Post on 16-Aug-2015
transcript
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
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77
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78
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80
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82
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83
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90
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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
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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
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10
-11
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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