Grass Lake (DNR ID: 27-0681-00)
Sampling Location - GPS Coordinates: Surface Area: 27 acres Max. Depth: 4.9 ft
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Grass Lake is located in Minneapolis. Head east on Minnetonka Blvd toward Shavers Lake Road. Turn left at McGinty Rd W and turn right to merge onto I-494 South. Take exit 13 for State Hwy 62/Co Hwy 62. Turn left at W 62nd St/County Rd 62/MN-62 and continue to follow MN-62. Take the Penn Ave exit toward Co Hwy 32 and turn left at Penn Ave S. Turn right at W 60th St and take a slight left at Grass Lake Terrace. The lake will be on your right hand side located in Minneapolis.
Grass Lake is type 5 wetland and is known as a good bird watching location (MPRB, 2006). It is protected for aquatic life and recreation and has water quality data going back to 1997. Currently Minneapolis Park and Recreation Board (MPRB) staff monitor the lake on a bi-weekly basis and send MCWD the raw data each fall.
Grass Lake was more than double its current size as it was a section of Richfield Lake and was separated due to the construction of State Highway 62. Minneapolis Park system does not include Grass Lake, but in 2002, MPRB included Grass Lake into its monitoring program (MPRB, 2006).
Monitoring season started in early May and ended in late October by MPRB. Hydrolab mini-sonde 5 multi-probe measured dissolved oxygen (DO), temperature (oC), pH, and specific conductivity (µS/cm) at each meter depth from the water surface to the bottom. Surface water samples were a composite of the first two meters below the surface. Surface sample parameters analyzed are extensive; MCWD is concerned with total phosphorus (TP), total nitrogen (TN), and soluble reactive phosphorus (SRP). Surface concentrations of chlorophyll-a were also analyzed.
| 2008 Summer Water Quality Summary |
| Parameters | Range | Mean | TSI Value | Lake Grade |
| Months | June - Sept. | May - Sept. | ||
| Secchi Depth (m) | n/a |
n/a |
||
| Surface TP (µg/L) | 38 - 83 |
55.0 |
62 |
C |
| Chlorophyll-a (µg/L) | 2.4 - 9.5 |
6.2 |
49 |
A |
| Overall Score | 55 |
B |
The following summary refers to Figure 2.9 (a-c).
- No secchi disk depth data was collected for Grass Lake.
- Chlorophyll-a concentrations decreased from 10.2 µg/L to 2.38 µg/L from late April to June and then increased to 9.54 µg/L by July. From August to October concentrations ranged between 6.2 µg/L and 6.6 µg/L (standard < 15 µg/L).
- Surface TP concentrations decreased from 62 µg/L to 49 µg/L from late April to May, and then increased to 83 µg/L by June. The remainder of the season there was an overall decrease in concentrations that ranged from 38 µg/L to 57 µg/L (standard < 40 µg/L). Surface SRP concentrations were less than 12 µg/L for the majority of the season except in June (33 µg/L).
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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