Jon Skindlovmeteorologist /climatologistWater Resource Operations Salt River Project, Phoenix, AZ

Roosevelt Dam and Lake, AZ

Reservoir Operations andWater Supply Planning at Salt River Project

DOI project workshop28 March 2014University of Arizona, Tucson, AZ

VARIABILITY – VULNERABILITY – UNCERTAINTY

Salt River ProjectSalt River Project

• Established 1903• A Federal reclamation

project• A private corporation• Delivers almost 1 million

acre-feet per year

• 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

Salt River Valley Water Users Association

SRP Agricultural Improvement and Power District

Roosevelt Damand Lake

Salt River

Superstition Mtns.

Phoenix

Looking west, late winter 2008

WATER--Reliable Supply--Drought--Flood

Colorado River Storage Capacity

Lake Mead26.3 maf

SRP lakes2.3 maf

Lake Powell24.4 maf

Total System(Upper and Lower

Colorado)

59.2 maf

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

Las Vegas

CAP

Salt/Verde watershed area (13,000 sq mi)

“metro area”

CAP

CAP canal

40 milesSRVWUA area

(375 sq mi: 250,000 acres)

Salt/Verde watershed area (13,000 sq mi)

VERDE CONSERVATIONSTORAGE:302,403 AF

SALT CONSERVATION STORAGE:

2,025,798 AF

2026’

1798’

1529’

1914’

HorseshoeDam

StewartMountain

Dam

RooseveltDam

BartlettDam

Mormon Flat Dam

Horse Mesa Dam

Total Conservation Storage: 2,328,201 AF

Horseshoe109,217 AF

Bartlett178,186 AF

Saguaro Lake69,765 AF

Canyon Lake57,852 AF

Apache Lake245,138 AF

Roosevelt Lake1,653,043 AF

1660.5’

2218’ Top of Safety of Dams

2151’ Top of Conservation

01/09/07 REF/SVRSCIAF-8

C.C. CraginDam

6720’

C.C. Cragin15,000 AF

East Clear Creek Storage:15,000 AF

Verde River Storage:

287,403 AF

2100’ -

6720’ -

- 2000’

1506’ -

1610.5’ -

- 1748’

1891’ -

Salt River Project Reservoir System

Salt-Verde Watershed Normals

0

50

100

150

200

250

300

Infl

ow

, Ka

f

0

1

2

3

Pre

cip

ita

tio

n, i

nc

he

s

Inflow (median) Precipitation (average)

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

1971-2000

1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

10

20

30

40

50

60

70

80

90

100

% A

vera

ge

Year

7 Years1898 - 1904

35%

7 Years1942 - 1948

62%

5 Years1953 - 1957

47%

4 Years1974 - 1977

52%19+ Years

1995 – 2014???%

Salt River Project Historic Drought Periods(Average Runoff 1913–2010 = 1,198,536 AF)

Longer Period Of Sustained Drought

DRY DRY DRYWET WET

1892-1904: 2 wet, 11 dry

1905-45: 28 wet, 13 dry

1946-64: 5 wet, 14 dry

1965-95: 19 wet, 12 dry

1996-2013: 4 wet, 14 dry

What is Normal?

1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 310

5

10

15

20

25

30

35

40

45

50

Water Year Volume

31-year median (1982-2012)

Lowest to Highest

Wat

er Y

ear V

olum

e (1

00,0

00 a

cre-

feet

)

Median = 775,000 acre-feet

11 years below 500,000 acre-feet

15 years above 1,000,000 acre-feet

Creating Dependability from Variability

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 210

500,000

1,000,000

1,500,000

2,000,000

2,500,000

3,000,000

3,500,000

4,000,000

4,500,000

Salt + Tonto + Verde Inflow Total DeliveriesYear

Volu

me

(Acr

e-Fe

et)

From 2001-2010 total demand: 785 to 910 kaf

Water Resources Planning Will Change

Change in Agricultural Water Use

1955 1975

1990 2008

PHX

PHX

PHX

PHX

Salt River Water Users Association area

Pop. 0.5 M Pop. 1.3 M

Pop. 2.1 M Pop. 4.0 M

0

50,000

100,000

150,000

200,000

250,000

1957 1961 1965 1969 1973 1977 1981 1985 1989 1993 1997 2001 2005

Year

Acr

ea

ge

Agricultural Urban

Urbanization of Member Lands

SRP expects to be “fully urbanized” by 2017

http://phoenix.gov/waterservices/wrc/yourwater/wrplan.html

PHXT M

C

SG

P

G

http://phoenix.gov/waterservices/wrc/yourwater/wrplan.html

Primary water sources for Valley cities:SRP (surface and ground)CAP (surface)City wells (ground)

[demand: 300 – 340 kaf]

KNOWNS and UNKNOWNS

1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 20100

10

20

30

40

50

60

70

80

90

100

% A

vera

ge

Year

7 Years1898 - 1904

35%

7 Years1942 - 1948

62%

5 Years1953 - 1957

47%

4 Years1974 - 1977

52%19+ Years

1995 – 2014???%

Salt River Project Historic Drought Periods(Average Runoff 1913–2010 = 1,198,536 AF)

Longer Period Of Sustained Drought

“Drought of Record”

SRP Storage, Pumping & Water Allotment Planning

0

200

400

600

800

1000

1200

1400

1600

1800

2000

1 2 3 4 5 6 7

Year

Res

ervo

ir S

tora

ge

(KA

F)

Gro

un

d W

ater Pro

du

ction

(KA

F)

Median Inflow

Drought of Record

Minimum Pumping

Maximum Pumping

- 75

- 325

- 250

- 200

- 125

3.0 AF/AC

2.5 AF/AC

2.0 AF/AC

Storage Planning Diagram

Storage Planning Diagram

Questions?Questions?

www.srpnet.com Jon.Skindlov@srpnet.com

http://phoenix.gov/waterservices/wrc/yourwater/wrplan.html

Journal of Hydrology 509 (2014) 454–473

http://phoenix.gov/waterservices/wrc/yourwater/wrplan.html

http://phoenix.gov/webcms/groups/internet/@inter/@dept/@wsd/documents/web_content/wsdfaqsupply030714.pdf

Upper Colorado River Basin

Salt-Verde-Tonto River Basin

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 2001-2010 total demand ranged from 785 KAF to 910 KAF.

Demand

Demand is difficult to predict:

• Water use efficiency• Increasing densification• Extended drought• Agriculture to urban• Economic downturn