Powderhorn Lake

Powderhorn Lake (DNR ID: 27-0014-00)


MCWD Site ID: LPO01

Sampling Location - GPS Coordinates:
44.9417 N, -93.2572 W

Surface Area: 11 acres

Max. Depth: 20 ft

Directions

Site Information

Historical Information

2008 Water Quality Monitoring

2008 Data Summary

Lake Grades

 

 


Directions

Powderhorn Lake is located in Minneapolis. 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 right onto the ramp to US-12 E and continue onto US-12 E. Merge onto I-394 E and take exit 8B for I-94 W/I-94 E. Keep right at the fork, and continue onto I-94 E. Next take exit 234A for Hiawatha Ave/State Hwy 55. Merge onto Hiawatha Ave/MN-55. Turn right at E. 28th St., then a left at Cedar Ave S. Next turn right at E. Lake St. and then turn left at 13th Ave S. 13th Ave S will dead-end onto Powderhorn Terrace. Go left on Powderhorn Terrace and turn right on 14th Ave S.  Powderhorn Lake will be on the right.

Site Information

Powderhorn Lake is a shallow, polymictic class 2B lake protect for aquatic life and recreation. It has an island and one deep hole at the southeastern end of the lake. Water quality data is available back to 2002. Currently, Minneapolis Park and Recreation Board (MPRB) staff monitors the lake on a bi-weekly basis and send MCWD the raw data each fall.

Historical Information

Powderhorn Lake was named after the original shape which resembled a powderhorn. In 1890, MPRB acquired the lake and dredging was conducted from 1894 to 1904. The south end of the lake was deepened by hydraulic dredging between 1924 and 1925 and about 150,000 cubic yards of material were used to fill the north half the lake to create parkland (MPRB, 2006).

2008 Water Quality Monitoring

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 Data Summary

2008 Summer Water Quality Summary
Parameters Range Mean TSI Value Lake Grade
Months   June - Sept.   May - Sept.
Secchi Depth (m)

0.7 - 1.97

1.0

60

D

Surface TP (µg/L)

54 - 158

99.8

71

D

Chlorophyll-a (µg/L)

6.5 - 24.9

14.3

57

B

    Overall Score 62
C-

The following summary refers to Figure 2.21 (a-d).

  • Secchi disk depth decreased from late May to early July then gradually increased to 2.15 m by October.  Secchi disk depth was above the standard (> 1.2 m) from late August to October.
  • Chlorophyll-a concentrations increased from 8.8 µg/L to 48.4 µg/L by early May and decreased to 14.1 µg/L by early June. Concentrations increased to 24.9 µg/L in early July, then declined to about 6 µg/L by October (standard < 15 µg/L).
  • Surface TP concentrations increased to 158 µg/L by early June, and then decreased to 38 µg/L by October (standard < 40 µg/L). Surface SRP concentrations increased to 31 µg/L by early June then declined for the remainder of the season. 
  • Both bottom TP and SRP concentrations declined in the early season, and then slightly increased in early June. The rest of the season both TP and SRP concentrations declined.

Image - Graphs - 2008

Image - Graphs - Historic

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.

Powderhorn Lake

Water Quality Grades

2008

C-

2007

C

2006

C-

2005

C

2004

D+

2003

 

2002

 

2001

 

2000

 

1999

 

1998

 

 

 

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