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:•• [email protected]@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