sus ainabili y
A icle
Socio-Economic Assessmen o G een In as uc u e
o Clima e Change Adap a ion in he Con ex o
U ban D ainage Planning
Luca Loca elli 1,* , Ma ia Gue e o 2, Beniamino Russo 1, Edua do Ma ínez-Goma iz 2,3 ,
Da id Sunye 1and Mon se Ma ínez 1
1AQUATEC—Suez Ad anced Solu ions, Ps. Zona F anca 46-48, 08038 Ba celona, Spain;
[email p o ec ed] (B.R.); [email p o ec ed] (D.S.); [email p o ec ed] (M.M.)
2
Ce aqua, Wa e Technology Cen e, Ca e e a d’Esplugues, 75, 08940 Co nell
à
de Llob ega , Ba celona, Spain;
ma ia.gue e [email p o ec ed] (M.G.); edua [email p o ec ed] (E.M.-G.)
3Flumen Resea ch Ins i u e, Uni e si a Poli ècnica de Ca alunya, Jo di Gi ona 1-3, 08034 Ba celona, Spain
*Co espondence: [email p o ec ed]
Recei ed: 21 Ma ch 2020; Accep ed: 29 Ap il 2020; Published: 7 May 2020


Abs ac :
G een in as uc u e (GI) con ibu es o imp o e u ban d ainage and also has o he socie al
and en i onmen al bene i s ha g ey in as uc u e usually does no ha e. Economic assessmen o
u ban d ainage planning and decision making o en ocuses on lood c i e ia. This s udy p esen s an
economic assessmen o GI based on a con en ional cos -bene i analysis (CBA) ha includes se e al
bene i s ela ed o u ban d ainage ( loods, combined sewe o e lows and was e wa e ea men ),
en i onmen al impac s ( ecei ing wa e bodies) and addi ional socie al and en i onmen al bene i s
associa ed wi h GI (ai quali y imp o emen s, aes he ic alues, e c.). Bene i s om lood damage
educ ion a e mone ized based on he widely used concep o Expec ed Annual Damage (EAD) ha
was calcula ed using a 1D/2D u ban d ainage model oge he wi h design s o ms and a damage
model based on ailo ed lood dep h–damage cu es. Bene i s om Combined Sewe O e lows
(CSO) damage educ ion we e mone ized using a 1D u ban d ainage model wi h con inuous ain all
simula ions and p ices pe cubic me e o spilled combined sewage wa e es ima ed om li e a u e;
o he socie al bene i s we e es ima ed using uni p ices also es ima ed om li e a u e. This economic
assessmen was applied o wo di e en case s udies: he Spanish ci ies o Ba celona and Badalona.
The esul s a e use ul o decision making and also unde line he ele ancy o including no only
lood damages in CBA o GI.
Keywo ds: u ban lood; wa e quali y; cos -bene i analysis; modelling; combined sewe o e lows
1. In oduc ion
G een in as uc u e (GI)—also ecognized wi h he ac onyms NBS (Na u e-Based Solu ions),
SUDS (Sus ainable U ban D ainage Sys ems), LID (Low Impac De elopmen ), BMP (Bes Managemen
P ac ices), WSUD (Wa e Sensi i e U ban Design) and many o he s [
1
]—con ibu es o imp o e
u ban s o mwa e managemen and has se e al o he socie al bene i s like ai quali y imp o emen s,
educ ion o hea island e ec s, aes he ic and ec ea ional alues, and o he s [
2
]. Socio-economic
assessmen o GI is an impo an ool o u ban d ainage planning and decision making o clima e
change adap a ion s a egies [3].
Se e al s udies ha e p esen ed socio-economic assessmen s o di e en clima e change adap a ion
op ions ocusing on di ec and indi ec bene i s de i ed om lood damage educ ion capaci y o GI.
Velasco e al. [
4
] p esen ed a cos -bene i analysis whe e only di ec bene i s we e included in e ms o
a oided lood damages ob ained by di e en adap a ion scena ios in Ba celona: s uc u al measu es
Sus ainabili y 2020,12, 3792; doi:10.3390/su12093792 www.mdpi.com/jou nal/sus ainabili y
Sus ainabili y 2020,12, 3792 2 o 18
(pipe enla gemen and s o mwa e anks), GI, lood ba ie s o g ound loo doo s o businesses
and p i a e buildings and ea ly-wa ning sys ems. Zhou e al. [
3
,
5
] p esen ed a amewo k and i s
applica ion o a Danish case s udy o economic assessmen o di e en clima e adap a ion op ions
ocusing on lood impac s. The economical assessmen was based on a cos -bene i analysis (CBA) wi h
di ec and indi ec bene i s de i ed om lood damage educ ion ha we e mone ized using lood
models oge he wi h damage cos s o houses, basemen s, sewe s, oads, lakes and people heal h and
also adminis a i e and a ic delay cos s. The damage cos s we e calcula ed using uni cos s epo ed
om case-speci ic li e a u e. In hese pape s, lood adap a ion op ions based on pipe enla gemen s
we e compa ed o s o mwa e in il a ion h ough GI ocusing on lood educ ion bene i s.
Fu he s udies p esen socio-economic assessmen s including addi ional bene i s no only ela ed
o di ec o indi ec lood damages [
6
]. Löwe e al. [
7
] p esen ed a cos -bene i analysis (CBA) o
compa ing di e en lood adap a ion op ions in Aus alia. The lood adap a ion op ions consis ing
o pipe enla gemen , lood zoning and ainwa e ha es ing h ough GI we e compa ed including
lood educ ion bene i s and also addi ional bene i s de i ed om educ ion o d inking wa e
consump ion. Zhou e al. [
8
] p esen ed an in eg a ed hyd ological cos -bene i analysis o compa ison
o di e en clima e adap a ion op ions such as open u ban d ainage sys ems, pipe enla gemen and
local s o mwa e in il a ion. He e, bene i s de i ed om lood damage educ ion we e in eg a ed
wi h addi ional mone ized bene i s de i ed om inc eased p ope y alues in he a eas whe e GI was
planned and he consequen inc ease in p ope y axes. Finally, Coope e al. [
9
] p esen ed an in eg a ed
cos s-bene i s analysis o a be m (sea wall) o mi iga e he e ec s o coas al looding om sea s o ms.
He e, he mone ized bene i s o he p ojec included: a oided cos s de i ed om building damages,
managemen expenses, a ali ies, deb is emo al, u ili y and municipal damages; bene i s de i ed
om ec ea ional and heal h alue and indi ec cos s de i ed om in e up ion o key anspo a ion
and comme cial in as uc u e loca ed in he a ea. The ec ea ional and heal h alues we e linked o
he ecosys em se ices and heal h bene i s o he su ounding communi y gene a ed by he planned
g een a eas along he be m.
Fu he s udies unde lined he impo ance o analyzing GI wi h a mul idisciplina y app oach.
Venka a amanan e al. [
10
] p esen ed a mul idisciplina y li e a u e e iew ocusing on he in e ac ion
be ween human dimensions and socio-ecological- echnical sys ems ha a e in ol ed wi h GI in he
con ex o lood isk managemen . Addi ionally, Wilke son e al. [
11
] analyzed he ole o socio-economic
ac o s in ol ed in he planning and managemen o u ban ecosys em se ices.
The aim o his pape is o p esen a cos -bene i analysis ha includes mul iple bene i s de i ed
om g een in as uc u e in he con ex o u ban d ainage planning. The no el y o his s udy is he
in eg a ion o wa e quan i y and quali y and o he socio-economic bene i s in o CBA o GI in he
con ex o u ban d ainage planning. The applica ion o his analysis o wo di e en case s udies can
also be conside ed as no el since he applica ion o CBA is gene ally used o compa ing di e en
adap a ion measu es wi hin he case s udy. GI bene i s a e calcula ed om di ec and indi ec lood
impac s educ ion, wa e quali y ela ed bene i s and addi ional socie al bene i s. Bene i s o lood
damage educ ion a e calcula ed as a oided di ec and indi ec lood damage cos s o buildings,
ehicles, u ban in as uc u e and indi ec cos s. Flood damage cos s a e calcula ed using coupled 1D
u ban d ainage and 2D su ace uno models oge he wi h ailo ed dep h–damage and pe meabili y
coe icien s unc ions. Wa e quali y ela ed bene i s de i ed om CSO and was e wa e ea men
cos educ ion a e calcula ed using a 1D u ban d ainage model and cos s o was ewa e ea men
and CSO spills ob ained om li e a u e. Finally, addi ional socie al bene i s like inc eased aes he ic
alue, ai quali y imp o emen , habi a p o ision and educed u ban hea island e ec and ene gy
consump ion, a e calcula ed based on uni cos s om li e a u e. The socio-economic assessmen is
applied o wo di e en case s udies: he Spanish municipali ies o Ba celona and Badalona. These wo
case s udies we e pa o he wo Eu opean H2020 esea ch p ojec s: BINGO (B inging Inno a ion o
onGOing wa e managemen . www.p ojec bingo.eu) and RESCCUE (Resilience o Cope wi h Clima e
Change in U ban A eas. www. esccue.eu). The aim o p esen ing wo cases is mainly o show ha
Sus ainabili y 2020,12, 3792 3 o 18
he me hodology can be applied o di e en cases. Ne e heless, he compa ison can also b ing new
poin s o iew in he discussion o GI in he con ex o u ban d ainage planning. The me hodology
p oposed can be conside ed gene ally applicable o o he ci ies in he con ex o g een in as uc u e
and u ban d ainage planning.
2. Ma e ials and Me hods
2.1. The Two Case S udies
2.1.1. The Case S udy o Ba celona
Ba celona (Figu e 1) has an ex ension o app oxima ely 100 km
2
, 1,619,000 inhabi an s and i is
highly u banized. An impo an pa o i s u ban de elopmen lies in a la a ea up o ew ens o
me e s abo e mean sea le el. The ci y aces he Medi e anean Sea and app oxima ely hal o i s coas
line is occupied by he ha bo and he emaining by sandy beaches. In he opposi e side o he sea,
he e a e hills wi h signi ican slopes owa ds he u ban a ea. The g ea majo i y o he d ainage sys em
is a combined one and Ba celona expe iences u ban plu ial loods due o in ense ain alls, s eep slopes
owa ds he la u ban a ea, high deg ee o impe iousness and, in ecen yea s, expansion o new
u ban a eas d aining in o an olde d ainage sys em. The mean annual ain all is 612 mm/y, he deg ee
o impe iousness is es ima ed o be app oxima ely 70% o he whole municipal a ea e en hough
i can each much highe pe cen ages in he u ban a eas (see o ins ance he wo zoom-in a eas in
Figu e 1). The ci y also expe iences Combined Sewe O e lows (CSO) ha gene ally occu du ing
ain all e en s la ge han a ew millime e s. CSOs pollu e he i e Besos ( ha coincides wi h he
no h-eas e n bounda y o he municipal a ea shown in Figu e 1) and he sea wa e bo h in on o he
beaches and in he ha bo . Figu e 1also shows he planned GI ha will be desc ibed in Sec ion 2.2.1.
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0 1,5 3 km
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!
!
0 0,25 0,5 km
Municipal bounda y
!
!De en ion and e en ion ponds
"G een oo s
Bio e en ion cells on di e en oads:
9-15 m wide and 0-2.5% slope
9-15 m wide and 2.5-6% slope
15-40 m wide and 0-2.5% slope
15-40 m wide and 2.5-6% slope
>40 m wide and 0-2.5% slope
Figu e 1.
Plan iew o Ba celona wi h all he planned GI: ponds, g een oo s and bio e en ion cells.
The colo ed lines show he classi ica ion o i e di e en kind o s ee s whe e bio e en ion cells a e
planned (a di e en spa ial alloca ion o bio e en ion cells was p oposed as a unc ion o he di e en
s ee slope and wid h).
Sus ainabili y 2020,12, 3792 4 o 18
2.1.2. The Case S udy o Badalona
Badalona (Figu e 2), wi hin he Ba celona Me opoli an A ea, has an ex ension o app oxima ely
21 km
2
, 215,000 inhabi an s ( he ou h mos popula ed ci y in Ca alonia) and i is highly u banized.
An impo an pa o i s u ban de elopmen lies in a la a ea up o ew ens o me e s abo e mean sea
le el. In he no h and no h-wes e n pa o he municipali y he e a e hills wi h signi ican slopes
owa ds he u ban a ea. On he opposi e side he ci y has app oxima ely 5 km o sandy beaches acing
he Medi e anean Sea. Badalona expe iences u ban plu ial loods due o in ense ain alls, s eep slopes
owa ds he la u ban a eas, high deg ee o impe iousness and, in ecen yea s, expansion o new
u ban a eas d aining in o an olde d ainage sys em. The mean annual ain all is 568 mm/y, he deg ee
o impe iousness is es ima ed o be app oxima ely 57% o he whole municipal a ea e en hough
i can each much highe pe cen ages in he u ban a eas (see o ins ance he wo zoom-in a eas in
Figu e 2). Almos all he d ainage sys em is a combined one and CSOs ha gene ally occu du ing
ain all e en s la ge han a ew millime e s pollu e he sea wa e . Figu e 2also shows he planned GI
ha will be desc ibed in Sec ion 2.2.3.
In il a ion enches
Pe meable pa emen s
Municipal bounda y
012 km
N
Figu e 2.
Plan iew o Badalona wi h he planned g een in as uc u e (g een oo s a e no shown) and
wo zoom-in a eas o be e isualiza ion o he u ban en i onmen .
2.2. The Clima e Change Adap a ion Scena ios
G een in as uc u e was one ou o he se e al clima e change adap a ion op ions (do no hing,
pipe enla gemen , new pipes and de en ion s o ages and ea ly-wa ning sys ems) p oposed and
analyzed in ag eemen wi h he di e en local s akeholde s. In his s udy, wo di e en adap a ion
scena ios wi h u u e ain alls a e p esen ed: he business as usual (BAU) scena io whe e no adap a ion
Sus ainabili y 2020,12, 3792 5 o 18
is conside ed, and he GI scena io. The BAU scena io is used as a e e ence scena io when calcula ing
bene i s as pa o he cos -bene i analysis. Bo h BAU and GI scena ios we e based on u u e simula ed
ain alls. Two kinds o u u e ain alls we e es ima ed o each o he wo case s udies: a u u e design
s o m e en ele an o single e en lood simula ions and a u u e con inuous ain all ime se ies
ele an o con inuous u ban wa e simula ions ha aimed a s imula ing combined sewe o e lows,
wa e quali y impac s on he Medi e anean Sea and annual combined sewe wa e luxes a was e
wa e ea men plan s. The u u e design s o m e en s we e calcula ed by applying clima e ac o s (CF)
o cu en design s o m e en s acco ding o A nbje g-Nielsen e al. [
12
]. I is no ed ha signi ican ly
di e en app oaches we e used in Ba celona and Badalona in o de o de i e CF. In Ba celona he 50 h
pe cen iles o all Rep esen a i e Concen a ion Pa hways (RCP) 8.5 and 4.5 scena ios we e used o
compu e CF as a unc ion o bo h di e en e u n pe iods and ain all du a ions. Ins ead, in Badalona
he a e age alues o RCP 8.5 we e used o compu e CF as a unc ion o di e en e u n pe iods.
Ne e heless, he ob ained clima e alues a e in bo h cases wi hin he ange p oposed in o he local
s udies [
13
]. De ails on he de i a ion o CF and u u e ain all ime se ies a e p o ided in he ollowing.
Fu he u u e clima e a iables like empe a u e, sea le el ise, wind, sola adia ion, e c., we e no
conside ed in he cu en clima e change adap a ion scena ios e en hough hey likely impac he
u u e u ban d ainage sys ems and GI pe o mances [14].
2.2.1. G een In as uc u e in Ba celona
The p oposed GI in Ba celona was ag eed wi h local p ojec s akeholde s and i was mos ly de i ed
om a s udy o he Municipali y o Ba celona [
15
] ha aimed a inc easing s o mwa e exploi a ion in
he ci y. Th ee di e en ypes o GI we e p oposed: g een oo s, bio e en ion cells and e en ion and
de en ion basins. Figu e 1shows he loca ion o GI h oughou Ba celona. Ex ensi e g een oo s a e
assumed o be e o i ed o app oxima ely 5% (143 ha) o all he oo a ea o Ba celona. This pe cen age
was de i ed om a s udy o he Municipali y o Ba celona [
16
] ha analyzed he oo a eas sui able o
g een oo e o i ing. Bio e en ion cells wi h a o al a ea o app oxima ely 181 ha a e supposed o be
implemen ed in almos all he s ee s o Ba celona as shown in Figu e 1. The loca ion and p elimina y
design o hese bio e en ion sys ems we e p oposed in a s udy o he Municipali y o Ba celona [
15
]
ha sugges ed i e di e en spa ial dis ibu ion and capaci y o bio e en ion sys ems depending on
s ee slope and wid h ( he i e s ee ypes classi ied we e p esen ed in Figu e 1). The p oposed
sys ems a e made o a op soil and ege a ion laye and a deepe laye o mo e po ous ma e ial
o wa e de en ion and in il a ion in o he unde lying soil. The bio e en ion cells a e de ised o
managing s o mwa e uno om pa o he whole s ee s whe e hey a e buil . Finally, en e en ion
and de en ion basins wi h a o al olume o 128,700 m
3
a e supposed o be loca ed a he ups eam
pa s o he u ban a ea in o de o collec s o mwa e uno om he ups eam u al a eas o a 10-yea
e u n pe iod design s o m. App oxima ely hal o he basin olume is alloca ed o e en ion wi h
in il a ion in o he g ound and he es o de en ion and educ ion o peak s o mwa e uno . O he
examples o he combina ion o e en ion and de en ion olumes can be ound in he li e a u e [17].
O e all, he GI implemen a ion in Ba celona would educe he o al impe ious a ea by
app oxima ely 14% o all he modelled a ea. Ne e heless, his educ ion is highe in he ci y
cen e eaching app oxima ely 29%. I is no ed ha bio e en ion cells and e en ion and de en ion
basins do manage s o mwa e uno om hei associa ed ca chmen a eas (la ge a eas compa ed o
hei physical cons uc ion a eas).
2.2.2. The Fu u e Rain alls in Ba celona
The u u e ain alls in Ba celona we e compu ed based on he esul s o CMIP5 clima e models
conside ing he RCP scena ios 8.5 and 4.5. Downscaling me hods we e hen applied and e i ied
using bo h he ERA-In e im e-analysis as a e e ence o ep oducing he pas clima e a iables and
o he s a is ical indica o s. Fu u e ain alls we e inally de i ed using bo h ain all obse a ions om
local ain gauges and di e en a mosphe ic ci cula ion models: ACCESS1, BCC-CSM1, CanESM2,

Sus ainabili y 2020,12, 3792 6 o 18
CNRM-CM5, GFDL-ESM2M, HADGEM2-CC, MIROC-ESM-CHEM, MPI-ESM-MR, MRI-CGCM3 and
No ESM1. Each model p o ided pas (1951–2005) and u u e (2021–2100) ain all ime se ies.
The CF used o lood simula ions we e compu ed o bo h di e en ain all du a ions (5, 10,
15 min, e c.) and di e en e u n pe iods (T =1, 10, 50, 100 and 500 y) by calcula ing he ain all
in ensi y a io be ween he simula ed u u e (2071–2010) and simula ed his o ical pe iod (1976–2005).
The compu ed CF we e in he ange be ween 1.07 and 1.26 and co esponded o he 50
h
pe cen ile o
he p edic ed RCP 8.5 and 4.5 scena ios.
The u u e ain all ime se ies used o con inuous u ban wa e simula ions was selec ed o be
he same as he ac ual one. This choice came a e analyzing he p edic ed u u e ain all olume
and annual numbe o ain all e en s. The 50
h
pe cen ile o he la e wo a iables did no show an
inc ease in he u u e and he e o e, oge he wi h he p ojec s akeholde s, i was decided o keep
he cu en ain all ime se ies o con inuous u ban wa e simula ions o he u u e clima e change
adap a ion scena ios.
2.2.3. G een In as uc u e in Badalona
The p oposed GI in Badalona was ag eed oge he wi h local p ojec s akeholde s ha spo ed
ealis ic nea - u u e implemen a ion a eas. Th ee di e en ypes o GI we e selec ed o he adap a ion
scena io: g een oo s, pe meable pa emen s and in il a ion enches (Figu e 2). Ex ensi e g een oo s
a e assumed o be e o i ed o 5% o all he oo a ea o Badalona. Pe meable pa emen s wi h a o al
a ea o 47,000 m
2
a e supposed o be implemen ed in 7 di e en public squa es and pa ks. In il a ion
enches a e supposed o be implemen ed in 5 di e en public pa ks ha ha e a o al a ea o 298,372 m
2
.
These enches a e supposed o e ain and in il a e in o he g ound bo h he impe ious and pe ious
s o mwa e uno om he pa ks (mos ly pe ious a eas) gene a ed by a design s o m o 10 yea s
e u n pe iod. A o al ench olume o 1923 m
3
was es ima ed (assuming a 95% po osi y o he ench
illing ma e ial).
O e all, he planned GI implemen a ion in Badalona would educe he o al impe ious a ea by
app oxima ely 2%. I is no ed ha in il a ion enches do no educe impe ious a eas; howe e , hey
do manage s o mwa e uno om hei associa ed ca chmen a eas.
2.2.4. The Fu u e Rain alls in Badalona
Two di e en sou ces o u u e clima e da a we e used in he case o Badalona. The u u e
design s o m e en s o lood simula ions we e ob ained om clima e p ojec ions esul s o he
EURO-CORDEX p ojec (www.eu o-co dex.ne ) while he u u e ain all ime se ies o con inuous
u ban wa e simula ions we e ob ained om he decadal clima e p edic ions o he Miklip p ojec
(www. ona-miklip.de) ha we e de i ed om he model MPI-ESM (www.mpime .mpg.de/en/science/
models/mpi-esm/).
The CF used o lood simula ions we e ob ained by calcula ing he 24 h ain all in ensi y a io
be ween u u e p ojec ions (2051–2100) and his o ical simula ed ain all (1951–2005). Th ee di e en
RCP scena ios we e analyzed: 8.5, 4.5 and 2.6. The CF ob ained wi h a e age ain all in ensi ies om
RCP 8.5 scena ios we e he ones selec ed oge he wi h he p ojec s akeholde s o lood simula ions.
A CF o 1.15 o he 2-yea e u n pe iod design s o m was ob ained, 1.07 o he 10-yea , 1.02 o
he 100-yea and 1.01 o he 500-yea . In his case, he same clima e ac o is applied o all ain all
du a ions. Calcula ing clima e ac o s om 24 h ain all in ensi y a io can be a limi a ion [18].
The u u e ain all ime se ies used o con inuous u ban wa e simula ions we e ob ained in wo
s eps: i s , he daily ain all was ob ained using he Daily Spa io-Tempo al S ochas ic P ecipi a ion
Gene a o [
19
]; hen, disagg ega ion o daily ain all in o 5 min alues was made using a s ochas ic
me hod ha combined bo h he Ba le –Lewis p ocess [
20
] and u he p ocedu es (included in o
he R package ‘Hye osMinu e’) in o de o ep oduce he 5 min ain all obse a ions om local ain
gauges. This p ocedu e p o ided an ensemble o 10 di e en ime se ies wi h bo h his o ical and u u e
ain all. Only a single ime se ies ep esen ing a e age u u e ain all condi ions was selec ed and
Sus ainabili y 2020,12, 3792 7 o 18
used o con inuous simula ions wi h he u ban d ainage and he sea wa e quali y model (p esen ed
in Sec ion 2.3.2).
2.3. The Cos -Bene i Analysis
2.3.1. Cos s
The capi al (CAPEX) and ope a ion and main enance (OPEX) cos s o he planned g een
in as uc u e a e based on uni cos s ob ained om bo h li e a u e and local expe ience. The cos s
anges ound in p o ide websi es, unpublished documen s and li e a u e ha e gene ally a la ge
sp ead. In his cos -bene i analysis (CBA) he cos s we e de i ed pa ly om li e a u e [
21
] and pa ly
om unpublished documen s and in e nal esea ch p ojec s. The di e en cos s we e con e ed in o
he same yea alue using consume p ice indices. The CAPEX o ex ensi e g een oo s a e assumed o
be 80
€
/m
2
and he OPEX 2.33
€
/m
2
/y. Bianchini e al. [
22
] epo ed a CAPEX ange o 120–152
€
/m
2
and an OPEX one o 1–12
€
/m
2
o ex ensi e g een oo s. The CAPEX o bio e en ion cells a e 45
€
/m
2
plus 2.25
€
/m
2
o plan implemen a ion and he OPEX 0.45
€
/m
3
/y. The CAPEX o de en ion and
e en ion ponds a e 100
€
/m
2
and he annual OPEX is 1.49% o he CAPEX. The CAPEX o pe meable
pa emen s a e 49.5
€
/m
2
and he OPEX 1.375
€
/m
3
/y. The CAPEX o in il a ion enches a e assumed o
be 185
€
/m
3
and addi ional 742
€
/m
3
he OPEX 50
€
/m
3
/y. The addi ional CAPEX o in il a ion enches
in his case include he cos s o addi ional manholes, inle s and pipes ha need o be cons uc ed
since hese sys ems a e supposed o be cons uc ed in o a public pa k a ea whe e exis ing d ainage
connec ions a e limi ed. The es ima ed CAPEX o he in il a ion enches p oposed in Badalona a e
simila o he cos s paid by he municipali y o an execu ed p ojec . Zhou e al. [
8
,
23
] used in es men
cos s o in il a ion enches in he ange be ween 16 and 91
€
/m
2
. Al es e al. [
6
] es ima ed annual
OPEX as 3% o CAPEX cos s.
The li e ime o an in as uc u e can a y depending on I s main enance: he highe he
main enance cos s he longe he li e ime [
24
]. In Badalona ex ao dina y main enance was assumed o
be ca ied ou e e y 20 yea s wi h a cos equal o he 23% o he CAPEX a each in e en ion. Simila ly,
in Ba celona i was assumed e e y 20 yea s o bio e en ion cells and 50 yea s o g een oo s and
e en ion and de en ion ponds wi h a cos equal o he 50% o he CAPEX a each in e en ion.
Residual GI alue a he end o he p ojec e alua ion pe iod was also conside ed acco ding o
Eu opean ecommenda ions o e alua ions o in es men s [
25
]. This e lec s he alue o he emaining
po en ial use o GI since i s se ices will be p o ided u he beyond he end o he CBA e alua ion
pe iod [
25
]. In his s udy, i was conside ed as a nega i e cos bu i could also be conside ed as a
bene i as he choice does no a ec he ne p esen alue Equa ion (1) (i only a ec s he g aphical
p esen a ion o cos and bene i s).
2.3.2. Bene i s
Se e al bene i s can be included in o CBA o g een in as uc u e [
5
,
9
,
14
]. Bene i s can be di ec
and indi ec , angible (i.e., ha can be quan i ied in mone a y alues) and in angibles [
26
]. In his s udy,
di ec and indi ec angible bene i s a e aken in o conside a ion. The bene i s o he GI scena io we e
calcula ed as a oided damages (o added alues) compa ed o he BAU scena io ha is conside ed o
be he e e ence as ypically done in simila CBA [
3
,
5
]. In his s udy, he bene i s we e o ganized in o 3
di e en ca ego ies o a be e ep esen a ion and discussion o he esul s:
•
Bene i s de i ed om lood damage educ ion. Bene i s a e de ined as a oided di ec and indi ec
lood damage cos s. Flood damage cos s we e quan i ied in e ms o Expec ed Annual Damage
(EAD) using a 1D/2D u ban d ainage model oge he wi h design s o ms and a damage model
based on ailo ed lood dep h–damage cu es [
27
]. The di ec lood damages we e quan i ied o
in as uc u e, ehicles, buildings and asse s, while he indi ec damages o business in e up ion.
•
Bene i s de i ed om wa e quali y imp o emen s. Bene i s a e de ined as a oided di ec and
indi ec damage cos s. The di ec damages a e quan i ied as en i onmen al cos s p oduced by
Sus ainabili y 2020,12, 3792 8 o 18
CSO spills o ecei ing wa e bodies and o a oided cos s o combined sewage ea men . Indi ec
damages a e mone ized o coas al economies ha a e a ec ed by he pollu ed wa e .
•
Addi ional bene i s. Addi ional indi ec bene i s a e mone ized conside ing: inc eased aes he ic
alue, ai quali y imp o emen , educ ion o he u ban hea island e ec and ene gy consump ion,
and habi a p o ision [22,24].
Di ec lood damages in bo h Ba celona and Badalona we e quan i ied using coupled 1D/2D
(u ban d ainage/o e land low) models and damage models based on ailo ed lood damage cu es
(de eloped o indoo lood wa e le els) and pe meabili y coe icien cu es ha we e de eloped
oge he wi h lood insu ance expe s [
27
]. The damage model akes as inpu s he de e minis ic and
spa ially dis ibu ed alues o maximum lood dep h simula ed wi h he 1D/2D u ban d ainage model.
The simula ed lood dep h om he 1D/2D model (conside ed as ou doo lood dep h) is con e ed
in o building indoo wa e le els using he pe meabili y coe icien cu es and hen he lood damage
cu es a e applied o indoo wa e le els. In he case o buildings wi h basemen s u he model
pa ame e s con ol he indoo lood wa e exchange om g ound loo o lowe loo s. Bo h he lood
models and he damage models (o Ba celona and Badalona) we e calib a ed and alida ed using
his o ical da a. The lood models used wa e le el da a in he d ainage ne wo k, ain gauge da a and
pho os o u ban loods du ing di e en pas ain e en s. The damage models used lood insu ance
compensa ion da a om di e en lood e en s du ing he las ew decades [
27
]. The mos in luen ial
model pa ame e s o he 1D/2D model we e he oughness coe icien s o pipes and u ban su aces and
o he damage model he pa ame e s con olling he indoo lood wa e le el exchange om g ound
loo o lowe loo s [27].
The 1D/2D model p o ides he maximum simula ed lood dep h o di e en design s o ms o
di e en e u n pe iods be ween 1 and 500 yea s: 1, 10, 50, 100 and 500 yea s o Ba celona and 2, 10,
100 and 500 o Badalona. Fo each e u n pe iod, he o al lood damages a he u ban scale we e
calcula ed by mul iplying he maximum simula ed lood dep h a each cadas al pa cel by pe meabili y
coe icien s and lood dep h–damage cu es ha we e speci ically ailo ed o Badalona and Ba celona
o di e en land uses (ho els, wa ehouses, es au an s, dwellings, ca pa ks, e c.) and ehicles [
28
].
The pe meabili y coe icien cu es we e used o ans o m he 2D simula ed lood le els on he u ban
loodable a ea in o indoo wa e le els. Finally, Expec ed Annual Damage (EAD) was calcula ed
including bo h di ec and indi ec damages as de ailed in a p e ious s udy o Badalona [
27
]. Indi ec
lood damages due o business in e up ions we e es ima ed a 29% o he o al di ec damages using an
inpu –ou pu model [
27
]. This pe cen age is in he ange o o he s udies ha p oposed 19–39% [
29
,
30
].
The 1D/2D hyd odynamic models we e de eloped wi h In oWo ks ICM (www.inno yze.com)
and calib a ed and alida ed using local ain all and wa e le el da a. The 1D sewe model o Badalona
includes app oxima ely 368 km o pipes, 11,338 manholes, 11,954 sub-ca chmen s, 62 wei s, 4 sluice
ga es, and 1 de en ion ank o 30,000 m
3
. The 2D model has 199,338 cells ha o m an uns uc u ed
mesh gene a ed om a digi al e ain model (DTM) o 2 m
2
esolu ion ob ained by a LIDAR wi h a
p ecision o app oxima ely 15 cm o he al i udes. The size o he 2D cells is in he ange o 16–64 m
2
in he u ban a eas whe e mos o he lood damages occu . The 1D sewe model o Ba celona includes
app oxima ely 2041 km o pipes, 85,834 manholes, 980 wei s, 44 sluice ga es, 75 pumps and 285 s o age
nodes ep esen ing di e en kinds o chambe s and 10 de en ion anks wi h a o al olume o mo e
han 400,000 m
3
. The 2D model has 1,361,324 cells ha o m an uns uc u ed mesh gene a ed om a
digi al e ain model (DTM) o 2 m
2
esolu ion ob ained om a LIDAR. The size o he 2D cells is in
he ange o 25–100 m2.
Di ec and indi ec wa e quali y bene i s we e compu ed using con inuous simula ion o a 1D
u ban d ainage model o es ima e annual olumes o CSO and combined sewage wa e sen a he
ea men plan . The u ban d ainage models used we e he 1D/2D models p esen ed ea lie bu wi hou
he 2D o e land low model. The u ban d ainage models we e hen coupled o a sea wa e quali y
model [
31
] o simula e he sea wa e con amina ion om CSOs and o es ima e he a e age du a ion
o insu icien ba hing wa e quali y. The du a ion o insu icien ba hing wa e quali y was used as
Sus ainabili y 2020,12, 3792 9 o 18
an inpu o a coas al economy model ha es ima es indi ec damages o coas al economies caused by
pollu ion o ba hing wa e s and he consequen educ ion o sea ela ed leisu e, spo and es o a ion
ac i i ies. The coas al economy model includes di e en con ibu ions. Fi s , he daily di ec added
alue o he coas al economy was calcula ed by selec ing he expec ed business sec o s a ec ed by a
beach closu e ( es au an s, small e ails and ma i ime sec o ). This selec ion was based on he esul s
o a ield s udy based on su eys o beach goe s and pe sonal in e iews o coas al business owne s
ca ied ou in Ba celona and Badalona (see bo h H2020 BINGO and RESCCUE p ojec s). Second, based
on da a om Ba celona’s economic annual epo [
32
] a 50% sha e o he annual coas al economic
added alue was assumed o come om he ba hing season [
33
], which las s app oxima ely 3–4 mon hs
in Badalona and Ba celona. Only he di ec added alue o coas al dis ic s (iden i ied by compa ing
he CSO spill poin s wi h he dis ic s maps) a ec ed by CSO spills we e included. Fu he mo e,
assump ions o he magni ude o he impac pe sec o we e made based on he esul s o he local
su eys: 50% impac o es au an s, 25% o e ails and 25% o ma i ime sec o (wa e spo and p i a e
ishing). The daily economic impac ob ained by di iding he alue added by he numbe o days o
he ba hing season, was inally mul iplied by he a e age numbe o sea wa e pollu ion days (whe e
he beaches could po en ially be closed o ba hing) o es ima e he po en ial annual indi ec damages
o he coas al economy.
The di e en GI sys ems we e simula ed in bo h he 1D and he 1D/2D d ainage models by
con e ing he planned GI a eas om impe ious a eas in o pe ious a eas wi h hyd ological losses.
This simpli ied app oach was also used by Velasco e al. [
4
]. Howe e , o he knowledge o he au ho s,
his me hod was no alida ed wi h hyd ological da a and can be a limi a ion.
The di ec damages p oduced by CSO spills o ecei ing wa e bodies we e calcula ed using a
epa a ion cos me hod, which assumes ha he alue o he damage is equal o he cos o epai ing
i [
34
]. The di ec damage p oduced by CSO spills was ob ained mul iplying he a e age annual
CSO olume by he uni CSO damage cos o 0.7
€
/m
3
in Badalona. Ins ead, in he case o Ba celona
di e en alues we e used: 2.69
€
/m
3
o CSOs o he sea and 1.50
€
/m
3
o he i e and he ha bo
acco ding o a Spanish egional no ma i e de ised o indus ial spills [
35
]. Ano he bene i conside ed
was he educ ion o he sewage wa e o be ea ed by he was ewa e ea men plan s (WWTPs).
The mone iza ion o his bene i was calcula ed as he a oided cos s o combined sewe wa e ea men
ha we e es ima ed by mul iplying he a e age ea ed annual olumes om he u ban d ainage
model wi h a selec ed uni ea men cos o 0.12
€
/m
3
ha is conside ed easonable o local WWTPs
based on local expe ise. The angible indi ec damages (and he consequen bene i s calcula ed as
a oided damages) o coas al economies we e es ima ed using he pollu ion ime om he sea wa e
quali y model and he coas al economy model explained be o e.
The addi ional indi ec bene i s conside ed a e based on ou con ibu ions. The i s is aes he ic
alue which is mone ized as he willingness o pay o p ope ies nea by, o ha include g een
in as uc u e, is measu ed h ough he inc ease o he alue o hese p ope ies. This alue could also
include he inc eased p ope y axes acqui ed by he axa ion au ho i ies [
8
]. In his case, he bene i s
we e es ima ed wi h a bene i ans e me hod o be he 3% o he CAPEX o GI [
22
]. The bene i s
de i ed om he educ ion o ene ge ic consump ion ( o indoo hea ing and cooling) and hea island
e ec a e quan i ied using 0.049
€
/m
2
/y pe g een oo uni su ace [
24
]. Bene i s de i ed om u ban
hea island educ ion ob ained wi h bio e en ion cells ( ha in Ba celona a e planned) we e no included
and his can be a limi a ion. The ai quali y bene i s a e de i ed om bo h emission educ ion (o
CO
2
and Nox) capaci y o GI ha was es ima ed o be 0.072 on/ha and he cos o emissions o
3051
€
/ on [
24
,
36
]. The habi a p o ision was based on he po en ial inc ease o u ban ecosys ems ha
suppo wildli e and i was es ima ed o be 2.8
€
/m
2
o bo h case s udies. This was es ima ed using a
bene i ans e me hod om a s udy ha assumed he alue o habi a c ea ion could be es ima ed a
15% o he alue o na u al land [22].
Sus ainabili y 2020,12, 3792 16 o 18
o he calcula ion o he a ea below he cu e ha co esponds o he EAD. The igu e shows
ha he selec ed simula ed poin s migh no be enough o p ope ly desc ibe he non-linea
ela ion be ween lood damages and exceedance p obabili y, pa icula ly o he case o Ba celona
(Figu e 3a) o he ange o exceedance p obabili y be ween 0.1 (10 yea e u n pe iod) and 1
(1 yea e u n pe iod). By in oducing new simula ion poin s ( o ins ance a 0.2 exceedance
p obabili y) he EAD ( he a ea below he cu e) migh signi ican ly educe [4,47].
E en hough he EAD is conside ed o e es ima ed and wo main di e en causes we e iden i ied,
he EADs o Ba celona we e no e-calcula ed as hese alues we e included in he la es d ainage
mas e plan o Ba celona.
5. Conclusions
This s udy p esen ed a cos -bene i analysis o e alua e he socio-economic iabili y o GI, which
was conside ed as a clima e change adap a ion op ion in he ci ies o Badalona and Ba celona. The GI
planning o he wo ci ies is signi ican ly di e en : Ba celona p oposed a widesp ead GI implemen a ion
plan while Badalona p oposed a much lowe deg ee o implemen a ion. CBA is ele an o decision
making o u ban d ainage planning and is use ul o compa ing di e en scena ios: in his case a
business as usual (BAU) and he GI scena io we e compa ed. Mul iple bene i s de i ed om GI
implemen a ion we e conside ed and hey we e g ouped in o h ee di e en ca ego ies: bene i s
de i ed om lood damage educ ion, om wa e quali y imp o emen s and om addi ional bene i s.
Fo each ca ego ies bo h di ec and indi ec angible ( ha can be mone ized) bene i s we e de ined
and quan i ied. The la ges sha e o GI bene i s in Ba celona was om educed lood damages (56%),
while in Badalona was om addi ional bene i s like added alue o p ope ies and habi a p o ision
(89%). The GI bene i s de i ed om educed sewage ea men cos s; om educed indi ec damages
o coas al economies; om ai quali y imp o emen and om educ ion o he hea island e ec and
ene gy consump ion esul ed in he ange o 0–1% playing an insigni ican ole in he socio-economic
assessmen . The calcula ed cumula i e ne p esen alue (NPV) in Ba celona became posi i e a e
10–11 yea s conside ing all bene i s, whe eas in Badalona was mos ly nega i e. O e all, his s udy
p esen ed and quan i ied how di e en mul iple bene i s ha can con ibu e o ne p esen alue as
pa o CBA. The de ails p o ided in his pape gua an ee he eplicabili y o he p esen ed CBA o
o he case s udies.
Au ho Con ibu ions:
Concep ualiza ion, L.L. and M.G.; me hodology, L.L., M.G., E.M.-G. and B.R.; so wa e,
L.L. and D.S.; alida ion, L.L. and D.S.; in es iga ion, L.L. and M.G.; esou ces, M.M.; da a cu a ion, L.L., E.M.-G.
and B.R.; w i ing—o iginal d a p epa a ion, L.L.; w i ing— e iew and edi ing, L.L., M.G., B.R. and E.M.-G.;
isualiza ion, L.L.; p ojec adminis a ion, L.L., M.M. and B.R.; unding acquisi ion, M.M. and B.R. All au ho s
ha e ead and ag eed o he published e sion o he manusc ip .
Funding:
This esea ch was unded by he BINGO Eu opean H2020 p ojec , G an Ag eemen No.641739 and he
RESCCUE Eu opean H2020 p ojec , G an Ag eemen No. 700174.
Acknowledgmen s:
The au ho s hank AMB, BCASA and he Municipali ies o Badalona and Ba celona o
hei collabo a ion.
Con lic s o In e es : The au ho s decla e no con lic o in e es .
Re e ences
1.
Fle che , T.D.; Shus e , W.; Hun , W.F.; Ashley, R.; Bu le , D.; A hu , S.; T owsdale, S.; Ba aud, S.;
Semadeni-Da ies, A.; Be and-K ajewski, J.-L.; e al. SUDS, LID, BMPs, WSUD and mo e—The e olu ion
and applica ion o e minology su ounding u ban d ainage. U ban Wa e J. 2014,9006, 1–18. [C ossRe ]
2.
Yu, H.Z. Complica ed s uc u e modeling in on -zone o Hala’ala e Moun ain o no hwes e n ma gin,
Jungga Basin. Na . Gas Geosci. 2014,25, 91–97.
3.
Zhou, Q.; Halsnæs, K.; A nbje g-Nielsen, K. Economic assessmen o clima e adap a ion op ions o u ban
d ainage design in Odense, Denma k. Wa e Sci. Technol. 2012,66, 1812–1820. [C ossRe ]

Sus ainabili y 2020,12, 3792 17 o 18
4.
Velasco, M.; Russo, B.; Cabello Te mes, M.; Sunye , D.; Malg a , P. Assessmen o he e ec i eness o
s uc u al and nons uc u al measu es o cope wi h global change impac s in Ba celona. J. Flood Risk Manag.
2018,11, S55–S68. [C ossRe ]
5.
Zhou, Q.; Mikkelsen, P.S.; Halsnæs, K.; A nbje g-Nielsen, K. F amewo k o economic plu ial lood isk
assessmen conside ing clima e change e ec s and adap a ion bene i s. J. Hyd ol.
2012
,414–415, 539–549.
[C ossRe ]
6.
Al es, A.; Ge sonius, B.; Kapelan, Z.; Vojino ic, Z.; Sanchez, A. Assessing he Co-Bene i s o g een-blue-g ey
in as uc u e o sus ainable u ban lood isk managemen . J. En i on. Manag.
2019
,239, 244–254. [C ossRe ]
[PubMed]
7.
Löwe, R.; U ich, C.; S o. Domingo, N.; Ma k, O.; Dele ic, A.; A nbje g-Nielsen, K. Assessmen o u ban
plu ial lood isk and e iciency o adap a ion op ions h ough simula ions—A new gene a ion o u ban
planning ools. J. Hyd ol. 2017,550, 355–367.
8.
Zhou, Q.; Pandu o, T.E.; Tho sen, B.J.; A nbje g-Nielsen, K. Adap ion o ex eme ain all wi h open u ban
d ainage sys em: An in eg a ed hyd ological cos -bene i analysis. En i on. Manag.
2013
,51, 586–601. [C ossRe ]
9.
Coope , W.; Ga cia, F.; Pape, D.; Ryde , D.; Wi he ell, B. Clima e Change Adap a ion Case S udy: Bene i -Cos
Analysis o Coas al Flooding Haza d Mi iga ion. J. Ocean Coas . Econ. 2016,3. [C ossRe ]
10.
Venka a amanan, V.; Lopez, D.; McCuskey, D.J.; Kie us, D.; McDonald, R.I.; Mille , W.M.; Packman, A.I.;
Young, S.L. Knowledge, a i udes, in en ions, and beha io ela ed o g een in as uc u e o lood
managemen : A sys ema ic li e a u e e iew. Sci. To al En i on. 2020,720, 137606. [C ossRe ]
11.
Wilke son, M.L.; Mi chell, M.G.E.; Shanahan, D.; Wilson, K.A.; I es, C.D.; Lo elock, C.E.; Rhodes, J.R.
The ole o socio-economic ac o s in planning and managing u ban ecosys em se ices. Ecosys . Se .
2018,31, 102–110. [C ossRe ]
12.
A nbje g-Nielsen, K. Quan i ica ion o clima e change e ec s on ex eme p ecipi a ion used o high esolu ion
hyd ologic design. U ban Wa e J. 2012,9, 57–65. [C ossRe ]
13.
Rod , R.; Na a o, X.; Casas, M.C.; Ribalaygua, J.; Russo, B.; Pouge , L.; Reda, A. In luence o clima e change
on IDF cu es o he me opoli an a ea o Ba celona (Spain). In . J. Clima ol. 2014,654, 643–654.
14.
Löwe, R.; U ich, C.; Kulahci, M.; Radhak ishnan, M.; Dele ic, A.; A nbje g-Nielsen, K. Simula ing lood isk
unde non-s a iona y clima e and u ban de elopmen condi ions—Expe imen al se up o mul iple haza ds
and a a ie y o scena ios. En . Model. So w. 2018,102, 155–171. [C ossRe ]
15. À
ea de Medi Ambien . Pla T
è
cnic pe L’ap o i amen dels Recu sos H
í
d ics Al e na ius a Ba celona: Vol
I/III Doc. N
ú
m. 1: Mem
ò
ia i Annexos; Reposi o i Obe de Coneixemen de l’Ajun amen de Ba celona:
Ba celona, Spain, 2009.
16.
BCN. Ecologia. Cobe es i Mu s Ve ds a Ba celona: Es udi sob e les exis en s, el po encial i les es e
è
gies
d’implan aci
ó
. 2010. A ailable online: h p://bcnecologia.ne /si es/de aul / iles/p oyec os/doc_cobe es_i_
mu s_ e ds_01m2010_0.pd (accessed on 1 Ap il 2020).
17.
Loca elli, L.; Gab iel, S.; Ma k, O.; Mikkelsen, P.S.; A nbje g-Nielsen, K.; Taylo , H.; Bockho n, B.; La sen, H.;
Kjølby, M.J.; Bliche , A.S.; e al. Modelling he impac o e en ion-de en ion uni s on sewe su cha ge and
peak and annual uno educ ion. Wa e Sci. Technol. 2015,71, 898–903. [C ossRe ] [PubMed]
18.
Monjo, R.; Gai
á
n, E.; P
ó
oles, J.; Ribalaygua, J.; To es, L. Changes in ex eme p ecipi a ion o e Spain using
s a is ical downscaling o CMIP5 p ojec ions. In . J. Clim. 2016,36, 757–769. [C ossRe ]
19.
Rus , H.W.; Richling, A.; Me edi h, E.; Fische , M.; Vagenas, C.; Kadow, C.; Ulb ich, U. Clima e P edic ions
and Downscaling o Ex eme Wea he . 2018. A ailable online: h p://www.p ojec bingo.eu/ou pu /clima e-
p edic ions (accessed on 1 Ap il 2020).
20.
Rod iguez-I u be, I.; Cox, D.R.; Isham, V. Some models o ain all based on s ochas ic poin p ocesses.
P oc. R. Soc. Lond. A Ma h. Phys. Sci. 1987,410, 269–288.
21.
Na ayanan, A.; Pi , R. Cos s o U ban S o mwa e Con ol P ac ices; Depa men o Ci il, Cons uc ion, and
En i onmen al Enginee ing, The Uni e si y o Alabama: Tuscaloosa, AL, USA, 2006.
22.
Bianchini, F.; Hewage, K. P obabilis ic social cos -bene i analysis o g een oo s: A li ecycle app oach.
Build. En i on. 2012,58, 152–162. [C ossRe ]
23.
Zhou, Q.; A nbje g-Nielsen, K. Unce ain y assessmen o clima e change adap a ion op ions using an
economic plu ial lood isk amewo k. Wa e 2018,10, 1877. [C ossRe ]
24.
Feng, H.; Hewage, K.N. Economic Bene i s and Cos s o G een Roo s. In Na u e Based S a egies o U ban and
Building Sus ainabili y; Else ie Inc.: Ams e dam, The Ne he lands, 2018; pp. 307–318. ISBN 9780128123249.
Sus ainabili y 2020,12, 3792 18 o 18
25.
Sa o i, D.; Ca alano, G.; Genco, M.; Panco i, C.; Si o i, E.; Vigne i, S.; Del Bo, C. Guide o Cos -bene i
Analysis o In es men P ojec s: Economic app aisal ool o Cohesion Policy 2014–2020. Eu . Commision
2014, 349. [C ossRe ]
26.
Smi h, K.; Wa d, R. Floods: Physical P ocesses and Human Impac s; Wiley: Hoboken, NJ, USA, 1998;
ISBN 978-0-471-95248-0.
27.
Ma
í
nez-Goma iz, E.; Loca elli, L.; Gue e o, M.; Russo, B.; Ma
í
nez, M. Socio-Economic Po en ial Impac s
Due o U ban Plu ial Floods in Badalona (Spain) in a Con ex o Clima e Change. Wa e
2019
,11, 2658.
[C ossRe ]
28.
Ma
í
nez-Goma iz, E.; G
ó
mez, M.; Russo, B.; S
á
nchez, P.; Mon es, J.A. Me hodology o he damage
assessmen o ehicles exposed o looding in u ban a eas. J. Flood Risk Manag. 2018, 1–15. [C ossRe ]
29.
Hallega e, S. An adap i e egional inpu -ou pu model and i s applica ion o he assessmen o he economic
cos o Ka ina. Risk Anal. 2008,28, 779–799. [C ossRe ] [PubMed]
30.
Lo enzo, C.; S anda di, G.; Bosello, F.; Mysiak, J. Assessing Di ec and Indi ec Economic Impac s o a Flood E en
h ough he In eg a ion o Spa ial and Compu able Gene al Equilib ium Modelling; Resea ch Pape s Issue RP0202
Decembe 2013; Cen o Eu o-Medi e aneo sui Cambiamen i Clima ici: Lecce, I aly, 2013.
31.
Loca elli, L.; Russo, B.; Ma inez, M. E alua ing heal h haza d o ba hing wa e s a ec ed by combined sewe
o e lows. Na . Haza ds Ea h Sys . Sci. Discuss. 2019, 1–19. [C ossRe ]
32.
Ba celona, D. Pla es a
è
gic dels espais li o als de la ciu a . A ailable online: h ps://www.decidim.ba celona/
p ocesses/PlaLi o alBCN (accessed on 1 Ap il 2020).
33. Tu ión-P a s, J.; Du o, J.A. Tou is seasonali y in Ca alonia. Tou . Econ. 2017,23, 846–853. [C ossRe ]
34.
De B uin, K.; Dellink, R.; Ag awala, S.; Dellink, R. Economic Aspec s o Adap a ion o Clima e Change:
In eg a ed Assessmen Modelling o Adap a ion Cos s and Bene i s. Oecd En i on. Wo k. Pap.
2009
,22, 36–38.
35.
Dec e o 459/2013. de 10 de Diciemb e, Sob e los Ve idos E ec uados Desde Tie a al Ma . Bole
í
n O icial del Pa
í
s
Vasco; Depa amen o de Medio Ambien e y Poli ica Te i o ial: Bilbao, Spain, 2014.
36.
Hol , A. Ex Pos E alua ion o Cohesion Policy In e en ions 2000-2006 Financed by he Cohesion Fund. WP C Cos
Bene i Analysis o En i onmen P ojec s; Publica ions O ice o Eu epean Union: Luxembou g, 2011.
37.
Chiabai, A.; Gala aga, I. De e mining Discoun Ra es: An Applica ion o he Equi alency P inciple; EU:
B ussels, Belgium, 2016.
38.
G i in, R.C. Wa e Resou ce Economics: The Analysis o Sca ci y, Policies, and P ojec s; MIT P ess:
Camb idge, MA, USA, 2006; ISBN 9780262072670.
39. Aaheim, A. The de e mina ion o op imal clima e policy. Ecol. Econ. 2010,69, 562–568. [C ossRe ]
40.
S e n, N. The Economics o Clima e Change: The S e n Re iew; Camb idge Uni e si y P ess: Camb idge, UK,
2007; ISBN 9780511817434.
41.
Pea ce, D.; A kinson, G.; Mou a o, S. Cos -Bene i Analysis and he En i onmen : Recen De elopmen s;
O ganisa ion o Economic Coope a ion and De elopmen (OECD): Pa is, F ance, 2006; ISBN 9789264010055.
42.
Oxe a a Social Time P e e ence o Use in Long-Te m Discoun ing. A ailable online: h ps://www.oxe a.com/
publica ions/a-social- ime-p e e ence- o -use-in-long- e m-discoun ing/(accessed on 3 Ma ch 2020).
43.
Loca elli, L.; Ma k, O.; Mikkelsen, P.S.; A nbje g-Nielsen, K.; Wong, T.; Binning, P.J. De e mining he ex en o
g oundwa e in e e ence on he pe o mance o in il a ion enches. J. Hyd ol.
2015
,529, 1360–1372. [C ossRe ]
44.
Loca elli, L.; Ma k, O.; Mikkelsen, P.S.; A nbje g-Nielsen, K.; Be gen Jensen, M.; Binning, P.J. Modelling
o g een oo hyd ological pe o mance o u ban d ainage applica ions. J. Hyd ol.
2014
,519, 3237–3248.
[C ossRe ]
45.
Bockho n, B.; Klin , K.E.S.; Loca elli, L.; Pa k, Y.-J.; Binning, P.J.; Sudicky, E.; Be gen Jensen, M. Fac o s
a ec ing he hyd aulic pe o mance o in il a ion based SUDS in clay. U ban Wa e J.
2017
,14, 125–133.
[C ossRe ]
46.
Raso, J.; Malg a , P.; Cas illo, F. Imp o emen in he selec ion o design s o ms o he New Mas e D ainage
Plan o Ba celona. Wa e Sci. Technol. 1995,32, 217–224. [C ossRe ]
47.
Olsen, A.S.; Zhou, Q.; Linde, J.J.; A nbje g-Nielsen, K. Compa ing me hods o calcula ing expec ed annual
damage in u ban plu ial lood isk assessmen s. Wa e 2015,7, 255–270. [C ossRe ]
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