Stream restoration in the Netherlands – two examples ... · Stream restoration in the Netherlands...
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Transcript of Stream restoration in the Netherlands – two examples ... · Stream restoration in the Netherlands...
Stream restoration in the Netherlands Stream restoration in the Netherlands ––
two examples differing in scaletwo examples differing in scale
Roos LoebKarin DidderenPiet Verdonschot
Contents
� National survey on stream restoration
� Small-scale restoration: woody debris in the Jufferbeek
� Large-scale-project: restoration of the Geeserstroom
� Conclusions
Stream restoration survey – where?
0
10
20
30
40
50
upper course
middle course
lower course
upper&middle course
upper to lower c
ourse
middle&lower course
restoration projects per stream course
% o
f p
roje
cts
Stream restoration survey – measures
0
20
40
60
80
remeander(active)
reprofile raise drainagebase
raisegroundwater level
developinundation zone
increase waterretetion/storage
hydrology & morphology
01020304050607080
low gradientbanks
fish migrationpaths
asymetricalprofile
plant wood onbanks
stream and bank arrangement
01020304050607080
change landuse
top soilremoval
buffer zones reduce inflowcontaminants
water quality
% o
f p
roje
cts
% o
f p
roje
cts
% o
f p
roje
cts
Stream restoration inquiry – monitoring
0
10
20
30
40
50
hydrology
morphology
water quality fish
macrophytes
bank vegetation
macro!invertebrates
phytobenthos
unknownnothing
monitoring both before and after
restoration
Wood experiment in the Jufferbeek
� Free-flowing discharge� Removal of leaves and branches� 1-5% coverage of organic matter (naturally 25% wood, 25%
leaves)
� Effects� Habitat disappearance for stream-dwelling organisms� Homogeneity of habitats� Increased discharge� Bed-incisions and drought
� Wood addition could be a cheap restoration measure for a small part of a stream course
� Jufferbeek: upper course in the east of the Netherlands� 2 locations: upstream (control) and section with wood
addition (300 m)� Spring 2006: wood was added to a coverage 25%
wood section
control section
Wood experiment in the Jufferbeek
0%
10%20%
30%40%
50%
60%70%
80%90%
100%
Apr-05
Oct-05
Oct-06
Feb-07
Apr-07
Jul-07
Sep-07
Nov-07
Apr-05
Oct-05
Oct-06
Feb-07
Apr-07
Jul-07
Sep-07
Nov-07
c o n t r o l w o o d s e c t
cove
rag
e
fdetri cdetri silt leaves veg wood bran sand
Wood experiment in the Jufferbeek
finedetritus
coarsedetritus
silttwigsleavesvegetationsandfine gravel
flo
wve
loci
ty(m
/s)
0,40
0,30
0,20
0,10
0,00 a b c dc c d e
Wood experiment
�2
�1.5�1
�0.50
0.51
1.52
2.53
E uk ie ffe rie lla c la r ip enn isN eo lim nom y ia spM id eop s is c ra ss ip esT ub ifex tu b ifexL accob iu s b ip un c ta tu sL im nod rilu s h o ffm e is te riC h ry sop ilu s spL eb ertia in aequ a lisT ub ific id aeN ep a c in e reaA u lod rilu s japon icu sP rod iam esa o livaceaV e lia c ap ra iP o tam o th rix b edo tiL eb ertia lin ea taN eum an ia v e rn a lisH yd ro chu s spP o lyp ed ilum sca la en umO ph id ona is se rp en tin aE lod es spL im nod rilu s p ro fund ico laA eshn a spM ic rop te rn a la te ra lisC e ra top ogon id aeS tagn ico la spB a th yom pha lu s con to rtu sH ippeu tis com p lan a tu sH yg ro tu s in aequ a lisH e loph o ru s a eq u a lisM o loph ilu s spN eph ro tom a spZ avre lie lla spC o ryn on eu ra c f an ten n a lisT aban id aeP lec tro cn em ia con sp e rsaG yrau lu s spB e raeod es m inu tu sS tem pe llin a spSpe rchon th ien em ann iG am m aru s p u lexB ae tis v e rn u sS egm en tin a n it id aA rrenu ru s c y lin d ra tu sC lado tan y ta rsu s spR ad ix o va taZ avre lim y ia spA n acaen a spS ia lis lu ta riaC lo eon d ip te rumP isid ium spG a lb a trun ca tu laP ro c lad iu s spP roa se llu s m e rid ian u s
taxon gewicht
30
35
40
45
50
55
60
before after
nu
mb
ero
f m
acro
inve
rteb
rate
tax
a control
wood section
Taxon increase
Large-scale restoration: Geeserstroom
Before� Deeply incised, canalized, short length, limited slope� Eutrophication from agriculture and sewer overflow� No fish migration possible (weirs)
Large-scale restoration: Geeserstroom
Restoration measures� New, meandering stream bed (2005)� Close-off + diversion agricultural waters� Only 1 weir with fish ladder
Historical situation
Large-scale restoration: Geeserstroom
Historical situation
Large-scale restoration: Geeserstroom
110115max water depth (cm)
2770average water depth (cm)
8512max width (m)
97average width (m)
2110slope (%)
8.96.0distance to fish ladder (km)
after restorationbeforerestoration
Large-scale restoration: Geeserstroom
Roonboomdijk
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
Jan-
05
Apr-0
5
Jul-0
5
Oct-05
Jan-
06
Apr-0
6
Jul-0
6
Oct-06
Jan-
07
Apr-0
7
Jul-0
7
Oct-07
conc
entr
atio
nph
osph
orus
(mg
P/l)
DIP
DOP
Large-scale restoration: Geeserstroom
Roonboomdijk
0
1
2
3
4
5
6
7
8
jan-0
5
apr-0
5
jul-0
5
okt-0
5
jan-0
6
apr-0
6
jul-0
6
okt-0
6
jan-0
7
apr-0
7
jul-0
7
okt-0
7
conc
entr
atio
nni
trog
enN
mg/
l
DIN
DON
Large-scale restoration: Geeserstroom
1
0
µ
m
� 3 common, (hyper) eutrophic taxa dominant (pioneer species)
2µ
m
5µ
m
Cocconeis placentula Achnanthidium minutissimum Gomphonema parvulum
Large-scale restoration: Geeserstroom
Diatoms
macroinvertebrates(dis)appearance
0.1
1
10
Hyd
raca
rina
Biv
alvi
a
Hiru
dine
a
Am
phip
oda
Meg
alop
tera
Odo
nata
Olig
ocha
eta
Tric
hopt
era
Gas
trop
oda
Col
eopt
era
Bra
chyc
era
Eph
emer
opte
ra
Isop
oda
Lepi
dopt
era
Pla
tyhe
lmin
thes
Nem
atoc
era
Chi
rono
mid
ae
Het
erop
tera
Rat
io a
ppea
red/
disa
ppea
red
taxa
Large-scale restoration: Geeserstroom
Index for rheophilic species Index for drought tolerant species
n.s.
Large-scale restoration: Geeserstroommacroinvertebrates
*
Conclusions
� Dispersion plays an important role in (re)colonisation; flying species reach restored stream more easily than non-flying species
� (Re)colonisation and vegetation development take time: long-term monitoring necessary
� Exceeding nutrient norms may hamper development of ecology
Conclusions
� Many projects in the Netherlands only focus on a small section of a stream, no restoration of entire catchments (+ problems from upstream sections)
� Most effort put into hydrological and morphological changes, little into nutrients
� Many projects are not monitored (especially not for biological targets). A before-after-control-impact monitoring would be best.
� Need for scientific research to gain do’s and don’ts in lowland stream restoration