Protecting Our Water Sources: Preventing Groundwater Pollution

Groundwater is a valuable natural resource that provides drinking water for over half of the world's population and is used for irrigation in most farmlands. However, it is vulnerable to both overuse and contamination by pollutants such as gasoline and pesticides. As groundwater exists underground in the fractures and spaces between rocks and soil, it is often out of sight and out of mind, making it difficult to manage and protect. To prevent groundwater pollution, it is crucial to address the root causes, such as human activities that release chemicals and pollutants, and agricultural practices that contribute to groundwater depletion and pollution. Effective prevention strategies include careful planning of well locations, implementing spill containment measures, adopting ecological agriculture, and strengthening groundwater governance through education and accessible scientific information.

How to prevent groundwater pollution

Reduce chemical use, especially pesticides, gasoline and fertilisers

Reducing chemical use is a crucial step in preventing groundwater pollution. Here are some ways to reduce the use of pesticides, gasoline, and fertilisers:

Pesticides

• Read the labels: Always follow the instructions and requirements on pesticide product labels. Be aware of any products that have the potential to contaminate groundwater and keep them away from storm drains and gutters.
• Proper storage and disposal: Store and dispose of pesticides properly to prevent leaks and corrosion. Never pour pesticides down drains or sewers.
• Minimise usage: Only use pesticides when necessary to minimise potential harm to wildlife, including birds, beneficial insects, and fish.
• Landscaping techniques: Adopt landscaping techniques that increase native habitats, reducing the need for pesticides.
• Conservation buffers: Use conservation buffers, such as those outlined by the USDA's NRCS, to trap and degrade pesticides.
• Integrated Pest Management (IPM): Adopt environmentally sensitive approaches to pest management in agriculture, as recommended by the EPA.

Gasoline

• Clean Air Act: Support and advocate for legislation like the Clean Air Act, which aims to reduce air pollution by requiring engines and fuels to produce fewer emissions.
• Emissions-control devices: Equip vehicles with emissions-control devices, such as catalytic converters, to reduce the release of toxic air pollutants.
• Cleaner engines: Transition to cleaner-burning engines and alternative fuels that produce fewer emissions, such as electric or hybrid vehicles.
• Alternative transportation: Opt for alternative means of transportation whenever possible, such as walking, cycling, or using public transportation, to reduce gasoline consumption.

Fertilisers

• Proper application: Apply fertilisers in the proper amounts, at the right time of year, and with suitable methods to reduce the amount reaching water bodies.
• Conservation drainage practices: Implement subsurface tile drainage and other conservation drainage techniques to manage water movement and reduce nutrient loads, such as modifying drainage systems and using woodchip bioreactors.
• Ground cover: Maintain year-round ground cover by planting cover crops or perennial species to prevent soil erosion and nutrient loss into waterways.
• Field buffers: Plant trees, shrubs, and grasses along the edges of fields, especially those bordering water bodies, to act as natural buffers.
• Conservation tillage: Reduce the frequency and intensity of tilling fields to improve soil health, reduce erosion, and decrease the chance of nutrients reaching waterways.

Improve well location and management

Locating and managing wells properly is crucial to preventing groundwater pollution. When planning a well location, it is important to consider the well's position in relation to surface drainage and groundwater flow. A well downhill from a livestock yard, a leaking tank, or a septic system is more likely to be contaminated than one on the uphill side of these pollution sources. Therefore, it is advisable to place wells uphill from potential pollution sources.

The depth of the well also matters. Shallow wells draw from groundwater near the land surface, which may be directly impacted by nearby activities. The deeper the well, the greater the protection as the groundwater supplying it has likely travelled a long distance underground over a long time. Thick clay soils, for instance, can prevent contamination by blocking contaminants from reaching the water table.

To reduce the risk of groundwater contamination, it is essential to keep potential sources of pollution away from the well. For example, silos located too close to a well should have a system to collect any juices draining from freshly ensiled forage. Concrete curbs can also be installed to direct livestock yard runoff away from the well. Similarly, short-term manure stacks, which can contaminate wells with bacteria or nitrates, should be placed away from the well, preferably on clay soil or a concrete slab, and protected from rain.

Other management practices include relocating traffic areas, chemical or gasoline storage areas, and pesticide mixing tanks away from the well. Upgrading and properly managing septic systems are also crucial. Anti-backflow devices should be used when filling pesticide sprayer tanks to prevent chemicals from flowing back into the well and contaminating groundwater. Additionally, regular inspections of high-risk areas can help identify potential leaks or accidents before they occur, and an emergency response plan can ensure that spills are properly managed.

Adopt ecological agriculture

Agriculture is a leading cause of groundwater pollution. The use of pesticides, fertilisers, and manure can lead to nutrient loss, soil erosion, and bacteria, which can then contaminate water sources.

Ecological agriculture is a form of food production that adopts a cradle-to-cradle approach, aiming to create a circular economy where no manufacturing processes or products emit chemicals harmful to water. This method of farming can help to prevent groundwater pollution and protect water sources.

Farmers can adopt ecological agriculture by implementing the following practices:

• Nutrient management: Applying the right amount of nutrients (fertiliser and manure) at the right time of year, using the correct method and placement. This ensures that nutrients are fully utilised by plants, reducing the risk of excess nutrients contaminating water sources.
• Conservation drainage: Modifying drainage systems to manage water movement through soils. This includes strategies such as subsurface tile drainage, woodchip bioreactors, saturated buffers, and drainage ditch system modifications to reduce nutrient loads while maintaining adequate drainage.
• Year-round ground cover: Planting cover crops or perennial species to prevent periods of bare ground, reducing the risk of soil erosion and nutrient loss during vulnerable times.
• Collaboration and leadership: Farmers can take a leadership role by engaging with state governments, conservation groups, educational institutions, and community groups to reduce nutrient pollution. Collaboration across watersheds is vital to protecting water quality.

By adopting ecological agriculture and implementing these specific practices, farmers can help prevent groundwater pollution, protect water sources, and contribute to a more sustainable food production system.

Strengthen groundwater governance

Groundwater is a crucial resource that provides drinking water to over half of the world's population. It is also essential for irrigation in most farmlands. However, it is often taken for granted because it is hidden from our sight. As a result, human activities have led to groundwater depletion and pollution. Strengthening groundwater governance is essential to address this issue and ensure the sustainability of this vital resource. Here are some measures that can be implemented to strengthen groundwater governance:

• Improve knowledge and accessibility: Groundwater governance can be strengthened by improving knowledge and understanding of groundwater science. Initiatives such as the Groundwater Project can help make information more accessible to the public and raise awareness about the importance of groundwater protection.
• Apply the Precautionary Principle: Recognizing that groundwater depletion and pollution are often unintended consequences of human activities, the Precautionary Principle (PP) should be the guiding principle for groundwater governance. This means taking a proactive approach to prevent potential harm to groundwater, even in the face of scientific uncertainty.
• Shift to ecological agriculture: Modern chemical agriculture is a significant contributor to groundwater depletion and pollution. Governments should promote ecological agriculture, which is a form of cradle-to-cradle production applied to food. This approach ensures that no harmful chemicals are released into the groundwater during the production process.
• Impose taxes and penalties: Governments should impose taxes or penalties on agricultural practices that contribute to groundwater pollution, such as the excessive use of pesticides and fertilizers. Eliminating government subsidies that encourage unsustainable agricultural practices can also help reduce groundwater pollution.
• Establish effective monitoring: Modern monitoring methods, such as those for groundwater levels and hydrochemistry, should be utilized with data transparency. This will help identify potential risks and ensure that groundwater resources are adequately protected.
• Collaborate with businesses: Governments should work closely with businesses to identify site-specific ways to limit the potential for groundwater contamination. Providing free spill containment supplies and offering assessments can help ensure that businesses operate in ways that protect groundwater.

Implement remediation methods

Remediation methods can be implemented to treat contaminated groundwater and prevent future pollution. There are two types of groundwater remediation: in-situ (on-site) and ex-situ (off-site). In-situ remediation, also known as bioremediation, involves introducing microorganisms to the groundwater that destroy or detoxify inorganic and organic contaminants. The water is treated precisely where it is located. This method is based on the understanding that groundwater exists underground in fractures and spaces between rocks and soil, known as aquifers. Bioremediation is a natural process that can be enhanced by human activity to achieve faster and more effective results.

On the other hand, ex-situ remediation, often referred to as "pump and treat," involves physically pumping out the contaminated groundwater using a vacuum pump. The water is then purified off-site before being returned to the aquifer. This method is more invasive and requires the expertise of a professional water remediation company. It is also a costly process, often ranging from thousands to millions of dollars, and the water quality must be monitored for years afterward.

While remediation methods are crucial for addressing existing groundwater pollution, it is important to prioritize preventing contamination in the first place. This can be achieved through a combination of improved governance, education, and sustainable practices, as outlined in the previous sections. By focusing on prevention and remediation, we can effectively protect and preserve this valuable natural resource.

Frequently asked questions