Drainage Patterns, Landscapes of NY and the Affects of Human

Activites

Rocks that are durable resist weathering and erosion

Durable rocks form the higher portions of a landscape (ex. plateaus, mountains, and cliffs)

Softer rock erodes faster than harder, durable rock

If layers of a hill differ in durability, the softer rocks will wear away faster, giving the hill an uneven or stepped appearance

Drainage patterns are determined by the way tributaries join to form larger streams

Streams tend to follow zones of weaker rock because they erode into valleys

Dendritic/ Random: Develops in horizontal rock layers with little difference in resistance

Rectangular/Trellis: Observed in folded, faulted and jointed rocks with much difference in resistance

Radial- occurs on domed landscapes with little difference in resistance, like volcanoes- looks like spokes of a wheel

Annular: A pattern of concentric circles found in areas of domed structure with much difference in rock resistance

Farming and construction projects can increase erosion

Contour plowing curves around a hill, rather than up and down the hillside, helping to slow water runoff and erosion.

Strip mining removes layers of soil to dig up minerals found in bedrock.

When finished, engineers can even out the land, replace the soil and add plants

People move more soil and rock than all rivers combined!

St. Lawrence/Champlain Lowlands: low-lying plain along the St. Lawrence River and Lake Champlain

Adirondack Mountains: only true mountain region in NYS made up of resistant rocks

Appalachian Uplands: NY’s largest region that is mostly flat layers of sedimentary rocks. Used to be the bottom of an ocean, pushed up over the years

The Finger Lakes: formed by a continental glacier which deepened and widened pre-existing valleys. As the glaciers melted, the till blocked outlets to the south forming the lakes

The Erie-Ontario Lowlands: lie south of the Great Lakes with NY borders. Although it is a plains landscape, these lowlands have many hills composed of unsorted glacial till. Good soil, deposited and mixed by glaciers, and a climate moderated by the lakes makes this an important agricultural area

Tug Hill Plateau: small region of elevated sedimentary rock layers. Poor drainage caused by glacial deposits and abundant winter snowfall make this one of the least-inhabited areas in the state

Hudson-Mohawk Lowlands/Plains: Follows a zone of easily eroded limestones and shales

New England Highlands: a region of intensely folded and faulted metamorphic rocks.

Triassic Lowlands: a section of sandstones and shales deposited in a fault basin. This region is geologically younger than the surrounding highlands. An intrusion of basaltic magma was eroded by the Hudson River, forming the high cliffs of the Palisades.

Atlantic Coastal Plain: largely composed of glacial sediments. The land south of the moraines of LI is composed of sorted material wasted out of glaciers.