1. Reservoir Operations and Water Supply Planning at Salt River Project
Roosevelt Dam and Lake, AZ
Reservoir Operations and
Water Supply Planning
at Salt River Project
Jon Skindlov
meteorologist /climatologist
Water Resource Operations
Salt River Project,
Phoenix, AZ
DOI project workshop
28 March 2014
University of Arizona, Tucson, AZ

2. VARIABILITY – VULNERABILITY – UNCERTAINTY

3. Salt River Project SRP Agricultural Improvement and
Power District
Salt River Valley Water
Users Association
Established 1937 as a political subdivision of the state of Arizona
32,452 million kWh sold in FY13
969,000 customers in and around the Phoenix metro area
Established 1903
A Federal reclamation project
A private corporation
Delivers almost 1 million acre-feet per year

4. WATER --Reliable Supply --Drought --Flood Roosevelt Dam and Lake
Phoenix
Superstition Mtns.
WATER
Salt River
--Reliable Supply
--Drought
--Flood
Roosevelt Dam
and Lake
Looking west,
late winter 2008

5. Colorado River Storage Capacity
Lake Powell
24.4 maf
Total System
(Upper and Lower
Colorado)
59.2 maf
Lake Mead
26.3 maf
SRP lakes
2.3 maf 5

6. Salt/Verde watershed area (13,000 sq mi)
Las Vegas
Salt/Verde watershed area (13,000 sq mi)
SRP…
Manages 4 reservoirs on the Salt River, 2 on the Verde River and 1 on East Clear Creek;
Operates approximately 260 groundwater wells;
Delivers nearly 1 million acre-feet of water per year to the 250,000 acre SRVWUA service area.
Mogollon Rim
Salt River
CAP

7. Salt/Verde watershed area (13,000 sq mi)
CAP
CAP canal
“metro area”
SRVWUA area
(375 sq mi: 250,000 acres)
40 miles

8. Salt River Project Reservoir System
Roosevelt Dam
C.C. Cragin Dam
2218’ Top of Safety of Dams
East Clear Creek Storage:
15,000 AF
2151’ Top of Conservation
6720’
6720’ -
Horseshoe
Dam
C.C. Cragin 15,000 AF
2100’ -
Roosevelt Lake
1,653,043 AF
Horse Mesa Dam
2026’
Horseshoe
109,217 AF
- 2000’
1914’
Bartlett
Dam
1891’ -
Apache Lake
245,138 AF
1798’
Mormon Flat
Dam
Bartlett
178,186 AF
- 1748’
Stewart
Mountain
Dam
1660.5’
1610.5’ -
Verde River Storage:
287,403 AF
1529’
Canyon Lake
57,852 AF
1506’ -
VERDE CONSERVATION
STORAGE:
302,403 AF
Saguaro Lake
69,765 AF
SALT CONSERVATION STORAGE:
2,025,798 AF
Total Conservation Storage: 2,328,201 AF
01/09/07 REF/SVRSCIAF-8

9. WINTER (build supply):
WINTER (build supply):
Precip. (Dec-Mar): 6.3 in
Runoff (Dec-May): 665 Kaf
SUMMER (meet demand):
Precip. (Jul-Sep): 6.8 in
Runoff (Jul-Sep): 120 Kaf 9

10. Longer Period Of Sustained Drought
Salt River Project Historic Drought Periods
(Average Runoff 1913–2010 = 1,198,536 AF) 10 20 30 40 50 60 70 80 90
100
Longer Period Of Sustained Drought
7 Years %
4 Years %
19+ Years 1995 – 2014? ??%
5 Years %
% Average
7 Years %
1890
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
2010
Year

11. DRY WET DRY WET DRY 1892-1904: 2 wet, 11 dry 1905-45: 28 wet, 13 dry:
5 wet,
14 dry :
19 wet,
12 dry :
4 wet,
14 dry

12. What is Normal? 15 years above 1,000,000 acre-feet
11 years below 500,000 acre-feet

13. Creating Dependability from Variability
From total demand:
785 to 910 kaf
Demand and constraints on operations due to regulations, urbanization, diminished GW pumping
Impacts dependability we have on supply. Mention that wet years in the midst of a drought are not uncommon

14. Water Resources Planning Will Change

15. Change in Agricultural Water Use
1955
1975
PHX
PHX
Pop. 0.5 M
Pop. 1.3 M
1990
2008
PHX
PHX
Pop. 2.1 M
Pop. 4.0 M
Salt River Water Users Association area

16. Urbanization of Member Lands
SRP expects to be “fully urbanized” by 2017

18. P G S
PHX T M G C

19. Primary water sources for Valley cities: SRP (surface and ground)
[demand: 300 – 340 kaf]
Primary water sources for Valley cities:
SRP (surface and ground)
CAP (surface)
City wells (ground)

20. KNOWNS and UNKNOWNS

21. Longer Period Of Sustained Drought
Salt River Project Historic Drought Periods
(Average Runoff 1913–2010 = 1,198,536 AF) 10 20 30 40 50 60 70 80 90
100
Longer Period Of Sustained Drought
“Drought of Record”
7 Years %
4 Years %
19+ Years 1995 – 2014? ??%
5 Years %
% Average
7 Years %
1890
1900
1910
1920
1930
1940
1950
1960
1970
1980
1990
2000
2010
Year

22. Storage Planning Diagram

23. Storage Planning Diagram

24.
Questions?

27. Journal of Hydrology 509 (2014) 454–473

29. Upper Colorado River Basin
Salt-Verde-Tonto River Basin

30. Demand
Demand is the water that is called for at a predetermined time to be delivered to shareholder or contract customer land, water treatment plants, or power plants.
Today, demand is difficult to predict:
Water use efficiency
Increasing densification
Extended drought
Agriculture to urban
Economic downturn
From total demand ranged from 785 KAF to 910 KAF.

31. Demand Demand is difficult to predict: Water use efficiency
Increasing densification
Extended drought
Agriculture to urban
Economic downturn