The ridge crests act as interfluves, which separate drainage basins.  The water flowing down the valley to the left (a 1^st order stream) flows directly to the Little Tennessee River (which is behind the mountain in the left middle ground.  The waters behind the ridge in the right foreground eventually finish up in that river, but after a round-about journey of several tens of miles.  This is a view from west of Franklin, Macon County

The start of a drainage basin - a gully getting deeper and turning into a first order stream.  This is near Louisburg, Franklin County

  Basin development - 

        overland flow (sheet flow): little erosion, but minor irregularities create

             --> rills --> gullies --> stream       erosion/transport/valley development

        [this is a development process over time - and a landscape feature over space]

        newly created valley slopes may then go through same process

            influencing stream order and drainage patterns:

    Stream order

        First order stream:  one with no tributaries

            overland flow into stream from whole of drainage basin (some gullies possible)

            also subsurface flow (considered in Classes 25 & 26)

       Second order stream: downstream of junction of two first order streams

            generally greater river volume

            the drainage basin encompasses basins of both First order streams

       n^th order stream: downstream of junction of 2 (n-1)^th order streams

            must be junction of streams with same order,  inflow of one of lower order has no effect

            N.B. as order increases:

                - size of drainage basin increases (greater number of lower order basins included)

                - stream volume increases

                - reliability of stream flow increases

                    This has implications for water supply (Class 27)

The lower portion of the Cape Fear River - a high order stream draining a large area, and having a large, reliable flow.

  Drainage Patterns

   Stream density - depends on water available for runoff

      (balance between precipitation and evaporation, 

               variation throughout year & from year-to-year)

          wet climates: many streams, many small first order basins

          dry climates: few streams (many originate outside dry area)

   Drainage Patterns - (text: Fig 14-8)

       depends on stream density, amount of slope, underlying structure,

       previous geologic history:

Most of North Carolina has a dendritic pattern

Most rivers in the Piedmont have been rejuvenated.  This picture, in northern Forsyth County, is taken from the bank of the river, and shows the valley which is currently being created as a gently sloping area in the foreground.  Beyond, with the building sitting on the top edge, is the old valley wall.

(1)  Uplift of land relative to sea level: changes the stream base level.  Starting at the stream mouth, down cutting progresses upstream, creating a 'valley-within-a-valley' effect, known as a rejuvenated stream.

(2) After long period of relatively quiet conditions (on a geologic time scale), streams may have erode all of the original surface material and now flow over a structure which seems to bear no relation to the current drainage pattern.  The pattern is said to be superimposed.

(3)  During period of rock uplift (mountain building), existing streams may down cut fast enough to keep up with uplift.  Their old drainage pattern is preserved, known as an antecedent drainage pattern.

The French Broad River at Marshall, Madison County, flows in a gorge, although there are broad open valleys both upstream and downstream of this area.  The prime cause is the presence of a band of resistant rock in this area.  It is not possible to see, simply by looking at the landscape without examining the rocks very closely, whether this is a superimposed or an antecedent feature.

All landscapes are in on sense unique, but in another, this is a typical scene - the mountains and valleys in Cherokee County between Murphy and Andrews (with Cherokee County Airport on the valley floor in the center)

The mountains provide a suitable environment for the development of lakes for water supply or hydroelectric generation purposes.  They also provide recreational opportunities.  This is Chatuge Lake in Clay County

The Blue Ridge Front has always been a barrier for transportation - indicated here by a train reaching the bottom of Saluda grade, near Tryon, Polk County  

  Continental Divide - roughly along crest of Blue Ridge

        eastward flowing - Atlantic drainage

            steep, much erosion, down cut to create Piedmont

                (eroded material forming Coastal Plain rocks)

        westward flowing - Mississippi drainage

            long course to sea, less erosion, leaving mountains.\

     Process occurred from original mountain crest east of present divide

        Atlantic drainage cut back into Mississippi Drainage

Piedmont:

  Region of more extensively eroded rocks, lower elevation and more rounded hills & rolling topography

As a technical comparison:            

    relative relief - 

the altitude differences between the highest and lowest points in an area

Mountains - 300 m (1000 ft)

Piedmont - 30 m (100 ft)

Coastal Plain -3 m (10 ft)

In areas of the Piedmont where resistant rock has been encountered, upstanding remnants - Monadocks - have been left

This view is from Pilot Mountain, with Hanging Rock in the middle distance to the right, the Blue Ridge to the left in the far distance (N.B. Many North Carolina State Parks in the Piedmont are monadnocks - but NOT all).

Some areas of the Coastal Plain are well drained, with rivers in distinct valleys.  Other areas are swampy and, if they are to be used by humans, must be drained.  This drainage ditch is close to the lower Cape Fear River northeast of Wilmington.

The Coastal Plain itself is a region of low relief, with some low hills in the west, virtually completely flat in the east.