A flow is a rapid movement of earthen material down a slope, resulting in a landslide. These occur when the force of gravity causes a portion of soil or rock to extend laterally down a slight slope, which in turn causes rock fragments to fracture.įlows are exactly what they sound like. Lateral Spreads are very subtle as well, as they often occur on very gentle slopes. An indicator that this could be happening is “slump.” This process can often happen very slowly – too slow to even perceive with your eyes. Slides occur when the force of gravity pulls a portion of soil or rock “slides” down a slope as a whole unit. Eventually, the pull of gravity will cause the bedrock to “topple over” in segments, similar to dominoes falling on top of one another. Topples occur when a slope causes an entire body of bedrock to be tilted downslope. This occurs at the Indian Mound Reserve as Massie Creek erodes away at the bedrock on either side of the gorge, creating overhangs that eventually fail. Mass wasting is a broad term that can be categorized into several different types.įalls occur when rocks and other earth materials fall through the air due to the removal of their supporting material. It can be triggered by an earthquake, rainfall, volcanic eruption, or simply the collapse of supporting materials under physical stress over time. Mass wasting is a geomorphic process in which rock, soil, or any material of the like is pulled downslope by the force of gravity. Nonetheless, Massie Creek has still managed to form these features subtly along its path.Ĭan you spot at least one point bar or cut bank as you hike along Massie Creek? Because their courses are surrounded by rock, they cannot meander as freely as they may want to.
However, in mountainous areas or gorges like the one we see at the Indian Mound Reserve, streams are a little more restrained. These areas tend to have soft soil that streams can move through. Point bars and cut banks are most easily observed in environments that allow streams to meander freely, such as prairies and plains. Additionally, the small sediments that are carried by the water are not being driven downstream but rather are being dropped, which causes a buildup of deposited material over time. Meanwhile, there is much less force hitting the inside of the curve. The small sediments carried by the stream contribute to this action as well. As water barrels down a stream and hits one of these curves, it erodes or ‘cuts’ into the rock or earthen material on the outside of the curve. Once a stream starts to meander, it’s curves become more and more pronounced. ‘The channel morphology was characterized by alternating riffle, run, and pool segments that averaged 10-15 m in length.’ ‘They added more than 20 riffle weirs, 15 post vanes, and 80,000 willows to slow water down, protect streambanks, increase habitat and raise the water table. This natural event is described by the stream’s sinuosity. Notice how the water tends to meander in an S-shape rather than just straight down the plane. Have you ever thought about how streams of water tend to take a certain shape? To see what I’m talking about, pour some water down a sloped surface, such as a driveway.
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