Water quality study results: Many area lakes 'exceptional,' others cause concern
Second tier development and agriculture appear to be the biggest threats to water quality in Otter Tail County, according to the results of a new study released last week. Overall, most of the lakes involved in the study were found to be of "exceptional" quality, while a few were cause for concern.
The study, funded by the county's Soil and Water Conservation District, the Minnesota Board of Water and Soil Resources, and local lake associations, looks at 21 of the areas larger, more developed lakes to determine overall water quality trends as well as data quality and any gaps in data.
It looks at a number of factors involved in water quality, including phosphorus and chlorophyll concentrations, transparency and aquatic invasive species infestations.
By compiling and analyzing 10-15 years' worth of data and information collected from various sources - including the DNR, the Minnesota Pollution Control Agency, the Otter Tail County Coalition of Lake Associations and individual lake associations - the study offers a summary of the current state of large lakes in the county, and makes recommendations for maintaining or restoring water quality in the future.
The study was the focus of a Water Quality Summit held in Ottertail last week, which drew a crowd of about 70 people.
According to a summary of the study's findings, many of the assessed lakes are "exceptional water resources," including East Silent, Seven, Little McDonald, Eagle, Clitherall, West Battle, Pelican and Fish lakes. Most of these are also improving in water quality.
For these lakes, maintaining at least the current level of water quality is considered "imperative." The lakes should be protected from new disturbances, and any new developments should follow county ordinances, include proper shoreline buffers and minimize impervious surfaces, researchers recommend.
Other lakes were found to be of greater concern, including Big and Little Pine, Walker and Wall lakes. These lakes have the Otter Tail River flowing through them, a high degree of agriculture in their lakesheds, and the city of Perham nearby, all of which pose challenges to water quality.
"Second tier development and agriculture seem to be the largest overall risks to the lakes," according to the study. "Once the second tier is developed, the drainage in the lakeshed significantly changes and more runoff reaches the lake from impervious surface and lawns."
Researchers suggest installing proper vegetative buffers around these lakes and upstream in the river watershed to help protect against runoff. Other measures, such as rain gardens around the lakes and in Perham, wetland restoration, conservation easements, smart development and septic system maintenance, were also recommended.
Swan and Round lakes were also found to be of concern; Swan for a high level of disturbance in the watershed, and Round for its declining trend in transparency. The study suggests shoreline restoration and rain gardens be implemented at both these lakes.
Most of the lakes included in the study were found to have a realistic chance for full restoration of water quality and improved quality of fish communities, provided the appropriate measures are taken. Three of them - East Silent, Seven and Round lakes - were found to have an excellent chance of this. Two others - Wall and Swan - would require more expensive efforts to be restored.
Moriya Rufer, of RMD Environmental Laboratories, Inc., which conducted the study, gave an overview of the lake assessments at the Water Quality Summit.
She said RMD has completed lake and lakeshed assessment reports for 12 counties in Minnesota. In areas near the Twin Cities, she said, the focus of future water quality efforts is on restoration, whereas in Otter Tail County it's more about protection.
Otter Tail County has a high number of lakes (about 60) that have enough data to make a trend analysis possible, she said, adding, "No other county in Minnesota has that much data - kudos to volunteers for collecting samples all those years (there needs to be at least 10 consecutive years of phosphorus and chlorophyll data to enable trend analysis)."
"We've got great lake associations, an active Coalition of Lake Associations, and I think we're doing some really great things," added Darren Newville of the East Otter Tail Soil and Water Conservation District. "We've got some great things going in Otter Tail County."
Newville said the results of this study would be shared with individual lake associations on request. Lake associations may also get assistance applying for grants for future water quality projects.
For more information, visit www.eotswcd.org, follow the link to East Otter Tail County, and click on the 'Shore and Water' tab.