Each spring and with practically every major rainfall, we have become accustomed to hearing of problems that occur with the region's sanitary sewer systems. Although much of the controversy has been focused on the city of Duluth, over the past several years, the city of Cloquet has been working closely with the Minnesota Pollution Control Agency (MPCA) and the Western Lake Superior Sanitary District (WLSSD) to upgrade its sanitary sewer collection and treatment system. The major focus of these improvements has been to reduce and eliminate Inflow and Infiltration (I&I).
Inflow and Infiltration (I&I) are sources of clear water, either rain or ground water that enter the sanitary sewer system. The major effect of inflow and infiltration is a significant increase in wastewater flows during the spring snowmelt and shortly after rain storms in the summer. This increase has lead to basement flooding, overflows of the sewer system and the discharge of untreated sewage into the St. Louis River and Lake Superior.
Although the city of Cloquet does not experience routine overflows of its sanitary sewer system, according to Cloquet Director of Public Works Jim Prusak, I&I is still an issue with Cloquet and every city that sends its wastewater to the WLSSD for treatment in Duluth. We all contribute to the problem and, as a result, each community has been required to annually develop an I&I Reduction Program and to report on the status of its efforts.
Over the past 20 years, much of Cloquet's efforts have been directed towards rebuilding and upgrading older portions of its collection system. Since 1985 the city has reconstructed approximately 46,400 feet of old sewer lines and leaky manholes at a cost of $1.8 million. Prusak concedes there is still more work to be done to the city's system, but at the same time their I&I Reduction Program must include the required inspection of every building in town in an effort to identify and eliminate other clear water sources. These inspections will include things such as roof drains, down spouts, footing drain tile and sump pump systems, which are improperly connected to the sanitary sewer system.
Improperly installed footing drain tile and sump pump systems are a major target of the city's inspection program. To keep a building's basement dry, drain tile is often installed around the outside perimeter of a building's foundation to collect and keep water from entering. In all cases, this is clear groundwater or rainwater runoff and does not need to be treated as sewage. In fact, the current state plumbing code and most local ordinances actually prohibit the discharge of this water to the sanitary sewer.
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These types of drain tile systems must be piped to a sump pit inside the basement. A sump pump is then installed in the pit to pump collected groundwater to the outside and away from the building. In some cases, these pits have been tied directly to the building's sanitary sewer line and flow into the city system. In other cases, property owners have installed sump pumps, only to discharge their water to a laundry tub or floor drain. All sump pumps must be piped directly to the outside of the building. They cannot be run to floor drains, laundry tubs or to any sanitary sewer connection.
To date, approximately 1,000 buildings have been inspected in Cloquet and 60 percent of them have been found to be in compliance or not contributing to the city's I&I problem. Within the last two weeks, letters were sent to 60 homes, mostly in the Sunnyside area, requesting the owners to contact the city to arrange follow-up inspections. According to Prusak, not all of these homes are in non-compliance but previous inspection records indicted something that needed a closer look. The Sunnyside area was selected for the first round of inspections because sewer flow monitoring has identified this part of town as a significant contributor to the city's I&I problem.
During the first snow melt that took place on March 13, flows at the Dunlap Island pump station jumped from an average of 110,000 gallons per day to 230,000 gallons per day. This station collects all of the wastewater from the Sunnyside area and then pumps it to the south side of the St. Louis River, where it then continues to Duluth. If the snow melt had been combined with a good rainfall, Prusak indicated flows at this pump station would have easily been three to four times higher.
In addition to the environmental concerns associated with sewer overflows, I&I results in additional treatment and pumping costs for all customers. It also reduces the available capacity of the sewer system to convey and treat wastewater properly. Prusak is quick to point out that this is a statewide problem that is getting more attention from the Minnesota Pollution Control Agency through increased rules and regulations. The agency is now refusing to issue sewer extension permits to cities that are not actively reducing I&I and enforcing the regulations.
Obviously, such a situation can have a negative impact on our community as we try to grow and diversify our local economy. But improperly installed sump pumps, or drain tile systems will also have a direct impact on individual owners. According to Prusak, if a non-compliant system is identified and it is determined that it is contributing to I&I, by city ordinance the owner could be charged an additional sewer fee that ranges between $15 and $50 per month. Cloquet has yet to begin charging such fees, but within the next month the Cloquet City Council will be considering an updated utility ordinance that includes such a fee in the event owners ignore or fail to correct non-compliant systems.
According to Prusak, it is not the city's intention to threaten fines, but to initiate a process to make people aware of the problem and to continue with the city's ongoing efforts to reduce I&I. Illegal or improperly installed roof drains, drain tile and sump pump systems are, in most cases, a matter of people just not knowing the regulations. Years ago there were no such regulations. Persons who have further questions or would like additional information on the city's I&I Reduction Program may call the city engineer's office by calling 879-6758. If you would like to schedule an inspection of your building, you may also do so by calling the same number.
This article was contributed by Jim Prusak, Cloquet Public Works director. Contact him at 879-6758 or at jprusak@ci.cloquet.mn.us .
