Water for Schools
Menu

Worksheet Grade 12 Social Studies & Civics

Relicensing Corryvale Dam: Flow, Power, and Fish

A grade 12 worksheet in which students price a fish-flow settlement at a fictional hydropower dam and weigh lost generation against regional visitor spending.

Objectives

  1. Students will convert an increase in river flow into the electricity and revenue a hydropower plant gives up.
  2. Students will total the annual cost of a license settlement and compare it with the regional spending it is expected to produce.
  3. Students will explain why the costs and the benefits of a license condition land on different parties.

Vocabulary

Key words: relicensing, minimum flow, cubic feet per second, megawatt-hour, settlement, water quality certification

Teacher overview

A hydropower license runs for decades, so the years when it comes up for renewal are the rare moments when a river's operating rules can change. Agencies, tribes, outfitters, and the license holder usually negotiate a settlement rather than litigate, and the currency of that negotiation is water: every additional cubic foot per second sent past the turbines is electricity the owner does not sell. This worksheet gives students the numbers behind one such settlement at the fictional Corryvale Dam and asks them to price the fish flow before judging it.

Relicensing Corryvale Dam: Flow, Power, and Fish — Grade 12 Social Studies & Civics
Name: ____________________________ Date: ______________

Student Worksheet

The fictional Tolworth Power Company owns Corryvale Dam on the Ashlon River. Its federal license is expiring, and the company has asked for a new 40-year license. The current license requires the dam to release at least 40 cubic feet per second, written cfs, to the river below. The state fish agency wants 120 cfs from June 1 through September 30, a season of 122 days, to keep the trout reach cool and wet. Before the federal license can be issued, the state must certify that the project will meet state water quality standards, which gives the fish agency real leverage.

Use these figures from the fictional settlement talks. Each cubic foot per second that passes through the turbines for one day produces 70 kilowatt-hours of electricity. The company sells power at $45 per megawatt-hour. A fish ladder would cost $1,400,000 to build, and the company would spread that cost over the 40-year license. Monitoring the fishery would cost $25,000 every year. A county study estimates that a stronger trout fishery and better summer paddling would bring in $310,000 a year in visitor spending.

  1. How many more cfs would the dam release under the agency's request than under its current license?
  2. Multiply your answer to item 1 by the 122-day season. How many cfs-days of extra flow is that?
  3. Each cfs-day through the turbines makes 70 kilowatt-hours. How many kilowatt-hours would the company give up each season?
  4. Convert your answer to item 3 into megawatt-hours by dividing by 1,000.
  5. At $45 per megawatt-hour, how much sales revenue does the company give up each year?
  6. The fish ladder costs $1,400,000 and is spread over the 40-year license. What is its cost per year?
  7. Add your answers to items 5 and 6 to the $25,000 yearly monitoring cost. What is the company's total yearly cost?
  8. The county expects $310,000 a year in visitor spending. Subtract your answer to item 7. What is the yearly difference?
  9. Your answers to items 7 and 8 do not describe the same people. Explain who pays the cost and who receives the visitor spending.
  10. The state must certify that the project meets state water quality standards. Explain why that requirement gives the fish agency leverage in the settlement talks.
  11. Suppose the company offers 90 cfs instead of 120 cfs for the same 122 days. Using the same 70 kilowatt-hours per cfs-day and $45 per megawatt-hour, how much sales revenue would it give up each year?
  12. Recommend a summer flow for the new license. Support your recommendation with two of the figures you calculated.

From Water for Schools (waterforschools.org). This material is in the public domain (CC0) and may be copied, edited, and shared freely.

Answer Key
  1. Answer: 80 cfs. The request of 120 cfs minus the current requirement of 40 cfs is 80 cfs of additional flow.
  2. Answer: 9,760 cfs-days. 80 cfs times 122 days equals 9,760 cfs-days.
  3. Answer: 683,200 kilowatt-hours. 9,760 cfs-days times 70 kilowatt-hours per cfs-day equals 683,200 kilowatt-hours.
  4. Answer: 683.2 megawatt-hours. 683,200 divided by 1,000 equals 683.2.
  5. Answer: $30,744 per year. 683.2 megawatt-hours times $45 equals $30,744 of forgone sales for the fictional company.
  6. Answer: $35,000 per year. $1,400,000 divided by 40 years equals $35,000 each year.
  7. Answer: $90,744 per year. $30,744 plus $35,000 plus $25,000 equals $90,744.
  8. Answer: $219,256 per year. $310,000 minus $90,744 equals $219,256 more in visitor spending than the settlement costs the company.
  9. Answer: The company pays every dollar in item 7 out of its own generation revenue. The visitor spending in item 8 goes to guides, outfitters, motels, restaurants, and the county tax base, and none of it returns to the company. The settlement moves value from one owner to many businesses, which is why the company bargains hard over each cfs.
  10. Answer: A federal license cannot be issued unless the state certifies the project will meet state water quality standards, so the state can attach conditions to that certification or withhold it. The fish agency therefore negotiates from a position where refusing to agree can stall the license entirely, rather than merely filing a comment the licensing agency may set aside.
  11. Answer: $19,215 per year. The extra flow would be 90 minus 40, or 50 cfs, and 50 times 122 days is 6,100 cfs-days. That is 6,100 times 70, or 427,000 kilowatt-hours, which is 427 megawatt-hours, and 427 times $45 equals $19,215.
  12. Answer: Answers vary; accept any recommendation supported by two computed figures. A student favoring 120 cfs can cite $310,000 in yearly visitor spending against a $90,744 yearly cost, a difference of $219,256. A student favoring 90 cfs can cite the drop in forgone sales from $30,744 to $19,215 and argue the fishery still gains most of the summer flow. A recommendation with no figures does not answer the item.

Differentiation

Support

Give students a labeled conversion ladder for the fictional Corryvale figures that runs from cfs to cfs-days to kilowatt-hours to megawatt-hours to dollars, with the first two rungs completed. Allow them to skip item 11 and spend that time on items 9, 10, and 12.

Extension

Ask students to redesign the settlement so that the company's yearly cost falls below $60,000 while the summer flow stays above 100 cfs, then explain what the fish agency would have to accept in exchange and whether it should.

ELL supports

Pre-teach "relicensing," "minimum flow," "settlement," and "certification" using a simple side view of a dam that labels the turbine path and the river channel below. Provide the frames "The company pays ___ because ___." and "The county gains ___ because ___." for items 9 and 12.

Extensions

Have students write the one-page summary the fictional Tolworth Power Company would file with the licensing agency, stating the flow it accepts, the cost it bears, and the public benefit it claims. Ask a second group to write the fish agency's response, then compare which figures each side chose to feature and which it left out.