Channel Country landforms and the processes that shape themp p

Dr Jerry MaroulisDr Jerry MaroulisFaculty of Education/Australian Centre for Sustainable Catchments (ACSC)Faculty of Education/Australian Centre for Sustainable Catchments (ACSC)University of Southern QueenslandUniversity of Southern Queensland (Photo courtesy: The Courier Mail)(Photo courtesy: The Courier Mail)

Seminar PlanSeminar PlanAcknowledgementsAcknowledgementsWho Who am I?am I?GeomorphologicalGeomorphological research tour of Cooper research tour of Cooper

CreekCreekCreekCreek5 DERM 5 DERM ‘Questions of Interest’‘Questions of Interest’::

Riparian ecosystem functionRiparian ecosystem function Riparian ecosystem functionRiparian ecosystem function Natural rates of erosionNatural rates of erosion Sediment traps Sediment traps –– riparian or floodplain?riparian or floodplain?pp p pp p Possible impacts of change of flow on geomorphologyPossible impacts of change of flow on geomorphology Geomorphic consideration relevant to WRP and WRGeomorphic consideration relevant to WRP and WR

C l iC l iConclusionConclusion

Acknowledgementsg

University of WollongongUniversity of WollongongNanson, Jones, Cendon, Larsen, Rickleman, etc

University of Southern Q l d (USQ)Queensland (USQ)ACSC

GeoImage & DigitalGlobeN W ld Vi 2New World View-2satellite data

Who am I?• Fluvial geomorphologist/Quaternary scientist

Deputy Director ACSC• Deputy Director, ACSC & Senior Lecturer, Faculty of Education, USQ

• PhD (Cooper Creek development over past 750,000 years)• 20+ years researching Cooper Creek, central Australia

Photo courtesy Photo courtesy -- Courier MailCourier Mail

Geomorphology Geomorphology Geomorphology Geomorphology

The study of landforms The study of landforms yyand landscapesand landscapes•• Including description, Including description,

classification origin classification origin classification, origin, classification, origin, development, and history of development, and history of planetary surfaces. planetary surfaces.

Seeks to identify Seeks to identify Seeks to identify Seeks to identify regularities regularities among among landforms and landforms and processesprocessesthat lead to that lead to patternspatterns. . (Predictability)(Predictability)

River Platte, USA: NASA/Goddard Space Flight Center- Image shows flood waters as they recede (Oct 4, 1993)

http://www.ebsinstitute.com/EBS.EOS.FL.html

Study Study AreaArea

Cooper Creek Cooper Creek F tF tFeaturesFeatures

•• Study area:Study area: Mt Mt HowittHowitt to to TooleyTooleyWooleyWooley WaterholesWaterholes

~180km length~180km length•• Floodplain gradient:Floodplain gradient: ~10cm/km~10cm/kmFloodplain gradient:Floodplain gradient: 10cm/km10cm/km•• Floodplain width:Floodplain width: rapidly rapidly d/sd/s

~80km (Mt ~80km (Mt HowittHowitt))100m (100m (NappaNappa MerrieMerrie))~100m (~100m (NappaNappa MerrieMerrie))

•• HydrologyHydrology: : Q Q d/sd/s (internal (internal drainage)drainage)•• Geology:Geology: structural controlsstructural controls•• Geomorphology:Geomorphology: mudmud--dominated floodplaindominated floodplainmudmud dominated floodplaindominated floodplain sporadic sand dunessporadic sand dunes assortment of channelsassortment of channels

Floodplain CharacteristicsFloodplain Characteristics

Approx. cross valley slope

Cooper Creek ImagesCooper Creek Images

Sedimentary characteristics of Sedimentary characteristics of the Cooper Creek floodplainthe Cooper Creek floodplain

Group 1: Group 2:Group 1: Mud-Sand

floodplain units

Group 2:Aeolian-Fluvial

interactionsfloodplain units interactions

Group 1: Floodplain facies Group 1: Floodplain facies Extensive sandExtensive sand--dominated dominated faciesfacies ((KatipiriKatipiri

Formation)Formation)Formation)Formation)Fluvial sands overlain by fluvial Fluvial sands overlain by fluvial mudsmuds

~ 2~ 2--7m mud overlying 36m+ of fluvial sand7m mud overlying 36m+ of fluvial sand 2 2 7m mud overlying 36m+ of fluvial sand7m mud overlying 36m+ of fluvial sandOldest sand date: >700,000 years @ 27mOldest sand date: >700,000 years @ 27m

Fluvial sands most dominant floodplain unitFluvial sands most dominant floodplain unitFluvial sands most dominant floodplain unitFluvial sands most dominant floodplain unitVery little clay below nearVery little clay below near--surface mud cappingsurface mud cappingSandSand--dominated laterally active meandering systemdominated laterally active meandering systemSandSand dominated laterally active meandering systemdominated laterally active meandering system

Western tributary systems invaded by verticallyWestern tributary systems invaded by vertically--accreting mud units from Cooperaccreting mud units from Cooper (shown later)(shown later)accreting mud units from Cooper accreting mud units from Cooper (shown later)(shown later)

Basal Sands, Cooper CreekBasal Sands, Cooper Creek

Floodplain Transect Floodplain Transect -- Shire RdShire Rd

RL0

3

RL Mud unit

6

9

12

80ka12

15

18

Sand units

24

21

30

27

Reticulate Reticulate ChannelsChannelsChannelsChannelsSelf mulching clay soils:When dry

When wete e

High High i ii isinuousity sinuousity surficialsurficialsurficial surficial

channelschannels

Billabongs (Waterholes)Billabongs (Waterholes)

Often located within channel Often located within channel segments where segments where flow flow

Often located within channel Often located within channel segments where segments where flow flow

convergenceconvergence is evidentis evidentconvergenceconvergence is evidentis evident

Cooper Creek Floodplain, Durham DownsCooper Creek Floodplain, Durham DownsN t h th d th t th t h l t t d tNote how many there are, and that the waterholes start and stop.

Sand dunesSand dunesCooper Cooper CreekCreekCreek Creek

FeaturesFeatures

AnastomosingAnastomosingAnastomosing Anastomosing channelschannels

Mud braidsMud braids

Rivers Planforms

???

channels

A t iAnastomosing channels

Q: Braided and Anastomosing channels coexisting??

Braided channels

gA: Yes…due to the floodplain sediments … and channels operate at different flow

regimes

Clay-rich soil aggregates behave as gg gsand grains BUT: Lower density

Hi hl d bl

Ripples

Highly durable Variable sediment size More mobile Lower entrainment

threshold RESULT: Coexistence of mud braids and anastomosing channels

Dunes

Sediment splays

Mt Howitt site

Mt Mt HowittHowitt: : B i dB i dBuried Buried

ChannelChannelChannelChannel

Mt Howitt site

X1

X2Flow orientation 60m long

X1

X2

Mt Mt HowittHowittSiteSite

Mt Howitt Trench (X1Mt Howitt Trench (X1--X2)X2)X1 X2

Mud Unit

Sand UnitAv. Width=60mAv. Bankfull Depth=5-6mPalaeodischarge=80 m3/s

Sand Unit

Example:Example: Transect through point barTransect through point barpp g pg p

X2Meandering ChannelMeandering Channel

X1X2

‘Mt Howitt‘Mt HowittTransect’Transect’

gg

Point barPoint bar

Geomorphologist’s footprint

Trench sites

Scroll bars

Fl liFlow line

Acquired WVAcquired WV--2 Site Imagery2 Site Imagery

Reticulate channels

‘Poached Anastomosingegg’ sand dunes

Anastomosing channels

Site C: Equalization (Bands 8,

S ll Bq ( ,

1, 2)

- Scroll bars are evident

Scroll Bars

and highlighted by

vegetation growth in red

with more recent grass

growth showing up in

blblue-green.

Anastomosing channels N

Site D: Gaussian enhancement (Bands 8 1 2)

Poached egg sand dune (Bands 8, 1, 2)

-Located in SW corner of image between 2 ‘poached

sand dune

Buried channel egg’ floodplain dunes - Dark band in the centre locates a buried mud channel between the dunes.

Buried channel

channel between the dunes. - Trees (acacias) are evident on the dunes themselves.

R d t th d f- Red tone on the edge of the dunes extending away from the dunes represents more established recent growth whilst the blue green hue is the most recent growth probably grasses or floodplain herbage

Poached egg N

floodplain herbage. sand dune

Reticulate channels distorting the floodplain

surface as they flow S-SW

N

Small sinuous channel flowing S towards the

N

flowing S towards the ‘poached egg’ sand dunes showing well watered and drier

sections

Site E: Equalization (Bands 1, 6, 7)-The small, intricate distributary/reticulate channels fan out from the sinuous channel to the north across the floodplain. Buried

Buried channels

y pchannels are readily evident.- Bright blue areas equate to the sand dune areas identified earlier, whilst deeper blue is of water evident in the sinuous channel. - Buried channels are not as pronounced but still clearly visible.- Green tinges showing most recent vegetation growth, whilst red tinge on the floodplain is from vegetation growth that has resulted from earlier inundation/wetting.

Group 2: Aeolian/Fluvial Group 2: Aeolian/Fluvial Interactions:Interactions:Interactions:Interactions:

Sporadically distributed floodplain Sporadically distributed floodplain dunesdunesdunesdunes

Elevations: <10mElevations: <10m Distinctive indurated Distinctive indurated areolaareola

(‘ h d d ’)(‘ h d d ’)(‘poached egg dunes’)(‘poached egg dunes’) Q: Q: Do dunes pre/post date muddy Do dunes pre/post date muddy

floodplain?floodplain?pp

Emergent Aeolian Dune (Poached Egg Dune) Emergent Aeolian Dune (Poached Egg Dune) and muddy Floodplainand muddy Floodplainy py p

1.5 kms

Chookoo Site:Chookoo Site: Location:Location: ~1.5km from ~1.5km from

western floodplainwestern floodplainwestern floodplain western floodplain marginmargin

3 deflated dunes 3 deflated dunes surrounded by surrounded by floodplain mudsfloodplain muds

Ephemeral channels Ephemeral channels located between located between dddunesdunes

Chookoo transect:Chookoo transect:2 2 km long (22 auger2 2 km long (22 auger2.2 km long (22 auger 2.2 km long (22 auger holes & 3 trenches)holes & 3 trenches)

The many faces of The many faces of th i Ch kth i Ch k

Wet

the main Chookoo the main Chookoo Channel:Channel:Channel:Channel:

First impressions First impressions -- waterhole?waterhole?B tB t h ll ( 1h ll ( 1 2 d )2 d ) But…But…shallow (~1shallow (~1--2m deep), 2m deep), saucer shaped depressionsaucer shaped depression

Scour channels formed by flowScour channels formed by flow

Dry

Scour channels formed by flow Scour channels formed by flow constriction/confinementconstriction/confinement

Located between Chookoo Located between Chookoo dunesdunes Photos of main Chookoo Channel Photos of main Chookoo Channel

between Dunes 1 & 2between Dunes 1 & 2

Chookoo Transect: Dunes 1, 2 & 3Chookoo Transect: Dunes 1, 2 & 3

FlFlFlowFlow

Channel straightening=Channel straighteningf (flow confinement; concentrated flow energy; less cohesive sediment)

Chookoo Channel Development:Chookoo Channel Development:

Durham Downs Dunes (another source bordering dune system)

7.7ka

Durham Dune, Cooper CreekDurham Dune, Cooper Creek

15.9ka

49.6ka

52 0ka2.5ka

52.0ka

86.7ka 116ka

96ka

118ka

205ka

96ka

172ka

Proposed Proposed Cooper ModelCooper ModelCooper Model:Cooper Model:

Shows link betweenShows link betweenShows link between Shows link between dune development and dune development and former laterally activeformer laterally activeformer laterally active former laterally active sandsand--load channelsload channels

Increasing aridity sinceIncreasing aridity since Increasing aridity since Increasing aridity since late Stage 5 resulted in late Stage 5 resulted in planform changes andplanform changes andplanform changes and planform changes and dune developmentdune development

SomeoneSomeoneSomeone Someone outstandingoutstandingoutstanding outstanding

‘in’‘in’ thetheinin the the field ???field ???field…???field…???

1974 Flood1974 Flood••WindorahWindorah

Windorah to Nappa Merrie: ~400 kmWindorah to Nappa Merrie: ~400 km

Max Q @ Windorah:Max Q @ Windorah:Max Q @ Windorah: Max Q @ Windorah: 25,000 m25,000 m33 ss--11

Max Q @ Nappa Merrie: Max Q @ Nappa Merrie: 5 000 m5 000 m33 ss--11

60 km

5,000 m5,000 m33 ss 11

A di iA di i

Transmission losses: 70%Transmission losses: 70%

L kL k

Average conditionsAverage conditions

Flood travel times: 25 Flood travel times: 25 –– 30 days30 daysLake Lake

Yamma YammaYamma Yamma Maximum temperatures: Maximum temperatures: Summer ~40Summer ~40ooC C

Image shows Cooper in flood, early 1974, the largest on recordImage shows Cooper in flood, early 1974, the largest on record

Evaporation: 2500Evaporation: 2500--3000 mm a3000 mm a--11

So whatSo whatSo what So what happens to happens to

all this waterall this waterall this water all this water as it moves as it moves

slowly slowly downstream.downstream.

Surely aSurely aSurely a Surely a great deal of great deal of

it mustit mustit must it must evaporate?evaporate?

Solute changes downstreamSolute changes downstreamWindorah Nappa Merrie 400 km downstream

If transmission losses are d e to e aporation then chlorideIf transmission losses are d e to e aporation then chlorideIf transmission losses are due to evaporation, then chloride If transmission losses are due to evaporation, then chloride should should increase with increasing dissolved salt …increase with increasing dissolved salt …

but but the opposite is evident here. the opposite is evident here.

Question?

Where does all the Where does all the floodwater go? floodwater go?

Answer:

During large floods, kmDuring large floods, km33 of fresh water are of fresh water are transferred from the surface to the neartransferred from the surface to the near--transferred from the surface to the neartransferred from the surface to the near--

surface aquifers (~10m) beneath the Channel surface aquifers (~10m) beneath the Channel Country floodplains of western QldCountry floodplains of western QldCountry floodplains of western Qld Country floodplains of western Qld

Waterhole cross-section during periods of no-flow

Levee bank Floodplain

FLOODPLAIN MUDstagnant water(impermeable)

5 m

stagnant water

SAND SHEET(hi hl bl )

impermeable clay seal deposited from suspension when flow ceases.

(highly permeable)

GROUNDWATER

Waterhole cross-section during periods of flow

Levee bank Floodplain

FLOODPLAIN MUD(impermeable)

5 m stagnant water

flow scours

SAND SHEET(hi hl bl )

clay lining

(highly permeable)

GROUNDWATER

Waterhole cross-section during periods of flow

Levee bank Floodplain

FLOODPLAIN MUD(impermeable)

5 m

S d

SAND SHEET(hi hl bl )

Scour erodes into sand unit

(highly permeable)

GROUNDWATER

Waterhole cross-section during periods of flow

Levee bank Floodplain

FLOODPLAIN MUD(impermeable)

5 m

S d

SAND SHEET(hi hl bl )

Scour erodes into sand unit

(highly permeable)

GROUNDWATER

Drill Hole

FLOODPLAIN CLAY

ALLUVIAL SAND0.24 mS/cm

~7 m

1 6 mS/cmWATER TABLE

1.6 mS/cm

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22(m)

ChookooChookooDDDune Dune

ComplexComplex

Freshwater inputs

Water tableWater table

TDS TDS (Total Dissolved Solids: mg/L) (Total Dissolved Solids: mg/L) variations variations in groundwater in groundwater along the Goonbabinna Waterhole to Chookoo Sandhill site along the Goonbabinna Waterhole to Chookoo Sandhill site

transect. transect.

5 DERM ‘Questions of Interest’:5 DERM Questions of Interest :1.1. Riparian ecosystem functionRiparian ecosystem functionp yp y

Significant connection between waterholes and the shallow near-surface (~10m depth) aquifer High flows: scour and penetration of large quantities of

flood waters into sub-surfaceL fl l t d i Low flows: seal regenerated; some minor seepage may still exist but not a lot

Fresh water lens nearest to waterholes decreasingFresh water lens nearest to waterholes decreasing with distance from waterhole

Eucalypts have an important roleEucalypts have an important role

5 DERM ‘Questions of Interest’:5 DERM Questions of Interest :2.2. Natural erosion rates and change in ratesNatural erosion rates and change in ratesgg LocalisedLocalised erosion within waterhole banks around erosion within waterhole banks around

tree roots but not widespread or rapidtree roots but not widespread or rapid Some erosion Some erosion occurs between occurs between dunes dunes

Refer to Refer to ChookooChookoo SandhillSandhill sitesite Dunes concentrate overland flow and results in Dunes concentrate overland flow and results in

channel straightening and bed scour channel straightening and bed scour Results in possible waterhole development andResults in possible waterhole development and Results in possible waterhole development and Results in possible waterhole development and recharge locationrecharge location

Aeolian-fluvial surface i t tiinteraction

5 DERM ‘Questions of Interest’:5 DERM Questions of Interest :2.2. Natural erosion rates and change in ratesNatural erosion rates and change in rates Cooper Creek is a large sedimentary sump Cooper Creek is a large sedimentary sump

accreting over a vast floodplainaccreting over a vast floodplain Western f/p accreting 4x faster than eastern Western f/p accreting 4x faster than eastern

f/p over last ~75,000 years due to subsidence of f/p over last ~75,000 years due to subsidence of floodplain in Wfloodplain in Wfloodplain in Wfloodplain in W

Invasion of western tributaries, dunefields & Lake Invasion of western tributaries, dunefields & Lake Yamma Yamma by Cooper mudsYamma Yamma by Cooper mudsYamma Yamma by Cooper mudsYamma Yamma by Cooper muds

E tributary fans extend onto eastern Cooper f/pE tributary fans extend onto eastern Cooper f/p

Western migration of floodplain?Western migration of floodplain?g pg p

Western vs Eastern f/p accretion ratesWestern vs Eastern f/p accretion ratespp

E 0 4 0 6 /100

W: 1.9-2.3cm/100yr

E: 0.4-0.6cm/100yr

OI Stages and depositional processes:OI Stages and depositional processes:

Aeolian SandsAeolian Sands

Fluvial MudsFluvial Muds

Fluvial SandsFluvial Sands

Palaeoclimatic Interpretations:Palaeoclimatic Interpretations: Australia’s midAustralia’s mid--Quaternary climate much wetter than Quaternary climate much wetter than

presentpresentpresentpresent Large, laterally active sandy bedload channels Large, laterally active sandy bedload channels

dominated pluvials 5 & 7dominated pluvials 5 & 7 (fluvial activity peak mid(fluvial activity peak mid Stage 5)Stage 5)dominated pluvials 5 & 7 dominated pluvials 5 & 7 (fluvial activity peak mid(fluvial activity peak mid--Stage 5)Stage 5)

Stage 5: not as fluvially energetic as previous pluvialsStage 5: not as fluvially energetic as previous pluvialsA li ti it i t ifi d f St 4 dA li ti it i t ifi d f St 4 d Aeolian activity intensified from Stage 4 onwardsAeolian activity intensified from Stage 4 onwards

Stage 3 < fluvially energetic than Stage 5Stage 3 < fluvially energetic than Stage 5 Stage 2 drier than Stage 4Stage 2 drier than Stage 4

Sand bed channels reverted to low energy, mudSand bed channels reverted to low energy, mud--dominated dominated anastomosing system anastomosing system (prevails to present)(prevails to present)

Stage 1 < fluvially energetic than Stage 3 < Stage 5Stage 1 < fluvially energetic than Stage 3 < Stage 5

5 DERM ‘Questions of Interest’:5 DERM Questions of Interest :

33 Sediment trapsSediment traps riparian vs floodplainriparian vs floodplain3.3. Sediment traps Sediment traps –– riparian vs floodplain riparian vs floodplain grasslands?grasslands?

B th l Both apply Floodplain: low angle levee banks formed along

anastomosing channelsanastomosing channels Riparian: high suspended sediment loads in

channels Overall, the Cooper is a large sump that is

slowly accreting with mud

5 DERM ‘Questions of Interest’:Q4.4. What flow change would have a measurable What flow change would have a measurable

impact on the geomorphology of Cooperimpact on the geomorphology of Cooperimpact on the geomorphology of Cooper impact on the geomorphology of Cooper Creek?Creek? Low and high flow connection between floodplain Low and high flow connection between floodplain

and shallow groundwater aquifer Little impact due to large flows but Little impact due to large flows but …

reactivation of sandier channels may result waterhole development between dunes waterhole development between dunes

Impacts on reduced low flows may have considerable consequences on the waterholesq Reduced stability of banks if vegetation does not cope

with prolonged salinity increases

5 DERM ‘Questions of Interest’:5 DERM Questions of Interest :5. Geomorphic considerations relevant to Water p

Resources Plan and Wild Rivers?Recharge characteristics of waterholes (including g ( g

scourholes) must be protected Recharge potential of non-permanent waterholes often

located between sand dunes (eg: Chookoo) Relevance in supporting waterhole-reliant ecosystems

during ‘boom-bust’ ecological cyclesduring boom bust ecological cycles ‘Poached egg’ dunes are:

Sites of scour hole formation and recharge zones (dual roles)

Possible recharge points but only in large floods

5 DERM ‘Questions of Interest’:5 DERM Questions of Interest :5. Geomorphic considerations relevant to Water p

Resources Plan and Wild Rivers?Reduced/less frequent low flows may have q y

considerable consequences on waterholes Cooper is the most hydrological variable river in the

world (Diamantina, Paroo and Cooper in Top 6: Puckridge, 1999)

Reduced stability of steep sided waterhole banks if Reduced stability of steep sided waterhole banks if vegetation is not able to survive increased salinity

Subsurface salinity levels would increase during prolonged dry spells which may impact Coolibahs, River Red Gums, etc

Future Geomorphological

ResearchCoongie Lakes

Research

Concluding comments:Concluding comments: Most extensive fluvial TLMost extensive fluvial TL--based record dating back to based record dating back to

midmid--QuaternaryQuaternary Oldest TL dated fluvial deposit in Australia (SR @ 27m = >700 ka)Oldest TL dated fluvial deposit in Australia (SR @ 27m = >700 ka)

Last 3 interglacials Last 3 interglacials (ie: ‘wetter phases’)(ie: ‘wetter phases’) progressively progressively drying with decreasing fluvial activitydrying with decreasing fluvial activitydrying with decreasing fluvial activitydrying with decreasing fluvial activity Stages 1 < 3 < 5 …Stages 1 < 3 < 5 … (Re: less fluvially activity)(Re: less fluvially activity) Australia drying out in alternating fashion over past several glacial cyclesAustralia drying out in alternating fashion over past several glacial cycles

Does fluvial max Does fluvial max postpost--datedate temp max? If so, by how temp max? If so, by how much? Is the next pluvial episode yet to come??much? Is the next pluvial episode yet to come?? ie: Holoceneie: Holocene increased fluvial activity in Stage 1??increased fluvial activity in Stage 1?? ie: Holocene ie: Holocene … increased fluvial activity in Stage 1??… increased fluvial activity in Stage 1??

Westward f/p migrationWestward f/p migration Possible impacts of subsidence/neotectonicsPossible impacts of subsidence/neotectonics

Climate change most sign. factor influencing Cooper Climate change most sign. factor influencing Cooper Creek palaeohydrology & sediment transportCreek palaeohydrology & sediment transport

ACSC Websited /www.usq.edu.au/acsc

More information?More information?More information?More information?Dr Jerry MaroulisDr Jerry Maroulis Dr Jerry MaroulisDr Jerry Maroulis•• Deputy Director, ACSCDeputy Director, ACSC

Email:Email:•• maroulis@usq.edu.aumaroulis@usq.edu.au

Phone:Phone:07 46312340 040875216507 46312340 0408752165•• 07 46312340; 040875216507 46312340; 0408752165

Visit the ACSC website:Visit the ACSC website: Visit the ACSC website:Visit the ACSC website:www.usq.edu.au/acscwww.usq.edu.au/acsc