Langdon Lake (DNR ID: 27-0182-00)
Sampling Location - GPS Coordinates: Surface Area: 144 acres Max. Depth: 38 ft
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Langdon Lake is located in the city of Mound off Hwy 110. There is currently no public access to the lake.
Langdon Lake is a dimictic class 2B lake protected for aquatic life and recreation. Limited water quality information is available beginning in 1976, but regular seasonal sampling did not begin until 1997. It is currently listed as an impaired water body by the MPCA for mercury in fish tissues. MCWD staff have been monitoring the lake on a bi-weekly basis from the time of ice out (April) to the time of fall mixing (mid-October) since 2006.
Currently not available.
Monitoring season started in early May and ended in late October. A YSI multi-probe sonde was used to measure dissolved oxygen (DO), temperature (oC), pH, and specific conductivity (µS/cm) at each meter depth from the water surface to the bottom. Water samples were collected at one meter below the water surface and one meter from the bottom. Surface sample parameters analyzed included total phosphorus (TP), total nitrogen (TN), and soluble reactive phosphorus (SRP). Surface concentrations of chlorophyll-a were also analyzed and measurements of Secchi disc depth were recorded. Bottom samples were analyzed for TP and SRP.
| 2008 Summer Water Quality Summary |
| Parameters | Range | Mean | TSI Value | Lake Grade |
| Months | June - Sept. | May - Sept. | ||
| Secchi Depth (m) | 0.35 - 0.7 | 0.5 | 69 | F |
| Surface TP (µg/L) | 115 - 195 | 166.0 | 78 | F |
| Chlorophyll-a (µg/L) | 47 - 148 | 84.0 | 74 | F |
| Overall Score | 74 | F |
The following summary refers to Figure 8.3 (a-d).
- Secchi disk depth slightly decreased from 0.8 m in May to 0.45 m in August. The rest of the season secchi disk depth increased from 0.5 m to 0.7 m but remained below the standard (1.2 m).
- Chlorophyll-a concentrations fluctuated in the early season then increased to 148 µg/L by late July. Concentrations declined for the remainder of the season. Chlorophyll-a surpassed the standard (< 15 µg/L) for the entire season.
- Surface TP concentrations fluctuated between 100 µg/L to 170 µg/L from May to June. Concentrations continued to fluctuate, but the range increased from 150 µg/L to 200 µg/L. TP concentrations surpassed the standard (< 40 µg/L) for the entire season. Surface SRP concentrations were mostly below detection limit with the highest concentration occurring in early September (14 µg/L).
- Both bottom TP and SRP concentrations steadily increased until September, when concentrations sharply decreased. The rest of the season phosphorus concentrations remained consistent.
Lake Grades and Historical Monitoring Summaries
When available, previous reports are linked to applicable year. Additional lake data previous to 2007 may be available in the applicable year's hydrodata report. If you have additional questions or you are looking for specific information please contact MCWD's Water Quality Staff.
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