GeoDESLA day 2 – Chucking things into rivers and calling it science!

By Olivia, Hanna, and Way

After a delicious breakfast we went to rock creek and took our time to observe the water and questioned ourselves why the creek is the way it is and how the creek is affected. We found out that there are different ways that a river is effected from the amount of stability the river has to the increasing amount of sediment the river carries. we measure the pH, (how acidic or basic the water is) the hardness, (how much the water has eroded and reacted with the rocks) and the Nitrate and Nitrite (how much humans affect the water and its nutrients).

The river can change depending on how much velocity it has and the amount of water that is traveling in the river. During our time at rock creek we were tasked with finding the Discharge of the creek by finding the volume and velocity of the water. However finding the width of the creek proved to be a problem. We couldn’t walk to the other side of the river because of safety hazards. So we brainstormed an idea of wrapping the rock with the measuring tape and throwing the rock to the other side of the creek. Some teams were better at this than others. We had to get the length, width, and the velocity. Each team picked a starting and end point to time their marshmallow, finding the velocity. This measurement then became our lengthy. The width was an estimation or some teams decided on tying a rock to a measuring tape and throwing it to the other side of the creek. This proved to need multiple attempts. After this we packed up and headed to our next site for lunch.

The 2nd site we visited was following Rock Creek, the same as the previous site, upriver. This site was in the town of Red Lodge so immediately we noticed some major differences from our first site. The rocks within the creek that had been moved down through time were bigger than downstream now becoming definite boulders. The boulders along the sides were man placed to help prevent erosion along the main road. The town has also built a wall along the creek for this same reason. This directly changes how the creek looks and behaves.

Rock Creek in Red Lodge

We noticed there was more white water meaning it was rather shallow compared to the last site. After lunch we split up into groups and measured the PH, NO3+NO2, along with the hardness of the water. Our assounding results were that of nearly no change besides the general landscape. Unfortunately we could not throw rocks across this area to measure the width or the depth of the creek so we resorted to guesstimating. We found that the discharge was also rather close to site 1. After we had done our experiments we refilled on water and headed out to our next area.

After a quick break at a gas station, we drove to the East Terrace of the Rock Creek, which is an area of flat sediment deposited by glaciers approximately twelve thousand, or more, years ago. Here we sketched the gorgeous view of the West Terrace, rivers, mountains, and the town of Red Lodge.

Next, we traveled over to the West Terrace to learn about groundwater wells. Some wells are drilled into the terrace ranging from ten to thirty feet deep. However, other wells are drilled over one hundred feet into bedrock, despite gathering less water than the shallower wells on the terrace. These bedrock wells are more reliable for cleaner drinking water since they are not as susceptible to contamination from human activity (fertilization) as the wells drilled in the terrace.

Later, when we returned to YBRA we attempted to predict the annual hydrographs (graph of the changes in the amount of water present throughout the year) of the streams and the wells. We learned that in both the wells and streams the amount of water is the lowest during the winter (November to January) and steeply increases in the spring and continues to increase during the summer months, until August, when it begins to decrease. In fact, the rate of increase during the spring is steeper than the rate of decrease during late-summer, which is interpreted to be due to the rapid melting of ice and snow in the mountains during spring. The hydrology of this are is very interesting and we enjoyed learning about the morphology of the river.

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