Transcript Methods of Wetland Creation and Restoration

Wetland Conservation
Approaches
Kevin L. Hoover
Water’s Edge Hydrology, Inc.
[email protected] – http://wehydro.com
“Wetland Triangle”
Hydrophytic
Vegetation
Water and Soils
Support Plants
Wetland
Hydrology
Water Makes Soils Hydric
Soils Retain Water
Hydric
Soils
Wetland Conservation
Categories
• Creation – conversion of existing uplands to
wetlands.
• Restoration – recovery of historic wetlands from
current disturbed or upland conditions.
• Enhancement – improving the functions and
values of wetlands.
• Preservation – protection of wetlands from
existing or potential future impacts.
Implementation Approaches
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Earthwork Methods
Hydrologic Improvements
Soil Amendments
Vegetative Management
Habitat Improvements
Earthwork Methods
• Excavate or fill upland areas to expand existing
wetlands or create new wetlands.
• Remove historic fills to re-expose buried
wetlands.
• Make the area flat overall, but leave the ruts.
• Apply fluvial geomorphology to create flood bank
wetlands and sloughs.
• Install subsurface barriers on sloped sites.
Hydrologic Improvements
• Disrupt artificial drainage where present.
• Eliminate historic upstream diversions.
• Create impounding structures to increase the
spread of hydrology.
• Decrease depths of open water areas (6” or less is
optimal for emergent vegetation).
Soil Amendments
• Organic content is essential to good plant growth
and water retention.
• Disturbed wetlands may have lost their organic
surface soil horizons, exposing low-organic
mineral soil.
• New topsoil may be added to improve conditions.
• Alternately, organic matter may be tilled into the
mineral soil.
• Composted organic matter, such as manure or leaf
litter, makes the best amendment.
Organic Content of Natural Vs. Created Wetlands
Soil Organic Matter
25%
20%
15%
10%
5%
0%
Natural Wetlands
Created Wetlands
Vegetative Management
• Fence off livestock and exclude vehicular traffic
along riparian corridors to allow recovery of
vegetation and soil disturbances.
• Remove invasive species and seed or plant with
native species.
• Plant woody species along riparian corridors.
• Plant adjacent uplands for fringe habitat.
• Consider forage, nesting, and escape cover when
selecting species.
Habitat Improvement
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Bird boxes, nesting platforms, “loafing” rafts, etc.
Brush piles and snag trees.
Migration-friendly culverts.
Create connections between existing wetlands as
migration corridors.
North Corner Site
• Restoration of historic wetlands by blocking off
agricultural drainage ditches.
• Enhancement of marginal wetland areas by
improved hydrology.
• Creation of new wetlands by excavation and
impoundment.
• Preservation of existing wetlands and upland
habitat.
Antwerp Site
• Enhancement of existing wetlands by improved
hydrology.
• Creation of new wetlands by excavation and
impoundment.
• Protection of wetlands by access restrictions and
earthwork buffers.
• Planting of adjacent upland areas for habitat
improvement.