California

Question 1

What is water stress?

Answer 1

• imbalance between demand and available water
• demand>available amount
• Available amount may be smaller physically or due to quality of water

Question 2

What are the types of drought?

Answer 2

• Meteorological
  
  • low levels of long term rain
  • induced by decrease in evapotranspiration
• Agricultural
• Hydrological
  
  • starts with lack of rain
  • takes some time to affect water flow
• Socio-economic

Question 3

What is the source of the majority of California’s water supply?

Answer 3

• Melting snowpack

Question 4

What has happened to the snowpack?

Answer 4

• decreased in size
• 137%, above average in 2005
• 5% below average in 2015
• 2011 peak was not enough to restore snowpack from decrease during drought
• Snowpack has been at this level for 5 periods of time in last 500 year

Question 5

How has rainfall varied in California?

Answer 5

• S California has been consistently below average rainfall from 2013 to 2016
• N California has varied, usually below average
• 2014 was exception, above average rainfall

Question 6

What does water stress lead to?

Answer 6

• Deterioration of fresh water resources
• quantity wise (aquifer over exploitation, dry rivers
• quality wise (eutrophication, organic matter pollution, saline intrusion)

Question 7

What were the conditions of the drought in California?

Answer 7

• 34% less rainfall in 2013
• 12 consecutive months of drought by 2014
• Some rain in December 2014
• needed 6 times this to recover hydrologically
• Climate variability was determined to have a 8-27% contribution to drought
• Drought means farmers must overextract
• exacerbates agricultural drought

Question 8

What is an agricultural drought?

Answer 8

• When soil moisture is insufficient to meet demands of a particular crop
• due to factors such as precipitation shortages, differences between actual and potential evapotranspiration, soil water deficits, reduced groundwater/reservoir levels
• results in crop failures or greatly reduced yields
• Evident after meteorological droughts but before hydrological droughts

Question 9

What is a socioeconomic drought?

Answer 9

• When water demand for social and economic purposes exceeds water availability
• result of weather related shortfall in water supply or overuse of available resources
• Differs from other droughts as is dependant on temporal and spatial variations in supply and demand

Question 10

What was the meteorological cause of the drought in California?

Answer 10

• ENSO cycle La Niña phase
• resulted in reduces rainfall in California