All the freezing and thawing this March has created little cracks in the ground. Seeing these cracks along my running and biking route made me wonder about erosion, the wearing away of the earth by wind, water, and ice.
I first learned about erosion as a youngster. In science class, I viewed pictures of the Grand Canyon, which was carved over time by the Colorado River, and the Badlands of the Dakotas, created from erosion deposits. My class also watched movies about how different rivers of the world formed and flowed to create the surrounding land shapes. This natural process fascinated me because of the beauty in the formations.
No So Beautiful Personal Experience
When I was a teenager, I learned that erosion can also be ugly. A neighboring farm was sold to a new owner who wanted to do some excavation on the property. Huge bulldozers and graders were brought in to level the earth. All summer long, these machines went around and around moving trees, dirt, rock, and anything else in their path.
The project dragged on through the fall and ceased when winter arrived. The spring rains that year were very heavy. Water washed over the loose dirt, creating little rivers. The rivers continued to grow in depth and width, some four to five feet in depth and one to two feet
wide. All the dirt washed down through the valley into the creek. Pipes that had been installed to help the creek flow became filled with silt, the dirt that had been transported by the water.
The creek water could not flow through the pipes, so the water backed up over the creek bed to form a pond. With each rain, the water grew higher, flooding tree roots and trunks along the creek. The water grew very stagnant, allowing algae to form. We called the DEP in to investigate because all the backed up water was ruining trees on our property and creating a health hazard and all the erosion ruts were wreaking havoc on wildlife passing through the property.
We later learned the owner’s actions were illegal because no permits had been issued for the excavation. The property ended up being sold again to people who restored the land as much as possible and corrected the pipe issue so the creek water could again flow.
Erosion at Work
Though man’s actions contributed to my personal erosion experience, the erosion process itself is a natural occurrence. Water falling in the form of rain runs into creeks, streams, rivers and then on to the ocean. The flowing of the water creates friction on the soil surface, causing the surface to wear down and deteriorate.
Erosion can also be created by wind. The force of the wind picks up tiny particles of soil and carries them to other locations. Ice can also cause erosion by forcing itself into the earth. Tiny cracks open up in the soil. As the ice expands, so do the cracks. When the ice melts, the cracks remain unless filled in by nature or man.
Nature prevents erosion from happening in the form of trees, shrubs, grass, and other plants. The roots form a network to keep soil in place and prevent water from moving the soil elsewhere. Trees and taller plants also help break the wind’s force when blowing, which prevents soil particles from being lifted up from the surface.
Humans can prevent erosion by planting grass, plants, bushes and trees; installing drains and pipes to keep water runoff contained; and using fences or barriers when excavating or digging up large sections of land.
In the case of the neighboring farm, a company trucked in soil to fill the ruts and then hydroseeded the entire property. The grass grew quickly and was not cut by a mower until the root system was well-established. Though the neighboring farm does not have the virgin look of yesteryear, it does have a beauty of its own and a rather unique story to tell.
Resources and Links
Grand Canyon- http://www.nps.gov/grca/index.htm