How Sediment, Snowmelt, and Stormwater Affect Your Water

Winter water management often focuses on ice, low temperatures, and the reduction of visible biological growth. Yet one of the most significant contributors to nutrient loading occurs during a period that receives far less attention: late winter runoff.

As ice melts and accumulated snow shifts into flowing water, nutrients that have been dormant become mobile again. This includes:

• Phosphorus carried from shorelines

• Fertilizer remnants stored in soil

• Decomposing organic material

• Sediment layers are temporarily trapped under ice

These nutrient pulses often occur before anyone sees green on the surface, making them hard to detect. During late winter, the landscape is quiet. Grasses, aquatic plants, and shoreline vegetation are not actively growing. Their root systems are not absorbing nutrients, and frozen soils restrict infiltration. This creates conditions in which water moves freely, carrying phosphorus and other nutrients downhill without any natural buffering. Even small snowmelt events can introduce meaningful nutrient loads into water bodies.

Many managers become aware of nutrient issues only once they are visible. However, nutrient loading usually occurs far earlier, weeks or months before environmental conditions favor growth. This makes late winter one of the most critical, yet least recognized, windows in lake and pond stewardship.

Planning Ahead: Staging and Prevention

Instead of reacting during peak conditions, managers can anticipate runoff cycles. This may include:

• Designing shoreline buffer zones

• Improving drainage or filtration at inflow points

• Conducting late-year sediment and nutrient testing

• Adding nutrient-binding strategies before peak runoff seasons

When planning is proactive, the system begins to spring closer to balance rather than recovery.