SCI 207 Week 3 Lab Report

Week 3 Lab

SCI 207

Our Dependence Upon the Environment

Week 3 Lab

Introduction

During this lab we were exploring how groundwater and surface water interact. This is important because we need to be aware of what we are doing with the water we are using on a daily basis and how that might affect our clean water supply. “As the Nation’s concerns over water resources and the environment increase, the importance of considering ground water and surface water as a single resource has become increasingly evident” ( Winter, et al., 2011, para. 1). By realizing our groundwater and surface water are linked by one continuous loop via the Hydrological cycle, the importance of keeping our water clean is easy to see. If we pollute our surface water and let it reach our groundwater without being properly cleaned we will contaminate large portions of underground water extremely quickly.

The main purpose of this lab was to see how groundwater and surface water interacted with each other.

Activity 1. I think that removing water from the well will only slightly change the water level in the reservoir. A reservoir would have a mostly clay bottom which would make water transfer happen very slowly to the aquifer. I think removing water from the well will only slightly lower the level in the reservoir.

Activity 2. Yes I believe some of the polluted water will enter the groundwater supply from the reservoir. It will be a slow leak into the groundwater supply but it will happen. The water soaked bottom of the reservoir will allow some water to enter the ground water supply.

Activity 3. I think that both wells will have some pollutants in the water supply. Even though the well on top of a hill is above an impermeable layer the well draws water from below that layer. I think that the fertilizer will be present in both wells.

Materials and Methods

Activity 1. I used a plastic container, clay bar, plastic tubes, sand, gravel, 3 straws, tap water, a permanent marker, a pipet, and a foam cup for this experiment. I made a model reservoir and aquifer split by the clay bar, the aquifer was filled with the sand and gravel and 2 plastic tubes were placed to act as wells in the aquifer. I filled the plastic container with water till it was approximately 2 cm above the clay bar, the top of the water represented the water table. I placed a straw in well 1 and placed my thumb over the other end to trap the water inside the straw. I then removed the straw and marked where the water level was. I then used the pipet to remove all the water from the well and stuck the straw back in an measeured the water depth as before and made another mark on the straw, this was to simulate a period of pumping from the well. I then waited 2 minutes and stuck the straw in a third time and made another mark. This experiment demonstrated the effects pumping water from the well has on the water table. I then repeated for the second well.

Activity 2. I was able to reuse my reservoir and aquifer model for this test as well. I drained the model and added a piece of aquarium tubing taped to the side of the reservoir making sure it was not touching the bottom. Then I added clean water to the reservoir until the water level was approximately 2 cm above the clay bar. I took some Kool-Aid mix and mixed it in a cup of water to act as a pollutant. I extracted the “pollutant with a 10ml syringe, connected it to the aquarium tubing in the reservoir and pumped it in. I observed what happened and waited 1 minute, then used a straw as before to check the water in one of the wells for the pollutant. I checked every minute for 5 minutes.

Activity 3. For this experiment I needed to reconfigure my model. I reused the plastic tray aquarium tubing and gravel. On the opposite side of the tray I added another piece of the aquarium tubing at the same depth. I then added sand on the bottom of the tray that was higher on one side then the other. I placed gravel on top of the sand while maintaining the grade I had set with the sand. I molded the clay into a small flat sheet and placed that on the high side of the tray and covered that with sand. At the low end of the tray I dug a small pond in the sand and gravel and filled it with water. I then sprinkled Kool-Aid mix on the area between the clay and the pond. I used the cup from earlier with holes in bottom and simulated rain over the area. I observed what with the Kool-Aid powder and saw it quickly seep into the pond. I waited 30 seconds and used the 10 ml syringe to remove the water from the pond. I then used the syringe to remove the water from the uphill well by connecting it to the aquarium tubing.

Results

Discussion

Activity 1 I accepted my hypotheses because I feel like the experiment showed the reservoir level changed only a little bit but the water in the aquifer showed a diminished volume. Activity 2 I accepted as well because the pollutants seeped thru the reservoir and could be seen in the well. Activity 3 same thing, I feel like the experiment validated my hypothesis.

I have learned the importance of making sure not to contaminate our ground water. If our surface water is contaminated it does not take long at all for those pollutants to make their way to our ground water. I also learned how wide spread a pollutant in one area can quickly spread to another area via the ground water. People need to make sure to do all they can to keep pollutants suck as oil, chemicals, excess fertilizer and other harmful substances out of our water.

The biggest challenge for me was the size of the plastic container that came with the lab kit. I wish it would have been a little longer; I had a hard time trying to get everything laid out exactly the way I wanted it to be for activity 3.

A scientist could use this understanding of the relationship between surface and ground water to help pinpoint the source of a pollutant.

References

Winter, T. Harvey, O. Alley, W. (2013, January 11). Ground Water And Surface Water A Single Resource. USGS. Retrieved from https://pubs.usgs.gov/circ/circ1139/