Wayzata Bay (DNR ID: 27-0133-02)
Sampling Location GPS Coordinates: Surface Area: 751 acres Max. Depth: 63 ft
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Wayzata Bay is located in Wayzata. Head east on Minnetonka Blvd, and turn left on Co Rd 101 S. Turn right at Grays Bay Blvd and enter the Grays Bay Marina and public access on the left side of the road.
Wayzata Bay is on Lake Minnetonka which is a class 2B lake protected for aquatic life and recreation. Water quality information is available beginning in 1997. MCWD staff have been monitoring the site on Wayzata Bay on a bi-weekly basis from the time of ice out (April) to the time of fall mixing (mid-October) since 2006.
See Previous Reports.
Monitoring season started in late April 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. Additionally, water samples were collected within the first two meters of the surface with a 2-meter composite sampling tube. Samples one meter above the bottom were collected with a Van Doran water sampler. Surface sample were analyzed for total phosphorus (TP), soluble reactive phosphorus (SRP), total nitrogen (TN), where the bottom samples were analyzed for TP and SRP. Surface concentrations of chlorophyll-a were also analyzed and measurements of Secchi disc depth were recorded.
| 2009 Summer Water Quality Summary |
| Parameters | Range | Mean | TSI Value | Lake Grade |
| Months | June - Sept. | May - Sept. | ||
| Secchi Depth (m) | 3.3 - 4.4 | 3.9 | 40 | A |
| Surface TP (µg/L) | 10 - 24 | 15.0 | 43 | A |
| Chlorophyll-a (µg/L) | 1 - 6 | 3.3 | 42 | A |
| Overall Score | 42 | A |
The following summary refers to Figure 3.51 (a-d).
- Secchi disk depth ranged between 3.4 m and 3.5 m from late April and early June, and then increased to 4.2 m by the middle of June. Secchi disk depth decreased throughout June to 3.3 m, and then increased to 4.4 m early September (standard > 1.4 m). The rest of the season, Secchi disk depth declined.
- Chlorophyll-a concentrations remained below the standard limit throughout the entire season (standard < 14 μg/L). Chlorophyll-a increased from 6 μg/L to 9 μg/L by late May then declined to 1 μg/L by the middle of June. From late June to early October,
chlorophyll-a concentrations fluctuated between 2 μg/L and 6 μg/L. - Surface TP concentrations were below the standard limit for the entire season (standard < 40 μg/L) and fluctuated between 10 μg/L and 24 μg/L. The maximum concentration occurred in early June. Surface SRP concentrations were below detection limit (< 0.005 μg/L) except in early October (12 μg/L).
- Bottom TP concentrations ranged from 14 μg/L to 44 μg/L from late April to late June. Then from early July to late September TP concentrations increased to 461 μg/L. By early October, concentrations declined to 33 μg/L. Bottom SRP concentrations were less than 10 μg/L from late April to late June. SRP concentrations increased to 330 μg/L by late September, and then declined to 7 μg/L by the end of the season.
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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