Streams naturally tend toward a state of equilibrium between erosion and deposition of sediments. As streams meander through their floodplains, the outside of the stream cuts into the bank eroding it away, while the inside of the stream deposits sediments to create point bars further down the course.
The natural process of erosion and deposition can be disrupted by human activities such as dams, dredging, agriculture, development, or logging. Construction projects or logging in the upper reaches of a watershed may worsen erosion or sediment deposition on someone else’s property further downstream. If people straighten, narrow, or move stream channels without taking into consideration their natural energy, erosion and sediment deposition rates can increase, resulting in the loss of valuable agricultural land, damage to roads or structures, destruction of productive wetlands, and addition of sediments and nutrients to our waterways that can degrade surface water quality and biodiversity.
If sediment is abundant, it covers the gravel and cobble stream bottoms needed for spawning areas. Habitats for aquatic insects that serve as food for many fish are also destroyed by sedimentation. Suspended sediment particles in the water lead to a decrease in light availability. The best way to prevent sediment from reaching lakes, streams, and wetlands is through careful project planning and implementing stringent erosion and sediment control methods during construction.
The Vermont Agency of Natural Resources has created information on the fundamentals of river systems, why rivers need floodplains, channel evolution, erosion hazards, assessing stream stability, mapping hazards, and protecting river corridors. Because channel alteration often produces counterintuitive results, any riverside project should have qualified engineers that understand river dynamics.
Links are provided below to written materials and technical experts. The Connecticut River Joint Commissions has also created a very useful guide to River Dynamics and Erosion designed to help property owners, town planners, road crews, and decision-makers understand how rivers work. Included is a stream assessment guide to locate factors causing or resisting erosion.
To learn more information about bank erosion and sedimentation, please visit these websites:
Vermont Agency of Natural Resources River Management Program
River Corridor Protection & Management Fact Sheet
Defining River Corridors Fact Sheet
Vermont Department of Forests, Parks, and Recreation - Acceptable management practices for maintaining water quality on logging jobs in Vermont.
Vermont Agency of Agriculture - Agricultural Resource Management and Environmental Stewardship.
Joint Commissions Guide to River Dynamics & Erosion
In This Section
Acid Mine Drainage
Bank Erosion & Sediment
Basin Planning
Fisheries
Floodplain Management
Good Road Maintenance
Grants
Invasive Species
Mercury
Non-Point Source Pollution
Organizations
Permits
Riparian Buffer Zones
Wastewater Treatment
Water Quality Studies
Water Supply Protection
Wetlands