The 2019-20 water year has been quite a roller coaster. First it was very dry, then very wet, and now very dry again (especially for Northern California). As drought conditions return to the Golden State it is important for every one to understand that dry years are normal in California and currently the Metropolitan Water District of Southern California has the most water in dry year storage in its 87 year history. In addition, Californians use approximately 20% less water in 2020 than in 2013, this combination of high water supply vs low water usage ensures that Southern California is well prepared for another long drought.

1. Water Supply Conditions
Kevin Hostert, Water Resources Analyst
Municipal Water District of Orange County
February 20th 2020

2. Subject IntroductionOrange County Weather and Water Supply Conditions
Insight to local weather conditions that affect Orange County’s water supply and water demand

3. Santa Ana Precipitation
(Station #121)
0
5
10
15
20
25
30
35
1‐Jul 1‐Aug 1‐Sep 1‐Oct 1‐Nov 1‐Dec 1‐Jan 1‐Feb 1‐Mar 1‐Apr 1‐May 1‐Jun
Rainfall (Inches)
Santa Ana Year by Year Rainfall Comparison
Historical Average Wettest Year (1997‐98) Driest Year (2006‐07)
2017‐18 2018‐19 2019‐20
0.01 0.04 0.19
0.49
1.19
2.17
2.67 2.76
2.09
0.93
0.25
0.060.00 0 0 0.00
2.17
4.45
0.13 0.02
0.0
1.0
2.0
3.0
4.0
5.0
6.0
7.0
July August September October November December January February March April May June
Rainfall (inches)
Average Monthly Precipitation in Orange County, Ca
Santa Ana Civic Center Gage #121
Avg Fiscal Year
2019‐20 Fiscal Year
85% of Local Precipitation occurs
from November to March (10.88 Inches)
58% of Local Precipitation occurs
from January to March (7.52 Inches)
8.06
14.87
3.82
14.57
8.41
29.06
8.51
2.19
9.46 9.88
16.82
21.39
8.27
6.36
4.37
8.83
8.15
20.66
3.66
20.47
6.75
Average Rainfall 12.9
Inches
0
5
10
15
20
25
30
Rainfall (Inches)
Santa Ana Annual Precipitation Statistics (Fiscal Year July‐June)
79% of Normal as
of 2.19.2020

4. Subject IntroductionRegional Weather and Water Supply Conditions
Insight to regional weather conditions that affect California’s water supply

5. 0
10
20
30
40
50
60
70
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
INCHES
Accumulated Precipitation (8-Station Precip Index)
Historical Average Water Year18-19
Northern California Accumulated
Precipitation
17.75 Inches
55% of
Normal
0.26
1.97
10.69
4.81
0.02
0
2
4
6
8
10
12
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
INCHES
Monthly Precipitation (8 Station Precip Index)
Historical Average Monthly Total
WY 2015 = 37.2
WY 2016 = 57.7
WY 2017
(Wettest) 94.9
WY 2018 = 41
WY 2019 = 69.08
Projected with Average
Conditions = 33.07
0
10
20
30
40
50
60
70
80
90
100
Oct Nov Dec Jan Feb Mar Apr May Jun Jul Aug Sep
8 Station Index all Time Month by Month Cumulative
Totals

6. Snow
Water
10 Units
2 Units
20% Liquid Equivalent
Regional Snow Water
Equivalent 12.30.19
Regional Snow Water
Equivalent 2.19.20

7. SWP Table A Allocation
Note: In 2018 SWP Table A = 35% with no water being removed from MWD storage.
10%
10%
15%
30%
45%
60% 60% 60%
20%
20%
45%
60%
60%
85% 85% 85%
15%
15%
15%
20%
20%
30%
35% 35%
10%
10%
15%
35%
70%
70% 70%
75%
10% 10%
15% 15%
Nov. Dec. Jan. Feb. Mar. Apr. May Jun.
SWP TABLE A ALLOCATION
FOR STATE WATER PROJECT CONTRACTORS
Water Year 2016 Water Year 2017 Water Year 2018 Water Year 2019 Water Year 2020

8. Lake Mead
Shortage Trigger = 1,075 ft
Spillway Elevation = 1,221 ft
Surplus Trigger = 1,145 ft
1,030
1,055
1,080
1,105
1,130
1,155
1,180
1,205
1,230
Elevation (Ft)
Lake Mead Levels: Historical and Projected
projection per USBR 24‐Month Study
Historical Projected

9. MWD 2019 Water Storage

10. MWD 2020 Estimated Water Storage
Colorado River
Aqueduct, 0.988
MAF
State Water Project, 0.3
MAF
0.00
0.20
0.40
0.60
0.80
1.00
1.20
1.40
1.60
1.80
2.00
Million Acre‐Feet
Supply (15% SWP) = 1.275 MAF
Demand (15% SWP) = 1.626 MAF
Storage Take =
0.351 MAF

11. MWD 2020 Estimated Water Storage
2.2
1.8
1.1 1.0
1.7
2.4
2.7
2.3
1.2
0.9
1.3
2.5 2.5
3.1
2.8
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
MillionAcre-Feet
End of Calendar Year
MWD Historical Dry Year Storage
Emergency Storage Dry Year Storage Water Supply Shortage

12. MWD 2020 Estimated Water Storage
2.2
1.8
1.1 1.0
1.7
2.4
2.7
2.3
1.2
0.9
1.3
2.5 2.5
3.1
2.8
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
4.50
2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020
MillionAcre-Feet
End of Calendar Year
MWD Historical Dry Year Storage
Emergency Storage Dry Year Storage Water Supply Shortage
SWP Table A = 35%

13. 2020 Vs 2018 Water Year
0
5
10
15
20
25
30
35
Historical Northern California SWE
Average
2020
2018
WY 2018 = 41
Projected with Average
Conditions = 33.07
0
10
20
30
40
50
60
8 Station Index all Time Month by Month
Cumulative Totals

14. February 20, 2020
Return of the Drought??!!!!!!
December 17, 2019
9.54 % of the state is seeing
“Moderate Drought Conditions”

15. Return of the Drought??!!!!!!
Assuming no “March Miracle,”
a significant amount of the
state will see drought conditions
by June 2020.
0
10
20
30
40
50
60
70
80
90
100
Jan‐00 Jan‐01 Jan‐02 Jan‐03 Jan‐04 Jan‐05 Jan‐06 Jan‐07 Jan‐08 Jan‐09 Jan‐10 Jan‐11 Jan‐12 Jan‐13 Jan‐14 Jan‐15 Jan‐16 Jan‐17 Jan‐18 Jan‐19 Jan‐20
Percent of California in Drought
California D0‐D4 D1‐D4 D2‐D4 D3‐D4 D4

16. Good news, we don’t waste H2O
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
‐
100,000
200,000
300,000
400,000
500,000
600,000
700,000
800,000
1969‐70
1970‐71
1971‐72
1972‐73
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2017‐18
2018‐19
2019‐20
O.C. Population (Millions)
O.C. Annual Water Usage (AF)
Fiscal Year
Orange County Annual M & I Water Usage
O.C. Water Demand for the last 4 FY's is the lowest since FY 82‐83

17. Water Supply Conclusions
• Accumulated Precipitation is extremely below the historical average in
Northern California. Northern California Snowpack is well below average.
• Precipitation in Southern California is below average for the 2019‐20 water
year. Below average precipitation occurs about 65% of the time.
• Key State/Federal Reservoirs Levels are hovering at historical averages, but
anticipate a summer draw down given there will be little spring runoff.
• Table A allocation is at 15 %, which is about 0.3 MAF of water to MWD.
• Drought conditions have strengthen this year but are still relative weak
compared to the last drought.
• The Colorado River System is doing better compared to previous years. There
is only a 4% chance of Lake Mead going into shortage at the start of CY 2021.

18. Questions???