Harrisons Bay (DNR ID: 27-0133-14)
Sampling Location GPS Coordinates: Surface Area: 211 acres Max. Depth: 46 ft
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Harrisons Bay is located near the city of Mound. Head east on Minnetonka Blvd, and turn right on Co Rd 101 S. Turn right MN-7 and turn right on Oak St which merges into Smithtown Rd. Continue onto Manitou Rd/Shadywood Rd and take a slight left to stay on Manitou Rd/Shadywood Rd. Next turn left at Shoreline Dr. Public boat launch is on the left.
Lake Minnetonka 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 Harrisons Bay 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 began 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. Water samples were collected at one meter below the water surface and one meter from the bottom. Surface and bottom sample parameters analyzed included total phosphorus (TP), total dissolved phosphorus (TDP), soluble reactive phosphorus (SRP), total nitrogen (TN), total dissolved nitrogen (TDN), nitrate/nitrite (NO3/NO2) and ammonia (NH4). Surface concentrations of chlorophyll-a were also analyzed and measurements of secchi disc depth were recorded.
| 2008 Summer Water Quality Summary |
| Parameters | Range | Mean | TSI Value | Lake Grade |
| Months | June - Sept. | May - Sept. | ||
| Secchi Depth (m) | 0.4 - 2.3 | 0.9 | 62 | D |
| Surface TP (µg/L) | 39 - 67 | 54 | 62 | C |
| Chlorophyll-a (µg/L) | 11 - 94 | 48.2 | 69 | C |
| Overall Score | 64 | C- |
The following summary refers to Figure 3.19 (a-d).
- Secchi disk depth was above the standard (> 1.2 m) from late May to late June and less than 0.95 m for the rest of the season.
- Chlorophyll-a concentration was 154 µg/L in late April and decreased to 10 µg/L by late May. The rest of the season there was an overall increase in chlorophyll-a concentrations with the maximum concentration (94 µg/L) occurring in early September (standard < 15 µg/L).
- Surface TP concentrations decreased from 58 µg/L to 28 µg/L in the beginning of the season (standard < 40 µg/L). An overall increase occurred from late May to October with TP concentrations reaching a maximum (81 µg/L) in October. Surface SRP concen-trations were below detection limit (< 0.005 µg/L) except in late April and late May.
- Bottom TP concentrations declined from late April to late June then peaked in late July (617 µg/L). The rest of the season concentrations ranged between 51 and 91 µg/L. Bottom SRP concentrations were between <0.005 µg/L and 8 µg/L except in early August (42 µg/L). No results for late July due to bottom SRP sample arriving to the Lab empty.
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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