Western U.S. Observed Hydrology & Vegetation Changes
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Transcript of Western U.S. Observed Hydrology & Vegetation Changes
Paul R. Houser, Science AdvisorPaul R. Houser, Science Advisor
Western U.S.Observed Hydrology & Vegetation Changes
Less Spring Snowpack
Cayan et al., 2001
Earlier Greening
Stewart et al., 2005
Earlier Snowmelt Runoff Less Snow, More Rain
Increasing Temperature
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
Reclamation Climate Studies
• Climate Change and Water Working Group (CCAWWG): NOAA, USGS, USACE, EPA, NASA, FEMA collaboration
• Climate change is occurring; effects differ regionally.• Water resources management could be affected; hydroclimate conditions becoming non-
stationary.• Climate change is one of many challenges facing water managers.
From USGS Circular 1331 (Brekke et al. 2009)
• Federal agencies that conduct water management have a responsibility to take a lead role in assessing risks to the water resources and to develop adaptation and mitigation strategies
2009 SECURE Water Act (PL 111-11)
• Establishes Landscape Conservation Cooperatives, Climate Science Centers, and Basin Studies
Secretarial Order 3289 and 3297 – WaterSMART
http://www.usbr.gov/climate
Paul R. Houser, Science Advisor
West-Wide Climate Risk Assessments (WWCRA) - Hydrologic Projections (2011)
http://www.usbr.gov/WaterSMART/wwcra.html
112 Transient Climate Projections…http://gdo-dcp.ucllnl.org/downscaled_cmip3_projections/dcpInterface.html
8 “big basin” VIC hydrology model-apps from Univ. of WA…
112 Transient Hydrologic Projections covering western U.S.…
Analyses of Period-changes in climate and hydrology
SECURE Report to Congress, 2011 focus on median changes; future reports have broader scope
Technical Report, data-development (TSC 86-68210, March 2011)
Data-service, Reclamation and broader public use (Summer 2011)
Peer
Rev
iew
Paul R. Houser, Science Advisor
Colorado River Change Through Time2020s 2050s 2070s
Temp
Precip
Snow
1950 2000 2050 2100
50
100
150
Colorado River above Imperial Dam
Annu
al M
ax. W
eek
Run
off,
kcfs
Water Year
• Flood Control Implications
• Environmental Flow Implications
HUGE CAVEAT – e.g. calibration, validation
Annual Max Weekly Runoff
1950 2000 2050 2100
6
8
10
Colorado River above Imperial Dam
Annu
al M
in. W
eek
Run
off,
kcfs
Water Year
Annual Min Weekly Runoff
Paul R. Houser, Science Advisor
SEC
UR
E R
epor
t: W
estw
ide
Impa
cts
(e.g
. ann
ual a
nd s
easo
nal r
unof
f)annual Dec-Mar Apr-Jul
2020
s-19
90s
2050
s-19
90s
2070
s-19
90s
http
://ww
w.us
br.g
ov/c
limat
e