Why is stream gradient important?
The gradient, or steepness, of a streambed drives many important processes, such as erosion, sediment movement, and the speed of water flow. Water and sediment move more rapidly through streams with a steep gradient, while streams that are more gradual in slope may have slow moving water that allows sediment to settle to the bottom.
Artificial changes to a stream gradient can create problems for sediment transport. Artificially steep channels can speed water flow and cause erosion. Artificially flat channels may result in slow moving water and excessive sediment deposits, which can contribute to flooding. Understanding how the gradient of a stream will impact flow and sediment transport can help managers develop a stream management plan.
How do we measure stream gradient?
An assessment of stream gradient is included in the overall assessment of the physical structure of a stream. Stream gradient can be assessed through the construction of a longitudinal profile, which is a diagram that captures the changes in elevation along the length of a stream.