Wi h Ch is ophe wi mann
Clima e change is in ensi ying wea he ex emes,
wi h mo e hea y ain all and d ough s, e en in
adi ionally we egions like he Ne he lands.
Known o i s enginee ed wa e managemen , he
coun y is now u ning o na u e-based solu ions,
including sponge measu es.
These aim o es o e landscapes’ abili y o abso b,
s o e, and elease wa e g adually, helping o
mi iga e bo h d ough s and loods. Howe e , could
measu es o one ex eme wo sen he o he ?
Ch is ophe , a PhD s uden in hyd ology, explo es
his ques ion h ough hyd ological modeling.
C edi s :
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© 2025 - In e na ional O ice o Wa e o he SpongeScapes p ojec . Sc ip , d awing and colou ing o he comics:
Élisa Bézie and Jean Combe e (OiEau)
Ch is ophe Wi mann's
PhD hesis, supe ised by:
P o . J. Wallinga (Wageningen Uni e si y), P o . A.
Wee s (Wageningen Uni e si y/Del a es), D . A La ssen
(Wageningen Uni e si y), D . E. Penning (Del a es)
P oo eading :
Ch is ophe Wi mann
D . Ellis Penning (Del a es)
Tex be o e sc ip :
Chloé Déchele e
(OiEau)
Floods and D ough s:
Welcome o he Chaamse beken
ca chmen ! A egion in he
sou h o he Ne he lands ha
has his o ically been e y we ...
He e, la land means ha wa e uns
o slowly and s ays longe , while
sandy soils soak up wa e like a sponge.
Du ing hea y ains,
he soil quickly becomes sa u a ed.
Tha ’s why a me s buil d ains and
di ches - o keep ee
and c ops d y. D ains made we land
a mable… bu wi h longe
d ough s, we now ealize hey
ac ually make hings wo se:
soils d y ou as e .
In ac , in he egion,
clima e change is al eady isible wi h
hea ie ains and longe d ough s. One solu ion is o emo e some d ains
so wa e s ays in he g ound longe -
u ning ields back in o sponges.
Bu he e's he ques ion: could i be
ha in some cases measu es aimed a
mi iga ing one ex eme (d ough s)
wo sen he o he ( loods)?
To ind ou , I use hyd ological modelling. Models
help us unde s and complex sys ems. They a e
scien i ic ools ha b ing nuance and ealism.
In my esea ch, I buil a hyb id model
ha combines lood and d ough dynamics.
No mally, hey’ e s udied sepa a ely because
hey ollow di e en na u al
p ocesses and ules.
Wa e is always on he mo e - in he su ace in
i e s and lakes, and unde g ound in aqui e s.
Models help unde s and
be e how wa e ci cula es on he
su ace o unde g ound.
Fo example, in summe , many i e s a en’ ed by ain
a all… bu by g oundwa e ising in o he i e .
G oundwa e mo es slowly, so we
measu e i s low in olume pe day.
Su ace wa e mo es
much as e , so we measu e
hei low in olume pe second.
And loods can de elop e y quickly,
so high p ecision is needed.
The icky pa o building a hyb id
model? Su ace wa e and g oundwa e
un on o ally di e en clocks!
They also help
unde s and he in e ac ions:
how wa e can mo e up om
g oundwa e o i e s, o down
in o soils, depending on seasons,
soil ypes, and o he ac o s.
Despi e hese challenges, we
de eloped a hyb id model o
simula e wha would happen in imes
o hea y loods i d ains a e emo ed.
1, Wi hou d ains, soils
a e al eady sa u a ed, so
hey can’ abso b loodwa e
- leading o mo e uno
and highe i e low.
2, The low peak inc eased by 10%.
The low peak is he g ea es amoun
o wa e mo ing h ough he s eam
du ing a lood e en . An inc ease by 10%
means he lood is mo e se e e
3, Less g oundwa e lowed
in o i e s. Wi hou d ains, g oundwa e
illed up as e and spilled as
su ace uno ins ead.
In he end, he looded a ea
nea ly doubled!
O cou se, models a e simpli ica ions.
The in e ac ion be ween su ace wa e
and g oundwa e is simpli ied. In eal
li e, wa e akes many hidden pa hs.
Whe e a e hey ..
Le ’s swim o e he e.
THE SIMULATION REVEALED
THREE KEY FINDINGS ...
S ill, his shows an
impo an challenge: any
measu e aken o educe
d ough impac s can
also a ec loods,
and ice e sa.
And wha i loods and d ough s keep ge ing wo se?
A e we eady o change land use en i ely?
Fo example, do we accep ha ce ain a eas a e
looded mo e equen ly?
And how do we make hose land use changes ai ?
Floods damage c ops and homes... bu na u e
(especially we lands) bene i s om ex a wa e .
How do we balance ood, people, and na u e?
So a , my esea ch ocused mainly on wa e
quan i y, bu he e’s mo e o explo e wi h
modelling, o example he links wi h biodi e si y,
wa e quali y, ood p oduc ion, e c.
My esea ch is abou explo ing
hese ade-o s wi h models, and help
inding sponge s a egies ha can
ackle d ough s and loods oge he .
Floods
Flood
d ough
D ough s
