GEOMORPHIC RESPONSE TO EXTREME FLOOD EVENTS IN...

Scuola di Dottorato in Scienze della Terra, Dipartimento di Geoscienze, Università degli Studi di Padova – A.A. 2014-2015

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GEOMORPHIC RESPONSE TO EXTREME FLOOD EVENTS IN ALLUVIAL RIVERS

Ph.D. candidate: MARGHERITA RIGHINI, II course

Tutor: Prof.. NICOLA SURIAN

Co-Tutor: Prof.. FRANCESCO COMITI, Dr. LORENZO MARCHI, Prof. ELLEN WOHL

Cycle: XXIX

Abstract

Extreme floods are one of the major natural hazards that affect Italian territory and their frequency has increased over the last

years. Thus geomorphological hazards due to channel dynamics should be taken into account, specifically in alluvial rivers, as

a possible cause of severe damage to human property and infrastructure. This research aims to assess quantitatively

geomorphic effects due to extreme events in alluvial and semi-alluvial rivers in different physiographic and climatic settings.

The research is based on integration of field surveys and remote sensing, GIS and statistical analyses to obtain a quantitative

analysis of morphological changes and to correlate such changes with possible controlling factors (e.g. confinement,

channel gradient, stream power, and unit stream power). Further objective of the research is to develop and test conceptual

and empirical models to improve our capability of predicting channel dynamics and related geomorphological hazard during

extreme events.

Full Report

Introduction

Infrequent, high-magnitude floods can lead to sudden, dramatic channel changes in alluvial and semi-

alluvial channels. A number of previous geomorphological studies argued about the role of events with

high magnitude and low frequency in conditioning channel form (Baker, 1977) in order to evaluate the

ability of a flood to be geomorphically effectiveness and their capacity to modify the channel morphology

in a very short time period (Wolman and Miller, 1960; Miller, 1990; Costa and O'Connor, 1995; Phillips,

2002; Magilligan et al., 2015). Whereas few recent studies have focused on the role of such events in

terms of channel dynamics hazards.

Therefore besides hydraulic hazard, geomorphological hazard owing to channel dynamics should be

taken into account, specifically in alluvial and semi-alluvial rivers. Geomorphic effectiveness of extreme

or catastrophic events can be explain as the amount of work done during a flood (Wolman et al., 1960) or

by the degree of landscape modification caused by a flood (Miller at al., 1987). However quantifying

geomorphic changes is much more difficult than quantifying the hydraulic forces (Costa et al., 1995) due

to the conjunction of multiple variables and the different boundary conditions. Although several studies

have documented the effects of catastrophic events (Magilligan, 1992; Hooke at al., 2000; Merritt at al.,

2003; Kale et al., 2007; Langhammer, 2010; Krapesch et al., 2009; Milan, 2012; Dean et al., 2013),

nowadays an overall quantitative approach that related geomorphic response to extreme floods of

different alluvial rivers is not available.

The main purposes of this work are (i) to provide a quantitative assessment of geomorphic effects due

to extreme events (recurrence interval > 100 years) in some alluvial and semi-alluvial rivers and (ii) to

identify a range of potential controlling factors of channel changes. The research is carried out in different

physiographic and climatic settings including several study rivers located in Northern Apennines

(Tuscany), Northeastern Sardinia, Venetian Prealps, Rocky Mountain National Park (Colorado, USA).

The research focuses on (i) the quantitative assessment of geomorphic effects and their spatial

distribution (ii) the evaluation and the improvement of the current understanding of the main controlling

factors affecting the geomorphic response to extreme floods (iii) the identification of relationships

between controlling factors and channel changes and (iv) the development of conceptual and empirical

models to be tested to a wider data set in order to assess and predict fluvial dynamics and related

geomorphological hazard in order to build up tools enabling to predict where major geomorphic changes

occur during an extreme flood.


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Methods

The methodological approach is based on a quantitative analysis of morphological changes carried out

by photo interpretation conducted in a geographic information system (GIS), using the pre-flood and

post-flood aerial photographs or satellite images and Digital Elevation Models, integrated with field

surveys (i.e. geomorphological survey, grain size analysis, topographic survey) and statistical analysis.

The overall procedure includes:

1. Morphological characteristics and delineation of spatial units. General setting of the rivers

physical conditions and a first division of the watershed in macro-areas (physiographic units) and

in corresponding macro-reaches (segments) is carried out (Fig. 1a). The definition of

homogeneous reaches (with lengths normally of the order of 1-5 km) is achieved taking into

account channel morphology, lateral confinement (i.e. confinement index and confinement

degree) (Brierley and Fryiers, 2005), hydrologic discontinuity, channel slope, artificiality (Rinaldi

et al., 2013) (Fig. 1b). For a more accurate analysis of relation between channel changes and

controlling factors, reaches were divided into sub-reaches having a constant slope. Finally sub-

reaches are defined in order to attain a more accurate analysis by using the method proposed by

Vocal Ferencevic and Ashmore (2012). This method is based on constant horizontal increments

(Knighton, 199; Jain at al 2006) and it permitted to extract a satisfactory quality DEM-derived

slope for the stream power calculation. Indeed the definition of sub-reaches is essentially based on

the definition of the proper minimum distance to obtain constant slope depending on the DEM

resolution and by considering hydrologic discontinuities on the main stream (e.g., presence of

tributaries) (Fig. 1c).

a) b)

c)

Figure 1. Example of delineation of spatial units in the Teglia River (Magra River catchment):

physiographic units and segments (a); homogeneous reaches (b); constant slope sub-reaches (c).

2. Quantitative analysis of channel response. The geomorphic channel responses due to the events in

terms of banks erosion, channel aggradation and incision, wood transport, hillslope failure were

mostly analyzed in the field in a qualitative way. Otherwise the dominant geomorphic change

observed in most of the study rivers is channel widening. For this reason the channel width

changes are measured in detail in GIS by comparing aerial photographs or satellite images taken

before and after the flood (Fig. 2). In order to quantify the channel widening, it is expressed as a


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width ratio, i.e. channel width after/channel width before the flood (Krapesch et al., 2011) and it

is used as a parameter to describe the morphodynamic activity in terms of lateral erosion,

avulsions and overbank scouring (Krapesch et al., 2009) at reach and sub-reach scale.

a) b) Figure 2. Example of comparison between satellite images pre (a) and after (b) the flood in the

Posada River (Sardinia) at sub-reach scale.

3. Controlling factors. A range of several morphological and hydraulic variables are considered as

possible controlling factors which could explain the channel response to high-magnitude flood

events. The geomorphic factors could be: in partly confined and unconfined reaches the extent of

floodplain, stated in terms of confinement index Ci, define as the ratio between the floodplain

width and the channel width representing the natural constrain to channel widening; channel

gradient; channel sinuosity; potential significant tributary sources, in terms of lateral sources and

the associated sedimentary links that could have significant impact on river bed sediment texture

and, in turn, on channel form (Rice, 1998); artificial structures which may hinder channel lateral

mobility; sediment supply, in terms of landslide areas effectively coupled to the main channel

network (Cavalli et al., 2013, Crema et al., 2015); the role of both riparian arboreal vegetation and

arboreal vegetation included in the floodplain. The possible hydraulic variables are driving forces

strictly related to stream energy and flood power, such as: the cross-sectional stream power Ω

(Wm-1

), defined as the rate of potential energy expenditure per unit length of channel; the unit

stream power ω (Wm-2

) , defined as rate at with potential energy is supplied to a unit area of the

bed (Knighton, 1999). Unit stream power has been shown to have an important influence on many

aspects of the fluvial system as the geomorphic effectiveness of flood discharge (Baker et al.,

1987; Magilligan, 1992), also as a reasonable predictor for river width changes during extreme

floods (Krapesch et al., 2011). For instance, Magilligan (1992) identified stream power value of

300 W m-2

as the potential minimum threshold, above which significant geomorphic adjustment is

likely to occur in unconfined channel reaches. Furthermore two different values of stream power

could be consider by taking into account pre or post flood channel width in order to understand

which one gives a better explanation of channel response, especially in those case where the width

ratio is particularly high. However peak instantaneous stream power could not adequately quantify

the spatio-temporal distribution of river energy expenditure along a channel reach, but the

geomorphic work could be also influenced by the flow duration and total energy expenditure

(Costa and O’Connor, 1995). Indeed two main parameters derived from the stream power

hydrograph could be take into account, such as: event energy expenditure Ωe (J), computed as the

area under the stream power hydrograph from the start to the end of the runoff event; geomorphic

energy expenditure Ωg(J), define as a proportion of Ωe above Miller-Magilligan critical stream


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power threshold of 300 W m-2

referred and associated with energy available for geomorphic work

in unconfined and/or partially-confined channels. In addition another adimensional parameter (i.e.,

geomorphic index, GI=Ωg⁄Ωe) that combines flood-flow duration, stream power per unit area and

threshold for alluvial channel erosions is developed and tested and taken into account as a

predictor of geomorphic effectiveness for high magnitude floods.

4. Statistical analysis: morphological changes and controlling factors correlations. Statistical analysis

is carried out to explain channel response to the flood event, by exploring the relationship between

geomorphic changes occurred and controlling factors. Different statistical tools could be applied

to investigate which set of controlling factor gave best explanation of channel response (e.g.,

ANOVA analysis, simple regression, multiple regression). The statistical analysis could be

applied both at reach and sub-reach scale.

5. Conceptual/empirical models. As a result of correlations between channel response and possible

controlling factors for each case of study, conceptual and empirical models will be developed in

order to assess new tools for a better understanding and prediction of fluvial dynamics and

morphological responses to such extreme events.

Study Rivers

Teglia and Geriola Rivers

Teglia and Geriola Rivers are tributaries of the Magra River located in Northern Tuscany. Their

catchment have an area of 43.1 km2 and 8.2 km

2 respectively and their courses have a total

length of

approximately 14 km and 7 km. On October 25th

2011 Teglia and Geriola catchments were affected by an

extreme meteorological event with hourly rainfall intensities up to 25 mm/h and a peak in rain

accumulation of approximately 330 mm in 13 hours with an estimated recurrence time of more 100 years.

The study focuses on reaches affected by evident and significant geomorphic responses in terms of

channel widening that occurred along most of the partly-confined and unconfined reaches (i.e. 6.6 km in

the Teglia River and 5.8 km in the Geriola River).

Posada and Mannu di Bitti River

The Posada River and its tributary Mannu di Bitti are located in Northeastern Sardinia. Their

catchments have an area of 680 km2 and 302 km

2 respectively and their courses have a length of

approximately 88 km and 59 km. On November 18th

2013 Posada and Mannu di Bitti catchments were

affected by an extreme meteorological event with hourly rainfall intensities up to 100 mm/h and a peak in

rain accumulation up to 250 mm in 24 hours. The study focuses on reaches affected by evident and

significant geomorphic responses in terms of channel widening occurred along most of the confined,

partly-confined and unconfined reaches (i.e. 22.5 km in the Posada River, upstream of Maccheronis dam;

18.2 km in the Mannu di Bitti River).

Lierza River

The Lierza River is a tributary of the Soligo River located in the Venetian Prealps. The catchment has

an area of 8 km2 and the river has a length of 19.5 km. On August 2

nd 2014 the Lierza catchment was

affected by an extreme meteorological event with a peak in rain accumulation of approximately 58 mm in

2 hours. The study focuses on the reach upstream of Molinetto waterfall affected by geomorphic

responses in terms of channel widening occurred along most of the reach 1.8 km long. For this case study the geomorphic analysis are carried out mainly by field surveys because of the small size of the channel.

North Saint Vrain Creek

The St. Vrain Creek is a tributary of the South Platte River, approximately 51.8 km long, in north

central Colorado in the United States. The catchment has an area of 216 km2

and it drains Wild Basin


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within the southeastern portion of Rocky Mountain National Park near Allenspark. In September of 2013,

the Colorado Front Range foothills experienced an extensive period of rainfall that culminated in a major

flood that peaked in many streams on Friday, the 13th. Rainfall depths of up to 457 mm were recorded

over a 10 day period, with a large proportion of the rainfall falling over a 36 hour period. Peak flow

estimates about 700 m3/s, with return interval >200-year (S.E. Yochum, 2015; Chignell S.M. et al.,2015).

During the 2013 event the combination of debris flows and flooding was responsible for eight victims and

caused extensive damage to buildings, highways, railroads, and infrastructure (J.A. Coe et al.,2014).

Results and research plan for next years

In the second year the work on Magra tributaries (i.e., Teglia and Geriola Rivers) was almost

concluded by encompassing in the ultimate work all the data collected and elaborated for six tributaries of

Magra River (i.e., Teglia, Geriola, Mangiola, Osca, Pogliaschina and Gravegnola River) in collaboration

with a large group of researches belonging to the Faculty of Science and Technology, Free University of

Bozen-Bolzano (Italy), the Department of Earth Sciences, University of Florence (Italy), the CNR IRPI,

Padova (Italy) and the Department of Land, Environment, Agriculture and Forestry, University of Padova

(Italy). An integrated approach was deployed to study this flood, including (i) analysis of channel width

changes by comparing aerial photographs taken before and after the flood, (ii) estimate of peak discharges

in ungauged streams, (iii) detailed mapping of landslides and analysis of sediment connectivity with

channel network. Considering a large range of morphological characteristics, and specifically the

variability in channel slope, and also to achieve a better understanding about the relationship among

channel widening and the controlling factor, the whole dataset was analyzed considering two subsets both

at reach and sub-reach scale, the first including reaches with a slope 4% (non-steep slope), the other subset with reaches having a slope ≥ 4% (steep slope). Channel widening was defined at reaches and sub-

reaches scale and it occurred in 35 reaches out of 39. In reaches with non-steep slope (< 4%) average and

maximum width ratio was 5.2 and 19.7 (i.e. channel widened from 4 m to 82 m), respectively; in steep

reaches (slope ≥ 4 %) widening was slightly less intense. Finally the correlation between the channel

widening and seven controlling factors was explored at sub-reach scale (i.e.,157 sub-reaches) by using

multiple regression models. The analysis of controlling factors was carried out taking into account four

geomorphic and three hydraulic factors. The geomorphic factors were: channel slope, as a proxy of

stream morphology; confinement index; artificial structures which may obstruct channel lateral mobility;

sediment supply, in terms of landslide areas effectively coupled to the main channel network. Stream

energy was analyzed taking into account three hydraulic variables closely related to flood power: cross-

sectional stream power (Wm-1); unit stream power (Wm-

2), obtained by dividing the stream power by

channel width measured before and after the flood (ω=Ω/Wbefore and ω=Ω/Wafter). In the steep sub-reaches, characterized by higher confinement, stream power, unit stream power (considering pre-flood channel

width), and lateral confinement showed good relationships with channel widening (i.e. width ratio) and

coefficients of multiple determination R2 ranging between 0.44 and 0.67 were obtained. The models for

the non-steep sub-reaches provided a lower explanation of widening variability, being R2 between 0.32

and 0.40; in these reaches a significant relation, although weak, between sediment supply from hillslopes

and channel widening was found. Results pointed out that hydraulic variables are not sufficient to explain

channel response to extreme floods and inclusion of other factors, e.g. lateral confinement, is needed to

increase explanatory capability of models. Concerning hydraulic variables, this study showed that unit

stream power, considering channel width before the flood, has stronger relations with channel widening,

in comparison to stream power and, in particular, to unit stream power calculated with post-flood channel

width. This could suggest that most of width changes occurred after the flood peak. These results suggest

that the widening processes is essentially controlled by two factors, flood power and valley confinement

(Fig.3) (Surian et al., 2015).


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Non-steep slope Steep slope

a) d)

b) e)

c)

Figure 3. Simple regression models between width ratio and controlling factors. Only significant factors

of the two best models obtained by multiple regression analysis are shown: (a), (b), and (c) refer to sub-

reaches with non-steep slope; (d) and (e) to sub-reaches with steep slope.

It is significance noting that flood duration above a critical threshold could be a variable that would

increase very likely the robustness of models in these sub-reaches. For this reason models were improved

by introduction of the geomorphic index, the event energy expenditure and geomorphic energy

expenditure above Miller-Magilligan critical stream power threshold of 300 Wm-2

together with peak

stream power calculated with pre-flood channel width as possible controlling factors of channel widening

for five of the six studied tributaries. Four different multiple regression models were carried out on the

non-steep and steep sub-reaches including geomorphic variables (i.e., confinement index and sediment

supply) in all models and taking into account separately independent variables related to stream energy

and flood duration. Preliminary results showed that the input of controlling factors related to flood

duration provided a larger explanation of channel widening compared with the previous models. In more

detail in non-steep sub-reaches they gave higher coefficients of multiple determination and models

included peak stream power calculated with pre-flood channel width, the geomorphic energy expenditure

and total energy expenditure turned out the best fit with R2=0.53, R

2=0.52, R

2=0.55 respectively. In these


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sub-reaches the most influential explanatory variables for the response variable (i.e., channel widening)

were the confinement index (R2=0.31), the peak stream power calculated with pre-flood channel width

(R2=0.37) and the total event expenditure energy (R

2=0.31). The analysis also highlighted that the

sediment supply was significant in all models. An increasing in value of coefficients of multiple

determination occurred also in the steep sub-reaches models and the best fit was given by the model

included the total energy expenditure (R2=0.68). In steep sub-reaches models the most influential

explanatory variables for the channel widening were the confinement index (R2=0.43), the peak stream

power calculated with pre-flood channel width (R2=0.52) and the total event expenditure energy

(R2=0.55). However in these models the sediment supply was not statistically significant.(Fig.4)

Non- steep slope Steep slope

a) d)

b) e)

c) f)

Figure 4. Simple regression models between width ratio and the most influential controlling factors for

no-steep sub-reaches (a), (b), and (c) and steep sub-reaches (d), (e) and (f).

Field surveys including geomorphological survey, GPS survey and grain-size analysis were carried

out in the Posada and Mannu di Bitti Rivers on April 2015. Three reaches for each study river were


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surveyed in detail. Geomorphological surveys included observations and mapping, by using ArcPad on a

GPS device, of the geomorphic responses to the flood (e.g., bank erosion and scouring, overbank

deposition on the floodplain, sediment input), channel bedforms, floodplain extension, bedrock outcrops,

riparian and floodplain vegetation and the presence of artificial structure along the rivers corridor. 11

grain-size samplings were collected by using the pebble count approach along transects (Bunt et al., 2001)

on the surveyed reaches. Therefore the definition of spatial units (i.e., physiographic units, segments,

reaches and sub-reaches), channel confinement, channel gradient were carried out by using remote

sensing and GIS tools. The analysis was performed on two sets of satellite images of the rivers before

(2011) and after the flood (2014). Five homogeneous reaches were defined for both Posada and Mannu di

Bitti rivers by taking into account channel morphology, lateral confinement (i.e., confinement index and

confinement degree), hydrologic discontinuity, channel slope and artificiality. Furthermore reaches were

divided in 28 and 20 sub-reaches, having a constant slope, respectively for Posada and Mannu di Bitti

rivers by using the method proposed by Vocal Ferencevic and Ashmore (2012). Because DEM resolution

was rather low (10 m), sub-reaches length turned out to be of the order of 700-1000 m (Fig. 5).

Figure 5. Slope profile computed using different distances. Application of measuring channel slope from

a low DEM resolution (10m) the GIS‐based tools method proposed by Vocal Ferencevic and Ashmore (2012) for Posada and Mannu di Bitti rivers. This method is based on constant horizontal increments

(Knighton, 199; Jain at al 2006) and it permitted to extract a satisfactory quality DEM-derived slope for

the stream power calculation. Indeed considering slope over short distances (i.e., 100-500 m) can result in

extreme detail and may be subject to significant error as well as measuring slope over too large a distance

can create a widespread slope and smoothes real channel features and considerable local channel scale

slope variation (i.e., 1500 m).

The second half of the second year (June-December 2015) has been completed abroad, at the

Geosciences Department, Colorado State University (Colorado, USA) under the supervision of Prof.


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Ellen Wohl. During the period abroad, in addition to the outlined PhD project, several activities were

carried out:

▬ Fieldwork in the Rocky Mountain National Park (Colorado, USA) with Professor José A. Ortega

from the Departamento de Geología y Geoquímica, Universidad Autónoma de Madrid, Spain. The

field work aimed to examine waterfalls on the western side of Rocky Mountain National Park to

evaluate whether drainage area or bedrock properties as reflected in joint characteristics correlate

more strongly with the location and characteristics of individual waterfalls (Fig.6). June 2015.

Figure 6. Example of studied waterfall and bedrock characteristics on the western side of Rocky

Mountain National Park.

▬ Fieldwork on the Corral and Haghe Creek (Poudre, Colorado, USA). The fieldwork aim was to

settle some stage discharge gauging along the Corral and Haghe Creek with professor Ellen Wohl.

July 2015.

Figure 7. Settlement of stage discharge gauging along the Corral and Haghe Creek.

▬ Flume experiment at the Engineering Research Center at CSU (Colorado, USA). This activity was

conducted with Dr. Lina Polvi Sjöberg, a researcher from Umeå University, Sweden. It aimed to

understand the natural condition of semi-alluvial streams in northern Sweden that have been

heavily impacted by timber-floating in order to predict channel geometry and to determine

whether there was any self-organization of bedforms (Fig. 7). August-September 2015.


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Figure 8. Flume built at the Engineering Research Center at CSU.

▬ Fieldtrip to Poudre River (Colorado, USA). The fieldtrip consisted in a survey of a cross section

on the Poudre River in order to measure the active channel width, the high-flow channel width,

the flow depth, the particle size in the channel, the flow velocity and the channel roughness.

Furthermore the data collected were used to estimate low and high discharge for the surveyed

cross section using both the continuity equation and the Manning equation. Moreover different

approaches were applied to estimate roughness n for the channel (i.e., the Manning equation, the

Limerinos equation, Jarret equation, visual estimation using both a table and the Cowan method)

to compare n values obtained with each of these methods for the same reach channel, and

determine the effect of these varying n values on calculation of flow velocity and discharge (Fig.

9). September 2015.

a) b)

F ig Figure 9. Poudre River upstream view (a); measuring of channel width and flow depth on the

surveyed cross section (b).

▬ Fieldtrip to Pawnee Buttes (Colorado, USA). The fieldtrip concerned the examination of the

arroyo formation in the Pawnee Grassland region, northeast of Fort Collins, in order to address the

regional and local-scale control in channel incision, the specific process through which incision

occurred, the rate of incision and his variation through time by doing several observations and

measurements. Basically the field activities consisted in the measurement of valley floor and

channel slope in both actively incising and stabilized reaches, noting vegetative, topographic,

sedimentary characteristics of the basin and measuring channel characteristics (i.e., cross-sectional

area, width/depth ratio, bed gradient, grain size) (Fig. 10). October 2015.


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a) b)

c)

Figure 10. Survey in an actively incising reach (a), (b) and stabilized reach (c).

▬ North Saint Vain Creek (Colorado, USA). Firstly a literature review about the flood that affected

the North St. Vain Creek was carried out. Also a fieldwork took a place on October 2015, under

the supervision of Prof. Sara Rathburn (Geosciences Department, Colorado State University), in

order to assess the main geomorphic effects due to the 2013 flood. The survey consisted in a

geomorphological survey of the highly confined and partly confined channel mostly focused on

the assessment of debris flow, bank failure, wood transport and jams, aggradation/incision and

sediment supply, GPS survey, measuring of channel width by using the laser distance meter (Fig.

11). October 2015.

a) b) c)

Figure 11. North Saint Vain Creek: highly confined reach (a); bank failure and sediment input on

the highly confined reach (b); partly confined reach (c).

Future steps of this research include: (i) definition of the main geomorphic and hydraulic controlling

factors in the Posada and Mannu di Bitti River (e.g., stream power, unit stream power, valley

confinement, channel sinuosity, channel gradient, potential significant tributary sources of sediment,

vegetation) and identification of relationships between those controlling factors and morphological

changes; (ii) definition of the main driving factors of the 2014 flood affected the Lierza River and

assessment of possible correlations with channel responses; (iii) quantitative analysis of geomorphic

response by remote sensing analysis in the St. Vrain Creek and definition of possible correlation with

controlling factors. As for the St. Vrain Creek, the analysis will mainly addresses to: assessment of

geomorphic channel response by comparing pre and post-flood Landsat imageries; estimation of the

volumetric change in sediment storage occurred during the 2013 flood from the difference in surface


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elevations from digital elevation models DoD (i.e., digital elevation model of difference); mapping of

debris flows; definition of the main controlling factors that drove the channel response to the 2013 flood;

iv) final comparison among the different geomorphic responses and controlling factors assessed in the

distinct studied rivers and development and test of conceptual and empirical models.

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22: 39-56

RINALDI M., SURIAN N., COMITI F., BUSSETTINI M. 2013. A method for the assessment and

analysis of the hydromorphological condition of Italian streams: The Morphological Quality Index

(MQI). Geomorphology 180-181: 96-108.

SURIAN N., RIGHINI M., LUCÌA A., NARDI L., AMPONSAH M., BENVENUTI M., BORGA M.,

CAVALLI M., COMITI F., MARCHI L., RINALDI M., VIERO A. 2015. Channel response to extreme

floods: insights on controlling factors from six mountain rivers in northern Apennines, Italy.

Geomorphology, in review.

VOCAL FERENCEVIC, M.V., ASHMORE, P. 2012. Creating and evaluating digital elevation model-

based stream-power map as a stream assessment tool. River Research and Applications 28, 1394–1416.

WOLMAN M.G., MILLER J.P. 1960. Magnitude and frequency of forces in geomorphic processes.

Journal of Geology 68: 54-74.

Yochum S.E. 2013. Colorado Front Range flood of 2013: peak flows and flood frequencies. Proceedings

of the 3rd Joint Federal Interagency Conference on Sedimentation and Hydrologic Modeling, April 19-

23, 2015, Reno, Nevada, USA.


14

SUMMARY OF ACTIVITY IN THIS YEAR

Courses:

F. FERRARESE, N. SURIAN: “Corso di GIS avanzato”, Dipartimento di Geoscienze, Università degli Studi di Padova.

February-March 2015; 18 hours.

K. THIELEN: "English as a 2nd Language-Academic ESL 6-2", FRCC Center for Adult Learning, Fort Collins

(Colorado,USA). June-July 2015; 28 hours.

K. THIELEN: "English as a 2nd Language-Academic ESL 6-2", FRCC Center for Adult Learning, Fort Collins

(Colorado,USA). August-December 2015; 64 hours.

J. ANDERSON: "STAT 511-Design and Data Analysis for Researchers I", Clark Building, Colorado State University, Fort

Collins (Colorado, USA). August-December 2015; 85 hours.

E. WOHL:“G 652 Fluvial Geomorphology”, Department of Geosciences, Colorado State University, Fort Collins (Colorado,

USA). August-December 2015; 45 hours.

Publications:

Rinaldi M., Amponsah W., Benvenuti M., Borga M., Comiti F., Lucìa, A., Marchi L., Nardi, L., Righini, M., Surian, N., 2015.

An integrated approach for investigating geomorphic response to extreme events: methodological framework and application

to the October 2011 flood in the Magra River catchment. Earth Surface Processes and Landforms, in review.

Surian N., Righini M., Lucìa A., Nardi L., Amponsah M., Benvenuti M., Borga M., Cavalli M., Comiti F., Marchi L., Rinaldi

M., Viero A. (2015). . Channel response to extreme floods: insights on controlling factors from six mountain rivers in northern

Apennines, Italy. Geomorphology, in review.

F. Comiti, M. Righini, L. Nardi A. Lucìa, W. Amposah, M. Borga, M. Cavalli, L. Marchi, M. Rinaldi, N. Surian. Channel

widening during extreme floods: how to integrate it within river corridor planning? 13th Congress INTERPRAEVENT 2016.

30th May-2nd

June 2016, Lucerne, Switzerland, submitted.

Other:

Seminar: M. G. MACKLIN: "Flooding in the Anthropocene: myths, mud, and metals", TESAF, Agripolis, Università degli

studi di Padova. 29th

April 2015.

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