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Integrated Modeling of Climate Stress and Resilience in Snow-Fed Arid Lands

Maureen I. McCarthyUniversity of Nevada, RenoDesert Research Institute

International Atmospheric River ConferenceScripps Institute of Oceanography

09 August 2016

SponsorsPartners

Maureen McCarthy (UNR)

Loretta Singletary (UNCE), Kim Rollins (UNR),

Greg Pohll, Justin Huntington, Shey Rajagopal (DRI)

Kelley Sterle, Karen Simpson, Christine Albano (UNR/DRI PhD students)

Michael Dettinger (USGS/Scripps/DRI)

Rich Niswonger, Eric Morway, Murphy Gardner,

Wes Christensen (USGS),

Shane Coors, Linnet Jose (PWRE)

Derek Kauneckis (Ohio University)

The Team

Snow-fed Arid Lands Globally:Over 50% of World Global Population Depends on

Snowpack for Water Supplies

3Water for the Seasons - NSF/WSC Mar16

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Truckee-Carson River System:Case Study for Snow-fed Arid Lands

• Sierra-Nevada Snowpack• Great Basin Desert• Truckee River – Intensely Managed• Carson River – Few Controls• Newlands Project – 1st BOR Project• American Indian Reservations• Terminal Lake• Endangered Fish Species• Urban Communities• Industrial Development• Agriculture• Wetlands and wildlife• Recreation

Where Evapotranspiration Rules

A Bucket Brigade of Models…

Weather Data or Model

Headwaters Models

SW/GW Models (including water mgmt)

People/Infrastructure/ Decisions

Water Availability – ARs vs no ARs

Downtown Reno Jan 1997 Following Snow then Rain-on-Snow AR events

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Truckee River Fall 2015 Following Four Years without major ARs

Scenarios-based climate-

extremes assessment—

A policy-friendly complement

to ensembles

Mike Dettinger, US Geological Survey

Storyline

Weather data

Runoff Models

Impact Assessments

Using Scenarios

E.g., ARkStorm Scenario

1969 Phase

(focused to south)

1986 Phase

(focused to north)

0 120inches

Courtesy, Tim Brown & CANSAC/DRI

• Historically based Drought Scenarios(current drought + 1990s drought, +/- warming)(dust-bowl era drought +/- warming)

• Paleo-informed drought sequences(with & w/o warming)

• Climate-projection extremes(wet & dry)

Drought scenarios iteratively designed & explored with

stakeholders

What respondents told us was the worst:

0

5

10

15

20

25

30

35

40

45

50

2012-15 1987-94 Other 1997 1950s Other

Nu

mb

er

of

Re

spo

nse

sSurvey results:

Drought Flood

2015 Fourth Year of Drought Nevada/California was a Lost Water Year

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Fractions of Normal Precipitation

What made the past

two years so hard?

• Record-breaking temperatures• 25% and then 5% of normal

snowpack

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Temperatures are playing an important

role in today’s drought & will be a defining

characteristic of future droughts…

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A first scenario…

• Recent-drought case

• We heard from surveys that the current drought is about as bad as many folks can picture…

How bad are things today?

How bad could they get in the near term?

How will a drought like this end?

Fractions of Normal Precipitation

A first

scenario…

Recent-history PLUS++

Putting the current drought into a realistic plausible (if somewhat

pessimistic) perspective

Storyline=2012-2015 followed by 1987-1995

Note: 1987 was amoderate El Nino yr

Scenario A – Current TempsScenario B – Increase Temps 2C (mid-century)

How does a climate scenario feed into hydrologic models?

4 km grid

Fernley

Groundwater

MODFLOW

Model Upper Truckee

Watershed

GSFLOW

Model

Upper Carson

Watershed

PRMS Model

Truckee River

Operations

RiverWare

Model

Truckee

Meadows

Groundwater

MODFLOW

Model

Carson Valley and Middle Carson

Surface-Groundwater GSFLOW Model

Carson Valley and Middle Carson

Operations

MODSIM Model

Stakeholderinformed drought

scenario

Carson River basin:• Storages are snow and

groundwater• Water use is dominated by

agriculture

Truckee River basin:• Storages are lakes/reservoirs• Water uses are dominated by

municipal and industrial

Snowpack, rain, reservoir, and groundwater storage forecast

Runoff to rivers

Water allocations for agricultural, municipal, and industrial uses

Photo credit: Republic Manufacturing

Human Decision Making and Climate Variability/Change

Challenges

• Balancing competing interests in supply and demand

– Increasing and diverse demands for water

– Decreasing and variable water supplies

– Urban population growth

– Expanding industrial use

– Ecosystem protection

• Climate and policy uncertainties

– Complex historical legal constructs for water allocations

– Major shifts in snowpack dynamics

– Decision-making under consecutive years of scarcity impact stakeholder communities differently

– Drivers for drought and impacts of climate change not uniform in arid land river systems

Truckee Irrigation Canal (Aug 2015)

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What happens when it snows during a drought?

NSF-WSC Water for the Seasons Feb15 22

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Questions