## Based on the map and your interpretation of the data, what is the direction of groundwater flow at this site for April 6, 2020?

Now that you have used a ‘dataset’ that you were given, and interpreted that data through visual representation, you are ready to take the next step and come up with your own. Bear in mind, these are very small datasets, as often in science, or any field like business or marketing, you will more likely have large sets of data – hundreds or thousands of rows or columns on a spreadsheet.

In science, you will often need to change variables in an experiment, so this is a thought exercise to better understand how changes to one element in an experiment may affect others. Think for a moment that we are not working with water, but in a laboratory using the scientific method to test an hypothesis. You have already made an observation (“that is an unusual event!”), then asked a question (“why did that happen?”), came up with an hypothesis (“that happened because this item interacted with this item.”), and now you are ready to test your hypothesis to see if it is correct. Say that the test showed it is not correct, so you go back and revise your hypothesis, or maybe changing the items involved to see if it was actually something else that caused the effect. Maybe you were testing which combination of gunpowder and metals created a green color in a firework, and your first combination that you used created a blue color. So you change the variable until you get green, then you make sure it can be reproduced and works the same each time.

This is an example of why you may need to modify elements in an experiment. In this lab exercise, it isn’t quite the same, but the principle is the same: you are creating your own experiment, as if you had gone out in the field and collected these measurements yourself. You will then change the numbers and doing it again, to see how the results (flow direction on your map) change.

Lab #3 – Instructions

For Lab #3, you will be using the same site, but you are given an Excel spreadsheet with the formulas to calculate the elevation for your OWN water depths. You will then plot them on another blank site plan, and interpret that data. Then, you will change the depths that you came up with, or simply switch the numbers to different wells, and interpret the data on a second blank site plan. Once you have done that, you will answer the questions on the next page. The instructions for doing this lab exercise are the same as for Lab #2, but you will be doing them twice with different datasets.

1. Plot the elevations at each well. Remember, the elevations represent feet above sea level, so higher numbers mean a higher point, and lower numbers are lower points.
2. Draw lines (they may not be straight, sometimes they will be curved) to represent the major contours of elevation. Do not use round numbers for this, as in nature, the depths are almost never even. Feel free to use larger numbers, although in Miami, elevations rarely vary by more than 0.05-feet across a site this small.
3. Draw a line with an arrow showing which direction you have determined (inferred, in other words) groundwater is flowing.
4. Now, change your depth-to-water numbers by different amounts (such as add 0.10 to one of the wells, 0.13 to another, maybe 0.06 to a third well, etc), and re-plot the new elevations on your second site plan.
5. Draw your lines of elevation, and draw a new line with an arrow showing the changed direction of groundwater flow.

Lab #3 – Questions

• Based on the map and your interpretation of the data, what is the direction of groundwater flow at this site for April 6, 2020? .
• Is the direction of groundwater flow similar to the direction on any of the elevation maps from Lab #2? .
• How did the flow direction change for April 6, 2020 when you changed the numbers for the depth-to-water readings?
• If you were to notice these different values, and did not know that you had changed them, what would you think could explain the two different sets of data? (there is no right answer here, it is all about trying to conceptualize)