Transcript Isolated Wetlands

Isolated Wetlands
Hydro-geo Developmental
Factors of Isolated Wetlands
Developmental Factors
 SWANCC v. US Army Corps of Engineers
 Geological Factors
 Hydrological Factors
 Isolated wetlands?
SWANCC v. US Army Corps
of Engineers
 Ruling made regulation of many isolated
wetlands out of jurisdiction of the USACE
 New definition of isolated wetland’s
relevance needed
 So why do I have to listen to you talk about
water and rocks?
Geological Development of
Wetlands
 Glacial wetlands
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10,000+ years ago N. Am covered in glaciers
 Aeolian Wetlands
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Scouring of wind over time
 Other geological factors
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Range from topographical depressions to make-up of the
soil strata
Glacial Wetlands
 Prairie Potholes
 10,000 yrs ago Wisconsin Glacier retreated
 Stretch from North Dakota to Montana then south into
Texas
 Channeled Scablands
 Collapse of glacial ice dams
 Mainly in Cascade Mountain Region of Pacific NW
 ~85% are considered isolated
Aeolian Wetlands
 Nebraska Sandhills
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60% isolated (317,400 ha of a total 529,000 ha)
 Playas
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cover the Southern High Plains between Texas and New Mexico
Aeolian forces scouring out shallow, circular, flat bottomed basins
calcium in the soil is dissolved by water collection
 Rainwater Basin
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cover the Southern High Plains between Texas and New Mexico
90% of them geographically isolated
silty loess plains
Other Geological Factors
 Great Lake Alvar Wetlands
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Shallow bedrock
 Topographical Depressions
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salt flats, costal plains and pocosins
Perched clay layers
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Build up of fines
Hydrological Development of
Wetlands
 Karst Basin
 Calcium and Dolomite in soil carried away by GW
 Cypress Domes
 Sinkhole wetlands
Karst Basin Wetlands
 Cypress Domes
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Swampy Woodlands (cypress, duh…)
Sustained by precipitation run off and long
retention times
 Sinkhole Wetlands
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Intricate system of underground fissures and
streams.
Isolated Wetlands?
 Defining “isolated”
 Looking at spatial and temporal relations