A John Adams Middle School 7th-grade Algebra class, led by teacher Ms. Parisa Jung, took on the challenge of solving real-world applications about water usage in Los Angeles. The questions, posed by local non-profits — The Electric Lodge and LA River Expeditions — came from ongoing community discussions and dilemmas about revitalizing the Los Angeles River.
“I liked the idea of my students tackling real-life problems,†said Ms. Jung.
“No matter how young they are, I hope their answers will inform citizens and
contribute to new solutions by the people who make decisions about water usage
in L.A.â€
The first question was: The Los Angeles River is the reason why Los Angeles was settled where it is today. It used to be a source of fresh local water, but now we spend a lot of energy and money bringing water from hundreds of miles away.
On a normal sunny day, how many gallons of water do we dump into the ocean through the L.A. River? Provide the answer in total gallons, and also in
Olympic-sized swimming pools. Then calculate the loss of water for one year (same units of measurement).
Several students did research, crunched numbers and came up with answers to the extra-credit problems. The city engineering department provided an estimated flow rate of 320 cfs (cubic feet per second), which converts to 207 MGD (million gallons per day) — or roughly 75 billion gallons per year. With Santa Monica College’s big pool containing 660,000 gallons, then the total annual water loss is the equivalent of 114,477 Olympic-sized swimming pools.
The second question was: When it rains in L.A., we know that we essentially
throw away tremendous amounts of clean, free water. But how much? This last year (with measurements ending July 1, 2010), we had an average annual amount of rainfall: approximately 15 inches. How many gallons of water is that? With that amount of water, how many times could you fill up the Rose Bowl? And in an especially rainy year, like 2004-05, when we got more than 30 inches/year, how much water did we discard into the ocean (same units)?
Zaha Wolfe, a12-year-old in the class, explained his answer: “We calculated that 1 inch of rain over 1 acre equals 27,154 gallons, and since there are 318,912 acres in Los Angeles, that’s about 8.7 billion gallons for every inch of rain. An average year of rain will then produce approximately 130 billion gallons. We found out on a website that the Rose Bowl has a volume of 84,375,000 gallons. So… each year we could fill up the Rose Bowl 1,541 times (or 3,081 times/year with an especially large annual rainfall)! That’s really crazy and stupid, just watering the ocean! And, like, that’s not bad enough, then we drain lakes and rivers from other parts of the state?! I knew adults did weird stuff, but this just confirms my theory!â€
Joel Shapiro, founder and artistic director of the solar-powered Electric Lodge, in nearby Venice, California, responded to the class’s results: “The figures they uncovered are mind-boggling, even for people like myself who already think about these issues.”
For more information on the project and how other schools can participate:
www.electriclodge.org and www.lariverexpeditions.org
