This paper presents the results of a study which characterizes the hydrological regime of a temporary river at reach scale and analyzes the hydrological alterations due to anthropogenic pressures using the SWAT model to estimate the daily streamflows and the periods without flow which would occur in natural conditions. The study area is the Salsola and Celone river basins, located in SE Italy. In a first part, we identified six classes of flow, the so-called Aquatic States (ASs), which play a major role in determining the available mesohabitats and subsequently the characteristics of the aquatic life. The monthly occurrence of the different ASs over a long period has been evaluated in order to provide useful information to design biological samplings. The results show that dry bed conditions can occur from May to January and arheic state from April to January in the reaches located in the upper part of the basin. The impacted river reaches showed a different behavior depending on the anthropogenic impacts. In a second part, two indicators based on the statistics of the periods without flows were used, monthly flow permanence and dry season predictability, for describing the flow regime components which may have been altered by anthropogenic pressures. The indexes, which were computed in impacted and natural conditions, were used as coordinates in a plot to obtain a graphical vision of the regimes. The distance between the points representing the actual (impacted) and natural states in the plot were used to classify the hydrological alterations.

In a catchmnent, nitrogen (N) export from terrestrial ecosystems to rivers is controlled by the hydrologicalprocesses and N balance. In the present paper, the soil system N budget and riverine exportwere quantified in a Mediterranean watershed, the Celone (South-East, Italy). The study area (72 km2)consists of agricultural land (70%) and deciduous forests with three small residential areas. Major Ninputs derived from fertilizers and animal manure, corresponding for the whole watershed area to 68and 12 kg N ha-1 yr-1, respectively. N input from point sources was 1% of total input and atmosphericdepositions measured in a gauging station near the study area was quantified in ~6 kg N ha-1 yr-1. CropN uptake was the main N output from agricultural land; it was estimated in ~37 kg N ha-1 yr-1 by usingdata on crop yields provided by local farmers. Total flux of N in surface water was quantified for a year atthe outlet of the study area by using continuous measures of flow and discrete measures of N concentrationscarried out with a different frequency during the normal and low flow and when floods occurred.The hydrological regime of the stream, which is a temporary river, plays an important role in N transport.Water quality was found to vary considerably through the year in terms of both nutrient concentrationsand loads. Riverine N export was quantified in 41% of total N input, and it was mainly transported duringflood events, ~60% of the annual load was delivered during floods occurred in 38 days. Organic nitrogenand nitrate were the main N forms in surface water, and the contribution per hectare was about24 and 14 kg N, respectively. On a yearly basis, the difference between N inputs and outputs includingriverine export was estimated in about 4 kg N ha-1 yr-1 for the whole watershed area. This amount partlyaccumulates in soils in different N forms and the remaining part, mainly in form of nitrate, percolatesthrough unsaturated soiltowards groundwater. This study reports an important analysis of N pollution ina Mediterranean watershed with a temporary river system and limited data availability. Data acquisitionand handling have proved to be an important challenge to overcome in N balance quantification. Theresults and the methodology of the present work can be useful for understanding nitrogen loss dynamicsand for functional water management and land use planning.

In this paper, we present an approach to evaluate the hydrological alterations of a temporary river. In theserivers, it is expected that anthropogenic pressures largely modify low-flow components of the flow regime with consequencesfor aquatic habitat and diversity in invertebrate species. First, by using a simple hydrological index (IARI) riversegments of the Celone stream (southern Italy) whose hydrological regime is significantly influenced by anthropogenicactivities have been identified. Hydrological alteration has been further classified through the analysis of two metrics: thedegree (Mf) and the predictability of dry flow conditions (Sd6). Measured streamflow data were used to calculate the metricsin present conditions (impacted). Given the lack of data from pristine conditions, simulated streamflow time serieswere used to calculate the metrics in reference conditions. The Soil and Water Assessment Tool (SWAT) model wasused to estimate daily natural streamflow. Hydrological alterations associated with water abstractions, point dischargesand the presence of a reservoir were assessed by comparing the metrics (Mf, Sd6) before and after the impacts. The resultsshow that the hydrological regime of the river segment located in the upper part of the basin is slightly altered, while theregime of the river segment downstream of the reservoir is heavily altered. This approach is intended for use with ecologicalmetrics in defining the water quality status and in planning streamflow management activities.

Information describing the hydrological regime is likely to play a major role in the implementation of the WFD across the EU. In fact, the flow regime is one of the drivers of the ecological status of a stream. The analysis of the hydrological regime is particularly important to understand the ecological status in intermittent rivers since the flow varies on spatial and temporal scale depending on precipitation patterns. A method for analysing the flow regime for intermittent rivers is proposed in order to help in the design of the schedule for biological samplings. Climatic data were used as a guide to hydrological regime and an analysis of daily flow data was done to define low flow and dry periods, extreme flow conditions and response to rainfall events.

The potential impacts of future climate scenarios on water balance and flow regime are presented and discussed for a temporary river system in southern Italy. Different climate projections for the future (2030-2059) and the recent conditions (1980-2009) were investigated. A hydrological model (SWAT) was used to simulate water balance at the basin scale and streamflow in a number of river sections under various climate change scenarios, based on different combinations of global and regional models (GCMs and RCMs). The impact on water balance components was quantified at the basin and sub-basin levels as deviation from the baseline (1980-2009), and the flow regime alteration under changing climate was estimated using a number of hydrological indicators (IHA). An increase in mean temperature for all months between 0.5-2.4°C and a reduction in precipitation (by 4-7%) was predicted for the future. As a consequence, a decline of blue water (7-18%) and total water yield (11-28%) was estimated. Although the river type classification remains unvaried, the flow regime distinctly moves towards drier conditions and the divergence from the current status increases in future scenarios, especially for those reaches classified as I-D (i.e. Intermittent-Dry) and E (Ephemeral). Hydrological indicators showed a decrease in both high flow and low flow magnitudes for various time durations, an extension of the dry season and an exacerbation of extreme low flow conditions. A reduction of snowfall in the mountainous part of the basin and an increase in potential evapotranspiration was also estimated (4-4.4%). Finally, the paper analyses the implications of the climate change for river ecosystems and for River Basin Management Planning. The defined quantitative estimates of water balance alteration could support the identification of priorities that should be addressed in upcoming years to set water-saving actions.

The Celone River Basin (Puglia, Italy) is characterized by a diffuse pollution from agricultural sources. Like most intermittent rivers in the Mediterranean area, this stream is not well monitored; only few water quality data are available. Thus, due to high variability in streamflow and nutrient concentrations, which characterizes this type of rivers, it is difficult to estimate accurately nutrient loads from point and non point sources and consequently anthropogenic activities impact on the river. In this work, a detailed study was carried out on the Celone river to identify the chemical characteristics of the water and to quantify the annual nutrient loads delivered to the downstream reservoir. An automatic sampler and a flow module were set up in a section of the river. Continuous measures of flow were carried out using a different frequency for water sampling when floods occurred and during normal or low flow state. Nutrient concentrations in the water samples were accurately determined in laboratory. Water quality of the river was found to vary considerably along the year in,terms of nutrient concentration. Nitrate and total phosphorus are the main cause of water pollution. Nutrient losses by surface runoff were essentially a winter process. The contribution per hectare of non point sources can be estimate at about 39 kg/ha of total nitrogen and 2.4 kg/ha of total phosphorus. Estimates of loads in terms of TN and TP for the 21-day period of flood were calculated in 55 and 81% of annual loads, respectively. This study clearly demonstrates the importance of flood event contribution to the annual nutrient load.

in this work, a detailed study was carried out on the Celone river to quantify the nutrient loads delivered to the downstream reservoir on seasonal and annual time scale. An automatic sampler and a flow module were set up in a section of the river. Continuous measures of flow were carried out using a different frequency for water sampling when floods occurred and during normal or low flow state. Nutrient concentrations in the water samples were occurately determined in laboratory. Water quality of the river was found to vary considerably along the year in terms of nufrient concentration. Nitrate and total phosphorus are the moin cause of water pollution. Nutrient losses by surface runoff were essentially a winter process. The contribution per hectare of non poini sources can be estimoted at about 39 kg/ha of total nitrogen and 2.4 kg/ha of total phosphorus. Estimates of loads in terms of TN ond TP for the 21-day period of flood were calculated in 55 and 81 % of annual load, respectively.

As most of the rural areas inMediterraneanRegion,the Celone river basin (Apulia, Italy) is characterized by diffusepollution from agriculture. Nutrient export from terrestrialecosystem to the river is controlled by hydrologicalprocesses and nutrient input frompoint and non-point sources.In the present paper, anthropogenic nitrogen input and theriverine export of nitrate-N (N-NO3) were quantified throughseveral survey campaigns, continuousmeasures of streamflowand discrete determinations of concentrations. A differentfrequency for water sampling was used, respectively, duringfloods and during normal- or low-flow state. Nitrate-N concentrationsin surface waters were found to vary considerablyacross the seasons. The riverine N-NO3 export was estimatedto be about 14 kg N ha-1 year-1. Major N inputs derivedfrom fertilizers and animal manure correspond to 68.2 and24 kg N ha-1 year-1, respectively. Nitrate-N fluxes instreamduring flood events (21 days) accounted for about 63%of the annual loading. This study clearly demonstrates theimportance of flood event contributions to the annual nutrientloading delivered to the reservoir and that more efficient fertilizersand management practices are needed to reduce Ninput.

Hydrological indicators (HIs) are commonly used in eco-hydrological studies (i.e. environmental flow and hydrological status assessment). Their computation is based on streamflow data, and if measured data are not available, hydrological models can be used to generate flow data. The present paper describes a study that aimed to predict streamflow in a temporary river and to analyze the general reliability of some hydrological indicators evaluated by using simulated data instead of measured flow data. The SWAT model was used to predict daily streamflow in a river section of the Celone river (Puglia, Italy). Several HIs characterizing the patterns of river flow or specific hydrological components were evaluated using observed and simulated streamflow. The results show that the SWAT model is able to simulate streamflow in temporary river systems, but its performance under extreme low flow conditions may be a weak point. When simulated streamflow time series were used, the replicability of the HIs evaluated using a rigorous statistical methodology ranged from good to limited. Good performance was found for the magnitude of discharge in wet months (average monthly flow from November to May), for the high flow indicators (annual maxima, 1-, 3-, 7-, 30-, 90-day mean flow) and timing, while limited performance was detected for low flow indicators (annual minimum 1-, 3-, 7-, 30-, 90-day mean flow) and the number of zero flow days. Better performance for low flow indicators was found after introducing the zero-flow threshold. This type of eco-hydrological study may contribute to characterizing the flow regime and its alterations in regions with scarce data.

In the Mediterranean region suspended sediment transport is the predominant process in sediment export in most river basins. The aim of this paper is to analyze suspended sediment variability over a period of 12 months in the Celone river, a temporary river located in the Puglia region (SE-Italy), and to evaluate sediment rating curves for estimating suspended sediment concentrations for subsequent load calculations. Similarly to most temporary rivers, the Celone river shows relevant differences among mean daily flows and the extreme instan-taneous flows during floods. To take into account these peculiarities, the rating curves were developed as a func-tion of hydrological conditions: high, normal and low flows. Continuous measures of streamflow and frequent samplings of suspended solid concentrations (SSCs) during flood events, normal flow and low flow were used. The plot of the SSC against discharge takes the form of a hysteresis loop. Clockwise, anticlockwise and mixed-shaped loops were observed. Suspended sediment yield was found to be in the range of 250-384 t km -2 y -1 . The results show that about 94% of the total suspended materials were transported during the high flow regime, while less than 0.1% were under low flow conditions. Moreover, it was observed that 90% of the total annual suspended loads were moved between November to May. Flash floods that occur in summer exhibit the highest values of SSC. The proposed method, which was based on sediment rating curves, has proved to be valuable to generate SSC data for high and normal flows although it tends to underestimate the highest values. It can repre-sent a useful tool for water resource managers who need a quick and inexpensive method, specific for temporary rivers, to evaluate suspended sediment yield.

The evaluation of the "Hydrological Status" (HS) of a water body in a catchment is of the greatest importance in order to achieve the final objective of the European Water Framework Directive (WFD). It represents the distance of the actual hydrological regime from its natural condition and it may be responsible for the ecological status of a river. The WFD doesn't provide specific guidelines or recommendations on how the alterations should be evaluated and quantified. In this paper a new approach to evaluate the Hydrological Status of a temporary river was tested. The flow regime of a river has been classified through the analysis of two metrics: the degree and the predictability of dry flow conditions which were evaluated on monthly streamflow data. Both indeces were also used as indicators to assess the river's natural flow regime and its alterations. This method was applied to the Candelaro river basin (Puglia, Italy) where we had to face the problem of limited data availability. The SWAT model was used when streamflow data were not available, and a GIS procedure was applied to estimate potential water abstractions from the river. Four types of rivers were identified whose regimes may exert a control on the aquatic life. By using the two metrics as coordinates in a plot a graphic representation of the regime can be visualized in a point. Hydrological perturbations associated with water abstractions, point discharges and the presence of a reservoir were assessed by comparing the position of the two points representing the regime before and after the impacts. The method is intended to be used with other biological metrics in order to defining the ecological status of a stream. It is a useful tool when identifying river bodies under hydrological pressures and it can be used in planning the "measures" towards the WFD goals.

In achieving the final objective of the European Water Framework Directive, the evaluation of the 'hydrological status' of a water body in a catchment is of the utmost importance. It represents the divergence of the actual hydrological regime from its 'natural' condition and may thus provide crucial information about the ecological status of a river. In this paper, a new approach in evaluating the hydrological status of a temporary river was tested. The flow regime of a river has been classified through the analysis of two metrics: the permanence of flow and the predictability of no-flow conditions that were evaluated on monthly streamflow data. This method was applied to the Candelaro river basin (Puglia, Italy) where we had to face the problem of limited data availability. The Soil and Water Assessment Tool model was used when streamflow data were not available, and a geographic information system procedure was applied to estimate potential water abstractions from the river. Four types of rivers were identified whose regimes may exert a control on aquatic life. By using the two metrics as coordinates in a plot, a graphic representation of the regime can be visualized in a point. Hydrological perturbations associated with water abstractions, point discharges and the presence of a reservoir were assessed by comparing the position of the two points representing the regime before and after the impacts. The method is intended to be used with biological metrics in order to define the ecological status of a stream, and it could also be used in planning the 'measures' aimed at fulfilling the Water Framework Directive goals. © 2014 John Wiley & Sons, Ltd.

In this paper, the results obtained from multivariate statistical techniques such as PCA (Principal component analysis) and LDA (Linear discriminant analysis) applied to a wide soil data set are presented. The results have been compared with those obtained on a groundwater data set, whose samples were collected together with soil ones, within the project "Improvement of the Regional Agro-meteorological Monitoring Network (2004-2007)". LDA, applied to soil data, has allowed to distinguish the geographical origin of the sample from either one of the two macroaeras: Bari and Foggia provinces vs Brindisi, Lecce e Taranto provinces, with a percentage of correct prediction in cross validation of 87%. In the case of the groundwater data set, the best classification was obtained when the samples were grouped into three macroareas: Foggia province, Bari province and Brindisi, Lecce and Taranto provinces, by reaching a percentage of correct predictions in cross validation of 84%. The obtained information can be very useful in supporting soil and water resource management, such as the reduction of water consumption and the reduction of energy and chemical (nutrients and pesticides) inputs in agriculture.

In the Mediterranean region, suspended sediment transport is the predominant process of material removaland sediment transport. The aim of this paper is to analyze the sediment dynamics and to compare differentcalculation methods in order to identify the most suitable for temporary rivers. At this purpose, continuousmeasurements of the flow and discrete values of sediment concentrations recorded from 2010 to 2011 havebeen used. Sampling was carried out with different frequencies as a function of the flow conditions. Severalcalculation methods were compared: Averaging Estimator Methods, Ratio Estimator Methods e RegressionEstimator Methods. The suspended sediment load was estimated in the range of 141-1123 tkm-2yr-1. Applyinga flow regime Stratification based on a flow exceeded frequency (f1<20%; 20%<f2<80%; f3>80%),the range of values was found in a restricted interval 298-595 tkm-2yr-1. Results show that the stratificationapproach is necessary methodology in load fluxes estimation in temporary rivers.