453
1 INTRODUCTION
AccordingtoNichollset al.[8],portcitiesareavital
component of the global economy and are
increasingly becoming important concentrations of
populationandassetvalue.Thirteenoutofthetwenty
mostpopulatedcitiesintheworldin2005wereport
cities.
Sealevelrise(SLR)and
theincreasingoccurrence
of stronger storm surge events in metropolitan
regions of ports cities with more than one million
inhabitantsin2005wereanalyzedbyNichollsetal.[8]
and ranked according to exposed population and
assetsin2005and2070,includingSantos(Brazil).
SantosPortis situatedinSantos
Estuary,State of
São Paulo Coast (Figure 1), is the largest multi‐
purposeportinSouthAmericawithoverthan16km
ofquays.Peryear,athroughputof120milliontonsof
cargoismade[2].
The estimation about the magnitude of SLR in
recommendations,guidelinesorrequirementsissued
by
different countries and agencies [3] provide
examples of different approaches used around the
world in comparison with the local trends obtained
forSantosPort.
São Paulo State Coast has a linear length of 500
km.Hence,twootherlocations,Cananeia(200kmSW
of Santos) and Ubatuba (150 km NE
of Santos), see
Figure1,hadtheirSLRcomparedwithSantos,which
is considered the Central Littoral of São Paulo State
Coast.
The objective of this paper is to check the
similarityofSantosSLRwithnearbylocationsofSão
Estimation of Sea Level Rise in Santos Port (Brazil)
P.Alfredini&E.Arasaki
SaoPauloUniversity,SãoPaulo,Brazil
ABSTRACT: Santos Port is located in São Paulo State Coast (Brazil), inanestuarine area inside Santos Bay
namedBaixadaSantista.Thecurrentsbehaviorisforcedbytides.Theresultingtidallevelvariability(hightide,
meansealevelandlowtide)recordedfromSantosDock
Companytidegauge(1940to2014),thelongestseries
ofcontinuousrecordoftidesinBrazil,showsaconsistentincreasingtrend.Theestimationaboutthemagnitude
ofmeansealevelrise(MSLR)inrecommendations,guidelinesorrequirementsissuedbydifferentcountries
andagenciesfrom1990provideexamplesofdifferentapproaches
usedaroundtheworldincomparisonwith
thelocaltrendsobtainedforSantosPort.ItisconcludedthatMSLRwillhaveaconsiderableimpactuponthe
port,withapproximately1.0mriseestimatedfrom1990to2100.BaixadaSantistaisalowlandsituatedafew
metersupperfromthesealevel
andsomeareasarepossibletobesubmergedintheendofthiscentury.Other
twolocationsinSãoPauloStateCoast,CananeiaandUbatuba,respectivelytotheSEandNWofSantos,were
alsocomparedwiththeporttidaldatatoevaluatetheconsistencyofthetrends.
http://www.transnav.eu
the International Journal
on Marine Navigation
and Safety of Sea Transportation
Volume 13
Number 2
June 2019
DOI:10.12716/1001.13.02.25
454
Paulo State Coast and classify the SLR according
internationalguidelinesknown.
2 MATERIAL
2.1 Tidesandmeansealevel(MSL)variabilityinSantos
Port
Longtermsealevelobservationsareusefulformany
researches as: tidal analyses, tidal modeling, studies
oftheoceandynamicsandevaluationofgreenhouse
impacts.Beside
these,worksontheestimationofthe
MSL trends and periodicities were developed in the
lastyearsinordertoestimatetheratesofchangesof
thesealevel[4,7 and10]. Theseworks, considering
different long series of sea level, studied the long‐
termtrendsofeachlocation.
2.2 SLRimpactsonportoperationandthesurrounding
neighborhood
These problems, discussed in [1, 2 and 10], are
basically consequences of the reduction of quays
freeboard,floodingduetoinsufficienteffectivenessof
the present drainage system and the increasing
sedimentation in the nautical areas.The increasing
in the salinity intrusion
upward the estuary due to
higher tidal levels will seriously affect the riparian
mangroves and will reduce this fine sediment trap.
Without this retention, a larger amount of sediment
will be carried to the inner nautical areas of Santos
Port,siltingand increasingthedredging volumes of
maintenance.
Make available
information on the impacts of
climatechangeonthemaritimeportenvironmenthas
become an international issue for ports to address
globalwarmingimpacts[10].
The exact coordinates of the three tide gauges of
thisstudy,accordingto[5and6]are:
SantosPort:23°57.3’S;46°18.6’W
Cananeia:25°01.0’S;47°55.7’W
Ubatuba:23°28.8’S;45°04.9’W
The tide gauge, which measured water level
fluctuationsinSantosPort,providedexactfourlunar
nodal periods (1940 until 2014) of 18.61 years each
one. It is the longest series of continuous record of
tides in Brazil and shows a consistent increasing
trend.This is an important astronomical criterion,
because take in account complete cycles of
repeatabilityoftheMooninfluenceontheMSLtrend,
which estimation make possible to evaluate with
reliability if the tidal level shows a MSLR after
completedeachcycle.For
eachyearwasplottedthree
dots:
MSL
HHW(HighestHighWater)
LLW(LowestLowWater)
The tide gauge of Cananeia belongs to
Oceanographic Institute of São Paulo University
(IOUSP). Exact two lunar nodal periods (1957 until
1993)wereselected[6].
ThetidegaugeofUbatubabelongedto
Geological
and Geographic Institute of São Paulo State (IGC).
Exacttwolunarnodalperiods(1954until1991)were
selected. This series has many gaps in the recorded
tidelevel, butis thebest forthe NorthofSãoPaulo
StateCoast.Forthisreason,itwasemployedmonthly
datatoincrease
thestatisticsevaluation[3].
3 METHODS
The Projected SLR resulting from simulations of
differentclimatescenariossincetheworkundertaken
bytheIPCC[5]increasesfrom1986–2005to2081–
2100intherangefrom0.26to0.82m.However,itis
evidentthataMSLRinthe
rangeof0.40to0.63m,i.e.
intheorderof0.50min2081‐2100isexpectedasan
averageofallthemodelingresultsreportedinIPCC
[7].
Figure1.MapofSãoPauloStateCoast.Locationofthestudyarea,showingSantosPort,CananeiaandUbatuba.
455
A likely scenario to use as practical
recommendation seems to be that the SLR in year
2100willbeintherangeof0.5mto1.0m,however
withariskofbeingabout50%higherandthatthesea
level will continue rising also after year 2100,
according
toTable1[9].
There are many approaches for determining an
appropriate MSLR scenario, but it is impossible to
predictexactlyhowthefuturesealevelwilldevelop.
Consequently, various authorities have developed
differentestimations[9]asfollows.
As example of local practices, the DEFRA –
DepartmentforEnvironment,Food
&RuralAffairsof
the UK Government [4] in anticipation of increased
futureSLR,recommendthatnewengineeringprojects
witha100‐yeardesignlifearerequiredtoincludeup
to1mofSLRfrom1990,recognizingthattherateof
riseisexpectedtobelargerattheend
ofthiscentury
thanatthebeginningofthecentury(Table2).Other
local practices mentioned by PIANC [3] are the
projections of the Delta Commission in The
Netherlands(projectingupto1.4mMSLRfrom1990
to 2100 and for USA: California, Oregon and
WashingtonStates(Table3)from
2000.
Consideringtheperiodfrom1990until2014asan
adjustmentperiodforthecalibrationoftheMSLRrate
obtainedfromthetidegaugeofSantosPort,thiswas
compared with the rates of UK [4] (moderate rate),
StatesofCalifornia,WashingtonandOregon[3],The
Netherlands Delta Project (equivalent to
Rahmstorf
[11], higher rate), PIANC [9] higher and lower rate,
IPCC [7] higher and lower rate and Rahmstorf [11]
lowerrate.Fromtheserates,wasadoptedthebestfit
toforecastMSLRrateforSantosPorttill2100.
Table1. Example of scenario for sea level rise (SLR) as
function of type of infrastructure impacted by the design
eventaccordingtoPIANC[3].
_______________________________________________
TypeofSeverityofTypicalSLR(m)inyear
infrastructure failure 2030 2050 2100 Laterthan
2100
_______________________________________________
Farmlandand low 0.1‐ 0.2‐ 0.5‐ Upto1.2
recreational0.2 0.4 1.0
facilities
Habitationand medium 0.15‐ 0.3‐ 1.0‐ Upto1.5
infrastructure0.3 0.6 1.2
Majorhabitation, high 0.2‐ 0.4‐ 1.1‐ Upto2.0
infrastructure0.4 0.8 1.5 orhigher
andpublicutilities
_______________________________________________
Table2. UK recommended net SLR rates and cumulative
amounts,relativeto1990[4].
_______________________________________________
Time LowrateModeraterate Highrate
period (mm/yr)/(mm/yr)/ (mm/yr)/
cumulativecumulative cumulative
SLRsinceSLRsince SLRsince
1990(m)at1990(m)at 1990(m)at
endofperiod endofperiodendofperiod
_______________________________________________
1990‐2025 2.5/0.093.5/0.124.0/0.14
2025‐2055 7.0/0.308.0/0.368.5/0.40
2055‐2085 10.0/0.6011.5/0.7112/0.75
2085‐2115 13.0/0.9914.5/1.1415/1.21
_______________________________________________
Table3. SLR projections relative to year 2000 for Seattle,
Newport,SanFranciscoandLosAngeles[3].
_______________________________________________
Cities203020502100
Projection Projection Projection
(cm)(cm)(cm)
_______________________________________________
Seattle6.6±5.6 16.6±10.5 61.8±29.3
Newport 6.8±5.6 17.2±10.3 63.3±28.3
SanFrancisco 14.4±5.0 28.0±9.2 91.9±25.5
LosAngeles 14.7±5.0 28.4±9.0 93.1±24.9
_______________________________________________
Finally, the MSLR results from Cananeia and
UbatubawerecomparedwithSantos.
In addition to the MSLR, in each locality the
maximum high‐tide and the lowest low‐tide were
plottedconsideringalinearfit.Obviously,thislinear
adjustment is not the best (R
2
low), but it gives a
tendentialgradientofMSLR.
4 RESULTS
In the graph of Figure 2 is presented Santos Port
annual tidal level variability from 1940 to 2014 and
thelineartrendsofMSL,HHWandLLW.Thevertical
levelemployedCDS(SantosDockCompany)datum.
In the graph
of Figure 3 is presented the mobile
average of 19 years (approximately the lunar nodal
period),showingaconsistentincreasing oftheMSL.
From 1940 to 2014, the linear gradient of the MSLR
was0.33cm/year witha coefficientof determination
R
2
= 0.4673, relatively high for this kind of
phenomena.
AsitispossibletoseeinFigure4,thebestfitofthe
calibrationforthelinearMSLRtrendof0.33cm/year
was obtained with UK MSLR moderate rate (0.35
cm/year from 1990 to 2014). Hence, the forecasting
linear trends
for Santos Port were plotted following
Table2moderateratefrom2014to2100.
The resulting MSLR from 1940 to 2100 shows a
consistent increasing trend, indeed, compare the
followingforecastsfor2100withreferenceto1940:
174.8cm:PIANC[3]higherrate.
156.5cm:TheNetherlands(Rahmstorf,[11],
higher
rate).
134.8cm:PIANC[9]lowerrate.
112.3cm:CaliforniaState.
108.9 cm: linear trend of the record of the tide
gauge of Santos Port from 1940 to 2014 and
adjustedfrom2014withUK[4]moderaterate.
108.3cm:IPCC[7]higherrate.
82.4cm:OregonandWashingtonStates.
54.5cm:Rahmstorf[11]lowerrate.
47.0cm:IPCC[7]lowerrate.
108.9cm:Averagevalueofthementionednine
MSLRestimationsfrom1940to2100.Itisexactly
equal for Santos Port MSLR rate proposed in this
paper.
MSLRfor
theotherlocationsresultedin:
Cananeia:0.38cm/yearwithR
2
=0.5795(Figure5).
TheverticallevelemployedIOUSPdatum.
Ubatuba:0.23cm/yearwithR
2
=0.1412(Figure6).
TheverticallevelemployedIGCdatum.
456
The average MSLR between the two locations is
0,31cm/year.
5 DISCUSSION
MSLR trend of Santos Port tide gauge from 1990 to
2014 was compared with the recommended rates of
UK [11] (moderate rate), States of California,
Washington and Oregon [9], The Netherlands Delta
Project(equivalentto[11]higherrate),
[9]higherand
lower rate,[7]higherand lower rate and [11]lower
rate. The best adjustment occurred with UK
recommended rate [4] (moderate rate), but also
CaliforniaStateand[9]higherratesarequitesimilar.
The average MSLR from 1940 to 2100 from all the
mentioned methods is identical
of Santos Port
projectionto2100usingUK[4](moderaterate).This
isan importantresult,andalsoshowingconsistence
withthe0.31cm/year,averageMSLRoftheothertwo
locationsofSãoPauloStateCoast,verycloseto 0.33
cm/year,estimatedforSantosPort.
The linear trends rates for HHW
and LLW are
rather more disperse, but all of them pointing for a
tide level rise. This pattern of dispersion was
expected, because of the randomic effect of
meteorologicaltides.
6 CONCLUSIONS
The assessment of MSLR in Santos Port shows a
reliable consistence in comparison with several
internationalrecommendationsand
alsowithsimilar
trendsinothertwolocationsofSãoPauloStateCoast
, giving confidence to its use for estimative impacts
duetothemaritimeconsequencesofclimatechanges.
The estimative of MSLR from 1940 to 2100 is 1.1 m,
following from 1940 to 2014 a rate of 0.33 cm/year,
whichshouldincreaseinthenextdecadesinasimilar
trend of UK recommendations for a moderate
scenario.
Figure2. Graphof Santos Port annual tidal levelvariability from1940 to 2014. Linear trendsof MSL (Mean Sea Level),
HHW(HighestHighWater)andLLW(LowestLowWater).
Figure3. Graph of tide mobile average of 19 years for MSL, HHW and LLW in Santos Port. It is possible to observe a
consistentSLRofthelevelsfrom1990.
457
Figure4.GraphofSantosPortMSLlineartrend from1940to2014,withtheperiodofadjustment (1990 to 2014) for the
selectionofthebestfitamongsomeofthemostknownproposedinternationalrecommendations.Projectionfrom1990to
2100forSantosPortMSLtrendadjustedandcomparisonswith
theinternationalguidelines.
Figure5.GraphofCananeiaannualtidallevelvariabilityfrom1957to1993.LineartrendsofMSL(MeanSeaLevel),HHW
(HighestHighWater)andLLW(LowestLowWater).
Figure6.GraphofUbatubamonthlytidallevelvariabilityfrom1954to1991.LineartrendsofMSL(MeanSeaLevel),HHW
(HighestHighWater)andLLW(LowestLowWater).
458
REFERENCES
Alfredini,P.;Arasaki,E.,andPezzoli,A.,2015.Theimpact
of sea level rise in Santos Port (Brazil) for the next
decades. Proceedings of 36th Congress of the International
Association of Hydraulic Research (The Hague, The
Netherlands),Paper84810.
Alfredini,P.andArasaki,E.,2018.Estimationandimpacts
of sea level
rise in Santos Port and adjacent areas
(Brazil). TransNav, the International Journal on Marine
NavigationandSafetyofSeaTransportation,12,739‐744.
Cartacho, D. L. Análise probabilística chuva‐maré para a
BaciadoRioSantoAntônioemCaraguatatuba(SP).São
Paulo, 2013. Dissertação (Mestrado apresentado ao
DepartamentodeEngenharia
Hidráulica e Sanitáriada
EscolaPolitécnicadaUniversidadedeSãoPaulo).
DEFRA – Department for Environment, Food & Rural
Affairs of the UK Government, 2010. Defra’s Climate
Change Plan 2010.
https://www.gov.uk/government/uploads/system/uploa
ds/attachment_data/file/69254/pb13358‐climate‐change‐
plan‐2010‐100324.pdf
FEMAR – Fundação de Estudos do Mar, 2000. Catálogo de
EstaçõesMaregráficasBrasileiras.
RiodeJaneiro.
Franco, A. S., 2009. Marés: Fundamentos, Análise e Previsão.
Niteroi,DiretoriadeHidrografiaeNavegação,Niteroi.
IPCC, 2013. Summary for Policymakers. Climate Change 2013:
ThePhysicalScienceBasis.ContributionofWorkingGroupI
totheFifthAssessmentReportoftheIntergovernmentalPanel
on Climate Change. Cambridge University
Press,
Cambridge,UnitedKingdomandNewYork,NY,USA.
Nicholls, R.J.; Hanson, S., Herweijer, C., Patmore, N.,
Hallegatte, S., Corfee‐Morlot, J., Château, J. and Muir‐
Wood, R., 2008. Ranking Port Cities with High Exposure
and Vulnerability to Climate Extremes: Exposure Estimates.
Paris: OECD Publishing, OECD Environment Working
Papers1,
63p.http://dx.doi.org/10.1787/011766488208
PIANC–TheWorldAssociationforWaterborneTransport
Infrastructure,2014.Countries in Transition(CIT) Coastal
Erosion Mitigation Guidelines. Brussels, Belgium:
CooperationCommission(CoCom),PIANCReport123.
PIANC–TheWorldAssociationforWaterborneTransport
Infrastructure, 2014. Sustainable Ports, A Guide for Port
Authorities. Brussels, Belgium: IAPH EnviCom
Report
WorkingGroup150,PIANCReport150.
Rahmstorf, S., 2007. A semi‐empirical approach to
projectingfuturesea‐levelrise.Science,315,368‐370.
