Water Flashcards
Define, Hydrosphere
The hydrosphere is made up of large bodies of water, such as: The oceans, lakes, icecaps and rivers that are mobilised by the Sun and gravity. It is also known as the hydrological cycle and it involves water in its three states (liquid, solid and gas).
Define, Hydrology.
Hydrology studies the mobilisation of ground and surface water, including its physical and chemical content.
What are the two main types of water in the hydrological cycle?
- Meteoric: Water derived from atmospheric condensation that, joins the larger body of the hydrosphere as surface and groundwater.
- Saline: The waters of oceans and lakes
What is residence time?
The length of time during which a substance is suspended at a location.
What is interception?
Interception is the percentage of water, that after precipitation, does not reach the ground due to vegetation.
At what tempature does evaporation take place under normal atmospheric pressure?
Evaporation at normal atmospherioc pressure can take place at any temperature.
What increases the rate of evaporation? And what reduces it?
Rising temperature and wind can increase the evaporation of water.
While humidity can decrease it.
What are the inputs of the water balance equation?
Precipitation (P) and groundwater flow (∆G)
What are the outputs of the water balance equation?
evaporation (E), streamflow (Q) and groundwater (∆G)
What drives the water cycle?
The Sun’s energy and the Earth’s gravity.
Define water table.
The water table, can be defined as the level at which the geology of the ground is fully saturated.
What properties affects the hydraulic conductivity of water?
The permeability of the rock will affect any liquid that passes through, be it water or oil.
The properties of the liquid, will also affect it’s hydraulic conductivity. A temperature change from 5c to 30c will double the hydraulic conuctivity of water.
Define permeable and impermeable rocks.
A rock with hydraulic conductivity of 1m per day or more is permeable
A rock with hydaulic conductivity of 10-3m per day is classed as impermeable
What is the difference and relationship between porosity and permeability?
The difference is that porosity, is a measurement of the rocks ability to hold water, while permeability is the measurment of the rocks ability to allow water to pass through.
The relatiomship they have it permeability is fully dependant on porosity.
What is the difference between a rock that is isotropic and a rock that is anisotropic?
Anisotropic rock would mean that the physical properties of the rock differ depending on the direction to which you measure it (i.e a piece of wood that is stronger along the grain than against it)
Isotropic would mean that the rock performs the same no matter which direction you measure it.
What is the basic balance water equation?
inflow = outflow + change in storage
What is quickflow?
Quickflow is the visible reaction to a river from rainfall, whereby it increase in either height and speed, due to an influx of quick throughflow and overland flow.
What is Hewlett’s theory?
Hewlett’s theory build upon Horton’s theory by saying that saturated overland flow, occurs in variable areas, for example, ones that are more likely to be humid with water tables closer to the surface.
What is Horton’s theory?
Horton’s theory depends on the rate of rain fall (light, medium or heavy) and also the level of ground infiltration. Thus is most applicabe to areas of low vegetation, arid areas or culitvated fields.
What is the equation? And what does it mean?
The amount of run off from a catchment or river is a product of its cross-sectional area. Thus the average speed and run off from an area, is calculated by:
Q =Av
A = Width x Depth
v = distance/time
What is meant by “lag time”?
It is the time between maximum precipitation and peak discharge rates.
Name this seldom type of flow.
Laminar
What is an Ion?
An atom or molecule with a net charge due to the loss or gain of an electron.
Explain the meaning of the superscript symbol Ca2+
This is an atom with a particular amount of charge. That amount of charge is denoted by the ’+’ sign and the amount of charge it has is denoted by the ‘2’.
What are ions with a plus sign called?
cations
what are ions with a negative charge called?
anions
What is ionic bonding and what are ionic materials?
ionic bonding is the bond between atoms or molecules with positive and negative charge.
Materials held together with such a bond, are called ionic materials
When is the level of dissolved oxygen in a river likely to be at its highest and its lowest?
Vegetation is a key player in the extraction and circlation of CO2 in the water and atmosphere through photosynthetic processess.
Thus a river with aquatic plants, will have its highest concentrations of dissolved oxygen during a warm summer afternoon. As oxygen is given off by plants via photosynthesis.
What gas is produced in the oxidisation of organic matter?
Carbon Dioxide
What does he presence of Ammonia, indicate?
Ammonia is the break down of animal and plant matter and is harmfull to aquatic life. So a polluting substance.
IF the concentration of nitrates NO3− is higher than 50 mg/l then it can become dangerous for aquatic life.
What is the meaning of Turbidity?
Cloudy or opaque sample
Name some heavy metals, that bioaccumulate. Further more, explain bioaccumulation.
Mercury (Hg), Arsenic (As), Cadmium (Cd) and Lead (Pb)
Bioaccumulation is the build up of heavy metals within an organism which leads to degrading health within animals highest in the food chain.
what does ICP-AES stand for?
inductively coupled plasma-atomic emission spectroscopy.
Describe endocrine disruptor
endocrine disruptor was used as a pesticide before the EU Directive brought in standards for drinking water.
.
What are OCPs?
OCPS are a class of organochlorine pesticides I
dieldrin - an insecticide now banned - mimics hormones, and causes immunodisfunction, parkinsons and other health defects
How many calibration standards should be prepared, before plotting a calibration curve?
An analyst will usually prepare 5 standard calibration samples.
What is a stock solution?
A concentrated solution that gets diluted into progressively lower concentrations for use.
What is the maximum TDS of irrigation water?
3000mg l-1 But varies depending on crops
Are the parameters for this natural water, okay for irrigation?
No, as the sodium content of the water is higher than the combined magnesium and calcium content. This would be bad for soil, as it reducres permeability by making it sticky when wet, and solid when dried.
Name some water treatement processess
- Ion exchange
- Activated Carbon
- Softening
- Reverse Osmosis
What is Ion Exchange?
Ion exchange is used to ‘soften’ water and remove nitrate from it. It is very similar to the domestic water process where water is passed through a bed of special resin particles
What is the process of activated carbon?
Used to get rid of organic substances in the water, which are then absorbed on the surface of the carbon.
What is softening?
It is the removal of calcium or magenisum in water, through ion exchange via chemical intervension or precipitation.
Reverse Osmosis
Osmosis is where a solution passes through a membrane. Pore size of the membrane allows only water molecules to pass through. Osmosis pressure dictates the movement of solution.
Reverse osmosis, is the introduction of artifical pressure, to allow only water molecules to pass through.
Just like a super fine filitration system.
What features of weather have an affect on water evaporation and why??
Humidity, wind, temperaturel.
The humudity is a measure of the atmospheres saturation level. Low humidity means low saturation, allowing more water to evaporate into the atmosphere, than high humidity which means high saturation, allowing less water to evaporate into the atmosphere.
High temperatures encourage the breaking up of water molecule bonds, causing them to enter the evaporation phase.
Wind circulates air around, pushing away saturated air and bringing in unsaturated air. .
What is the equation that describe the latent heat of vaporisation of water?
R = H + G + E
H = heating air above land surfaced
G = heating soil, veg and surface water
E = Latent heat evaporation
What are the main reservoirs in the water cycle?
Oceans, Underground, atmospheric water, in the rivers, ice caps, soil and lakes.
What does the result of the hydraulic conductivity equation tell us?
The result tells us about the permeability of the rock, by calculating the volume of water that will flow through a unit cross-sectional area of rock per unit of time.
Rocks with hydraulic conductivites of 1m a day or more, are regarded as permeable
Rocks with a hydraulic conductivity of 10-3 m per day are usually regarded as impermeable.
