www.tetratech.com

Rice in the Delta – The Potential to Mitigate Subsidence and Enhance

Sustainability

Philip Bachand et al Tetra Tech

530-564-4594 Philip.Bachand@Tetratech.com

March 3, 2014

USDA NIFA Grant (2010 – 2016). Team

• University of California, Berkeley – Dennis Baldocchi (baldocchi@berkeley.edu) . PI - GHGs – Jaclyn Hatala (jhatala@berkeley.edu. GHGs – Sara Knox saraknox@berkeley.edu; GHGs

• University of California, Davis – – William Horwath (wrhorwath@ucdavis.edu). Project Director;

GHG; Soils; Nutrients – Rongzhong Ye (rzye@ucdavis.edu); GHGs, Soils – Bruce Linquist (balinquist@ucdavis.edu). PI. Agronomy; BMPs;

Nutrients – Emilie Kirk (erkirk@ucdavis.edu. Agronomy; BMPs; Nutrients. – Duncan MacEwan (duncan@eraecon.com); Economics – Leslie Butler (ljbutler@ucdavis.edu; PI; Economics – Lucas Cr Silva (lcsilva@ucdavis.edu); GHGs; Soils – Matthew Espe (mespe@ucdavis.edu); Agronomy, BMPs, Nutrients – Tianxia Zhou (txzhou@ucdavis.edu); Economics

• United States Geological Survey – Jacob A Fleck (jafleck@usgs.gov). PI; Hg

• Tetra Tech, Inc. – Bachand, Sandra Sandra.Bachand@tetratech.com; Geotechnical,

Hydrology, water quality, BMPs – Roy, Sujoy (Sujoy.Roy@tetratech.com); Water quality, Hydrology – Stern, Nicole <Nicole.Stern@tetratech.com>; Water quality,

Hydrology

• Stillwater Sciences, Inc. – Amy Merrill

(amy@stillwatersci.com). PI. regional and state scaling, policy

• Wetlands and Water Resources, Inc. – Stuart Siegel

(stuart@swampthing.org). PI. regional and state scaling, policy

• Hydrofocus, Inc. – Steve Deverel

(sdeverel@hydrofocus.com). PI. Hydrology, subsidence

• San Joaquin Cooperative Extension – Michelle Leinfelder-Miles

Ph. D. (mmleinfeldermiles@ucanr.edu). Agronomy, extension

• Delta Science Center – Roni Gehlke

(festfan@comcast.net). Extension. educational outreach

• Background – Transition From Pre-Development to Today’s Delta

• Subsidence and Land uses in the Delta

• Economic Issues

• Growing Rice - Feasibility

• Effects on Levees

• Subsidies and Offsets

Outline

Conveyance and Exports

1873 TODAY

Corn 36%

Alfalfa & Pasture 26%

Grain Crops 11%

Vines 6%

Tree Crops 2%

Tomato & Vege 4%

Rice 1%

Wetlands 1%

Fallow 2% Non-Irr Agric 6% Urban 5%

Average Land Use in Primary Delta 2007-2012 Total Land Area is about 320,000 acres

(Butler and Zhou, 2012)

Source: NASS GIS data 2007-2011 & DWR 2007

7

Island Transitions from Wetlands to Today’s Agriculture

Flooded Marshland

Reclaimed To Early Agriculture

To Current Agriculture

Marsh Plants

Peat

Slough

Groundwater Table

Delta Island Model Before Farming

Carbon Sequestration Accretion

• Water Treatment • Nutrient Sequestration and Removal • Aquatic Habitat

High Groundwater Table

Wetland Slough Interactions

Crops

Peat

Slough

SiphonPump

Oxidized Peat

Groundwater Table

Early Agriculture

Managed Groundwater Table

Compromised Wetland Slough Interactions

Carbon Losses GHG Emissions Subsidence Initiation

Crops

Peat

Slough

SiphonPump

Oxidized Peat

Groundwater

Table

Current Agriculture

• Subsidence and Dropping Island Elevations

• Dropping GW Table • Decreasing Peat Layer

• Increased pressure head • Increased Seepage • Increased Levee Failure

Risks

Increased Pumping Costs

GHG Emissions $

$

$

$

Non-Farmable Area

Economic Issues

Delta Economy

• To the Delta

– Agricultural Economy (DPC, 2012) • $800M direct (DPC, 2012)

• $2.6B Total w/I Delta ($5.4B Total for CA)

– Recreation (DPB, 2012) • $330M

– Fisheries (Goldman, 1998) • $336M expenditures

• Estimated Annual Economy from Agriculture, recreation and fishing: $3.5B Ann

13

Harvey O. Banks Pumping Plant

• 2.5 miles (4 km) southwest of the Clifton Court Forebay

• First pumping plant for the California Aqueduct and the South Bay Aqueduct.

• Initially flows into the Bethany Reservoir.

Map of CVP canal system in the San

Joaquin Valley.

(U.S. Bureau of Reclamation)

CVP aqueducts are in blue while SWP aqueducts are in red.

California Economy

• To California:

– Drinking Water • Provides Drinking Water to 22M Californians

– $3.6B billed by water agencies to households annually

– Irrigation Water to 2.75M acres outside the Delta • Increases land values by about $24B

• San Joaquin Valley – Ag production and processing

–36B annually – Infrastructure

• Highways, electrical grid, gas, etc….

16

Rice Effects on Subsidence –

Agronomic Data – Linquist et al. GHG emissions – Hatala, Baldocchi et al.

Direct Measurements -- Deverel et al.

Subsurface N 40 kg N/ha

Nitrogen Budget: Relating to Subsidence Kirk et al (2013)

Irrigation water 3 kg N/ha

Previous year’s rice straw 3 kg N/ha

Peat mineralization 121 kg N/ha

Field 10 Nitrogen Uptake in 0N plots = 167 kg N/ha Calculations:

121 + 40 kg N/ha (surface and subsurface)

↓

% N use efficiency

**Assuming NUE from all

sources to be equal

↓

kg N/ha mineralized from peat during the growing season

Net Ecosystem Exchange (g-C/m2/d) Hatala et al 2012)

Cumulative CO2 (g-C/m2/d) Hatala et al 2012)

Subsidence in Corn Deverel et al (2013)

0.60

0.75

0.90

1.05

1.20

1.35

1.50

1.65

1.80

-50.0

-40.0

-30.0

-20.0

-10.0

0.0

10.0

20.0

30.0

Dec-08 Jul-09 Jan-10 Aug-10 Feb-11 Sep-11 Apr-12

OW

-20

B t

ran

sd

uc

er

wa

ter

leve

l (m

)

La

nd

su

rfa

ce

ele

va

tio

n (

mm

)

Date

LVDT LSE 1 LVDT LSE 2 lin pot LSE Manual land surface Inelastic subsidence Water level

2.12 years

-24

.7 m

m

Approximate-1.2 cm/y

Accretion in Rice Deverel et al (2013)

0.000

0.500

1.000

1.500

2.000

2.500

-20.00

0.00

20.00

40.00

60.00

80.00

100.00

120.00

140.00

160.00

Wate

r le

vel re

cord

ed b

y tr

anducer

(m)

Ch

an

ge

in

la

nd

su

rfa

ce

ele

va

tio

n (

mm

)

LVDT Manual land surface elevation measurements Water level

Approximate +0.4 cm/y average

Estimating Subsidence Rates in the Delta

Reference Method

mm/yr Ft/50-years

Corn

-12 -2.0 Deverel et al 2013

-22 -3.6 Deverel and Leighton, 2010

Average -2.8

Peatlands

-1.5 to - 2.6 -0.3 Hatala et al 2012

-4.6 -0.8 Deverel and Rojstaczer, 1996

-5 to -20 0.0 Deverel and Leighton, 2010

Average -0.4

Rice

-1 to -1.4 -0.2 Hatala et al 2012 GHG

4 0.7 Deverel et al 2013 Direct Measurement

-3 -0.5 Kirk et al 2013 N budget

Average 0.0

Elevation Change

Is Rice Feasible in the Delta?

• Grower 1: 70 sacs/ac at $18/sac = $1260/ac

• Grower 2 75 sacs/ac at $17/sac = $1275/ac

Estimates From Growers (January 2013)

0.00

5.00

10.00

15.00

20.00

25.00

30.00

Pri

ce o

f R

ice

($

/cw

t.)

Weighted season-average farm price for rough rice, 1993/94 – 2009/10 (Butler et al 2012)

Long grain:

Medium/short grain:

AT $1275/ac then for price of $15/sac need yield of 85 sacs

(Linquist et al, 2012)

27

Very Small Plot Yields, 2012

Grain Yield

at 14%

Grain Moisture

Variety Type lbs/acre

M105 M 8250 ( 1)

S102 S 8060 ( 2)

09Y2141 SWX 7920 ( 3)

M104 M 7630 ( 4)

08Y3126 M 7480 ( 5)

M206 M 7440 ( 6)

06Y575 L 7430 ( 7)

11Y1044 L 7180 ( 8)

CM101 S 6930 ( 9)

09Y2179 S 6720 (10)

CH202 SPQ 6630 (11)

L206 L 6130 (12)

08Y3310 M 5190 (13)

M202 M 4650 (14)

09Y3887 M 3990 (15)

08Y3269 M 3640 (16)

CH201 SPQ 3520 (17)

M205 M 2990 (18)

Summary of Large Plot Variety Trials,

Yield (lb/ac)

Variety 2009 2010 2011 2012

CM-101 9890 a 7580 a 8320 a 7160

S-102 X 6970 a 9310 a 8060

M-104 6440 c 6490 a 9200 a 8040

M-206 7450 b 4467 b 8380 a 6960

M-202 3870 d X X X

• Twitchell Island – rice subsidy (yield-based) •$0.50 - $10 per cwt

Alfalfa Corn Other Deciduous Pasture Rice •2,500

•2,000 •1,906

•500

•0

$12.78 $13.28 $14.78 $17.28 $22.28

$0.50 $1.00 $2.50 $5.00 $10.00

•Total Rice Price ($/cwt) and

•Subsidy ($/cwt)

•Acre

s

•1,500

•1,000

•2 5 •39 •101

•4 3 3

MacEwan 2013

Possible Solutions Placing rice on islands to decrease levee failure risk along the through Delta conveyance corridor to: 1. Counter hydraulic head on

levee interior (10+ ft below MSL)

2. Counter under- seepage in areas with thin peat (<4ft thick)

Buffer width for safeguarding

corridor

ALL 10+ ft below MSL

10+ ft below MSL AND Peat <

4'

1 Island Buffer 59,411 21,979

2 Island Buffer 13,983 7,357

Total 73,394 29,337

Possible Solutions for increased Water Conveyance security

(A. Merrill et al., 2012)

Water Resources Risk Reduction: Levees Hypotheses: Rice Maintains Elevations

Soil Resistance Forces

Static Forces

Force Balance Enables Levees to Hold Back River

Further Subsidence Reduces Resistive Forces

Rice

Rice maintains elevations and forces

Hydraulic Forces

• Increasing local/farm costs with water pumping, levee maintenance, reduced acreage

• Increasing regional costs with water quality, decreased habitat value/ecological services, GHG emissions, and flood risks

• Increased state costs/risks associated with water conveyance, ecological services, habitat degradation, GHG emission

Subsidence and Delta Sustainability

Future Opportunities with Rice and Wetlands

With Rice (Now)

Current Agriculture

With Rice (One Future Scenario)

Crops

Peat

Slough

SiphonPump

Oxidized Peat

Groundwater

Table

Current Agriculture

• Subsidence and Dropping Island Elevations

• Dropping GW Table • Decreasing Peat Layer

• Increased pressure head • Increased Seepage • Increased Levee Failure

Risks

Increased Pumping Costs

GHG Emissions $

$

$

$

Non-Farmable Area

RiceCrop

Peat

Slough

SiphonPump

Oxidized

Peat

Reducing

Peat

Ground-

water

Table

Implementing Rice on a Delta Island (Now)

• Raise GW elevation • Stop (reverse) subsidence

Change GHG signature From rice

Rice

Crop

Peat

Slough

SiphonPump

Oxidized

Peat

Reduced

Peat

Ground-

water

Table

Implementing Rice (One future scenario)

• Stabilize GW elevation • Stabilize or reverse subsidence • Stabilize levee risks adjacent to rice • Stabilize Seepage

Decrease Carbon Emissions

Local, Regional and State Values Subsidy Opportunities

Local Regional State

GHG Emissions x

Water Resources Risks and Levees x x x

Water Quality x x

Agronomic Sustainability x x

Carbon Sequestration x x

Potential Source for Subsidies From Local, Regional and State Sources

• Delta is highly subsided in many areas – Increasing agricultural and island maintenance costs – Huge ramifications on California economy and will continue to do so

• Rice data supports the contention that rice will stop subsidence

• Other impacts (water quality, GHG emissions, etc… are being considered

– Are being quantified and related to economics – Are looking at management solutions

• Growing Rice –

– Variety data suggests reasonable yields – Are looking at BMPs for fertilizer applications – May need subsidies for widespread adoption in the Delta

• Effects on Levees

– Expect effects on Levees and potential source of local thru state subsidies

• Subsidies and Offsets

– GHG emissions – C – sequestration – Water management opportunities and source reduction

Conclusion

• We need more economic data on growing rice for Delta growers

– Long(ish)-term records if possible

– Cultural practices

– Yields

– Etc….

• Contact Bees Butler or Michelle Leinfelder-Miles

– 530 752 3681

– butler@primal.ucdavis.edu

Requests for Economic Data

Questions?

Notes

Hypotheses

• Subsidence and Water Resources Risks – – Stop or reverse

subsidence

– Can be implemented to stabilize levees from future subsidence

– Can save levee maintenance and repair costs

– May reduce island pumping costs

• GHG Emissions and Carbon Sequestration – – Sequesters carbon

relative to BAU

– Will have lower CO2 Equivalent than BAU

Hypotheses

• Water Quality

– Management can control water quality impacts from rice fields

Watershed of the Sacramento-San

Joaquin Delta and Regions that Use

Delta Water

100 Years of Farming and Water Management has resulted in the “Deep”

Delta

(USGS, Bachand & Associates, UCD)

• Subsidence in Central Delta up to 20 feet or more

• Incurred Costs

– Environmental and Ecological

– Engineering and Infrastructure

– Water Supply and Security

Existing Through-Delta Water Conveyance:

Through-Delta Flows are part of “Dual Conveyance” plans and draws fresh water through deeply subsided Delta to state and federal project pumps. One and two island ‘buffers’ are approximated areas that could safeguard flowpath from drawing saline waters towards pumps in event of one to multiple island levee failure.

(A. Merrill et al., 2012)

Threats to Water Conveyance: Increased hydraulic head

Levee Failure Large difference in elevation between surrounding water and internal island creates high (inward) hydrostatic pressure along island boundaries (levees). Threshold set at 10 feet below MSL (pink)

(A. Merrill et al., 2012)

Threats to Water Conveyance: Reduced peat thickness

Under-Seepage Below -10 ft MSL AND Low Peat Thickness (< 4t) Higher saturated conductivity of mineral soils under peat increases rate of under-seepage. ~ 4 ft or more of peat suppresses under-seepage (approximate threshold from S. Deverel pers. comm. 2012) (A. Merrill et al., 2012)

Nitrogen Cycling and Rice: Implications for Subsidence of Delta Peat Soils

Twitchell Island, 2011 – 2012 Emilie Kirk

Dr. Bruce Linquist Dr. Chris van Kessel

Funding: USDA Ag and Food Research Initiative

UCD Dept. Plant Sciences GSR

(April 2013)

N Rate Trial Findings (Kirk et al, 2013)

ab

ab

a

b b

a ab

abc bc

c

0

2000

4000

6000

8000

10000

12000

14000

0 40 80 120 160

Gra

in Y

ield

(k

g/h

a)

N Fertilizer Applied (kg N/ha)

Grain Yield Response to Nitrogen Fertilizer

M-104 NxVariety Trial CRRB Data Twitchell 2011 Twitchell 2012

Peat Soils and Mineralized Nitrogen: Does more soil carbon always lead to more

mineralized nitrogen?

Matt Espe

UC Davis – Dept of Plant Sciences

Nov. 12th, 2013