Adapting Water Management to Climate Change

– Some Ideas from California

Jay R. Lund

Department of Civil and Environmental Engineering

University of California - Davis

“You can never step in the same river twice”

Heraclitus

CaliforniaWaterBlog.com

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Main points1. California has a dynamic global society, economy, &

climate – Mostly good, but challenging.

2. Economic structure drives most management change

3. Water management portfolios are central to success – supplies and demands, with others in region

4. Portfolios add flexibility for variability & uncertainty

5. Droughts/crises provide focus to help water adjust management to changing objectives and conditions

6. Technological and institutional adjustments build on existing institutions and infrastructure

7. Adjustments also rebalance portfolio of local, regional, state, and federal roles and innovations

Water and People in California

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18 million people756,000 sq. km.

40 million people404,000 sq. km.

California has lots of droughts

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SOURCE: Western Regional Climate Center.

Most annual rainfall variability in US

SOURCE: Dettinger, et al. 2011. “Atmospheric Rivers, Floods and the Water Resources of California.” Water 3(2), 445-478. .

NOTES: Dots represent the coefficient of variation of total annual precipitation at weather stations for 1951-2008. Larger values

have greater year-to-year variability.

Annual coefficient of variation

Major Climate Changes

1) Sea level rise

2) Warmer temperatures – less snowpack

3) Bigger flood and drought extremes

4) Other changes …

5) Similar overall precipitation for

California?

Other Major Changes?

1) Population and economic growth

2) Less per-capita water use

3) More tree & vine crops, less irrigated area

4) More environmental water demands

5) Other changes …

Must manage for all these changes, and more…

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Each drought hits a different economy

Droughts

• Paleo-droughts

• 1800s

• 1924

• 1928-32

• 1976-77

• 1988-92

• 2007-09

• 2012-16

Economy

• Pre-European

• Range cattle

• Early farming

• More farming

• Farms + cities

• Farms, cities, environment

California’s economy less agricultural – more robust to drought

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Droughts and change in California 1

Drought Impacts Innovations

1800s Herds & crops

devastated

Local irrigation, 1873

fed CV study

1924 crop

devastation

Local res. projects,

Major water project

plans – regional/state

1928-32 Delta salinity,

crop losses

Major dam & canal

project plans –

statewide scale

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Droughts and change in California 2

Drought Impacts Innovations

1976-77 Big brief urban & ag.

shortages

Urban cons.;

early markets

1988-92 Urban & ag. shortages

Endangered fish

Interties, conj.

use; markets,

cons., regions

2007-09 Agric. & fish supplies More use data;

Delta, urb.cons.

2012-16 Warm drought, little

Delta water, big agric.

shortages, fish, forests

Groundwater,

Delta barrier,

more reporting

Actions

Local, private

Local, public + private - diversions

Regional, statewide- dams, canals

Local urban conservation, trades

Interties, conj. use, water markets, new storage – regional, local

More data, Delta institutions

Groundwater – local region w/ state; urban cons. Mandates; fires?

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Swinging Portfolio Development: Institutions and Technology

Droughts

• 1800s

• 1924

• 1928-32

• 1976-77

• 1988-92

• 2007-09

• 2012-16

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2012-2016 DroughtFrequency – warm drought!

Soil moisture – 1 in 1,200 year event?

Snowpack – 1 in 500 year event

Water availability – 1 in 15-40 year event

Damages

Imperceptible statewide urban damage

2-3% loss of agricultural revenues

Forests much affected; fish stocks depleted

Droughts help us make needed changes!

System Integration

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• California’s water system is more than just storage and conveyance

• Portfolio management is successful, but takes time and organized effort.

• Extensive, diverse, variable, & network encourages portfoliomanagement – “much of the above”

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What is Portfolio Management?1. Integrated use of a diverse range of actions:

• Supplies (surface water, groundwater, reuse)• Demands (various)• Institutions (local, regional, state, federal)

2. Lower costs, more adaptable, better multi-benefit performance

3. Adjust with time, conditions, technology, and problems

4. Integration needs more analytical and management effort

5. Adjustments rebalance local, regional, state, and federal actions over time – adaptive management

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Portfolio ElementsMultiple-barriers Infrastructure Multiple Accountability

1. Banned/regulated chemicals and

activities

Local water utility, elected

boards

2. Source protection: Rivers, lakes,

reservoirs, groundwaterPublic health agencies

3. Drinking water treatment State regulators

4. Distribution system Federal regulators

5. Public health system Professional societies

Universities, NGOs, media

Multiple barrier portfolios for waterborne diseases

What would portfolios look like for ecosystem management?

Managing portfolios across sectors?

Portfolio are Local, Regional, & StatewideLocal Activities:- Conservation and use efficiency- Wastewater reuse- Desalination (brackish & ocean)- Groundwater use and recharge- Surface reservoir operations- Water markets and exchanges

Statewide Activities:- Inter-regional water conveyance- Surface reservoir operations- Plumbing codes & conservation incentives- Groundwater banking and recharge- Water market support and conveyance - Wastewater reuse subsidies

Integrating mix of actions and agreements = portfolio planning 17

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San Diego water supply portfolio588 taf/yr578 taf/yr

477 taf/yr694 taf/yr

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Agricultural water supply portfolio –Tulare Basin, California

0%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

0 2000 4000 6000 8000 10000Cumulative Irrigated Crop Area (1,000 Acres)

Cumulative Jobs and Revenues

Cumulative Jobs

Vegetab

les,

Vin

es

Sub

trop

ical Fruits

Alm

on

ds an

d P

istachio

s

Decid

uo

us

(Orch

ards)

Pro

cessing

Tom

ato

Other Field, Grain, and Feed Crops

Fresh To

mato

+ Cu

curb

its

On

ion

+ Garlic

Josue Medellin

2015 Estimated Agricultural Drought Impacts

Description Impact Base year Percent

Drought water shortage (million acre-ft) 8.7 26.4 33%

Groundwater replacement (million acre-ft) 6.0 8.4 72%

Net water shortage (million acre-ft) 2.7 26.4 10%

Drought-related idle land (acres) 540,000 9 million* 6%

Crop revenue losses ($) $900 million $40 billion 2.3%

Dairy and livestock revenue losses ($) $350 million $13 billion 2.7%

Costs of additional pumping ($) $590 million $780 million 75.5%

Net revenue losses ($) $1.8 billion 54 billion rev. 3.3%

Total economic impact ($) $2.7 billion NA NA

Direct job losses (farm seasonal) 10,100 200,000# 5.1%

Total job losses 21,000 NA NA

* NASA-ARC estimate of normal Central Valley idle land is 1.2 million acres.

# Total agriculture employment is about 412,000, of which 200,000 is farm production.

Analysis and data for integration

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• Integrating complex systems• Complexity of portfolios• Institutional integration• Conflicting institutional missions• Often easier from local level up• Adapt portfolios over time

•Analysis and data helps• Models (integrated, hydro-economic)• Databases• Access, quality control, transparency

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Agricultural water supply portfolio

Pros and Cons of Portfolios

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• Pros• Lower cost mix of actions• Make more friends, more resource access• More adaptable and flexible• Higher reliability

• Cons• Harder to manage• Messier negotiations• Harder to regulate• Need to adapt portfolios over time

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Complexity adds possibilities1) Portfolios central to success for many

water purposes and problems

2) Overall economy is robust to well-managed water. But ecosystems most harmed/least prepared

3) Integration is easier said than done

4) Integration needs organization,

incentives, state framework

5) Better water accounting

6) Change will occur, must

prepare for it

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Some lessons from California

1. Portfolio-based management can be cost-effective and adaptable

2. Portfolios manage supplies, demands, and finance together, regionally.

3. More expensive supplies encourage managing demands and integrated management.

4. Globalization buffers against drought

5. Each drought is different, but all give opportunities

6. Economic structure drives/supports management

7. Climate and other changes will require careful changes to management.

Further Readings Lund et al. (2018) , "Lessons from California's 2012-2016 Drought," JWRPM, Oct. 2018

Hanak et al. (2011) Managing California’s Water, PPIC.org

Hundley (1992), The Great Thirst, UC Press.

Kelley (1989), Battling the Inland Sea, UC Press.

Lund et al. (2010) Comparing Futures for the Sacramento San Joaquin Delta, UC Press

Pinter, et al. (in press), “The California water model: Resilience through failure,” Hydrologic Processes.

Pisani (1983), From Family Farms to Agribusiness, UC Press

Mavensnotebook.com

CaliforniaWaterBlog.com