Water Resources Flashcards
What are the four main parts of the module?
Surface Hydrology, Groundwater Hydrology, Water Resources, Flood Risk Assessment
True/False
Water Resources Management includes calculating both hydropower and irrigation water demand.
True
Agriculture consumes about ___% of global blue water withdrawals.
70%
What proportion of global food is produced in artificially irrigated areas?
40 %
Concepts – Supply, Demand, Scarcity
Water stress → __
Water scarcity → __
- Demand exceeds supply or poor quality limits use
- Annual supply < 1000 m³ per person
An annual supply < ___ m³/person is water stress
< ___ m³/person is water scarcity.
1700
1000
What is virtual water?
The water used in the production of goods or services
Green water → __
Blue water → __
Grey water → __
Rainwater evaporated
Surface/groundwater evaporated
Polluted water volume
1 cotton shirt = ___ litres of water
4100 L
List three major uses of water in human activities.
Domestic, Irrigation, Industrial (plus Commercial, Mining, Thermoelectric, etc.)
True/False
UK average domestic water use is 210 L/person/day.
False (it’s 140 L/person/day)
Hydropower equation:
P = εₜ εg ρ g h Q
Where P = power, ε = efficiencies, h = head, Q = flow
Runoff Ratio (RR) = __
RR = R̄ / P̄ (average runoff / average precipitation)
Formula
Irrigation requirement:
I = Ep − P + R
Irrigation Water Demand
Ks = 1 →
Et = Ep →
- Optimal growing conditions
- No water stress
Kc depends on:
Crop type → __
Climate → __
Soil → __
- Albedo, height, stomata
- Wind, humidity
- Planting density
Kc values vary by growth stage: Initial, Development, ____, ____
Mid-season, Late-season
True/False
Kc values are fixed across crop life cycle.
False (they vary by stage)
Formla
Total Available Water (TAW):
TAW = (θFC − θWP) × Zr
Field Capacity (FC) = suction of __
Wilting Point (WP) = suction of __
- −0.33 bar
- 15 bar
Formula
RAW =
p × TAW
True/False
Applying water above RAW reduces stress without losses
False (can cause seepage losses)
List two surface irrigation types.
Basin, furrow (others: flood, border-strip, etc.)
Sprinkler irrigation → __
Micro-irrigation → __
- Simulates rainfall
- Drip/trickle systems
True/False
Drip irrigation reduces salinisation risk.
False (it increases salinisation due to evaporation)
Drivers of Hydrological Change
Urbanisation → __
Agriculture → __
Forestry → __
- Increases impermeable surfaces, alters runoff
- Alters crop types, soil moisture, drainage
- Deforestation reduces evapotranspiration, increases runoff
Key human drivers of hydrological change include: urbanisation, agriculture, forestry, and ______.
climate change
True/False
Forests reduce water runoff and stabilise catchment hydrology.
True
What is the principle of natural flood management?
Using natural processes to reduce flood risk, such as restoring wetlands or reforesting catchments.
What is “water sowing and harvesting”?
Traditional methods to store water in landscapes, especially in high-altitude Andean regions.
What are greenhouse gases?
Gases that absorb and re-emit longwave radiation, warming the atmosphere.
True/False
Greenhouse gases block both longwave and shortwave radiation
False (transparent to shortwave, absorb longwave)
Formula
Boltzmann Law:
F = εσT⁴
Where F = radiated energy, T = temperature, ε = emissivity, σ = Boltzmann constant
Formula
Wien’s Law:
λmax = 2897 × 10⁻⁶ / T
Sun temperature →
Earth temperature →
- shortwave radiation
- longwave radiation
What is a model in climate science?
A set of equations simulating real-world systems, used for prediction and scenario analysis
What do GCMs simulate?
The global climate system and hydrological exchanges of energy and water.
True/False
GCMs only simulate atmospheric processes
False (they include ocean, land, hydrology, etc.)
What is CMIP5?
A standardised comparison of climate models used in IPCC reports.
Projecting climate change requires assumptions about ______ scenarios.
socio-economic
True/False
Climate models can reproduce current temperature trends using only natural forcings.
False
Hydrological Processes in GCMs
Evapotranspiration modelled with → __
UK Met Office model → __
- Penman-Monteith
- MOSES land surface model in HadCM3
What is the spatial resolution of the HadCM3 atmospheric model?
~417 km × 278 km (too coarse for most catchments)
To use GCMs locally, projections must be _______.
downscaled
True/False
Downscaling adds certainty to model outputs.
False (it introduces new uncertainties)
Why is there often a mismatch between GCMs and hydrological needs?
Because GCM resolution is too large to capture local hydrological processes.
Name two local hydrological impacts of climate change.
Changes in river flow, shifts in seasonal runoff patterns
True/False
GCMs are accurate enough to directly assess water risks in small catchments
False
