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Model and evaluate geomorphology under different catchment management strategies. Simone Bizzi In collaboration with: Dr Andrea Nardini Technical Director of CIRF (Italian Centre for River Restoration). What is Geomorphology?.
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Model and evaluate geomorphology under different catchment management strategies Simone Bizzi In collaboration with: Dr Andrea Nardini Technical Director of CIRF (Italian Centre for River Restoration)
What is Geomorphology? “..the study of sediment sources, fluxes and storage within the river catchment and channel over short, medium and longer timescales and of resultant channel and floodplain morphology” (Newson and Sear 1993)
Geomorphology and river management? • Annual expenditure on Flood Defence > £500 million • WFD requirement to maximize habitat quality
Aims of the research Model and evaluate geomorphological features under different catchment managements strategies
Why River Habitat Survey? • 10 years of experiences and more than 10000 samples only in England and Wales • Assessments and decisions are taken using this dataset • Feedbacks for the next versions
Problems to face • Limited information in the variables • Dynamic system in space and time • Typology: Every river has its behaviour
Model approach Modelling Evaluating Information (Causal Factors) Index (Targets – Geomorphological Features) Evaluation • More experiences in literature Geomorphology (CAESAR,REAS, HEC-RAS ..) • They require detailed and specific data • Most of the time not catchment scale • Evaluation phase most of the time is missing
Model approach Modelling Evaluating Information (Causal Factors) Index (Targets – Geomorphological Features) Evaluation Phase 1: A cluster analysis able to find pattern in the data and structured them in a way suitable for the evaluation
Model approach Modelling Evaluating Information (Causal Factors) Index (Targets – Geomorphological Features) Evaluation Phase 2: A classification model able to give an output suitable for an evaluation
CONCEPTUALIZATION • Geomorphological Features (targets): • Numbers of Bars • Numbers of Pools and Riffles • Type of Bank vegetations • Numbers of woody debris • Bankfull width RHS site
CONCEPTUALIZATION • Natural variables (Causal Factors ) • Slope • Flow Regime • Geology RHS site
CONCEPTUALIZATION • Percentage of Land Use in the sub-catchment (Causal Factor ): • Vegetated • Urban • Improved Grass Land • Arable RHS site
CONCEPTUALIZATION Percentage of area in the sub-catchment obstructed by dams or artificial reservoirs (Causal Factor ) RHS site
CONCEPTUALIZATION • RHS sites • Level of modification in the sites and upstream (Causal Factors) • Hard Modification : • Resectioning • Bank and channels reinforcements • Embankments • Soft Modification: • Weirs • Bridges • ford.. • Culverts d4 d3 d2 RHS site d1
CONCEPTUALIZATION xi (t+1)= f( uRHS,i(t),ucat,i(t), Nat(t)) STEADY STATE xi = f( uRHS,i,ucat,i,Nat) d4 d3 d2 RHS site i d1
Clustering Step Natural Variables (VERTICAL path) Vs Anthropogenic Variables (HORIZONTAL path)
Clustering Step C1 C2 C3
Model capability C1 ? ? C2 C3
Model capability C1 ? ? C2 C3
Model capability C1 ? ? C2 C3
Conclusions • The weakness of a site specific approach • Flexible Geomorphological tool at national level • RHS limits
Future Directions • Assessing the feasibility to add biology • Developing a “site specific” case study to overcome some limitations intrinsic in the national level • Analysing the level of “integrability” between these two different approach
Thank you for your attention! s.bizzi@sheffield.ac.uk