climate change in the green- the green/duwamish river ...€¦ · 26.10.2016 · duwamish estuary...
TRANSCRIPT
.PIERCE CO.
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Watershed Boundary
Basin Boundary
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Department of Natural Resources and ParksWater and Land Resources Division
The Green/Duwamish RiverWatershed
Produced by:Department of Natural Resources and Parks, WLRD,GIS, Visual Communications & Web UnitFile Name: 0605greenbase sk
LowerGreen RiverSubwatershed
MiddleGreen River
Subwatershed
UpperGreen RiverSubwatershed
Duwamish EstuarySubwatershed
Climate Change in the Green-Duwamish Watershed
Impacts on the Physical, Natural, and Human
Environment
Guillaume Mauger Climate Impacts Group WRIA 9, 26 Oct 2016
ClosingtheClimateGap
Science Prac*ce
“whatweknow”
“whatwe’redoingaboutit”
cig.uw.edu
2015
Scoping Climate Science and Decision-Support Needs for Floodplain Management in Puget Sound
Guillaume Mauger, Climate Impacts Group, UW
Overview
The purpose of this document is to begin defining an agenda for the science and engagement efforts needed to support the consideration of climate change in multi-objective floodplain management. To do this, we propose a 3-tiered approach involving work at the regional, watershed, and project scales (Table 2). At each level, efforts to advance the science will be accompanied by stakeholder engagement aimed at defining science priorities and advancing the capacity to incorporate climate impacts in decision-making.
In the sections below we have summarized a number of actions, with their associated outcomes, assuming that the geographic scope is limited to the Puget Sound catchment. In writing the descriptions below, specific watersheds and projects have intentionally been omitted from the descriptions. Over the course of this project, it became clear that the discussions needed to identify the specific science and data needs of each stakeholder or project would require much more than was scoped for the current effort. Instead, we have distilled the results of these conversations into a set of research gaps that would address a wide range of planning and project needs, as well as a number of actions that would serve to further elucidate the science needed to support multi-objective floodplain management in the region.
Both feasibility and cost for this work will depend on the exact combination of efforts, priorities, and funding that is available for leverage. Moreover, these efforts can be undertaken by any number of entities in the region, depending on suitability and expertise. Nearly all of the efforts would require some degree of collaboration; potential partners include the many agencies, non-profits, and other institutions in the region.
Finally, it is important to emphasize that the tasks outlined in this document are intended to be a starting point for discussion. A comprehensive assessment of research gaps would require a larger evaluation involving researchers and stakeholders with varying points of view and expertise.
Table 1. Climate Architecture for Developing a Research Approach and Climate Work Plan for TNC.
Risk and Opportunity Assessment/Education
Policy and Planning
Implementation
Working with stakeholders to identify key interests and concerns, and developing science and data products that are tailored to decision needs.
Institutionalizing climate in regional funding, permitting, and policy decisions
Where to place projects to address specific climate risk, and how high to build your new levee.
Project/Reach Scale
The Lower XX river reach is at increased risk due to sea level rise, increased sedimentation and increased flood frequency and magnitude (all could be quantified). Tributary flows, engineered protections, agriculture and habitat considerations, or other specific issues are incorporated when focusing in on the project scale.
Updates to CFHMP, Salmon plans, and other plans include watershed-specific climate information, providing a basis for evaluating project ideas and prioritizing them relative to one another.
Lower XX and XX Creek suite of projects identified and designed to be resilient to climate change.
Watershed
Peak and low flows, reservoir operations, stream temperature, sediment transport, and hydrodynamic modeling necessary to make reach scale conclusions.
Projects are implemented in the headwaters to retain sediment and flood waters while parallel acquisition efforts retain opportunity in the floodplains.
Regional
Every major floodplain in Puget Sound will experience increases in 100-year flood events ranging from an increase of 18-55%, on average, however floodplain vulnerabilities extend beyond flooding, including sediment, water temperatures, sea level rise. Regional resources are targeted and sequenced as informed by climate risk/opportunity.
Ecology and PSP budgets and research plans; Legislative support; State and federal guidance documents.
Funding is driven towards research (analysis, modeling and data collection), monitoring, and implementation of projects that are deemed necessary in the face of climate change.
Playingthelongandtheshortgame
Awareness
Assessment
Analysis
Planning
Photo credit: Marli Miller
Climate Impacts
What does the science tell us?
2000 2050 2100
400
600
800
1000
1200
Year
CO2−
equi
vale
nt c
once
ntra
tion
(ppm
)
SRES A1FIRCP 8.5SRES A2RCP 6.0SRES A1bRCP 4.5SRES B1RCP 2.6OBS
Greenhouse gas “scenarios” are best guesses about future emissions
Substantial Warming, Variable Rainfall
Historical
Low Emissions (RCP 4.5)
High Emissions (RCP 8.5)
1950 1975 2000 2025 2050 2075 2100
0°F
5°F
10°F
15°F
0°F
5°F
10°F
15°F
Year
Temperature Difference(Relative to 1950−1999 average)
Year
Precipitation Change(Relative to 1950−1999 average)
1950 1975 2000 2025 2050 2075 2100
−40%
−20%
0%
20%
40%
60%
−40%
−20%
0%
20%
40%
60%
ClimateChange:PhysicalDrivers
SeaLevelRise
Warming,Rainfall
Forests,Freshwater
Surge/Waves,OceanpH
OceanAcidifica*on
• By2100,oceanpHisprojectedtodecreaseby–0.14to–0.32([H+]increaseof+38to+109%)
• VariabilityinupwellingcanstronglyaffectpH
SeaLevelRise
PhotobyHughShipman,WADept.ofEcology
• Pastcentury:about+8in.
• By2100:+24in.(range:+4to+56in.)
• Localratesofrisevary.
• Noincreaseinstormsurge,buthigherseaswillcarrysurgefartherinland.
AlkiBeach,WestSea`le,January21,2010PhotobyHughShipman,WADept.ofEcology
Warner,Mass,Salathé,JHydromet,2014
More Intense Heavy Rains
Heaviestraineventsareprojectedtobecome+22%moreintense(range:+5to+34%)bythe2080s.
(
Ourprimarymechanismforstoringwater–snow–issensiGvetowarming.
The Cascade and Olympic Mountains have the highest fraction of “warm snow” (snow falling between 27-32°F) in the continental U.S. (Mote et al. 2008)
Snow
April1stSnowpack:
• Since1950:about−25%
• 2080s,averageprojec*on:−37to−55%.
Historical
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
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.
WarmingStreamsBythe2080s:
• WarmingStreams:+4.0°Fto+4.5°F,onaverage.
• Numberofrivermilesexceedingthermaltolerancesareprojectedtoincreaseby>70mi.forsalmon,and>170mi.forchar Datasource:NorWeST,
Figure:ClimateImpactsGroup
Early peak flows
Floods
OA? SSTs?
Warm, low streamflow
Salmon Impacted Across Full Life-Cycle
EvaluaGngtheEffecGvenessofRestoraGonAcGons
Figuresource:Ba.netal.2007
yearling migrants primarily spawn in the upper watershed (16),where climate impacts are projected to be greatest.
Chinook salmon exhibit remarkable plasticity in many life-historytraits and may be able to respond evolutionarily or behaviorally toclimate change in ways not captured in our models. Our findings donot support the notion that fish will react to climate change bymoving to higher elevations (17), but they may be able to mitigatetemperature effects by sheltering in thermal refugia when temper-atures become too high (18). Although their need to lay eggs inareas of high subgravel flows (19) makes it unlikely that Chinook
could alter redd placement to avoid the effects of higher peak flows,changes in the timing of migration, egg laying, and other life stagesmay allow fish to prosper in altered habitats. More southerlypopulations of Chinook, which migrate and spawn later in the year,may provide a model for how Puget Sound populations will respondto warming, but climate change also may produce conditions unlikeanything currently experienced by salmon. Little is known about thecapacity of salmon to adjust to climate change, and the potential forevolutionary or behavioral responses is one of the most importantavenues for future research.
Habitat restoration can play an important role in offsetting theeffects of climate change, although our results suggest that mostexpected climate impacts cannot be mitigated entirely. In relativelynarrow streams, reforestation may decrease water temperatures byincreasing shading, but in wide, main-stem reaches where mostChinook salmon spawn, riparian vegetation has a minor effect onwater temperature. New reservoirs and flood-control structurescould mitigate flow impacts, but because these effects are likely tobe most severe in headwater streams, it is unlikely that such actionswould be feasible or desirable. As in many river basins, thehighest-elevation portions of the Snohomish watershed, whereprojected climate impacts are greatest, are largely protected andpristine, with little potential for further restoration. Although directmitigation of the hydrologic impacts of climate change may not bepossible, habitat restoration, particularly the restoration of juvenilerearing capacity, may benefit salmon populations threatened by
Fig. 3. Climate impacts on three hydrologic variables. (A1–A3) The results ofthe GFDL R30 climate model. (B1–B3) The results of the HadCM3 model. (Top)Percent change in incubation peak flow. (Middle) Percent change in minimumspawning flow. (Bottom) Change in prespawning temperature in degreesCelsius. The basin-wide average change is shown in the lower left corner ofeach figure. Black lines delineate subbasin boundaries. All simulations usedthe ‘‘current’’ land use scenario.
Fig. 4. Basin-wide percent change from 2000 in numbers of spawningChinook under different combinations of climate change and habitat resto-ration for the GFDL R30 (A) and HadCM3 (B) climate models.
Fig. 5. Change in spawning Chinook salmon abundance between 2000 and2050 under three future land-use scenarios. (A1–A3) The results of the GFDLR30 climate model. (B1–B3) The results of the HadCM3 model. (Top) Currentland-use scenario. (Middle) Moderate restoration scenario. (Bottom) Full res-toration scenario. The basin-wide total change appears in the lower leftcorner of each figure.
Battin et al. PNAS ! April 17, 2007 ! vol. 104 ! no. 16 ! 6723
SUST
AIN
ABI
LITY
SCIE
NCE
ECO
LOG
Y
yearling migrants primarily spawn in the upper watershed (16),where climate impacts are projected to be greatest.
Chinook salmon exhibit remarkable plasticity in many life-historytraits and may be able to respond evolutionarily or behaviorally toclimate change in ways not captured in our models. Our findings donot support the notion that fish will react to climate change bymoving to higher elevations (17), but they may be able to mitigatetemperature effects by sheltering in thermal refugia when temper-atures become too high (18). Although their need to lay eggs inareas of high subgravel flows (19) makes it unlikely that Chinook
could alter redd placement to avoid the effects of higher peak flows,changes in the timing of migration, egg laying, and other life stagesmay allow fish to prosper in altered habitats. More southerlypopulations of Chinook, which migrate and spawn later in the year,may provide a model for how Puget Sound populations will respondto warming, but climate change also may produce conditions unlikeanything currently experienced by salmon. Little is known about thecapacity of salmon to adjust to climate change, and the potential forevolutionary or behavioral responses is one of the most importantavenues for future research.
Habitat restoration can play an important role in offsetting theeffects of climate change, although our results suggest that mostexpected climate impacts cannot be mitigated entirely. In relativelynarrow streams, reforestation may decrease water temperatures byincreasing shading, but in wide, main-stem reaches where mostChinook salmon spawn, riparian vegetation has a minor effect onwater temperature. New reservoirs and flood-control structurescould mitigate flow impacts, but because these effects are likely tobe most severe in headwater streams, it is unlikely that such actionswould be feasible or desirable. As in many river basins, thehighest-elevation portions of the Snohomish watershed, whereprojected climate impacts are greatest, are largely protected andpristine, with little potential for further restoration. Although directmitigation of the hydrologic impacts of climate change may not bepossible, habitat restoration, particularly the restoration of juvenilerearing capacity, may benefit salmon populations threatened by
Fig. 3. Climate impacts on three hydrologic variables. (A1–A3) The results ofthe GFDL R30 climate model. (B1–B3) The results of the HadCM3 model. (Top)Percent change in incubation peak flow. (Middle) Percent change in minimumspawning flow. (Bottom) Change in prespawning temperature in degreesCelsius. The basin-wide average change is shown in the lower left corner ofeach figure. Black lines delineate subbasin boundaries. All simulations usedthe ‘‘current’’ land use scenario.
Fig. 4. Basin-wide percent change from 2000 in numbers of spawningChinook under different combinations of climate change and habitat resto-ration for the GFDL R30 (A) and HadCM3 (B) climate models.
Fig. 5. Change in spawning Chinook salmon abundance between 2000 and2050 under three future land-use scenarios. (A1–A3) The results of the GFDLR30 climate model. (B1–B3) The results of the HadCM3 model. (Top) Currentland-use scenario. (Middle) Moderate restoration scenario. (Bottom) Full res-toration scenario. The basin-wide total change appears in the lower leftcorner of each figure.
Battin et al. PNAS ! April 17, 2007 ! vol. 104 ! no. 16 ! 6723
SUST
AIN
ABI
LITY
SCIE
NCE
ECO
LOG
Y
Increased wildfire risk? Change in risk is unknown, but an increase is likely due to warmer summers, declining snowpack (Littell et al. 2010, 2012)
DiscoveryFireburnsnearvola*lestandsofinsect-damagedtrees,2009,DNR
Landslides
Geology and topography make the landscape vulnerable, but it is the hydrology that pulls the trigger.
-- Erkan Istanbulluoglu, UW CEE
Photo:DNR Photo:DNR
Sediment
Issue Example: Groundwater and Drainage Factors
Tide
River
Precipitation
Other factors…?
Poten7alTraitsofImportance• #ofhoursabovecurrentHigherHighTide• Ndegatedrainagewindow• groundwaterlevels• groundwatersalinity• …?
• averagewinterflow• floodfrequency• Nmingorlengthofspringrunoff• sedimentaccreNoninchannelsandmarsh• …?
• seasonalormonthlyaveragerainfall• 24hrmaxrainfall• …?
Hours Per Year
MHHW (approx. 2.75m)
Tidegate Drainage
For a tidegate that is slightly above the average higher high tide today:
2012 2050 2100 1 hr/dy 3 hrs/dy 8 hrs/dy
Hours of Tidal Inundation Per Year
2012
2050
2100
USGS
Groundwater
McLeanRoad
Hwy20
BestRoad
August2007
BigBend
Note:Thisisnotapredic*on,butisone plausiblescenario(i.e.:nomodeling).
August2100
USGS
h`ps://twi`er.com/LigaDos32h`p://www.abc.net.au/
Culverts
2
Figure 10. The mean (of 10 models) projected percent change in bankfull width for the A) 2040s and B) 2080s time periods. Black lines are ecoregion boundaries. Grid cells are 1/16-degree latitude x 1/16-degree longitude (approximately 5 x 7 km).
A
B Averageprojectedincrease(%)inbankfullwidth
2040s
2
Figure 10. The mean (of 10 models) projected percent change in bankfull width for the A) 2040s and B) 2080s time periods. Black lines are ecoregion boundaries. Grid cells are 1/16-degree latitude x 1/16-degree longitude (approximately 5 x 7 km).
A
B
IncreasingwinterfloodriskSeaLevelRise HeavierRains
DecliningSnowpack
InthelowerSnohomishRiver,bythe2080s,the“10-year”floodisprojectedtooccurevery3years.
Conclusion:Maybe.TheDamdoesalottoreducefloodriskandboostsummerflows.Reservoiropera*onscanaccommodatemostoftheprojectedchangesinstreamflow,butsimula*onssuggestahigherlikelihoodoffloodinginthelowerGreen.Moreworkisneededtoconfirm.
QuesNon:Willthereservoirs*llbeabletocontrolflowsinthefuture?
IncreasingFloodRisk Inunda7onmapping
h`p://maps.coastalresilience.org/pugetsound/
ClimatechangeandFlooding:SkagitRiver
h`p://www.skagitclimatescience.org/flood-scenario-map/
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
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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
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AddiNonalconsideraNons:ClimateChange,Tribes,andTribalHealth
• declineorlossofkeyplantandanimalspecies,• lossofreserva*onland,• lossofculturalsitestosealevelrise• lossorchangesintradi*onalfoods
Psychological stress from loss of cultural identity in Native cultures due to:
Coast Salish Canoe Journey 2009 landing in Pillar Point; photo by Carol Reiss, USGS
ThereareembeddedclimateexpectaGonsinnearlyeverythingwedo…
Atitscore,planningforclimatechangeisaboutriskmanagement
ThingstoLookFor
• Embeddedassump*onsofsta*onarity
• Ac*onspeggedtospecificthresholdsor*meperiods
• Qualita*vetermsthatcouldtakeonneworexpandedmeaning
1.IstheNTA(oritsfocus)sensiGvetochangesinclimate?
2.CantheNTAaccomplishitsintendedobjecGves“asis”?
No
Yes
Nofurtherac7onrequired.ClimatechangedoesnotneedtobetakenintoaccountinformulaNonandimplementaNonofthestrategy/NTA
No
Yes
Monitor.Strategy/NTAdoesnotneedtobeadjustedbutshouldbecheckedperiodicallyagainstupdatedclimateprojecNonstohelpensureeffecNvenessoverNme.
3.Whatspecificallyneedstobechanged?
Adap*ngtoClimateChange:NextSteps?
• Certaintyofprojec*ons• Rightspa*alscale• Cost• Timeframeofresearch• CCimpactrela*vetootherimpacts(i.e.,land-use)
• Newinforma*onrela*vetosocialrecep*vitytonewdirec*on
• Reducedrisk• Improvedac*ons• Costsavoided
Thedifferencebetweensciencethatis“usable”vs.“usedby”
ANot“Right-Designed”Study–Won’tHelpYOU--ItMightFitSomeoneElse…
(slidecourtesyofCarolMacIlroy)
[email protected](206)685-0317Climate Science in the
Public Interest
ExamplesofDeliveringAdaptaGonAcGons
• Increasewaterconserva*onmeasures
• Strengthendikesandleveeswhereappropriate
• Restorecri*calhabitatforclimate-sensi*vespecies
• Planttreespeciesknowntohaveabroadrangeoftolerances
• Improvetheuseofearlywarningsystemsforharmfulalgalblooms
• Increaseuseofsetbacksorrollingeasementsforcoastallanduses
ExamplesofBuildingAdapGveCapacity
• Increaseoutreachandeduca*ontostakeholdersaboutclimatechangeandadapta*on
• Increasestafftrainingopportuni*esandaccesstotechnologiesthatsupportadapta*onneeds
• Increasepartnershipswithorganiza*onsthatcansupportadapta*onneeds
• Iden*fyandaddressregulatory,ins*tu*onal,andotherbarrierstoadapta*onplanning
• Iden*fyandaddresskeyinforma*ongaps