Lesson 1 Deffinitions Water EQ1 Flashcards
Drainage Basin
A drainage basin is a subsystem within the
global hydrological cycle.It is an open system with external inputs
and outputs that cause the amount of
water in the basin to vary over time
Tributaries
A tributary is a freshwater stream that feeds into a larger stream, river or other body of water. The larger, or parent, river is called the mainstem
Confluence
a confluence forms when there are two or more bodies of water that join to form a single channel
Watershed
the edge of a drainage basin; highland which divides and separates waters flowing to different rivers.
Open System
A system where water leaves or enters the cycle. There is not a set amount of water as it can vary with inputs and outputs
Water Budget
The water budget is the amount of water within a local hydrological cycle. The water budget can therefore change over time
why does the amount of water in a local hydrological cycle change
Local hydrological cycles have inputs and outputs from other neighbouring cycles. This can lead to a variation in the water budget caused by variations in inputs and outputs.
What is the fundamental reason of why it rains?
All types of precipitation are caused by air that rises. As air rises it cools, and it can therefore not hold as much moisture in the air. The excess moisture is released in the form of precipitation.
What is orographic precipitation?
Produced when hot air is forced upwards as it moves over a mountain range. As the air rises and cools, water vapour in the air condenses and orographic clouds form. Most of the rain falls on the upwind side of the mountain. The lee side of the mountain range has scarce rainfall.
What is frontal precipitation?
Results when the leading edge of a warm, moist air mass (warm front) meets a cold and dry air mass (cold front). The molecules in the cold air are more tightly packed together, so the cold air is denser than the warm air. The lighter air mass is forced upwards over the denser air. As it rises the warm air cools, the water vapour in the air condenses, and clouds and precipitation results.
what is convectional precipitation?
Results from the heating of the earth’s surface. The warm ground heats the air over it. As the air heats up, the air molecules begin to move apart (the air expands). With more distance between molecules, the molecules are less densely packed so the air becomes “lighter” and rises rapidly. As the air rises, it cools. Water molecules in the air condense into clouds and precipitation. This type of rainfall is common in tropical areas, and the UK during summer.
Where can we find orographic rainfall occurring?
orographic rainfall normally occurs along mountain ranges
Where can we find frontal rainfall occurring?
This type of rainfall occurs where air masses from tropical areas meet with air masses from polar areas
Where can we find convectional rainfall occurring
Convectional rainfall is very common in the tropics.
What is interception
Interception refers to all processes that prevent water from immediately reaching the soil. E.g. Vegetation
What is overland flow (also known as direct runoff)
when water accumulates in the soil until the water table reaches or pools onto the surface
What is through flow?
the lateral unsaturated flow of water in the soil zone, typically through a highly permeable geologic unit overlying a less permeable one
What is infiltration?
Infiltration is when the water that precipitates infiltrates into the soil.
What is percolation?
Percolation in soil is simply the movement of water through the soil
What is groundwater flow?
Groundwater flow is the part of streamflow that has infiltrated the ground, entered the phreatic zone, and has been (or is at a particular time) discharged into a stream channel or springs; and seepage water
What is evaporation?
Evaporation is the process of water changing from liquid to water vapour
What is transpiration?
Transpiration is the transfer of water vapour from vegetation to the atmosphere
What is channel flow?
The movement of water within the river channel
