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Environmental Studies Department |
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Analysis of Water Consumption at Macalester CollegeBy Jennifer Tahtinen and Katy Thompson May 2001
As part of the senior seminar for environmental studies at Macalester College in Saint Paul, Minnesota, water consumption was analyzed on campus. The analysis is three-fold. Information was obtained on the quantity of water used at Macalester, how much it costs annually, and what the most water-intensive activities and buildings are. A discussion of conservation efforts already in place and suggestions for future reduction of water use are included. Information was obtained through the City of Saint Paul and personal interviews with the Chief Engineer at Macalester College, Dave Bergstrom. Since the 1970’s, there have been efforts at conserving water. More efficient technology was developed, such as plumbing fixtures and low flow shower heads. Improvements on existing technologies continue to be made today. Federal laws have also improved in regards to water conservation. For instance, law now mandates that all toilets sold and installed in the United States are low flow, saving as much as four gallons of water per flush. Campaigns on the part of environmental and water quality groups have led to an increased public awareness of conservation. Every child in the United States now knows that they should turn off the water while they are brushing their teeth! How Water Gets to Macalester Saint Paul Regional Water Services is the utility that provides water for the City of Saint Paul and the surrounding suburbs. It is a self-supporting entity that obtains its revenue through the sale of water and payments for services provided to other organizations. No taxes are used to maintain the utility, but it is dictated by state law. Due to its location, Saint Paul does not have a shortage of water sources. There are ample lakes, and obviously it is located along the Mississippi River. Seventy to eighty percent of Saint Paul’s water comes from the Mississippi River. The rest is obtained from wells in the Vadnais Lake area. See Figure 1 for a map diagram of Saint Paul’s water supply system. A chain of lakes north of Centerville Pumping station are used as a reserve for times of high demand. Sixty-five to ninety percent of the water intake is located in Fridley, where it is pumped to Charles Lake of the Impounding Reservoir System. The reservoir system has a watershed of approximately twenty-eight miles and a water supply of 3.6 billion gallons. Eventually, the water is pumped to Vadnais Lake. All of the water for Saint Paul passes through this lake. Saint Paul has very high quality water, partially due to the fact that it passes through reservoirs before being treated. The water from the Mississippi River is of variable quality, but as it passes through the lakes it goes through natural processes that help to filter and purify it. From Vadnais Lake, the water goes through two 90-inch conduits to the water treatment plant, which is located four miles to the south. The maximum rate of water to the plant is 200 million gallons per day. Gravity is used to help convey the water instead of pumps, thus saving enormous amounts of electricity. Once the water reaches the plant, it goes through a series of chemical treatments and processes so that it is drinkable by federal standards. In Saint Paul and the surrounding suburbs, there are 1,100 miles of water mains to distribute the water from the treatment plant to the city. The storage capacity of the mains is up to 136.2 million gallons, which is approximately two and a half times the daily demand. There are high service and low service regions of Saint Paul. Macalester College is located in a high service region, which means that a lot of the water must be pumped to the campus due to the topography of the city. Reservoirs in Highland Village, Roseville, and Hillcrest store water for the region of Saint Paul that Macalester is located in. The average daily water use by the area served by the Saint Paul Regional Water Service is 50 million gallons. Annually, Saint Paul and surrounding areas use 18.3 billion gallons of water. On average, an individual uses 100 gallons of water every day. Depending on the flow rate of a showerhead, a five-minute shower uses between five and twenty-five gallons of water. Why Conserve Water? Conserving water is good for the environment and it makes economic sense. Economically, using less water means a lower reading on a meter, translating into saved dollars. In the short term, it may cost money to retrofit fixtures so they have a lower rate of flow, but retrofitting will eventually pay for itself, often in a short amount of time. Less water flowing through the Saint Paul Regional Water Services system also means less energy spent in pumping and treating the water. A lot of electricity would be saved if pumps were not used as heavily as they are now. Also, maintenance costs would be less as the system is used less intensively. When water is used by the City of Saint Paul, it enters the sewer system, eventually going back into the Mississippi River. As the water is recycled over and over again by different cities, its quality becomes poorer. Water is full of organisms and microbes that are beneficial and important to many biological processes. When water is treated these organisms are killed, and when the water re-enters the Mississippi River, a slew of chemicals are added to the watershed of the river. Watersheds are incredibly important ecological areas, and pollution of them can be especially dangerous because it can spread rapidly through the water over a very large area. The watershed of the Mississippi River, for example, is a very large portion of the central United States, covering multiple states. Macalester's Water Budget Macalester College allots approximately $45,000 from the Physical Plant's budget each year for water, or approximately 0.01% of the school's annual budget. After speaking with Dave Bergstrom, the chief engineer of the Physical Plant, we found the specific amounts paid to the City of Saint Paul for the water Macalester College consumed. We found that these figures varied quite a bit from FY 1997 to 2000 (Figure 2). After asking Bergstrom, he told us that the discrepancies in the numbers are not due to increased consumption of water, but due to when the bills were actually paid. In actuality, he said that water consumption at Macalester has remained fairly constant over the last several years. In fact, this year there may actually be an increase in water consumption simply because of the new addition of the new campus center. This discrepancy between years was just the first of many problems we encountered in our research of water consumption at Macalester. Next we found out that no one's entirely sure how much water is used annually. There is no meter tracking the water consumption of the campus as a whole, instead the campus is divided up into metering blocks (Figure 3), and each block is charged separately by the City of Saint Paul. This makes it very difficult to track changes in consumption of the campus, or even the consumption of the metered blocks, as the individual records have been misplaced or lost, so specific numbers are unknown. Despite not knowing the specifics of which building use the most water, the Physical Plant is looking for ways to decrease the water consumption on campus. Speaking with Dave Bergstrom, he told us that there were about four activities that consume the most water, and only three of these were controllable. These four activities are: the use of showers, toilets and sinks, cooling towers for air conditioning, sprinkling and the cooking and science facilities. The only controllable activity is the use of showers, toilets and sinks in the buildings on campus. All new buildings on campus must comply with new federal regulations about water conservation, including the use of 1.6-gallon toilets instead of the older 5-6 gallon versions. The new campus center, George Draper Dayton Hall, and Olin-Rice use these new toilets. Also, Dave Bergstrom is currently looking at bids to retrofit Doty, Bigelow, 30 Mac and the gym with new flushometers, sinks and showers that conserve water. Flushometers are the devices in toilets that regulate how much water is used with each flush. When flushometers get old, more water can be used with each flush, getting to the point where approximately seven to eight gallons can be used per flush. The new sinks and showers conserve water by using less volume. This current bid could save Macalester $5,134 a year and 308,000-gallons a year (Figure 3). The cost of the retrofitting is $10,591, but with these annual savings, the return on investment will only take 2.05 years. This is an example of what the school is willing to do to conserve water. As Dave Bergstrom put it, Macalester is "all for saving as much energy and water as possible" provided it makes economic sense. Concerns We interviewed several Macalester students to see what their concerns were regarding water conservation at Macalester. There was one major concern to the student body, and that was the amount of water used to water the lawns. This is especially problematic to students when the automatic sprinklers are on while it is raining. Dave Bergstrom addressed these concerns with us. He said it rarely happens that the sprinklers come on while it is raining because they are connected to an air sensor, which measures the humidity in the air. If it is raining, the sensor should override the system and keep the sprinklers off. However, sometimes the sensor becomes broken and the sprinklers will come on automatically even if it is raining. Bergstrom said that in this case, someone usually calls the Physical Plant to let them know the sprinklers are on, if they don't notice it first. The other major concern regarding sprinkling is the seemingly excessive use of water with the grounds crew. Again, Bergstrom addressed this concern, saying that there is a somewhat distorted view of the use of water by the grounds crew. He said that the heaviest watering of the lawns comes in September and October because the Athletic Department demands quality fields for football, soccer and other sporting events. Also, in May, there is an increased use of water on campus in order to make the lawns look good for commencement. While the grounds crew does use quite a bit of water in May, September and October, during the rest of the year there is dramatically less water used on the lawns. Problems at Macalester While no one outright will say that they are against water conservation, there are many problems with student behavior that prevent water from being conserved. The first problem is with the new, federally mandated 1.6-gallon toilets. Because there is less water in the toilet bowl, there is less pressure available to flush. Oftentimes, one flush is not enough and the toilet is flushed again, increasing the amount of water used up to 3.2-gallons. Sometimes even, in the lesser-quality toilets, another flush may be needed. The other problem with student behavior is in the dorms. Next to the science and cooking facilities, the dorms consume the most water on campus. To conserve water, the Physical Plant has replaced the high-flow showerheads with water saving showerheads. While this may seem like there is no problem, water-saving showerheads use a lesser volume of water than the high-flow ones. In order to make up for the lack of water flowing, they increase the pressure at which the water comes out of the shower head, and in some cases, the pressure causes the water to actually be painful. In those cases, students have vandalized the showers by removing the showerheads until the high-flow showerheads were replaced. Conclusion Macalester College as a whole seems fairly oblivious to the amount of water that is used on campus. While the Physical Plant sincerely wants to conserve water, there are not many additional ways of conservation that can be implemented. If we lived in an area where water was scarcer, water conservation may be of more importance to the school. But as it is, water consumption lacks the publicity needed to make conservation measures stick. Following are some suggestions to cut down on the amount of water used at Macalester College.
Figure 1: A diagram of the Utility's water supply system. The majority of the city's water is pumped from the Mississippi River to Charles Lake. After going through the reservoirs of the Impounding Reservoir Lake System, the water reaches Vadnais Lake. It is then pumped to the water treatment plant, where it is treated and then distributed throughout St. Paul and surrounding suburbs. Figure 2: Figure 3: Figure 4: Savings due to the retrofit of Doty Hall, Bigelow Hall, 30 Mac, and the gym.
Figure 5: Water consumption before and after the proposed retrofit.
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