Wetland Classification and Mapping of the Kenai Lowland, Alaska

 

 

 

Map Unit Descriptions

 

Ecosystem: Riparian

 

Map Unit: RC

 

Extent: 13 wetland polygons; 3283.1 ha; 2.32% of wetland area; 0.08% of wetland polygons.

The RC reach of Deep Creek, the largest wetland polygon in the project area (polygon 26548).

Wetland Indicators

Type: Stream

Average depth to water table: 39.7 cm; n=11

Organic layer thickness: 18.0 cm; n=8

Average depth to redoximorphic features: 16.8 cm; n=9

Common Soils: KILLEY, TRUULI

Common Plant communities:

Barclay's willow / Bluejoint - Field horsetail

Sitka alder / Field horsetail

Barclay's Willow / Bluejoint

Barclay's willow / Bluejoint / Marsh fivefinger

 

NWI: Stream: R2US1.  Valley wetlands: PSS1/FO1&3Jn

HGM: Stream: Middle Gradient Natural Stream-single thread.  Valley wetlands: Lotic Flat/Slope groundwater-dominated Throughflow/Bidirectional-nontidal.

Accuracy assessment: 1 polygon interpreted as RC on aerial photographs was field checked.  It remained RC.

RC stream reaches are in Rosgen's (1996) C stream category.  C streams exhibit point bar formation, alternating riffles and pools, and have well-developed floodplains.  RC reaches on the lowlands are typical of larger streams such as Starisky Creek, Deep Creek and the Anchor River.  At nearly 1400 ha, the Deep Creek RC reach is the largest single wetland polygon mapped in the project area. Vegetation is diverse, as are the features found within these reaches.  Side channels, cut banks, meander scrolls and accreting terraces all contain different plant communities.  These features would be mapped as separate wetland types if they were more abundant and widespread in the project area.  Bed materials are typically gravels and cobbles.  Both flooding frequency and depth to redoximorphic features in the soil profile are key regulatory wetland criteria, although many upland inclusions occupy larger RC wetlands.

An undocumented plant community with black cottonwood (Populus balsamifera ssp. trichocarpa) as the dominant, over a thinleaf alder (Alnus incana ssp. tenuifolia) / diverse herbaceous understory is rare on the peninsula, but common along the lower reaches of  larger C streams.

Fifty foot habitat protection area

Fourteen streams in the project area are covered under Kenai Peninsula Borough's Anadromous Streams Habitat Protection Ordinance.  Many activities require a permit, or are prohibited within 50 feet of these streams.  For a list of the streams, rationale for the ordinance, and details on obtaining a permit, visit the link highlighted above.

 

Floodplain regulation

From The Kenai Borough website:

"The Kenai Peninsula Borough manages a Floodplain Ordinance that addresses proper development to reduce flood risks and lessen the economic losses caused by flood events. The ordinance provides building standards for construction projects within the floodplain to ensure the availability of flood insurance through the National Flood Insurance Program. These building requirements also are intended to minimize or prevent damage when flood events occur. The ordinance requires floodplain development permits for all projects in floodplains."


Do I Need a Permit?

 Introduction and Key to Plant Communities  

Introduction and Key to Ecosystems

    Kenai Hydric Soils    Map Unit Summary    Methods     Glossary

 

Contact: Mike Gracz
Kenai Watershed Forum 
Homer Field Office
Old Town Professional Center
3430 Main Street Suite B1
Homer, AK  99603
907-235-2218

15 November 2005 15:04