SEDIMENTSEDIMENT PROCESSES IN PROCESSES IN TIDAL RIVERTIDAL RIVERBASINS, FLOOD PLAINS AND WETLANDS,BASINS, FLOOD PLAINS AND WETLANDS,

AND ANTHROPOGENIC EFFECTSAND ANTHROPOGENIC EFFECTS

What is a TIDAL RIVER, orWhat is a TIDAL RIVER, orTIDEWATER? It is a river or streamTIDEWATER? It is a river or streamin which the effects of the tide,in which the effects of the tide,decoupled from the penetration ofdecoupled from the penetration ofsalt, extends far upstream.salt, extends far upstream.

Wells, 1995Wells, 1995

Wells, 1995Wells, 1995

THE PARANÁ-LA PLATA SYSTEMTHE PARANÁ-LA PLATA SYSTEM

A NORTHERN VIEWA NORTHERN VIEW

THE PARANÁ-LA PLATA SYSTEMTHE PARANÁ-LA PLATA SYSTEM

A VIEW FROM THE SOUTH A VIEW FROM THE SOUTH

THE PARANÁ-LA PLATA SYSTEMTHE PARANÁ-LA PLATA SYSTEM

(BUENOS AIRES)(BUENOS AIRES)

Wells, 1995Wells, 1995

Main conclusions:Main conclusions:

a)a) The tideThe tidepropagates up topropagates up toZárateZárate, , ~100 km~100 kmupstreamupstream..

b)b) When the When the Paraná Paraná isisunder extremeunder extremeflooding (e.g.,flooding (e.g.,ENSO-triggeredENSO-triggeredflood), the effect isflood), the effect isnot visiblenot visible

TIDE VARIABILITY AT BUENOS AIRES (1982-83), i.e. during theTIDE VARIABILITY AT BUENOS AIRES (1982-83), i.e. during theoccurrence of the 1982-83 ENSO floodingoccurrence of the 1982-83 ENSO flooding

Exponetially smoothed tidal series

-100

-50

0

50

100

150

200

250

300

350

400

1 896 1791 2686 3581 4476 5371 6266 7161 8056 8951 9846 10741 11636 12531 13426 14321 15216 16111 17006

EXPONENTIALLY SMOOTHED TIDE VARIABILITYEXPONENTIALLY SMOOTHED TIDE VARIABILITY

0

10

20

30

40

50

Ga

ug

e h

eig

ht

(m)

0

0.01

0.02

0.03

0.04

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0.06

0.07

0.08

0 200 400 600 800 1000 1200 1400

Distance to mouth (Km)

So

pe

(m

/Km

)

THE PARANÁ-LA PLATA SYSTEMTHE PARANÁ-LA PLATA SYSTEM

CHARARACTERISTICS OF CHARARACTERISTICS OF TIDETIDE DOMINANTED ESTUARIES AND DOMINANTED ESTUARIES AND

TIDAL RIVERSTIDAL RIVERS::

•• They have a funnel shapeThey have a funnel shape

•• Bidirectional sediment transportBidirectional sediment transport

•• Mutually-evasive transport pathwaysMutually-evasive transport pathways

•• A tide- or density-induced turbidity maximumA tide- or density-induced turbidity maximum

•• Extensive regions of fine-grained sediment deposition (fluidExtensive regions of fine-grained sediment deposition (fluidmud)mud)

WellsWells, 1995, 1995

SSVVEERRNNRRIIVVEERRBBOORREE

In In BORESBORES or or EAGRESEAGRES, the leading edge of the incoming tide, the leading edge of the incoming tideforms a wave of water that travels up a river against the directionforms a wave of water that travels up a river against the directionof the current. They usually occur in areas with large tidal rangeof the current. They usually occur in areas with large tidal range((~2 m). A funnel-like shape increases the height of the tide.~2 m). A funnel-like shape increases the height of the tide.

QIANTANG TIDAL RIVER QIANTANG TIDAL RIVER BOREBOREThe worldThe world’’s largest bore: up to 9 m high,s largest bore: up to 9 m high, traveling at up to 40 Km per hour traveling at up to 40 Km per hour

IN ASIA, THE GANGES-IN ASIA, THE GANGES-BRHAMAPUTRA AND THEBRHAMAPUTRA AND THEINDUS ALSO SHOWINDUS ALSO SHOWBORESBORES

The AMAZON River has an up to 4 m high bore (know as theThe AMAZON River has an up to 4 m high bore (know as the““pororocapororoca””, from , from pororó-kápororó-ká or or ““big thunderbig thunder””). It travels up to 25). It travels up to 25Km/h and it has tsunami proportions. It occurs twice a year (Feb.-Km/h and it has tsunami proportions. It occurs twice a year (Feb.-Mar.). There is similar process in the Orinoco R.Mar.). There is similar process in the Orinoco R.

PARANÁ R. AT ROSARIO, PARANÁ R. AT ROSARIO, ~420 Km upstream the mouth~420 Km upstream the mouth

•• ANTHROPOGENIC EFFECTS?ANTHROPOGENIC EFFECTS?

•• CLIMATE CHANGECLIMATE CHANGEPERSPECTIVES?PERSPECTIVES?

•• USE OF THE LAND?USE OF THE LAND?

TENTATIVE LAYOUT FOR THE PAPER:TENTATIVE LAYOUT FOR THE PAPER:

•• Introduction.Introduction.

•• Tidal rivers: definitions (and examples). Tidal bores.Tidal rivers: definitions (and examples). Tidal bores.

•• Sediment processes (transport dynamics, etc.). CaseSediment processes (transport dynamics, etc.). Casehistories.histories.

•• The role of flood plains and wetlands in (tidal)The role of flood plains and wetlands in (tidal)sediment processes. Case histories.sediment processes. Case histories.

•• Human alterations of tidal rivers: causes and effectsHuman alterations of tidal rivers: causes and effects(?)(?)