Minnesota is the “Land of 10,000 Lakes,” and our lakes are an extremely valuable resource. Monitoring water quality allows us to assess current conditions and track changes over time. Awareness of current and historical water quality helps guide lake-protection efforts and determine whether water quality is improving or declining.
Long Lake volunteers have been collecting water quality data for decades. Secchi disk readings measuring water clarity have been reported to the Minnesota Pollution Control Agency (MPCA) since 1984. In 1997 the monitoring program expanded to include total phosphorus and chlorophyll-a testing. Samples are collected monthly from May through September and analyzed by RMB Environmental Laboratories in Detroit Lakes in coordination with the Hubbard County Coalition of Lake Associations (HCCOLA).
The LLAA also contracts with the Hubbard County Soil and Water Conservation District (HCSWCD) to measure dissolved oxygen and temperature at the deepest point in the lake (Site 202). These measurements help us understand fish habitat conditions and seasonal changes within the lake. Water monitoring fees are supported through donations to the LLAA Foundation.
Water Quality Reports
2020 Long Lake Water Monitoring Trend Analysis (10-Year Review)
Our water quality analysis uses data from RMB Environmental Laboratories’ “Lakes Database.” We thank the volunteer citizen scientists who have collected samples following MPCA laboratory protocols since 1997 as part of the Hubbard County Coalition of Lake Associations (HCCOLA) monitoring program.
Information from the DNR Infested Waters List, MPCA Lake Finder, and the MPCA Lake Dashboard is also included.
Long Lake Report: 20 Years in Depth
This report from RMB Environmental Laboratories contains water quality data through 2016.
Total Suspended Solids (TSS) are also monitored by Long Lake water quality volunteers. TSS refers to the particles suspended in the water that can affect clarity and overall lake health. These particles include clay, silt, sand, algae, decaying vegetation, and pollen. TSS is a combination of organic suspended solids (TSVS) and inorganic suspended solids. While pollen is a component of TSS and can decrease clarity, it has minimal impact on lake water quality because it becomes waterlogged and sinks to the bottom after a relatively short time, adding very little nitrogen to the lake.
RMB Environmental Laboratories explains that TSS is made up of two general types of material:
• Organic Suspended Solids (TSVS – Total Suspended Volatile Solids)
These consist primarily of living or decaying plant material in lakes.
• Inorganic Suspended Solids
These consist mainly of soil particles and other mineral material that enter the lake through runoff after rain events.
While pollen may temporarily reduce water clarity, it typically sinks quickly and contributes very little nitrogen to the lake.
Each season the Long Lake water quality monitoring team collects samples monthly from May through September. Monitoring takes place at Long Lake Site 202 near the deepest part of the lake. Water samples are placed in designated bottles and sent to RMB Environmental Laboratories for analysis.
The monthly TSS measurement helps us understand how runoff and shoreline erosion affect water clarity. Results can highlight the importance of shoreline restoration, rain gardens, and buffer zones that help keep runoff on land longer and filter water before it enters the lake.
Collected Data Conclusions and Strategies
This report by the Hubbard County Soil and Water Conservation District along with RMB Environmental Laboratories is based in part on historical data collected by LLAA members in water quality monitoring tests done from 1984 through 2011. It is the report which Mark Sommer, SWCD, referenced in his presentation at the 2012 LLAA Annual Meeting.
Dissolved Oxygen/Temperature Profile for Long Lake
The Hubbard Soil & Water Conservation District (SWCD) Hydro Lab is used by Long Lake water quality volunteers to measure dissolved oxygen (DO) and temperature at the deepest point in the lake (Site 202). Measurements began in May 2012.
These charts help us understand fish habitat conditions throughout the water column. Cisco, a cold-water fish species and an important forage fish for walleye, are especially sensitive to low oxygen and warmer water temperatures. Because of this, they act as a “canary in the coal mine,” helping scientists understand how changing lake conditions affect fish habitat.
