Featured Blog: Water and Where Does Roseville Get It?

During my recent trip to Japan, I picked up a booklet in our hotel lobby listing attractions for visitors in the Tokyo area.  Flipping through pages of ancient temples and world class museums, I stopped on one page that caught my eye: the regional water treatment plant. 

Tours of the facility, I learned, are available to the public during cherry blossom season in the spring, and during the "Week of the Water System" in the summer.

Alas, my visit didn't correspond with the Week of the Water System, but the fact that they have such a celebration of their water infrastructure is telling.  The metropolis has 12 million people living shoulder-to-shoulder, and the infrastructure that makes life possible is too important for citizens not to be aware of.¹

I realized that I know very little about where our water comes from.  After a quick web search I found that Roseville's water is supplied by St. Paul Regional Water Services (SPRWS), although Roseville maintains its water system and sends out the bills to its customers. 

The majority of our municipal water supply comes from the Mississippi River.²  A pumping station in Fridley can pump up to 84 million gallons a day through a chain of lakes including Pleasant, Sucker, and Vadnais.  SPRWS has two backup water supply systems, the Rice Creek chain of lakes and groundwater from four deep wells in the Prairie Du Chien-Jordan aquifer.

All of this water is then piped to the SPRWS Water Treatment Plant in Maplewood where it is treated and tested to ensure compliance with all state and federal standards.  The city of Roseville conducts additional monthly tests.

A summary of the monitoring data shows that potential contaminants are all well below the federal limits.³  However, this same report notes that emerging contaminants such as endocrine disruptors that enter rivers through the wastewater stream (as partially-metabolized pharmaceuticals, antibacterial soap, caffeine, and insect repellants, for example) are not regulated and are only partially removed during the treatment process. 

The U.S. Geological Survey, Minnesota Pollution Control Agency, and Minnesota Department of Health have measured these compounds in water sources around the state (including water leaving the SPRWS treatment plant) at around 3 parts per billion.  Effects on humans from chronic low-level exposure are unknown, but are thought to be minimal.  However, these chemicals are known to be affecting fish and other aquatic wildlife and understanding these effects and ways to prevent this pollution is a major research challenge.

A more noticeable issue has been occasional complaints about the taste and odor of municipal water,^4,5 which result from algae growing in these lakes during the summer and early fall.  Although the safety of the water supply was never in question, SPRWS installed activated carbon filters in 2007 that have cut down on the number of complaints dramatically. 

SPRWS has also restored wetlands around Vadnais Lake to soak up nutrients and uses aeration systems in Vadnais and Pleasant lakes to control phosphorus levels that cause these algae blooms.⁶ 

There are numerous reasons to drink tap water instead of bottled water.  The price, for starters.  Additionally, tap water is at least as safe as bottled water.  Municipal water is subjected to stricter oversight, and unlike for bottled water, test results are publicly available. 

The environmental costs are certainly far greater with bottled water, when you consider the energy costs associated with shipping water across the country and the trash produced by disposable bottles.⁷   

But the answer to the question "Where does my water come from?" is not a simple one, and illustrates the challenges involved in protecting a metropolitan water supply. 

Our drinking water comes from rain and snow that fall across the entire Upper Mississippi River Basin--so pollution in central Minnesota ultimately affects us here in the Twin Cities. 

But our own actions affect our water quality as well, because runoff from the northern suburbs enters our water supply through the chain of lakes.  Even the aquifer 400 feet below ground is connected to surface water, and is susceptible to pollution. 

Because much of the infrastructure of the water system is hidden below ground or behind fences, it is easy to think of water as magically appearing when we turn on the faucet. 

However, as an increasing number of people in the Twin Cities rely on this "life support system", we would be wise to better understand how it works.  Perhaps we should follow Tokyo's example and have a "Week of the Water System" in the Twin Cities to help raise awareness.

Notes

¹The aquatic science conference I was attending in Japan was on the shore of Lake Biwa, and ancient lake famous for endemic fish species and freshwater pearls, and it also serves as the water supply to 15 million people in the nearby cities of Kyoto, Osaka, and Kobe.  Surrounding the lake are steep mountains, and these watersheds have been largely protected over the centuries because they were considered to be sacred.  It turns out to be wise--and cost effective--to protect water sources, as has been shown by New York City.

² Data from http://www.health.state.mn.us/divs/eh/water/swp/swa/swainfo/surfwaterFile/1620026.pdf.  Note: this document is from 2001 so doesn't reflect updates to the water system in the last decade.

³ http://www.cityofroseville.com/DocumentCenter/View/10715

⁴ http://www.stpaul.gov/faq.aspx?TID=21

⁵ http://mn-stpaul.civicplus.com/DocumentCenter/Home/View/4639

⁶ Phosphorus binds to sediment in oxygenated lakes, but when lakes become anoxic, this nutrient gets released from sediment, thus fueling more algae growth.

⁷ Even if plastic water bottles are recycled, this process takes energy--and water.  Macalester College has eliminated bottled water on its campus for these reasons (http://www.macalester.edu/sustainability/bottledwater.html).