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Olin Rice 249
1600 Grand Avenue
St. Paul, MN 55105
651-696-6274
Comments & questions to:
esson@macalester.edu
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Water Audit
By Karen Lucatelli
May 2002
The purpose of the 2002 water audit is to follow up on the findings from 2001 and track any progress made. I interviewed Dave Bergstrom, the Chief Engineer of the Physical Plant at Macalester College. He said that little had changed since the last interview in 2001. He confirmed that the biggest water-using activities are bathroom use of showers, toilets and sinks; air conditioning cooling towers; grounds; food service; and science laboratory usage.
Macalester took action towards reducing water consumption by retrofitting Doty, Bigelow, 30 Mac and the gym with new flushometers, which regulate the volume of water used per flush, as well as sinks and showers with a lower volume flow/minute than older shower and sink heads.
Last year, the audit predicted that the retrofitting would reduce water consumption by 308,000 gallons per year, which would translate into a savings of $5,134 per year. Since the initial cost of the retrofit is $10,591, they predicted that the return on investment will pay off in 2.05 years.
The buildings were retrofitted in June of 2001, and Dave Bergstrom reported that it was too early to calculate the savings. Comparison of years is complicated by the fact that the meter was broken for a few months and there are unexplainable variations for three of the months.
There was not a significant increase or decrease in the water use for all of the buildings that were retrofitted. There was a large variation in water usage per month. The average water expenditure per month from June-February 2000-2001 was $2331, and decreased from June-February 2001-2002 to $1981. However, the opposite trend occurred in the gym/pool. The average monthly water expenditure rose from $843, June-February 2000-2001, to $1061 in 2001-2002 after the retrofit for the same periods of months. Figures for Doty and 30 Mac were not available, since they are billed on a separate grid.
Since the pool is included in the figure for the gym/pool, I asked Dave Bergstrom how much pool water usage fluctuated. He said that the only reason they drain the pool is when they need to physically repair the walls or floor. Otherwise, the pool is filled to replace evaporated water, which is higher in dried months and would not have varied between the same months between 2000-2001 and 2001-2002.
Water is a resource that Macalester pays to consumer per unit volume. Reduced water usage is not only environmentally responsible, but it translates into direct savings for the college. The retrofitting was a solid beginning towards reducing water consumption, although it is too early to notice solid trends, and other variations in water use as well as inaccurate meter readings make comparison difficult. At this point, the numbers still vary considerably.
Retrofitting does not include any incentive for changing water consumption patterns. A water-reduction campaign, especially geared towards students living in the dorms, would save water and money at Macalester.
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