math in the news: issue 96

MATH IN THE NEWSIssue 96

The California Drought

THE CALIFORNIA DROUGHT The year 2013 was the driest year on record since 1894,

and conditions have only continued to worsen in 2014. This follows several years of dry winters in California, raising concerns about overall water trends.

THE CALIFORNIA DROUGHT Residents of California have had to restrict their water

usage as a way to conserve the limited amount of water available. People have been advised to limit watering plants and grass, and be mindful of water usage in daily tasks (brushing teeth, taking showers, and doing laundry). (SaveOurH20, www.saveourh2o.org)

http://www.saveourh2o.org/

THE CALIFORNIA DROUGHT

Californians have also suffered from record wildfires due to the extremely arid conditions. (The Atlantic)

http://www.theatlanticcities.com/jobs-and-economy/2014/03/no-relief-sight-drought-ravished-california/8696/


The effects of the drought reach throughout the United States, as we rely on California agriculture for almost half of the nation’s supply of fruits, vegetables, and nuts.


This map shows the severity of the drought throughout the state of California.(Source: United States Drought Monitor)

http://droughtmonitor.unl.edu/Home/StateDroughtMonitor.aspx?CA


THE CALIFORNIA DROUGHTThis table shows conditions throughout 2013. Conditions have been consistently dry, but the severity has been increasing. (Source, United States Drought Monitor)


THE CALIFORNIA DROUGHTWater is stored in reservoirs. Current water levels are shown in the map. The measurements are in acre-feet, a unit of volume equal to the volume of a sheet of water one acre in area and one foot in depth.

Source: California Department of Water Resources

http://cdec.water.ca.gov/cdecapp/resapp/getResGraphsMain.action




With this information, we can assess the differences between

current water levels and average water levels, and current water

levels and capacity.


Transfer information from the map to a chart.

Name of ReservoirCapacity

(acre-feet)Average percent

filledCurrent percent

filled

Trinity Lake 2,447,650 68% 53%

Lake Shasta 4,552,000 58% 46%

Lake Oroville 3,537,577 61% 46%

New Melones 2,400,000 69% 43%

Folsom Lake 975,000 67% 42%

San Luis 2,041,000 47% 42%

Don Pedro 2,030,000 73% 53%

Millerton Lake 520,500 46% 32%

Pyramid Lake 180,000 103% 94%

Castaic Lake 325,000 94% 84%

Exchequer 1,032,000 42% 23%

Pine Flat 1,000,000 39% 22%

Note how great the difference is between this

year and the average!


What is the average amount of acre-feet of water in each

reservoir at this time of year?


Name of ReservoirCapacity

(in acre-feet)Average percent

filledAverage acre-feet

filledTrinity Lake 2,447,650 68% 1,664,402Lake Shasta 4,552,000 58% 2,640,160

Lake Oroville 3,537,577 61% 2,157,921.97New Melones 2,400,000 69% 1,656,000Folsom Lake 975,000 67% 653,250

San Luis 2,041,000 47% 959,270Don Pedro 2,030,000 73% 1,481,900

Millerton Lake 520,500 46% 239,430Pyramid Lake 180,000 103% 185,400Castaic Lake 325,000 94% 305,500Exchequer 1,032,000 42% 433,440Pine Flat 1,000,000 39% 390,000

Ex: 1,000,000 x (0.39) = 390,000


How many acre-feet of water are currently in the reservoirs?


Name of Reservoir

Capacity (in acre-feet)

Average percent filled

Average acre-feet filled

Current percent filled

Current acre-feet filled

Trinity Lake 2,447,650 68% 1,664,402 53% 1,297,254.50Lake Shasta 4,552,000 58% 2,640,160 46% 2,640,160

Lake Oroville 3,537,577 61% 2,157,921.97 46% 2,157,921.97New Melones 2,400,000 69% 1,656,000 43% 1,032,000Folsom Lake 975,000 67% 653,250 42% 409,500

San Luis 2,041,000 47% 959,270 42% 857,220Don Pedro 2,030,000 73% 1,481,900 53% 1,075,900

Millerton Lake 520,500 46% 239,430 32% 166,560Pyramid Lake 180,000 103% 185,400 94% 173,900Castaic Lake 325,000 94% 305,500 84% 273,000Exchequer 1,032,000 42% 433,440 23% 237,360Pine Flat 1,000,000 39% 390,000 22% 220,000

1,000,000 x (0.22) = 220,000


How many fewer acre-feet of water are in each reservoir than expected (average)? Let’s look at Trinity Lake.

There are 367,147.50 fewer acre-feet of water than the average.


What percent of expected water levels is currently filled?

The water levels in the Trinity Lake reservoir are 77.9% what is expected at this time of year.


Continue exploring the changes in water levels by answering the following questions: How many fewer acre-feet of water are in the rest of the

reservoirs? What percent of the expected water levels in the reservoirs is

currently filled? How many more acre-feet of water, total, are expected at this

time of year compared with actual current acre-feet of water? Investigate how the water is allocated and the effects the

shortage in water resources has on the state of California and on the United States.

math in the news: issue 96

Education