The Drainage Basin and River Systems

Flashcards covering the drainage basin hydrological system, hydrographs, river landforms, erosion, transportation, deposition, and flood management.

A __________ is the area that is drained by a river and any tributaries.

drainage basin

The boundary of a drainage basin is known as the __________.

watershed

__________ is the change in state of water from liquid to gas, occurring when water is heated by solar energy.

Evaporation

__________ is the process where plants respire through their leaves, releasing water they absorbed through their roots.

Transpiration

The volume of water passing through a cross-sectional point of a river is measured in __________ ($\text{Cumecs}$).

Cubic Metres Per Second

Water that is caught by plants' branches and leaves before reaching the ground is known as __________.

Interception

The storage of water in the pore spaces of rock or lower soil is called __________.

Groundwater

__________ occurs when intercepted water stored on plants and trees flows down a stem onto the ground.

Stemflow

Water that flows above the ground as a large sheet is called __________, while small channels are called rills.

sheetflow

The movement of water from above ground into the soil is called __________.

Infiltration

__________ is the process of water flowing from the ground or soil into porous rock or rock fractures.

Percolation

The speed of __________ is dependent on soil type, with clay soils being slower than sandy soils.

throughflow

When there is no precipitation contribution and only groundwater flow contributes to channel flow, the level is called __________.

baseflow

Groundwater accounts for around __________$\%$ of all Earth's freshwater.

$$30$$

Shallow groundwater aquifers can store water for up to __________ years.

$$200$$

Underground water stores formed during wetter climatic periods that may last for $10,000$ years are called __________ aquifers.

fossil

The __________ is the level at which the pore spaces and fractures in the ground become saturated.

water table

Groundwater is __________ by precipitation infiltrating the ground or surface water bodies seeping into stores.

recharged

Storm events are less effective at recharging water stores because the ground quickly reaches its __________ (saturated state).

field capacity

A __________ is a natural outlet where groundwater flows out onto the surface.

spring

A __________ is a graph that shows how river discharge changes over time.

hydrograph

The time between peak rainfall and peak discharge on a storm hydrograph is known as __________.

lag time

The maximum capacity of a river, beyond which it will burst its banks, is called __________.

bankfull discharge

A __________ hydrograph is characterized by a short lag time and high peak discharge.

flashy

The __________ is the total length of all rivers and streams in a basin divided by the total area of that basin.

drainage density

Clay soils have a higher __________ than sandy soils because they have more total space between particles.

porosity

The process of rocks scraping and grinding along the river channel is known as __________ or abrasion.

corrasion

__________ erosion occurs when water dissolves parts of water-soluble rocks like chalk, gypsum, or limestone.

Solution

The erosional process where water forces air into small cracks under pressure is called __________.

cavitation

Larger rocks and pebbles that cannot be carried within the water are rolled along the river bed in a process called __________.

traction

The __________ shows the relationship between material size and the energy needed to transport, erode, or deposit it.

Hjulström Curve

The __________ line on a Hjulström Curve signifies the point at which material no longer has the energy to be transported and is deposited.

settling velocity

The line of fastest flow and maximum velocity within a river is called the __________.

thalweg

__________ flow is a corkscrew or spiral movement of water occurring in meanders.

Helicoidal

A __________ is a steep-sided, narrow valley formed when a waterfall continually retreats upstream over time.

gorge

The small area of land remaining when meander bends get very close is called the __________.

neck

A deposit of fine sediment on the inside of a meander bend is called a __________.

point bar

Alternating patterns of shallow and deeper water in a river channel are referred to as __________ sequences.

riffle-pool

Natural embankments that build up along a river bank due to repeated flooding are called __________.

levees

Landforms called __________ form at the mouth of a river where it meets a lake or ocean and mass deposits sediment.

deltas

A '100 year flood' refers to a flood that has a __________$\%$ chance of occurring in any given year.

$$1$$

The hard engineering process of removing meanders to make water flow faster is called __________.

channel straightening

Pruning the branches of trees on a floodplain to manage afforestation and reduce flood risk is called __________.

pollarding

The removal of water from a body like a river or groundwater store is called __________.

abstraction

When a river is restored to its original state before human alteration, it is called __________.

river restoration