Adaptation of pressurized irrigation networks to new strategies of irrigation management: Energy implications of low discharge and pulsed irrigation

https://doi.org/10.1016/j.agwat.2016.02.023Get rights and content

Highlights

  • Consequences of adopting new on-farm irrigation management strategies on energy consumption and electric costs in a pressurized irrigation network were analyzed.

  • Reductions of emitter discharge and energy consumption or energy cost savings are not inherently related to each other.

  • Pulsed irrigation in the current scenario showed an energy saving potential.

Abstract

This paper analyzes the consequences of adopting new on-farm irrigation management strategies (low discharge rates, long irrigation times and high frequencies) in an existing on-demand and sectorized pressurized irrigation system in eastern Spain. The sectorized behavior of the network was analyzed using two criteria: (i) the operating sectors obtained in a first stage by arranging the hydrants depending on their altitude respecting the pumping station and (ii) the operating sectors obtained by means of an optimization process. The Simulated Annealing combinatorial metaheuristic optimization technique was employed to find the best solution. Random on-demand patterns were generated using a Montecarlo simulation. The hydraulic requirements of the network were analyzed in every scenario by the Epanet 2.0 engine. The effect on energy consumption, power requirements and energy costs was assessed taking into account the electricity tariff billing structure. It was found that reductions in emitter discharge (qe) and Energy consumption (E)-Energy Cost (EC) savings are not inherently related to each other. Certain amounts of E and EC could be saved when the number of sectors and operating time parameters were properly selected. Pulsed irrigation in the current scenario showed an energy saving potential of 10.67, 6.43 and 6.99% for power capacity, E and EC, respectively.

Introduction

In many Mediterranean countries traditional irrigation schemes have been modernized during the last two decades. This updating of the irrigation facilities consisted of substituting ancient open-cannals-based transport, distribution, and surface watering systems by pressurized piping systems (Plusquellec 2009) in an attempt to achieve several advantages: (a) reduce water losses during transport and application, (b) overcome topographic constraints, (c) avoid uncontrolled water withdrawals, and (d) invoice the exact amount of water consumed on each farm (Lamaddalena and Sagardoy, 2000, Daccache et al., 2010a, Daccache et al., 2010b, Daccache et al., 2010c). In addition, pressurized irrigation networks make it possible to implement new and more efficient on-farm irrigation systems, mainly drip and sprinkler irrigation. This entire process has derived in an increase of the water use efficiency but simultaneously it involves a notably increase in energy consumption (IDAE, 2008), especially in sprinkler irrigation. Many studies can be found in the literature aimed at assessing the behavior of pressurized irrigation networks in order to improve their energy consumption (Fernández García et al., 2013, Fernández García et al., 2014, Fernández García et al., 2016, Díaz et al., 2009, García-Prats et al., 2012, González Perea et al., 2014, Jiménez-Bello et al., 2010, Jiménez-Bello et al., 2015, Rodríguez Díaz et al., 2007, Rodríguez Díaz et al., 2012, Tarjuelo et al., 2015). The large number of these studies is an indication of the importance of this issue.

Drip irrigation has been traditionally recommended for row crops, vines and trees (Brouwer et al., 1988) although its many proven advantages has meant that its use has been extended to almost all types of crops. Its most significant advantages include: (i) higher water use efficiency (Daccache et al., 2010a, Daccache et al., 2010b, Daccache et al., 2010c), (ii) lower energy requirements than other pressurized irrigation systems and (iii) higher yields and better quality of harvested crops (Vyrlas and Sakellariou, 2005). The increased use of drip irrigation is seen as one way of improving the sustainability of irrigation systems around the world (Cote et al., 2003). The potential efficiency of drip irrigation is generally accepted to be around 90%, however we should not lose sight of the fact that this value is not an inherent property of the system, but a function of its management (Smith et al., 2010). Discharge rates and irrigation times and frequencies are the most important management-related parameters.

Continuous irrigation (sometimes named microdrip irrigation in the literature) is defined as a drip irrigation system that supplies water at a rate close to that of plant water uptake in order to improve irrigation efficiency and yields and reduce water losses from drainage below the root zone (Assouline, 2002, Assouline et al., 2002). However, soil moisture regimes similar to those resulting from continual low water application rates can be achieved by means of pulsed drip irrigation at higher discharge rates (Phogat et al., 2013). Pulsing involves the application of the same total amount of water and irrigation time but in a phased manner, i.e. fractioned into a series of on–off irrigation cycles.

Searching for the best management system to make the most of drip irrigation, several recent works deal with different management strategies in a combination of continuous and pulsed irrigation (Assouline, 2002, Assouline et al., 2002, Elnesr et al., 2015, Elnesr and Alazba, 2015, Segal et al., 2006, Vyrlas and Sakellariou, 2005, Phogat et al., 2012, Phogat et al., 2013, Skaggs et al., 2010, Elmaloglou and Diamantopoulos, 2007, Cote et al., 2003). In several cases they found enhanced yields, efficiency, salt distribution and fertilizer leaching using low rates, high frequency and pulsed irrigation. In other cases they found no differences between management strategies, but in no case have worse results been reported from continuous or pulsed irrigation. Hence, both these methods are promising fields that should be considered in order to achieve more efficient use of irrigation water, but not only on the farms themselves, since overall efficiency is the product of all the efficiencies obtained from the entire network (storage, conveyance, distribution, application, etc.).

Due to the interaction between the pressurized irrigation network, its pumping station and on-farm irrigation systems (Lamaddalena et al., 2007, Daccache et al., 2010a, Daccache et al., 2010b, Daccache et al., 2010c, González Perea et al., 2014), it could be expected that any change on the irrigation management strategy would have new associated scenarios with different head losses in pipes and requirements for operating time, total discharge and pressure head in the pumping station in comparison to those one of the currently used system. In addition, every new scenario will have other associated energy implications, related not only to energy consumption, but also to the electricity billing structure. These consequences could be expected to be different if the pressurized irrigation network was planned to perform on-demand or sectorized.

Hence, the objective of this work was to analyze the consequences of adopting new strategies of on-farm irrigation management (low discharge rates, large irrigation times and high frequencies) in a pressurized on-demand and sectorized irrigation network in the east of Spain, taking into consideration the interaction all those new strategies with the electricity tariff billing structure.

Section snippets

Discharge calculations of on-demand performance

A lot of pressurized irrigation networks have been scheduled to work on-demand; water is delivered from the network with enough pressure to meet the on-farm irrigation system requirements, and the farmer to decide the duration and frequency of operation. The number of hydrants that operates at the same time is determined using a stochastic process. Divers methods can be found in the literature to determine the network discharge when operates on-demand. We used the Clément’s 1st formula method (

Results and discussion

As can be seen in Table 2, 46 different scenarios were considered to show the effect on energy consumption of new irrigation management strategies (continuous and pulsed irrigation) in pressurized irrigation networks.

Conclusions

In this work forty-six different scenarios were considered to illustrate the effect on energy requirements of new irrigation management strategies (continuous and pulsed irrigation) in pressurized irrigation networks.

Continuous irrigation in networks operating on-demand or sectorized with sectors created without any criteria lead to high energy demands and thus high energy costs. However, significant energy and cost savings can be achieved by employing optimization techniques to organize

Acknowledgements

The study has been partially funded by the IMPADAPT project (CGL2013-48424-C2-1-R) with Spanish MINECO (Ministerio de Economía y Competitividad) and Feder funds.

The authors would like to thank the editor and reviewers for their valuables suggestions.

References (40)

  • S. Assouline

    The effects of microdrip and conventional drip irrigation on water distribution and uptake

    Soil Sci. Soc. Am. J.

    (2002)
  • S. Assouline et al.

    Microdrip irrigation of field crops: effect on yield, water uptake, and drainage in sweet corn

    Soil Sci. Soc. Am. J.

    (2002)
  • C. Brouwer et al.

    Irrigation Water Management: Irrigation Methods. Training Manual No. 5

    (1988)
  • R. Clément
    (1966)
  • C.M. Cote et al.

    Analysis of soil wetting and solute transport in subsurface trickle irrigation

    Irrig. Sci.

    (2003)
  • A. Daccache et al.

    Climate change and the performance of pressurized irrigation water distribution networks under mediterranean conditions: impacts and adaptations

    Outlook Agric.

    (2010)
  • A. Daccache et al.

    On-demand pressurized water distribution system impacts on sprinkler network design and performance

    Irrig. Sci.

    (2010)
  • A. Daccache et al.

    Assessing pressure changes in an on-demand water distribution system on drip irrigation performance-case study in Italy

    J. Irrig. Drain. Eng.

    (2010)
  • M.N. Elnesr et al.

    The effects of three techniques that change the wetting patterns over subsurface drip-irrigated potatoes

    Span. J. Agric. Res.

    (2015)
  • M.N. Elnesr et al.

    Evaluating the effect of three water management techniques on tomato crop

    PLoS One

    (2015)
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