Fire detection, fuel model estimation and fire propagation estimation/visualization for the protection of Cultural Heritage

FIRESENSE (Fire Detection and Management through a Multi-Sensor Network for the Protection of Cultural Heritage Areas from the Risk of Fire and Extreme Weather Conditions) is a project co-funded by EU FP7 Environment that aims to develop a multi-sensor early warning system to remotely monitor areas of archaeological and cultural interest from the risk of fire and extreme weather conditions. It will combine different sensing technologies, i.e. wireless networks of temperature/humidity sensors, optical and infrared cameras, as well as local weather stations. Pilot deployments will be made in five cultural heritage sites in Greece, Turkey, Italy and Tunisia. Another goal is the estimation of the propagation direction and speed in order to help forest fire management. FIRESENSE will provide real-time information about the evolution of fire using wireless sensor network data and estimate the propagation of the fire based on the fuel model of the area and other important parameters such as wind speed, slope, and aspect of the ground surface. The fire propagation data are visualized on a user-friendly 3D-GIS environment. Some of the supported features are: a) Display of sensor locations and regions of interest in the cultural sites b) Interactive selection of some parameters (e.g. ignition point, humidity parameters) c) Automatic acquisition of weather data from onsite or nearby weather stations d) 2-D or 3-D visualization of fire propagation estimation output (ignition time and flame length). Commercial satellite images have reached a fairly high spatial resolution which allows more powerful textural analyses and more detailed description of soil surface. This improves the capacity to recognize and classify land uses, the amount and typology of vegetation and other potential sources of fuel for wildfires. It also reduced substantially the time and costs for updating vegetation and fuel distribution. Ground truth is also required especially for developing and testing of new image analysis algorithms. Measurements of the main fuel component are required and are usually destructive and costly, sometimes even unacceptable, especially if biodiversity or soil are threatened or in protected sites. Therefore, a sampling technique has been developed for single or groups of plants. Sub-volumes, which are characterized by the same type of fuel component and vegetation mix, are sampled over small known volumes. Volumetric mass densities are transformed into biomass and fuel components as mass per unit of surface. Very-High-resolution satellite images (QuickBird) are ortho-rectified with a detailed DTM of the study area and analyzed: recognition of lines of water flux convergence, pathways, usually unrecorded on official maps, vegetation patchiness, connectivity lines for fire to spread more easily, and connectivity lines for water fluxes during rainstorms will be among the results. Another approach that we use for vegetation classification is multi-band SVM classification approach. Each band characterizes/emphasizes a particular type of information such as textural, spatial, local and spectral information. The combination of these features improves significantly the accuracy of the results. We are currently investigating the registration between the ortho-rectified images and a ground truth map from the covered area in order to validate and improve the classification results. It is expected that the characterization of these areas and the accumulation of temporal series of vegetation/fuel distribution will serve not just for fire prevention and management but also for soil conservation and soil erosion control

The potential of permanent gullies in Europe as geomorphosites

Geotourism is a useful way to educate societies in the field of geomorphology and natural hazards. Geosites, including geomorphosites, represent the basis for the development of this type of tourism. This study describes twelve representative gully regions within nine European countries. The characteristics of 42 permanent gullies, gully systems and badland landscapes are presented and a geotouristic assessment of these gullies was made, based on scientific, educational, functional and touristic indicators. This assessment demonstrates a large difference between the selected gully sites, particularly with regard to functional and tourist values. The geotouristic potential of gullies is the highest in Italy and Spain and the lowest in Romania and Latvia. In some countries, permanent gullies are not regarded as geotouristic attractions at all, while in others they constitute a significant element of their tourism development strategy. Based on the analysis of scientific values of the gully sites, educational lessons to be learned were identified that are mainly related to i) gullies as a geological window, ii) present-day geomorphological processes, and iii) stages of historical gully erosion reflecting past human-environment interactions. These must be part of a broader strategy for the development of geotourism in gully regions. Gullies are potential geosites within existing or planned geoparks. Values of gullies for other forms of tourism (active, cultural, nature), should be also emphasized

Measuring, modelling and managing gully erosion at large scales: A state of the art

Soil erosion is generally recognized as the dominant process of land degradation. The formation and expansion of gullies is often a highly significant process of soil erosion. However, our ability to assess and simulate gully erosion and its impacts remains very limited. This is especially so at regional to continental scales. As a result, gullying is often overlooked in policies and land and catchment management strategies. Nevertheless, significant progress has been made over the past decades. Based on a review of >590 scientific articles and policy documents, we provide a state-of-the-art on our ability to monitor, model and manage gully erosion at regional to continental scales. In this review we discuss the relevance and need of assessing gully erosion at regional to continental scales (Section 1); current methods to monitor gully erosion as well as pitfalls and opportunities to apply them at larger scales (section 2); field-based gully erosion research conducted in Europe and European Russia (section 3); model approaches to simulate gully erosion and its contribution to catchment sediment yields at large scales (section 4); data products that can be used for such simulations (section 5); and currently existing policy tools and needs to address the problem of gully erosion (section 6). Section 7 formulates a series of recommendations for further research and policy development, based on this review. While several of these sections have a strong focus on Europe, most of our findings and recommendations are of global significance.info:eu-repo/semantics/publishedVersio

A review of topographic threshold conditions for gully head development in different environments

Gully head development represents a significant geomorphic process in a wide range of environments. Several studies investigated the critical topographic conditions, expressed by local slope gradient (s) and drainage area (A), controlling the development and position of gully heads in various landscapes. This review examines over 39 publications. After critically analysing the reported threshold data and after standardisation of the procedure to determine the critical topographic conditions for gully head development, i.e., sAb N k or s N kA−b some data sets were discarded because they were not compatible with the standard presentation of data as reported by the majority of studies. Hence, a detailed analysis was made of 63 reported s–A relationships for overland-flow induced gully-heads extracted from data sets collected in various parts of the world. A first examination of the behaviour of both the exponent b and the threshold coefficient k, which reflects the resistance of the site to gully head development, shows clear effects of land use on the value of k whereas the value of b does not seem to be affected. Further analyses are conducted of the recalculated threshold coefficients k, for two predefined constant values of the exponent b. The lowest k-valueswere observed for cropland followed by values for rangeland, pasture and forest. Effects of climate, rock fragment cover at the soil surface and water storage capacity of the gully catchment on k-valueswere also shown. Themost interesting result is that for a given and constant b-value, the threshold coefficient k can be predicted using soil and vegetation characteristics, based on the NRCS Runoff Curve Number values and on surface rock fragment cover. Furthermore, the underlying physical processes explaining the value of the exponent b were analysed. Finally, a physically-basedmodel,well anchored in the established theories, is proposed as a first step to predict gully head development in various landscapes and under changing environmental conditions. The results of this review clearly show that better and more reliable models can be built, including effects of land use, climate changes and natural disasters.status: publishe

Assessment of tillage erosion by mouldboard plough in Tuscany (Italy)

This study was designed to characterise the soil translocation effect induced by mouldboard ploughing with an implement traditionally used in the Tuscany region (Central Italy).We discuss the results of a set of field experiments performed to measure soil displacement along slopes of varying gradient in different directions and at several depths of tillage. Using the Soil Erosion by Tillage (SETi) model, soil translocation patterns for different tillage scenarios were analysed, with special attention paid to the effects of the direction and depth of tillage on the extent and spatial pattern of soil movement. The lateral slope gradient SP and tillage depth D were found to be the dominant controlling factors for total soil displacement. The effect of the slope gradient in a direction parallel to tillage ST was much less pronounced. These findings reveal the importance of the asymmetric nature of the soil movement produced by mouldboard ploughing and the predominant effect of the lateral displacement dP on the actual trajectory of soil motion. Results demonstrate that spatial patterns of soil redistribution due to mouldboard ploughing are highly variable and depend on the particular characteristics of the implement used. This dependence is so strong that maximum downslope soil translocation can occur during both, contour tillage or up–down tillage. For this particular mouldboard plough, maximum downslope soil transport took place at a tillage direction ca. 708 and not when tillage was conducted along the steepest slope direction (08). These findings highlight the potential of the combined approach applied. The physically based SETi model can be properly calibrated using a relatively limited dataset from field experiments. Once calibrating, the SETi model can then be used to generate synthetic tillage translocation relationships, which can predict the intensity and spatial pattern of soil translocation over a much wider range of tillage scenarios than the particular experimental conditions, in terms of topography complexity (slope gradients and morphology) and the direction and depth of tillage. These synthetic relationships are useful tools for evaluating strategies designed to reduce tillage erosion

A robust algorithm for estimating soil erodibility in different climates

The analysis of global soil erodibility data by Salvador Sanchis et al. (2008) showed that there is a significant climate effect on soil erodibility which allows for a split of the data into two subsets, one for prevailing cool conditions and another for prevailing warm conditions (defined using the Köppen climate classification). Despite the recognition of this new dichotomous variable, prediction of soil erodibility values remained very poor. This paper presents a new technique for dealing with such a variability by calculating probability density functions of soil erodibility K values when the user knows a set of textural parameters and the climatic classification of the site. Finally the user has the possibility to decide, on the basis of local knowledge, which K value to use. The procedure has been implemented in a freeware software named KUERY available for the scientific community. Finally, as an illustration, the methodology is applied to a catchment in south Italy.status: publishe

The Use of Stereoscopic Satellite Images to Map Rills and Ephemeral Gullies

Accurate mapping and measurement of erosion channels is necessary to accurately estimate the impact of channeled erosion in an area. Field surveys can provide optimal quantitative results, but they are only applicable to small areas. Recently, photogrammetric techniques have been applied to small format aerial photographs that were taken by UAVs. Few studies have applied photogrammetry for mapping and measuring single permanent gullies using very high resolution stereoscopic satellite images. We explore the use of such images to map rills and ephemeral gullies and to measure the length, width and depth of individual erosion channels to estimate the eroded volumes. The proposed methodology was applied to the Collazzone area of Central Italy. All of the channel characteristics were determined using GeoEye-1® panchromatic stereoscopic satellite images of the 48-km2 study area and a 3D floating cursor. We identified, mapped, and measured the lengths of 555 channel segments. The top width and depth could be measured in only a subset of the channel segments (the SMC subset). The SMC data were used to determine the coefficients of the power law relationship between the rill/gully volume and length (V = aLb) and the uncertainties due to the channel depth measurements and the cross-sectional shape. The field data of the rill and gully volumes were within the estimated uncertainty. We defined a decision rule to distinguish rills from gullies on the basis of the segment length and applied the corresponding power law relationship that was derived from the SMC subset to estimate the eroded volume of the entire dataset. The erosion values that were calculated at different scales (0.680 Mg∙ha−1 at the catchment scale, 28.4 Mg∙ha−1 on the parcels affected by erosion) are consistent with values found in the literature. Our results indicate that erosion at the catchment scale can be considered moderate, whereas the erosion at the field scale exceeds the tolerance limit, which is consistent with data that have been summarized and/or discussed by several authors

BIO_SOS Modelling Activities: Modelling Runoff-Sediment Connectivity. GI_Forum|GI_Forum 2013 – Creating the GISociety|

Pressures and threats to an ecosystem and its function need to be predicted and quantified: only knowing them, actions can be taken to avoid them. This is particularly true when the pressures are created by human actions and decisions. Part of these pressures causes changes in a) the water (and sediment) regime, b) the input of water and sediment into given parts of an ecosystem and c) water availability. These impacts can be estimated by means of a simple runoff-erosion model, easy to use and to understand and linked to a spatially distributed description of the landscape where the ecosystem to protect and conserve is located

Spatial variation of bed roughness in eroding rills and gullies

When overland flow concentrates rill and gully channels can be formed if a series of thresholds are exceeded. These thresholds are more or less explicitly linked to the erosion resistance of the topsoil. Moreover, flow velocity and channel width depend on total flow discharge. More recently also bed roughness in eroding channels has been attributed to the eroding effect of flow discharge while channel width was shown to be the result of the interplay between erosion resistance of the topsoil and flow discharge (see channel junction approach,Torri et al., 2006), which could be described by a modified Leopold and Maddock's relationship. The objective of this paper is to investigate the spatial variability of channel bed roughness in rills and gullies using an approach based on these findings. Field data confirm the various aspects reported so far. Hence these were used to develop a new equation allowing one to predict bed roughness in eroding rill and gully channels. Each of the new aspects introduced into the channel width–flow discharge equation by the channel junction approach is discussed and verified with new data. The validity of this approach is tested against channel data from Mars. Finally, an equation predicting bed roughness and based on stream power is developed and compared with measured rill and gully bed roughness successfully, confirming that 1) bed roughness, if generated by concentrated flow, increases with stream power; 2) channel width, local bed slope, topsoil cohesion at saturation, and grain size are all important factors controlling channel bed roughness; and 3) these variables as well as soil characteristics, all measurable in the field after a rill or gully forming event, are sufficient to determine channel bed roughness. Therefore one may expect that bed roughness of an eroded channel (and consequently hydraulic roughness or friction) will generally increase with bed gradient, erosion resistance of the soil and grain size, following a logic which is best expressed by the final equations described in this paper.status: publishe

BIO_SOS Modelling Activities: Modelling Runoff-Sediment Connectivity. GI_Forum|GI_Forum 2013 – Creating the GISociety|

Pressures and threats to an ecosystem and its function need to be predicted and quantified: only knowing them, actions can be taken to avoid them. This is particularly true when the pressures are created by human actions and decisions. Part of these pressures causes changes in a) the water (and sediment) regime, b) the input of water and sediment into given parts of an ecosystem and c) water availability. These impacts can be estimated by means of a simple runoff-erosion model, easy to use and to understand and linked to a spatially distributed description of the landscape where the ecosystem to protect and conserve is located