simone bizzi in collaboration with:
DESCRIPTION
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?. - PowerPoint PPT PresentationTRANSCRIPT
Simone Bizzi
In collaboration with:Dr Andrea Nardini Technical Director of CIRF (Italian
Centre for River Restoration)
Model and evaluate geomorphology under different
catchment management strategies
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
National Level
Regional/River Basin Level
Catchment/Coastal cell level
Community Level
Site/System level
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
Is it the database suitable?
Problems to face
•Limited information in the variables
•Dynamic system in space and time
•Typology: Every river has its behaviour
Index
(Targets – Geomorphological Features)
Model approach
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
National Level
Regional/River Basin Level
Catchment/Coastal cell level
Community Level
Site/System level
Modelling Evaluating
Information
(Causal Factors)
Evaluation
Model approach
Modelling Evaluating
Phase 1: A cluster analysis able to find pattern in the data and structured them in a way suitable for the evaluation
Information
(Causal Factors)
EvaluationIndex
(Targets – Geomorphological Features)
Model approach
Phase 2: A classification model able to give an output suitable for an evaluation
Modelling Evaluating
Information
(Causal Factors)
EvaluationIndex
(Targets – Geomorphological Features)
RHS site
Geomorphological Features (targets):
•Numbers of Bars
•Numbers of Pools and Riffles
•Type of Bank vegetations
•Numbers of woody debris
•Bankfull width
CONCEPTUALIZATION
RHS site
Natural variables (Causal Factors )
•Slope
•Flow Regime
•Geology
CONCEPTUALIZATION
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 )
d1
d2
d3
d4
RHS site
CONCEPTUALIZATIONRHS sitesLevel of modification in the sites and upstream (Causal Factors)•Hard Modification :
ResectioningBank and channels reinforcementsEmbankments
•Soft Modification: WeirsBridgesford..
•Culverts
d1
d2
d3
d4
RHS site i
CONCEPTUALIZATION
xi (t+1)= f( uRHS,i(t),ucat,i(t), Nat(t) )
xi = f( uRHS,i,ucat,i ,Nat)
STEADY STATE
Clustering Step
Clustering Step
Natural Variables (VERTICAL path) Vs Anthropogenic Variables (HORIZONTAL path)
Clustering Step
C1
C3
C2
Riffles and
Pools
Bars Bank vegetation
Mean C1 1.74 1.32 17.5
Mean C3 4.78 9.15 25
Model capability
?
?
C1
C3
Arable Urban Land
Vegetated
Grass land
Mod. Up stream
Mod. in the site
C1 mean 47 7 23 20 10 16
C1 std 15 7 9 10 6 11
C2
SCENARIOSrate (% in Class
C1)
Scenario zero (untouched) 100
Reduced Hard Interventions in the site
(80%) 85
Reduced Hard Interventions in the site
and up-stream (80%) 66
Land Use changes (-50% Arable - 20% Urban
->Vegetated) 87
All together 24
?
?
C1
C3
C2
Model capability
Scenarios
rate (% in Class
C1)P(x/C1)
P(x/C2)
P(x/C3)
Scenario zero (untouched) 100 0.9 0.05 0
Reduced Hard
Interventions in the site and up-
stream (80%) 66 0.59 0.27 0.03
?
?
C1
C3
C2
Model capability
• The weakness of a site specific approach
• Flexible Geomorphological tool at national level
• RHS limits
Conclusions
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!