Northfield Gears Up for More Business
From the Winter Spring 2001 Waterline, the quarterly newsletter of the Minnesota Department of Health Public Water Supply Unit, Waterline, Minnesota Department of Health
Spanning more than 100 years, the history of public water supply in Northfield, Minnesota, began in the mid-1890s with a well, a pumphouse with a steam-driven pump fueled by coal, and a rudimentary distribution network that initially delivered a daily average of about 127,000 gallons to the citys residents. Within a quarter-century, the volume of water pumped and distributed had doubled. Today, as the Northfield Water Division has entered its third different century of service, the utility produces over 725 million gallons of water per year (a daily average of nearly two million gallons) with more on the way as St. Olaf College is in the process of hooking up to the city supply.
The Water Division now has five wells, four of which are in use and are rotated on a daily basis. Each has a capacity of approximately 2-million gallons per day, enough to meet daily demand during much of the year, although its necessary for the utility to operate two wells simultaneously to meet peak needs during the summer.
Well 2 (adjacent to Well 1, which was capped in 1985 but could be returned to service in an emergency) draws from a combined aquifer. Like the abandoned Well 1, Well 2 is cased to a depth of 109 feet, at the level of the Prairie du Chien aquifer. It has a total depth of 400 feet and also draws from the deeper Jordan aquifer. Wells 3, 4, and 5 are cased to 318 feet, with total depths between 365 and 405 feet, and get their water from the Jordan aquifer.
Superintendent Doug Lien says they have to keep an eye on the nitrate levels of Well 2. With its shallower depth, the well produces levels of between 2.5 and 3.5 parts per million (ppm), well below the maximum contaminant level of 10 PPM but still high enough to cause concern. As long as the levels do not creep any higher, though, the utility will continue to use the well, which has a capacity of 1,300 gallons per minute (or 1.87 million gallons per day); Wells 3, 4, and 5 have a capacity of 1,400 to 1,450 gallons per minute (slightly more than 2 million gallons per day).
The utility feeds chlorine and fluoride at each of the wells. Polyphosphate has also been added for the last four years to sequester iron and manganese. Northfields raw water has an iron content of .2 parts per million and manganese levels of .11 PPM However, the addition of polyphosphate as well as nighttime flushing of hydrants in the spring and the fall has helped to clean up the water.
The original water system was installed near the end of the 19th century. Some improvements were made over the next 50 yearsmost notably the replacement of the original well, in response to concerns by the state health department, with the drilling of Well 1 in 1945 and Well 2 several years later. Water mains were also extended to supply new service areas. In 1950 service was cut from the original water department on Water Street and moved to its current location at 1101 College Street.
Despite the shift in location and other enhancements such as the new wells, no widespread modernization of the system took place until the early 1960s, when work began on a variety of projects, including construction of a pair of 1-million-gallon ground storage reservoirs on a wooded hill on the campus of St. Olaf College. Other work done at this time included an expansion to the pumphouse and the installation of chlorine equipment as well the modernization of electric motors and controls, and automatic pump and tank controls, which allowed for more than one pump to work at a time. In addition, 25,000 feet of water mains, ranging from 6 to 12 inches in diameter, were installed, creating a loop almost entirely around the city and allowing for greater expansion.
This expansion continued as a result of the citys continued growth, and the utility added wells in 1970 and 1978. Well 1 was taken out of service in 1985 but another well was put on line in November of 1997.
There was other major work during this time, including some massive infrastructure replacement in the mid-1990s that yielded an interesting find in the form of a section of cast-iron pipe that bore the date 1893. Operator Dean Huschle says the pipe was in remarkably fine condition although the joints and other parts of the infrastructure, such as valves and hydrants, showed considerably deterioration.
More recently the utility performed extensive maintenance on its ground storage tanks, sandblasting and painting the vessels inside and out in addition to enlarging the existing access holes and adding a new access hole to each.
This latest work has put the utility in good shape to take on a new customer, St. Olaf College. Last October the city and the college agreed to connect their systems. St. Olaf had found high levels of radium in its groundwater and decided to begin purchasing water from the city rather than install treatment to reduce radium levels. The connection will be made by 500 feet of 12-inch watermain that will tap into the citys line near the two ground storage tanks and bring the water into the St. Olaf pumphouse, which will become a booster station to bring the water to the colleges water tower. St. Olaf will retain its tower as well as its distribution system.
St. Olaf College has been using an average of 192,000 gallons per day during the school year and 114,000 gallons per day in the summer months. The Northfield Water Division should have no trouble meeting the increased needs, according to Huschle. The colleges peak demand will come during the months when the citys usage is typically lower.
The city has already been using two wells during the summer, and the demand during the non-summer months should normally be met with the use of just one well. Huschle also pointed out that a second well would automatically turn on, if needed.
For now, only one of the citys colleges is purchasing water from the city. However, there is always a possibility that a similar connection with Carleton, Northfields other college, could someday happen. Lien says that Carleton already has a hookup from the city for the purpose of fire protection and water supply backup. This water is unsoftened, and the college would be reluctant to use it unless absolutely necessary since it now softens the water it supplies to students.
However, another hookup recently went in from the city to the colleges power plant, enabling the college to soften the water before distributing it. If Carleton ever has a problem with its well or tower, it might consider doing what St. Olaf did and switching to the citys water.
Lien makes it clear that Carleton has not made any overtures regarding switching to city water but that the hookups now exist should the college ever make such a decision.
Meeting the water needs of their users is a top priority for the Northfield Water Division, and communication is also a key part of that mission. Huschle has worked to produce an annual water quality report since the mid-1980s, more than a decade before such reports became mandatory under the federal Consumer Confidence Report Rule. The Northfield report includes a description of the system and its work over the previous year as well as information on the utilitys long history.
Two years ago, Northfield produced a video on the water division and has shown it on local-access cable stations. Huschle says public response to their communication efforts has been positive.
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