3/2/2015

Physiography

What can we learn from physiography when it comes to environmental land‐ use planning and surface water conservation?

Physiography ‐ Regions

• Physiographic regions are defined by the composite patterns of the main elements of landscape: – Landforms – Drainage features – Soils – Climate – Vegetation – Land‐use

• Describing physiographic regions is hierarchical, beginning usually with the major (geologic) structural divisions

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Physiography ‐ Regions • There are 10 general physiographic regions of the U.S.A. and Canada

– Canadian Shield – Appalachian Mountains – Interior Highlands – Atlantic Coastal Plain – Interior Plains – Rocky Mountain Region – Intermontane Region – Pacific Mountain System – Arctic Coastal Plain – Alaska‐Yukon Plain

Physiography ‐ Provinces

• Each region is then broken down into smaller parts, called provinces http://wmc.ar.nrcs.usda.gov/technical/images/phys.gif

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Physiography ‐ Provinces

• Let’s look at the Appalachian Province:

– Blue Ridge – Piedmont – Ridge and Valley – Appalachian Plateaus – Northern Appalachians

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Physiography ‐ Sections

• Physiographic provinces are further broke down into sections • The physiographic sections of the Appalachian Plateaus Province are: – Northwestern Glaciated Plateau – High Plateau – Pittsburgh Low Plateau – Waynesburg Hills – Allegheny Mountain – Allegheny Front – Deep Valleys – Glaciated High Plateau – Glaciated Low Plateau – Glaciated Pocono Plateau

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Physiography ‐ Sections

• Each physiographic section is differentiated by particular ‘landscape level’ features (although I don’t like using that phrase…) • Features include: • Dominant topographic form • Local relief • Underlying rock type • Geologic structure • Approximate elevation (Min. and Max.) • Drainage pattern • Boundaries • Origin • Let’s look at the Pittsburgh Low Plateau and the Allegheny Mountain

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Site

What is the ‘site’?

• What we call a ‘site’ is the specific piece of earth we are dealing with in the plan

• It can be: – A parcel of land – A municipality – A stream corridor – A watershed

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Always think of the site in three dimensions

The site is a piece of real estate that extends above and below the land surface

This Not this

Site and Physiography The very first step when assessing site is to determine physiography and to think about the characteristics of the section

Pittsburgh Low Plateau Section Allegheny Mountain Section

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Allegheny Mountain Section

• ridges decrease in elevation from south to north and the ridges have no topographic expression at the north end of the section • broad, rounded ridges separated by broad valleys

• ridges decrease in elevation from south to north and the ridges have no topographic expression at the north end of the section • broad, rounded ridges separated by broad valleys

http://www.marcellus-shale.us

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