Adam Hutchinson, P.G., CH.G.

Recharge Planning Manager

Orange County Water District

ASCE Panel Discussion

July 23, 2015

Water in the OC?

Can you say, “Recycled”?

The Orange County Water District was formed by the State

in 1933 to protect and manage Orange County’s

groundwater supplies.

First Board of Directors

• Declining flow of Santa Ana River

• Basin overdraft

• Seawater intrusion

• Attempts by LA County to obtain water rights in Orange County

Why?

OCWD encompasses 370 square miles in the

lower watershed of the Santa Ana River.

Orange County

groundwater basin

provides water for over

2.4 million people

Semi-arid region: 14

inches/year

Basin storage provides insurance during times

of drought.

-700,000

-600,000

-500,000

-400,000

-300,000

-200,000

-100,000

0

19

69

19

71

19

72

19

74

19

75

19

77

19

78

19

80

19

82

19

83

19

85

19

86

19

88

19

90

19

91

19

93

19

94

19

96

19

97

19

99

20

01

20

02

20

04

20

05

20

07

20

09

20

10

20

12

20

13

20

15

Acre

-fe

et

Belo

w F

ull

Full

Dry periods

Basin Operating Range

Pumping

reduced due

low storage

level

Water Factory 21 was

replaced in 2008 with the

Groundwater

Replenishment System

(GWRS)*.

Ultraviolet Light (UV) with

Hydrogen Peroxide

Brine to

Ocean Outfall Backwash

returns to sewage treatment plant

Microfiltration

(MF)

Reverse

Osmosis

(RO)

Seawater

Barrier

Secondary

Effluent

Normally

Goes to

Ocean Recharge

Basins in

Anaheim *70 MGD

2015: 100 MGD

Future: 130 MGD

Recycled water from the upper watershed has

been an important source for many years.

962,403 19%

2,304,241 47%

1,451,865 29%

225,661 5%

Total Recharge in Surface System Over Last 30 yrs (af)

Imported

Santa Ana River (Non-Wastewater Origin*)

Santa Ana River(Wastewater Origin*)

Recycled (GWRS)

*Estimated

(Baseflow and Stormflow)

A diverse portfolio has been created to

meet water demands.

Santa Ana River 64,000

14% Storm flow 50,000

11%

Natural Recharge

60,000 14% GWRS

103,000 23%

Misc. 18,000

4%

Imported Water 150,000

34%

Total Water Demands 445,000 afy

A diverse portfolio has been created to

meet water demands.

Santa Ana River 64,000

14% Storm flow 50,000

11%

Natural Recharge

60,000 14% GWRS

103,000 23%

Misc. 18,000

4%

Imported Water 94,000 21%

Ocean Desalination

56,000 13%

Total Water Demands 445,000 afy

Current Initiatives

• GWRS Final Expansion (130 mgd)

• Increased Storm Water Capture at Prado

Dam

• Evaluation of Desalination Option

Questions? Questions?

Contact Info:

Adam Hutchinson

Recharge Planning Manager

ahutchinson@ocwd.com

Recharge water sources have played different

roles at different times.

0

50,000

100,000

150,000

200,000

250,000

300,000

19

36

19

40

19

44

19

48

19

52

19

56

19

60

19

64

19

68

19

72

19

76

19

80

19

84

19

88

1992 *

1996 *

2000 *

2004*

2008*

2012*

An

nu

al

Rec

harg

e (

afy

)

Year (1936-1990 is Oct-Sept water year, 1991-2014 is July-June Fiscal Year)

GWRS

Imported Water

Storm Flow Recharge

Recharged Base Flow

Base/Storm Flow

Sources

“Maximize Capture”

Imported Source

“Fight Seawater”

GWRS Source

“Increase

Supplies”

With GWRS, recycled water is now a critical

component of recharge to the basin.

84,572 af

Total FY12-13 Recharge: 238,646 af

Recycled Water

31%

Santa Ana River Base Flow

35%

Imported Water

17%

Natural Recharge

8%

Storm Flow

8%

73,486 af

19,698 af

41,004 af 19,886 af

Demand for groundwater has more than

doubled in last 60 years.

0

50

100

150

200

250

300

350

400

1950

1955

1960

1965

1970

1975

1980

1985

1990

1995

2000

2005

2010

Acre

-fe

et

per

Year

(x 1

,000)

Groundwater Production

Basin storage must be managed within limits or

risk adverse impacts.

- 500,000

0

- 100,000

Acre-Feet

66,000 AF Conjunctive Use Storage

FULL

- 150,000 “Neutral” Zone (Target Range)

Allows for 2-4 consecutive dry years, including

withdrawal of Conjunctive Use Storage

Available storage for one wet year

Short-term Emergency Storage - 700,000

Negative

Impacts

Shallow

groundwater

Subsidence

Sea water

intrusion

Reduced

Pumping

Capacity

OCWD has basin management triggers tied to

basin storage conditions.

Basin Storage

Conditions (acre-feet below full)

Basin Management Actions to

Consider

Less than 100,000 af Raise BPP

100,000 to 300,000 af Maintain and/or raise BPP

300,000 to 350,000 af Seek additional supplies to refill the

basin and/or lower the BPP

Greater than 350,000 af Seek additional supplies to refill the

basin and lower the BPP

The BPP has ranged from 62 to 89 percent and

may be lowered in 2015-16.

70% 70%

89%

80%

70%

65%

62%

70%

65%

70% 70% 70% 70% 70%

74%

80%

75% 75% 75% 75% 75% 75%

66%

64%

69%

80%

69%

62% 62%

65%

68% 70%

72%

40%

50%

60%

70%

80%

90%

100%

1970

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

1994

1996

1998

2000

2002

2004

2006

2008

2010

2012

2014

Fiscal Year Ending

Basin Production Percentage

High imported water costs makes local

resources development attractive.

$0

$200

$400

$600

$800

$1,000

$1,200

1936

1941

1946

1951

1956

1961

1966

1971

1976

1981

1986

1991

1996

2001

2006

2011

Co

st

per

Acre

Fo

ot

Replenishment Assessment

MWD Treated Water

MWD Replenishment Water (1949-2007)

Natural Recharge $0

Santa Ana River/Storm Flow $20

GWRS $500

Untreated MWD $600

Desalination? $1900

Development of local water resources has

increased the sustainable yield of the basin.

61,000 61,000 61,000

36,500

112,000

36,000

64,000

70,000

43,139 134,000

57,718 65,000

-

100,000

200,000

300,000

400,000

500,000

600,000

Without OCWD 10-Yr Avg (2005-2014)

Future Estimate

Recharge (afy)

Imported Water

Recycled Water

Storm Flow

Santa Ana River Base Flow

Natural Recharge (Rain, subsurface inflow)

Local

Water

Sustainable Yield

w/o OCWD

Total recharge to the basin has been below

average for 6 of the last 10 years.

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

400,000

450,000

500,000

20

04

-05

20

05

-06

20

06

-07

20

07

-08

20

08

-09

20

09

-10

20

10

-11

20

11

-12

20

12

-13

20

13

-14

To

tal

Rech

arg

e (

acre

-feet)

Fiscal Year (July-June)

Natural Recharge

In-lieu Recharge

Injection Recharge

Surface RechargeAvg. 326,000 afy

Recycled water has helped OCWD weather

the current drought.

• Drought has resulted in reduced natural

recharge

• Santa Ana River base flows have declined by

more than 50% in last 9 years

• Basin storage has fallen to 400,000 af below

full

• May need to reduce pumping from basin

• Increased supply of recycled water has

greatly mitigated impact of drought