Publications by category
Journal articles
Panici D (In Press). A theoretical analysis of the fluid-solid interactions governing the removal of woody debris jams from cylindrical bridge piers. Journal of Fluid Mechanics
Panici D, Kripakaran P (In Press). Assessing and mitigating risks to bridges from large wood using satellite imagery.
Proceedings of the ICE - Bridge EngineeringAbstract:
Assessing and mitigating risks to bridges from large wood using satellite imagery
The transport and accumulation of floating large wood (LW) debris at bridges can pose a major risk to their structural integrity. The impact forces arising from collisions of LW can cause significant damage to piers, and accumulations can constrict the flow and exacerbate scour at piers and abutments. Furthermore, LW accumulations increase afflux upstream of bridges, heightening flood risk for adjoining areas. Consequently, there is a need for a practical and rapid approach to identify bridges prone to LW-related hazards and to prevent the formation of LW accumulations. This paper proposes an approach based on satellite imagery to (i) quantify the risk of LW at a bridge structure and (ii) locate a LW-trapping system upstream of the identified vulnerable bridges to dramatically reduce risks of LW-related damage. This methodology is applied to major rivers in Devon (UK). 26 bridges were identified as at risk to LW with the majority prone to LW jams. Furthermore, satellite imagery was used to identify 12 locations for the potential installation of LW trapping systems for bridge protection. The results reported in this paper show that satellite imagery is a powerful tool for the rapid assessment and plan of mitigation measures for bridges at risk to LW.
Abstract.
Panici D (In Press). Characterising the importance of porosity of large woody debris accumulations at single bridge piers on localised scour. Water Resources Research
Panici D, Kripakaran P (In Press). Closure of “Trapping Large Wood Debris in Rivers: Experimental Study of Novel Debris Retention System”. Journal of Hydraulic Engineering
Panici D, Kripakaran P (In Press). TRAPPING LARGE WOOD DEBRIS IN RIVERS: EXPERIMENTAL STUDY ON a NOVEL DEBRIS RETENTION SYSTEM. Journal of Hydraulic Engineering
Pregnolato M, Giordano PF, Panici D, Prendergast LJ, Pina Limongelli M (2022). A comparison of the UK and Italian national risk-based guidelines for assessing hydraulic actions on bridges.
STRUCTURE AND INFRASTRUCTURE ENGINEERING Author URL.
Panici D (2021). An Experimental and Numerical Approach to Modeling Large Wood Displacement in Rivers.
Water Resources Research,
57(7).
Abstract:
An Experimental and Numerical Approach to Modeling Large Wood Displacement in Rivers
AbstractLarge wood (LW) is used for river restoration, aquatic habitat conservation, and flood control; however, it can pose a threat to human life and the built environment. The formation of LW jams, river management strategies, and design of mitigation measures crucially all depend on how the large wood is transported along a river. This paper experimentally analyses at laboratory scale the motion of natural sticks in a long stretch of a straight channel (16 m), when LW is released at different locations and with different flow conditions. Results show that instream large wood, following a transient motion shortly after being released at the water surface, tends to follow preferential patterns along the channel. Froude number and location of large wood input may provide an estimation of the LW location in downstream reaches. Several mechanisms of motion were observed, some of which were very common, including a frequent tendency to assume a tilted position with respect to the direction parallel to the flow. The experiments also suggest that theories on secondary cells responsible for channeling LW in preferential directions are incomplete. A new model, based on acceleration induced by hydrodynamic actions, has been established and proposed in this work, showing promising results and paving the way for the development of a comprehensive model for transport of large wood at the river surface in full‐scale applications.
Abstract.
Ebrahimi M, Djordjević S, Panici D, Tabor G, Kripakaran P (2020). A method for evaluating local scour depth at bridge piers due to debris accumulation.
Proceedings of the Institution of Civil Engineers - Bridge Engineering,
173(2), 86-99.
Abstract:
A method for evaluating local scour depth at bridge piers due to debris accumulation
a novel method for evaluating the effect of debris accumulation on local scour depth at bridge piers is introduced. The concept of a ‘debris factor’ is proposed to replace the current effective and equivalent pier width approaches that have been shown to overestimate debris-induced scour in many instances. The concept enables a simpler, more direct and realistic estimation of the change in local scour depth due to debris since it accounts for debris length (streamwise), width (spanwise) and thickness (depth wise), along with the influence of debris elevation in the flow; that is, it is applicable for free-surface debris, submerged debris or debris resting on the stream bed. The concept works with all existing local scour equations alongside other factors that influence scour depth such as flow angle of attack and pier shape. The mathematical model underpinning the proposed concept was derived through multiple linear regression of experimental data obtained at Exeter University and elsewhere. The proposed method was found to improve accuracy by at least 24% and 5% in comparison with the effective and equivalent pier width approaches, respectively. More importantly, the method is robust, providing highly consistent results with significantly less uncertainty.
Abstract.
Panici D, Kripakaran P, Djordjevic S, Dentith K (2020). A practical method to assess risks from large wood debris accumulations at bridge piers. Science of the Total Environment
Panici D, de Almeida GAM (2020). Influence of Pier Geometry and Debris Characteristics on Wood Debris Accumulations at Bridge Piers. Journal of Hydraulic Engineering, 146(6).
Panici D, de Almeida GAM (2018). Formation, Growth, and Failure of Debris Jams at Bridge Piers.
Water Resources Research,
54(9), 6226-6241.
Abstract:
Formation, Growth, and Failure of Debris Jams at Bridge Piers
The accumulation of large wood debris around bridge piers obstructs the flow, producing increased upstream water levels, large horizontal structural loadings, and flow field modifications that can considerably exacerbate scour. These effects have frequently been held responsible for the failure of a large number of bridges around the world, as well as for increased risk of flooding of adjacent areas. Yet little is currently known about the time evolution and processes responsible for the formation and growth of these debris piles. This paper is aimed at deciphering the whole life of debris accumulations through an exhaustive set of 570 experiments in which debris elements were individually introduced into a flume and accumulated at a pier model downstream. Our findings show that in all experiments, the growth of accumulations is halted at a critical stage, after which the jam is removed from the pier by the flow. This condition typically coincides with the time when the dimensions of the accumulations are maxima. The values of the accumulation maximum size display a clear dependence on flow characteristics and debris length distribution. On the other hand, other variables have shown much weaker effects on the geometry of the accumulations. For a given debris length, accumulations are wide, shallow, and long at low flow velocities but become narrower, deeper, and shorter with increasing velocities. A comparison of results of accumulations formed with debris of uniform and nonuniform size distributions has revealed that the former can be up to 2.5 times wider than the latter.
Abstract.
Chapters
Panici D (2020). Assessing bridges liable to debris accumulations from satellite imagery. In (Ed) River Flow 2020, CRC Press, 2314-2319.
Panici D, Kripakaran P (2020). Testing the efficiency of a woody debris retention structure for medium or small-sized rivers. In (Ed) River Flow 2020, CRC Press, 1639-1644.
Conferences
Alessandro S, Irene M, Ruby A, Roskilly K, Bennett G, Luo C (2023). Smart sensors to detect movements of cobbles and large woody debris dams. Insights from lab experiments. 25th EGU General Assembly. 23rd - 28th Apr 2023.
Panici D, Bennett GL (2022). Multi-phase Modelling of Landslide-flood Cascading Hazards: a Case-study from the 2013 Great Colorado Flood.
Abstract:
Multi-phase Modelling of Landslide-flood Cascading Hazards: a Case-study from the 2013 Great Colorado Flood
Abstract.
Panici D, de Almeida G (2022). The Influence of Pier Shape on the Accumulations of Large Wood Debris.
Abstract:
The Influence of Pier Shape on the Accumulations of Large Wood Debris
Abstract.
PANICI D, KRIPAKARAN P, DENTITH K (2019). ASSESSING DEBRIS-INDUCED SCOUR AT PIERS IN REAL-WORLD PRACTICE: a CASE STUDY. 38th IAHR World Congress.
PANICI D, DE ALMEIDA GAM (2019). THE IMPORTANCE OF DEBRIS SHAPE IN EXPERIMENTS ON WOODY DEBRIS ACCUMULATIONS AT BRIDGE PIERS. 38th IAHR World Congress.
Reports
Panici D, Kripakaran P, Dentith K (2019). Embedding techniques for assessing debris-induced scour within practice. Exeter, UK, University of Exeter.
Publications by year
In Press
Panici D (In Press). A theoretical analysis of the fluid-solid interactions governing the removal of woody debris jams from cylindrical bridge piers. Journal of Fluid Mechanics
Panici D, Kripakaran P (In Press). Assessing and mitigating risks to bridges from large wood using satellite imagery.
Proceedings of the ICE - Bridge EngineeringAbstract:
Assessing and mitigating risks to bridges from large wood using satellite imagery
The transport and accumulation of floating large wood (LW) debris at bridges can pose a major risk to their structural integrity. The impact forces arising from collisions of LW can cause significant damage to piers, and accumulations can constrict the flow and exacerbate scour at piers and abutments. Furthermore, LW accumulations increase afflux upstream of bridges, heightening flood risk for adjoining areas. Consequently, there is a need for a practical and rapid approach to identify bridges prone to LW-related hazards and to prevent the formation of LW accumulations. This paper proposes an approach based on satellite imagery to (i) quantify the risk of LW at a bridge structure and (ii) locate a LW-trapping system upstream of the identified vulnerable bridges to dramatically reduce risks of LW-related damage. This methodology is applied to major rivers in Devon (UK). 26 bridges were identified as at risk to LW with the majority prone to LW jams. Furthermore, satellite imagery was used to identify 12 locations for the potential installation of LW trapping systems for bridge protection. The results reported in this paper show that satellite imagery is a powerful tool for the rapid assessment and plan of mitigation measures for bridges at risk to LW.
Abstract.
Panici D (In Press). Characterising the importance of porosity of large woody debris accumulations at single bridge piers on localised scour. Water Resources Research
Panici D, Kripakaran P (In Press). Closure of “Trapping Large Wood Debris in Rivers: Experimental Study of Novel Debris Retention System”. Journal of Hydraulic Engineering
Panici D, Kripakaran P (In Press). TRAPPING LARGE WOOD DEBRIS IN RIVERS: EXPERIMENTAL STUDY ON a NOVEL DEBRIS RETENTION SYSTEM. Journal of Hydraulic Engineering
2023
Panici D, Kripakaran P (2023). Characterising the importance of porosity of large woody debris accumulations at single bridge piers on localised scour.
Alessandro S, Irene M, Ruby A, Roskilly K, Bennett G, Luo C (2023). Smart sensors to detect movements of cobbles and large woody debris dams. Insights from lab experiments. 25th EGU General Assembly. 23rd - 28th Apr 2023.
2022
Pregnolato M, Giordano PF, Panici D, Prendergast LJ, Pina Limongelli M (2022). A comparison of the UK and Italian national risk-based guidelines for assessing hydraulic actions on bridges.
STRUCTURE AND INFRASTRUCTURE ENGINEERING Author URL.
Egedusevic M, Bennett G, Roskilly K, Sgarabotto A, Manzella I, Raby A, Boulton SJ, Clark M, Curtis R, Panici D, et al (2022). Monitoring the stability of leaky dams and their influence on debris transport with innovative sensor technology on the SENSUM project.
Abstract:
Monitoring the stability of leaky dams and their influence on debris transport with innovative sensor technology on the SENSUM project
<p>Woody debris dams/leaky dams are an increasingly popular Natural Flood Management (NFM) measure in low order tributaries, with preliminary evidence suggesting that they are effective in attenuating flood peaks and reducing flood risk. However, the stability of these dams is not widely monitored, and thus there is a poor evidence base for best design practice with respect to the long-term integrity of such features. This is particularly pertinent given the threat posed to downstream infrastructure by woody debris carried in floodwaters after potentially catastrophic dam failure. There is also a lack of research into how effective dams of different designs are at holding back large wood and sediment transported by the flow and reducing the impact of flood debris on downstream infrastructure, including bridges, culverts etc. In the SENSUM project (Smart SENSing of landscapes Undergoing hazardous hydrogeomorphic Movement, https://sensum.ac.uk), we are developing and applying innovative sensor technology to assess the stability of different woody debris dam designs and build an evidence base to inform policy on this NFM practice locally and nationally. We also use these sensors to track woody debris and assess how effective dams are at trapping and retaining large wood debris and cobble-sized sediment. This paper addresses these questions at several field sites across the UK and in laboratory experiments to report quantitative data which evaluate the literal success/failure of NFM interventions and how these may impact the future design of such approaches.</p>
Abstract.
Panici D, Bennett GL (2022). Multi-phase Modelling of Landslide-flood Cascading Hazards: a Case-study from the 2013 Great Colorado Flood.
Abstract:
Multi-phase Modelling of Landslide-flood Cascading Hazards: a Case-study from the 2013 Great Colorado Flood
Abstract.
Panici D, de Almeida G (2022). The Influence of Pier Shape on the Accumulations of Large Wood Debris.
Abstract:
The Influence of Pier Shape on the Accumulations of Large Wood Debris
Abstract.
2021
Panici D (2021). An Experimental and Numerical Approach to Modeling Large Wood Displacement in Rivers.
Water Resources Research,
57(7).
Abstract:
An Experimental and Numerical Approach to Modeling Large Wood Displacement in Rivers
AbstractLarge wood (LW) is used for river restoration, aquatic habitat conservation, and flood control; however, it can pose a threat to human life and the built environment. The formation of LW jams, river management strategies, and design of mitigation measures crucially all depend on how the large wood is transported along a river. This paper experimentally analyses at laboratory scale the motion of natural sticks in a long stretch of a straight channel (16 m), when LW is released at different locations and with different flow conditions. Results show that instream large wood, following a transient motion shortly after being released at the water surface, tends to follow preferential patterns along the channel. Froude number and location of large wood input may provide an estimation of the LW location in downstream reaches. Several mechanisms of motion were observed, some of which were very common, including a frequent tendency to assume a tilted position with respect to the direction parallel to the flow. The experiments also suggest that theories on secondary cells responsible for channeling LW in preferential directions are incomplete. A new model, based on acceleration induced by hydrodynamic actions, has been established and proposed in this work, showing promising results and paving the way for the development of a comprehensive model for transport of large wood at the river surface in full‐scale applications.
Abstract.
Panici D (2021). An experimental and numerical approach to modeling large wood displacement in rivers.
2020
Ebrahimi M, Djordjević S, Panici D, Tabor G, Kripakaran P (2020). A method for evaluating local scour depth at bridge piers due to debris accumulation.
Proceedings of the Institution of Civil Engineers - Bridge Engineering,
173(2), 86-99.
Abstract:
A method for evaluating local scour depth at bridge piers due to debris accumulation
a novel method for evaluating the effect of debris accumulation on local scour depth at bridge piers is introduced. The concept of a ‘debris factor’ is proposed to replace the current effective and equivalent pier width approaches that have been shown to overestimate debris-induced scour in many instances. The concept enables a simpler, more direct and realistic estimation of the change in local scour depth due to debris since it accounts for debris length (streamwise), width (spanwise) and thickness (depth wise), along with the influence of debris elevation in the flow; that is, it is applicable for free-surface debris, submerged debris or debris resting on the stream bed. The concept works with all existing local scour equations alongside other factors that influence scour depth such as flow angle of attack and pier shape. The mathematical model underpinning the proposed concept was derived through multiple linear regression of experimental data obtained at Exeter University and elsewhere. The proposed method was found to improve accuracy by at least 24% and 5% in comparison with the effective and equivalent pier width approaches, respectively. More importantly, the method is robust, providing highly consistent results with significantly less uncertainty.
Abstract.
Panici D, Kripakaran P, Djordjevic S, Dentith K (2020). A practical method to assess risks from large wood debris accumulations at bridge piers. Science of the Total Environment
Panici D (2020). Assessing bridges liable to debris accumulations from satellite imagery. In (Ed) River Flow 2020, CRC Press, 2314-2319.
Panici D, de Almeida GAM (2020). Influence of Pier Geometry and Debris Characteristics on Wood Debris Accumulations at Bridge Piers. Journal of Hydraulic Engineering, 146(6).
Panici D (2020). TRAPPING LARGE WOOD DEBRIS IN RIVERS: EXPERIMENTAL STUDY ON a NOVEL DEBRIS RETENTION SYSTEM (dataset).
Panici D, Kripakaran P (2020). Testing the efficiency of a woody debris retention structure for medium or small-sized rivers. In (Ed) River Flow 2020, CRC Press, 1639-1644.
2019
PANICI D, KRIPAKARAN P, DENTITH K (2019). ASSESSING DEBRIS-INDUCED SCOUR AT PIERS IN REAL-WORLD PRACTICE: a CASE STUDY. 38th IAHR World Congress.
Panici D, Kripakaran P, Dentith K (2019). Embedding techniques for assessing debris-induced scour within practice. Exeter, UK, University of Exeter.
PANICI D, DE ALMEIDA GAM (2019). THE IMPORTANCE OF DEBRIS SHAPE IN EXPERIMENTS ON WOODY DEBRIS ACCUMULATIONS AT BRIDGE PIERS. 38th IAHR World Congress.
2018
Panici D, de Almeida GAM (2018). Formation, Growth, and Failure of Debris Jams at Bridge Piers.
Water Resources Research,
54(9), 6226-6241.
Abstract:
Formation, Growth, and Failure of Debris Jams at Bridge Piers
The accumulation of large wood debris around bridge piers obstructs the flow, producing increased upstream water levels, large horizontal structural loadings, and flow field modifications that can considerably exacerbate scour. These effects have frequently been held responsible for the failure of a large number of bridges around the world, as well as for increased risk of flooding of adjacent areas. Yet little is currently known about the time evolution and processes responsible for the formation and growth of these debris piles. This paper is aimed at deciphering the whole life of debris accumulations through an exhaustive set of 570 experiments in which debris elements were individually introduced into a flume and accumulated at a pier model downstream. Our findings show that in all experiments, the growth of accumulations is halted at a critical stage, after which the jam is removed from the pier by the flow. This condition typically coincides with the time when the dimensions of the accumulations are maxima. The values of the accumulation maximum size display a clear dependence on flow characteristics and debris length distribution. On the other hand, other variables have shown much weaker effects on the geometry of the accumulations. For a given debris length, accumulations are wide, shallow, and long at low flow velocities but become narrower, deeper, and shorter with increasing velocities. A comparison of results of accumulations formed with debris of uniform and nonuniform size distributions has revealed that the former can be up to 2.5 times wider than the latter.
Abstract.
