Measuring Erosion Rates - Cascabel Watershed

This post also deals about my trip to Cascabel Watershed on 7th and 8th of November 2009. As mentioned in my earlier post, Cascabel Watersheds are located in the Malpai Borderlands in the eastern part of the Coronado National Forest on western edge of the Animas Valley along the United States-Mexico border. The Malpai Borderlands are found within, and are representative of, the larger Southwestern Borderlands region. Cascabel Watersheds (total area 451 acres) include twelve different watersheds ranging from about 20 to almost 60 acres in size. Our study covered 7 of the total 12 watersheds within Cascabel Watersheds.

Photo-1: One of the 7 watersheds

In this post, I want to describe how I helped my group in estimating erosion rates from the watershed. The watersheds have varying slope so it was obvious that erosion takes place in varying rates.

Photo-2: Slopes at varying degree

In each watershed erosion was measured in every 3 points along the transects. In each of these points, there was a pin within the ground.

Photo-3: Erosion/Deposition Pin

We used a metal detector to detect the point.

Photo-4: Metal Detector

Then the soil level above or below the pin head was measured and was compared with similar measurement done in past years. If it showed that soil level was below the past measurements, it showed erosion and if soil was found above the last measurement, it detects deposition.

The method is simple and easy to implement in the field. Though there can be errors like in detecting the pin as it can be displaced in the field or the measurement of soil level might not be quite accurate. But there is no doubt that this method gives a relative measure of erosion and deposition going on in the watershed that contributes in making management implications for best management practices.