More than half of Twin Cities west metro lakes get a passing grade

Despite record flooding last year, more than half of west metro area lakes, bays and ponds got a passing grade in an annual report.

The Minnehaha Creek Watershed District released its 2014 report this week, with 21 lakes and bays graded in 2013 getting a higher grade, while 15 lakes and bays saw a lower grade and 21 stayed the same.

The 11th annual report is done by the watershed district, Three Rivers Park District, Minneapolis Park and Recreation Board and citizen monitors, looking at data on water clarity, algae growth and nutrients collected from last May to September. Each lake and bay gets scores, which are averaged to determine a grade from A to F. A grade of C is typical of lakes in the seven-county metropolitan area, according to the watershed district.

"People really depend on these to rate the water quality in their community," watershed district spokeswoman Telly Mamayek said. "They are important … but we've always cautioned that they're a snapshot in time."

Only one F was given out — Lundsten Lake South in Victoria — because it didn't meet all eutrophication standards. In Minneapolis, Lake Calhoun got an A, Cedar Lake got a B, Lake of the Isles got a C+, Lake Harriet got a B+ and Nokomis got a B-. On Lake Minnetonka, nine bays got As, while 5 bays got Ds.

However, not all lakes and bays were graded last year. The record rainfall and flooding didn't appear to impact lakes' quality much, though Mamayek said the report doesn't usually show a dramatic shift. "It takes time to impact a lake's water quality," she said.

The watershed district is now developing a more holistic grading system for 2017 that includes more than three factors. For more information or to read the full report, go to minnehahacreek.org/data-center/mcwd-lake-grades.

KELLY SMITH