Agriculture’s Impact on Stream Health
Land that has been converted to agriculture use can heavily impact the natural function of streams, if not taken care of correctly. Agricultural activities can result in significant changes to stream corridor’s structure and environmental functions that we all benefit from. Working too close to a stream corridor or changing the shape of the stream can lead to vegetative removal from streambanks, floodplains, and uplands. Removal of vegetation can often lead to increased flooding, soil erosion, runoff, and soil compaction. Soil compaction can also be caused by repetitive heavy traffic over a piece of land.
Changes to Stream Shape and Flow:
- Streams are often straightened or moved to “square-up” fields for more efficient production and reconstructed to a new profile
- Stream corridors are also often modified to enhance conditions for single purposes such as fish habitat, or to manage conditions such as localized streambank erosion
These disturbances can result in:
- Gully erosion
- Reduced water infiltration
- Increased upland surface runoff and transport of contaminants
- Increased streambank erosion
- Unstable stream channels
- Impaired habitat
- Increased water temperature, turbidity, and pH
Tillage and Soil Compaction:
Tillage and soil compaction interfere with soil’s capacity to partition and regulate the flow of water in the landscape, increase surface runoff, and decrease the water-holding capacity of soils.
Compaction of the soil are common in agricultural and construction areas due to the use of heavy equipment, continual traffic of equipment or livestock, and less vegetation to help maintain soil health.
Tillage also often aids in the development of a hard pan:
- A hard pan is the layer of soil below the surface soil to become extremely compacted, to the point it restricts root growth and water can’t move further into the ground
Disturbance of soil associated with agriculture generates runoff polluted with sediment. This can be caused by improper storage and application of animal waste from concentrated animal production facilities.
These facilities are then potential sources of chemical and bacterial contaminants to stream corridors. Additionally, pesticides and nutrients (mainly nitrogen, phosphorous, and potassium) applied during the growing season can leach into ground water or flow in surface water to stream corridors, either dissolved or adsorbed to soil particles. Dissolved contaminants in surface/ground water entering these areas become concentrated in the shallow ground water and the soils as water evaporates.
For information on how Headwaters SWCD helps prevent these issues, go to the Cost-Share Programs tab or About Us.