natural england green bridges guide · 2019. 1. 16. · structures include wildlife overpasses and...

29
i Green Bridges Technical Guidance Note 09/2015 December 2015 ________________________________________________________________________________________ Contents Foreword by Chairman of LI Technical Committee i Introduction 1 When to consider a green bridge 3 Planning for a green bridge structure 6 Choosing a green bridge structure 11 Case Studies 16 Post-construction recommendations 16 References 17 This Guidance Note guide provides information and guidance on planning for a green bridge, the different types of green bridge that can be used and example case studies. It also highlights some of the wider multi-functional benefits that green bridges can provide.

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Page 1: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

i

Gre

en B

ridge

s

Tech

nica

l Gui

danc

e N

ote

09/2

015

Dece

mbe

r 201

5

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

____

Cont

ents

Fore

wor

d by

Cha

irman

of L

I Tec

hnic

al C

omm

ittee

i

Intr

oduc

tion

1

Whe

n to

con

sider

a g

reen

brid

ge

3

Plan

ning

for a

gre

en b

ridge

stru

ctur

e 6

Choo

sing

a gr

een

brid

ge st

ruct

ure

11

Case

Stu

dies

16

Post

-con

stru

ctio

n re

com

men

datio

ns

16

Refe

renc

es

17

This

Guid

ance

Not

e gu

ide

prov

ides

info

rmat

ion

and

guid

ance

on

plan

ning

for a

gre

en b

ridge

, the

diff

eren

t typ

es o

f gre

en b

ridge

that

can

be

used

and

exa

mpl

e ca

se

stud

ies.

It a

lso h

ighl

ight

s som

e of

the

wid

er m

ulti-

func

tiona

l ben

efits

that

gre

en b

ridge

s can

pro

vide

.

Page 2: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

i

Fore

wor

d

Frag

men

tatio

n of

the

land

scap

e, lo

ss o

f its

pat

tern

s an

d fe

atur

es a

nd d

isrup

tion

to e

cosy

stem

con

nect

ivity

are

maj

or p

robl

ems.

Gre

en b

ridge

s ca

n pl

ay a

par

t in

en

surin

g co

nnec

tivity

is r

etai

ned

or r

eins

tate

d. A

s ju

st o

ne r

ecen

t ex

ampl

e, E

uan

Mah

arg’

s aw

ard-

win

ning

con

cept

for

tw

o gr

een

brid

ges

in t

he S

even

Loc

hs

Wet

land

Par

k in

Sco

tland

has

bee

n an

insp

iratio

n.

The

repo

rt o

n w

hich

thi

s gu

idan

ce n

ote

is en

tirel

y ba

sed,

with

out

subs

tant

ive

alte

ratio

n, w

as w

ritte

n by

Lan

d U

se C

onsu

ltant

s fo

r an

d fo

llow

ing

rese

arch

co

mm

issio

ned

by N

atur

al E

ngla

nd.

Und

erst

anda

bly

refe

renc

es a

re to

the

regu

lato

ry e

nviro

nmen

t in

Engl

and

but t

he s

tudy

is b

ased

on

rese

arch

inte

rnat

iona

lly a

nd

in p

artic

ular

prin

cipl

es a

nd p

ract

ice

deve

lope

d in

the

Net

herla

nds.

It i

s of

cou

rse

poss

ible

that

diff

eren

t reg

ulat

ions

, lan

dsca

pe p

atte

rns

and

feat

ures

and

clim

atic

co

nditi

ons

in o

ther

cou

ntrie

s m

ay r

equi

re a

djus

tmen

ts t

o pr

actic

e bu

t th

e La

ndsc

ape

Inst

itute

bel

ieve

s th

at t

he p

rinci

ples

are

wel

l-est

ablis

hed

and

wid

ely

appl

icab

le.

The

Inst

itute

ther

efor

e co

mm

ends

this

guid

ance

to p

ract

ition

ers o

n th

is ba

sis.

Plea

se n

ote

that

Nat

ural

Eng

land

ow

ns t

he In

telle

ctua

l Pro

pert

y Ri

ghts

to

the

repo

rt b

ut h

as li

cens

ed t

he L

ands

cape

Inst

itute

to

publ

ish

it in

the

for

m o

f a

Land

scap

e In

stitu

te g

uida

nce

note

und

er th

e O

pen

Gov

ernm

ent L

icen

ce.

Mar

k Tu

rnbu

ll FL

I, Ch

airm

an o

f LI T

echn

ical

Com

mitt

ee, D

ecem

ber 2

015

Page 3: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

1

Intr

oduc

tion

It is

wel

l do

cum

ente

d th

at t

rans

port

inf

rast

ruct

ure

can

have

a n

egat

ive

impa

ct o

n th

e en

viro

nmen

t. R

oad

and

rail

sche

mes

can

frag

men

t hab

itats

an

d cr

eate

a b

arrie

r to

spe

cies

mov

emen

t ca

usin

g di

rect

impa

cts

thro

ugh

spec

ies

colli

sions

with

veh

icle

s.

Road

s an

d ra

ilway

s ca

n ca

use

habi

tat

frag

men

tatio

n be

caus

e th

ey b

reak

larg

e ha

bita

t ar

eas

into

sm

all,

isola

ted

habi

t pa

tche

s w

hich

sup

port

few

er i

ndiv

idua

ls.

How

ever

, re

sear

ch h

as

show

n th

at w

hen

man

aged

app

ropr

iate

ly e

xist

ing

tran

spor

t cor

ridor

s ha

ve

the

pote

ntia

l to

be

enha

nced

to

prov

ide

conn

ectin

g co

rrid

ors

thro

ugh

othe

rwise

bio

dive

rse

poor

land

scap

es s

uch

as u

rban

are

as a

nd in

tens

ivel

y fa

rmed

land

scap

es.

In l

ands

cape

and

visu

al t

erm

s lin

ear

tran

spor

t co

rrid

ors

can

seve

r an

d fr

agm

ent

cohe

sive

area

s of

val

ued

land

scap

e; h

avin

g a

detr

imen

tal e

ffect

on

the

spec

ial q

ualit

ies

that

und

erpi

n th

e na

tura

l bea

uty

of o

ur d

esig

nate

d la

ndsc

apes

(e.

g. N

atio

nal P

ark

and

Area

s of

Out

stan

ding

Nat

ural

Bea

uty)

an

d ad

vers

ely

affe

ctin

g th

e ch

arac

ter

of o

ur v

alue

d la

ndsc

apes

, bo

th

natio

nally

des

igna

ted

land

scap

es a

nd o

ther

s.

Such

sch

emes

can

res

ult

in

exte

nsiv

e sc

arrin

g fr

om c

ut a

nd f

ill o

r em

bank

men

ts, a

nd n

otch

es o

n th

e sk

ylin

e, c

onfli

ctin

g w

ith t

he l

ocal

lan

dfor

m;

seve

ring

and

disr

uptin

g th

e lo

cal p

atte

rn a

nd d

etai

l of t

he la

ndsc

ape

such

as

impo

rtan

t fie

ld b

ound

ary

patt

erns

, and

impo

sing

asso

ciat

ed u

rban

infr

astr

uctu

re, i

nclu

ding

ligh

ting,

in

oth

erw

ise ru

ral,

tran

quil

plac

es.

The

time

dept

h an

d hi

stor

ic c

hara

cter

of

the

land

scap

e ca

n be

cha

nged

and

hist

oric

pat

tern

s, li

near

fea

ture

s an

d ro

utes

may

be

seve

red.

The

sig

nific

ance

and

set

ting

of h

istor

ic a

sset

s m

ay

also

be

chan

ged.

Road

and

rai

l in

fras

truc

ture

also

im

pact

s on

the

loc

al c

onne

ctiv

ity a

nd

acce

ssib

ility

of t

he la

ndsc

ape

seve

ring

links

bet

wee

n pl

aces

. In

fras

truc

ture

ca

n ac

t as a

bar

rier t

o ac

cess

to g

reen

spac

e an

d m

ay se

ver e

xist

ing

wal

king

, cy

clin

g an

d ho

rse

ridin

g ro

utes

. H

owev

er so

me

road

or r

ail i

nfra

stru

ctur

e if

sens

itive

ly

desig

ned

may

pr

esen

t op

port

uniti

es

for

icon

ic

land

scap

e fe

atur

es su

ch a

s gre

en b

ridge

s.

Wild

life

cros

sing

stru

ctur

es h

ave

been

use

d in

Eur

ope

and

Nor

th A

mer

ica

to

faci

litat

e m

ovem

ent

thro

ugh

land

scap

es

frag

men

ted

by

road

s. T

hese

stru

ctur

es in

clud

e w

ildlif

e ov

erpa

sses

and

gre

en b

ridge

s, b

ridge

s, c

ulve

rts,

and

pipe

s.

Gree

n br

idge

s ar

e re

lativ

ely

new

with

in t

he U

K, w

ith o

nly

a sm

all n

umbe

r in

exi

sten

ce.

This

guid

e is

desig

ned

to p

rovi

de in

form

atio

n on

whe

n it

may

be

appr

opria

te to

con

sider

inst

allin

g a

gree

n br

idge

as

part

of

a p

roje

ct.

As

wel

l as

new

inf

rast

ruct

ure

sche

mes

, re

trof

ittin

g gr

een

brid

ges

on

exist

ing

sche

mes

m

ay

be

an

optio

n to

al

levi

ate

know

n bl

acks

pots

for

wild

life

colli

sions

or

whe

re t

here

is a

wid

er g

oal t

o jo

in u

p la

ndsc

apes

an

d ec

osys

tem

s.

Su

ch

retr

ofitt

ing

may

en

hanc

e w

ildlif

e co

nnec

tivity

an

d in

crea

se

the

perm

eabi

lity

of

the

land

scap

e,

whi

le

pote

ntia

lly e

nhan

cing

the

attr

activ

enes

s an

d vi

sual

cha

ract

er o

f an

exist

ing

cros

sing.

Thr

ough

cre

atin

g hi

gh q

ualit

y, v

isual

ly a

ttra

ctiv

e an

d co

nven

ient

cr

ossin

gs f

or p

edes

tria

ns,

cycl

ists

and

hors

e rid

ers,

gre

en b

ridge

s ca

n en

cour

age

mor

e pe

ople

to u

se th

ese

rout

es w

ith re

sulti

ng h

ealth

, wel

lbei

ng

and

othe

r ben

efits

.

This

guid

e pr

ovid

es i

nfor

mat

ion

on p

lann

ing

for

a gr

een

brid

ge,

the

diffe

rent

type

s of

gre

en b

ridge

that

can

be

used

and

exa

mpl

e ca

se s

tudi

es.

The

guid

e al

so h

ighl

ight

s so

me

of t

he w

ider

mul

ti-fu

nctio

nal b

enef

its t

hat

gree

n br

idge

s can

pro

vide

for p

eopl

e an

d co

mm

uniti

es.

This

gui

de is

bas

ed u

pon

a lit

erat

ure

revi

ew o

n gr

een

brid

ges

unde

rtak

en

for N

atur

al E

ngla

nd b

y La

nd U

se C

onsu

ltant

s:

Nat

ural

Eng

land

(201

5) G

reen

Brid

ges

– Li

tera

ture

Rev

iew

. Nat

ural

Eng

land

Co

mm

issio

ned

Repo

rt

In s

umm

ary,

the

lite

ratu

re r

evie

w f

ound

tha

t gr

een

brid

ges

do p

rovi

de

miti

gatio

n fo

r ec

olog

ical

sev

eran

ce, w

ith e

vide

nce

of w

ildlif

e us

e re

cord

ed

on a

lar

ge n

umbe

r of

brid

ges.

Gr

een

brid

ges

wer

e fo

und

to p

rovi

de

habi

tats

in t

heir

own

right

, w

ith e

stab

lishe

d br

idge

s co

mpl

emen

ting

and

conn

ectin

g th

e su

rrou

ndin

g ha

bita

t.

Som

e ev

iden

ce w

as a

lso f

ound

to

show

tha

t gr

een

brid

ges

can

be u

sed

to a

ddre

ss l

ands

cape

and

acc

ess

seve

ranc

e.

Beyo

nd t

hese

asp

ects

som

e ev

iden

ce w

as a

lso f

ound

to

dem

onst

rate

a r

ole

in p

rovi

ding

wid

er e

cosy

stem

ser

vice

s, fo

r ex

ampl

e by

re

cycl

ing

rain

wat

er t

o irr

igat

e th

e br

idge

str

uctu

re.

In

the

liter

atur

e

For

the

purp

oses

of th

is g

uide

a g

reen

bridg

e is

def

ined

as

an:

Art

ifici

al s

truc

ture

ove

r ro

ad o

r ra

il in

fras

truc

ture

whi

ch is

eith

er

vege

tate

d or

pro

vide

s so

me

wild

life

func

tion

Page 4: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

2

revi

ewed

gre

en b

ridge

s ar

e al

so re

ferr

ed to

as

ecod

ucts

, lan

dsca

pe b

ridge

s, w

ildlif

e br

idge

s an

d w

ildlif

e cr

ossin

gs.

The

revi

ew d

id n

ot in

clud

e cu

t an

d co

ver

tunn

els1 .

It

is ac

know

ledg

ed t

hat

muc

h of

the

lite

ratu

re h

as

conc

entr

ated

on

the

role

of g

reen

brid

ges

as w

ildlif

e cr

ossin

gs, a

nd to

dat

e th

ere

is re

lativ

ely

little

info

rmat

ion

on t

he e

ffect

iven

ess

for

land

scap

e an

d vi

sual

miti

gatio

n.

Guid

e st

ruct

ure

This

guid

e is

desig

ned

to g

ive

a cl

ear p

athw

ay o

n pl

anni

ng a

nd d

esig

ning

a

gree

n br

idge

str

uctu

re.

It is

not

inte

nded

to

be a

det

aile

d de

sign

guid

e,

cove

ring

tech

nica

l eng

inee

ring

aspe

cts

as th

ese

will

larg

ely

be s

ite s

peci

fic.

The

guid

e ai

ms

to id

entif

y th

e br

oad

desig

n pr

inci

ples

for g

reen

brid

ges

so

that

the

y ar

e ab

le t

o pr

ovid

e ec

olog

ical

, lan

dsca

pe a

nd a

cces

s fu

nctio

ns,

depe

ndin

g on

the

aim

s.

In te

rms

of p

lann

ing,

the

guid

e la

ys o

ut th

e ke

y co

nsid

erat

ions

to ta

ke in

to

acco

unt

whe

n de

cidi

ng i

f a

gree

n br

idge

is a

n ap

prop

riate

app

roac

h fo

r pr

ojec

t sp

ecifi

c m

itiga

tion

or w

ider

bio

dive

rsity

/ la

ndsc

ape/

acce

ss g

oals.

O

nce

the

cons

truc

tion

of a

gre

en b

ridge

is id

entif

ied

as a

sui

tabl

e op

tion

then

det

ails

are

give

n on

the

wor

k re

quire

d to

pos

ition

the

brid

ge a

nd

deve

lop

the

desig

n.

Desig

n op

tions

are

the

n pr

ovid

ed a

long

with

cas

e st

udy

exam

ples

.

The

appr

oach

with

in t

his

guid

e ha

s la

rgel

y be

en d

evel

oped

fro

m t

he

info

rmat

ion

gath

ered

with

in t

he l

itera

ture

rev

iew

. H

owev

er,

whe

re t

he

liter

atur

e re

view

onl

y pr

ovid

ed li

mite

d or

no

info

rmat

ion

on a

n as

pect

then

LU

C’s v

iew

s are

pre

sent

ed.

This

is cl

early

refe

renc

ed in

the

text

.

Lim

itatio

ns o

f the

gui

de

The

inte

rnat

iona

l lite

ratu

re re

view

of g

reen

brid

ges

has

reve

aled

that

ther

e ar

e kn

owle

dge

gaps

, for

exa

mpl

e, in

term

s of

ass

essin

g if

gree

n br

idge

s ar

e su

cces

sful

in m

aint

aini

ng g

ene

flow

of p

opul

atio

ns w

here

pop

ulat

ions

hav

e be

en s

ever

ed b

y ro

ad a

nd ra

il in

fras

truc

ture

. Thi

s is

larg

ely

due

to a

lack

of

long

term

mon

itorin

g da

ta.

1 i.e.

con

stru

ctin

g a

tunn

el b

y ex

cava

ting

a cu

ttin

g to

the

req

uire

d de

pth

and

then

bac

kfill

ing

the

exca

vation

ove

r th

e tu

nnel

roo

f do

wn

to a

dep

th

The

maj

ority

of l

itera

ture

focu

ses

arou

nd b

ridge

s ov

er r

oads

; how

ever

it is

co

nsid

ered

tha

t th

e co

ncep

ts u

sed

for

thes

e br

idge

s ar

e ap

plic

able

ove

r ra

ilway

s.

Ther

e is

limite

d in

form

atio

n re

gard

ing

gree

n br

idge

s bu

ilt f

or p

urpo

ses

othe

r tha

n w

ildlif

e, fo

r exa

mpl

e, to

brin

g la

ndsc

ape

bene

fits.

In t

erm

s of

asc

erta

inin

g ty

pica

l co

sts

for

gree

n br

idge

s, t

here

are

som

e de

tails

reg

ardi

ng c

osts

of c

onst

ruct

ed b

ridge

s bu

t the

se a

re li

mite

d an

d as

su

ch o

nly

roug

h in

dica

tions

of

likel

y co

sts

of n

ew b

ridge

s ar

e pr

ovid

ed in

th

e gu

idan

ce b

elow

. I

t is

note

d th

ese

are

heav

ily c

avea

ted

as lo

cal s

ite

aspe

cts w

ill in

fluen

ce c

osts

, suc

h as

topo

grap

hy, g

eolo

gy a

nd h

ydro

logy

.

This

guid

e do

es n

ot c

onsid

er t

he v

isual

im

pact

s of

gre

en b

ridge

s on

la

ndsc

ape,

but

mor

e sp

ecifi

cally

rel

ates

to

the

way

the

y m

itiga

te f

or

land

scap

e se

vera

nce

from

road

and

railw

ay in

fras

truc

ture

.

This

guid

e so

lely

focu

ses

on g

reen

brid

ges

and

does

not

incl

ude

tunn

els

or

cut a

nd c

over

stru

ctur

es.

Aim

s of g

reen

brid

ge st

ruct

ures

Whe

n pl

anni

ng fo

r a g

reen

brid

ge, i

t is i

mpo

rtan

t tha

t pro

ject

aim

s are

cle

ar

from

the

outs

et.

Gree

n br

idge

s ca

n ei

ther

be

built

as

part

of n

ew p

roje

cts

or r

etro

fitte

d in

to

exist

ing

infr

astr

uctu

re w

here

a n

eed

is id

entif

ied.

The

ai

ms o

f a g

reen

brid

ge m

ay b

e to

:

- M

aint

ain,

res

tore

or

enha

nce

eco

logi

cal

conn

ectiv

ity (

to r

educ

e sp

ecie

s fra

gmen

tatio

n an

d m

itiga

te e

colo

gica

l sev

eran

ce)

- Pr

ovid

e ha

bita

t enh

ance

men

t and

redu

ce h

abita

t fra

gmen

tatio

n -

Redu

ce sp

ecie

s mor

talit

y fr

om c

ollis

ions

-

Mai

ntai

n, re

stor

e or

enh

ance

hist

oric

al li

nks

- M

aint

ain,

rest

ore

or e

nhan

ce a

cces

s and

recr

eatio

nal l

inks

-

Mai

ntai

n, r

esto

re o

r en

hanc

e a

conn

ecte

d la

ndsc

ape

reso

urce

or

feat

ure

- Re

duce

visu

al e

ffect

s and

frag

men

tatio

n -

Prov

ide

ecos

yste

m se

rvic

es

- Pr

ovid

e al

l or s

ome

of th

e ab

ove

Page 5: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

3

Whe

n to

con

side

r a g

reen

brid

ge

Whe

n co

ntem

plat

ing

a gr

een

brid

ge, c

are

shou

ld b

e ta

ken

to u

nder

stan

d th

e ad

vant

ages

an

d di

sadv

anta

ges

it m

ay

offe

r co

mpa

red

to

othe

r en

gine

erin

g so

lutio

ns (

p.5)

. Al

so,

a gr

een

brid

ge m

ay p

rovi

de a

loca

lised

be

nefit

for

land

scap

e, b

ut w

ill n

ot m

itiga

te t

he im

pact

s of

line

ar t

rans

port

in

fras

truc

ture

ove

r a w

ide

area

.

Gree

n br

idge

s may

be

inst

alle

d fo

r new

road

and

rail

sche

mes

, but

may

also

be

ret

ro-fi

tted

ove

r ex

istin

g in

fras

truc

ture

. W

hen

cons

ider

ing

if a

gree

n br

idge

is a

n ap

prop

riate

opt

ion

the

key

driv

ers

will

be

ecol

ogic

al, l

ands

cape

an

d ac

cess

con

sider

atio

ns.

The

req

uire

men

t fo

r a

gree

n br

idge

may

be

driv

en b

y on

e of

the

se, o

r by

mul

tiple

driv

ers.

Eve

n w

here

a p

roje

ct h

as

only

one

mai

n dr

iver

, th

e us

e of

a g

reen

brid

ge m

ay p

rovi

de m

ultip

le

bene

fits

beyo

nd t

hat

of t

he d

river

. T

he t

able

bel

ow i

dent

ifies

the

key

dr

iver

s and

like

ly tr

igge

rs in

rela

tion

to th

ese.

Eco

log

ical

La

nd

scap

e A

cces

s

Sev

eran

ce o

f a

desi

gnat

ed s

ite,

or

infr

astr

uctu

re b

etw

een

two

desi

gnat

ed s

ites

Sev

eran

ce o

f an

app

roac

h to

/ or

set

ting

of/

or w

ithin

an

his

toric

land

scap

e

Sev

eran

ce o

f ac

cess

ro

ute,

e.g

. na

tiona

l or

regi

onal

tra

il, c

ycle

rou

te

or b

ridl

eway

Sev

eran

ce o

f sp

ecie

s co

mm

utin

g ro

utes

(e.

g.

bats

)

Infr

astr

uctu

re t

o be

site

d w

ithin

a s

tatu

tory

de

sign

ated

land

scap

e (e

.g.

Nat

iona

l Par

k or

AO

NB)

Sev

eran

ce o

f tw

o ar

eas

of

publ

ic o

pen

spac

e

Sev

eran

ce o

f ra

re

habi

tats

or

habi

tats

of

loca

l im

port

ance

Sev

eran

ce o

f a

high

ly

valu

ed o

r se

nsiti

ve

feat

ure

of im

port

ance

to

land

scap

e ch

arac

ter

(e.g

. sm

all l

anes

) or

to

addr

ess

othe

r la

ndsc

ape

Sev

eran

ce b

etw

een

resi

dent

ial a

reas

and

gr

eens

pace

or

rura

l are

as

Eco

log

ical

La

nd

scap

e A

cces

s

seve

ranc

e/co

nnec

tivity

is

sues

(e.

g. t

o av

oid

an

unbr

oken

sky

line)

Iden

tific

atio

n of

loca

l bi

odiv

ersi

ty b

enef

its t

hat

a gr

een

brid

ge c

ould

pr

ovid

e, e

.g. co

nnec

ting

loca

l wild

life

site

s

Iden

tific

atio

n of

loca

l la

ndsc

ape

bene

fits

that

a

gree

n br

idge

cou

ld

prov

ide,

e.g

. cr

eatin

g an

ic

onic

str

uctu

re (

in

keep

ing

with

land

scap

e ch

arac

ter)

Iden

tific

atio

n of

acc

ess

bene

fits

that

a g

reen

br

idge

cou

ld p

rovi

de, e.

g.

addr

essi

ng lo

cal

defic

ienc

ies

in a

cces

s to

gr

eens

pace

thr

ough

lin

king

to

publ

ic r

ight

s of

w

ay a

nd o

ther

gr

eens

pace

s

Wid

er B

enef

its

Gree

n br

idge

s m

ay b

e ab

le t

o pr

ovid

e a

rang

e of

ben

efits

bey

ond

that

of

thei

r in

itial

driv

ers.

For

exa

mpl

e th

e m

ain

driv

ers

of a

pro

ject

may

be

to

prov

ide

acce

ss a

nd b

y ad

ding

gre

en f

eatu

res

to a

brid

ge a

pro

ject

can

de

liver

add

ition

al f

unct

ions

. A

mix

ed u

se g

reen

brid

ge c

an p

rovi

de w

ider

ec

osys

tem

ser

vice

s su

ch a

s cu

ltura

l se

rvic

es,

allo

win

g fo

r re

crea

tiona

l ac

tiviti

es b

y jo

inin

g up

a s

ever

ed p

ath

and

prov

idin

g cu

ltura

l ser

vice

s in

re

latio

n to

aes

thet

ic v

alue

s and

cre

atin

g a

sens

e of

pla

ce.

Inco

rpor

atin

g st

ruct

ures

suc

h as

gre

en b

ridge

s in

to s

chem

e de

sign

to

addr

ess

ecol

ogic

al, l

ands

cape

and

acc

ess

seve

ranc

e is

in li

ne w

ith a

num

ber

of g

over

nmen

t pol

icy

docu

men

ts in

clud

ing:

� th

e N

atio

nal P

olic

y Fr

amew

ork

(NPP

F) w

hich

iden

tifie

s th

e ne

ed

to m

inim

ise im

pact

s on

bio

dive

rsity

whi

le p

rovi

ding

net

gai

ns

whe

re p

ossib

le.

It al

so d

etai

ls th

at l

ocal

pla

nnin

g au

thor

ities

sh

ould

set o

ut a

stra

tegi

c ap

proa

ch in

thei

r Loc

al P

lans

, pla

nnin

g po

sitiv

ely

for

the

crea

tion,

pr

otec

tion,

en

hanc

emen

t an

d m

anag

emen

t of

ne

twor

ks

of

biod

iver

sity

and

gree

n

Page 6: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

4

infr

astr

uctu

re a

nd a

dvoc

ates

a l

ands

cape

sca

le a

ppro

ach

to

biod

iver

sity.

With

res

pect

to

acce

ss,

the

NPP

F de

tails

tha

t pl

anni

ng p

olic

ies

shou

ld p

rote

ct a

nd e

nhan

ce p

ublic

rig

hts

of

way

and

acc

ess.

With

res

pect

to

land

scap

e it

iden

tifie

s th

e im

port

ance

of

pr

otec

ting

and

enha

ncin

g va

lued

la

ndsc

apes

, an

d th

e w

eigh

t sh

ould

be

give

n to

con

serv

ing

land

scap

e an

d sc

enic

be

auty

in

N

atio

nal

Park

s,

the

Bro

ads

and

Are

as

of

Out

stan

ding

Nat

ural

Bea

uty

� th

e N

atio

nal

Net

wor

ks N

atio

nal

Polic

y Sta

tem

ent,

whi

ch c

ites

gree

n br

idge

s as

a w

ay o

f en

hanc

ing

exis

ting

habi

tats

and

cr

eatin

g ne

w h

abita

ts o

f va

lue.

� th

e N

atur

al E

nviro

nmen

t W

hite

Pap

er w

hich

aim

s to

est

ablis

h co

here

nt e

colo

gica

l net

wor

ks th

at a

re m

ore

resil

ient

to c

urre

nt

and

futu

re p

ress

ures

.

� th

e N

atur

al E

nviro

nmen

t an

d Ru

ral

Com

mun

ities

(N

ERC)

Act

20

06, w

hich

det

ails

that

“Eve

ry p

ublic

aut

horit

y m

ust,

in e

xerc

ising

its

fun

ctio

ns,

have

re

gard

, so

far

as

is co

nsist

ent

with

the

pro

per

exer

cise

of

thos

e fu

nctio

ns,

to t

he p

urpo

se o

f co

nser

ving

bio

dive

rsity

” Se

ctio

n 40

, N

ERC

Act,

2006

Oth

er k

ey d

ocum

ents

inc

lude

Law

ton’

s M

akin

g Sp

ace

for

Nat

ure

(201

0).

This

repo

rt p

rovi

des

an in

depe

nden

t re

view

of E

ngla

nd’s

wild

life

sites

and

th

e co

nnec

tions

bet

wee

n th

em a

long

with

rec

omm

enda

tions

to

help

ac

hiev

e a

heal

thy

natu

ral e

nviro

nmen

t. T

he r

epor

t id

entif

ies

the

need

for

grea

ter

join

ed u

p th

inki

ng a

nd p

rovi

sions

of

conn

ectio

ns a

cros

s ou

r la

ndsc

ape

for

wild

life

to f

unct

ion.

La

wto

n id

entif

ies

that

“th

e es

senc

e of

w

hat

need

s to

be

done

to

enha

nce

the

resil

ienc

e an

d co

here

nce

of

Engl

and’

s ec

olog

ical

net

wor

k ca

n be

sum

mar

ised

in f

our

wor

ds:

mor

e,

bigg

er, b

ette

r and

join

ed”.

O

ne o

f the

five

key

app

roac

hes i

dent

ified

in th

e re

view

is to

enh

ance

con

nect

ions

bet

wee

n, o

r jo

in u

p, s

ites,

eith

er th

roug

h ph

ysic

al c

orrid

ors,

or t

hrou

gh ‘s

tepp

ing

ston

es’.

Gree

n br

idge

s ca

n be

a k

ey

step

in a

chie

ving

this

visio

n to

prio

ritise

bio

dive

rsity

net

wor

ks.

Alte

rnat

ives

to g

reen

brid

ges

It is

impo

rtan

t to

ens

ure

that

miti

gatio

n an

d en

hanc

emen

t m

easu

res

are

prop

ortio

nate

. Gr

een

brid

ges

are

one

of a

num

ber o

f mea

sure

s th

at c

ould

be

con

sider

ed to

add

ress

eco

logi

cal,

land

scap

e an

d ac

cess

seve

ranc

e iss

ues.

As

par

t of

the

con

sider

atio

n of

opt

ions

it m

ay b

e ne

cess

ary

to c

onsid

er

alte

rnat

ive

optio

ns, w

hich

may

incl

ude

the

follo

win

g:

- M

odifi

ed g

rey

brid

ges

- M

ultif

unct

iona

l ove

rpas

ses

- Cu

t and

cov

er tu

nnel

s -

Pede

stria

n, c

yclis

t and

equ

estr

ian

brid

ges

- U

nder

pass

es fo

r med

ium

-size

d an

d la

rge

anim

als

- U

nder

pass

es fo

r sm

all a

nim

als

- M

odifi

ed a

nd m

ultif

unct

iona

l und

erpa

sses

-

Mod

ified

cul

vert

s -

Fish

pas

sage

s -

Amph

ibia

n tu

nnel

s -

Fenc

es (e

.g. w

here

mam

mal

col

lisio

ns a

re a

key

con

sider

atio

n)

- W

arni

ng si

gns/

war

ning

syst

ems w

ith se

nsor

s -

Clea

ring

vege

tatio

n/ P

lant

ing

vege

tatio

n

- Es

cape

ram

ps fr

om d

rain

s, fa

una

exits

in w

ater

way

s -

Artif

icia

l lig

htin

g (e

.g.

to d

eter

spe

cies

fro

m c

ross

ing

in a

ce

rtai

n ar

ea)

Whe

n pl

anni

ng a

gre

en b

ridg

e, t

his

shou

ld n

ot b

e do

ne in

is

olat

ion,

but

sho

uld

form

par

t of

a w

ider

and

inte

grat

ed

desi

gn a

nd m

itiga

tion

stra

tegy

add

ress

ing

wild

life,

la

ndsc

ape,

acc

ess

and

broa

der

ecos

yste

m s

ervi

ces

cons

ider

atio

ns.

Par

ticul

arly

of re

leva

nce

for

long

line

ar

sche

mes

a g

reen

bri

dge

may

be

used

in c

ombi

natio

n w

ith u

nder

pass

es,

tunn

els

and

ledg

es t

o in

crea

se t

he

perm

eabi

lity

of t

he r

oad

or r

ailw

ay t

o w

ildlif

e.

Page 7: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

5

Re

cord

ing

Aim

s and

Obj

ectiv

es

If th

e ea

rly s

chem

e pl

anni

ng s

tage

s id

entif

y th

at a

gre

en b

ridge

cou

ld

prov

ide

a m

itiga

tion

solu

tion,

it is

impo

rtan

t tha

t the

aim

s and

obj

ectiv

es o

f co

nstr

uctin

g a

gree

n br

idge

are

cle

arly

reco

rded

.

As t

he p

roje

ct p

rogr

esse

s th

e ai

ms

and

obje

ctiv

es s

houl

d be

reg

ular

ly

revi

sited

and

upd

ated

in

the

light

of

any

new

inf

orm

atio

n, i

.e.

data

ga

ther

ed t

hrou

gh s

urve

ys, s

take

hold

er c

onsu

ltatio

n.

It is

impo

rtan

t th

at

robu

st d

ata

is co

llect

ed a

t ea

rly s

tage

s so

thi

s ca

n be

com

pare

d w

ith t

he

findi

ngs

post

con

stru

ctio

n an

d sh

ould

be

tied

into

the

futu

re m

anag

emen

t an

d m

aint

enan

ce p

lan

post

con

stru

ctio

n.

.

Furt

her

gu

idan

ce o

n a

lter

nat

ives

can

be

fou

nd

wit

hin

th

e fo

llow

ing

sou

rces

:

Des

ign

Man

ual f

or R

oads

and

Bridg

es,

Vol

ume

10 (

sect

ions

3 a

nd 4

) Vo

lum

e 11

(se

ctio

ns 3

and

4)

Gre

at C

rest

ed N

ewt

Miti

gatio

n G

uide

lines

(En

glis

h N

atur

e 20

01)

Bat

Miti

gatio

n G

uide

lines

(En

glis

h N

atur

e 20

04)

The

Dor

mou

se C

onse

rvat

ion

Han

dboo

k 2nd

Edi

tion

(Eng

lish

Nat

ure

2006

)

Wat

er V

ole

Con

serv

atio

n H

andb

ook

3rd E

ditio

n (S

trac

han

2011

)

Com

mon

Toa

ds a

nd R

oads

: G

uida

nce

for

high

way

s pl

anne

rs a

nd e

ngin

eers

in

Engl

and

(ARC 2

011)

Gui

danc

e on

Bui

ldin

g D

evel

opm

ent

(Eng

land

) W

ith R

espe

ct t

o Am

phib

ians

and

Rep

tiles

, Am

phib

ian

and

Rep

tile

Con

serv

atio

n, S

ep 2

010

Page 8: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

6

Pla

nn

ing

for

a g

reen

bri

dg

e st

ruct

ure

Whe

n pl

anni

ng fo

r a g

reen

brid

ge, i

t is

impo

rtan

t tha

t thi

s is

incl

uded

with

th

e ea

rly d

esig

n st

ages

. Th

is is

to a

llow

suf

ficie

nt s

urve

ys to

be

unde

rtak

en

to p

rovi

de a

pre

-con

stru

ctio

n ba

se l

ine

as w

ell

as t

o al

low

for

wid

er

cons

ulta

tion

to ta

ke p

lace

and

to e

nsur

e th

at th

e de

sign

is fu

lly in

tegr

ated

in

to t

he w

ider

tra

nspo

rt n

etw

ork

and

surr

ound

ing

land

scap

e an

d is

appr

opria

tely

loca

ted.

It is

reco

mm

ende

d th

at t

he fo

llow

ing

step

s ar

e ta

ken

durin

g th

e pl

anni

ng

proc

ess:

Step

1: D

evel

op a

Com

mun

icat

ion

Plan

In

or

der

to

enga

ge

with

st

akeh

olde

rs

it is

reco

mm

ende

d th

at

a co

mm

unic

atio

n pl

an is

dev

elop

ed a

t th

e pr

ojec

t ou

tset

. Th

is sh

ould

hel

p sm

ooth

the

con

sent

ing

proc

ess.

Th

e co

mm

unic

atio

n pl

an s

houl

d co

ntai

n th

e fo

llow

ing

actio

ns:

- Es

tabl

ish a

div

erse

pro

ject

stee

ring

com

mitt

ee w

ith b

road

re

pres

enta

tion

incl

udin

g: l

ocal

aut

horit

y, l

ocal

com

mun

ity g

roup

s, l

ocal

w

ildlif

e gr

oups

, lo

cal

acce

ss

grou

ps,

proj

ect

neig

hbou

rs,

stat

utor

y co

nsul

tees

. -

Enco

urag

e an

d re

cord

sta

keho

lder

/par

ticip

ant

cont

ribut

ions

fro

m p

ublic

m

eetin

gs,

- De

velo

p a

com

mun

icat

ion

plan

to p

ublic

ise m

eetin

gs a

nd w

orks

hops

in lo

cal

and

regi

onal

med

ia,

- M

aint

ain

a vi

sible

, acc

essib

le p

ublic

reco

rd in

clud

ing

mee

ting

and

wor

ksho

p m

inut

es t

o as

sure

tha

t in

form

atio

n an

d co

mm

ents

are

par

t of

the

offi

cial

pr

ojec

t rec

ord/

proc

ess,

-

Mai

ntai

n an

up-

to-d

ate

proj

ect w

ebsit

e, in

clud

ing:

pro

ject

su

mm

ary,

sch

edul

e, c

onta

ct i

nfor

mat

ion,

dow

nloa

dabl

e dr

aft

docu

men

ts,

map

s and

imag

es, a

nd a

ddre

ss fo

r em

ail.

Step

2: I

nfor

mat

ion

Gath

erin

g In

ord

er t

o de

cide

on

the

best

loca

tion

to p

ositi

on a

gre

en b

ridge

a w

ide

rang

e of

inf

orm

atio

n sh

ould

be

colle

cted

. I

t is

reco

mm

ende

d th

at t

his

info

rmat

ion

is th

en o

verla

id in

Geo

grap

hica

l Inf

orm

atio

n Sy

stem

(GIS

).

The

follo

win

g in

form

atio

n sh

ould

be

colle

cted

:

- Ae

rial p

hoto

grap

hy

- La

ndow

ners

hip

map

s and

adj

acen

t lan

d m

anag

emen

t -

Pote

ntia

l fut

ure

chan

ges i

n la

nd m

anag

emen

t -

Land

scap

e Ch

arac

ter A

sses

smen

ts

- Ph

ase

1 ha

bita

t m

aps

(and

w

here

ap

prop

riate

N

atio

nal

Vege

tatio

n Cl

assif

icat

ion

map

s)

- Gr

eens

pace

and

gre

en in

fras

truc

ture

map

s sh

owin

g pu

blic

acc

ess

incl

udin

g op

en a

cces

s, c

omm

on la

nd e

tc.

- De

finiti

ve M

ap o

f Pub

lic R

ight

s of W

ay

- Am

enity

use

-

Road

kill

dat

a -

Topo

grap

hy d

ata

- Ge

olog

y da

ta

- Fl

ood

risk

zone

-

Util

ities

-

Loca

l bio

dive

rsity

opp

ortu

nity

map

s -

Loca

l st

rate

gies

an

d m

anag

emen

t pl

ans

e.g.

pr

otec

ted

land

scap

e m

anag

emen

t pl

ans,

gre

en in

fras

truc

ture

/op

en s

pace

str

ateg

ies

and

plan

s,

loca

l bio

dive

rsity

act

ion

plan

s -

Desig

nate

d na

ture

con

serv

atio

n sit

es, p

rote

cted

land

scap

es a

nd p

rote

cted

sp

ecie

s inf

orm

atio

n

This

data

gat

herin

g pr

oces

s is

likel

y to

requ

ire s

urve

ys to

be

unde

rtak

en.

It is

impo

rtan

t th

at t

hese

sur

veys

are

und

erta

ken

in a

sys

tem

atic

and

re

peat

able

way

. S

urve

ys s

houl

d fo

llow

bes

t pr

actic

e gu

idel

ines

and

ful

l su

rvey

resu

lts s

houl

d be

pre

sent

ed.

For s

ome

spec

ies

(for e

xam

ple

bats

) it

is no

ted

that

tw

o ye

ars

of s

urve

y da

ta m

ay b

e re

quire

d to

pro

vide

rob

ust

indi

catio

n of

site

use

; thi

s sho

uld

be c

onsid

ered

in p

roje

ct ti

mes

cale

s.

Page 9: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

7

Step

3: C

hoos

ing

a lo

catio

n U

sing

the

data

iden

tifie

d ab

ove,

a s

hort

list

of l

ocat

ions

sho

uld

be c

reat

ed.

Whe

n sit

ing

a br

idge

, con

sider

atio

n ne

eds

to b

e gi

ven

to a

reas

bey

ond

a pr

ojec

t’s im

med

iate

bou

ndar

y to

iden

tify

optim

um lo

catio

ns a

t a la

ndsc

ape

scal

e. T

his

appr

oach

is n

eede

d to

ens

ure

that

brid

ges

deliv

er th

e gr

eate

st

poss

ible

ben

efits

.

Onc

e a

shor

t lis

t ha

s be

en c

reat

ed t

his

shou

ld b

e su

bjec

t to

fur

ther

sc

reen

ing

base

d on

topo

grap

hy, o

bsta

cles

pre

sent

, geo

logy

and

geo

grap

hy,

mai

nten

ance

, sa

fety

, flo

od r

isk a

nd u

tiliti

es a

ll of

whi

ch c

an u

ltim

atel

y in

fluen

ce t

he lo

catio

n.

Whe

n sit

ing

a gr

een

brid

ge t

he la

ndsc

ape

cont

ext

and

loca

l lan

dsca

pe c

hara

cter

shou

ld b

e co

nsid

ered

.

Key

poin

ts w

hich

shou

ld b

e co

nsid

ered

whe

n se

lect

ing

a lo

catio

n ar

e:

- O

utco

mes

of

co

nsul

tatio

n w

ith

stat

utor

y co

nsul

tees

, en

viro

nmen

tal

part

ners

hips

, loc

al c

omm

uniti

es, l

and

owne

rs a

nd o

ther

rele

vant

par

ties.

-

Avoi

d ar

eas

with

larg

e di

ffere

nces

in to

pogr

aphy

(bet

wee

n le

vel g

roun

d an

d em

bank

men

ts);

this

is lik

ely

to b

e es

peci

ally

im

port

ant

whe

n ad

dres

sing

land

scap

e se

vera

nce.

-

Whe

re t

arge

t sp

ecie

s re

ly o

n a

habi

tat,

sele

ct a

site

whe

re t

he h

abita

t ca

n be

con

nect

ed to

the

brid

ge.

- If

targ

etin

g sp

ecie

s use

, loc

ate

alon

g tr

aditi

onal

com

mut

ing

rout

es

- W

hen

plan

ning

a b

ridge

for

wild

life

use,

con

sider

if a

mix

ed u

se b

ridge

is

appr

opria

te in

term

s of d

istur

banc

e le

vels.

Con

sider

sel

ectin

g lo

catio

ns w

ith

low

lev

els

of h

uman

dist

urba

nce,

tak

ing

acco

unt

of

futu

re p

ropo

sed

deve

lopm

ent.

- Do

n’t

crea

te ‘

dead

end

s’ i.

e. d

on’t

build

a b

ridge

to

now

here

, th

e br

idge

ne

eds t

o co

nnec

t int

o a

wid

er p

erm

eabl

e la

ndsc

ape

- Co

nsid

er t

he lo

catio

n of

oth

er f

eatu

res

in t

he la

ndsc

ape

that

can

enh

ance

co

nnec

tivity

an

d ho

w

the

brid

ge

loca

tion

inte

ract

s w

ith

thes

e i.e

. w

ater

cour

ses,

hed

ge li

nes,

gre

enw

ays,

par

ks a

nd g

reen

spac

es, s

ites e

tc.

- Fo

r a

mix

ed u

se b

ridge

con

sider

con

nect

ions

with

str

ateg

ic a

cces

s ro

utes

su

ch a

s pu

blic

rig

hts

of w

ay, N

atio

nal T

rails

, str

ateg

ic c

ycle

net

wor

k, h

orse

rid

ing

trai

ls an

d ot

her l

ocal

acc

ess r

oute

s

Step

4: S

peci

fic D

esig

n Co

nsid

erat

ions

Th

e ov

eral

l fun

ctio

n of

the

gree

n br

idge

will

driv

e m

ost o

f the

dec

ision

s, a

s th

e siz

e of

the

stru

ctur

e m

ust b

e de

term

ined

bas

ed o

n th

e re

quire

men

ts o

f th

e ex

pect

ed u

se (i

.e. s

peci

es s

peci

fic, m

ixed

etc

.) an

d th

e de

gree

of n

eed

for s

epar

atio

n be

twee

n w

ildlif

e an

d hu

man

acc

ess.

Onc

e th

e pr

efer

red

loca

tion

for

the

gree

n br

idge

has

bee

n se

lect

ed th

en a

lis

t of

spe

cific

des

ign

cons

ider

atio

ns s

houl

d be

cre

ated

to

allo

w t

he m

ost

suita

ble

type

of s

truc

ture

to b

e se

lect

ed.

Spec

ific

desig

n co

nsid

erat

ions

will

nee

d to

take

acc

ount

of t

he fo

llow

ing:

- Ex

istin

g an

d pr

opos

ed l

evel

of

the

road

in

rela

tion

to t

he s

urro

undi

ng

land

scap

e -

Shap

e of

gre

en b

ridge

, e.g

. hou

rgla

ss o

r str

aigh

t -

Wid

th

- Le

ngth

-

Suita

ble

vege

tatio

n to

be

in k

eepi

ng w

ith lo

cal l

ands

cape

and

hab

itats

-

Soil

dept

h an

d su

bstr

ate

type

-

Scre

enin

g an

d fe

ncin

g -

Targ

et sp

ecie

s -

Oth

er u

sers

(ped

estr

ians

, equ

estr

ian,

cyc

lists

); ac

cess

for a

ll -

Ecos

yste

m

serv

ices

be

nefit

s (s

uch

as

polli

natio

n,

cultu

ral

herit

age,

re

crea

tion

and

tour

ism,

aest

hetic

exp

erie

nce,

wat

er m

anag

emen

t, w

ild

spec

ies d

iver

sity)

-

Engi

neer

ing

cons

ider

atio

ns

- Dr

aina

ge a

nd w

ater

(for

exa

mpl

e, p

onds

) -

Ease

and

cos

t of m

aint

enan

ce/m

anag

emen

t -

Abili

ty o

f w

ildlif

e to

acc

ess

and

exit

from

the

brid

ge in

to t

he s

urro

undi

ng

land

scap

e -

Ligh

ting

- Co

nnec

tivity

with

sur

roun

ding

fea

ture

s in

the

wid

er l

ands

cape

i.e

. fo

r w

ildlif

e br

idge

s, v

eget

atio

n w

ill n

eed

to c

onne

ct in

to s

urro

undi

ng la

ndsc

ape

feat

ures

such

as w

ater

cour

ses,

hed

ge li

nes.

Page 10: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

8

[Spe

cific

Des

ign

Con

side

ration

s co

ntin

ued:

] W

idth

an

d l

eng

th

Brid

ges

aim

ing

to a

chie

ve c

onne

ctio

ns a

t a

land

scap

e/ e

cosy

stem

lev

el

shou

ld b

e ov

er 8

0m in

wid

th.

Brid

ges

aim

ing

to a

chie

ve c

onne

ctio

ns f

or

spec

ies

at a

pop

ulat

ion

leve

l sho

uld

be a

roun

d 50

m (

publ

ished

gui

danc

e re

com

men

datio

ns ra

nge

from

25m

-80m

, with

an

aver

age

of 5

0m).

Brid

ges

belo

w 2

0m in

wid

th a

re n

ot r

ecom

men

ded

as f

requ

ency

of

use

has

been

fo

und

to b

e lo

wer

. Th

e le

ngth

will

larg

ely

be d

eter

min

ed b

y th

e nu

mbe

r of

road

s/ ra

ilway

line

s th

at a

re c

ross

ed.

The

leng

th w

ill a

lso b

e in

fluen

ced

by

topo

grap

hy a

s the

acc

ess r

amps

shou

ld n

ot b

e to

o st

eep.

A w

idth

to le

ngth

ra

tio o

ver 0

.8 is

reco

mm

ende

d.

Veg

etat

ion

The

vege

tatio

n sh

ould

co

mpl

emen

t th

e ha

bita

ts

eith

er

side

of

the

stru

ctur

e, u

sing

plan

t spe

cies

nat

ive

to th

e lo

cal a

rea.

In

term

s of

see

ding

, op

tions

inc

ludi

ng n

atur

al e

stab

lishm

ent

and

use

of t

he l

ocal

see

d ba

nk

(from

top

soil

or h

ay c

uttin

g) s

houl

d be

con

sider

ed.

Hedg

e st

ruct

ures

can

be

use

d to

pro

vide

a g

uidi

ng li

ne, f

or s

peci

es s

uch

as b

ats,

and

sho

uld

be

cont

inuo

us a

nd c

onne

ct w

ith e

stab

lishe

d fo

ragi

ng r

oute

s. W

hen

targ

etin

g sm

all v

erte

brat

es a

nd in

vert

ebra

tes t

hen

the

aim

shou

ld b

e to

rese

mbl

e th

e ha

bita

t adj

acen

t to

the

brid

ge a

s fa

r as

is po

ssib

le.

The

plan

ting

shou

ld b

e de

signe

d to

cre

ate

a m

osai

c w

ith tr

ee a

nd sh

rub

plan

ting

at th

e en

d an

d th

e m

iddl

e se

ctio

n le

ft op

en w

ith g

rass

es a

nd s

mal

ler

vege

tatio

n.

Depe

ndin

g on

the

spec

ies

that

may

use

the

brid

ge it

may

also

be

appr

opria

te to

leav

e pa

tche

s of

bar

e gr

ound

or

grav

el.

If su

ch m

icro

-hab

itats

are

cre

ated

the

n w

ithin

the

man

agem

ent

plan

mea

sure

s sh

ould

be

incl

uded

to

ensu

re t

hat

thes

e re

mai

n op

en a

reas

rat

her

than

allo

win

g co

loni

satio

n by

veg

etat

ion.

Br

ash,

tre

e st

umps

and

pile

s of

rub

ble

may

also

be

used

to

crea

te r

efug

es

for s

mal

l ani

mal

s.

To a

ccou

nt fo

r th

e tim

e it

take

s fo

r ve

geta

tion

to e

stab

lish,

oth

er fe

atur

es

may

be

need

ed t

o pr

ovid

e co

ver

follo

win

g br

idge

con

stru

ctio

n.

This

may

in

clud

e tr

ee s

tum

ps, p

iles

of b

rash

and

sto

nes

(it m

ay b

e po

ssib

le t

o us

e

left

over

con

stru

ctio

n m

ater

ials

for

this

purp

ose)

, as

wel

l pl

antin

g m

ore

mat

ure

shru

b, h

edge

and

tree

sapl

ings

.

Wat

er fe

atur

es c

an b

e cr

eate

d on

brid

ges

to p

rovi

de “

step

ping

sto

nes”

for

spec

ies

usin

g th

e br

idge

and

can

also

pro

vide

a h

abita

t in

the

ir ow

n rig

ht.

Thes

e ha

ve b

een

succ

essf

ully

cre

ated

on

the

cont

inen

t an

d us

ed b

y a

num

ber

of a

mph

ibia

n sp

ecie

s an

d dr

agon

flies

. T

his

can

be a

chie

ved

by

crea

ting

a se

ries

of w

et d

epre

ssio

ns a

cros

s th

e br

idge

itse

lf, w

ith d

eepe

r po

nds e

ither

side

. W

ater

recy

clin

g ca

n be

use

d to

tran

spor

t rai

n w

ater

run-

of

f to

the

top

of th

e br

idge

, whi

ch c

an th

en ru

n do

wn

the

brid

ge th

roug

h a

serie

s of

sm

all p

ools/

wet

dep

ress

ions

. It

is no

ted

that

the

wet

hab

itats

on

the

brid

ge d

o no

t nee

d to

con

tain

wat

er a

t all

times

, and

will

be

depe

nden

t on

rain

wat

er.

Soi

l

The

amou

nt o

f soi

l use

d w

ill a

ffect

the

brid

ge lo

ad.

It m

ay b

e po

ssib

le t

o ac

hiev

e de

eper

dep

ths

at th

e ed

ges

of th

e br

idge

with

sha

llow

dep

th in

the

cent

re.

The

var

iatio

n in

soi

l de

pths

can

be

used

to

crea

te a

mos

aic

of

vege

tatio

n, i

nclu

ding

mai

ntai

ning

are

as o

f ba

re g

roun

d, a

nd c

reat

ing

a va

ried

topo

grap

hy.

As a

gui

de th

e fo

llow

ing

dept

hs m

ight

be

appr

opria

te:

Gras

s and

her

bs: 0

.3m

, Shr

ubs:

0.6

m, T

rees

: 1.5

m.

In s

ome

case

s to

p so

il m

ay n

ot b

e re

quire

d, d

epen

ding

on

the

targ

et

vege

tatio

n, f

or e

xam

ple

crus

hed

aggr

egat

e m

ay b

e us

ed t

o cr

eate

a

subs

trat

e su

itabl

e fo

r spe

cies

ass

ocia

ted

with

bro

wn

field

site

s.

Advi

ce fr

om a

n en

gine

er sh

ould

be

soug

ht if

nec

essa

ry.

Scr

een

ing

an

d f

enci

ng

Scre

ens

can

be u

sed

to r

educ

e di

stur

banc

e on

the

brid

ge f

rom

ligh

t an

d no

ise.

Thes

e sh

ould

be

loca

ted

as c

lose

to th

e ou

ter e

dge

of th

e br

idge

as

poss

ible

to m

axim

ise th

e am

ount

of t

he b

ridge

ava

ilabl

e fo

r use

.

On

wid

er b

ridge

s, h

edge

s on

mou

nds

may

be

used

to

prov

ide

scre

enin

g.

Whe

re e

arth

mou

nds

are

used

the

se s

houl

d be

des

igne

d to

ext

end

alon

g th

e tr

ansp

ort

infr

astr

uctu

re.

Side

scr

eens

sho

uld

be a

roun

d 2m

in h

eigh

t an

d sh

ould

be

conn

ecte

d in

to a

ny o

ther

scr

eeni

ng p

rese

nt a

long

the

in

fras

truc

ture

(suc

h as

noi

se b

arrie

rs).

If s

cree

ns a

re n

ot u

sed

then

fenc

ing

Page 11: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

9

mus

t be

pla

ced

alon

g th

e ou

ter

edge

of

the

brid

ge a

nd f

enci

ng o

n th

e br

idge

mus

t tie

into

fenc

ing

alon

g th

e in

fras

truc

ture

.

Lig

hti

ng

If th

e m

ain

driv

er o

f the

brid

ge is

wild

life

use

then

it is

reco

mm

ende

d th

at

light

ing

is av

oide

d.

If a

mix

ed u

se b

ridge

is

desig

ned,

whe

re l

ight

ing

is re

quire

d, t

his

shou

ld b

e de

signe

d to

min

imise

dist

urba

nce

to w

ildlif

e.

Guid

ance

on

the

Ba

t Co

nser

vatio

n Tr

ust

web

site

shou

ld

cons

ider

ed:

http

://w

ww

.bat

s.or

g.uk

/pag

es/b

ats_

and_

light

ing.

htm

l

Targ

et s

pec

ies

The

targ

et s

peci

es fo

r us

e m

ay b

e cr

itica

l in

dete

rmin

ing

the

wid

th, d

esig

n an

d ve

geta

tion.

For

exa

mpl

es a

mph

ibia

ns m

ay re

quire

a “

wet

zone

” ac

ross

th

e br

idge

. F

or l

arge

r an

imal

s, t

he w

idth

and

loc

atio

n ca

n be

mor

e im

port

ant

than

the

veg

etat

ion,

but

for

sm

alle

r an

imal

s su

ch a

s ba

ts t

he

vege

tatio

n is

mor

e im

port

ant.

Oth

er U

sers

(M

ixed

use

)

In g

ener

al t

he li

tera

ture

focu

ses

on b

ridge

s w

ith a

wild

life

func

tion

and

as

such

gui

danc

e re

com

men

ds a

void

ing

mix

ed u

se s

truc

ture

s w

here

wild

life

use

is th

e pr

imar

y ob

ject

ive.

How

ever

in tw

o st

udie

s on

mix

ed u

se b

ridge

s, w

here

wild

life

use

was

inve

stig

ated

, evi

denc

e of

spe

cies

use

was

reco

rded

an

d as

suc

h it

is co

nsid

ered

in c

erta

in c

ircum

stan

ces,

mix

ed u

se b

ridge

s m

ay b

e ap

prop

riate

.

At t

he Z

ande

rij C

railo

o gr

een

brid

ge i

n Ho

lland

re

cord

ed 1

80,0

00 w

alke

rs a

nd c

yclis

ts a

nd 1

7,00

0 ho

rse

rider

s in

a y

ear a

nd

13

spec

ies

wer

e re

cord

ed

usin

g th

e br

idge

, in

clud

ing

6 sp

ecie

s of

am

phib

ians

and

2 sp

ecie

s rep

tiles

.

To d

eter

min

e th

e w

idth

of

a m

ixed

use

brid

ge,

the

wid

th o

f an

y pa

ths

shou

ld b

e ad

ded

to th

e w

idth

req

uire

d fo

r fa

unal

pas

sage

to g

ive

the

tota

l w

idth

of t

he b

ridge

.

For b

ridge

s, w

here

the

mai

n ob

ject

ive

is sp

ecie

s use

(par

ticul

arly

for s

peci

es

sens

itive

to d

istur

banc

e) it

is re

com

men

ded

that

any

pat

hs u

sed

shou

ld b

e po

sitio

ned

on a

n ou

ter

edge

to

ensu

re t

he w

idth

of

the

natu

ral

area

is

reta

ined

. W

here

the

mai

n fu

nctio

n is

to p

rovi

de a

cces

s, w

ith a

sec

onda

ry

biod

iver

sity

bene

fit, t

hen

it m

ay b

e ap

prop

riate

to c

onsid

er th

e us

e of

pat

hs

in o

ther

are

as o

f the

brid

ge. T

he n

eeds

of p

eopl

e of

all

abili

ties

shou

ld b

e co

nsid

ered

to e

nsur

e ac

cess

for a

ll.

If gr

eeni

ng a

low

use

roa

d br

idge

(e.

g. a

n ac

com

mod

atio

n ov

erbr

idge

), a

vege

tate

d st

rip a

long

one

edg

e m

ay b

e us

ed.

This

shou

ld h

ave

a m

inim

um

wid

th o

f 1m

, with

soil

of a

roun

d 0.

3m (a

gain

this

may

dep

end

on th

e ta

rget

ve

geta

tion

and

it m

ay b

e po

ssib

le t

o us

ed c

rush

ed a

ggre

gate

). T

he s

trip

m

ay b

e pl

ante

d or

left

to n

atur

ally

veg

etat

e, a

lthou

gh it

is im

port

ant t

hat a

m

anag

emen

t pl

an is

in p

lace

to

ensu

re t

hat

the

verg

e is

wel

l mai

ntai

ned.

Ap

prop

riate

in

form

atio

n an

d in

terp

reta

tion

will

ad

d to

us

ers’

unde

rsta

ndin

g an

d ap

prec

iatio

n of

the

gree

n br

idge

.

Ecos

yste

m s

ervi

ce b

enef

its

In d

esig

ning

a g

reen

brid

ge c

onsid

erat

ion

shou

ld a

lso b

e gi

ven

to w

hat

ecos

yste

m s

ervi

ces

the

stru

ctur

e ca

n pr

ovid

e.

For

mos

t br

idge

s, i

f th

e de

sign

is fo

r wild

life

purp

oses

or h

as a

seco

ndar

y w

ildlif

e fu

nctio

n, th

en th

e br

idge

w

ill

natu

rally

pr

ovid

e th

e fu

nctio

n of

w

ild

spec

ies

dive

rsity

.

Exam

ples

of o

ther

eco

syst

em se

rvic

es th

at m

ay b

e pr

ovid

ed in

clud

e th

e us

e of

pla

nt s

peci

es w

ith h

igh

nect

ar s

ourc

es t

o pr

ovid

e a

reso

urce

for

po

llina

ting

inse

cts;

thi

s m

ay b

e ac

hiev

ed t

hrou

gh p

lant

ing

a w

ildflo

wer

m

eado

w m

ix o

f loc

al p

rovi

denc

e or

thro

ugh

loca

l sel

f-see

ding

.

The

met

hod

of d

rain

age

shou

ld a

lso c

onsid

er w

ater

recy

clin

g to

irrig

ate

the

brid

ge s

truc

ture

. Th

is m

ay a

lso b

e us

ed t

o pr

ovid

e re

silie

nce

to c

limat

e ch

ange

, for

exa

mpl

e by

usin

g ba

sins

with

in th

e br

idge

dec

k to

reta

in w

ater

fo

r use

in d

roug

ht p

erio

ds.

Mix

ed u

se b

ridge

s an

d th

ose

that

are

des

igne

d to

mai

ntai

n cu

ltura

l and

re

crea

tiona

l lin

ks w

ill p

rovi

de c

ultu

ral h

erita

ge,

recr

eatio

nal a

nd t

ouris

m

serv

ices

. If

appr

opria

tely

land

scap

ed a

nd w

ell m

aint

aine

d, s

uch

stru

ctur

es

shou

ld a

lso p

rovi

de a

n ae

sthe

tic e

xper

ienc

e an

d th

e us

ers’

vie

w p

oint

sh

ould

be

cons

ider

ed d

urin

g th

e de

sign

proc

ess.

Eng

inee

rin

g c

onsi

der

atio

ns

Load

and

dra

inag

e ar

e th

e m

ain

engi

neer

ing

aspe

cts

whi

ch w

ill in

fluen

ce

the

desig

n of

the

brid

ge in

term

s of

wha

t veg

etat

ion

it ca

n su

ppor

t and

as

such

shou

ld b

e co

nsid

ered

at t

he in

itial

des

ign

stag

e.

Page 12: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

10

The

build

mat

eria

ls w

ill a

lso a

ffect

the

aes

thet

ics

of t

he b

ridge

and

how

w

ell i

t mer

ges i

nto

the

surr

ound

ing

land

scap

e.

Oth

er k

ey c

onsi

der

atio

ns

Cost

is a

key

fact

or.

Cost

s ca

n be

red

uced

or m

inim

ised

by d

ecre

asin

g th

e lo

ad, s

pan,

and

/or

wid

th o

f th

e st

ruct

ure.

Sho

rter

spa

ns c

an b

e ob

tain

ed

thro

ugh

the

prov

ision

of

inte

rmed

iate

sup

port

s, t

houg

h th

is ca

n in

terf

ere

with

road

saf

ety

and

aest

hetic

con

cern

s. T

he fo

unda

tions

for

the

stru

ctur

e ha

ve a

sig

nific

ant

impa

ct o

n co

st a

nd r

equi

rem

ents

are

rel

ated

to

soil

cond

ition

s and

topo

grap

hy a

t the

site

.

The

brid

ge lo

ad w

ill d

epen

d on

the

tar

get

vege

tatio

n.

Larg

er v

eget

atio

n (t

rees

) will

requ

ire d

eepe

r soi

l to

supp

ort i

ts ro

ot s

truc

ture

whi

ch w

ill h

ave

a hi

gher

load

tha

n sh

allo

wer

roo

ted

vege

tatio

n.

Cons

ider

atio

n co

uld

be

give

n to

con

tain

ing

larg

er v

eget

atio

n (s

uch

as t

rees

and

shr

ubs)

at

dist

inct

lo

catio

ns a

long

the

spa

n ra

ther

tha

n pl

acin

g ov

er t

he e

ntire

are

a. T

he

drai

nage

sys

tem

und

er th

e so

il an

d co

ntro

l of s

oil b

uild

up,

will

also

affe

ct

the

load

and

nee

ds to

be

cons

ider

ed in

des

ign.

Gree

n br

idge

s ca

n be

com

plex

eng

inee

red

stru

ctur

es a

nd t

he a

dvic

e of

an

engi

neer

shou

ld b

e so

ught

.

Page 13: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

11

Ch

oosi

ng

a g

reen

bri

dg

e st

ruct

ure

Fo

ur t

ypes

of

gree

n br

idge

str

uctu

re h

ave

been

dev

elop

ed i

n th

is gu

ide

base

d on

exa

mpl

es o

f gre

en b

ridge

str

uctu

res

from

aro

und

the

wor

ld. (

It is

note

d th

at t

his

guid

e do

es n

ot in

clud

e cu

t an

d co

ver

styl

e br

idge

s w

hich

m

ay b

e ap

prop

riate

to a

ddre

ss la

rge-

scal

e la

ndsc

ape

impa

cts)

. Th

ese

have

be

en te

rmed

as f

ollo

ws:

- N

atur

al B

ridge

-

Wild

life

Brid

ge

- M

ixed

Use

Brid

ge

- M

odifi

ed G

rey

Brid

ge

The

type

of

gree

n br

idge

sel

ecte

d sh

ould

be

base

d on

the

aim

s an

d ob

ject

ives

of

the

proj

ect

(whi

ch i

n tu

rn i

s in

fluen

ced

by l

ands

cape

, bi

odiv

ersit

y an

d ac

cess

nee

ds)

alth

ough

it is

also

not

ed t

hat

the

sele

cted

de

sign

may

be

heav

ily in

fluen

ced

by e

ngin

eerin

g as

pect

s. T

he d

escr

iptio

ns

of e

ach

desig

n ty

pe b

elow

are

inte

nded

as

guid

es.

Whe

n de

signi

ng a

gre

en

brid

ge o

n a

site,

this

will

be

a co

llabo

rativ

e pr

oces

s be

twee

n th

e ro

ad a

nd

brid

ge e

ngin

eers

and

the

env

ironm

enta

l co

nsul

tant

s, w

ith i

nput

fro

m a

w

ide

rang

e of

stak

ehol

ders

. T

he st

ruct

ural

requ

irem

ents

of t

he d

esig

n w

ill

be k

ey in

term

s of w

hat i

s ach

ieva

ble

in e

stab

lishi

ng v

eget

atio

n gr

owth

.

Cost

s Th

e ta

ble

belo

w p

rovi

des e

xam

ples

of g

reen

brid

ges a

nd th

eir c

osts

. W

ithin

th

e gr

een

brid

ge li

tera

ture

rev

iew

, lim

ited

info

rmat

ion

was

foun

d on

cos

ts

and

as s

uch

no d

etai

led

cost

s fo

r ea

ch b

ridge

typ

e id

entif

ied

abov

e ar

e pr

ovid

ed.

Fur

ther

mor

e co

sts

will

be

heav

ily i

nflu

ence

d by

loc

al a

spec

ts

such

as g

eolo

gy a

nd to

pogr

aphy

.

Brid

ge

nam

e,

loca

tion

Cost

2 De

tails

on

stru

ctur

e

Mile

End

, U

K

£5,8

00,0

00

25 m

wid

th o

f la

ndsc

aped

par

klan

d.

Rai

nwat

er r

uns

off th

e br

idge

and

dow

n

into

tan

ks o

n ei

ther

sid

e. I

t is

the

n pu

mpe

d ba

ck o

nto

it an

d re

used

.

Koo

twijk

,

Net

herlan

ds

£2,1

87,6

21

(3 m

illio

n eu

ros)

150m

long

, ho

ur g

lass

sha

pe s

truc

ture

,

80m

wid

e at

its

entr

ance

s an

d 30

m w

ide

in t

he m

iddl

e. 1.

5m w

alls

pla

nted

with

tree

s an

d sh

rubs

Laar

der

Hoo

gt,

Net

herlan

ds

£8,3

85,5

88

(11.

5 m

illio

n eu

ros)

Not

yet

con

stru

cted

. T

wo

brid

ges,

one

70x4

0m a

nd o

ne 4

0x3 0

m

Nat

uurb

urg

Zee

poor

t

£4,0

08,4

93 (

5.5

mill

ion

euro

s)

Sch

edul

ed f

or c

onst

ruct

ion

in 2

016

Zan

derij

Cra

ilio

£10,

569,

588

14.7

5 m

illio

n eu

ros

300m

long

, 50

m w

ide

Asp

ihol

z an

d

Fuch

swie

s,

Sw

itzer

land

5% o

f pr

ojec

t co

st

Con

cret

e of

0.4

m a

nd a

min

imum

soi

l

laye

r of

1.5

m.

Nat

ive

bush

es w

ere

plan

ted

only

at

criti

cal s

pots

and

the

res

t ha

s be

en

left

for

nat

ural

suc

cess

ion.

A55

6,

Che

shire,

UK

Estim

ated

cos

t of

‘gre

enin

g’ t

he a

cces

s

brid

ge £

366,

000,

with

tot

al b

ridg

e co

st

estim

ated

at

£1.1

4m.

Not

yet

con

stru

cted

. P

ropo

sal i

s fo

r an

11m

gre

en b

ridg

e, w

ith a

far

m t

rack

and

a

7 m g

reen

ver

ge.

2 Exc

hang

e ra

te c

alcu

late

d us

ing

ww

w.x

e.co

m o

n 27

/02/

15 r

ate

of 1

GBP

= 1

.372

09 E

UR

Page 14: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

12

Nat

ural

Brid

ge

Thes

e ar

e th

e la

rges

t of

the

fou

r br

idge

typ

es d

efin

ed in

thi

s gu

ide,

with

w

idth

s of

70m

to

100m

or

grea

ter.

By

bein

g of

a la

rger

size

the

aim

is t

o pr

ovid

e an

eco

syst

em le

vel o

f co

nnec

tion.

Th

e la

rger

size

allo

ws

for

the

recr

eatio

n of

hab

itats

and

ide

ally

the

pla

ntin

g sh

ould

be

desig

ned

and

inte

grat

ed s

o th

ere

is ha

bita

t con

tinui

ty fr

om o

ne s

ide

of th

e br

idge

to th

e ot

her.

By

prov

idin

g ha

bita

t co

ntin

uity

thi

s sh

ould

faci

litat

e us

e by

a w

ide

rang

e of

sp

ecie

s.

It

is re

com

men

ded

that

hu

man

us

e is

care

fully

co

nsid

ered

, dep

endi

ng o

n th

e se

nsiti

vity

of t

he ta

rget

wild

life.

W

idth

– 7

0m to

100

m

Soil

– W

here

pos

sible

avo

id i

mpo

rtin

g fr

om o

utsid

e th

e ar

ea.

Aim

for

de

pths

bet

wee

n 1.

5m to

2m

in a

reas

with

tree

pla

ntin

g. S

hallo

wer

dep

ths

may

be

used

in th

e ce

ntre

for g

rass

es a

nd h

erbs

(0.3

m) a

nd s

hrub

s (0

.6m

).

Soil

mus

t be

dee

p en

ough

to

allo

w w

ater

ret

entio

n.

A va

riatio

n in

soi

l de

pths

can

be

used

to c

reat

e a

mos

aic

of v

eget

atio

n, in

clud

ing

mai

ntai

ning

ar

eas o

f bar

e gr

ound

, and

cre

atin

g a

varie

d to

pogr

aphy

.

Habi

tat c

reat

ion

– Ai

m to

cre

ate

habi

tat a

s fo

und

eith

er s

ide

of th

e br

idge

. N

ativ

e sp

ecie

s lo

cal t

o th

e ar

ea s

houl

d be

use

d.

Tree

and

shr

ub p

lant

ing

shou

ld b

e us

ed t

o gu

ide

spec

ies

mov

emen

t ac

ross

the

brid

ge a

nd t

o pr

ovid

e co

ver.

The

pla

ntin

g sh

ould

be

desig

ned

to c

reat

e a

mos

aic

with

tr

ee a

nd s

hrub

pla

ntin

g at

the

end

and

the

mid

dle

sect

ion

left

ope

n w

ith

gras

ses

and

smal

ler v

eget

atio

n. B

rash

, tre

e st

umps

, for

exa

mpl

e, m

ay a

lso

be u

sed

to c

reat

e re

fuge

s fo

r sm

all

anim

als.

If

crea

ting

habi

tat

for

amph

ibia

ns a

ser

ies o

f poo

ls/ w

et d

epre

ssio

ns s

houl

d be

cre

ated

acr

oss t

he

stru

ctur

e, w

ith a

larg

er d

eep

pool

eith

er s

ide.

Bo

ulde

rs (

embe

dded

) may

al

so b

e us

ed e

ither

side

of t

he b

ridge

to p

reve

nt v

ehic

le a

cces

s.

Fenc

ing/

scr

eeni

ng –

Ear

th m

ound

s w

ith h

edge

s pl

ante

d on

top

can

be

used

alo

ng t

he b

ridge

edg

es t

o re

duce

noi

se a

nd l

ight

pol

lutio

n on

the

br

idge

. Th

ese

mou

nds

shou

ld e

xten

d al

ong

the

appr

oach

ram

ps to

tie

into

w

ildlif

e fe

ncin

g. T

he m

ound

plu

s veg

etat

ion

shou

ld a

im to

be

arou

nd 2

m in

he

ight

. Al

tern

ativ

ely

woo

d fe

ncin

g co

uld

be u

sed

as s

cree

ning

; whe

re th

is is

done

then

fenc

ing

shou

ld b

e pl

aced

on

the

oute

r edg

e of

the

brid

ge.

Fig

ure

1:

Exam

ple

ske

tch

of

a N

atu

ral

Bri

dg

e

Page 15: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

13

Wild

life

Brid

ge

Thes

e ar

e ve

ry s

imila

r in

desig

n to

a N

atur

al B

ridge

, but

are

sm

alle

r in

size.

Th

is ty

pe o

f br

idge

is in

tend

ed p

rimar

ily t

o fa

cilit

ate

spec

ies

cros

sing

the

infr

astr

uctu

re.

Des

ign

spec

ifics

may

tar

get

part

icul

ar s

peci

es.

Idea

lly a

n ho

urgl

ass

shap

e sh

ould

be

used

as

this

is be

tter

for

wild

life

loca

ting

the

ram

ps to

cro

ss t

he b

ridge

. It

is re

com

men

ded

that

hum

an u

se is

car

eful

ly

cons

ider

ed, d

epen

ding

on

the

sens

itivi

ty o

f the

targ

et w

ildlif

e.

Wid

th -

40m

-50m

Soil

- Whe

re p

ossib

le a

void

impo

rtin

g fr

om o

utsid

e th

e ar

ea. A

im fo

r dep

ths

betw

een

1.5m

to

2m (m

ay n

eed

to b

e sh

allo

wer

in c

entr

e).

Soil

mus

t be

de

ep e

noug

h to

allo

w w

ater

ret

entio

n.

A va

riatio

n in

soi

l dep

ths

can

be

used

to

crea

te a

mos

aic

of v

eget

atio

n, in

clud

ing

mai

ntai

ning

are

as o

f bar

e gr

ound

, and

cre

atin

g a

varie

d to

pogr

aphy

.

Habi

tat

crea

tion

– Ai

m t

o cr

eate

a h

abita

t m

osai

c, fo

r ex

ampl

e w

ith t

rees

on

eith

er s

ide,

hed

gero

ws

on m

ound

s al

ong

edge

s, th

en i

n th

e m

iddl

e m

eado

w a

nd s

catt

ered

tre

e st

umps

. Th

e ve

geta

tion

shou

ld c

onsid

er t

he

surr

ound

ing

habi

tats

and

loo

k to

ref

lect

the

se.

Any

hed

gero

ws

plan

ted

shou

ld t

ie i

nto

the

tree

s ei

ther

sid

e to

cre

ate

a fli

ght

corr

idor

for

bat

s.

Oth

er a

spec

ts a

s de

taile

d fo

r th

e N

atur

al B

ridge

can

be

cons

ider

ed.

Boul

ders

may

also

be

used

eith

er s

ide

of t

he b

ridge

to

prev

ent

vehi

cle

acce

ss.

Fenc

ing/

scr

eeni

ng –

Ear

th m

ound

s w

ith h

edge

s pl

ante

d on

top

can

be

used

alo

ng t

he b

ridge

edg

es t

o re

duce

noi

se a

nd l

ight

pol

lutio

n on

the

br

idge

. Th

ese

mou

nds

shou

ld e

xten

d al

ong

the

appr

oach

ram

ps to

tie

into

w

ildlif

e fe

ncin

g to

cre

ate

a ba

rrie

r to

ani

mal

s ac

cess

ing

the

road

/rai

lway

. Th

e m

ound

plu

s ve

geta

tion

shou

ld a

im t

o be

aro

und

2m i

n he

ight

. Al

tern

ativ

ely

woo

ded

fenc

ing

coul

d be

use

d as

scre

enin

g.

Fig

ure

2:

Exam

ple

ske

tch

of

a W

ild

life

Bri

dg

e

Furt

her i

nfor

mat

ion

can

be fo

und

in th

e fo

llow

ing

docu

men

ts:

A.Cl

even

ger a

nd M

.Hui

jser

(201

1) W

ildlif

e Cr

ossi

ng S

truc

ture

s Han

dboo

k

(htt

p://

ww

w.c

flhd.

gov/

prog

ram

s/te

chDe

velo

pmen

t/w

ildlif

e/do

cum

ents

/01_

Wild

life_

Cros

sing_

Stru

ctur

es_H

andb

ook.

pdf)

Iuel

l et a

l. (2

003)

Wild

life

and

Traf

fic: A

Eur

opea

n Ha

ndbo

ok fo

r Ide

ntify

ing

Conf

licts

an

d De

signi

ng S

olut

ions

. (h

ttp:

//w

ww

.iene

.info

/wp-

cont

ent/

uplo

ads/

COST

341_

Hand

book

.pdf

)

Page 16: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

14

Mix

ed U

se B

ridge

Th

ese

are

desig

ned

whe

re a

cces

s is t

he p

rinci

ple

aim

and

whe

re a

ny sp

ecie

s us

e is

seen

as

an a

dditi

onal

ben

efit

rath

er t

han

a co

re a

im.

To d

eter

min

e th

e w

idth

, the

min

imum

wid

th o

f th

e na

tura

l zon

e sh

ould

be

calc

ulat

ed,

base

d on

the

pro

ject

aim

s in

ter

ms

of t

arge

t sp

ecie

s.

The

requ

ired

wid

th

for

the

recr

eatio

nal z

one

shou

ld t

hen

be a

dded

to

this

to g

ive

the

tota

l w

idth

. It i

s re

com

men

ded

that

the

recr

eatio

nal z

one

is pl

aced

on

the

oute

r ed

ge t

o m

axim

ise t

he a

rea

of w

ildlif

e zo

ne (

e.g.

so

hum

an d

istur

banc

e is

limite

d to

one

sid

e of

the

wild

life

zone

). A

ltern

ativ

ely

whe

re t

he m

ain

driv

ers

are

acce

ss, w

ith w

ider

bio

dive

rsity

goa

ls, it

may

be

appr

opria

te t

o po

sitio

n th

e re

crea

tiona

l zon

e in

the

cen

tre

of t

he b

ridge

, for

exa

mpl

e as

ha

s bee

n do

ne o

n th

e Sc

otne

y Br

idge

(see

cas

e st

udie

s bel

ow).

Wid

th –

15-

20m

(e.g

. rec

reat

iona

l zon

e: 1

0m, w

ildlif

e zo

ne: 1

5m)

Soil

– W

here

pos

sible

avo

id i

mpo

rtin

g fr

om o

utsid

e th

e ar

ea.

Aim

for

de

pths

bet

wee

n 1.

5m to

2m

(may

nee

d to

be

shal

low

er in

the

cent

re).

Soi

l m

ust

be d

eep

enou

gh t

o al

low

wat

er r

eten

tion.

A v

aria

tion

in s

oil d

epth

s ca

n be

use

d to

cre

ate

a m

osai

c of

veg

etat

ion,

incl

udin

g m

aint

aini

ng a

reas

of

bare

gro

und,

and

cre

atin

g a

varie

d to

pogr

aphy

.

Habi

tat

crea

tion

– As

for

the

oth

er b

ridge

s th

e ai

m is

to

crea

te a

hab

itat

mos

aic.

Shr

ubs

and/

or

a he

dger

ow s

houl

d be

use

d to

cre

ate

a de

gree

of

sepa

ratio

n be

twee

n th

e w

ildlif

e co

rrid

or a

nd t

he p

edes

tria

n zo

ne,

if th

e w

ildlif

e us

ing

the

brid

ge is

like

ly to

be

sens

itive

to d

istur

banc

e.

Fenc

ing/

scr

eeni

ng –

Scr

eeni

ng re

quire

d be

twee

n w

ildlif

e an

d re

crea

tiona

l zo

ne w

ith a

reco

mm

ende

d m

inim

um h

eigh

t of 1

m. I

deal

ly s

cree

ning

sho

uld

be n

atur

al a

nd p

erm

eabl

e to

wild

life,

but

pro

vide

s a v

isual

scre

en.

Boul

ders

m

ay a

lso b

e us

ed e

ither

side

of t

he b

ridge

to p

reve

nt v

ehic

le a

cces

s.

Fig

ure

3:

Exam

ple

ske

tch

of

a M

ixed

Use

Bri

dg

e

Page 17: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

15

Mod

ified

Gre

y Br

idge

A

low

er c

ost

optio

n to

pro

vide

a li

mite

d le

vel o

f m

itiga

tion

is to

ada

pt a

gr

ey b

ridge

(eith

er p

ropo

sed

or e

xist

ing)

. Th

is is

not

an a

ltern

ativ

e to

the

ot

her

gree

n br

idge

opt

ions

as

it is

unlik

ely

to p

rovi

de t

he s

ame

leve

l of

func

tion,

but

it w

ill im

prov

e th

e ge

nera

l per

mea

bilit

y of

the

infr

astr

uctu

re.

This

type

of

optio

n m

ay b

e su

itabl

e fo

r fo

rest

ry a

nd f

arm

tra

cks

acro

ss

infr

astr

uctu

re o

r in

an

urba

n se

ttin

g w

here

it m

ay b

e po

ssib

le t

o m

odify

re

dund

ant

infr

astr

uctu

re,

for

exam

ple

disu

sed

railw

ay a

nd r

oad

brid

ges

whi

ch m

ay b

e us

ed a

s w

ildlif

e co

rrid

ors

or l

inea

r pa

rks.

It

is no

t re

com

men

ded

for t

arm

acke

d ro

ads o

r roa

ds w

ith h

eavy

usa

ge.

A br

idge

can

be

mod

ified

to p

rovi

de a

gre

en st

rip o

n on

e sid

e, o

r eith

er si

de

of t

he r

oad

or t

rack

. T

he m

inim

um w

idth

of

this

strip

is

1m (

alth

ough

id

eally

thi

s sh

ould

be

wid

er t

o m

axim

ise t

he b

enef

its),

with

a s

oil l

ayer

of

0.3m

or g

reat

er.

The

strip

can

be

seed

ed w

ith a

nat

ural

see

d m

ix o

r lef

t to

colo

nise

nat

ural

ly.

Whi

lst th

e st

rip b

ecom

es e

stab

lishe

d, fe

ncin

g be

twee

n th

e st

rip a

nd t

he r

oad

shou

ld b

e co

nsid

ered

to

prev

ent

tram

plin

g an

d co

mpa

ctio

n. D

epen

ding

on

the

wid

th o

f the

str

ip c

onsid

erat

ion

shou

ld b

e gi

ven

to p

rovi

ding

oth

er h

abita

t fe

atur

es s

uch

as d

ead

woo

d, t

ree

stum

ps

and

rock

s, w

hich

may

hav

e va

lue

for i

nver

tebr

ates

and

am

phib

ians

.

This

type

of

brid

ge s

truc

ture

is le

ss li

kely

to

prov

ide

any

land

scap

e va

lue,

bu

t m

ay h

ave

wid

er b

iodi

vers

ity b

enef

its,

such

as

prov

idin

g pl

ants

for

po

llina

ting

spec

ies.

Mod

ifyin

g an

exi

stin

g st

ruct

ure

may

be

mor

e in

kee

ping

w

ith

the

wid

er

land

scap

e su

rrou

ndin

gs

than

pr

ovid

ing

a ne

w

one,

de

pend

ing

on th

e de

sign

of th

e or

igin

al st

ruct

ure.

Fig

ure

4:

Exam

ple

ske

tch

of

a M

odif

ied

Gre

y B

rid

ge

Page 18: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

16

Case

Stu

dies

A21

Scot

ney

Cast

le

Key

fact

s:

Firs

t Gre

en B

ridge

in U

K –

Exam

ple

of a

Mix

ed U

se B

ridge

des

igne

d fo

r hist

oric

land

scap

e pu

rpos

es

Part

of a

Hig

hway

s Age

ncy

impr

ovem

ent s

chem

e fo

r a n

ew d

ual c

arria

gew

ay b

y-pa

ss a

roun

d La

mbe

rhur

st

villa

ge.

The

orig

inal

pro

posa

ls w

ould

hav

e se

vere

d th

e hi

stor

ic W

est D

rive

whi

ch w

as la

id o

ut in

184

2 an

d st

ill

used

as t

he m

ain

entr

ance

to S

cotn

ey C

astle

. Lo

cate

d w

ithin

the

High

Wea

ld A

ON

B.

To m

itiga

te a

“la

ndbr

idge

” w

as b

uilt

whi

ch e

nabl

ed th

e W

est D

rive

to b

e re

inst

ated

on

its o

rigin

al li

ne w

ith

land

scap

e an

d ha

bita

t con

nect

ivity

.

Ther

e ha

ve b

een

wid

er e

colo

gica

l ben

efits

with

evi

denc

e of

dor

mic

e us

ing

the

brid

ge.

It fo

rmed

par

t of t

he £

22 m

illio

n ov

eral

l cos

ts o

f the

sche

me

(inc

ludi

ng P

ublic

Inqu

iry),

but t

he c

ost o

f lan

dbrid

ge

has n

ot b

een

calc

ulat

ed se

para

tely

.

Desi

gn A

spec

ts

Hour

glas

s sha

pe

92m

in le

ngth

(48m

in th

e ce

ntre

and

18m

and

25m

eith

er si

de)

29m

in w

idth

at c

entr

e (5

5m a

t wid

est p

oint

on

east

side

and

43m

on

wes

t sid

e)

Soil

dept

h be

twee

n 0.

6m a

nd 1

.5m

Driv

e ac

ross

brid

ge is

3.5

m w

ide

Plan

ting

to c

reat

e a

cont

inuo

us th

icke

t bet

wee

n 3

and

10m

in w

idth

and

old

tree

stum

ps a

nd b

anks

of m

oss u

sed

to c

reat

e ha

bita

ts

Arra

ngem

ent t

o co

llect

rain

wat

er a

nd to

del

iver

into

soil

laye

rs a

nd a

ribb

ed c

entr

al re

serv

oir

Phot

ogra

phs

Top

phot

o: M

odel

of p

ropo

sed

brid

ge, M

iddl

e ph

oto:

Brid

ge d

urin

g co

nstr

uctio

n ph

ase,

Bott

om p

hoto

: Brid

ge fo

llow

ing

cons

truc

tion

Phot

os c

ourt

esy

of L

UC

Page 19: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

17

A21

Scot

ney

Brid

ge ( P

rovi

ded

cou

rtes

y of

Fir

a La

nd

scap

e)

Page 20: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

2

Banf

f Wild

life

Cros

sings

, Can

ada

Key

fact

s

Exam

ple

of a

Wild

life

Brid

ge

Cons

truc

ted

1996

.

Annu

al m

onito

ring

prov

ides

det

aile

d in

form

atio

n of

brid

ge u

se.

Oth

er c

ross

ings

are

also

pre

sent

(cul

vert

s and

und

erpa

sses

) alo

ng th

e Tr

ans C

anad

ian

High

way

.

The

brid

ges a

re c

lose

d to

the

publ

ic.

Built

to m

itiga

te w

ildlif

e m

orta

lity

and

frag

men

tatio

n

Long

-ter

m m

onito

ring

has f

ound

that

ther

e is

an a

dapt

atio

n pe

riod

and

lear

ning

cur

ve fo

r la

rge

mam

mal

s usin

g th

e w

ildlif

e cr

ossin

g st

ruct

ures

, and

that

ung

ulat

es a

dapt

mor

e qu

ickl

y th

an c

arni

vore

s.

Stud

ies

into

diff

eren

t mon

itorin

g m

etho

ds o

n th

e br

idge

foun

d th

at re

mot

e ca

mer

as a

re th

e m

ost c

ost -

effe

ctiv

e m

eans

of c

ondu

ctin

g cr

ossin

g st

ruct

ure

mon

itorin

g.

The

wild

life

brid

ges a

re p

art o

f a su

ite o

f miti

gatio

n m

easu

res f

or a

n 82

km

sect

ion

of th

e Tr

ans-

Cana

da H

ighw

ay in

Ban

ff N

atio

nal P

ark

whi

ch h

as b

een

upgr

aded

from

two

lane

s to

a fo

ur la

ne d

ivid

ed h

ighw

ay in

198

1. T

he m

itiga

tion

was

inst

alle

d ov

er ti

me

and

was

com

plet

ed

in Ja

nuar

y 20

14. T

here

are

now

38

wild

life

unde

rpas

ses a

nd si

x ov

erpa

sses

.

Desi

gn A

spec

ts

50m

wid

e

Ope

n sp

an b

ridge

stru

ctur

e

Cros

ses f

our l

ane

high

way

Page 21: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

14

Ecod

uct

Wam

bach

, N

ethe

rlan

ds

Key

fact

s

Exam

ple

of a

Nat

ural

Brid

ge.

Cons

truc

ted

2011

-12.

Firs

t gre

en b

ridge

des

igne

d w

ith c

limat

e ch

ange

resil

ienc

e as

an

obje

ctiv

e.

Desig

n co

nsid

ered

clim

ate

chan

ge re

silie

nce

to m

atch

the

wat

er m

anag

emen

t on

the

gree

n br

idge

w

ith In

terg

over

nmen

tal P

anel

on

Clim

ate

Chan

ge b

ased

clim

ate

scen

ario

s of t

he R

oyal

Dut

ch

Met

eoro

logi

cal I

nstit

ute.

Conc

rete

ridg

es a

re g

lued

to th

e de

ck o

f the

gre

en b

ridge

whi

ch fo

rm b

asin

s to

reta

in w

ater

ava

ilabl

e fo

r dro

ught

per

iods

. Pol

ysty

rene

bas

es o

f em

bank

men

ts re

tain

wat

er th

roug

h ra

ised

edge

s cov

ered

w

ith fo

il. T

o av

oid

exce

ss w

ater

dur

ing

rain

fall

peak

s, a

n ov

ersiz

ed d

rain

age

syst

em h

as b

een

desig

ned

to c

hann

el w

ater

to tw

o po

nds.

The

dra

inag

e sy

stem

may

also

be

used

in a

reve

rsed

fa

shio

n, to

supp

lem

ent t

he g

reen

brid

ge w

ith w

ater

.

Desi

gn A

spec

ts

The

adja

cent

pas

ture

land

is to

be

plan

ted

with

woo

ds to

con

nect

into

surr

ound

ing

woo

dlan

d to

cr

eate

a g

reen

cor

ridor

at a

land

scap

e sc

ale.

The

brid

ge is

36m

wid

e an

d 58

m lo

ng.

Phot

ogra

phs

Top

imag

e: D

igita

l des

ign

plan

of b

ridge

, Bot

tom

pho

to: B

ridge

dur

ing

cons

truc

tion

phas

e

Phot

os c

ourt

esy

of V

icto

r Loe

hr, R

ijksw

ater

staa

t

Page 22: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

15

Gro

ene

Wou

d, N

ethe

rlan

ds

Key

fact

s

Exam

ple

of a

Wild

life

Brid

ge

Cons

truc

ted

2003

.

Desig

n ai

med

to c

reat

e op

timal

hum

id c

ondi

tions

for a

mph

ibia

ns.

Loca

ted

with

in th

e N

atio

nal L

ands

cape

Gro

ene

Wou

ld, t

he b

ridge

con

nect

s wet

land

are

as

whi

ch a

re b

isect

ed b

y a

mot

orw

ay.

The

brid

ge is

clo

sed

to th

e pu

blic

.

Desi

gn A

spec

ts

50m

wid

e an

d 65

m lo

ng, c

ross

es th

e m

otor

way

at 7

m a

bove

gro

und

leve

l.

The

acce

ss ra

mps

lead

ing

in a

re 1

10m

and

85m

and

at a

gra

dien

t rat

io o

f 1:1

4 an

d 1:

10

resp

ectiv

ely.

0.5m

of t

opso

il on

the

brid

ge a

nd 1

m o

n th

e ac

cess

ram

ps.

The

tops

oil h

as b

een

take

n fr

om th

e ar

ea im

med

iate

ly su

rrou

ndin

g th

e br

idge

, and

is p

lace

d in

its o

rigin

al se

quen

ce to

mai

ntai

n la

yers

.

Cont

rolla

ble

grou

ndw

ater

leve

l on

the

top

of th

e br

idge

, acr

oss t

he le

ngth

of t

he st

ruct

ure

and

the

acce

ss ra

mps

, with

a w

etla

nd zo

ne c

reat

ed b

y a

chai

n of

smal

l pon

ds.

Wat

er is

pu

mpe

d up

to th

e to

p of

the

brid

ge a

nd sl

owly

rele

ased

thro

ugh

the

casc

ade

of sm

all p

ools

tow

ards

big

ger p

ools

at th

e bo

ttom

on

the

acce

ss ra

mp.

Six

amph

ibia

n sp

ecie

s rec

orde

d on

the

brid

ge, c

omm

on to

ad, c

omm

on fr

og, s

moo

th n

ewt,

grea

t cre

ated

new

t, m

arsh

frog

and

edi

ble

frog

.

Phot

ogra

phs

Top

phot

ogra

ph: S

ide

on v

iew

of b

ridge

(Pro

vide

d co

urte

sy o

f ALT

ERRA

/ E.

A. v

an d

er G

rift)

Bott

om p

hoto

grap

h: V

iew

on

top

of b

ridge

(Pro

vide

d co

urte

sy o

f ALT

ERRA

/ E.

A. v

an d

er

Grift

)

Page 23: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

15

Aeria

l vie

w o

f Gro

ene

Wou

d (P

rovi

ded

cour

tesy

of R

ijksw

ater

staa

t)

Page 24: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

16

Post

-con

stru

ctio

n re

com

men

datio

ns

Mon

itor

ing

A m

onito

ring

plan

sho

uld

be d

evel

oped

whi

ch w

ill h

elp

to a

sses

s th

e ef

fect

iven

ess

of t

he g

reen

brid

ge.

The

nat

ure

of t

he p

lan

will

be

dete

rmin

ed fr

om th

e or

igin

al a

ims

of th

e gr

een

brid

ge a

nd th

e m

onito

ring

shou

ld lo

ok t

o es

tabl

ish if

the

aim

s ha

ve b

een

met

. Th

e le

vel o

f su

rvey

un

dert

aken

will

be

depe

nden

t on

thos

e ai

ms.

For e

xam

ple

for a

brid

ge w

hich

has

bee

n de

velo

ped

for s

peci

es u

se, i

t may

be

app

ropr

iate

to in

stal

l cam

era

trap

s on

the

brid

ge a

s the

se h

ave

foun

d to

be

a s

ucce

ssfu

l m

etho

d of

mon

itorin

g gr

een

brid

ges.

W

here

hab

itat

crea

tion

has

been

un

dert

aken

, th

en

bota

nica

l su

rvey

s sh

ould

be

un

dert

aken

.

Spec

ific

mon

itorin

g ap

proa

ches

may

be

need

ed f

or s

ome

spec

ies

such

as

bats

. M

onito

ring

shou

ld f

ollo

w s

peci

es-s

peci

fic e

stab

lishe

d pr

otoc

ols

whe

re t

hese

are

ava

ilabl

e.

The

met

hodo

logy

for

pre

, du

ring

and

post

co

nstr

uctio

n su

rvey

sho

uld

be c

onsis

tent

to a

llow

dat

a to

be

com

pare

d an

d us

ed to

ass

ess t

he e

ffect

iven

ess o

f the

stru

ctur

e.

It is

impo

rtan

t tha

t lon

g te

rm m

onito

ring

is un

dert

aken

as

spec

ies

use

may

in

crea

se fo

llow

ing

a pe

riod

of fa

mili

arisa

tion.

W

ith t

his

in m

ind,

a t

ypic

al

mon

itorin

g pr

ogra

mm

e m

ay s

urve

y th

e br

idge

ann

ually

for y

ears

1-3

, the

n ye

ar 5

and

yea

r 10

follo

win

g co

nstr

uctio

n.

Any

misu

se o

f the

brid

ge id

entif

ied

durin

g m

onito

ring

shou

ld b

e re

port

ed

and

if re

quire

d re

com

men

datio

ns fe

d in

to th

e m

aint

enan

ce p

lan

or u

sed

to

amen

d th

e de

sign

to a

llow

the

stru

ctur

e to

del

iver

its o

rigin

al o

bjec

tives

.

The

findi

ngs

of t

his

mon

itorin

g sh

ould

be

revi

ewed

in r

elat

ion

to p

roje

ct

aim

s an

d sh

ould

be

repo

rted

to

Nat

ural

Eng

land

to

help

with

fur

ther

pl

anni

ng a

nd d

esig

n of

gre

en b

ridge

s.

Man

agem

ent

and

Mai

nte

nan

ce

A de

taile

d m

anag

emen

t an

d m

aint

enan

ce p

lan

shou

ld b

e de

velo

ped;

thi

s sh

ould

tie

into

the

mon

itorin

g, m

akin

g ch

ange

s w

here

nec

essa

ry if

issu

es

are

pick

ed

up

durin

g th

e m

onito

ring.

The

plan

sh

ould

de

tail

the

man

agem

ent

for

the

first

thr

ee y

ears

aft

er c

onst

ruct

ion.

A

fter

tha

t th

e m

anag

emen

t sh

ould

be

adap

ted

base

d on

the

fin

ding

s of

mon

itorin

g an

d sh

ould

be

inco

rpor

ated

into

the

man

agin

g ag

ency

’s lo

ng te

rm m

aint

enan

ce

prog

ram

me.

The

resp

onsib

ility

for

ong

oing

mai

nten

ance

sho

uld

be a

gree

d fr

om t

he

proj

ect o

utse

t. T

his

is es

peci

ally

impo

rtan

t whe

n th

e or

gani

satio

n ha

s no

t be

en in

volv

ed in

the

plan

ning

pro

cess

. It

is im

port

ant t

hat t

hey

are

awar

e of

the

pur

pose

of

the

brid

ge a

long

with

the

mai

nten

ance

pla

n an

d as

soci

ated

mai

nten

ance

cos

ts.

Com

mun

ity e

ngag

emen

t in

the

des

ign

of

the

brid

ge c

an le

ad t

o a

Frie

nds

Grou

p be

ing

form

ed w

hich

can

hel

p to

m

aint

ain

the

gree

n br

idge

as a

hig

h qu

ality

gre

ensp

ace.

Mai

nten

ance

sho

uld

incl

ude

insp

ectio

n of

the

brid

ge d

rain

age

to e

nsur

e it

rem

ains

func

tiona

l.

The

man

agem

ent

of t

he b

ridge

sho

uld

be t

ailo

red

to t

he h

abita

ts c

reat

ed

on th

e st

ruct

ure.

For

exa

mpl

e it

may

be

appr

opria

te fo

r an

annu

al h

ay c

ut

whe

re m

eado

ws

have

bee

n so

wn,

with

scr

ub a

nd h

edge

row

man

agem

ent

ever

y 3-

5 ye

ars

and

tree

cop

pici

ng e

very

5-1

0 ye

ars

depe

ndin

g on

the

sp

ecie

s use

d.

Page 25: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

17

Refe

renc

es

Aher

n et

al.

(200

9). I

ssue

s an

d M

etho

ds f

or T

rans

disc

iplin

ary

Plan

ning

of

Com

bine

d W

ildlif

e an

d Pe

dest

rian

High

way

Cro

ssin

gs.

TRB

2009

Ann

ual

Mee

ting.

(h

ttp:

//w

ww

.itre

.ncs

u.ed

u/AD

C30/

09_T

RB_W

inte

r_Co

nfer

ence

/Pre

sent

ati

ons/

Aher

n_et

al_T

RB_W

ALDE

N_p

aper

.pdf

) Ba

nk, F

. G.,

Irwin

, C. L

., Ev

ink,

G. L

., Gr

ay, M

. E.,

Hago

od, S

., Ki

nar.

J, R.

, Lev

y.

A., P

aulso

n, D

., Re

dige

r, B.

, Sau

vajo

t, R.

M.,

Scot

t, D.

J.,

Whi

te, P

. (20

02).

Wild

life

Habi

tat

Conn

ectiv

ity

Acro

ss

Euro

pean

Hi

ghw

ays.

(h

ttp:

//w

ww

.peo

ples

way

wild

lifec

ross

ings

.org

/imag

es/c

ross

ings

truc

ture

s/d

ocum

ents

/wild

life_

habi

tat_

conn

ectiv

ity_a

cros

s_eu

rope

an_h

ighw

ays.

pdf).

Clev

enge

r, A.

P.,

Ford

, A.

T.,

Saw

aya,

M.A

. (2

009)

. Ba

nff

Wild

life

Cros

sings

Pr

ojec

t: In

tegr

atin

g Sc

ienc

e an

d Ed

ucat

ion

in

Rest

orin

g Po

pula

tion

Conn

ectiv

ity A

cros

s Tr

ansp

orta

tion

Corr

idor

s. P

repa

red

for

Park

s Ca

nada

Ag

ency

. Cl

even

ger,

A.P.

an

d Fo

rd,

A.T.

(2

010)

. Ch

apte

r 2.

W

ildlif

e Cr

ossin

g St

ruct

ures

, Fe

ncin

g,

and

Oth

er

High

way

De

sign

Cons

ider

atio

ns.

In:

Beck

man

n, J

.P e

t al

. W

ildlif

e Cr

ossin

g St

ruct

ures

- C

urre

nt P

ract

ices

. W

ashi

ngto

n: Is

land

Pre

ss. 1

7-49

. De

part

men

t fo

r Co

mm

uniti

es

and

Loca

l Go

vern

men

t (2

012)

N

atio

nal

Plan

ning

Po

licy

Fram

ewor

k (h

ttps

://w

ww

.gov

.uk/

gove

rnm

ent/

uplo

ads/

syst

em/u

ploa

ds/a

ttac

hmen

t_d

ata/

file/

6077

/211

6950

.pdf

)

Depa

rtm

ent

for

Tran

spor

t (2

014)

N

atio

nal

Net

wor

ks

Nat

iona

l Po

licy

Sta

tem

ent

(htt

ps:/

/ww

w.g

ov.u

k/go

vern

men

t/up

load

s/sy

stem

/upl

oads

/att

achm

ent_

dat

a/fil

e/38

7222

/nps

nn-p

rint.p

df)

DEFR

A (2

011)

Nat

ural

Env

ironm

ent

Whi

te P

aper

: Th

e N

atur

al C

hoic

e:

Secu

ring

the

Valu

e of

N

atur

e (h

ttps

://w

ww

.gov

.uk/

gove

rnm

ent/

uplo

ads/

syst

em/u

ploa

ds/a

ttac

hmen

t_d

ata/

file/

2288

42/8

082.

pdf)

Law

ton,

J.H

., Br

othe

rton

, P.

N.M

., Br

own,

V.K

., El

phic

k, C

., Fi

tter

, A.

H.,

Fors

haw

, J.,

Ha

ddow

, R.

W.,

Hilb

orne

, S.

, Le

afe,

R.

N.,

Mac

e,

G.M

., So

uthg

ate,

M.P

., Su

ther

land

, W

.A.,

Tew

, T.

E.,

Varle

y, J

., &

Wyn

ne,

G.R.

(2

010)

Mak

ing

Spac

e fo

r N

atur

e: a

rev

iew

of

Engl

and’

s w

ildlif

e sit

es a

nd

ecol

ogic

al

netw

ork.

Re

port

to

De

fra.

(h

ttp:

//ar

chiv

e.de

fra.

gov.

uk/e

nviro

nmen

t/bi

odiv

ersit

y/do

cum

ents

/201

009

spac

e-fo

r-na

ture

.pdf

)

Euro

Nat

ur (

2010

). TE

WN

Man

ual.

Reco

mm

enda

tions

for

the

red

uctio

n of

ha

bita

t fr

agm

enta

tion

caus

ed b

y tr

ansp

ort

infr

astr

uctu

re d

evel

opm

ent.

Euro

Nat

ur F

ound

atio

n, R

adol

fzel

l Iu

ell,

B., B

ekke

r, G.

J., C

uper

us, R

., Du

fek,

J.,

Fry,

G.,

Hick

s, C

., Hl

aváˇ

c, V

., Ke

ller,

V.,

B.,

Rose

ll, C

., Sa

ngw

ine,

T.,

Tørs

løv,

N.,

Wan

dall,

B.

le M

aire

, (E

ds.)

(200

3) W

ildlif

e an

d Tr

affic

: A

Euro

pean

Han

dboo

k fo

r Id

entif

ying

Co

nflic

ts

and

Desig

ning

So

lutio

ns.

(htt

p://

ww

w.ie

ne.in

fo/w

p-co

nten

t/up

load

s/CO

ST34

1_Ha

ndbo

ok.p

df)

Rued

iger

, B.

, Di

Gior

gio,

M.

(200

7).

Safe

Pas

sage

- A

Use

r's G

uide

To

Deve

lopi

ng E

ffect

ive

High

way

Cro

ssin

gs F

or C

arni

vore

s An

d O

ther

Wild

life.

(h

ttp:

//w

ww

.wild

lifec

onsu

lting

reso

urce

s.co

m/p

df/C

ar)

U.S

Dep

artm

ent o

f Tra

nspo

rtat

ion.

Fed

eral

Hig

hway

Adm

inist

ratio

n. (2

011)

. W

ildlif

e Cr

ossin

g St

ruct

ure

Hand

book

- D

esig

n an

d Ev

alua

tion

in N

orth

Am

eric

a.

Publ

icat

ion

No.

FH

WA-

CFL/

TD-1

1-00

3 (h

ttp:

//w

ww

.cflh

d.go

v/pr

ogra

ms/

tech

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lopm

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life/

docu

men

ts/0

1_W

ildlif

e_Cr

ossin

g_St

ruct

ures

_Han

dboo

k.pd

f )

Van

der G

rift,

E, O

ttbu

rg, F

and

Sne

p, R

(201

0) M

onito

ring

wild

life

over

pass

us

e by

am

phib

ians

: do

art

ifici

ally

mai

ntai

n hu

mid

con

ditio

ns e

nhan

ce

cros

sing

rate

s (In

: Ad

aptin

g to

cha

nge.

- R

alei

gh,

Nor

th C

arol

ina,

USA

:

Page 26: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

18

ICO

ET, 2

010

- p.

341

– 3

47) (

http

://w

ww

.wag

enin

genu

r.nl/e

n/Pu

blic

atio

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tails

.htm

?pub

licat

ionI

d=pu

blic

atio

n-w

ay-3

4313

2333

333

)

Van

der

Grift

, E. A

., O

ttbu

rg, F

., Po

uwel

a, R

., Di

rkse

n, J

. (20

11).

Mul

tiuse

O

verp

asse

s: D

oes

hum

an U

se Im

pact

The

Use

By

Wild

life.

Pro

ceed

ings

of

the

2011

Inte

rnat

iona

l Con

fere

nce

of E

colo

gy a

nd T

rans

port

atio

n. S

essio

n CN

T-5,

N

ew

Cons

ider

atio

ns

for

Habi

tat

Conn

ectiv

ity

(ICO

ET

2011

Pr

ocee

ding

s).

Van

der G

rift,

E., D

irkse

n, J.

, Ott

burg

, F.,

Pouw

els,

R. (

2011

). Re

crea

tive

use

of e

codu

cts:

is th

at p

ossib

le?

Vakb

lad

Nat

uur B

os L

ansc

hap.

Vol

:8, I

ss:6

, 12-

15.

Deta

ils o

n M

ile E

nd G

reen

Brid

ge:

htt

p://

ww

w.c

zwg.

com

/wor

ks/g

reen

-br

idge

Deta

ils o

n Ko

otw

ijk G

reen

Brid

ge:

http

://w

ww

.iees

.ch/

cs/c

s_3.

htm

l

Deta

ils o

n La

arde

r Ho

ogt

Gree

n Br

idge

and

Nat

uurb

urg

Zeep

oort

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en

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ge: h

ttp:

//nl

.wik

iped

ia.o

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iki/E

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Page 27: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

19

Page 28: Natural England Green Bridges Guide · 2019. 1. 16. · structures include wildlife overpasses and green bridg es, bridges, culverts, and pipes. ... der ecosystem services, ... bridges

20

Orig

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onsu

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s for

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land

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a G

uida

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LI T

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s Inn

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Dec

201

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