ACROSS THE SCALES OF A RIVER BASIN 24th October 2017, V Jornadas de Ingeniería del Agua, A Coruña
Mário Franca River Basin Development chair group IHE Delft Institute for Water Education, The Netherlands
food & energy 60% more food :: 2050 50% more energy :: 2035 10% more water :: 2050
energy transition
FAO (2014)
ecological feedback
river basin uncertain climate Squarzoni P (2012) Saison Brune
safety
𝑔
Vegetated river (Saggiori, Rita, Santos, Ricardo, Ferreira 2008-15)
Gravity currents (Nogueira, Zordan, Venuleo, Theiler 2014-17)
Bedload (McKie, Plumb, Juez, Annable, 2016-17)
Suspended sediment (Juez, Navas-Montilla, Murillo, Liu, Shärer, Belghali, Thalmann, Bühlmann, Maechler, 2016-17)
leaves scale
patch scale
each process has a spatial memory persistence induces pack behaviour both determine the connectivity 6
Franca & Brocchini (2015), Turbulence in rivers in Rivers–Physical, Fluvial and Environmental Processes, Springer
SYSTEM-BASED RESEARCH (identifying a hierarchy of processes)
PROCESS-BASED RESEARCH (upscaling to feed system models)
9
® Stefan Haun
process
from processes to system
system
TRANSPORT OF SUSPENDED SEDIMENT Lateral cavities trap sediment; the amount of sediment trapped depends on their geometry and on the flow
Juez, Buehlmann, Maechler, Schleiss & Franca (ESPL) Juez, Thalmann, Schleiss & Franca (AdWR)
UPSCALING TO MEAN SCALES The fundamental equations are abridged to larger scales and all the small scale processes are incorporated in the basic transport equations by proper terms
14
2ND TOOL 1ST TOOL
Void function
Reynolds decomposition + Spatial decomposition of 𝑢
𝑢 = 𝑢 + 𝑢′
𝑢 = 𝑢 + 𝑢 + 𝑢′ 𝑢
Double-Averaged Navier-Stokes equations (DANS): 𝜕𝑢𝑗
NS:
𝜕𝑡
RANS:
DANS:
𝜕 𝑢𝑗 𝜕𝑡
𝜕 𝑢𝑗 𝜕𝑡
+ 𝑢𝑖
+ 𝑢𝑖
+
𝜕𝑢𝑗 𝜕𝑥𝑖 𝜕 𝑢𝑗 𝜕𝑥𝑖
=
=
1 𝜕𝑝 − 𝜌 𝜕𝑥𝑗
1 𝜕𝑝 − 𝜌 𝜕𝑥𝑗
𝜕 𝑢𝑗 𝑢𝑖 𝜕𝑥𝑖
1 𝜕𝛹 𝑢𝑗 𝑢𝑖 − 𝛹 𝜕𝑥𝑖
=
+𝜈
+𝜈
𝜕 2 𝑢𝑗 𝜕𝑥𝑖 𝜕𝑥𝑖 𝜕2 𝑢
𝑗
𝜕𝑥𝑖 𝜕𝑥𝑖
1 𝜕𝛹 𝑝 − 𝛹𝜌 𝜕𝑥𝑗
1 + 𝑝𝑛𝑗 𝑑𝑆 𝑆 𝜌∀𝑓 𝑖𝑛𝑡
+ 𝑔𝑗 −
1 𝜕 + 𝛹 𝜕𝑥𝑖
−
Reynolds-average
+ 𝑔𝑗
space-average
𝜕𝑢′𝑗 𝑢′𝑖 𝜕𝑥𝑖
𝛹 𝜈
𝜕 𝑢𝑗 𝜕𝑥𝑖
+ 𝑔𝑗 −
1 𝜕𝛹 𝑢′ 𝑗 𝑢′ 𝑖 𝛹 𝜕𝑥𝑖
𝜕 𝑢𝑗 1 𝜈 𝑛𝑖 𝑑𝑆 𝑆 ∀𝑓 𝑖𝑛𝑡 𝜕𝑥𝑖
Franca (2015) Upscaling approaches to turbulent environmental flows, Nicosia 2015, Rome 2016 https://www.researchgate.net/publication/283086313_UPSCALING_APPROACHES_TO_TURBULENT_ENVIRONMENTAL_FLOWS
Flow resistance in river with heterogeneous boundaries Franca M.J., Ferreira R.M.L. & Lemmin U. (2008) Advances in Water Resources
Impact of sand bedload in the oxygen distribution Ferreira R. L., Ferreira L. M., Ricardo A. M. & Franca M.J. (2010) River Research and Applications
Flow with emergent vegetation Ricardo A.M., Koll K., Franca M.J., Schleiss A.J. and Ferreira R.M.L. (2014) Water Resources Research Ricardo A.M., Franca M.J. & Ferreira R.M.L. (2016) Journal of Hydraulic Engineering
Shallow water equations for gravity currents Pokrajac D., Venuleo S. and Franca M.J. (2017) Journal of Hydraulic Research
RIVER BASIN SCALE System analysis at the basin scale allows to hierarchize control and driver processes
Pingshan (Upper Yangtze basin) 475 000 km2 (Iberian peninsula ≈ 582 000 km2)
more than 50 years of suspended sediment concentration (ssc) and discharge (Q)
suspended sediment concentration [mg/l]
Observations
Hysteresis:
Q1 = Q2
1000
ssc1 ≠ ssc2
WHAT IS THE REASON FOR THE ANNUAL HYSTERESIS?
10000
discharge [m3/s]
PREDICTION STRATEGIES: Date Discharge Combined (date and discharge)
suspended sediment concentration [mg/l]
Observations
Date
Discharge alone does not govern suspended sediment transport Amount of in-channel stored sediment explains hysteresis
Combined
Discharge
Matos, Hassan, Lu & Franca, Probabilistic prediction and forecast of daily suspended sediment concentration on the Upper Yangtze River, JGR–ES 1000
10000
1000
discharge [m3/s]
10000
A NEW LOOK MULTI-VARIABLE LANDSCAPES
® Sebastian Schwindt
Je~0.25! ~0.5 m ~2 m
head~175 m in 750 m!
Systems models, established at the envelope scales, are needed to plan and manage hydraulic infrastructures and water resources Smaller-scale processes, depending on their persistence and spatial memory, shape and determine the systems answers Identifying and understanding in detail the relevant drivers is an essential element to understand the entire system behaviour The mathematical interpretation of the topographies of a river basin reveal hotspots where opportunities and challenges regarding human usage, safety and ecology may occur
Mário J. Franca
[email protected] 
