IMPACT OF ENVIRONMENTAL CHANGES ON THE ECO-HYDRO-MORPHOLOGY OF A RIVER SYSTEM Italian Partners
Argentine Partners
Università di Bologna
Universidad National del Litoral
Università di Padova
Universidad National de La Plata
Università della Tuscia
Universidad National de Córdoba
GIORNATE DEL CUIA IN ARGENTINA Sessione Ecosistemi e Sviluppo Sostenibile dei Sistemi Rurali
AIMS • Analysis of the sediments yield in the Upper Bermejo and Pilcomajo basins. • Development of a database of field data. • Modelling of the eco-hydro-morphological changes of the fluvial environment due to climatic changes. • Analysis of the interactions between velocity field of the water, sediment transport and morphology of the river cross-sections.
METHODS OF THE STUDY • Application of mathematical models for simulating the production of sediments and the behaviour of the river at different scales, in terms of sediment transport and morphological evolution. • Application of new and own-developed methods for estimating and mapping velocity fields, secondary currents, shear stress velocities, bed apparent velocities, concentration and grain size composition of sediments. • Use of Acoustic Doppler Current Profile (ADCP) to measure morphology, sediment transport and currents.
PARANÁ RIVER
The Paraná River is located in south Central South America, running through Brazil, Paraguay and Argentina for some 4880 km. It is second in length among South American rivers. Santa Fe Buenos Aires
It merges first with the Paraguay River and then farther downstream with the Uruguay River to form the Río de la Plata and empties into the Atlantic Ocean.
MAIN FEATURES OF THE PARANÁ RIVER • • • • • •
Mean discharge Bed composition Channel planform pattern Mean widths Mean depths Wash load transport
= = = = = =
18000 m3/s fine & medium sands anabranching with meandering thalweg 600 - 3000 m 5 - 30 m 50-80% of total sediment transport
SEDIMENT YIELD IN THE UPPER BERMEJO AND PILCOMAYO BASINS
Universidad Nacional de La Plata, Argentina D. Brea, P. Spalletti, M. Irigoyen
METHODOLOGY Gavrilovic Erosion Potential Method Parametric distributed model for estimating the total annual sediment yield of a watershed. • land use • climatic factors • topographic features • surface geology and soils
Effective Sediment Transported
Retention Coefficient
Application: Upper Bermejo and Pilcomayo basins
CLIMATIC DATA
PRESENT Scenario Temperature [1960-1990]
PRESENT Scenario Precipitation [1960-1990]
CLIMATIC DATA
FUTURE Scenario LMDZ boundary conditions
FUTURE Scenario ECHAM boundary conditions
RESULTS RESULTS
MATHEMATICAL MODELLING OF THE EVOLUTION OF THE PARANA’ RIVER
Università degli Studi di Padova, Italia M. Nones, G. Di Silvio
Università di Bologna, Italia M. Guerrero, M.G. Gaeta, A. Lamberti
MATHEMATICAL MODELS Mathematical simulations were performed aiming to study the recent evolution of Middle and Lower Paranà River, occurring during the XX century due to hydrological variability, by applying various models at different time- and-space scale. These research results are useful for predicting the future morphological evolution of the river in the light of climatic changes.
1-D SIMULATIONS
HEC-RAS & LUFM
2-D SIMULATIONS
MIKE 21C
1-D SIMULATIONS These models simulate the river hydro-morphodynamics in the longitudinal direction and are referred to as one-dimensional (1-D) models. These models are able to simulate long period, ranging from 100 to 1000 years, that depends on the resolution of the topographic representation: the higher is the resolution, the shorter is the simulated period. The two applied models differ in resolution and in the assumed scheme and maximum simulation time.
1-D SIMULATIONS : HEC-RAS The Hec-Ras model reproduces a reach of about 1000 km and is based on a bathymetric survey made by the Instituto Nacional del Agua during the 1970s. The hydrodynamic is calibrated in terms of width of the floodplains and roughness of the river bed, on the basis of water level data available for the period 1994-1999. The validation of the morphodynamic is made in terms of sediment transport and water flow, with a sediment transport formula calibrated with the data of the humid period of the XX century (1930-1970).
1-D SIMULATIONS : LUFM The Local Uniform Flow Morphodynamic model is a own-developed model, and assuming some simplifications, as the validity of the local uniform flow at the analysis scale. We couple this model with a quasi 2-D description of the river crosssection for describing the interactions between the liquid flow and the variations of the river width. The evolution of the cross-section is simulated at seasonal scale, for reproducing the variation of the width correlated with the seasonality; while the longitudinal evolution is simulated at larger time-scale, for describing the long-term variations of the bottom profile.
1-D SIMULATIONS : XX CENTURY The variation of the bottom profile described by the two models are quite similar: the upper part of the Lower Paranà is a depositional zone, while the Middle Paranà appears quite stable or slightly erodible.
1-D SIMULATIONS : XXI CENTURY For forecasting the hydrology of the XXI century we use two series of liquid flow, resulted from the hydrological distributed model VIC, that was applied to the La Plata Basin by the University of Buenos Aires, assuming as input the results of the Regional Climate Models (RCM) PROMES by the University of Castilla and La Mancha (Spain) and RCA by the Swedish Meteorological and Hydrological Institute. The RCMs were forced with boundary conditions obtained from HadCM3 and ECHAM5 Global Climate Models (GCM), and the A1B scenario for CO2 emission was considered. The effective discharge of the past century (17000 m3/s) increases of 50% for the PROMES (25000 m3/s) and 30% for RCA (21000 m3/s) time-series.
1-D SIMULATIONS : XXI CENTURY The future evolution of the bottom profile is quite similar between the two scenarios: the upper part of the Lower Paranà remains a depositional zone, while the Middle Paranà appears stable or slightly erodible.
2-D SIMULATIONS We study the reach between Pto. San Martin and Rosario. Applying MIKE21C, we carried out a sensitivity analysis on the sediment transport with the aim to reproduce the morphological changes that were observed in the period 1954-1976. This analysis bears out the river mechanisms that were fostered by climate and land use changes by means of changed regime of liquid discharge.
2-D SIMULATIONS : MORPHODYNAMICS CALIBRATION The morphodynamic calibration was carried out on the 1954-1976 period, reproducing the Carlota Island formation, which was formed in the middle of the active part of the river as the consequence of a deposition process that took place at Lower Paranà. The Carlota sub-reach significantly changed during the XX century in a way that is representative of Lower Paranà morphodynamics. The morphodynamic calibration consists of a sensitivity analysis that was performed on final morphology by modifying the sediment transport portion which is deviated from stream flow direction due to secondary flows and transversal slope of the river bed. Three simulations were performed with an increasing influence of bed transversal slope in deviating sediment direction by means of the calibration parameter G.
2-D SIMULATIONS : MORPHODYNAMICS CALIBRATION The figure shows the initial bathymetry and the final morphology as resulting with different G values together with 1976 historical margins.
2-D SIMULATIONS : FUTURE SCENARIOS The figure shows the initial bathymetry (a) and the final morphology (c for RCA and d for PROMES) as resulting for the two future time series and for the 30 years run with the last decade conditions (b).
ESTIMATION OF BED SEDIMENT TRANSPORT WITH ADCPS IN A LARGE SAND BED RIVER, RÍO PARANÁ, ARGENTINA Universidad Nacional del Litoral, Argentina R. N. Szupiany, F. Latosinski, M. L. Amsler
Universidad Nacional de Córdoba, Argentina C. M. Garcia
Università di Bologna, Italia M. Guerrero, M. Nones
WHY DEVELOP METHODOLOGIES WITH ADCPs?
FIELD WORK
• Traditional measurements methods are: • time-consuming, • expensive, • labor intensive, • with limited spatial resolution. • Only two sediment gauging stations with no systematic measurements are used
EQUIPMENTS SINGLE BEAM ECHOSONDER Morphology
DEPTH-INTEGRATING SEDIMENT SAMPLER Suspended Sediment concentration and size characteristics
1000 kHz SonTek ADP 1200 kHz TRDI ADCP Flow structure and bed suspended sediment transport
RTK – DGPS Leica
RELATION BETWEEN ACOUSTIC & SCATTERS ADCP emits an acoustic pulse and then listen for the return echo from the acoustic backscatterers present in water column (sediment and other material)
SUSPENDED SEDIMENT CHARACTERISTICS
Paraná and Colastiné rivers WASHLOAD: Clay and silts (65-95 % depending on the annual period) diameter mm 6 % - 16-31 µm 60.8 % - 8-16 µm 33.2 % - 4-8 µm diámetro en mm
0.001
0.01
0.1
100
90 80
QUARTZOSE SANDS: Mean diameter: 100 µm diámetro en mm
diameter mm 0.001
0.01
0.1
1
más fino %%finest
70 60 50 40 30
10
20
100
10
90 0 10
80 70
% fino %más finest
9
8
7
6
5
4
3
diámetro Φ (diámetro en mm = 2 Diameter
2
-Φ)
Scanning Electron Microscope
60 50 40 30
P3 ROS P4 ROS
P1 ROS P2 ROS 3 28 COL 002 130 COL
20 10
2 102 COL 2 211 COL
0 10
9
8
7
6
5
4
3
2
1
diámetro Φ (diámetro en mm = 2 Diameter
0 -Φ)
-1
-2
-3
100 µm
100 µm
1
SUSPENDED SEDIMENT CHARACTERISTICS
Paraná and Colastiné rivers
Cs (mg/l)
Cw (mg/l)
Cpom (mg/l)
Maximum
91
337
0.880
Minimum
6
85
0.003
Mean value
18
173
0.217
Cs: Cw: Cpom:
Suspended sand concentration Silt and Clay concentration Suspended organic particle concentration
CALIBRATION RESULTS
CALIBRATION OF A SONTEK 1000 kHz ADP
STUDY SITE 0
NORTH
2 km
TIN S LA CO
PA
Zone A
N A R
A
R E V RI
Par an
áR
iv e r
Bermejo River
SANTA FE CITY
ER V I ER
Zone B
Santa Fe City San Martín City
PARANA CITY
METHODOLOGY
• 29 verticals with a depth-integrating sampler • Simultaneously, fixed-vessel measurements were made with the ADP The verticals were located to get as wide a range of sand concentration as possible at the measured river stages.
CALIBRATION RESULTS
Relationship between corrected ADP backscatter and measured washload concentrations
Relationship between corrected ADP backscatter and measured suspended sand (10log(Cs))
Relationship between corrected ADP backscatter and measured suspended sand concentrations
CALIBRATION RESULTS CALIBRATION OF A Teledyne RDI 1200 kHz ADCP
STUDY SITE
METHODOLOGY
• 42 verticals with a depth-integrating sampler • Simultaneously, fixed-vessel measurements were made with the ADCP The verticals were located to get as wide a range of sand concentration as possible at the measured river stages.
CALIBRATION RESULTS Calibration: silt and clay concentrations vs backscatter
Calibration: sands concentrations vs backscatter
y = 0.129*x – 9.51 R2=0.91 Log10 (M ) = 0.1(RL + 2TL) + K T
USE OF CALIBRATION AND ADCP VELOCITY DATA TO COMPUTE SUSPENDED BED SEDIMENT TRANSPORT (ADCP RDI Teledyne 1200 kHz)
APPLICATION
SUSPENDED BED SEDIMENT TRANSPORT: Traditional method
Gss = ∑ Gss ,i
Gss ,i = U i * Ai * CSS meas ,i ( ADCP)
( samples)
Ai = hi * bi Pr ogri − Pr ogri −1 Pr ogri +1 − Pr ogri bi = + 2 2
SUSPENDED BED SEDIMENT TRANSPORT: Moving-ADCP method
Gss ,sup = ∑ Gss ,i sup Gss ,i sup = Gss ,i (H NM / H B ) H NM = Blanking + Draft
Gss ,i = U i *Ω i * CSS calc ,i ( ADCP)
(Calibration)
Ω i = (Pr ogri 2 − Pr ogri 1 )H B Gss meas = ∑ Gss ,i
Gss = Gss ,sup + Gss , meas
COMPARISON BETWEEN THE TWO METHODS Section
Colastiné Colastiné R3 R6 R7
Gss (ADCP) kg/s 68 43 378 465 1082
Gss (traditional Difference method) kg/s % 80 -15 56 -23 320 18 507 -8 1070 1
High Resolution
USE OF ADCPs TO COMPUTE BEDLOAD SEDIMENT TRANSPORT (ADCP RDI Teledyne 1200 kHz)
Va mean = 0.054 m/s
Va mean = 0.040 m/s
Va mean = 0.03 m/s
Bed Load Transport from Dune Migration
gsf = β (1 − P )H d U d gsf = 0.092 kg s −1 m −1 Bed Load Transport Rate
gsf = ρ s (1 − P )d a va 2650 kg/m³ 0.4
from (a = (b
(b
0.054 m/s (BT-ADCP)
d a = 1.08mm ≈ 2d 65 ( Einstein,1950) (active transport layer depth)
(a
FUTURE WORKS Field and laboratory works Collaboration between: • FICH-UNL (Szupiany R.; Latosinski F.) • UNIBO (Guerrero M.; Nones M.) • USGS
Field work sites:
FUTURE WORKS Field and laboratory works Laboratory work: •
• •
Università di Bologna (UNIBO laboratory, Italy): 3 m depth vertical tank for sediment mixing and hydraulic flume for bed load and suspended sediment large concentrations. UNIBO horizontal flume: length of 18 m and cross-section is 0.75 wide and 1 m depth Norwegian University of Science and Technology (NTNU, Norway). Large depth (2 m) hydraulic flume.
INVITATION
22 & 23 March,
2013
Santa Fe, FICH-UNL
Abstracts: 21/09/12
[email protected] www.fich.unl.edu.ar/meh2013/
Thanks!
[email protected] [email protected] 