Climate Change and Flooding - Home - CRITFC · large areas -- e.g., all coastal ... Guillaume...
19
Climate Change and Flooding Guillaume Mauger Climate Impacts Group
Transcript of Climate Change and Flooding - Home - CRITFC · large areas -- e.g., all coastal ... Guillaume...
ClimateChangeandFlooding
Guillaume Mauger Climate Impacts Group
SeaLevelRise
PhotobyHughShipman,WADept.ofEcology
• Pastcentury:about+8in.
• By2100:+24in.(range:+4to+56in.)
• Localratesofrisevary.
• Noincreaseinstormsurge,buthigherseaswillcarrysurgefartherinland.
AlkiBeach,WestSeaQle,January21,2010PhotobyHughShipman,WADept.ofEcology
(
Ourprimarymechanismforstoringwater–snow–issensi:vetowarming.
Snow
April1stSnowpackinWA:
• Since1950:about−25%
• 2080s,averageprojecVon:−56to−70%.
Historical
Samish River
Oct Dec Feb Apr Jun Aug
200
400
600
800
1000
Rain dominant (Green)
Month
Nat
ural
flow
(cfs
)
Snohomish River
Oct Dec Feb Apr Jun Aug
3000
9000
1500
021
000
Mixed rain and snow (Red)
Month
Sauk River
Oct Dec Feb Apr Jun Aug
020
4060
8010
0
Snow dominant (Blue)
Month
Snow has a major effect on streamflow.
HistoricalA1B 2040s
Samish River
Oct Dec Feb Apr Jun Aug
200
400
600
800
1000
Rain dominant (Green)
Month
Natu
ral f
low
(cfs
)
Snohomish River
Oct Dec Feb Apr Jun Aug
3000
9000
1500
021
000
Mixed rain and snow (Red)
Month
Sauk River
Oct Dec Feb Apr Jun Aug
020
4060
8010
0
Snow dominant (Blue)
Month
HistoricalA1B 2040sA1B 2080s
Samish River
Oct Dec Feb Apr Jun Aug
200
400
600
800
1000
Rain dominant (Green)
Month
Natu
ral f
low
(cfs
)
Snohomish River
Oct Dec Feb Apr Jun Aug
3000
9000
1500
021
000
Mixed rain and snow (Red)
Month
Sauk River
Oct Dec Feb Apr Jun Aug
020
4060
8010
0
Snow dominant (Blue)
Month
Snowkeepswateroutoftheriverswhenwedon’twantit,andreleasesitwhenwedo.
Warner,Mass,Salathé,JHydromet,2014
More Intense Heavy Rains
Heaviestraineventsareprojectedtobecome+22%moreintense(range:+5to+34%)bythe2080s.
ResultsfromStaVsVcalDownscalingNot much change in cold basins that remain snow-dominant
Increased risk in cool basins transitional between snow and rain-dominance
WarmBasinsColdBasins
Increased flood risk
!
Dec
reas
ed
flood
risk
"
Incr
ease
d flo
od ri
sk
Salathéetal2014
Not much change in warm basins that remain rain-dominant
WarmBasinsColdBasins
More scatter due to variability in storminess
Big increase in Rain-driven Events
Salathéetal2014
Increased risk in cool basins transitional between snow and rain-dominance
ResultsfromDynamicalDownscaling
cig.uw.edu
2015
Increasingwinterfloodrisk
e.g.:InthelowerSnohomishRiver,bythe2080s,the“10-year”floodisprojectedtobecomea3-yearevent.
VisualizingFloodRisk
Existing conditions of Walmart in Mount Vernon, WA.
Visual simulation of Walmart in Mount Vernon, WA during a major fl ood event (the FEMA 100-year fl ood). Floodwaters are estimated to rise 10.6 feet above ground elevation at this site.
FILE
NA
ME
: SC
2_ph
otos
im_2
015-
09-1
1.in
dd /
CR
EAT
ED
BY:
GW
B /
DAT
E: 0
9-11
-201
5
Existing conditions of Walmart in Mount Vernon, WA.
Visual simulation of Walmart in Mount Vernon, WA during a major fl ood event (the FEMA 100-year fl ood). Floodwaters are estimated to rise 10.6 feet above ground elevation at this site.
FILE
NA
ME
: SC
2_ph
otos
im_2
015-
09-1
1.in
dd /
CR
EAT
ED
BY:
GW
B /
DAT
E: 0
9-11
-201
5
SeaLevelRise,Peakflows,&Flooding
hQp://www.skagitclimatescience.org/flood-scenario-map/
Results
www.maps.coastalresilience.org/pugetsound
10-yearFlood,Historical(1980s)
Results
www.maps.coastalresilience.org/pugetsound
10-yearFlood,A1b2080s,Low
Results
www.maps.coastalresilience.org/pugetsound
10-yearFlood,A1b2080s,High
Results
www.maps.coastalresilience.org/pugetsound
100-yearFlood,Historical(1980s)
Results
www.maps.coastalresilience.org/pugetsound
100-yearFlood,A1b2080s,Low
Results
www.maps.coastalresilience.org/pugetsound
100-yearFlood,A1b2080s,High
Wehavethetoolstoimproveoverthepiecemealapproach.
Environ Fluid Mech
Fig. 1 Study domain—Skagit River Estuary and Middle Skagit Floodplain (upper panel) and observed veloc-ity transects in the Middle Skagit River (lower panel)
3 Methodology
3.1 Data
Data used in this study can be divided into two groups: (1) data required for the model setupand (2) data used for the model calibration. Data required for the model setup consist ofgeometry and bathymetry data for the study domain and the boundary forcing data to drivethe model. Model calibration data include observed values of physical properties to calibratethe model parameters and assess the model performance in simulating the hydrodynamics inthe estuarine and upstream river floodplain regions.
123
Environ Fluid Mech
Fig. 2 Model grids and water depths in Skagit Bay (upper panel) and upstream reach of Middle Skagit River(lower panel)
The focus of this study is to demonstrate a coastal modeling capability to simulate thehydrodynamics in both estuarine and river floodplain regimes in an integrated modelingframework. Therefore, meteorological forcings (wind, heat flux, precipitation, and evapora-tion) and temperature simulations were not considered in this study.
123
Yang,Z.,Wang,T.,Khangaonkar,T.,&Breithaupt,S.(2012).Integratedmodelingoffloodflowsand<dalhydrodynamicsoveracoastalfloodplain.Envir.FluidMech.,12(1),63-80.
Expandfloodmodelstocoverlargeareas--e.g.,allcoastalfloodplainsinWA.
