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The general aim of this work was to define a methodology for setting the environmental flows (E-Flows) in a temporary river with limited data availability through a case study. In the literature, there are many methods to set up an E-Flow, however, the issue is still an emerging discipline in non-perennial rivers due to the lack of specific guidelines at the European and national level and the limited availability of data (i.e., hydrological/biological).The study area is the Locone river basin (219 km2) located in southern Italy. The climate is typically Mediterranean. The flow regime shows a pattern of low flow and zero flow in summer. The Locone is classified by the River Basin Authority as a temporary river. Upstream of the dam, streamflow was measured from 1971 to 1983. The main land use is winter wheat (64% of the total area), followed by broad-leaved woods (6.6%) and broad beans (5.4%). The main hydrological pressure in the basin is represented by the Locone dam. It was built in 1986 for agricultural purposes (approximately 5,000 hectares are irrigated) and for a hydroelectric power station (1,693,000 kWh / year).To compensate for the lack of hydrological and ecological data, which characterizes these types of rivers, the open-source Soil and Water Assessment Tool Plus (SWAT +) model was applied. SWAT + is a completely revised version of the SWAT model, which is a physical scale and watershed model, which operates on a daily time step (Arnold et al., 1998). The model was calibrated (NSE = 0.720; Pbias = -11.514 and R2 = 0.84) and validated (NSE = 0.42; R2 = 0.45; Pbias = -12.5). The flow regime has been characterized under un-impacted conditions over a long period (1971-2020) using hydrological alteration indicators (IHAs) based on modeled daily flows. The E-Flow was set by fixing the variability range of each IHA within the interquartile (25th-75th percentile) by applying the Range of Variability Approach. For the Locone reservoir, the mean monthly flow of water releases, the magnitude, and duration of high and low flows, as well as the timing and frequency of floods and drought conditions were defined.This work made it possible to test the SWAT+ model in a Mediterranean environment, confirming its potential. The applied method represents a first useful evaluation analysis that should be revised following ecological data monitoring actions to corroborate the eco-hydrological relationships.

In the Mediterranean Region basins are characterized by a specific hydrological regime that generally includes periods of absence of flow and flash flood events. Lithological and geological features are factors that greatly affect the flow regime. In this work, the Soil and Water Assessment Tool (SWAT) model was applied to simulate the Canale d'Aiedda (Apulia, Italy) flow regime, a Mediterranean temporary karst river basin with limited data availability. Different basin delineations and model parameterizations were adopted that include: (i) cut-off of karst areas in GIS (Configuration A); (ii) setting up the basin including the karst areas (Configuration B) and (iii) parameterizing, in the calibration process, the Crack Flow function in the karst sub-basins (Configuration C). The model performed satisfactorily for daily streamflow for configurations B and C and good for A. A better simulated large floods. C was the best solution for monthly flow from May to July. Regarding the water balance, C showed higher surface runoff values and lower total water yield values than A and B. The Crack flow function proved to be a valid option to improve the simulation of hydrological processes in karst areas. Several factors, such as the final aim of the study, data availability, and basin characteristics should be considered in selecting the best model configuration.

The Environmental Flow regime (E-Flows) was defined as the flow regime necessary to support river ecosystems, which in turn support crops, the economy, sustainable livelihoods, and human well-being. Although a large number of methods for setting an E-Flow regime have been developed, E-Flows science is still an emerging discipline in non-perennial rivers because of the lack of specific guidelines at the European and national level and the limited data availability (i.e., hydrological/biological). The aim of the present work was to define a methodology for setting an E-Flow regime in a region with limited data availability. The proposed approach was tested in the Locone basin (S Italy). A long time series (1971 to 2020) of daily streamflow in un-impacted conditions were simulated by using the SWAT+ model, a new release of the Soil and Water Assessment Tool. The flow regime was characterized in un-impacted conditions by means of the Indicators of Hydrological Alterations (IHAs) based on modeled daily streamflow. The E-Flow regime was defined by adopting the Range of Variability Approach and assuming the interquartile range (25th - 75th percentile) as an acceptable range of variation of each IHA. For the Locone reservoir, the monthly water release pattern, magnitude, and duration of high and low flow were defined as well as the timing and frequency of floods, and dry conditions.

The evaluation of water shortages and pollution levels is crucial for watershed management and sustainable development. This paper proposes a water footprint (WF) sustainability assessment approach to analyse water security in a river basin under human pressures. The methodology involves a comprehensive assessment of the current water security at different spatial and temporal levels, and identifies suitable response formulations to achieve sustainability. Field surveys and measurements (streamflow, water quality) were carried out, and the Soil and Water Assessment Tool model was used for assessing water balance components and water quality. The study was carried out in the Canale d’Aiedda river basin (Taranto, Italy), which is part of the ‘area of environmental crisis’ of Taranto, which requires remediation of surface water, groundwater, soil and subsoil. Considering all the anthropogenic activities in the basin, including agriculture and the treated effluent disposed of via wastewater treatment plants (WWTPs), the average WF was 213.9 Mm3 y-1, of which 37.2%, 9.2% and 53.6% comprised respectively for WFgreen, WFblue and WFgrey. The WF sustainability assessment revealed that pollution was the main factor affecting surface water security. In particular, point sources contributed with 90% to the total WFgrey, and lower pollutant thresholds should be fixed for effluent from WWTPs in order to increase water quality of the receiving water body. In addition, for assuring water security the extension of the natural areas should be increased to support biodiversity in the river basin and soil management strategies should be improved to allow more water to be retained in the soil and to reduce nutrients in surface runoff. This study demonstrates that the WF sustainability assessment is a feasible approach for integrated water resources management, as well as offering a much broader perspective on how water security can be achieved in a Mediterranean basin affected by multiple anthropogenic stressors.

The excessive use of pesticides in agriculture poses a threat to water and environmental quality. Under Horizon Europe, considering the priorities of the European Green Deal (EGD), research activities, technological innovation, and investments are needed to contribute to reducing the use of pesticides, fertilizers, and antimicrobials. In this scenario, there is a need to carry out studies on the short and long-term effects of the use of pesticides in the agro-environment and on the effect of mitigation measures. For this purpose, hydrological models are useful tools for the simulation of the fate and transport of pesticides.Through a critical review, this study aims to: (i) update the status of the use of the hydrological models to simulate pesticides coming from diffuse pollution, (ii) Analyze the spatial and temporal scale of the model applications, (iii) Investigate possible relationships between models and specific pesticides. The ISI papers were selected based on six keywords were used on Scopus: “pesticides, model, watershed, hydrology, water quality, diffuse pollutant”. After removing articles, not in English and articles not related to modeling applications, 37 papers were found and analyzed by constituting a database containing information about the study areas, the pesticides, the model, and the methodology adopted (I.e. warm-up, calibration, and/or validation). Pesticides were classified into three categories: herbicides, fungicides, and insecticides.Results showed that most of the study areas were localized in Europe (55.5%) followed by North America (22.3%), Asia (13.9%), and South America (8.3%). Soil and Water Assessment Tool was the most commonly used model with a percentage of 45.95%. Regarding the substances investigated, herbicides were the most modeled (71.4%) followed by insecticides (18.2%) and fungicides (10.4%). In particular, among the most commonly modeled herbicides were atrazine, metolachlor, isoproturon, glyphosate, and acetochlor. Among the insecticides, chlorpyrifos and metaldehyde were the substances most frequently modeled. Finally, chlorothalonil and tebuconazole were the most investigated fungicides.This work will be useful to create an updated guideline to facilitate the water and the landscape managers in selecting a specific hydrological model to assess the transport and fates of pesticides and to simulate the effect of potential mitigation practices.

The present paper contributes to bridging the gaps in modelling post-fire impact and mitigation measures on soil erosion. The specific aims were to predict the effects of forest fires and post-fire mitigation measures on runoff and specific sediment yield (SSY) in a river basin (Celone, S-E Italy). The Soil and Water Assessment Tool model, calibrated with field observations, was used to evaluate runoff and SSY for the current land use (baseline) and six post-fire scenarios. From 1990 to 2011, at the basin scale, the average annual SSY was 5.60 t ha- 1yr-1 (SD = 3.47 t ha-1yr-1). 20% of the total drainage area showed a critical value of SSY (>10 t ha-1 yr-1). The effects of different fire-severity levels were predicted for one year after the fire, acting on a limited area (2.3% of the total basin area). At the basin scale, the post-fire effect on surface runoff was negligible for all scenarios (< 0.4%), and the impact on SSY increased from 5.86 t ha-1 yr-1 up to 12.05 t ha-1 yr-1. At the subbasin scale, the post-fire logging scenario showed the highest increase of soil loss (SSY increased from 9.48 t ha-1 yr-1 to 57.40 t ha-1 yr-1). Post-fire mitigation treatments like straw mulching and erosion barriers effectively reduced soil erosion in high- and moderate-severity fires (19.12 t ha-1yr-1 and 20.93 t ha-1 yr-1, respectively). At the hydrological response unit level, the SSY estimated for the forest in the baseline ranged from 1.18 t ha- 1yr-1 to 2.04 t ha-1 yr-1. SSY increased more than one order of magnitude for the high-severity fire scenarios and ranged from 4.33 to 6.74 t ha-1 yr-1 in the very low-severity fire scenario, underlining the scale effect from the HRU to the basin scale.

To gain a better understanding of the global application of soil erosion prediction models, we comprehensively reviewed relevant peer-reviewed research literature on soil-erosion modelling 1994-2017. Our aim was to identify (i) processes and models most frequently addressed in the literature, (ii) regions within which models are primarily applied, (iii) what regions remain unaddressed and why, and (iv) how frequently studies are conducted to validate/evaluate model outcomes relative to measured data. To perform this task, we merged the knowledge of a group of 66 soil-erosion scientists from 67 research institutions and 25 countries. The resulting database ‘Global Applications of Soil Erosion Modelling Tracker (GASEMT)’ includes 3,030 individual modelling records from 126 counties encompassing all continents (except Antarctica). Out of 8,471 articles identified as potentially relevant, we reviewed 1,697 articles and transferred relevant information from each into the database. For each record reported in the GASEMT database, 42 attributes were evaluated. The GASEMT database provides insights into the state-of-the-art of soil- erosion models and model applications worldwide. The database is also intended to support the upcoming country-based United Nations global soil-erosion assessment. This database may help inform soil erosion research priorities in that it builds a foundation for future targeted in-depth analyses. GASEMT is an open-source database that anyone can use to develop research, rectify errors, and expand.

This study aims to detect the variability of riparian vegetation by means of in-situ measurements of the Leaf Area Index (LAI) and its retrieval from Landsat 8 satellite images in a Mediterranean stream (‘Cammarota’, Puglia region, Southern Italy) characterized by the presence of intact and destroyed check dams. Fifty-three transects were measured using a Plant Canopy Analyzer and a broad range of LAI values (0.26–5.71) was observed. Lower values were found in Cammarota reaches with damaged or destroyed check dams that led to active erosive processes, whereas higher LAI values were detected in the reaches with greater geomorphological stability. These results were confirmed by the analysis of a nearby stream (‘Vallone della Madonna’) with intact check dams and sound riparian vegetation which produced a higher range (4.08–5.93) of LAI values. The LAI values of riparian vegetation in both streams were compared with those found in more homogeneous types of vegetation (wheat field and deciduous forest) in the surrounding areas, which were used as control plots. Landsat 8 satellite images relating to the same period of field activity were also analyzed, and the performance of three equations for deriving LAI values from the corrected Normalized Difference Vegetation Index (NDVI) was evaluated. The Lambert-Beer equation gave the best statistical performance for predicting LAI within the reaches of the Cammarota stream with a denser vegetation, as well as in the Vallone della Madonna stream and deciduous forest. The significant variability of the observed LAI values in the Cammarota reach subject to initial erosive processes, was not detected by any of the equations applied.

Most of the basins in the Mediterranean Region are characterized by a large spatial gradient in rainfall and temperature and heterogeneity in lithology, soil, and land use. Such environmental factors determine a specific hydrological regime of the river systems that generally includes periods of absence of flow and flash flood events.In the past decades, several countries in South Europe did not invest resources for the monitoring of the intermittent river systems. Currently, several basins have limited time series of streamflow and water quality data. In addition, it is not rare the case of climate stations not well distributed in the basin as well as the presence of several gaps in the time series.The lithology and geological features are among the main factors affecting the flow regime, playing a crucial role in groundwater and surface-water interaction and water exchange for which the flow may appear and disappear along with the river network. In such a complex environment, the hydrological and water quality model set up and run may be challenging.Through a case study, this work aims to face some challenges and to define problem-solving in simulating hydrology in Mediterranean basins. The area is characterized by (i) heterogeneity in lithology with karst areas, (ii) limited flow data availability for calibrating the model, (iii) flow intermittence in the river network. The Soil and Water Assessment Tool (SWAT) was applied to the Canale D’aiedda (Puglia, Italy), a temporary karst river basin under the Mediterranean climate and with limited data availability. Different solutions were tested to simulate the hydrological processes in the karstic areas including both GIS elaborations and model parameters settings and modifications. Among the main parameters, infiltration and transmission losses and soil hydraulic parameters resulted in the most relevant in simulating hydrology in the karst areas. To calibrate the model, a split-in-space procedure was adopted to overcome the limited streamflow measurement availability. Finally, a zero-flow threshold was introduced to predict the number of zero-flow days in the intermittent river reaches, simulating accurately the flow intermittence and the extreme low flow.The results show that by using specific strategies in setting-up and calibrating the model, the SWAT model is able to simulate daily streamflow with acceptable performances in complex river basins.

16 Pags.- 12 Figs.- 8 Tabls., Soil erosion can present a major threat to agriculture due to loss of soil, nutrients, and organic carbon. Therefore, soil erosion modelling is one of the steps used to plan suitable soil protection measures and detect erosion hotspots. A bibliometric analysis of this topic can reveal research patterns and soil erosion modelling characteristics that can help identify steps needed to enhance the research conducted in this field. Therefore, a detailed bibliometric analysis, including investigation of collaboration networks and citation patterns, should be conducted. The updated version of the Global Applications of Soil Erosion Modelling Tracker (GASEMT) database contains information about citation characteristics and publication type. Here, we investigated the impact of the number of authors, the publication type and the selected journal on the number of citations. Generalized boosted regression tree (BRT) modelling was used to evaluate the most relevant variables related to soil erosion modelling. Additionally, bibliometric networks were analysed and visualized. This study revealed that the selection of the soil erosion model has the largest impact on the number of publication citations, followed by the modelling scale and the publication's CiteScore. Some of the other GASEMT database attributes such as model calibration and validation have negligible influence on the number of citations according to the BRT model. Although it is true that studies that conduct calibration, on average, received around 30% more citations, than studies where calibration was not performed. Moreover, the bibliographic coupling and citation networks show a clear continental pattern, although the co-authorship network does not show the same characteristics. Therefore, soil erosion modellers should conduct even more comprehensive review of past studies and focus not just on the research conducted in the same country or continent. Moreover, when evaluating soil erosion models, an additional focus should be given to field measurements, model calibration, performance assessment and uncertainty of modelling results. The results of this study indicate that these GASEMT database attributes had smaller impact on the number of citations, according to the BRT model, than anticipated, which could suggest that these attributes should be given additional attention by the soil erosion modelling community. This study provides a kind of bibliographic benchmark for soil erosion modelling research papers as modellers can estimate the influence of their paper., Nejc Bezak and Matjaž Mikoš would like to acknowledge the support of the Slovenian Research Agency through grant P2-0180. Diana Vieira is funded by national funds (OE), through FCT – Fundação para a Ciência e a Tecnologia, I.P., in the scope of the framework contract foreseen - DL57/2016 (CDL-CTTRI-97-ARH/2018 - REF.191-97-ARH/2018), and acknowledges CESAM financial support of through (UIDP/50017/2020+UIDB/50017/2020). Jae E. Yang and Pasquale Borrelli are funded by the EcoSSSoil Project, Korea Environmental Industry & Technology Institute (KEITI), Korea (Grant No. 2019002820004). Walter Chen is funded by the Ministry of Science and Technology (Taiwan) Research Project (Grant Number MOST 109-2121-M-027-001).

40 Pags.- 10 Figs.- 2 Tabls.- Suppl. Informat. The definitive version is available at: https://www.sciencedirect.com/science/journal/00489697, To gain a better understanding of the global application of soil erosion prediction models, we comprehensively reviewed relevant peer-reviewed research literature on soil-erosion modelling published between 1994 and 2017. We aimed to identify (i) the processes and models most frequently addressed in the literature, (ii) the regions within which models are primarily applied, (iii) the regions which remain unaddressed and why, and (iv) how frequently studies are conducted to validate/evaluate model outcomes relative to measured data. To perform this task, we combined the collective knowledge of 67 soil-erosion scientists from 25 countries. The resulting database, named ‘Global Applications of Soil Erosion Modelling Tracker (GASEMT)’, includes 3030 individual modelling records from 126 countries, encompassing all continents (except Antarctica). Out of the 8471 articles identified as potentially relevant, we reviewed 1697 appropriate articles and systematically evaluated and transferred 42 relevant attributes into the database. This GASEMT database provides comprehensive insights into the state-of-the-art of soil- erosion models and model applications worldwide. This database intends to support the upcoming country-based United Nations global soil-erosion assessment in addition to helping to inform soil erosion research priorities by building a foundation for future targeted, in-depth analyses. GASEMT is an open-source database available to the entire user-community to develop research, rectify errors, and make future expansions., Jae E. Yang and Pasquale Borrelli are funded by the EcoSSSoil Project, Korea Environmental Industry & Technology Institute (KEITI), Korea (Grant No. 2019002820004). Diana Vieira is funded by national funds (OE), through FCT – Fundação para a Ciência e a Tecnologia, I.P., in the scope of the framework contract foreseen - DL57/2016 (CDL-CTTRI-97-ARH/2018 - REF.191-97-ARH/2018), and acknowledges CESAM financial support of through (UIDP/50017/2020+UIDB/50017/2020). Walter Chen is funded by the Ministry of Science and Technology (Taiwan) Research Project (Grant Number MOST 109-2121-M-027-001). Nejc Bezak and Matjaž Mikoš would like to acknowledge the support of the Slovenian Research Agency through grant P2-0180.

The study of suspended sediment transport requires continuous measurement of water discharge to better understand the sediment dynamics. Furthermore, a groundwater monitoring network can support the stream discharge measures, as it reveals how the interactions between surface water and groundwater may affect runoff and consequently sediment transport during flood events. An experimental site for the continuous monitoring of water discharge, suspended sediment transport and groundwater levels was set up in the Carapellotto basin (27.17 km2), which is located in Apulia, Southern Italy. Seven flood events that occurred in the operation timespan were covered with a full record of both water discharge and sediment concentration. Some monitoring problems, largely due to the clogging of the float by mud, suggested to improve the experimental set up. The results show high values of suspended sediments concentration which indicate the sub-basin&rsquo, s key role in the sediment delivery to the whole river system, while counter-clockwise hysteresis loops are the most frequent due to the basin characteristics. The effects of the interaction between surface water and groundwater are related not only to the flood magnitude but also to the hydrogeological features in the hyporheic zone.

In intermittent rivers and ephemeral streams (IRES), the hydrological regime is the primary driving force controlling the sediment transfer from the upland to the lowland catchment compartment, ergo the river geomorphology. The general objective of this study is to investigate the processes and the relationships between flow regime and suspended sediment (SS) transport in two IRESs with a different degree of intermittency, the Búger River (Spain) and the Carapelle River (Italy). The specific objectives are to (i) identify the drivers of SS transport, (ii) analyse and quantify the temporal variability of the SS transport in response to the hydrological regime. High-resolution data of streamflow and SS concentration (SSC) were used in this analysis and a set of hydrological indicators were computed to characterize and classify the flow regime.In the Búger River, the high degree of intermittency and the low runoff coefficient were mainly due to the presence of carbonate lithology in headwaters and the specific SS yield (SSY: 0.5-46 t km-2 yr-1) was strongly influenced by the flow regime. In the Carapelle River, the high values of the annual runoff coefficient (14-35%) and SSY (89-745 t km-2 yr-1) were related to clay and limestone lithology. Most of the annual SSY was transported during floods. In the Búger River, SSY and maximum SSC (SSCmax) were correlated with the runoff, peak discharge, and antecedent rainfall. In the Carapelle River, SSY and SSCmax were correlated to the amount and intensity of rainfall. The catchment size played an important role in the hysteretic behavior since it had an influence on the spatial rainfall and sediment sources distribution. Búger River showed predominant clockwise loops as SS sources were close to the outlet. In the Carapelle River basin, clockwise and counter-clockwise were generated as the larger agricultural area promoted a huge sediment availability.Lithology and geological characteristics resulted in the most relevant drivers controlling the hydrological regime and river type classification, meanwhile, rainfall was a less relevant factor. Land use and management practices were also relevant factors in SSY, determining the availability of suspended sediment material. At the event scale, a non-linearity in the rainfall-runoff relationship was found for both catchments, as runoff response can be due to different processes (i.e., saturation or infiltration excess).This work was supported by the research project CGL2017-88200-R “Functional hydrological and sediment connectivity at Mediterranean catchments: global change scenarios –MEDhyCON2” funded by the Spanish Ministry of Science, Innovation and Universities, the Spanish Agency of Research (AEI), the European Regional Development Funds (ERDF), the project “Soil Erosion in Apulia: Monitoring, Modelling and Control Strategies” performed within University of Bari and funded by the Apulia Basin Authority and the COST Action CA15113 Science and Management of Intermittent Rivers and Ephemeral Streams (SMIRES).

[In this study, the simulations generated by two of the most widely used hydrological basin-scale models, the Annualized Agricultural Non-Point Source (AnnAGNPS) and the Soil and Water Assessment Tool (SWAT), were compared in a Mediterranean watershed, the Carapelle (Apulia, Southern Italy). Input data requirements, time and efforts needed for input preparation, strength and weakness points of each model, ease of use and limitations were evaluated in order to give information to users. Models were calibrated and validated at monthly time scale for hydrology and sediment load using a four year period of observations (streamflow and suspended sediment concentrations). In the driest year, the specific sediment load measured at the outlet was 0.89 t ha-1 yr-1, while the simulated values were 0.83 t ha-1 yr-1 and 1.99 t ha-1 yr-1 for SWAT and AnnAGNPS, respectively. In the wettest year, the specific measured sediment load was 7.45 t ha-1 yr-1, and the simulated values were 8.27 t ha-1 yr-1 and 6.23 t ha-1 yr-1 for SWAT and AnnAGNPS, respectively. Both models showed from fair to a very good correlation between observed and simulated streamflow and satisfactory for sediment load. Results showed that most of the basin is under moderate (1.4-10 t ha-1 yr-1) and high-risk erosion (> 10 t ha-1 yr-1). The sediment yield predicted by the SWAT and AnnAGNPS models were compared with estimates of soil erosion simulated by models for Europe (PESERA and RUSLE2015). The average gross erosion estimated by the RUSLE2015 model (12.5 t ha-1 yr-1) resulted comparable with the average specific sediment yield estimated by SWAT (8.8 t ha-1 yr-1) and AnnAGNPS (5.6 t ha-1 yr-1), while it was found that the average soil erosion estimated by PESERA is lower than the other estimates (1.2 t ha-1 yr-1).object Object]

Excessive use of mineral fertilizers and inappropriate tillage operations are two main drivers of land degradation. The European Green Deal (EUGD) aims to restore the natural functions of ground and surface soil by 2030. EU Member States will be called upon to include mitigation measures in their own management programs. In this context, the current work aimed to evaluate the feasibility of Best Management Practices (BMPs), generally used to counteract soil erosion, in achieving nutrient load reduction, and evaluate their economic convenience in the private and public sector. The Soil and Water Assessment Tool (SWAT) was used to model point and diffuse nutrient sources in the Carapelle basin (Apulia, Italy) and to simulate BMP scenarios. Contour farming (CF), no tillage (NT), reforestation (RF), and two additional scenarios, including the 20% reduction of fertilizers in CF and NT, (CFR) and (NTR), were simulated following the EUGD strategy. For the current land uses, the riverine export of nitrogen (TN) and phosphorous (TP) were ∼49 kg ha-1y-1 and ∼0.044 kg ha-1y-1, respectively. CF and NT increased N-NO3 load both into surface runoff and in terms of leaching. Conversely, RF showed a reduction of N-NO3 losses. CFR and NTR scenarios decreased N-NO3 load both in surface runoff and leached of ∼20%. CFR and NTR represented the best alternative among the analyzed scenarios both for their lower production costs at the farm level and for their savings in terms of nutrient and soil losses. RF was economically profitable in sloped areas, thus representing BMPs that may be implemented in combination with other practices to have a greater impact at the basin scale. BMP implementation requires significant investments (public and private). The results of this study provide the scientific basis for decision-making for agriculture and watershed management.

Erosion is the most widespread form of soil degradation in Europe. EU Member States are called to identify areas prone to high risk of soil erosion and to adopt Best Management Practices (BMPs) to decrease land degradation. This study is aimed at identifying effective BMPs and their economic feasibility for controlling soil erosion in south-central Italy where lands are largely cultivated with winter wheat. The Soil and Water Assessment Tool (SWAT) was applied to simulate the baseline hydrologic and soil erosion processes of the Carapelle basin in the Puglia region, Italy. Calibrated sediment loads were reasonably accurate when statistically evaluated against measured data (R = 0.5, NSE = 0.5, PBIAS=-2.8 %). The model performed equally well for simulating stream flow rates (R = 0.6, NSE = 0.6, PBIAS = 5.3 %). The model maintained reliable performance during the validation period as well. Average annual specific sediment load was estimated 5.95 t ha yr mostly contributed by cultivated croplands. Based on regional agricultural policies, four management scenarios were implemented using the calibrated SWAT model: contour farming (BMP1), no tillage (BMP2); reforestation (BMP3) and contour farming and reforestation (BMP4). A threshold of sediment yield greater than 10 t hayr was selected to discretize target treatment areas where these BMPs were applied. Result show that combining contour farming and reforestation (BMP4) was the most effective (38 % reduction; from 5.95 to 3.70 t ha) for erosion control, followed by BMP2 (29 %; from 5.95 to 4.20 t ha), BMP1 (22 %; from 5.95 to 4.61 t ha) and BMP3 (15 %; from 5.95 to 5.04 t ha). An analysis of the farmer return-production cost ratio (FR/PC) indicated that the baseline (conventional tillage) and BMP1 were both economically sustainable in areas with slope 20 %. The results show that a program of measures can be effective for controlling soil erosion but it must be implemented over long time frames and it requires relevant investments from the public and private sectors.

International audience; Flow and the sediment regime affect water quality and nutrient delivery in all river systems and are fundamental in sustaining the river ecosystem. This study aims to identify the most relevant factors affecting the flow regime and the suspended sediment transport in two Mediterranean intermittent rivers: the Búger (Spain) and the Carapelle (Italy). A set of hydrological indicators were used to characterize and classify the flow regime. Highresolution data, streamflow and suspended sediment concentration were used to quantify runoff and sediment yields at different temporal scales (annual, monthly, event). Rainfall, streamflow and sediment variables were used at the event scale to assess the rainfall-runoff-suspended sediment relationship through the Pearson correlation matrix. Hysteresis analysis provided information on sediment source dynamics. In the Búger River, the high degree of flow intermittence was mainly due to the presence of carbonate lithology and forest land use at headwaters promoting low values of runoff coefficient (2-10%) and specific suspended sediment yield (SSY; 0.5-46 t km −2 y −1). In the Carapelle River, the high values of annual runoff coefficient (14-35%), together with low flow intermittence and SSY (89-745 t km −2 y −1) were related to clay and flyschoid lithology. Most of the annual sediment yield (SY, t) was transported during floods. In Búger, SSY and maximum suspended sediment concentration (SSC max, g l −1) were checked against runoff, peak discharge and antecedent rainfall. In Carapelle, SSY and SSC max were checked against the amount and intensity of rainfall. The catchment size and the spatial distribution of rainfall, land uses and lithology played important roles in the flow regime, suspended sediment transport and hysteretic behaviour. Characterization of the flow regime linked to its main physical drivers improved understanding of the hydrological response and sediment transport variability of intermittent rivers. This study provided valuable insights into water resource management, improving the prediction of spatial patterns and of the intensity of sediment transport in river basins.

In this work, a new nitrogen load apportionment tool was developed to quantify the anthropogenic pressures from point sources and diffuse sources (DSs) on the water in a basin, and to identify the areas contributing most of the total nitrogen (TN). The model, which is an alternative approach to complex conceptual models, was tested in the Canale d’Aiedda Basin (SE Italy). It integrates the TN soil system budget (SSB), TN riverine export (NRE) and TN export coefficient modelling. The results of the SSB showed a TN surplus for productive land (∼60 kg ha−1 yr−1). Major TN inputs were derived from fertilisers (∼89 kg ha−1 yr−1, 77% of the total input) and animal manure (∼13 kg ha−1 yr−1, 11% of the total input). Crop uptake was the main output (∼39 kg ha−1 yr−1, 70% of the total output). NRE was estimated through the measurement of streamflow and TN concentrations in two stream sections. The average NRE per unit area of productive land was 5.22 kg ha−1 yr−1. Groundwater was the major receptor of the TN from DSs. The TN runoff export coefficients, estimated on the basis of environmental factors and calibrated with riverine load measurements, were lower than the TN leaching fractions. The results show that setting export coefficients based only on environmental factors, without any calibration, leads to an overestimation of TN load in runoff, and to an underestimation of TN load in leaching.

This study aims to evaluate the suitability of the Soil and Water Assessment Tool model in simulating runoff and sediment loss in the Carapelle (SE Italy), a typical Mediterranean watershed, where continuous measurements of streamflow and sediment concentration were collected over a 5-year period, on a half-hour timescale, processed on a daily timescale. After sensitivity analysis, the model was calibrated and validated for runoff and sediment. Statistics show generally satisfactory efficiency. To further improve sediment simulation performance, we used a seasonal calibration scheme, in which data recorded in the dry and wet seasons were used to calibrate sediments separately, on a seasonal basis. We also tested the model's capability in identifying the major sediment source zones and river segments where there is sediment deposition. On the basin scale, the average water yield (186 mm) corresponds to 27% of the total rainfall (686 mm), and average annual sediment load was estimated to be 6.8 t ha-1 year-1. On the subbasin scale, a gradient of sediment yield was found that is characterised by a large difference among the upper (7 to 13 t ha-1 year-1), central, and lower parts (