Antonio Lo Porto

AgriBMPWater: systems approach to environmentally acceptable farming

To help local regulators mitigate non-point source agricultural pollution and implement environment-friendly agricultural practices, a comparison between different existing or simulated best management practices (BMPs) has been carried out within a pluridisciplinary project called AgriBMPWater (FP5 founded). The project has been imagined and built in a pluridisciplinary approach and framework. The approach developed corresponds to a cost/effectiveness assessment of several BMPs in several European watersheds, also including the study of their acceptability by farmers. Thanks to the integrated assessment of existing and potential BMPs, a selection grid contributes to provide assistance to regulators on how to conduct environmental, economic and sociological analyses for helping decision makers. Water quality problems encountered and dealt with in this project include nitrate, phosphorus, sediment, pesticide loads and acid water concerns. Thus, the developed framework allows for a large range of hydrological and economic models, depending on the environmental problem detected in each watershed.

Investigating hydrological regimes and processes in a set of catchments with temporary waters in Mediterranean Europe

Abstract Seven catchments of diverse size in Mediterranean Europe were investigated in order to understand the main aspects of their hydrological functioning. The methods included the analysis of daily and monthly precipitation, monthly potential evapotranspiration rates, flow duration curves, rainfall—runoff relationships and catchment internal data for the smaller and more instrumented catchments. The results showed that the catchments were less “dry” than initially considered. Only one of them was really semi-arid throughout the year. All the remaining catchments showed wet seasons when precipitation exceeded potential evapotrans-piration, allowing aquifer recharge, “wet” runoff generation mechanisms and relevant baseflow contribution. Nevertheless, local infiltration excess (Hortonian) overland flow was inferred during summer storms in some catchments and urban overland flow in some others. The roles of karstic groundwater, human disturbance and low winter temperatures were identified as having an important impact on the hydrological regime in some of the catchments.

Assessing flow regime alterations in a temporary river – the River Celone case study

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

Integrated Water Resources Management : STRIVER efforts to assess the current status and future possibilities in four river basins

The contemporary concept of Integrated Water Resources Management (IWRM) was primarily conceived for the purpose of promoting sustainable water management. There are many elements included in modern IWRM perceptions, e.g., natural resource utilization planning combined with at strategy to balance between social, economic and environmental objectives based on an overall sustainability concept. However, the concept behind IWRM is not new. The historical development of the concept of Integrated Water Resources Management (IWRM) can be found in Rahaman and Varis (2005).

Use of a watershed model in the development of a River Basin Management Plan in a catchment with limited data

The estimation of existing nutrients load in a river is often challenging due to scarcity of measured data. In this case the use of a computer model is really helpful to assess the water quantity and nutrient balance of a water body, particularly in watershed affected by water pollution.

Modeling Nutrients in the Rio Mannu River Basin: Scenario Analysis

The Rio Mannu River Basin (Sardinia, Italy) is experiencing an intensification of agriculture, and correspondingly, irrigation areas are increasing. Like many Mediterranean areas, this basin is characterized by water shortages and diffuse pollution from agricultural sources. It is than important to design, evaluate and adopt adequate management policies to prevent further water quality impairment. The Soil and Water Assessment Tool (SWAT), a model for agricultural watersheds, was applied to simulate hydrological processes and evaluate current and future nutrient loads. Several alternative scenarios were developed through discussions with stakeholders, and four of them were selected and simulated as realistic in consideration of the socio-economical situation in the study area. Scenario A involves agricultural practices that assume a reduction in fertilizer. Scenario B regards the reuse (in three sub-basins) of treated wastewater in fert-irrigation of olive trees instead of discharging it into the river system. Scenario C regards the partial substitution of durum wheat with sugar beet in a subset of the catchment. Scenario D introduces rapeseed and sunflower replacing durum wheat in an other small area. We assessed each option by considering the effects on water balance, water quality, crop yields and economic benefits. The model was able to simulate the hydrologic cycle and water quality notwithstanding an insufficient availability of measured data. This study suggests that a better use of fertilizers could substantially reduce the amount of nutrients flowing into surface waters, but the effects of such a policy on crop yield and farm income are in some cases negative. The reuse of treated effluent can results in a moderate reduction in nutrient load but in a larger reduction in nutrient concentration; it is more efficient in summertime and on soluble compounds (NO3, NH3 and min P); furthermore an application at larger scale of such scenario will result in very great results. The sugar beet scenario is the less competitive scenario: it features slightly higher loads and large increment in water resources usage. In the last scenario the release of several nutrient will increase; maybe a competitive scenario in terms of revenues for farmers coupled with a 6% reduction of water use in irrigation.

Modelling water-harvesting systems in a semi arid catchment (Merguellil-Tunisia)

In the Mediterranean regions, hydrologic processes are quite specific due to the temporal variability of precipitation characterized by a succession of drought and flash-flood periods. These processes may also have changed due to a range of human activities such as land use changes, dams building, soil and water conservations works. The Merguellil catchment (Central Tunisia) is a typical Mediterranean semi-arid basin which suffers regular water shortage aggravated by current drought. During the recent decades the continuous construction of small and large dams and Soil and Water Conservation Works (SWCW) (ie. Counter ridges) has taken place within the watershed. However, little is known about the effect of these water harvesting systems on the water balance components of arid watersheds. The work presented here attempts to simulate the actual water balance using the Soil and Water Assessment Tool (SWAT-2005) model including the water harvesting systems. Large dams are modeled as reservoirs, small dams as ponds, and contour ridges as potholes that fill with water, and increase the percolation into the aquifer.

Evaluation of Flow Regime in Mediterranean Streams Using Flashiness Index

In the Mediterranean region, precipitation is characterised by a high spatial and temporal variability; this has a great influence on the flow regime and extreme flow events of a stream. Flow regime, in turn, has multiple impacts on erosion and sediment delivery, non-point source pollutant transport and biological communities inhabiting a stream. This paper presents a study aimed at analysing the flow change rates of a number of Mediterranean streams using the Richards-Baker (R-B) Flashiness Index, which measures streamflow variations in response to rainfall events. The flashiness is affected by some basin characteristics: climate, topography, land use, management, soil type, and other factors. The R-B Index values were then related to watershed size, location and baseflow discharge. They were compared to the Aridity Index of the area, and the daily flow variation coefficient. The authors report that the R-B Index values in the studied basins, generally, show an increase over time. The intermittent rivers studied present a considerable inter-annual variation of this index, together with mean annual values higher than the permanent rivers studied. In the southern Mediterranean area, the rivers assume higher values of R-B Index than those located in the northern area. Streams draining small watersheds show a very flashy character, indicating a very quick response to rainfall. These results suggest further investigation to analyse flood events.