This study presents a methodology for improving the efficiency of Baptist and Stone and Shen models in predicting the global water flow resistance of a reclamation channel partly vegetated by rigid ...and emergent riparian plants. The results of the two resistance models are compared with the measurements collected during an experimental campaign conducted in a reclamation channel colonized by Common reed (Phragmites australis (Cav.) Trin. ex Steud.). Experimental vegetative Chézy’s flow resistance coefficients have been retrieved from the analysis of instantaneous flow velocity measurements, acquired by means of a downlooking 3-component acoustic Doppler velocimeter (ADV) located at the channel upstream cross section, and by water level measurements obtained through four piezometers distributed along the reclamation channel. The main morphometrical vegetation features (i.e., stem diameters and heights, and bed surface density) have been measured at six cross sections of the vegetated reclamation channel. Following the theoretical assumptions of the divided channel method (DCM), three sub-sections have been delineated in the reference cross section to represent the impact of the partial vegetation cover on the cross sectional variability of the flow field, as observed with the ADV measurements. The global vegetative Chézy’s flow resistance coefficients have been then computed by combining each resistance model with four different composite cross section methods, respectively suggested by Colebatch, Horton, Pavlovskii, and Yen. The comparative analysis between the modeled and the experimental vegetative Chézy’s coefficients has been performed by computing the relative prediction error (εr, expressed in %) under two flow rate regimes. Stone and Shen model combined with the Horton composite cross section method provides vegetative Chézy’s coefficients with the lowest εr.
Flood hazard mitigation in urban areas crossed by vegetated flows can be achieved through two distinct approaches, based on structural and eco-friendly solutions, referred to as grey and green–blue ...engineering scenarios, respectively; this one is often based on best management practices (BMP) and low-impact developments (LID). In this study, the hydraulic efficiency of two green–blue scenarios in reducing flood hazards of an urban area crossed by a vegetated river located in Central Tuscany (Italy), named Morra Creek, were evaluated for a return period of 200 years, by analyzing the flooding outcomes of 1D and 2D unsteady hydraulic simulations. In the first scenario, the impact of a diffuse effect of flood peak reduction along Morra Creek was assessed by considering an overall real-scale growth of common reed beds. In the second scenario, riverine vegetation along Morra Creek was preserved, while flood hazard was mitigated using a single vegetated flood control area. This study demonstrates well the benefits of employing green–blue solutions for reducing flood hazards in vegetated rivers intersecting agro-forestry and urban areas while preserving their riverine ecosystems. It emerged that the first scenario is a valuable alternative to the more impacting second scenario, given the presence of flood control areas.
Italian dry-stone wall terracing represents one of the most iconic features of agricultural landscapes across Europe, with sites listed among UNESCO World Heritage Sites and FAO Globally Important ...Agricultural Heritage Systems (GIAHS). The analysis of microclimate modifications induced by alterations of hillslope and by dry-stone walls is of particular interest for the valuation of benefits and drawbacks of terraces cultivation, a global land management technique. The aim of this paper is to perform a thermal characterization of a dry-stone wall terraced vineyard in the Chianti area (Tuscany, Italy), to detect possible microclimate dynamics induced by dry-stone terracing. The aerial surveys were carried out by using two sensors, in the Visible (VIS) and Thermal InfraRed (TIR) spectral range, mounted on Unmanned Aerial Vehicles (UAVs), with two different flights. Our results reveal that, in the morning, vineyard rows close to dry-stone walls have statistically lower temperatures with respect to the external ones. In the afternoon, due to solar insulation, temperatures raised to the same value for each row. The results of this early study, jointly with the latest developments in UAV and sensor technologies, justify and encourage further analyses on local climatic modifications in terraced landscapes.
The global agricultural sector needs to implement good soil management practices, in particular to prevent erosion and to improve water-retention capacity. The introduction of tillage techniques ...along particular theoretical lines, called keylines, can make a significant contribution to improving the management of the soil and agricultural crops. The keyline system has been around for less than 100 years. With this preliminary work, we performed a comparative analysis of two small river basins (less than 100 ha) before and after keyline application, based on GIS computational models (TWI and SIMWE). The calculation models were elaborated starting from a DTM with 2 m resolution, obtained from a LIDAR survey. The comparative analysis, in qualitative terms, showed a positive effect of the keylines, both in terms of erodibility and infiltration of runoff water. The use of GIS models to verify the effectiveness in the planning phase can constitute a decision support system that guides agronomists, technicians, and farmers.
The forestry sector in Italy and throughout Europe is going through a critical period due to ongoing natural and anthropological processes, such as climate change and the abandonment of rural areas. ...These processes lead to a constant fragmentation of properties in small forest parcels, with direct impacts on management capacity. In this framework, new sustainable forest management methods are being tested and are shown to be good practices to oppose the decline of forest ecosystems. Their innovative aspects concern the introduction of a form of shared and circular economy, where management is built on the process, rather than on the product. Their technical activities are based on precision forestry systems and digitalization. The new approach takes into consideration the fact that the woods are an asset available to the whole community, in terms of benefits and protection. Forest Sharing® is an example of the application of shared forest management systems, due to which the owner user benefits from several services and opportunities, such as the advanced monitoring platform and the access to investment funds. After eighteen months of activity, the first results of the application of the new management systems can already be seen. Many aspects need further development, such as case studies concerning the enhancement due to forest certification and new recreational activities. Shared forest management systems have the potential to increase the level of knowledge and awareness of citizens about environmental and territorial issues.
During 25 October 2011, an extremely intense rainfall event occurred in Eastern Liguria and Northern Tuscany. Severe damages were registered in the Monterosso and Vernazza basins, located in the ...famous area of Cinque Terre, which have been affected by hundreds of landslides, mud flows, and erosions. The main feature of the Cinque Terre landscape is the presence of terraced cultivations on steep slopes facing the sea. The area represents a remarkable cultural landscape, is a National Park, and is included in the World Heritage List of the UNESCO. This work aims to analyze the effect of abandoned terraced land on hydrogeological risks and in landslide prevention, by comparing what happened in Cinque Terre to other experiences presented in scientific literature. The cessation of maintenance of dry stone terraces due to the crisis of traditional agriculture was identified as the main cause of failure during the heavy rainfall event. However, we found some contrasting and, in some cases, unexpected results in the literature regarding the effects of the vegetation that develops on abandoned terraces. This paper compares different results in order to better understand what the future of terraced landscapes is and which are the best management strategies for such complex and fragile territories. In particular, where they represent a cultural heritage and a resource for the rural economy.
•Flow-vegetation interactions were examined at the real scale in a drainage channel.•Flow resistance and turbulence were analysed for three vegetation scenarios.•Manning’s n resulted higher than ...expected due to dead remnant material at the bottom.
Drainage channels are a widespread component of agricultural and urbanized lowland landscapes. Management of instream and riparian vegetation along drainage channels must be planned by reconciling the need to ensure channel hydraulic efficiency with the need to preserve the riparian habitat. The present paper reports the experimental results of a study conducted on a drainage channel colonized by Phragmites australis in undisturbed natural conditions. The impacts of common reed on flow resistance, flow velocity distribution and turbulence parameters were examined with different discharges under three different scenarios of channel vegetation, which were obtained by means of machineries traditionally used in land reclamation areas. Removing either totally or partially the channel vegetation had great effects on streamwise velocity distribution and turbulence patterns, with small differences in global flow resistance. The experimental results suggest that clearing the channel vegetation just in the center of the cross section can improve the channel conveyance to values close to those obtained with the total removal of the vegetation, while maintaining relatively high levels of turbulent intensities.
•Specific streamflow in Dolomitic nested catchments decreases with increasing spatial scales.•Snowmelt significantly controls streamflow response in the catchment with the highest ...elevations.•Analogous factors explain most of the variability of streamflow response at the different scales.•The first-order catchment was not always representative for the larger catchments.
Understanding how catchment streamflow response varies in time and at different spatial scales is critical to assess runoff production and water availability in mountain areas. Very little work on comparing runoff generation processes in catchments of increasing size has been done in Dolomitic areas. In this research, we adopted a nested catchment (0.14–109 km2) approach to i) assess whether and how streamflow response at the seasonal and the rainfall-runoff event time scale varies with increasing spatial scale, and ii) identify the main factors controlling the temporal variability of streamflow response in three mountain catchments in the Italian Dolomites. We used precipitation and streamflow data from June to September of 13 consecutive years (2005–2017) available for all three catchments, and computed runoff coefficients, stormflow volumes, streamflow peaks and lag times between the rainfall centroid and the streamflow peak for 203 rainfall-runoff events occurred during the study period. Results show that, overall, specific streamflow and runoff coefficients decreased with the increasing spatial scale. However, this pattern was disrupted at the end of spring-beginning of summer due to the relevant snowmelt contribution to streamflow in the intermediate catchment characterized by the largest fraction of high-elevation areas, where deep snowpack accumulated during the winter. The probability distribution of runoff coefficients was very well represented by a Beta-distribution for all three catchments, suggesting that analogous factors controlled the variability of runoff coefficients. This was confirmed by multiple regression analysis that revealed that event rainfall amount, storm duration and 3–12 days antecedent precipitation (assumed as a proxy for antecedent wetness conditions) explained up to 0.81 of the variability of streamflow response, with a minor role of rainfall intensity. Further research is needed to assess whether detailed measurements of hydrological variables collected at the small catchment scale (<1 km2) could be deemed as representative for the hydrological response of larger catchments.
Background: The way in which to prevent recurrent venous thromboembolism (VTE) is an unmet clinical need in cancer patients. International guidelines only provide conditional recommendations and do ...not specify which anticoagulant and dose should be used. In the last 2 years, we have been using low-dose rivaroxaban to prevent VTE recurrences in cancer patients. The results of this real-life experience are presented in this study. Methods: All patients had cancer and had previously completed a cycle of at least six months of full-dose anticoagulation for the treatment of a VTE index event, before receiving a prescription of low-dose rivaroxaban (10 mg once daily) for secondary prevention of VTE. Effectiveness and safety of this therapeutic regimen were evaluated in terms of VTE recurrences, major bleedings (MB), and clinically relevant non-major bleedings (CRNMB). Results: The analysis included 106 cancer patients. Their median age was 60 years (IQR 50–69). Metastatic cancer was present in 87 patients (82.1%). Six patients (5.7%) had brain metastases. Over a median follow-up time of 333 days (IQR 156–484), the incidence of VTE recurrences was 3.8% (95%CI 1.0–9.4), with a recurrence rate of 4.0 per 100 person-years (95%CI 1.1–10.2). We observed no MB (0.0%) and three CRNMB (2.8%) (95%CI 0.6–8.1). Conclusions: Low-dose rivaroxaban is potentially effective and safe in cancer patients that require prevention of recurrent VTE. Large-scale studies are needed to confirm these findings.
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