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40 Pags.- 5 Tabls.- 9 Figs. The definitive version is available at: http://link.springer.com/journal/271 ; Numerous studies have analyzed the solid-set sprinkler irrigation system performance. However, the effect of field-boundaries irrigation has not been considered in the whole-field performance. The objectives of this study were (1) to characterize two different solutions to irrigate field boundaries (full-circle sprinkler equipped with a deflecting plate, DP, and partial-circle sprinklers, PC); (2) to calibrate and validate a ballistic model to adequately simulate these solutions; and (3) to analyze the two different designs (DP or PC) from a whole-field perspective. Two types of experiments were designed. The first was carried out with an isolated sprinkler under no windy conditions to estimate drop size distribution parameters. The second was performed in a solid-set sprinkler layout under windy conditions to calibrate and validate the ballistic model. The experimental design allows the comparison of both solutions under equal technical and meteorological conditions. Comparisons between designs (DP or PC) were established for a whole-field area in terms of irrigation performance and crop yield. From a technical point of view, PC sprinklers perform better than DP sprinklers. From an economical point of view, the shape and orientation of the plot and the legal requirements of the irrigation system design (minimum distance of the sprinkler line to the border) have an important effect on the optimal solution to irrigate field boundaries. ; This research was funded by the MCINN of the Government of Spain through grants AGL2010-21681-C03-01, AGL2013-48728-C2-1-R and the FPI MINECO PhD grants program. ; Peer reviewed

45 Pags.- 3 Tabls.- 10 Figs. The definitive version is available at: http://www.sciencedirect.com/science/journal/03783774 ; Water application depth of a center-pivot (CP) irrigation system is not uniformly distributed across a field due to emitter package design, tower dynamics, and meteorological variability. The objective of this research was to measure and model the effect of the intra-irrigation meteorological variabilities on CP seasonal water distribution pattern and corn yield. The 2013 irrigation season of a commercial CP cropped with corn was analyzed. From 60 irrigation events applied to the corn, 10 were evaluated using radial catch cans. The mechanical movement of CP towers for the sixty irrigation events was characterized using Global Navigation Satellite System-Real Time Kinematic (GNSS-RTK) monitoring. Meteorological variables at 1 s frequency were measured with an automatic weather station installed in the farm. The ballistic model calibrated and validated for rotating spray plate sprinklers under different nozzle sizes and wind conditions was mounted on the CP lateral, following the correspondent sprinkler package. The CP lateral was moved following the measured or simulated tower dynamic, and the current or averaged meteorological conditions of each irrigation event were applied to the corn. Crop yield was simulated by coupling the water distribution pattern simulated under the different cases with the Ador-crop model. Differences were observed for simulated seasonal water distribution pattern of the CP under homogeneous wind conditions (averaged for each irrigation event) or under variable of time wind conditions (measures). Simulated yield considering discontinuous tower dynamics and intra-irrigation meteorological variability has the largest correlation coefficient with the measured corn yield. Other factors were not considered in the yield simulation as variability in nutrient availability, emergence problems, and diseases and soil variability could explain the differences between the simulated and measured corn yield. The intra-irrigation meteorological variability has an important effect on the water distribution pattern of windy irrigation events of CP systems. Depending on the wind speed along the crop season, the intra-irrigation variability will have a major or minor effect on seasonal water distribution pattern and crop yield variability. ; This research was funded by the Ministry of Economy and Competitiveness of the Spanish Government through the grants AGL2010-21681-C03-01 and AGL2013-48728-C2-1-R. ; Peer reviewed

53 Pags.- 16 Figs. The definitive version is available at: http://ascelibrary.org/journal/jhend8 ; Fast flows and avalanches of rock and debris are among the most dangerous of all landslide processes. Understanding and predicting postfailure motion (runout) of this kind of flowlike landslides is thus key for risk assessment, justifying the development of numerical models able to simulate their dynamics. In this paper a numerical method for the resolution of the depth-averaged debris flow model is presented. This set of nonlinear differential equations is formed by a variation of the shallow water equations, including strong bed slope, and a rheology resistance term. This paper focus on the numerical discretization of the resistance term, exploring three different approximations: pointwise, implicit, and unified. Well balance between numerical flux and source terms is only achieved using the unified discretization. In order to avoid nonphysical values of the water depth and discharge, a limitation of the unified resistance term is also needed. This correction is made following three conditions that identify the physical boundaries of the resistance term in the debris flow. This technique does not affect the computational efficiency of the method, keeping the original time step. Furthermore, proposed analytical test cases show that the three resistance limitations do not significantly perturb the numerical solution. The properties of the resulting numerical scheme are studied using a set of numerical experiments that include steady and transient flows. The results show the convenience of the unified discretization and the need of the three-condition limitation in order to avoid unphysical solutions. ; This research was supported by project Changing RISKS(OPE00446/PIM2010ECR-54900726)financed by EU FP7 ERANET CIRCLE Programme,and Grupo de Excelencia E68550 financed by the Aragón Government and the European Social Fund(ESF). ; CIRCLE Project reference:SSA-011793 ; Peer reviewed

42 Pags.- 3 Tabls.- 9 Figs. The definitive version is available at: http://ascelibrary.org/journal/jidedh ; The modernization of irrigation districts in Spain is based on the construction of collective pressurized networks equipped with remote control systems. In this paper, a simulation approach is used to explore the benefits of introducing a collective solid-set irrigation control software. The controller works in combination with a district management database, real-time evapotranspiration and meteorology information, and a remote control system. Controller decisions are based on the simulation of sprinkler irrigation performance and on crop-water balance. The decision to irrigate a plot can be guided by the use of two simulation parameters: the estimated application efficiency of the irrigation event (heavily affected by wind speed) and a crop-water stress index. Simulation experiments were performed in a district located at the Ebro basin of Spain. The collective controller resulted in water conservation (with respect to the current situation) of 2,234 and 4,664 m3ha-1 for corn and alfalfa, respectively, and in an increase in water productivity of up to 91%. Although additional research is needed to produce a reliable collective controller, these preliminary results are encouraging. ; This research was funded by the Plan Nacional de I+D+i of the Government of Spain, through Grant No. AGL2004-06675-C03-03 and by the CONSI+D of the Government of Aragón (Spain) through gant No. PIP090/2005. A. S. received a scholarship from the Agronomic Mediterranean Institute of Zaragoza (CIHEAM) ; Peer Reviewed

56 Pags.- 5 Tabls.- 8 Figs. The definitive version is available at: https://www.sciencedirect.com/science/journal/03783774 ; Simulation models of sprinkler irrigation are a valuable tool to improve the irrigation water management at plot scale. Ballistic theory has been commonly used to simulate drop dynamics in sprinkler irrigation models. A number of experiments on sprinkler irrigation performed in previous studies in the Ebro Valley Spain were analyzed and integrated in a data base. The evaluations were performed on six sprinkler types with different nozzle sizes, operating pressures under different meteorological conditions and spacings. The data base includes 40 isolated and 167 solid-set experiments that were processed with a self-calibrated model to calibrate and validate the ballistic parameters. The ballistic model used in this research was improved with respect to a previous model, moreover some novelties were added. These modifications were done in the phases of: the numerical solution, a wind drift and evaporation losses model, simulations considering slope in the terrain, drop generation (using regular and random methods), the size of the terrain cells where the drops are simulated and considering two drop size distributions, upper limit lognormal and Weibull. The results indicated larger and significant differences of Christiansen´s Uniformity Coefficient measured and simulated when considering a constant wind velocity (9%) and no differences when the wind velocity is defined for intervals equal to or less than 30 min (6%). Regarding the effect of the slope in the terrain, differences between both uniformity coefficients are relevant (11%) when the wind velocity is larger than 4 m s−1. Both drop size distributions were similar in accuracy however, the upper limit lognormal was more suitable to simulate a sprinkler especially designed to operate under low pressure. The predictive ability of the model once calibrated and validated was satisfactory (99% and 75%, respectively). The new model improves the accuracy with respect to previous research and minimizes the computing time for the calibration and validation processes using the cluster Trueno-CSIC. ; This research was funded by MICINN of the Government of Spain through grant AGL2013-48728-C2-1-R and AGL2017-89407-R. Octavio Robles received a scholarship granted by the Minister of Economy and Competitiveness of the Spanish Government. ; Peer reviewed

15 Pags.- 6 Figs.- 4 Tabls. This work was selected by the Organizing Committee of the XXXI Spanish National Irrigation Congress (XXXI Congreso Nacional de Riegos) to be submitted for publication in this journal. ; Ballistic simulation of the spray sprinkler for self-propelled irrigation machines requires the incorporation of the effect of the jet impact with the deflecting plate. The kinetic energy losses produced by the jet impact with the spray plate were experimentally characterized for different nozzle sizes and two working pressures for fixed spray plate sprinklers (FSPS). A technique of low speed photography was used to determine drop velocity at the point where the jet is broken into droplets. The water distribution pattern of FSPS for different nozzle sizes, working at two pressures and under different wind conditions were characterized in field experiments. The ballistic model was calibrated to simulate water distribution in different technical and meteorological conditions. Field experiments and the ballistic model were used to obtain the model parameters (D50, n, K1and K2). The results show that kinetic energy losses decrease with nozzle diameter increments; from 80% for the smallest nozzle diameter (2 mm) to 45% for nozzle diameters larger than 5.1 mm, and from 80% for the smallest nozzle diameter (2 mm) to 34.7% for nozzle diameters larger than 6.8 mm, at 138 kPa and 69 kPa working pressures, respectively. The results from the model compared well with field observations. The calibrated model has reproduced accurately the water distribution pattern in calm (r=0.98) and high windy conditions (r=0.76). A new relationship was found between the corrector parameters (K1' and K2') and the wind speed. As a consequence, model simulation will be possible for untested meteorological conditions. ; This research was funded by the MCINN of the Government of Spain through grants AGL2010-21681-C03-01 and the FPI-MINECO PhD grants program. ; Peer reviewed

33 Pags., 10 Figs. The definitive version is available at: http://www.springerlink.com/content/0342-7188/ ; A topographic three dimensional scanner is similar to a radiometric total station, but it does not require a reflecting prism and the optical measurement device is motorized and automated. With this device, very large survey data sets can be collected with moderate effort. In this paper, the application of a 3D scanner to surface and sprinkler irrigation research is presented and discussed. In surface irrigation, the scanner was successfully applied to: 1) the survey of soil surface elevation, including furrowed areas; 2) the determination of flow cross sections; 3) surveying the location of the advancing front; and 4) measuring water surface elevation. The device showed some limitations in the measurement range, which was limited to about 35 m for water surface elevation and 50 m for the detail survey of furrowed areas. In sprinkler irrigation, the scanner was applied to the survey of the sprinkler jet and the irrigation drops during their trajectory. The scanner seemed to fail to survey fine drops, since falling drops were rarely scanned in the vicinity of the sprinkler. Despite the reported limitations, the 3D scanner seems to be destined to occupy a relevant place in the irrigation research laboratory. ; This research was funded by the Plan Nacional de I+D+i of the Government of Spain, through grant AGL2007-66716-C03. We appreciate the cooperation of the surveying company "Scanner Patrimonio e Industria". ; Peer reviewed

31 Pags., 2 Tabls., 10 Figs. The definitive version is available at: http://ascelibrary.org/toc/jidedh/139/7 ; Ballistic simulation has been successfully applied to impact sprinklers. However, ballistic simulation of center pivot sprinkler irrigation has been limited by the difficulty in estimating the initial drop velocity vector in fixed and rotating spray plate sprinklers. Initial velocity is severely affected by the impact of the jet on the sprinkler deflecting plate (or plates). In this work, experimental techniques based on drop photography have been used to obtain the droplet velocity and angle in the vicinity of a fixed spray plate sprinkler by using three different nozzle diameters. Furthermore, simulation techniques based on the inverse solution of drop trajectory were combined to determine the initial velocity vector and energy loss at the spray. Our analysis suggests that the ballistic model can be used to simulate drop inverse trajectory in these sprinklers, although the ballistic model can benefit from 5 to 10% effective drag-force screening. The ratio of initial drop velocity to jet velocity was between 0.67 and 0.82, whereas the kinetic energy losses in the spray sprinklers amounted to 33–55%. ; This research was funded by the National Research, Development and Innovation Plan of the Government of Spain (Plan Nacional de I+D+I) through grant AGL2010-21681-C03-01, and by the Special Intramural Grant 200940I041 of CSIC (funding G. S´anchez Burillo). R. Delirhasannia received a scholarship from the Ministry of Science, Research and Technology 301 of Iran to perform a scientific stay at the Aula Dei Experimental Station of CSIC, Zaragoza, Spain. ; Peer reviewed

42 Pags.- 1 Tabl.- 12 Figs. The defintive publication is available at: http://link.springer.com/journal/271 ; The experimental data set used in the paper is OA available (http://hdl.handle.net/10261/127640) ; The characterization of drops resulting from impact sprinkler irrigation has been addressed by a number of techniques. In this article, a new technique based on low-speed photography (1/100 s) is presented and validated. The technique permits to directly measure drop diameter, velocity and angle. The photographic technique was applied to the characterization of drops resulting from an isolated sprinkler equipped with a 4.8 mm nozzle and operating at a pressure of 200 kPa. Sprinkler performance was characterized from photographs of 1,464 drops taken at distances ranging from 1.5 to 12.5 m. It was possible to analyze separately the drops emitted by the main jet and those emitted by the impact arm. The proposed technique does not require specific equipment, although it is labor intensive. ; This research was funded by the Plan Nacional de I+D+i of the Government of Spain, through grant AGL2007-66716-C03. Carlos Bautista received a scholarship from the Agencia Española de Cooperación Internacional (AECI). ; Peer reviewed

Pags.- 4 Tabls.- 9 Figs. Available online 11 June 2014. The definitive version is available at: http://www.sciencedirect.com/science/journal/03783774 ; The simulation of center-pivot performance has been the subject of research efforts since the 1960s. Center-pivot models frequently use empirical equations relating pressure and sprinkler radial application pattern. Individual, stationary water application patterns are overlapped and the resulting water application is mapped in the field. Such models use constant tower angular velocity, neglecting the effect of tower alignment. In this work the discontinuous tower movement has been experimentally characterized and modelled, and a complete model has been developed by using a ballistic model of the center-pivot sprinklers considering nozzle diameter, operating pressure and wind speed. A detailed kinetic analysis of a four-tower commercial center-pivot was performed. Each tower was monitored using a high precision GPS, recording tower positions at high frequency. The experimental center-pivot was equipped with fixed spray plate sprinklers (FSPS). Five experimental center-pivot irrigation events were evaluated using catch-cans. The analysis of tower location data permitted to conclude that two key variables (linear speed and switching angle) showed normal distribution patterns. The center-pivot model was validated with catch-can data. Finally, the simulation tool was used to assess the effect of variable tower alignment quality, center-pivot travel speed and wind conditions on irrigation performance. Comparisons were performed in terms of radial, circular and total irrigation uniformity. Results indicate that the observed tower dynamics had no measurable effect on irrigation uniformity. Tower alignment quality started to be relevant when the switching angle lag was equal to or larger than 2°. In the conditions of this analysis, wind speed showed a clear effect on uniformity. As wind speed increased, uniformity first decreased and then increased. Further research is required to generalize these results to other center-pivot sizes and designs (sprinkler packages). ; This research was funded by the Ministry of Economy and Competitiveness of the Government of Spain through grant AGL2010-21681-C03-01. ; Peer reviewed

37 Pags.- 2 Tabls.- 10 Figs. The definitive version is available at: http://elibrary.asabe.org ; The experimental data used in the paper are OA available (http://hdl.handle.net/10261/127635) ; A variety of techniques have been proposed for sprinkler drop characterization. Two of them, the disdrometer method (D) and the low-speed photographic method (P), have recently been applied in the literature. A statistical method for the improvement of disdrometer measurements (DM) has been proposed to improve D measurements. The aims of this study were: (1) to compare the disdrometer and photographic methods under indoor conditions, (2) to produce a drop characterization data set, (3) to assess the effect of the statistical treatment of disdrometer data, and (4) to gain insight into the relationship between drop variables. The drops resulting from an impact sprinkler operating at 200, 300, and 400 kPa were characterized at distances of 3, 6, 9, and 12 m from the sprinkler. In each method, diameters responded to operating pressure and distance from the sprinkler according to the expected trends. The difference in volumetric diameter estimation between methods P and D amounted to -4% of the average P volumetric diameter. The application of DM to this data set increased the difference in volumetric diameter with method P to 15%. Drop velocity and angle could be measured with method P and showed clear relationships with drop diameter. Finally, regression equations are presented relating the most relevant experimental variables. The disdrometer resulted in fast measurements of drop diameter, while the photographic method provided additional variables but required intense work in the laboratory and particularly in the office. ; This research was funded by the Plan Nacional de I+D+i of the Government of Spain (Grant No. AGL2007‐66716‐ C03). Carlos Bautista‐Capetillo received a scholarship from the Agencia Española de Cooperación Internacional para el Desarrollo (AECID). ; Peer Reviewed