Planning bank stabilization and vegetated buffer (or filter) strips (VBS or VFS) works requires t... more Planning bank stabilization and vegetated buffer (or filter) strips (VBS or VFS) works requires the estimation of some hydrologic and hydraulic parameters. First of all it is important to consider the relationships among water levels of the river cross section and of the groundwater in different seasons and flood or river bed. From a hydrological point of view, having at disposal historical data series of discharge measurements in a given river cross section (direct measurements or re-constructed) it is possible to determine a "duration" curve of the daily discharges (discharge values which are exceeded for a given duration in days as a function of the duration) and an "increasing" curve of the maximum annual discharge (maximum annual peak discharge values as a function of the return time). For example it is possible to couple the two curves obtaining the non-dimensional (Q/Qm) variation with time (years) for 3 rivers in Central Italy.
A basin scale analysis of pollution caused by the use of chemical substances in agriculture in so... more A basin scale analysis of pollution caused by the use of chemical substances in agriculture in some basins of Central Italy is being carried out, through modelling and experimental research. The methodology is based on a distributed parameter model that allows consideration of climatic, geomorphologic, lithologic, pedologic, anthropic characteristics and the main dynamics of transport and transformation of substances which take place in the basin. The experimental investigation is led by the Istituto di Agronomia e Coltivazioni Erbacee of the University of Bologna in collaboration with the Dipartimento di Ingegneria Civile of the University of Florence as regards the modelling aspect and the extension at basin scale.
The recognized inefficiency of many irrigation systems, set up in developing countries in the pas... more The recognized inefficiency of many irrigation systems, set up in developing countries in the past years, forced the attention to be focused on the investigation of the causes of such a failure. The diagnostic analysis, an investigation process which aims at revealing problems, causes and effects related to the relevant actors involved in the system, has been applied to the Chambo irrigation system, located in an area of the Andes of Ecuador, 200 km south of Quito. Since the focal point of such a methodology is the user participation, through an information survey collected directly on the field, the «problems» were singled out, and were classified according tocause-effect relations and structured into a problem ,tree. This process allowed to defining ,the objectives and the proposals for solutions which were worked,out by considering transferability and sustainability by system users. Solutions to one of the main reason of interruption in the water supply service, slope landslides,...
... This amount is 6.41 times the food energy delivered by the system. By 1970 this ratio had inc... more ... This amount is 6.41 times the food energy delivered by the system. By 1970 this ratio had increased to approximately 7.4 (Hirst, 1973). The results of an analysis of where this primary energy was used in the food provision process in 1963 (Hirst, 1973) are given below: ...
This study provides the first insights of a methodology for estimating the additional cohesion ex... more This study provides the first insights of a methodology for estimating the additional cohesion exercised by vegetation roots in a hillslope landslide analysis within a coupled ecohydrological-stability model. The existing coupled system is able to simulate the spatial distribution and temporal dynamics of Factor of Safety (FS) as a function of soil moisture dynamics. The model takes into account the hydrological effects of vegetation which, through the root water uptaking, contributes in reducing the soil water content and, thus, in increasing the slope stability. The additional mechanical root cohesion is estimated in a Fiber Bundle Model (FBM) framework that allows for the evaluation of the root strength as a function of stress-strain relationships of populations of fibers. The use of such model requires the knowledge of the root architecture to evaluate the additional reinforcement from each root diameter class. In order to reproduce such characteristics, we adopted a branching topology model based on the Leonardo\u2019s rule that gives an estimation of the amount of root and the diameters distribution with depth at particular stage of plant life. The methodology has been tested in a simple synthetic hillslope with different configurations of vegetation types, i.e. tree and shrubs. The topological model has been calibrated using observed root area (AR) profiles of two considered vegetation types
This manuscript presents results of investigations into the root architecture and tensile strengt... more This manuscript presents results of investigations into the root architecture and tensile strength characteristics of Spanish Broom, and its potential benefits for stabilizing Mediterranean soils. The paper is well structured and shows that the authors have collected a fairly extensive data set, using appropriate field and laboratory techniques, which are described in very good detail in the paper. The analysis of the data, however, is less clear, as is the basis for the conclusions reached. With additional information regarding how the field data were used to obtain Cv and Fs values, and a greater discussion of these values in the text, comparing them to other literature values for root-reinforcement, this paper could be suitable for publication in this journal. Addi-
This study proposes a new methodology for estimating the additional shear strength (or cohesion) ... more This study proposes a new methodology for estimating the additional shear strength (or cohesion) exerted by vegetation roots on slope stability analysis within a coupled hydrological-stability model. The mechanical root cohesion is estimated within a Fiber Bundle Model framework that allows for the evaluation of the root strength as a function of stress-strain relationships of populations of fibers. The use of such model requires the knowledge of the root architecture. A branching topology model based on Leonardo's rule is developed, providing an estimation of the amount of roots and the distribution of diameters with depth. The proposed methodology has been implemented into an existing distributed hydrological-stability model able to simulate the dynamics of factor of safety as a function of soil moisture dynamics. The model also accounts for the hydrological effects of vegetation, which reduces soil water content via root water uptake, thus increasing the stability. The entire...
The preliminary validation of a new methodology for the analysis of the contamination caused by t... more The preliminary validation of a new methodology for the analysis of the contamination caused by the use of chemical substances in agriculture is presented. This methodology is based on distributed models that allow us to consider, at basin scale, geomorphological, pedological, meteorological, climatic, antropic characteristics and the main transport and transformation dynamics of chemical substances. Some studies about nonpoint pollution processes and distributed soil vulnerability have been already realized in some italian basins. The model validation has been obtained through the measured Atrazine herbicide losses from a small Georgia watershed. Besides a correct hydrological and sedimentological model balance, also the dissolved and adsorbed pesticide quantities calculated show a good agreement with the experimental data. Moreover an experimental plant, realized in a central Italy hilly zone for the monitoring of pesticides transport phenomena, at plot and basin scale, and for th...
In order to build up distributed models which require a proper evaluation of the different hydrol... more In order to build up distributed models which require a proper evaluation of the different hydrological, sedimentological and chemical variables, various algorithms developed and based on results obtained in former experiences are here presented. A digital model which divides the catchment with a square grid to obtain a set of cells, called rasters , is adopted and all quantities playing a role in the model are represented according to this methodology. They are geographic (elevation, watersheds, channels network, exposure, flowing index, etc.), geological and pedological (gravitational and capillary water storage, erodibility, etc.), climatic (rainfalls. temperature, humidity. etc.) and anthropic (land use, agricultural nonpoint pollution, etc.). A limited set of parameters that regulates the dynamics of water. sediments and pollutants are common fop the whole basin. Grid dimensions and balance time-step are not fixed in advance, but they depend on information accuracy.
Planning bank stabilization and vegetated buffer (or filter) strips (VBS or VFS) works requires t... more Planning bank stabilization and vegetated buffer (or filter) strips (VBS or VFS) works requires the estimation of some hydrologic and hydraulic parameters. First of all it is important to consider the relationships among water levels of the river cross section and of the groundwater in different seasons and flood or river bed. From a hydrological point of view, having at disposal historical data series of discharge measurements in a given river cross section (direct measurements or re-constructed) it is possible to determine a "duration" curve of the daily discharges (discharge values which are exceeded for a given duration in days as a function of the duration) and an "increasing" curve of the maximum annual discharge (maximum annual peak discharge values as a function of the return time). For example it is possible to couple the two curves obtaining the non-dimensional (Q/Qm) variation with time (years) for 3 rivers in Central Italy.
A basin scale analysis of pollution caused by the use of chemical substances in agriculture in so... more A basin scale analysis of pollution caused by the use of chemical substances in agriculture in some basins of Central Italy is being carried out, through modelling and experimental research. The methodology is based on a distributed parameter model that allows consideration of climatic, geomorphologic, lithologic, pedologic, anthropic characteristics and the main dynamics of transport and transformation of substances which take place in the basin. The experimental investigation is led by the Istituto di Agronomia e Coltivazioni Erbacee of the University of Bologna in collaboration with the Dipartimento di Ingegneria Civile of the University of Florence as regards the modelling aspect and the extension at basin scale.
The recognized inefficiency of many irrigation systems, set up in developing countries in the pas... more The recognized inefficiency of many irrigation systems, set up in developing countries in the past years, forced the attention to be focused on the investigation of the causes of such a failure. The diagnostic analysis, an investigation process which aims at revealing problems, causes and effects related to the relevant actors involved in the system, has been applied to the Chambo irrigation system, located in an area of the Andes of Ecuador, 200 km south of Quito. Since the focal point of such a methodology is the user participation, through an information survey collected directly on the field, the «problems» were singled out, and were classified according tocause-effect relations and structured into a problem ,tree. This process allowed to defining ,the objectives and the proposals for solutions which were worked,out by considering transferability and sustainability by system users. Solutions to one of the main reason of interruption in the water supply service, slope landslides,...
... This amount is 6.41 times the food energy delivered by the system. By 1970 this ratio had inc... more ... This amount is 6.41 times the food energy delivered by the system. By 1970 this ratio had increased to approximately 7.4 (Hirst, 1973). The results of an analysis of where this primary energy was used in the food provision process in 1963 (Hirst, 1973) are given below: ...
This study provides the first insights of a methodology for estimating the additional cohesion ex... more This study provides the first insights of a methodology for estimating the additional cohesion exercised by vegetation roots in a hillslope landslide analysis within a coupled ecohydrological-stability model. The existing coupled system is able to simulate the spatial distribution and temporal dynamics of Factor of Safety (FS) as a function of soil moisture dynamics. The model takes into account the hydrological effects of vegetation which, through the root water uptaking, contributes in reducing the soil water content and, thus, in increasing the slope stability. The additional mechanical root cohesion is estimated in a Fiber Bundle Model (FBM) framework that allows for the evaluation of the root strength as a function of stress-strain relationships of populations of fibers. The use of such model requires the knowledge of the root architecture to evaluate the additional reinforcement from each root diameter class. In order to reproduce such characteristics, we adopted a branching topology model based on the Leonardo\u2019s rule that gives an estimation of the amount of root and the diameters distribution with depth at particular stage of plant life. The methodology has been tested in a simple synthetic hillslope with different configurations of vegetation types, i.e. tree and shrubs. The topological model has been calibrated using observed root area (AR) profiles of two considered vegetation types
This manuscript presents results of investigations into the root architecture and tensile strengt... more This manuscript presents results of investigations into the root architecture and tensile strength characteristics of Spanish Broom, and its potential benefits for stabilizing Mediterranean soils. The paper is well structured and shows that the authors have collected a fairly extensive data set, using appropriate field and laboratory techniques, which are described in very good detail in the paper. The analysis of the data, however, is less clear, as is the basis for the conclusions reached. With additional information regarding how the field data were used to obtain Cv and Fs values, and a greater discussion of these values in the text, comparing them to other literature values for root-reinforcement, this paper could be suitable for publication in this journal. Addi-
This study proposes a new methodology for estimating the additional shear strength (or cohesion) ... more This study proposes a new methodology for estimating the additional shear strength (or cohesion) exerted by vegetation roots on slope stability analysis within a coupled hydrological-stability model. The mechanical root cohesion is estimated within a Fiber Bundle Model framework that allows for the evaluation of the root strength as a function of stress-strain relationships of populations of fibers. The use of such model requires the knowledge of the root architecture. A branching topology model based on Leonardo's rule is developed, providing an estimation of the amount of roots and the distribution of diameters with depth. The proposed methodology has been implemented into an existing distributed hydrological-stability model able to simulate the dynamics of factor of safety as a function of soil moisture dynamics. The model also accounts for the hydrological effects of vegetation, which reduces soil water content via root water uptake, thus increasing the stability. The entire...
The preliminary validation of a new methodology for the analysis of the contamination caused by t... more The preliminary validation of a new methodology for the analysis of the contamination caused by the use of chemical substances in agriculture is presented. This methodology is based on distributed models that allow us to consider, at basin scale, geomorphological, pedological, meteorological, climatic, antropic characteristics and the main transport and transformation dynamics of chemical substances. Some studies about nonpoint pollution processes and distributed soil vulnerability have been already realized in some italian basins. The model validation has been obtained through the measured Atrazine herbicide losses from a small Georgia watershed. Besides a correct hydrological and sedimentological model balance, also the dissolved and adsorbed pesticide quantities calculated show a good agreement with the experimental data. Moreover an experimental plant, realized in a central Italy hilly zone for the monitoring of pesticides transport phenomena, at plot and basin scale, and for th...
In order to build up distributed models which require a proper evaluation of the different hydrol... more In order to build up distributed models which require a proper evaluation of the different hydrological, sedimentological and chemical variables, various algorithms developed and based on results obtained in former experiences are here presented. A digital model which divides the catchment with a square grid to obtain a set of cells, called rasters , is adopted and all quantities playing a role in the model are represented according to this methodology. They are geographic (elevation, watersheds, channels network, exposure, flowing index, etc.), geological and pedological (gravitational and capillary water storage, erodibility, etc.), climatic (rainfalls. temperature, humidity. etc.) and anthropic (land use, agricultural nonpoint pollution, etc.). A limited set of parameters that regulates the dynamics of water. sediments and pollutants are common fop the whole basin. Grid dimensions and balance time-step are not fixed in advance, but they depend on information accuracy.
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