Soil

Ind

icat

ors

of Q

uee

nsla

nd W

etla

nds Brown Lake

North Stradbroke Island

Study AreaBrown Lake is located approximately 4 km east of Dunwich on North Stradbroke Island, South-East Queensland.

Brown lake is a perched lake which form when an impermeable layer of sand become cemented. This cemented layer,known as coffee rock prevents rainwater from percolating through to the regional aquifer1.

This is an example of a coastal and sub-coastal non-floodplain sand lake (perched) in the South-East Queensland Bioregion.

Climate2

0

100

200

300

400

500

600

700

800

900

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov DecMonth

Rai

nfal

l-Eva

pora

tion

(mm

)

0

5

10

15

20

25

30

35

40

Tem

pera

ture

(Deg

.C)

Rain Evap

Temp (min) Temp (max)

The study area is situated within a subtropical climatic region with a wet and dry season. Rainfall exceeds evaporation in the majority of months. The average annual rainfall for the area is 1668 mm.

Landform and Inundation

Perched Lake

Permanent freshwater inundation from overland flow

Soils3 Podsdols and Organosols

Vegetation4 Swamps with Baumea spp., Juncus spp. and Lepironia articulata (RE 12.2.1�)12.2.1�)

Geology� Pleistocene beach ridge systems (quartz sand)

Disturbance Little to no disturbance

Soil

In

dic

ator

s of

Q

ue

ensl

and

W

etla

nd

s Location GDA94 • MGA Coordinates : �42618 E, 69�8�99 N, Zone �6 • Lat/Long : -27.49��7 S, 1�3.4314� E

Landscape Diagram

Brown Lake Site 117

Site 118Site 119

Site 120

Transition zone

Outer zone

Very shallow water table

1.2 m

140 m

Soil Profiles Site 117Site 118

0.2 m

P1

0.3� m

0.� m

P21

P22

A11

A12

A21e

0.2 m

0.4� m

1.0 m

Fibric loam textures, very high organic carbon content, dark colours and shallow water

table all indicate a permanently waterlogged environment

Sites 119 and 120 (not shown) similar to this profile

Low chroma values in the surface 0.3 m is the only wetland soil indicator observed

For soils dominated by sand textures, low chroma values alone are not considered good indicators of

wetland soils without additional indicators

such as organic materials, redox

features (like mottles) or ferruginous root channels and pore

linings6

Soil

In

dic

ator

s of

Q

ue

ensl

and

W

etla

nd

s Soil Indicators Present (within 0.3 m of surface)

Indicator7 Site 117 Site 118Organic materials and organic carbon (OC)*

No organic materials OC: 1.04%

Organic materials to 0.3 m OC: 34.6%

Matrix colour Greyish brown to dark grey Dark brown to black

Chroma (thickness of layer)**

Present (0.3 m) Present (0.3 m)

Mottles and Segregations

Not present Not present

Depth to groundwater Not present 0.1 m

Ferruginous root channel and pore linings

Not present Not present

pH*8 Very strongly acid Very strongly acid

Texture Sand Loam

Acid sulfate material Not present Not present

Electrical Conductivity (EC)8

Non saline Non saline

Indicator7 Site 119 Site 120 Organic materials and organic carbon*

Organic materials to 0.3 m OC: 2�%

Organic materials to 0.3 m OC: 36.3%

Matrix colour Black Black

Chroma (thickness of layer)**

Present (0.3 m) Present (0.3 m)

Mottles and Segregations

Not present Not present

Depth to groundwater 0.01 m 0.01 m

Ferruginous root channel and pore linings

Not present Not present

pH*8 Very strongly acid Very strongly acid

Texture Loam Loam

Acid sulfate material Not present Not present

Electrical Conductivity (EC)8

Non saline Non saline

*Organic carbon % (Dumas method) and pH taken from surface (0-0.1 m) **Chroma value is less than or equal to 2

Summary of Field Observations• The presence of swamp hummock microrelief is typical of a saturated environment

• Fibric and sapric materials indicative of a waterlogged environment (Figure 1)

• High water table with poor external drainage suggests a permanently inundated area

• No evidence of sulfidic materials

• Organic acids produced from organic materials create a very acidic environment (pH range from 3.� in the saturated zone to 4.� in the outer zone)

Figure 1: Fibrous mat of roots which sit on a shallow water table

Soil Indicators of Queensland WetlandsSo

il M

orph

olog

y

Site

117

Clas

sifi

cati

on

Aust

ralia

n So

il Cl

assi

fica

tion

Aq

uic

Podo

sol

Land

form

Ele

men

t D

unes

lope

Mor

phol

ogic

al T

ype

Low

er s

lope

Hor

izon

Dep

th (

m)

Boun

dary

Text

ure

Colo

urM

ottl

esCo

arse

Fr

agm

ents

Stru

ctur

eSe

greg

atio

nsCo

nsis

tenc

e

A11

0 to

.2

gra

dual

to

sand

very

dar

k gr

eyis

h br

own

(10Y

R32)

no

neno

nesi

ngle

gra

inno

neve

ry w

eak

dry

A12

.2 t

o .4

� c

lear

to

sand

dark

gre

y (1

0YR4

1)

none

none

sing

le g

rain

none

very

wea

k m

oder

atel

y m

oist

A21

e.4

� to

1 d

iffu

se t

osa

ndlig

ht b

row

nish

gre

y (1

0YR6

2)no

neno

nesi

ngle

gra

inno

neve

ry w

eak

mod

erat

ely

moi

st

A22

e1

to 1

.2 d

iffu

se t

osa

ndlig

ht b

row

nish

gre

y (1

0YR6

2)no

neno

nesi

ngle

gra

inno

neve

ry w

eak

moi

st

A23

e1.

2 to

1.3

�-

sand

light

gre

y (1

0YR7

2)

few

(2-

10%)

fine

(<

� m

m)

fain

t br

own

mot

tles

none

sing

le g

rain

none

very

wea

k w

et

Site

118

Clas

sifi

cati

on

Aust

ralia

n So

il Cl

assi

fica

tion

Re

golit

hic,

Aci

dic,

Sap

ric

Org

anos

olLa

ndfo

rm E

lem

ent

Swam

p M

orph

olog

ical

Typ

e Si

mpl

e sl

ope

Hor

izon

Dep

th (

m)

Boun

dary

Text

ure

Colo

urM

ottl

esCo

arse

Fr

agm

ents

Stru

ctur

eSe

greg

atio

nsCo

nsis

tenc

e

P10

to .

2 g

radu

al t

ofib

ric

loam

very

dar

k br

own

(10Y

R22

)no

neno

ne-

none

wea

k w

et

P21

.2 t

o .3

� g

radu

al t

osa

pric

loam

blac

k (1

0YR

21)

none

none

-no

new

eak

wet

P22

.3�

to .

�-

sapr

ic lo

ambl

ack

(10Y

R21

)no

neno

ne-

none

wea

k w

et

Site

119

Clas

sifi

cati

on

Aust

ralia

n So

il Cl

assi

fica

tion

Rego

lithi

c, A

cidi

c, H

emic

Org

anos

olLa

ndfo

rm E

lem

ent

Swam

pM

orph

olog

ical

Typ

e Fl

at

Hor

izon

Dep

th (

m)

Boun

dary

Text

ure

Colo

urM

ottl

esCo

arse

Fr

agm

ents

Stru

ctur

eSe

greg

atio

nsCo

nsis

tenc

e

P11

0 to

.1 g

radu

al t

ofib

ric

loam

blac

k (1

0YR

21)

none

none

-no

neve

ry w

eak

wet

P12

.1 t

o .3

-fib

ric

loam

blac

k (1

0YR

21)

none

none

-no

neve

ry w

eak

wet

Soil Indicators of Queensland WetlandsSi

te 1

20Cl

assi

fica

tion

Au

stra

lian

Soil

Clas

sifi

cati

on

Rego

lithi

c, A

cidi

c, H

emic

Org

anos

olLa

ndfo

rm E

lem

ent

Swam

pM

orph

olog

ical

Typ

e Fl

at

Hor

izon

Dep

th (

m)

Boun

dary

Text

ure

Colo

urM

ottl

esCo

arse

Fr

agm

ents

Stru

ctur

eSe

greg

atio

nsCo

nsis

tenc

e

P11

0 to

.1-

fibri

c lo

ambl

ack

(10Y

R21

) no

neno

ne-

none

very

wea

k w

et

P12

.1 t

o .2

-fib

ric

loam

blac

k (1

0YR

21)

none

none

-no

neve

ry w

eak

wet

Soil

Chem

istr

y

Site

Dep

th (

m)

pH*

EC (

dS/m

)Cl

(m

g/kg

)N

O3-

N (

mg/

kg)

TC%

**TN

%**

117

0.00

-0.1

04.

80.

01<2

0<1

1.04

<0.0

3

0.20

-0.3

04.

60.

0122

<10.

6�<0

.03

0.40

-0.�

04.

90.

01<2

0<1

0.12

<0.0

3

118

0.00

-0.1

03.

60.

7�2

6<1

34.6

1.04

0.20

-0.3

03.

40.

4730

91

3�1.

47

0.40

-0.�

03.

40.

3622

3<1

32.2

1.29

119

0.00

-0.1

03.

60.

221�

0<1

2�0.

93

0.20

-0.3

03.

70.

2620

81

26.7

1.23

120

0.00

-0.1

03.

60.

�239

82

36.3

1.29

0.10

-0.2

03.

60.

282�

4�

31.4

1.36

*Aqu

eous

1:�

**To

tal c

arbo

n an

d to

tal n

itro

gen

Refe

renc

es1.

QW

P (2

008)

. W

etla

nd H

abit

at T

ypol

ogy

– Pa

lust

rine

and

Lac

ustr

ine

Wet

land

s, U

npub

lishe

d.

2. Q

ueen

slan

d D

epar

tmen

t of

Nat

ural

Res

ourc

es a

nd W

ater

(20

08).

SIL

O [

onlin

e].

Avai

labl

e at

htt

p://

ww

w.l

ongp

addo

ck.q

ld.g

ov.a

u/si

lo/

[acc

esse

d 5/

11/2

007]

.

3. I

sbel

l RF

(20

02).

The

Aus

tral

ian

Soil

Clas

sifi

cati

on.

CSIR

O P

ublis

hing

, Co

lling

woo

d, V

icto

ria,

rev

ised

edi

tion

.

4. E

PA (

2008

) Re

gion

al E

cosy

stem

s. [

onlin

e].

Avai

labl

e at

htt

p://

ww

w.e

pa.q

ld.g

ov.a

u/na

ture

_con

serv

atio

n/bi

odiv

ersi

ty/r

egio

nal_

ecos

yste

ms/

[ac

cess

ed 2

8/06

/08]

.

5. B

urea

u of

Min

eral

Res

ourc

es (1

978)

. M

oret

on:

Aus

tral

ia 1

:250

,000

Geo

logi

cal

Seri

es,

Bure

au o

f M

iner

al R

esou

rces

, Ca

nber

ra.

6. R

icha

rdso

n JL

and

Vep

rask

as M

J (2

001)

. W

etla

nd S

oils

: G

enes

is,

Hyd

rolo

gy,

Land

scap

es a

nd C

lass

ifica

tion

. CR

C Pr

ess,

Flo

rida

.

7. B

ryan

t KB

, W

ilson

PR,

Big

gs A

JW,

Brou

gh D

M a

nd B

urge

ss J

W (

2008

). S

oil

Indi

cato

rs o

f Q

ueen

slan

d W

etla

nds:

Sta

te-w

ide

asse

ssm

ent

and

met

hodo

logy

. Q

ueen

slan

d D

epar

tmen

t of

Nat

ural

Res

ourc

es a

nd W

ater

. Br

isba

ne.

8. H

azel

ton

P an

d M

urph

y B

(200

7).

Inte

rpre

ting

Soi

l Te

st R

esul

ts:

Wha

t do

all

the

num

bers

mea

n?.

[2nd

ed]

. CS

IRO

pub

lishi

ng.

Colli

ngw

ood

Vict

oria

. 93

11

66

21

80

64

3