What is the additional setback required for winter manure application near agricultural drainage systems?

The additional setback required for winter manure application near agricultural drainage systems is important for protecting water quality and preventing nutrient runoff. The correct answer highlights the need for a specific distance—100 feet from surface flow. This distance helps ensure that any potential runoff from manure applications does not directly enter surface waters, which can lead to nutrient enrichment and water quality issues, such as algal blooms.

Maintaining a 100-foot setback helps filter out nutrients and sediment before they reach open water bodies, thereby minimizing environmental impacts. This practice is based on best management practices that prioritize the protection of water resources during winter months when the risk of nutrient runoff is higher due to frozen or saturated soils.

The focus on surface flow is critical, as nutrient-rich runoff can have immediate and harmful effects on downstream ecosystems, making this requirement essential for sustainable agricultural practices.