ESCI 199 Exam 3

Watershed

Area of land where all the water drains into the same place, divided by some area of elevated terrain

Drainage System

Includes streams and the area they flow through, from headwater to mouth

Endorheic/closed basins

Basins completely surrounded by higher elevation, meaning that water can only be removed from evaporation or going into the ground

Dissolved Load

Ions dissolved in a river/stream

Suspended load

small particles flowing with the river

Bed load

Sediment transported across the bottom of a river via hopping/rolling

Base Level

Lowest level to which a stream can erode. All streams are trying to get to either a local (e.g. reservoir) or ultimate (e.g. ocean) base level

Hydraulic Sorting

Sorting of different grain sizes by flow and density. Stuff that is less dense, smaller, and has a flakier shape are easier to transport with lower energy

Depositional Features

Places associated with streams where sediment is deposited e.g. bars, deltas, alluvial fans, braided streams

Flood

Water inundates areas that are normally dry

Recurrence Interval

How often a particular discharge is expected to repeat itself. A “100-year” flood has a 1% chance of happening in any given year

Factors Impacting Floods

Nature of precipitation event (seasonal effects, intensity, duration), ground conditions (infiltration capacity, vegetation cover)

Ocean Salinity

3.5% or 35 per mill

Salinity impacted by:

Water content of solution (melting of ice, evaporation, freezing of ice, precipitation), latitude (less salty at equator due to increased precipitation from low pressure systems), season

Thermocline

Rapid change of temperature with depth at lower latitudes, creating a barrier in the ocean columns of what kind of life you can find where

Pycnocline

Rapid change of density with depth due to lower temperatures. Occurs at lower latitudes

Active Continental Margin

Continental slope descends abruptly into deep-ocean trench because it’s on a plate boundary. Narrow continental shelf, common in the Ring of Fire

Passive Continental Margin

Margins not along plate boundaries, meaning there are few earthquakes/volcanoes and wide continental shelves. Common along Atlantic coasts

Abyssal Plains

Sites of thick accumulation of sediment along deep-ocean basins

Seamounts

Isolated volcanic peaks rising above the surrounding seafloor

Marine Snow

Little dudes who have mineralic skeletons that die and their skeletons go out to the deep ocean to create seafloor sediment

Ocean Currents

Masses of water that move from 1 place to another. Surface currents develop from friction between the wind and the ocean surface. Move heat from low latitudes to polar regions

Coriolis Effect

Deflection of surface currents due to Earth’s rotation. Moves objects to the right in the Northern Hemisphere and to the left in the Southern Hemisphere

Coastal Upwelling

Rise of cold, nutrient-dense deep water to replace warm surface water

Deep-Ocean circulation is driven by

Density differences (thermohaline circulation) throughout the entirety of the world’s oceans

Erosional features include

Wave-cut cliffs, wave-cut platforms, marine terraces

Erosional features associated with headlands

Sea arch, sea stack

Emergent Coast

Tectonic uplift of the land leads to a drop in sea level and erosional features like marine terraces

Submergent Coast

The land adjacent to the sea subsides or sea level rises, leading to depositional features

Depositional features include

Spit, baymouth bar, tombolo

Barrier Islands

Common along Atlantic and Gulf coasts, islands parallel to the shore

Breakwaters

Man-made barriers built offshore and parallel to the shore to protect boats from breaking waves

Groins

Barriers built at a right angle to the beach to trap sand

Seawalls

Armors coast against breaking waves, but often lead to increased erosion on the seaward side

Alternatives to Hard Stabilization

Beach nourishment (adding sand) or moving buildings away from beaches