Unit 4 background presentation

1. This work is supported by the National Science Foundation’s
Directorate for Education and Human Resources TUES-1245025, IUSE-
1612248, IUSE-1725347, and IUSE-1914915. Questions, contact education-AT-unavco.org
MEASURING WATER RESOURCES
Unit 4 Water budget assessment
of a California drought

2. OUTLINE
1. CA drought: Spatial extent, timing, and historical perspective
2. California Physiography: Mountains and valley
3. Drought and societal impacts
4. Precipitation record
5. Measuring snow with snow pillows and GPS-IR

3. PALMER DROUGHT SEVERITY INDEX
“The Palmer Drought Severity Index (PDSI),
devised in 1965, was the first drought indicator
to assess moisture status comprehensively. It
uses temperature and precipitation data to
calculate water supply and demand,
incorporates soil moisture, and is considered
most effective for unirrigated cropland”1.
1 https://www.drought.gov/drought/content/products-current-drought-and-monitoring-
drought-indicators/palmer-drought-severity-index.

4. CALIFORNIA DROUGHT: HISTORICAL RECORD

5. CALIFORNIA DROUGHT: SPATIAL EXTENT
March 31, 2015April 1, 2014
U.S. Drought Monitor Intensity: Multiple indicators of drought conditions

6. CALIFORNIA DROUGHT: TIMING
Time series of U.S. Drought Monitor intensity, from
http://cpo.noaa.gov/ClimatePrograms/ModelingAnalysisPredictionsandProjections/MAPPTaskForces/DroughtTaskForce/Californi
aDrought.aspx

7. CALIFORNIA DROUGHT: TIMING
March 2013 March 2015 March 2017

8. CALIFORNIA DROUGHT IMPACTS: SOCIETY
“We are embarked upon an experiment that no one has ever tried,” said Gov. Jerry
Brown in early April, in ordering the first mandatory statewide water rationing for
cities.”
and
“…California, from this drought onward, will be a state transformed…The California
drought of today is mostly nature’s hand, diminishing an Eden created by man. The
Golden State may recover, but it won’t be the same place.
(NY TIMES: http://www.nytimes.com/2015/05/03/opinion/sunday/the-end-of-california.html?_r=0)

9. HUMAN COST OF DROUGHT
USDA personnel talks to farmer about the damage the drought has
caused to a vineyard in the Lamont farming community in
southeastern San Joaquin Valley Feb. 26, 2014.

10. HUMAN COST OF DROUGHT
July 2015 - Grandfather and great-granddaughter stand by the water tank they used for water
after their well went dry. Wells went dry across many communities in California’s southern
Sacramento-San Joaquin Valley as the exceptional drought continued. People became
dependent on water trucks.

11. JUNE 2017 – CALIFORNIA GROUNDWATER STILL
BELOW NORMAL
Although the surface
water had recovered by
spring 2017, the
groundwater remained
very low

12. CALIFORNIA DROUGHT: PHYSIOGRAPHY
See Sacramento-
San Joaquin Valley
Basin Map (pdf)
• Two large
basins:
Sacramento
and San
Joaquin (total
area = 1.55x105
km2)
• Sierra Nevada
Mountains
(granitic rocks)
• Central Valley
(deep
sediments)

13. CENTRAL VALLEY GROUNDWATER: PRE AND POST DEVELOPMENT CROSS-
SECTION FOR CENTRAL PART OF SAN JOAQUIN VALLEY

14. CALIFORNIA DROUGHT IMPACTS: HYDROLOGY
• Surface Water (image
on right)
• Groundwater
• Ecosystems

15. PRECIPITATION: NCDC, CLIMATE DIVISION MONTHLY DATA
Measured at 100’s of locations
Gridded to 5 km
Averaged over “Climate Division”

16. NCDC WATER YEAR PRECIPITATION: SACRAMENTO-SAN
JOAQUIN BASIN

17. “WATER YEAR” VERSUS CALENDAR YEAR
What is a Water Year?
“….defined as the 12-month period October 1, for any given year through September 30, of the
following year.
The water year is designated by the calendar year in which it ends and which includes 9 of the
12 months.
Thus, the year ending September 30, 1999 is called the "1999" water year.”
http://water.usgs.gov/nwc/explain_data.html

18. SNOTEL STATIONS
Snow Water Equivalent (SWE) is the
depth of water that would result if all
the snow was melted.
Pressure from the overlying snow is
measured beneath the pillow.
Information is transmitted to data
centers.

19. GPS REFLECTIONS
Estimate snow height
from frequency of
interference pattern.
P101 (Utah)

20. USING GPS-REFLECTOMETRY FOR TERRESTRIAL HYDROLOGY
STUDIES
Changes in the ground
such as added snow
change the path and
characteristics of the
reflect GPS signal
P101 (Utah)

21. REFLECTED GPS SIGNALS

22. Choosing sites for terrestrial hydrologic variables
P013, Paradise Valley, NVP015, Show Low, AZ
BAD: Buildings, roads, complex
topography, cows
Good: natural ecosystems, undisturb-
ed surface, simple topography

23. GPS SIGNAL STRENGTH DATA
Direct Signal
Reflected Signal

24. GPS REFLECTION FOOTPRINT: ~1000 M2
MEASUREMENT FREQUENCY: DAILY
Meters
Meters
GPS

25. GPS stations
currently
being used
for snow
depth.