River Environments Flashcards

Flashcards about River Environments

Upper Course

The section of a river that begins as narrow tributaries converging to form a V-shaped valley, characterized by steep gradients, rapid water flow, and significant vertical erosion.

Rapids and Waterfalls

Common features in the upper course of a river due to steep topography.

Middle Course

The section of a river where the channel becomes deeper and rounder, leading to increased erosion, widening of the channel, and development of floodplains.

Lower Course

The section of a river that carries the most substantial volume of water within a wide, deep channel, featuring levees and a shallower gradient.

Vertical Erosion

The process that deepens the riverbed, particularly in steep sections.

Lateral Erosion

The process that widens the riverbanks, creating more expansive channels.

Abrasion

The erosional process where rock fragments carried by the water scrape against the river channel.

Attrition

The erosional process involving colliding rocks and pebbles being broken down into smaller, smoother particles.

Hydraulic Action

The erosional process where the force of high-pressure water fractures and collapses riverbank material.

Corrosion (Solution)

The erosional process where certain minerals in rocks dissolve into river water, especially in acidic environments.

Solution (Transportation)

The transportation process where chemicals are fully dissolved in water and transported invisibly.

Suspension

The transportation process where tiny solid particles are held within the water and transported, often resulting in cloudy water.

Saltation

The transportation process involving larger pebbles that bounce along the riverbed.

Traction

The transportation process where large rocks and boulders are rolled along the riverbed.

River Deposition

The process that occurs when river water loses energy and velocity, leading to the dropping of its load.

Interlocking Spurs

Formations in the upper course where the river is forced around harder, resistant rocks, creating a zigzag pattern.

Waterfalls

Formations where there is a sudden change in rock resistance, causing water to cascade dramatically over ledges.

Gorge

A narrow valley with steep, rocky walls formed by the gradual erosion and retreat of a waterfall.

Meanders

Pronounced bends in a river, formed through lateral erosion on the outer bends and deposition of sand on the inner bends.

River Cliff

The outer bend of a meander where faster water flow leads to erosion.

Slip-off Slope

The inner bend of a meander where slower water allows sediment to accumulate.

Thalweg

The path of the fastest water flow in a river, providing insights into erosion and deposition patterns.

Ox-Bow Lakes

Crescent-shaped lakes formed when river meanders become severely eroded and sediment blocks the former bend.

Floodplains

Fertile areas that develop from sediment deposition during floods, making them suitable for agriculture.

Levees

Raised banks that protect against flooding, formed by sediment accumulation when the river overflows.

Estuaries

Depositional environments formed at river mouths where freshwater mixes with saltwater, creating diverse ecosystems.

Storm Hydrographs

Graphs that depict how river discharge changes over time in response to precipitation.

Peak Precipitation

The highest amount of rainfall recorded during a storm event.

Rising Limb

The phase where river discharge increases following rainfall.

Peak Flow

The maximum discharge measured after the peak rainfall.

Lag Time

The duration between peak rainfall and peak river discharge.

Falling Limb

The period during which discharge levels decrease as rain ceases.

Base Flow

The return to normal discharge levels post-rainfall.

Flash Floods

Floods that occur suddenly with little warning, associated with intense rainfall or rapid snowmelt.

Subdued Floods

Gradual floods resulting from prolonged rainfall events, allowing for more effective management.

Hard Engineering Solutions

Flood control strategies involving the construction of artificial structures like dams and levees.