week 2 Flashcards
what % of water is saline?
97.5%
where is locked the 69% of the 2,5 % remaining water (eau douce)?
in glaciers or icebergs
on what depend hydrological conditions of a given region?
Global location
and Position in relation to local water reserves
faites une mappe mentale et énumérez les étapes du cycle hydrologique
In what cases is water used for irrigation recuperated within the
cycle (2)
1.Irrigation water often captured and reused on-site or elsewhere in the
hydrologic system
2.Water percolated through soil or as moves as runoff to ground or surface
water
In what cases is water used for irrigation lost from the cycle?
- Reduced quality (e.g., becomes contaminated)
- Water is physically removed
what is water scarcity?
A condition where water demand exceeds
available water supply
water carcity relates water availability to demand , does it implies that dry areas are necessarily scarce?
no!
to what relates water sacrcity? (3)
amount, timing, quality
of water
les régions avec les mêmes quantités de pluies sont elles vulnérables à la “scarcity” au même niveau?
non
scarcity can be affected by many additional factors: (5) Nommez en au moins 3
- consumption rates, demand
- Water reservoirs
3.Access to water (infrastructure, transport, politics, etc.)
4.Pollution
5.Farming practices/education
what is the difference beteween physical water scarcity and economic water scarcity?
Physical scarcity: quand il n’y a pas assez d’eau ppur rencontrer la demande (ex. pas ssez de précipitation ou reservoirs vides
économique: quand il y a de l’eau mais que le manque moyens ou ressources limite son accès (infrastructures, capital humain ou financier, distribution favorisant un groupe plutot qu,un autre,..)
difference between water scarcity and drought
Drought = A period of unusually persistent dry weather that persists
long enough to cause serious problems such as crop damage
and/or water supply shortages
(relates to degree of moisture deficiency, duration and size of affected area)
qu’elles sont les 4 types de sécheresse? truc: SHAM
- Meteorological drought → lack of precipitation for a period of time
- Agricultural drought → period with declining soil moisture [potentially]
resulting in crop failure - Hydrological drought → occurs when surface and subsurface water
supplies are below normal - Socioeconomic drought → failure of water resource system to meet
water demand; when physical water shortages begin to affect people
qui est le plus vulnérable à la rareté de l’eau?
-les régions arides avec une grande variété hydrologique
-Least developped régions (ou pays plus pauvres)
what is transpiration
movement of water from soil to roots , up through plant tissues and out through leaf into atmosphere (voir dessin)
what is used to categorize climate conditions for agricultue, based on water availability
climatic aridity index
what is the principal factor to plant development and crop yield?
water availability
what are the 3 main roles of water in plants? (TCT) aller voir chaque
- trasport, 2.chemical reactions, 3. turgor pressure
stems and leaves sag or fold is a sign :
bad transport of water, reduction in turgor pressure, chemical reaction
turgor press.
what is evaportion?
rate that liquid turns into gas
Is the evapotranspiration difficult to determine with high degree of accuracy? why?
yes, varies between stages of plant development and depend on context specific factors like weather, plant type, soil or management
challenges we face supplying adequate water for agriculture?
- population growth
shifting diets
climate change(wetting-drying issues)
increasing pressure for domestic and industrial uses that limits water for agr
climate change and water
-temp++
-climate change will affect hydrological cycle+overall water supply
-timing, distribution.. (year to year variability, extreme events, wtting and drying trends,..)
-se level rise
-
