Data Analysis

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Data Analysis
The Data Analysis section is intended to encourage students to practice describing and interpreting patterns in spatial data.

This activity contains 5 questions.

The following pair of graphs shows accumulated precipitation (top) and stage (bottom) for an urban creek in Sacramento, California. Stage is a measure of height of the water surface above some arbitrary elevation. It is NOT the same as discharge, but it is a good replacement when discharge data is not available. Review these graphs and answer the following questions.

First, scrutinize the format and structure of the graphs. If the most recent data provided (on the right side if the graphs) is from February 27, 2004 at about 1pm, what time and date do the graphs begin? How long of a time span is this? What do the repeated numbers 6, 12, and 18 along the bottom of the graphs indicate?

To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.

To read and interpret the precipitation graph properly, you must understand that each upward "jump" in the line (reading from left to right) is a rainfall event. Unlike the stage graph, the precipitation doesn't rise and fall -- it only rises. This is because it is recording accumulated precipitation and NOT the rate of precipitation. With this in mind, what is the date, time, duration, and amount of the two biggest rainfall events on the graph?

To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.

Now, focus your attention on the stage graph. (The red line represents flood stage and the green line represents monitoring stage.) How does the stage respond to big rainfall events? How does it respond to small rainfall events? Is there much lag time between the precipitation event and increases in stage? How quickly does stage return to normal after the rainfall event?

To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.

This pattern of precipitation and stage (discharge) is utterly characteristic of an urban stream environment. Explain why.

To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.

Take a look at this data gathered about three months later. First, describe WHAT you see in the data, and second, try to explain it. It should seem somewhat strange, but you might be able to come up with some theories.

To create paragraphs in your essay response, type <p> at the beginning of the paragraph, and </p> at the end.

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