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In the Fargo-Moorhead region, three types of mass wasting impact slopes bordering the Red River and its tributaries. Slump can result in major and rapid slope retreat, especially in regions of river cutbanks. Creep and earthflow, generally induce lesser amounts of damage, although these processes can occur on any slope.
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The region of Trollwood Park in north Fargo provides excellent examples of the three types of mass wasting processes. Here, in this 1982 photo, fence posts are tilted downslope under the influence of creep. Creep, earthflow, and other processes would soon destroy the asphalt path, as well. Note the position of the affected slope on outside of a Red River meander.
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Creep is the imperceptibly slow, downslope movement of soil and earth materials. Rates of movement are often only a few centimeters per year, but the inevitability of creep can severely impact shallowly-placed structures. Where emplaced upon slopes, sidewalks, walls, and fenceposts can be displaced or destroyed by creep.
| Tensional stresses induced by creep are causing this asphalt path in Trollwood Park to fracture. Soil flow is toward a deep gully to the left of the path. (1994 photo).
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This fence near Trollwood Park is being pulled apart under the influences of creep. (2000 photo).
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Trees, having root systems near the surface, are often affected by creep. As trees succomb to creep, they continue to grow phototropically toward the Sun, giving the trunks of the trees a curved shape.
| Shallowly-rooted trees can be tilted downslope by creep. However, the trees will respond phototropically by trying reestablish grown upward. The result is a trunk curved upward. These trees are near the Red River in Fargo's Edgewood Golf Course. (2000 photo).
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Earthflow is the downslope movement (flow) of a mass of earth materials, typically resulting in a lobe-shaped landform. Development of earthflows in our region tends to be coupled with extremely high soil moisture conditions.
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A lobate earthflow is visible at the left-center of this photograph. The Trollwood Park barn (razed in 1997) is visible in the background. Note the fenceposts succombing to creep. (1985 photo).
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| An earthflow affects a slope near the junction of Trollwood Drive and North Broadway. (2000 photo).
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NORTH DAKOTA STATE UNIVERSITY
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