Lake Harriet (DNR ID: 27-0016-00)
Sampling Location - GPS Coordinates: Surface Area: 353 Acres Max. Depth: 82 ft
|
|
|
Lake Harriet is located in the city of Minneapolis. Go East on Minnetonka Blvd and turn left on McGinty Rd W. Then turn right to merge onto I-494 S. Take exit 13 for State Hwy 62/Co Hwy 62. Turn left at W 62nd St/Co Rd 62/MN-62 and continue to follow MN-62. Then take the Penn Ave S exit towards Co Hwy 32. Turn left at Penn Ave S. Then turn right at E Lake Harriet Blvd/E Lake Harriet Pkwy. Turn left to stay on E Lake Harriet Blvd/E Lake Harriet Pwky towards the lake.
Lake Harriet is a deep, glacial kettle lake and generally remains stratified throughout October (MPRB, 2006). Water quality data is available from 1979 and currently, Minneapolis Park and Recreation Board (MPRB) staff monitors the lake on a bi-weekly basis and sends MCWD the raw data each fall.
Lake Harriet was named after Harriet L. Leavenworth, wife of Colonel Leavenworth. 360 acres of the Lake Harriet and 55 acres of the surrounding areas were donated to the MPRB by Colonel W.S. King in 1885, while the rest of the lake was acquired from 1883-1898 and 1921. A marshland on the northeast corner of the lake was filled to make room for the parkway while the northern portion of the lake is now Robert’s Bird Sanctuary. Lake Harriet and Calhoun were connected by pipeline and a pumping station; however, the pumping station was abandoned and flow between the two lakes occurs via gravity. A fixed weir at the southern edge of Lake Harriet allows discharge into Minnehaha Creek (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 while bottom water samples were collected one meter from the bottom. Additional discrete samples were collected throughout the thermocline mixing zone once stratification developed. 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 and measurements of Secchi disc depth were recorded. Thermocline and 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) | 0.98 - 2.8 |
1.9 |
51 |
B |
| Surface TP (µg/L) | 16 - 34 |
24.5 |
50 |
B |
| Chlorophyll-a (µg/L) | 4.8 - 14.9 |
9.0 |
52 |
A |
| Overall Score | 51 |
B+ |
The following summary refers to Figure 2.13 (a-d).
- Secchi disk depth increased from 2.5 m to 4.9 m from late April to late May and then decreased to 0.98 m by early July. By October, secchi disk depth increased to 3.6 m (standard > 1.2 m).
- Chlorophyll-a concentrations peaked three times throughout the season: early June (13.6 µg/L), early July (14.9 µg/L) and October (11.4 µg/L). Throughout the rest of the season chlorophyll-a concentrations ranged between 3.8 µg/L and 9.4 µg/L (standard < 15 µg/L).
- Overall, surface TP concentrations decreased throughout the season ranging from 16 µg/L to 44 µg/L (standard < 40 µg/L). Surface SRP concentrations peaked at 11 µg/L in early August.
- Both bottom TP and SRP concentrations declined early, and then increased throughout the season. From June to July, SRP fluctuated from 87 µg/L to 11 µg/L to 155 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.
|
|
Links to PDF documents in this site require Adobe Acrobat Reader, which you can download for free by clicking on the image below. (this will open in a separate browser window)
