2.5.4 Wetlands

Approximately 30 percent of the land area within the Dutch Lake subwatershed is shown on the National Wetland Inventory as wetland (see Table 6). 

Table 6.  National Wetlands Inventory Wetlands in the Dutch Lake subwatershed.

Circular 39 Type

Area (acres)

Cowardin Class

Area (acres)

Seasonal

1.0

Emergent

366.1

Shallow Marsh

365.1

Forested

4.0

Deep Marsh

.6

Scrub Shrub

27.9

Open Water

165.9

Unconsolidated Bottom

166.5

Scrub Shrub

27.9

 

 

Forested

4.0

 

 

TOTAL

564.5

 

564.5

Source:  Minnesota DNR.

In 2001-2003 the District undertook a Functional Assessment of Wetlands (FAW) on all wetlands greater than one-quarter acre in size.  This assessment used a variant of the Minnesota Routine Assessment Method.  In contrast to Table 6 above, which shows wetland acreage and type from the National Wetlands Inventory completed in the 1980s, Table 7 below shows the acreage and type as assessed in the field.   Using the results of that analysis, individual wetlands were assigned to one of four categories – Preserve, and Manage 1, 2, or 3 (see Figure 12 and Table 8).  Wetlands that were evaluated as Exceptional or High on certain ecological or hydrologic values were assigned to the Preserve category.  The balance of evaluated wetlands were assigned to a category based on this assessment of current functions and values, with Manage 1 wetlands exhibiting higher values and Manage 2 and 3 moderate or lower values.   Refer to the Functional Assessment of Wetlands (2003) for details of methodology, classification, and management recommendations.

Table 7.  Dominant wetland type as assessed in the Functional Assessment of Wetlands.

Circular 39 Type

Area (acres)

Seasonal

3.9

Wet Meadow

44.0

Shallow Marsh

320.2

Deep Marsh

23.6

Open Water

13.6

Scrub Shrub

77.4

Forested

0.3

Lakes

166.8

Not typed

3.0

TOTAL

 652.8

Note: Based on field assessment.  Excludes those areas determined in the field not to be wetlands, and stormwater ponds clearly excavated out of upland.   Includes some small areas that were not field assessed.

Source: MCWD 2003 Functional Assessment of Wetlands.  See Figure 11.

Table 8.  Wetland management classifications of wetlands for the Dutch Lake subwatershed as determined in the Functional Assessment of Wetlands.

Classification

Number

Area (acres)

% of total

Preserve

14

175.6

33.8

Manage 1

30

228.5

44.0

Manage 2

39

102.0

19.6

Manage 3

14

13.2

2.6

TOTAL

97

519.3

 

Note:  The FAW excluded large lakes and wetlands less than ¼ acre in size; those areas are included in the NWI, so total will not match Tables 6 or 7.

Source: MCWD 2003 Functional Assessment of Wetlands.  See Figure 12.

The Dutch Lake subwatershed has two large riparian wetlands – on the north side and west side of the lake – that scored highly on vegetative diversity, fish and wildlife habitat, or aesthetics and thus are classified in the Preserve category (see Figure 13).

Some of the wetlands were also evaluated for restoration potential.  Factors considered were the ease with which the wetland could be restored, the number of landowners within the historic basin, the size of the potential restoration area, the potential for establishing buffer areas or water quality ponding, and the extent and type of hydrologic alteration.  There is one wetland in the subwatershed that the FAW identified as being of high restoration potential: a large Type 2 wet meadow.  Numerous other small wetlands of moderate restoration potential are located throughout the subwatershed (see Figure 14).