Transcript BOR-Climatex

Reclamation Climate Change Activities
Paul R. Houser
Paul R. Houser, Science Advisor
Reclamation
Mission
The mission of the
Bureau of Reclamation is
to manage, develop, and
protect water and
related resources in an
environmentally and
economically sound
manner in the interest of
the American public.
Paul R. Houser, Science Advisor
Observed Hydrology & Vegetation Changes
Less snow/more rain
Earlier greenup
Cayan et al., 2001
Less spring snowpack
TRENDS (1950-97) in
April 1 snow-water content at
western snow courses
Earlier snowmelt runoff
Stewart et al., 2005
Mote, 2003
Figs. M. Dettinger (USGS)
Paul R. Houser, Science Advisor
Implications for water supplies, water
demands, operating constraints?
• Supplies
– warming
• less snowpack  less controllable water supply
• more landscape evapotranspiration (ET)  less runoff
– precipitation change? could be + or - , help or worsen…
• Demands
– warming
• Irrigation: increased seasonal water demand (longer season, more ET)
• Electricity: increased summer demand, decreased winter demand
• Operating Constraints
– Environment – instream flow requirements?
• Reduction in cold-water supplies
– Flood Protection – storage reservation requirement?
• All other things equal, warming leads to greater area contributing runoff during western
winter storm events – greater winter reservoir drafts?
• Storm intensification could be + or -, worsen or help…
Paul R. Houser, Science Advisor
Key Challenges for Reclamation
• Understand how climate variability and change can
affect Western water supply and demand, and
Reclamation delivery of water given operational
constraints (i.e. environmental constraints, flood
constraints)
• Bring science and technology to bear on the needs of
water resources managers
• Address goals of internal programs and authorizations
where climate change is a factor
Paul R. Houser, Science Advisor
West-Wide Climate Risk Assessments
(WWCRA) - Hydrologic Projections (2011)
112 Transient Climate Projections…
http://gdo-dcp.ucllnl.org/downscaled_cmip3_projections/dcpInterface.html
112 Transient Hydrologic
Projections covering
western U.S.…
SECURE Report to
Congress, 2011
focus on median
changes; future
reports have broader
scope
Analyses of Periodchanges in climate
and hydrology
8 “big basin” VIC
hydrology model-apps
from Univ. of WA…
Data-service,
Reclamation and
broader public use
(Summer 2011)
http://www.usbr.gov/WaterSMART/wwcra.html
Technical Report,
data-development
(TSC 86-68210,
March 2011)
Paul R. Houser, Science Advisor
SECURE Report Production
• Funding
• WaterSMART Basin
Study Program –
West-Wide Climate
Risk Assessment
• Supporting:
• Secretarial Orders
3289 and 3297
Paul R. Houser, Science Advisor
Future Climate / Hydrology
Baseline
Change Through Time
2020s
2050s
Temp
Precip
Snow
Paul R. Houser, Science Advisor
2070s
Tying to Impacts Example
Colorado Flow Timing
•Flow timing shifts towards
additional cool season runoff.
•Reduced warm season runoff
Competing Questions
•Floods - Increased drawdown
requirements to maintain risk
objectives
•Storage - Able to refill to supply
objectives
Paul R. Houser, Science Advisor
Annual Max. Week Runoff, kcfs
Tying to Impacts
Colorado River Example
Environmental and Flood Control
Colorado River above Imperial Dam
150
100
50
1950
2000
2050
2100
Implications for
Flood Control
Objectives
Annual Min. Week Runoff, kcfs
Water Year
Colorado River above Imperial Dam
10
8
6
1950
2000
2050
2100
Water Year
Implications for
Environmental
Flow
Objectives
HUGE CAVEAT – e.g. calibration, validation
Paul R. Houser, Science Advisor
2070s-1990s
2050s-1990s
2020s-1990s
SECURE Report: Westwide Impacts
(e.g. annual and seasonal runoff)
annual
Dec-Mar
Paul R. Houser, Science Advisor
Apr-Jul
Colorado River Basin Water Supply
and Demand Study
Paul R. Houser, Science Advisor
Annual Colorado River Water Supply & Use
Paul R. Houser, Science Advisor
Water Supply Scenarios *
Water Demand Scenarios *
Observed Resampled:
Current Trends:
 future hydrologic trends and variability
will be similar to the past 100 years
 growth, development patterns, and
institutions continue along recent trends
Paleo Resampled:
Economic Slowdown:
 future hydrologic trends and variability
are represented by the distant past
(approximately 1250 years)
 low growth with emphasis on economic
efficiency
Paleo Conditioned:
 economic resurgence (population and
energy) and current preferences toward
human and environmental values *
 future hydrologic trends and variability
are represented by a blend of the wet
dry states of the paleo-climate record
but magnitudes are more similar to the
observed period
Downscaled GCM Projected:
 future climate will continue to warm with
regional precipitation trends represented
through an ensemble of future GCM
projections
Expansive Growth:
Enhanced Environment and Healthy
Economy:
 expanded environmental awareness and
stewardship with growing economy*
* Additional “branches” possible depending upon
assumed trajectory of specific socio-economic
factors.
* Preliminary – Subject to change
Paul R. Houser, Science Advisor
Integration of Supply and Demand Scenarios
Water Supply Scenarios
(multiple realizations for each
scenario)
Water Demand
Scenarios
Recent
Trends
Recent
Trends
Climate indexing for demands
Paul R. Houser, Science Advisor
Addressing an Uncertain Future
• The path of major influences on the
Colorado River system is uncertain and
can not be represented by a single view
• An infinite number of
plausible futures exist
Scenario
Funnel
• A manageable and
informative number of
scenarios are being
developed to explore the
broad range of futures
Paul R. Houser, Science Advisor
Thank You
Questions?
Paul R. Houser, Science Advisor