Crystal Bay (DNR ID: 27-0133-10)
Sampling Location GPS Coordinates: Surface Area: 800 acres Max. Depth: 113 ft
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Crystal Bay is located near the cities of Spring Park and Orono. Head east on Minnetonka Blvd, and turn left on Co Rd 101 S. Turn right at Grays Bay Blvd and continue on Bushaway Rd. Turn left on Eastman Ln/Shady Ln, then a slight right at E Circle Dr. Next take a slight left at Lake St. E. Turn left at Ferndale Rd S and continue on Shoreline Dr. Turn right at Northshore Dr. Public lake access is available at the North Arm boat access located off of Northshore Drive (Co Rd 51) two miles west from Shoreline Drive (Co Rd 15) at Smiths Bay.
Crystal Bay on Lake Minnetonka is a class 2B lake protected for aquatic life and recreation. Water quality information is available beginning in 1996. MCWD staff have been monitoring the site on Crystal Bay on a bi-weekly basis from the time of ice out (April) to the time of fall mixing (mid-October) since 2006.
Not currently available.
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. 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. An additional TP sample was taken one meter below the thermocline mixing zone once stratification developed.
| 2008 Summer Water Quality Summary |
| Parameters | Range | Mean | TSI Value | Lake Grade |
| Months | June - Sept. | May - Sept. | ||
| Secchi Depth (m) | 2.0 - 3.9 | 2.8 | 45 | B |
| Surface TP (µg/L) | 17 - 42 | 25.3 | 51 | B |
| Chlorophyll-a (µg/L) | 4 - 11 | 7.4 | 50 | A |
| Overall Score | 49 | B+ |
The following summary refers to Figure 3.11 (a-d).
- Late April to late June secchi disk depth was between 3.8 m and 4.3 m decreasing to 2.3 m in the middle of May. The remainder of the season, secchi disk depth decreased ranging from 2 m to 2.8 m (standard > 1.2 m).
- No chlorophyll-a sample was collected in late April. Throughout the season, chlorophyll-a concentrations increased ranging from 3 µg/L to 15 µg/L. Early August, early September and middle of October concentrations were greater than 10 µg/L (standard < 15 µg/L).
- Surface TP concentrations, in general, decreased throughout the season. Concentrations were below the standard (< 40 µg/L) except in late April and in the middle of August. Surface SRP were below detection limit (< 0.005 µg/L) except in late May.
- Both bottom TP and SRP concentrations gradually increased throughout the season, except in the middle of October when SRP concentrations declined.
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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