Colorado River Homework

This assignment will require that you access a spreadsheet (GEOL150CORiverHW.xls) and a google Earth file (Colorado River.kml) both of which are available on the resources folder on our Sakai site. If you do not have google Earth on the computer that you will  be using to complete this assignment, you can download it for free and use it on any computer with a connection to the internet. I assume that you all have access to excel- let me know if this is not the case (Open Office Calc works fine as well). You should turn in this sheet and a document (word or word equivalent) with your written responses to 2-7 and graphs for 2,3,5,6, and 7. Your responses do not have to be long or detailed as long as they effectively demonstrate that you are able to make (reasonable) conclusions from the data that you are given.

The spreadsheet contains hydrographic data for eight stream gauges along the Colorado River that were operating throughout 2013. The raw data is made available to the public by the Unites States Geologic Survey and is available in 15-minute intervals; I have taken the raw data, dealt with  missing portions, and reduced the resolution of the data by averaging the discharge to hourly, daily, and monthly intervals (there are three tabs named hourly, daily, and monthly…). The other tab contains a table with information about the locations of the stream gauges and other important landmarks along the river. The google Earth file will give you a geospatial context for the data and will be necessary for completion of #8. This assignment is due at the beginning of class on Wednesday, February 26th. I will be hosting help sessions for any interested students on the evenings of Monday and Tuesday after break (the 24th and 25th) and, of course, I will be available to assist via email or in person (including over the break).

1. Use the highest resolution data set to find the average discharge for each stream gauge. Provide this in the table in the “Table” tab and on the table on the back of this sheet in cubic feet per second (cfs) and millions of acre feet per year with three significant digits for each.

2. Plot an elevation profile for the Colorado River using the data provided in the “Table” tab. Describe the profile.

3. Plot the total volume of water for each stream gauge as a function of the contributing drainage area for the river at each stream gauge location. Describe what you see and note any evidence for large-scale diversion projects.

4. Find the difference in annual volume of water between each of the stream gauges. Match these numbers up with the large-scale diversion projects in #3 and include your numbers in the table on the back of this sheet.

5. Plot data from all eight stream gauges resolved at monthly intervals (average). Describe the similarities and differences between the discharge patterns of the Colorado River at the eight stream gauges. What does the difference between discharge patterns up and downstream of the Hoover Dam suggest about the importance of the storage capacity available at Lake Mead?

6. Plot the hourly resolved discharge for Lee’s Ferry and the Grand Canyon from June 30 to August 3. What is going on here? What is the average flow velocity for the reach in between these stream gauges? Give your answer in miles per hour with one significant digit.

7. Plot the daily resolved discharge for Lee’s Ferry for a few weeks. What does the pattern suggest about when we consume electricity?

8. Use the ruler tool in google Earth to find how far the Colorado River travels in Mexico before completely drying up for imagery collected on 4/9/2013 (probably the default) and on 8/18/2007. Use the diversion at the Morales Dam as the border crossing and give your answer to the nearest mile. How does this compare to complete distance to the Gulf of California. Express your answers as a percent of the total distance inside of Mexico with two significant digits.