John LindquistUNITED WATER CONSERVATION DISTRICTMarch 07, 2018
“Location, Location, Location!”The ‘Where’ of Managed Artificial
Recharge Can Be Just as Important as‘How Much’ in Achieving Groundwater
Sustainability
THE CRUX OF THE MATTER(ASKING FOR A FRIEND…)
1. If the recharge in my basin equals or exceeds discharge, I’m good, right?
2. If not, what are the options?
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OUTLINE
1. Real-world example of the concepts
2. Getting quantitative with simplified examples
3. A STAR TREK “teachable moment”
4. Potential impacts of shifting recharge locations
5. Back to the real world6. Concluding thoughts
SanFrancisco
Sacramento
Los Angeles
Ventura County
VENTURA COUNTY AND UNITED WCD
Oxnard
Santa Barbara
Palmdale
Los Angeles
Santa Clarita
VENTURACOUNTY
UWCD
Pacific Ocean
Oxnard
Ventura
Camarillo
Freeman Diversion
United WCDSpreading Grounds
PortHueneme
NBVCPt. Mugu
OXNARD COASTAL PLAIN
Pacific Ocean
OXNARD SUB-BASIN
PLEASANT VALLEYBASIN
FOREBAYAREA
MOST RECHARGE FOR THE OXNARD COASTAL PLAIN OCCURS IN THE NORTH
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FreemanDiversion
Infiltration basins
Santa ClaraRiver
Oxnard
Ventura
Camarillo
OXNARD SUB-BASIN
PLEASANT VALLEYBASIN
FOREBAYAREA
Freeman Diversion
United WCDSpreading Grounds
PortHueneme
NBVCPt. Mugu
WHERE DOES THAT RECHARGE GO?
Pacific Ocean
Oxnard
Ventura
Camarillo
PortHueneme
NBVCPt. Mugu
PUMPING ON OXNARD COASTAL PLAIN
EXAMPLE 1 (BASE CASE)—”EXISTING PUMPING”
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River: +2,900
ET: -900
Spreading: +22,000Areal Recharge:
+28,000
Pumping: +50,000
Ocean (constant head = +5 ft msl)
All units in AF/yr
Net Seawater Flux: -1,900
EXAMPLE 2—”REDUCED PUMPING”
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River: +2,300
ET: -1,300
Spreading: +22,000
Areal Recharge: +28,000
Pumping: +45,000 All units in AF/yr
Net Seawater Flux: -5,800
Oxnard
Ventura
Camarillo
Freeman Diversion
PortHueneme
NBVCPt. Mugu
IMPACT OF REDUCING PUMPING BY 10%
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4,000 acres
=31 avg-sizedfarms
= 60,000 tons/yrof produce(enough for170,000 people)
=$91 million/yrdirect income
(~1,500 jobs)Or, bulldoze 3,000 acres of homes and industry?
A TEACHABLE MOMENT
• War on planet Eminiar 7 is conducted by computer simulation
• a model
• The people of the planet feel this is better than facing the real horrors of war
• The model forecasts who would have lived and died in each battle
• Then the government sends those people to “disintegration chambers”
• Captain Kirk destroys the disintegration chambers and suggests alternative ways to handle conflict
Be like Capt. Kirk, not an Eminiarian!12
“A Taste of Armageddon” (Season 1, Feb. 1967)
EXAMPLE 3—”FOCUSED RECHARGE”
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River: +2,900 ET: -800
Old Spreading Basins: 0
Areal Recharge: +28,000
Pumping: +50,000
All units in AF/yr
New Spreading Basins: +14,000
New Injection Wells: +8,000
Net Seawater Flux: -1,900
EXAMPLE 4—”SURFACE-WATER DELIVERIES IN-LIEU OF PUMPING (AND RECHARGE)”
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River: +4,000 ET: 0
Spreading: +2,000
Areal Recharge: +28,000
Pumping: +30,000
All units in AF/yr
Net Seawater Flux: -4,100
BACK TO THE REAL WORLD: OXNARD COASTAL PLAIN
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• Population: ~400,000 people• Military facilities: 3
• Farmland: 35,000 acres• ~500,000 tons/yr produce• ~$1 Billion economic impact
• Current water needs: 139,000 AF/yr• ~99,000 AF/yr from pumping• ~40,000 AF/yr from imports
19TH CENTURY (PRE-DEVELOPMENT)
South North
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20TH AND 21ST CENTURIES
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HYDROSTRATIGRAPHIC MODEL
Model Layer 1, Semi-perched Aquifer
Model Layer 3, Oxnard Aquifer
Model Layer 7, Hueneme Aquifer
Model Layer 13,Grimes Canyon Aquifer
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NUMERICAL MODEL BOUNDARIES
“GSP-LITE” RESULTS FOR PUMPING SCENARIOS(NO NEW WATER-SUPPLY PROJECTS)
Scenario Pumping Rate Changes
Avg. GW Extractions
(AF/yr)
Reduction in Pumping
(%)
Base Case No changes in 1985-2015pumping rates 99,000 0
Reduced Pumping 50% “haircut” in pumping 49,000 50
ShiftedPumping
No pumping in coastal area, 75% reduction in lower-aquifer pumping, 50% increase in upper-
aquifer pumping69,000 30
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CONCLUDING THOUGHTS• The idea that basin inflow = outflow makes for
sustainable yield was always in doubt• Now, under SGMA, it’s totally dead
• In my simplistic examples, sustainable yield can increase or decrease 10% simply by moving recharge around or using it in a different way
• In the (incomplete) Oxnard coastal plain analysis, just moving pumping around can influence yield by 20% or more
• United hasn’t yet evaluated options for moving recharge or changing in-lieu deliveries of surface water—could we get another 10 or 20% increase in the sustainable yield number? Stay tuned! 21
CONTACT INFORMATION:
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John Lindquist, PG, CHGSenior Hydrogeologist
UNITED WATER CONSERVATION DISTRICT106 N 8th Street - Santa Paula, CA 93060
Office: (805) 525-4431 Direct: (805) [email protected] www.unitedwater.org
