1122 Lab 4 - (Questions)

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Name: Jaden Badillo-Ryan TA: Lab 4 - Groundwater GEOL 1122 Before answering the questions for each section, make sure you have watched the video(s). After you have completed this worksheet, save it and upload it to the assignment folder for Lab 4 in iCollege. Please use your own words to answer the questions, and include as much detail as possible . Lab Objectives At the end of this lab, students should be able to:  Explain what groundwater is (and isn’t)  Understand the magnitude/scale of groundwater as a global hydrologic reservoir  Explain the basics of aquifers and name associated terminology  Explain the difference between porosity and permeability  Explain and name basic relationships between groundwater and surface water (i.e., gaining versus losing stream)  Understand land subsidence and its causes (recharge versus withdrawal)  Explain how to determine direction of groundwater flow and what controls flow velocity Part 1: Introduction To answer these questions, first watch the “Lab 4, Part 1: Introduction” video on iCollege. Please answer the questions in your own words. 1) H ypothesize a factor that you think will affect the rate (i.e., speed) by which precipitation infiltrates to recharge groundwater and explain how this factor will affect it (e.g. will it make recharge faster or slower) ( 4 pts) One factor that would affect the rate by which participation infiltrates to recharge the groundwater would be weather patterns. This factor would affect the groundwater recharge speed because if there is not a lot of precipitation or if there is a drought the groundwater recharge speed will slow. 2) Explain whether or not you would expect an aquifer to be composed of clay. (4 pts) I would not expect an aquifer to be composed of clay because clay does not have good permeability. 3) Please use the internet to research whether or not karst terrain is found in the Atlanta area. Also include an explanation as to why or why not this terrain is present. ( Important : please include links to all websites used for this question) (4 pts)

There wasn’t much information on Karst terrain in Georgia but from what I was able to find there is some. I believe it makes since for there to be Karst terrain in Georgia due to its diverse landscape. https://link.springer.com/article/10.1007/s13146-019-00525-z 4) You are a geoscientist measuring discharge at different points along a stream. You measure discharge as 3 m/s at one point in a stream, and then measure discharge as 4 m/s at a point 10 meters downstream with no tributaries between these points. Explain your reasoning as to whether this is evidence of a gaining stream or losing stream. (2 pts) This is evidence of a gaining stream because it increases in discharge as you move down the stream if it is not by much Part 2: Porosity and Permeability Watch the linked YouTube video “Porosity and Permeability” in its entirety to answer these questions in your own words . 5) According to the video, what percentage of total US freshwater is supplied by groundwater, and what are the two main uses given for this water? (4 pts) It is 25%. The two main uses are agriculture and domestic. 6) Define the term “infiltration,” and explain its role in the context of the hydrologic cycle. Is infiltration considered a reservoir or a flux? (Hint: review the PowerPoint from the surface water lab) (4 pts) Infiltration is the movement of water from the surface into the ground. Infiltration happens after precipitation in the water cycle which then allows for plants to grow. Infiltration is considered a flux. 7) As explained in the video, a common misconception is that groundwater is water found in underground rivers or lakes (this is in fact relatively uncommon). Explain where groundwater is actually commonly found. (4 pts) Groundwater is commonly found stored between grains of gravel and sand. 8) Define porosity in your own words. (2 pts) Prosperity is the amount of void space in rocks 9) If gravel is placed in a 400 ml (milliliter) container, filling it to the top, and 160 ml of water is added to completely fill the container, what is the porosity of the material? Give your answer in both decimal and percent forms and show/explain your work. (4 pts)

160/440= 0.4 0r 40% 10) What is the common range in porosity for unconsolidated (i.e., not lithified) gravels and sands near earth’s surface? What is the percentage of shallow groundwater systems in the US that contain sand and gravel deposits? (2 pts) Common range is 15-40%. About 80% is the percentage of shallow groundwater systems in the US that contain sand and gravel deposits. 11) Define permeability in your own words. Then, explain how permeability is different from porosity as precisely as possible. What example did the video give of a material with high porosity but low permeability? (4 pts) Permeability is a rock or sediments ability for water to flow through it. Permeability is different from porosity because porosity is the ability to hold said liquid that flows through the rocks or sediment. Part 3: What is an Aquifer? Watch the linked YouTube video “What is an Aquifer?” in its entirety to answer these questions in your own words. 12) Please define the terms “aquifer” and “confining unit” in your own words, using as much detail as possible. (4 pts) An aquifer is a large body of permeable rock that hold ground water. A confining unit does not have permeability and stops the movement of water. 13) How does water from precipitation enter into a confined aquifer? How is this different from the recharge process in an unconfined aquifer? Additionally, list and explain all the processes given in the video by which groundwater levels in an aquifer can be increased or decreased. (4 pts) Water from precipitation enters where the materials pop out of the surface, while in an unconfined aquifer water can move down freely. Groundwater levels can be increased if the water is refilled more often then it is consumed and decrease if it is consumed faster than it is refiled. 14) Name and briefly discuss all of the different types of typical US aquifer geologies discussed in the video (e.g., sand & gravel, etc.). In doing so, compare and contrast their characteristics in terms of relative porosity and permeability, as well as where in the US these are generally found. (4 pts) Sandstone: Common in western states. Low porosity and permeability Sand and gravel: Common in North Dakota and Ohio. High porosity and permeability Igneous and Metamorphic: Common in Washington. No porosity or permeability Limestone: Common in Florida. High porosity and permeability

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Part 4: Where is the Water Table? Watch the “Where is the Water Table?” video in its entirety to answer these questions in your own words . 15) What type of rocks contain the groundwater measured in this video? Why is this not typical, and what is the reason these rocks are able contain groundwater? (Hint: review the previous video to recall why these types of rocks are not commonly associated with groundwater) (4 pts) It would be Metamorphic rocks because they have low porosity and cant contain groundwater 16) Name the instrument used to measure the monitoring wells in this video, and give a brief description of how it works. (2 pts) The measuring instrument used was a water level meter. A water level meter is a measuring tape that is connected to a probe and beeps when it touches the surface of the water. 17) Two monitoring wells are located close together. You record the elevation (in meters above sea level) of the top of the PVC pipe for each well. Then, you measure the distance from the top of the PVC pipe to the water level surface at each well in meters. Results are recorded below: Well Name Elevation of top of PVC (m) Distance to Water Level Surface (m) Well A 150 2.1 Well B 152 3.5 Use these results to calculate the elevation of groundwater above sea level for both wells in meters (with work and units shown). Then, state whether groundwater is moving from Well A to Well B or from Well B to Well A. Please fully explain your work and reasoning. (4 pts) Well A: 150m/ 2.1m = 71.42 m Well B: 152m/3.5m = 43.43m It is moving from Well A to Well B.

1122 Lab 4 - (Questions)

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