Agriculture & Nonpoint Source Pollution

A kalo patch. The large, flat leaves of each kalo plant stretch out into the sunlight.

Agriculture

Background

EPA’s Agriculture Strategic Plan for the Pacific Southwest Region notes that agriculture is the nation’s leading source of pollution for ground, surface and coastal waters.

Livestock and crop farming practices can discharge pollutants such as fertilizer nutrients, pesticides, herbicides, and fecal bacteria to local waterways. Fallow lands are prone to erosion by wind or water, which leads to sediment pollution in nearby waterways. By implementing best management practices (BMPs), farmers can reduce the amount of polluted runoff from their farms.

A woman in farm clothes harvesting taro in a field and putting the plants into a wagon

Regulatory Requirements

Hawaii Administrative Rules (HAR) Chapter 11-56, Appendix A details new requirements for certain agricultural operators and landowners identified in HAR 11-56-3, “Applicability.” Other forestry and silviculture operators may also be required to follow the listed procedures at the discretion of the Director of Health.

If your operation is considered applicable, you are required to complete the three steps below as well as all other requirements in Appendix A of HAR 11-56:

  • Implement Best Management Practices (BMPs)
  • Register with the Surface Water Protection Branch
  • Develop a Water Pollution Prevention Plan (WPPP)

Even if HAR 11-56-3 does not apply to your operation, all agricultural landowners and operators are encouraged to voluntarily complete these actions to protect water quality.

Best Management Practices

1. Conserve and Protect Water Resources

It is important for farmers to keep rain and irrigation water on their property from entering nearby streams and rivers. By implementing Best Management Practices to control polluted runoff, farmers protect local waterbodies and foster resilience during times of drought and water shortages.

Farmers can conserve water resources by using water more efficiently, improving stormwater interception, reducing water demand, and increasing soil content and soil moisture.

For livestock farmers, it is important to have access to an adequate supply of water that is clean enough to support healthy animals. At the same time, livestock farmers need to be careful to prevent animal wastes from contaminating drinking water sources for livestock and wildlife. Check out the Department of Health’s Guidelines for Management of Livestock Waste.

2. Properly Apply Fertilizers, Pesticides, and Herbicides

Fertilizers, herbicides and pesticides often enter our waterways when applied improperly or excessively. Before fertilizers are applied, a soil test should be administered to determine exactly which, if any, fertilizers should be applied. Fertilizers should be used sparingly and applied when rain is not in the immediate forecast. Organic fertilizers are also known to release nutrients more slowly, allowing a longer treatment of the soil.

Pesticides can cause direct harm to humans and other non-pest animals as well. It is therefore important to properly use and dispose of pesticides in order to keep these harmful chemicals out of Hawaiʻi’s waterways.

3. Protect Soil Resources: Plant Cover Crops

Exposed soil can be easily washed away by rain and irrigation water into nearby waterbodies. Sediment clouds the waters and aquatic animals (including corals) can be smothered. Agricultural landowners can keep soil on their land by planting cover crops on fallow land, rangelands, and grazing lands. The University of Hawaiʻi (UH) Cooperative Extension website provides resources on cover crops. This practice is not only beneficial for human water consumption and the survival of aquatic species, but also preserves the integrity of landowners’ soil, reducing the need for soil amendments or even regrading.

4. Implement Agroforestry Techniques

In contrast with modern industrial agricultural practices such as monocropping and leaving land fallow after harvest, agroforestry techniques work with nature to reduce negative impacts on soil health and erosion, increase productivity, and capitalize on the ecosystem services that different species provide.

Here are some examples of agroforestry practices:

  • Alley Cropping – planting trees or shrubs in alternating rows with crops to serve as windbreaks and aid nutrient cycling
  • Forest Farming – growing trees, shrubs, and groundcover together to improve the productivity of a space and reduce weeding
  • Riparian Buffers – planting trees and other plants along streams to intercept fertilizers, pesticides, and sediments
  • Silvopasture – incorporating livestock grazing with tree and crop cultivation to reduce weeding costs, add nutrients back into the soil, and diversify production

Each technique has certain benefits and drawbacks, depending on the use case. Learn more about agroforestry techniques with this resource from the U.S. Department of Agriculture: Agroforestry.

Best Management Practices

  • Manage animal manures to minimize runoff to surface water
  • Use planned grazing systems in pastures and on rangeland
  • Use pesticides carefully and dispose of them properly. To learn where pesticides can be properly disposed of, visit the Hawaiʻi Department of Agriculture site.
  • Work with local conservation partners to understand local strategies
    • Soil and Water Conservation Districts

Resources

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