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Water: Nonpoint Source Success Stories

Minnesota: Lake Shaokatan Restoration Project — Improving Water Quality Through Reduced Phophorus Loading

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Lake Shaokatan Restoration Project —
Improving Water Quality Through Reduced Phophorus Loading



Lake Shaokatan is a shallow prairie lake located in western Minnesota on the South Dakota border. The lake water quality severely deteriorated in the 1980s as a result of excessive nutrient loading associated with watershed land-use practices. Nuisance algal blooms dominated the open water season and occasionally produced algal toxins alleged to have resulted in the death of dogs and cattle.

The lake has a surface area of 1,018 acres, a mean depth of 7.3 feet, and drains about 8,054 acres. The Yellow Medicine River Watershed District initiated a Clean Water Partnership project in 1990 that subsequently discovered extremely high levels of total phosphorus (average summer value of 270 g/L). Chlorophyll a concentrations were episodic with concentrations noted to exceed 100 g/L (with summer means of 20 to 30 g/L). The major source of the phosphorus was attributed to feedlot and drain tile operations within the watershed.

Assessing nutrient budgets

To counteract these problems, the watershed began an extensive monitoring program in 1991. The data were expected to help residents understand watershed nutrient loading and lake response dynamics. Using seven state-of-the-art stream measurement sites, the monitors obtained water and mass loading estimates and determined lake system balances. The basic approach was to manage the lake nutrient budget to achieve a total phosphorus goal of 90 g/L (as defined by EPA's ecoregion analyses).

Watershed restoration

After completion of the monitoring effort, a complete watershed restoration program began. Since late 1991, this program has

  • diverted a stream from a swine operation,
  • rehabilitated a feedlot-impacted wetland,
  • bought out a swine operation to eliminate it as a nutrient source to the lake,
  • upgraded a dairy feedlot operation,
  • repaired shoreline septic systems, and
  • restored four wetland complexes in the watershed.

These actions reduced phosphorus loading rates by 58 to 90 percent (over a range of years). They cost about $3 to $11 per kilogram of reduced phosphorus.

Nuisance algal blooms dominated the open water season and occasionally produced algal toxins alleged to have resulted in the death of dogs and cattle.

The watershed's responses to these corrective actions was immediate and significant as both nutrient and sediment losses were reduced. Concurrently measured average summer total phosphorus concentrations dropped from 270 to 89 g P/L by 1994. The intensity and duration of seasonal algal blooms have been curtailed with all values now less than 20 g/L.

These trends are expected to continue as the Yellow Medicine River Watershed District and local management groups continue additional watershed actions. Project monitoring is conducted mostly by farmers and others in direct contact with landowners who are most knowledgeable about land-water interactions and causal relationships between their operations and water quality.

CONTACT: Margaret Velky
Water Quality Division Watershed Assistance Section Minnesota Pollution Control Agency
(612) 296-8834



The Lake Bemidji Watershed Management Project —
Clean Water is Good for Business



The Lake Bemidji Management Project is a cooperative effort between 21 local, state, and federal groups and citizen organizations (including EPA's Clean Lakes Program). It began seven years ago with a single objective: to improve and maintain Lake Bemidji's water quality by reducing nonpoint sources of pollution.

The Lake Bemidji watershed contains more than 400,000 acres and includes the headwaters of the Mississippi River and its first major tributary, the Schoolcraft River. The City of Bemidji, justly proud of being the "first city on the Mississippi," has helped bring massive lake management changes to the watershed over the past 15 years.

Accomplishments along the way

With help from its many partners, Lake Bemidji and its city have avoided confrontation and legal proceedings. Instead, the management project has defined specific lake management goals and pursued corrective actions worth about $1 million. Examples of their accomplishments illustrate the power of a true partnership. Among other activities, the project has

  • established a state-of-the-art flow monitoring and sampling program to define river and in-lake conditions,
  • created three stormwater basins to treat runoff from downtown Bemidji,
  • installed multiple sediment traps to treat runoff from other downtown areas,
  • conducted winter litter clean-up campaigns with many cooperators (the area's a virtual city on the ice during winter),
  • rehabilitated about 400 feet of severely eroded Mississippi riverbank, and
  • revegetated a wetland on the new downtown sediment basin/Chamber of Commerce learning center (next to the historic Paul Bunyan and Babe statues).

Notwithstanding this impressive list, a crowning accomplishment may well be the project's extensive education and outreach program. The partners sponsor educational seminars, give television interviews, and teach countless secondary education classes, from which the project has drawn many student volunteers. The partners also distribute informational brochures (more than 95,000 so far), file newspaper inserts, sell placemats and bait shop clean-up bags, plant trees (more than 250,000 to date), and help develop forestry plans.

Water quality, the first and final goal

The Lake Bemidji Management Project has achieved its long-term goals for the Lake Bemidji basin. Phosphorus levels are in the 15 to 22 g/L range (down from the 30 to 40 g/L range observed in the 1970s and 1980s). Of more significance, however, is that they have also achieved widespread agreements to protect those levels. The City of Bemidji continues (without outside funding) to install sediment basins to treat urban runoff.

These commitments will help maintain the lake despite its draw of 536,000-visitor days of water-based recreation annually. Water quality and the watershed's economic health are thus intimately related. Among its other findings, the Lake Bemidji management project discovered that recreationists will seek alternative bodies of water or reduce their level of activity whenever water pollution is an issue - particularly in an area where people expect to find a "land of sky blue water." And they estimate that a 10 percent reduction of visitor activity can result in economic losses of millions of dollars per year. "Clean water," in the words of the Lake Bemidji Watershed Management Project, "is good for business."


CONTACT: Margaret Velky
Water Quality Division Watershed Assistance Section Minnesota Pollution Control Agency
(612) 296-8834

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