducing agricultural pollution in the Potomac River. Here are some detailed and direct instructions for farmers in the region to help achieve this goal:

Implement Nutrient Management Techniques

Farmers should ensure that they are applying the correct amount of fertiliser at the right time of the year, using the appropriate method and placing it in the right spot. Accuracy in fertiliser application can significantly reduce fertiliser runoff from fields, which can affect other farms, livestock, and water supply. This practice can also help decrease nutrient losses to the air, as nitrogen can be lost from fields in the form of nitrogen-based compounds like ammonia and nitrogen oxides, which are harmful to aquatic life and contribute to greenhouse gas emissions.

Add Conservation Buffers

By planting trees, shrubs, and grasses along the edges of fields, farmers can create conservation buffers that help catch and filter runoff. These buffers are especially beneficial for fields bordering waterways. In addition to preventing runoff, these buffers can also provide habitat for wildlife and improve the aesthetic value of the farmland.

Control Livestock Access to Waterways

Farmers should install fencing along streams, rivers, and lakes to restrict livestock access. This practice helps restore stream banks and prevents excess nutrients and waste from entering the water. It is important to ensure that livestock have alternative sources of fresh water to meet their needs.

Adopt Conservation Drainage Practices

Subsurface tile drainage is commonly used in the Midwest to manage water movement through soils. While this practice is important for crop production, it can contribute to nutrient runoff. Conservation drainage strategies, such as modifying drainage system design, woodchip bioreactors, saturated buffers, and changes to the drainage ditch system, can help reduce nutrient loads while maintaining adequate drainage.

Ensure Year-Round Ground Cover

Farmers can plant cover crops or perennial species to prevent periods of bare ground on farm fields, making them more susceptible to erosion and nutrient loss. This practice improves soil health and reduces the risk of nutrients reaching waterways.

Engage in Watershed Efforts

Farmers should collaborate with a diverse range of stakeholders, organisations, and community groups across the entire watershed. By taking on leadership roles in these efforts, farmers can contribute to reducing nutrient pollution in water and air. This collaboration can involve engaging with state governments, conservation groups, educational institutions, and non-profit organisations.

Protect forests and plant trees to absorb rainwater and filter polluted runoff

Protecting forests and planting trees are essential nature-based solutions for absorbing rainwater and filtering polluted runoff. Trees are nature's best water filters, and their presence is vital to the health of the Potomac River.

Trees play a crucial role in intercepting rainwater before it hits the ground. Their leaves, also known as the canopy, act as a barrier, holding rainwater until it evaporates. This simple yet effective mechanism helps prevent stormwater systems from overflowing and releasing raw sewage into the river. The canopy also provides shade, keeping water temperatures cool and inhibiting the growth of toxic algae blooms, which can be harmful to both people and animals.

The roots of trees are equally important. They help to absorb and filter pollution from rainwater before it flows into the river. Additionally, tree roots provide a stable base for soil along stream and riverbanks, preventing shoreline erosion and reducing excess sediment in the water, which can harm aquatic habitats.

Unfortunately, deforestation and development pose significant threats to the health of the Potomac River. When forests are cleared to make way for plazas, parking lots, and housing developments, the land loses its ability to absorb rainwater effectively. This leads to increased runoff, which not only pollutes drinking water sources but also destroys fishing grounds and wildlife habitats.

To combat this issue, it is essential to protect large areas of woodland and create forward-thinking conservation plans. This includes urging city and county planners to consider the environmental impact of their decisions and supporting organisations like the Potomac Conservancy, which works with communities to safeguard riverside forests.

In addition to protecting existing forests, planting trees is another powerful tool in the fight to reduce pollution in the Potomac River. By selecting and planting local tree species, communities can help absorb rainwater, filter polluted runoff, and stabilise stream banks. Many municipalities offer free trees and even provide assistance with planting and maintenance, making it easier for residents to get involved.

Improve sewage treatment and separate stormwater and sewage pipes

The Potomac River has been a target for pollution clean-up efforts since 1956, when the United States Public Health Service was granted authority to proceed against interstate water pollution. Despite these efforts, the river remains polluted due to "a hundred years of underestimates, bad decisions, and outright mistakes", according to Eugene Jensen, regional director of the Federal Water Quality Administration.

One of the main ways to reduce pollution in the Potomac is to improve sewage treatment and separate stormwater and sewage pipes. Here are some ways to do this:

Improve Sewage Treatment

• DC Water, the city's water and sewer authority, is responsible for treating wastewater from the District of Columbia, Maryland, and Virginia at the Blue Plains Advanced Wastewater Treatment Plant, the largest plant of its kind in the world.
• On an average day, close to 300 million gallons of raw sewage flow into the Blue Plains plant to be treated. After treatment, the cleaned water flows into the Potomac River, which eventually leads to the Chesapeake Bay.
• DC Water is under strict requirements to reduce the amount of nitrogen and phosphorus in the cleaned water discharged into the Potomac. They have implemented innovative technologies and continue to improve their wastewater treatment processes to better serve the community and protect the environment.
• The Blue Plains plant should aim to remove upwards of 90% of the principal pollutants, including oxygen-absorbing matter, phosphates, and nitrates, which stimulate algae growth.
• The plant should also ensure that the amount of live bacteria in the river is within safe levels. Coliform counts in the Potomac should not exceed 1,000 coliform organisms per 100 milliliters, as recommended by authorities.
• DC Water should continue to work with the EPA and local environmental groups to meet pollution reduction goals and improve water quality.

Separate Stormwater and Sewage Pipes

• Combined sewage systems (CSS) carry both sanitary sewage and stormwater. During dry weather, the sewage is channelled to the sewage treatment plant, but when there is heavy rainfall, pipes in a CSS can quickly overflow, resulting in combined sewer overflows (CSOs).
• CSOs divert untreated sewage and stormwater away from the sewage plant and discharge it into local waterways, posing a substantial risk to water quality due to the toxic materials and debris that are released.
• To mitigate this issue, cities can adopt green infrastructure (GI) technologies such as bioretention gardens, permeable pavements, green roofs, and constructed wetlands, which attempt to mimic the natural filtration of water to decelerate rainwater entering sewage and filter debris and toxic substances.
• In addition to GI, storage tunnels can be constructed to handle excess water from overflows. These tunnels have conclusive tangible results in combating CSOs.
• By combining grey infrastructure (advanced piping systems) with GI technologies, cities can dramatically reduce and nearly eliminate CSO pollution.

By implementing these measures to improve sewage treatment and separate stormwater and sewage pipes, the Potomac River can move towards becoming clean, swimmable, and safe for recreational activities.

Reduce litter and illegal dumping

To reduce litter and illegal dumping in the Potomac, it is important to address the issue of stormwater runoff, which is the fastest-growing cause of pollution in the river. Stormwater runoff occurs when excess rainwater flows across paved surfaces and carries trash and other debris directly into local streams. One way to mitigate this is by protecting and expanding forested lands, which act as a natural buffer and help to absorb rainwater, reducing the amount of water flowing into the river.

One specific way to achieve this is by urging local decision-makers to support clustered areas for mixed-use development, protect zones for forested and public lands, and invest in nature-based solutions such as rain gardens and permeable pavement. This will help to reduce the amount of paved surfaces and direct trash into designated areas, rather than into the river.

Additionally, individuals can play a role by being mindful of their trash and ensuring that they properly dispose of their waste. This includes bringing reusable items when outdoors, such as water bottles, and picking up any trash that they bring with them. Participating in local trash clean-up events can also help to remove trash and debris from the river and its surrounding areas.

Another way to reduce litter and illegal dumping is by addressing the issue of combined sewer systems, which are commonly found in older urban areas. These systems route sewage and stormwater through the same pipes, and during significant rain events, the pipes can back up, causing a mixture of sewage and stormwater to discharge directly into the river. Upgrading and separating these systems can help to reduce the amount of trash and pollutants entering the river.

Frequently asked questions