How To Develop An International Framework For Analysis Of Fluvial Morphological Processes

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ADVANCES IN RIVER SCIENCE CONFERENCE

Swansea, 18-21 April 2011

A new methodological framework

for stream hydromorphological

assessment, analysis and

monitoring (IDRAIM)

Massimo Rinaldi

1 _{, Nicola Surian}

2 _{, Francesco Comiti}

3 _,

Martina Bussettini

4

1

_{Dipartimento di Ingegneria Civile e Ambientale, Università di Firenze}

2

_{Dipartimento di Geografia, Università di Padova}

3

_{Facoltà di Scienze e Tecnologie, Libera Università di Bozen-Bolzano}

4

_{Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA), Roma}

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Context

EC Water Framework

Directive: hydromorphology

as one component of stream

quality conditions

EC Flood Directive:

identification of measures to

mitigate floods and related

hazards

Potentially conflicting objectives:

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IDRAIM

framework

(sistema IDRomorfologico di valutazione, AnalisI e

Monitoraggio dei corsi d’acqua)

ISPRA, Istituto Superiore per la Protezione e la Ricerca

Ambientale (Italian Environmental Agency)

Aim:

to develop an overall

methodological

framework for analysis of fluvial

morphological processes

, integrating

objectives of quality and safety, according to

WFD

and

Flood Directive

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Specific characteristics

- Integration of morphological quality and fluvial

dynamic hazard

- Italian (european) context

- Emphasis on geomorphic processes, sediment

connectivity, trajectories of changes

- Application to identification of possible strategies /

actions for river management (target: public

agencies)

Characteristics

IDRAIM

framework

Existing methods

River Styles Framework (Australia) , Fluvial Audit

(UK), SYRAH (France)

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Stage 1: General setting and initial segmentation

Stage 2: Present morphological conditions and past channel evolution

Stage 3: Future trends

Stage 4: Integrated management

2.2 Evaluation and analysis of morphological quality

2.1 Analysis of present and past conditions

(A) Sediment sources; (B) Sediment connectivity; (C) Stream power; (D) Transport capacity; (E) Trajectories of changes; (F) Causes of channel evolution

2.3 Evaluation and analysis of morphological dynamics hazard

2.4 Synthesis of problems

Morphological Quality Index Morphological dynamics hazard index

(B) Implications on morphological quality

3.1 Analysis of future scenarios

(C) Implications on hazard

3.2 Monitoring and post-monitoring evaluation

4.1 Priorities

4.2 Conflicts and integration of objectives

4.3 Classification, analysis and management of HMWB 4.4 Monitoring post - interventions

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IQM (Morphological Quality Index)

1. It is

not a Physical Habitat Assessment

method

2. Designed for

WFD

but

not exclusive

3. Designed for

geomorphologists

4. It evaluates the

morphological quality

(independently from ecological implications)

Main characteristics and novelties

Approaches and methods

(1) Remote sensing and GIS analysis

(2) Field survey

Recently approved as hydromorphological assessment

method by Italian Legislation on WFD implementation

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1954

2003

Incision

Clay outcropping

Terrace

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Reference conditions:

dynamic equilibrium

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Phase 1: Segmentation

(1) Physiographic units; (2) Confinement; (3)

Channel morphology; (4) Other discontinuities

Reach: scale of application

of IQM (1 – 5 km)

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Phase 2: Morphological assessment

1. Continuity

A. Longitudinal

B. Lateral

2. Morphology

A. Channel pattern

B. Cross-section

C. Substrate

3. Vegetation

Functionality

Channel

changes

Artificiality

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Functionality Continuity

F1 Longitudinal continuity in sediment and wood flux F2 Presence of modern floodplain

F3 Hillslopes – stream connection F4 Processes of bank retreat

F5 Presence of a potentially erodible corridor

Morphology

Channel pattern

F6 Bed configuration – valley slope

F7 Forms and processes typical of the channel pattern F8 Presence of typical fluvial forms in the alluvial plain Cross-section configuration

F9 Variability of the cross-section Bed substrate

F10 Structure of the channel bed

F11 Presence of in-channel large wood

Vegetation

F12 Width of functional formations in the fluvial corridor F13 Linear extension of functional vegetation

Artificiality

Upstream alteration of longitudinal continuity

A1 Upstream alteration of channel-forming discharges A2 Upstream interception of sediment transport

Alteration of longitudinal continuity in the reach

A3 Alteration of channel-forming discharge in the reach

A4 Interception of sediment transport in the reach A5 Crossing structures

Alteration of lateral continuity

A6 Bank protections A7 Artificial levees

Alteration of channel morphology and/or substrate

A8 Artificial changes of river course

A9 Other structures of alteration of channel profile and/or substrate

Interventions of removal

A10 Sediment removal A11 Wood removal A12 Vegetation cutting

Channel changes

V1 Changes in channel pattern V2 Changes in channel width V3 Bed-level changes

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Functionality –

F1

: Longitudinal continuity in

sediment and wood flux

Class A

Class B

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Channel changes -

V1

: Changes in channel pattern

Class A

Class B

Class C

1954

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1. Very good

(IQM = 0.85 – 1.0)

IQM

=0.87

2. Good

(IQM = 0.70 - 0.85)

IQM

=0.79

IQM

=0.60

3. Moderate

(IQM = 0.50 – 0.70)

4. Poor

(IQM = 0.3 – 0.5)

IQM

=0.43

5. Very poor

(IQM = 0 – 0.3)

IQM

=0.04

Morphological Quality Index

:

IQM=1-IAM

Morphological Alteration Index:

IAM= Stot / Smax

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Unconfined Semiconfined Confined

IQM applications

VERY GOOD GOOD MODERATE POOR VERY POOR VERY GOOD GOOD MODERATE POOR VERY POOR VERY GOOD GOOD MODERATE POOR VERY POOR VERY GOOD GOOD MODERATE POOR VERY POOR

Confined

Braided – wandering

unconfined

Single-thread

unconfined

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0,00 0,10 0,20 0,30 0,40 0,50 0,60 0,70 0,80 0,90 1,00 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 IQM V IQM A IQM F

IQM applications

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