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This paper mainly aims to illustrate an irrigation management tool to simulate scheduling of district-level water needs over the course of an irrigation season. The tool is mostly based on a daily model for simulating flow of water (and solutes) in heterogeneous agri-environmental systems (called FLOWS-HAGES). The model produces information on the daily evolution of: soil water contents and pressure potentials in the soil profile; water uptake and actual evapotranspiration; stress periods for each crop; return fluxes to the groundwater and their quality in terms of solute concentrations (e.g., nitrates). FLOWS-HAGES provides a daily list of hydrants to be operated according to water or crop-based criteria. The daily optimal sequence of hydrant use may thus be established by passing the volumes to be delivered on to the model for simulating the hydraulics of the irrigation network, in order to ensure that the discharges flowing inside the network of distribution pipes are delivered under optimal pressure head distribution in the system. All the above evaluations can be carried out in a stochastic framework to account for soil heterogeneity and climate changes. To illustrate the potential of FLOWS-HAGES, a case study was considered for a selected sector of the Irrigation District 10 in the “Sinistra Ofanto” irrigation system (southern Italy, Apulia region). In a 139 ha area (Sector 6 of the Irrigation District), soil profiles were analyzed for characterization of hydraulic properties variability. Hydraulic properties were determined by a combination of field and laboratory measurements. Model simulations were validated by comparing soil water storage simulated and measured by a sensor based on electromagnetic induction technique. Irrigation water volumes and frequency calculated by the model were compared to the volumes actually supplied by the farmers. Compared to the farmers behavior, the model simulates more frequent irrigations with lower irrigation volumes. Finally, some indexes of irrigation performance were calculated for each farm under study. The resulting maps provide useful information on the spatial distribution of farmer behavior, indicating the abuse or underuse of water as well as the fraction of the water lost by drainage following the irrigation method applied. [ABSTRACT FROM AUTHOR]

Nowadays, some of the existing irrigation distribution networks (IDNs) are facing hydraulic performance problems, due partly to the ageing of pipe networks, initial design flaws, improper management or/and the increase in water demand. Rehabilitation of these networks may become an inevitable need to provide the best services to farmers. To this end, a comprehensive computer model was developed to assist planners and decision makers in the determination of the most cost-effective strategy for the rehabilitation of irrigation networks. This model incorporates an innovative algorithm for the automatic search of the best looping positions in the network. Two multi-objective optimizations were applied for the rehabilitation of a real medium-size network operating on-demand and by gravity, one included the looping option while the other excluded this option. The two Pareto fronts, associated with each optimization, clearly indicated that it is imperative to consider the localized loops option during the rehabilitation process as it provided superior cost-effective solutions. The comparison between two selected cases from each front showed that even though the two solutions offered the same magnitude of improvement to the network, a cost saving of about 77% is obtained by choosing the case with the looping option. The model developed in the framework of this work represents a powerful optimization tool for cost-effective rehabilitation of irrigation networks. [ABSTRACT FROM AUTHOR]

One of the major shortcomings of the Participatory Irrigation Management/Irrigation Management Transfer (PIM/IMT) programs undertaken in many countries of the world, is the predominant absence of Monitoring & Evaluation (M&E) systems specifically addressed to accompany these processes, and become a major instrument to correct, improve and learn. To contribute to closing this gap, this paper presents the main features of 'MONEVA', an M&E system tailored to PIM/IMT programs, and adapted to different Mediterranean Countries. The system is based on the principles of the Logical Framework Analysis (LFA), which permitted the development of objectives, outcomes, outputs and appropriate indicators for the monitoring of results. MONEVA is integrated with seven menus and many submenus which detailed description is reported in the embedded User's Manual. Only selected options are presented in this paper. The important and innovative features of MONEVA are its capacity to adapt to every country by using only the indicators relevant to the country, and a simple and objective system of evaluation. The results of its application in the pilot countries Jordan and Tunisia, i) demonstrated its flexibility to adapt to local contexts and the easiness of its application which supported its adoption, and ii) validated its characteristics as a Decision Support System (DSS), having a great potential for improving the implementation of the PIM/IMT programs, through the identification of their criticalities and thus, facilitating the definition of corrective actions at government and agency levels, but particularly, at the Water Users' Association (WUA) level. [ABSTRACT FROM AUTHOR]

This paper deals with the issue of monitoring the horizontal and vertical distribution of bulk electrical conductivity, σb, in the soil root zone by using Electromagnetic Induction (EMI) sensors under different water and salinity conditions. In order to deduce the actual distribution of depth-specific σb from EMI depth-weighted apparent electrical conductivity (ECa) measurements, we inverted the signal by using a regularized 1D inversion procedure designed to manage nonlinear multiple EMI-depth responses. The inversion technique is based on the coupling of the damped Gauss-Newton method with truncated generalized singular value decomposition (TGSVD). The ill-posedness of the EMI data inversion is addressed by using a sharp stabilizer term in the objective function. This specific stabilizer promotes the reconstruction of blocky targets, thereby contributing to enhance the spatial resolution of the EMI reconstruction. Time-Domain Reflectometry (TDR) data are used as ground-truth data for calibration of the inversion results. An experimental field was divided into four transects 30 m long and 2.8 m wide, cultivated with green bean and irrigated with water at two different salinity levels and using two different irrigation volumes, to induce different salinity and water contents within the soil profile. For each transect, 26 regularly spaced monitoring sites (1 m apart) were selected for soil measurements using a Geonics EM-38 and a Tektronix Reflectometer. Despite the original discrepancies in the EMI and TDR data, we found a significantly high correlation of the means and standard deviations of the two data series, especially after filtering the TDR data. Based on these findings, the paper introduces a novel methodology to calibrate EMI-based electrical conductivity via TDR direct measurements by simply using the statistics of the two data series. [ABSTRACT FROM AUTHOR]

The paper assessed the sensitivity of an integrated hydro-economic model, to provide a quantitative range of uncertainty in the impacts of climate change on water balance components and water use in the agricultural sector of Apulia region located in a semi-arid Mediterranean climate area in southern Italy. Results show that the impacts of climate change are expressed in the future by an increase in the net irrigation requirements (NIRs) of all crops. Total cultivated land is reduced by 8.5 % in the future, and the percentage of irrigated land decreases from 31 to 22 % of total agricultural land. Reduction in the irrigated land, together with the variation in the cropping pattern and the adoption of the different irrigation techniques, led to a decrease in water demand for irrigation across the entire region. The sensitivity analysis shows that the groundwater recharge has the lowest correlation to climatic parameters. Results are addressed to the scientific community and decision makers to support the design of adequate adaptation policies for efficient water management under the severe drought conditions that are likely to occur in the region according to climate change projections. [ABSTRACT FROM AUTHOR]

The evapotranspiration (ET) represents the Crop Water Requirements that must be provided by rainfall and/or irrigation to ensure the crop yield. A critical need for farmers and water managers is to have a reliable, accurate and reasonably accessible estimation of the ET rates of crops to optimize their irrigation scheduling and ensuring long-term water sustainability. This is true especially for arid and semiarid areas characterized by limited availability of water resources and high competitiveness among users and different sectors. Remote sensing provides reliable information for the quantification of ET over large areas and the availability of free of charge high-resolution remotely sensed imagery provides the possibility of better understanding of seasonal climate and vegetation variability.In the present work were tested the capabilities of the "Analytical Approach" to estimate the seasonal ET at irrigation district scale over a complex agro-climatic study area characterized by an extremely heterogeneous, fragmented landscape and a semi-arid Mediterranean climate. The method is based on the logic of the Penman-Monteith equation and on the standard single crop coefficient (Kc) approach proposed by the Food and Agriculture Organization (FAO). It combines agrometeorological data measured in-situ (air temperature and humidity, solar radiation and wind speed) with surface reflectance satellite derived data: the albedo (α) of the crop-soil surface and the Leaf Area Index (LAI). The test was conducted over the Irrigation scheme "Sinistra Ofanto" (northern of the Apulia Region, Italy) using the Sentinel-2 derived biophysical vegetation's parameters and the agrometeorological data measured by the "Consorzio per la Bonifica della Capitanata" which manage the irrigation scheme. Results were compared at irrigation district scale using the global MODIS ET products (MOD16A2 and MYD16A2 Version 6) characterized by lower spatial resolution (500 meters) and daily temporal resolution. [ABSTRACT FROM AUTHOR]