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Sea Grant Helps Efforts to Reduce Storm Runoff

RSPT logo

The City of Duluth has a problem. A 100-million-gallon-sized problem. Because the city is built on a hard-surfaced hill that slopes into Lake Superior, water runs off it like the proverbial duck's back. Heavy rains or warm spring weather often result in a quick snowmelt and send more water rushing through the sewer system than it can handle. Consequences include sewage overflows into basements, city streets, and into Lake Superior and the St. Louis River.

Sea Grant is part of a team working to protect and enhance the region's water resources through stormwater pollution prevention by providing coordinated educational programs and technical assistance. The Regional Stormwater Protection Team (RSPT) is composed of 16 governments and groups, including the cities of Superior, Duluth, Proctor and Hermantown.

Especially in Duluth, due to its unique topography and soil types, the RSPT has its work cut out. An average Duluth home can produce as much as 1,400 gallons of water runoff in a typical rainstorm. In late March of this spring, total overflows of 214,000 gallons were reported from two pumping stations in eastern Duluth. It brought the flow to two-and-a-half times the average, with more than 112 million gallons coming into the local sanitary district water treatment plant per day; the Western Lake Superior Sanitary District (WLSSD) plant is designed to handle an average of 43 million gallons.

Throwing Money Down the Sewer

To encourage proper stormwater drainage, the city has been working with WLSSD to implement an inflow/infiltration grant program to disconnect footing drains and install sump pumps or gravity discharges in 500 homes yearly. During the seven years of the program, over 2,000 buildings were disconnected. Most of the drainage problems originate in the eastern end of the city, which is only 3-1/2 miles away from the drinking water intake for the city, and from the intake of the U.S. Environmental Protection Agency's Mid-Continent Ecology Laboratory, where sensitive water and chemical experiments are conducted. WLSSD hired a consulting firm to assess the inflow/infiltration program's effectiveness in this part of the city. The firm found that there's been a "significant reduction" in stormwater flow to the sewers and that the program is cost-effective.

The city is also seeking $4.95 million in state bonding to help fund construction of an underground storage tube to hold excess sewage and help eliminate overflows in the eastern end. The overflow storage basin would hold about 800,000 gallons of sewage until high flows subside and the sewage can be eased back into the system. If the state bonding money is approved, the city would match it with $7.45 million; still far short of the money needed to totally solve the problem.

To upgrade the aging sewer system, WLSSD might spend $8.6 million this year - half of the amount would go towards backup power generators because several huge sewage spills in 2003 involved electrical or mechanical malfunctions. The rest of the money would go towards replacing sewer lines, manholes, and a pump station. The district's residential and business customers are the ones who will foot the bill, paying about 74 cents more per month for sewer charges.

The $8.6 million is part of a 10-year, $52 million plan to replace and upgrade major pipes and pump stations, and $19 million to upgrade the WLSSD treatment facility. WLSSD and the city have sent these plans to the EPA and hope the agency will approve of the concepts and timelines involved to eliminate sewage overflows.

RSPT and Duluth Streams Battle Runoff with Information

This spring, the RSPT began a public education campaign with a brochure and local radio/television ads sporting a logo designed by UMD student Eric Lichtenberg. The group hopes to raise community awareness about how people's actions (particularly those of homeowners) can impact the water quality of streams and Lake Superior.

The city and Minnesota Sea Grant have also worked jointly over the past two years to produce a stormwater information Web site (www.duluthstreams.org). The Duluth streams site profiles each of Duluth's 42 streams that drain its steep slope into Lake Superior. Electronic sensors in four of the streams continuously monitor water flow, temperature, salt content and turbidity, which are broadcast on the Web site. The site also serves as a repository for maps, reports, community action activities, and other freshwater information that were scattered and difficult to access. The data are interpreted graphically so that they’re easy to use. Planned improvements will make the site even more comprehensive and convenient.

For more information about RSPT, order the stormwater brochure (item WQ 1) from our online order form or call the RSPT at (218) 529-3281.

By Marie Zhuikov
June 2004

Return to June 2004 Seiche

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