September 19, 2017

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Healthy soil is the key to life; it’s absorbent, fruitful and durable. However, as the Southeastern Colorado landscape sees water less frequently, the inevitable arroyo formations are exacerbated by flash floods. With heavy rain, water flows over the impenetrable, hydrophobic soil and takes the path of least resistance.

On Chico Basin Ranch, rain flows through dried streambeds. The power of the high volumes of water is no match for the soil, and the vulnerable streambed channels continue to erode, forming a deep trench that prevents the formation of healthy soil on the stream bank and in the channel. Without healthy soil, vegetation cannot grow, and the dry, fruitless streambed carves a deep wasteland through the ranch.

In the past, the environmental science program at Colorado College had studied the landscape at Chico Basin Ranch utilizing drone technology. With the guidance of the ranchers at Chico Basin, we decided our resources would be most useful for studying an eroded streambed on the property and devising mitigation strategies.

We flew two drone missions, twenty minutes each, to acquire aerial imagery of the study site. Once back on campus, we were able to use our drone images in ArcGIS to see where along the streambed erosion was happening fastest.  With a solid grasp on how the streambed was affected by heavy but infrequent rainfall, we were able to model in ArcMap how the stream flow would change if a berm were built. Our analysis showed that it would take three six hundred-meter berms to completely change the water direction away from the streambed.

Sandbag structures installed in the creek to manage erosion.

Although this mitigation strategy would divert the water off the streambed, it is an inefficient use of resources and would be a major undertaking for the ranch.  Therefore, the research project concludes that a different solution should be studied and considered to prevent soil erosion.  In the future, it would be effective to model a detention basin that would fill with water and slow down the water flow into the streambed.  In addition, flying annual drone missions over the eroded streambed will be telling of how rapidly the erosion is moving upstream.

Overall, it was a pleasure to work on this research project at Chico Basin Ranch. I really enjoyed driving the dirt roads with my team and walking the dried streambed, taking transects at the nick points and flying a drone through the study site. It was an eye opening educational experience of a lifetime that has given me skills in erosion management that I would like to apply towards a future career.

By Madeline Lee

Colorado College ‘17

Environmental Science Major, Computer Science Minor

Photography by Madeline Jorden