Groundwater Lab Spring 2022 Announcements: • Check canvas: withdraw deadline is April 15 (next Friday) • I will check in with your grader (Sammy) to make sure that grading is mostly up-to-date by then so you can see what your grade is • Today’s lab: use PowerPoint or Google Sheets or print out the PDF version • I will go over parts 1+2, then you will work on those in groups for ~30 minutes • I’ll bring us back together to go over parts 3+4 Groundwater vs. Surface Water 1. Surface water is water on the earth’s surface, like lakes, reservoirs, rivers, streams, oceans, etc… 2. Groundwater is water in the pore spaces of sediments and rocks below the surface Image from: Groundwater Diagram. Department of Environment & Conservation, Government of Newfoundland & Labrador (2016) Groundwater 1. The water table is the level where all the pore spaces are saturated, or filled, with water 2. Like surface water, groundwater is moving or flowing (but very slowly)! 3. Like surface water, groundwater flows from high to low elevation! 4. In the same way that we can create a contour map of the land’s surface topography, we can create a contour map of the water table! (part 3) Image from: Groundwater Diagram. Department of Environment & Conservation, Government of Newfoundland & Labrador (2016) Monitoring Groundwater with Wells Part 1 • Groundwater levels in wells in Denver • Demo • Incorrect link on slide 4 of lab: please use https://groundwaterwatch.usgs.gov/default.asp (I will send this powerpoint on canvas so that you all have the correct link) Part 2 • Porosity and Permeability • Watch 2 videos • Compare the porosity of different materials (gravel, sand) • Compare the permeability of different materials (gravel, sand, clay) • ~20-30 minutes for parts 1+2 Part 3: Intro to Groundwater Contouring GEOL 121: Physical Geology Lab Contouring a water table with groundwater well data What’s the direction of flow? Image from: Study.com https://study.com/academy/lesson/predicting-themovement-of-groundwater-the-behavior-of-wells.html Contouring a water table with groundwater well data What’s the direction of flow? *Note: Any streams and rivers on a map will be flowing in the same direction that the groundwater is flowing! Image from: Study.com https://study.com/academy/lesson/predicting-themovement-of-groundwater-the-behavior-of-wells.html Contouring Rules/Common Mistakes • Contour lines should NOT cross NO • Contour lines should NOT merge or split NO Steps to Contour (Slide 14 in lab) 1. Select a contour interval • For the map you’re doing use a contour interval of 50 feet (i.e., the 1200, 1150, 1100, 1050, 1000 ft contours). 2. Locate the Highest or Lowest groundwater elevation – start contouring there 3. Using the elevations at wells as a guide, draw lines representing a single groundwater elevation 4. Remember, groundwater flow will be perpendicular to the contour lines Contouring Practice Image from: https://study.com/academy/lesson/pre dicting-the-movement-of-groundwaterthe-behavior-of-wells.html 350 ft 340 ft 330 ft 320 ft • • • • 10-foot contour intervals Highest contour: 350 ft Lowest contour: 250 ft I will do a few contours as a demo Contouring and Streams *Reminder: Any streams and rivers on a map will be flowing in the same direction that the groundwater is flowing! Image from: https://throughthesandglass.typepad.com/through_the_sandglass/arid-lands/ Drawing the water table on a cross section Image from: Colombia.edu Now it’s your turn! Part 4 • You will write a brief statement about what declining water levels mean for Douglas County and how you would mitigate the problem • The rest of the lab time: • Work in your groups to answer parts 3+4 • I will check in on groups periodically to see how you’re doing • Type in chat if you need extra help References for pictures • Image 1: Groundwater Diagram. Department of Environment & Conservation, Government of Newfoundland & Labrador (2016) • Image 2: study.com: https://study.com/academy/lesson/predicting-the-movement-of-groundwater-the-behavior-of-wells.html • Image 3: study.com: https://study.com/academy/lesson/predicting-the-movement-of-groundwater-the-behavior-of-wells.html • Image 4: through the sand glass: https://throughthesandglass.typepad.com/through_the_sandglass/arid-lands/ • Image 5: Colombia.edu: http://www.columbia.edu/~vjd1/groundwater_basics.htm
