analysis problems, where the hydraulic simulation has to be repeated many times. Among 7 the methods used for hydraulic solvers, the most prominent nowadays is the global gradi-8 ent algorithm (GGA), based on a hybrid node-loop formulation and used by the software 9 package Epanet. Earlier, another method based just on loop flow equations was proposed, 10 which presents the advantage that it leads to a system matrix which is in most cases much 11 smaller than in the GGA method, but has also some disadvantages, mainly a less sparse 12 system matrix, and the fact that introducing some types of valves requires the redefinition 13 of the set of network loops initially defined. 14The contribution of this paper is to present solutions for overcoming the mentioned 15 disadvantages of the method based on loop flow equations. In particular, efficient procedures 16 are shown for selecting the network loops so as to achieve a highly sparse matrix, and methods 17 are presented to incorporate check valves and automatic control valves, while avoiding the 18 need to redefine the loops initially selected.

With the aim of reducing energy consumption and improve water use in pressurised irrigation systems, the methodology for grouping intakes of pressurised irrigation networks into sectors to minimize energy consumption developed by Jimenez Bello et al.(2010a) was modified to allow irrigation intakes to operate the scheduled time according to crop water needs instead of operating in restricted irrigation periods of the same length. Moreover a method was developed to detect the maximum number of intakes that can operate without extra energy in the case the source has enough head to at least feed some of them. These methods were applied to a Mediterranean irrigation system, where the total cropped area was orchards, mainly citrus. In this case study, water was allocated to two different groups of intakes, one fed by gravity and the other one by pumps. A saving of 36.3 % was achieved, by increasing the total volume supplied by gravity, by decreasing the injection pump head and by improving the pump performance. Therefore all intakes operate just the strict irrigation time at the minimum required pressure. Dear Editor:The work we submit for reviewing to Agricultural Water Management is the fourth manuscript of a serial that deals about energy, water and fertilizer management in pressurized irrigation networks. In the previous ones, a methodology to schedule irrigation intakes in pressurized networks minimizing energy consumption was introduced and validated.In the present work, this methodology has been extended to apply just the crop water requirements by allowing to operate irrigation intakes the proper irrigation time. Moreover a new method has been deployed to increase the volume applied by gravity.The methodology has been applied to a real study case that represents a characteristic Mediterranean modernized irrigation district.The authors belong to several research institutes from the Universitat Politècnica de València (UPV), SpainThank you for receiving our work.Best regards.Miguel Angel Jimémez Bello With the aim of reducing energy consumption and improve water use in pressurised irrigation 13 systems, the methodology for grouping intakes of pressurised irrigation networks into sectors 14 to minimize energy consumption developed by Jimenez Bello et al.(2010a) was modified to 15 allow irrigation intakes to operate the scheduled time according to crop water needs instead of 16 operating in restricted irrigation periods of the same length. Moreover a method was 17 developed to detect the maximum number of intakes that can operate without extra energy in 18 the case the source has enough head to at least feed some of them. 19These methods were applied to a Mediterranean irrigation system, where the total cropped 20 area was orchards, mainly citrus. In this case study, water was allocated to two different 21 groups of intakes, one fed by gravity and the other one by pumps. A saving of 36.3 % was 22 achieved, by increasing the total volume supplied by gravity, by decreasing the injection 23 pump head and by...