Lake Hiawatha (DNR ID: 27-0018-00)
Sampling Location - GPS Coordinates: Surface Area: 54 acres Max. Depth: 23 ft
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Lake Hiawatha is located in the city of Minneapolis. Head east on Minnetonka Blvd and turn left on Co Rd 101 S. Then turn right at Grays Bay Blvd and continue to Bushaway Rd. Turn right onto the ramp for US-12 E and keep left at the fork to continue onto US-12 E. Merge onto I-394 E and then take 8B for I-94 W/I-94 E. Keep right at the fork and merge onto I-94 E. Next take exit 234A for Hiawatha Ave/State Hwy 55 and merge onto Hiawatha Ave/MN-55. Turn right at E 38th St. and then turn left at 28th Ave S heading towards the lake.
Lake Hiawatha has an extremely large watershed due to Minnehaha Creek flowing through the lake on its route to the Mississippi River. Water quality data is available back to 1986. Currently, Minneapolis Park and Recreation Board (MPRB) staff monitors the lake on a bi-weekly basis and send MCWD the raw data each fall.
Lake Hiawatha was a shallow wetland called Rice Lake due to wild rice growing along the shores. In 1925, it was renamed after Henry W. Longfellow’s poem “Song of Hiawatha.” In the early 1900s, major alterations to the shape and depth of the lake made it more desirable for residential living. Over 1.25 million cubic yards of material were dredged in 1929. The flushing time of Lake Hiawatha is more variable compared to the other Minneapolis lakes which usually have residence times ranging in years. High creek flow into the lake lowers the residence time of nutrients and the level of algae where low creek flow into lake increases the residence time of nutrients and the level of nuisance algae (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) | 0.6 - 2.5 |
1.4 |
55 |
C |
| Surface TP (µg/L) | 46 - 112 |
75.0 |
66 |
D |
| Chlorophyll-a (µg/L) | 3.9 - 42.4 |
22.2 |
61 |
B |
| Overall Score | 61 | C |
The following summary refers to Figure 2.15 (a-d).
- Secchi disk depth increased from 0.9 m to 2.49 m from late April to early July. The rest of the season, there was an overall decline in secchi disk depth (standard > 1.2 m).
- Chlorophyll-a concentrations decreased from 21.5 µg/L to 3.9 µg/L by June, and then chlorophyll-a concentrations peaked at 42.4 µg/L by late September (standard < 15 µg/L).
- Surface TP concentrations were above the standard limit (< 40 µg/L) and peaked twice throughout the season: early June (71 µg/L) and early September (112 µg/L). Surface SRP concentrations ranged between 11 µg/L and 26 µg/L from June to July while the rest of the season, concentrations remained less than 9 µg/L.
- Both bottom TP and SRP concentrations increased until early August (TP: 155 µg/L; SRP: 57µg/L), then declined for the rest 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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