Increasing Irrigation Efficiency Research Articles

Unfolding the Water Framework Directive Implementation at the River Basin District Scale: An Italian Case Study on Irrigation Measures

Despite that the European Water Framework Directive has attracted scholars’ attention worldwide, research is sparse on how its implementation is carried out for the whole River Basin District (RBD). This paper aims to fill this research gap by studying the implementation of this directive in the Italian Eastern Alps RBD. Based on 21 semi-structured interviews with both public authorities and the stakeholders engaged with implementation, along with a document analysis, we traced the overall implementation process, from planning to implementation, of measures to increase irrigation efficiency. Our interest was on how coordination mechanisms for the entire RBD were established during the main steps of the implementation process. Moreover, we looked at the effects of the Water Framework Directive at the local level, both in terms of changes in irrigation management practices and in terms of stakeholders’ engagement in decision-making processes. We found that, establishing decision-making processes based on a stronger coordination among all the authorities involved was fundamental both in terms of the production of shared decisions and of the participants’ satisfaction with the processes. Moreover, if true participation of stakeholders has to be achieved in the decision-making processes, then the RBD could not be the only scale where participation takes place. Actually, interactions among stakeholders and public authorities, in order to consider local interests in the decision-making processes, could be more effective at the sub-RBD level Ultimately, while cross-administrative coordination can be achieved for the whole RBD through specific coordination mechanisms, public participation should find more appropriate spaces at the sub-RBD level.

Groundwater conditions related to climate change in the semi-arid area of western Iran

The effect of climate change on future groundwater conditions in the Toyserkan basin in western Iran has been studied. In recent years, overexploitation for agricultural activities has led to water-table decline. Groundwater recharge rate predictions in the study area were obtained from the RCP4.5 Scenario of the 5th Assessment Report of the Intergovernmental Panel on Climate Change and HadGEM2 General Circulation Model. Outputs were downscaled with the RegCM4 Regional Climate Model coupled to the Community Land Model version 4.5 (CLM 4.5). RegCM4 model validation and prediction were attempted for 7 years (1999–2005) and 11 years (2015–2025), respectively. Validation results showed that RegCM4 reasonably simulated daily precipitation and monthly temperature and runoff. Firstly, geological, geophysical and hydrogeological data were used and evaluated to develop the conceptual model. Secondly, a 3D numerical model of groundwater flow was developed in order to describe the groundwater regime and predict the effects of water management strategies. Two scenarios were defined for the prediction period. The first scenario assumes that current exploitation rates will be continued, while the second one assumes a 20 percent decrease in pumping due to increased irrigation efficiency. The results showed a water-table rise from 2015 to 2025, which is heightened by increase in irrigation efficiency.

Effects of Irrigation Water Salinity on Soil Properties, N2O Emission and Yield of Spring Maize under Mulched Drip Irrigation

Brackish water has been widely used to irrigate crops to compensate for insufficient freshwater water supply for agricultural use. The goal of this research was to determine an efficient brackish water use method to increase irrigation efficiency and reduce N2O emission. To this end, we conducted a field experiment with four salinity levels of irrigation water (1.1, 2.0, 3.5, and 5.0 g·L−1 with drip irrigation) at Hetao Irrigation District (Inner Mongolia, China) in 2017 and 2018. The results show that irrigation with 3.5–5.0 g·L−1 water salinity increased the soil salinity compared with irrigation using 1.1–2.0 g·L−1 water salinity. The soil water content with 5.0 g·L−1 brackish water irrigation was significantly higher than with 1.1–3.5 g·L−1 water salinity due to the effect of salinity on crop water uptake. The overall soil pH increased with the increase in irrigation water salinity. Saturated soil hydraulic conductivity decreased with the increase in irrigation water salinity. These results indicate that brackish water irrigation aggravates the degree of soil salinization and alkalization. The soil N2O cumulative flux resulting from irrigation with 5.0 g·L−1 water salinity was 51.18–82.86% higher than that resulting from 1.1–3.5 g L−1 water salinity in 2017, and was 32.38–44.79% higher than that resulting from 1.1–2.0 g·L−1 in 2018. Irrigation with brackish water reduced maize yield, and the reduction in yield in 2018 was greater than that in 2017, but irrigation with 2.0 g·L−1 brackish water did not significantly reduce maize yield in 2017. These results suggest that reducing the salinity of irrigation water may effectively reduce soil N2O emission, alleviate the degree of soil salinization, and increase crop yield.

Water consumption, land use and production patterns of rice, wheat and potato in South Asia during 1988–2012

South Asia is home to over one-fifth of the global population where around 276 million people are chronically undernourished. This research analyzed the water consumption, agricultural land use and production patterns of three major cultivated crops in South Asia for the period 1988–2012, namely rice, wheat and potato. Data have been collected from AQUASTAT and FAOSTAT databases of the Food and Agriculture Organization. Results reveal that the majority of South Asian countries have managed to increase food production through intensive groundwater-based irrigation during the non-monsoon period. Food production in South Asia largely depends on high water-consuming crops such as rice and wheat. In recent years, potato-harvested area and volume of production both increased substantially compared to 1990s. However, to meet the demand of a growing population with finite land and water resources, South Asian countries should take a number of steps including promoting the cultivation of less water-consuming crops through diversification of cropping pattern, reducing high dependency on groundwater, increasing irrigation efficiencies and conjunctive use of water. These steps would help South Asian countries to promote sustainable agriculture in line with goal 2 of the Sustainable Development Goals.

Missing in action: possible effects of water recovery on stream and river flows in the Murray–Darling Basin, Australia

ABSTRACTWe use published water balance data from irrigated cropping to show that water entitlements acquired for environmental purposes through water infrastructure subsidies in the Murray–Darling Basin, Australia, have resulted in smaller increases in net stream and river flows than is estimated by the Australian Government, and may even have reduced net stream and river flows. Two key policy implications arising from our results are: (1) subsidies to improve irrigation efficiency so as to increase stream and river flows must employ water accounting so that the effects on return flows are known and the volume of water extracted for irrigation is adjusted to achieve desired stream and river flows; and (2) if the net increases in stream and river flows in the MDB are much less than estimated by the Australian Government, water infrastructure subsidies to increase irrigation efficiency may have compromised the delivery of key objects of the Water Act (2007).

The limits to participation: branch-canal water user associations in the Egyptian Delta

ABSTRACTEgypt has valuable experience with water user associations in irrigated agriculture. Internationally funded irrigation improvement projects aiming to increase irrigation efficiency have introduced water user associations at the branch-canal level alongside improvements to the infrastructure in the Central Delta of Egypt. In this article we review those water management practices in which these associations are expected to participate. Our main finding is that their role in these areas is minimal and that they are generally weak organizations. Either such organizations should be genuinely strengthened legally and politically, and given real responsibilities and resources, or the entire idea of participation should be abandoned.

Economics of Water Recovery in the Murray-Darling Basin, Australia

We review recent water reforms and the consequences of water recovery intended to increase stream flows in the Murray-Darling Basin (MDB), Australia. The MDB provides a natural experiment of water recovery for the environment that includes ( a) the voluntary buy-back of water rights from willing sellers and ( b) the subsidization of irrigation infrastructure. We find that ( a) the actual increase in the volumes of water in terms of stream flows is much less than claimed by the Australian government; ( b) subsidies to increase irrigation efficiency have reduced stream and groundwater return flows; ( c) buy-backs are much more cost effective than subsidies; ( d) many of the gains from water recovery have accrued as private benefits to irrigators; and ( e) more than a decade after water recovery began, there is no observable basin-wide relationship between volumes of water recovered and flows at the mouth of the River Murray.

Sustainability assessment of restoration plans under climate change by using system dynamics: application on Urmia Lake, Iran

Abstract During the last decade, Urmia Lake has lost most of its surface area. As a result, finding management practices to restore the sustainable ecological status of Urmia Lake, the world's second largest hyper-saline lake, is imperative. In this study, the sustainability of different plans under climate change was assessed using system dynamics. The plans were evaluated with respect to sustainability criteria including reliability, resiliency, and vulnerability measures. According to the results due to different management practices, on average, water consumption should be reduced by at least 30% to restore the lake. The results revealed that only hybrid plans which incorporate multiple management practices, instead of focusing on just one approach, can be influential. Among the hybrid plans, that of increasing irrigation efficiency, reducing cultivated area, changing crop pattern, and inter-basin water transfer was identified as the most sustainable plan. About eight years after applying this plan, the lake will achieve its ecological level and will remain sustainable. Considering comprehensive factors, the proposed model can help watershed managers to take the necessary measures to restore this vital ecosystem. The results of this study can be applied to water resources systems with the same problem, especially those in semi-arid regions with multidisciplinary aspects.

Modelling of Water Flow and Nitrate Dynamics Through Partially Saturated Porous Media in Laboratory Condition using Hydrus-2D

Due to the reducing availability of water resources and the growing competition for water between residential, industrial, and agricultural users, increasing irrigation efficiency, by several methods like drip irrigation, is a demanding concern for agricultural experts. The understanding of the water and contaminants flow through the subsurface is needed for the sustainable irrigation water management, pollution assessment, remediation, and groundwater recharge. In this study, the Windows-based computer software package HYDRUS-2D, which numerically simulates water and solute movement in two-dimensional, variably-saturated porous media, was used to evaluate the distribution of water and Nitrate in the sand tank. The laboratory and simulation experiments were conducted to evaluate the role of drainage, recharge flux, and infiltration on subsurface flow condition and subsequently, on nitrate movement in the subsurface. The water flow in the unsaturated zone was model by Richards’ equation, which was highly nonlinear and its parameters were largely dependent on the moisture content and pressure head of the partially saturated zone. Following different cases to be considered to evaluate- a) applying drainage and recharge flux to study domains, b) transient infiltration in a vertical soil column and c) subsequently, nitrate movement in a 2D sand tank setup. A single porosity model was used for the simulation water and nitrate flow in the study domain. The results indicate the transient water table position decreases as the time increase significantly by applying drainage flux at the bottom. Similarly, the water table positions in study domains increasing in the domain by applying recharge flux. Likewise, the water flow profile shows the decreasing water table elevation with increasing water content in the vertical domain. Furthermore, the nitrate transport dynamics was dominated by advective flux and highly affected by the recharge flux in the vertical direction. The findings of the study help to enhance the understanding of the sustainable soil-water resources management and agricultural practices.

Application of Fuzzy Technique for Order-Preference by Similarity to Ideal Solution (FTOPSIS) to Prioritize Water Resource Development Economic Scenarios in Pishin Catchment

Water is a basic demand of sustainable development in most regions of the world. The non-uniform temporal and spatial distribution of water resources will lead to water shortage in arid and semi-arid areas. Pishin catchment is one of the most important catchments in South-East Iran. The basin had been faced with consecutive droughts in recent years. On the other hand, water resources development projects anticipated and necessary in this catchment. Hence, the need for a study to prioritize different scenarios and their effects on the catchment should be considered to overcome these dry periods. The main objective of the present study is to predict water development projects in the study area. Due to the multiplicity of projects and high cost of them, the concurrent execution priority implementation of these projects is considered as an important factor. Fuzzy multiple attribute decision making is a suitable method for comparison, selection and prioritization of the different options taking into account different criteria. Hence, in this study, the effects of the water development projects are predicted using Water Evaluation and Planning System (WEAP) model. The projects according to the economic criteria are evaluated and prioritized with Fuzzy TOPSIS. Six water development projects and criteria including five economic indexes are considered. Based on the results, according to the investigated indicators, increasing irrigation efficiency in agricultural sector and reducing evaporation from the reservoir scenarios have top priority.

Formation and prevention of biofilm and mineral precipitate clogging in drip irrigation systems applying treated wastewater

Pressure-irrigation systems and, in particular, micro-irrigation provide an effective methodology for increasing irrigation efficiency. However, emitter clogging is a major problem in micro-irrigation systems, especially under irrigation with treated wastewater (TWW). Currently, farmers treat their irrigation system by periodical application of solutions of chemicals or washing the lateral lines. The aim of this study was to characterize treatments for the prevention of clogging in drip irrigation systems utilizing different qualities of TWW (secondary and tertiary TWW). A model system was designed and assembled to compare the flow rate (FR), fouling accumulation and fouling composition in laterals and drippers subjected to different treatments. Under irrigation with secondary TWW, control treatment function decreased rapidly while chemical treatment prolonged proper function of the drippers by maintaining a normal FR and coefficient of variation (CV). Wash treatment improved to some extent the irrigation function. Under irrigation with tertiary TWW the function of all treatments was significantly better than that of the secondary treatments. The total suspended solids level was found to be a significant factor in the mechanism of clogging formation according to biofouling development. The deposit chemical characterization could shed light on the mode of growth mechanism and properties of the biofouling. In general, oxidation treatments using hydrogen peroxide or hypochlorite acid were found to eliminate biofouling and in accordance also prevented clogging.

The Contribution of Improvements in Irrigation Efficiency to Environmental Flows

Increasing irrigation efficiency is often assumed to be a means of saving water and a route to increasing irrigated agricultural production or making water available for other purposes, such as communities, industry or ecosystems. There is a growing body of literature arguing that increasing irrigation efficiency does not reduce consumptive water use in agriculture, implying that no additional water is made available for supporting environmental flows. However, understanding the implications of changes in irrigation efficiency for environmental flows requires assessment at temporal and spatial scales between the daily to seasonal field level analysis of advocates for increasing irrigation efficiency to save water, and the annual basin scale view of some of its critics. When investigated at these intermediate temporal and spatial scales, there may be potential for improvements in irrigation efficiency to mitigate the effects of irrigation on flow timings to an ecologically meaningful extent. In situations where this is possible, in advance of implementing irrigation efficiency programmes, overall water consumption must be limited by an effective water allocation regime that explicitly recognises environmental flow needs in order to prevent expansion or intensification of irrigated agriculture. This paper sets out some of the key issues that practitioners working on environmental flows should consider in order to assess whether or not interventions to increase irrigation efficiency can support environmental flow objectives.

Impacts of irrigation efficiency improvement on water use, water consumption and response to water price at field level

Increasing irrigation efficiency has been suggested as a solution in water scarce areas but its potential rebound effect (increased ex-post water consumption) is receiving growing attention; paradoxically, although improved irrigation efficiency may reduce water use, it may also increase water consumption. This paper presents a microeconomic analytical approach to assess the effects of water-saving investments and the resulting irrigation efficiency on water use and consumption at field level. Moreover, it analyses the relationship between irrigation efficiency, water demand and water pricing. Findings show that improving efficiency would significantly reduce water use, though the impact on water consumption would be negligible even if there is a radical increase in water cost. Thus, the potential rebound effect would not be related to irrigation efficiency, but rather to other factors such as irrigated area expansion, crop-mix changes, and market forces, which are out of the scope of this study.

Performance of methods for estimation of table beet water requirement in Alagoas

ABSTRACT Optimization of water use in agriculture is fundamental, particularly in regions where water scarcity is intense, requiring the adoption of technologies that promote increased irrigation efficiency. The objective of this study was to evaluate evapotranspiration models and to estimate the crop coefficients of beet grown in a drainage lysimeter in the Agreste region of Alagoas. The experiment was conducted at the Campus of the Federal University of Alagoas - UFAL, in the municipality of Arapiraca, AL, between March and April 2014. Crop evapotranspiration (ETc) was estimated in drainage lysimeters and reference evapotranspiration (ETo) by Penman-Monteith-FAO 56 and Hargreaves-Samani methods. The Hargreaves-Samani method presented a good performance index for ETo estimation compared with the Penman-Monteith-FAO method, indicating that it is adequate for the study area. Beet ETc showed a cumulative demand of 202.11 mm for a cumulative reference evapotranspiration of 152.00 mm. Kc values determined using the Penman-Monteith-FAO 56 and Hargreaves-Samani methods were overestimated, in comparison to the Kc values of the FAO-56 standard method. With the obtained results, it is possible to correct the equations of the methods for the region, allowing for adequate irrigation management.

Assessing land leveling needs and performance with unmanned aerial system

Land leveling is the initial step for increasing irrigation efficiencies in surface irrigation systems. The objective of this paper was to evaluate potential utilization of an unmanned aerial system (UAS) equipped with a digital camera to map ground elevations of a grower’s field and compare them with field measurements. A secondary objective was to use UAS data to obtain a digital terrain model before and after land leveling. UAS data were used to generate orthomosaic images and three-dimensional (3-D) point cloud data by applying the structure for motion algorithm to the images. Ground control points (GCPs) were established around the study area, and they were surveyed using a survey grade dual-frequency GPS unit for accurate georeferencing of the geospatial data products. A digital surface model (DSM) was then generated from the 3-D point cloud data before and after laser leveling to determine the topography before and after the leveling. The UAS-derived DSM was compared with terrain elevation measurements acquired from land surveying equipment for validation. Although 0.3% error or root mean square error of 0.11 m was observed between UAS derived and ground measured ground elevation data, the results indicated that UAS could be an efficient method for determining terrain elevation with an acceptable accuracy when there are no plants on the ground, and it can be used to assess the performance of a land leveling project.

Drivers of Potential Recharge from Irrigated Agroecosystems in the Wisconsin Central Sands

Core Ideas Groundwater in humid regions should be managed for services, not depletion. Climate variability can be a greater driver of potential recharge than crop type. Soil texture can be a significant driver of point‐based potential recharge estimates. Crop phenology may not be predictive of point‐based potential recharge estimates. The expansion of irrigated agriculture on landscapes underlain by coarse‐grained, glacial aquifers in Wisconsin, Minnesota, and Michigan changes the timing and magnitude of groundwater recharge. Water managers require improved estimates of groundwater recharge to manage pumping impacts on groundwater‐fed streams, lakes, and wetlands. We implemented a network of 25 passive capillary lysimeters to infer potential groundwater recharge and evapotranspiration (ET) from irrigated potato (Solanum tuberosum L.), sweet corn and field corn (Zea mays L.), and pea (Pisum sativum L.)–pearl millet [Pennisetum glaucum (L.) R. Br.] rotations in the Wisconsin Central Sands (WCS) from June through November of 2013 to 2016. We found that interannual climate variability, subtle differences in soil texture, and cropping system type drove potential recharge to varying degrees during the summer and fall seasons. Relatively finer soil texture was positively correlated to point estimates of potential recharge. This correlation was the strongest following large precipitation events. June to November cumulative potential recharge for 2013 to 2016 averaged 71 ± 235 mm across all lysimeters. Our findings suggest that aquifer depletion will be an episodic process that leaves surface waters most vulnerable to pumping and recharge impacts during and following drier years in the WCS. Differences among cropping systems were most pronounced under average precipitation conditions, which facilitated potential groundwater losses under field corn and pea–pearl millet rotations and potential groundwater gains under potato rotations. We conclude that regional water management strategies could be effective in buffering against the interannual climate variability of recharge, while localized management strategies could increase irrigation efficiency by targeting crop and soil textural drivers.

Life cycle environmental impacts of bioethanol production from sugarcane molasses in Iran.

In recent years, bioethanol from sugarcane molasses has been produced on an industrial scale in Iran. The aim of this study was to evaluate molasses-based bioethanol production from an environmental point of view. Data were collected from Debel Khazai agro-industry situated in southern region of Iran by using face-to-face interviews and annual statistics of 2010 to 2016 (6-year life cycle of sugarcane cultivation). Ten impact categories including abiotic depletion (AD), acidification (AC), eutrophication (EP), global warming potential (GWP), ozone layer depletion (OLD), human toxicity (HT), freshwater aquatic ecotoxicity (FE), marine aquatic ecotoxicity (ME), terrestrial ecotoxicity (TE), and photochemical oxidation (PO) were selected based on CML methodology. Inventory data for production of the inputs were taken from Ecoinvent, BUWAL 250, and IDMAT 2001 databases. The results revealed that in sugarcane cultivation process, electricity and trash burning were the most important contributors to all impact categories except OLD and TE. In industrial phase, natural gas had the highest contribution to the most impact categories. Greenhouse gas (GHG) emission for production of 1000L molasses-based bioethanol was 1322.78kg CO2eq. By comparing total GHG emissions from 1000L bioethanol to gasoline, the net avoided GHG emissions came out at 503.17kg CO2eq. According to results, it is clear that with increasing irrigation efficiency and improving performance of heating systems in industrial phase, environmental burdens would be significantly reduced.

Improving chemical and hydro-physical properties of semi-arid soils using different magnitudes of crumb rubber

PurposeIran is located on the desertification strip where it has faced water shortage and poor quality soils. So it is necessary to improve the soil structure and increase irrigation efficiency. In this context, the use of industrial wastes can increase soil’s organic matter and improve its structure, also amend environmental problems related to disposal of industrial wastes. The objective of this study was to survey the effect of crumb rubber (CR) application as soil amendment on soil water retention curve indices, soil aggregate stability and soil micronutrients.MethodsIn this study, different amounts of CR (0, 0.12, 0.24, 0.36 and 0.48 g) were added to every kg of the two different soil textures (loamy sand and silty clay). Pots were kept at FC moisture conditions for 6 months. At the end of incubation time, the different soil micronutrient availability, soil structural stability and soil hydraulic properties were measured.ResultsThe results showed that application of CR as soil amendment had significant effects (p < 0.001) on increasing soil organic matter content and soil micronutrient availability including Zn and Fe. Adding CR particles by reducing the aggregate fractal dimension, soil penetration resistance and bulk density, improves soil structure in both types of soil. The results also demonstrated that the use of CR particles can improve water holding capacity in sandy soil and increased plant available water content and air capacity in clay soil (p < 0.001).ConclusionsAccording to our results adding CR particles can be considered as a low-cost solution in order to improve the hydro-physical and chemical properties of soils in these areas.

Field assessment of surge and continuous furrow irrigation methods in relation to tillage systems

Abstract Surge flow irrigation is one of the irrigation techniques for controlling furrow irrigation. The aim of this study was to investigate the effect of surge furrow irrigation on water management compared with continuous irrigation for different tillage systems. An experimental field was treated with various tillage systems (mouldboard plough, chisel plough and rotary plough) and water irrigation application methods (continuous flow, control) in which irrigation water was applied continuously, and surge flow (3-surges, 4-surges and 5-surges) in which irrigation water was applied intermittently until it reached the tail end of the furrow. The results showed that water savings obtained using the surge technique were 18.58, 11.84 and 18.93% lower water use than with continuous flow, for the mouldboard, chisel and rotary ploughs, respectively. The 3-surges treatment with the rotary plough reduced the advance time by 25.36% from that for continuous irrigation. The 4-surges treatment with the mouldboard plough had the highest water application efficiency (88.13%). The 3-surges treatment with the rotary plough had the highest distribution uniformity (85.01%). The rotary plough did not cause as much soil aeration around the root system as the other tillage systems. The field research provided information about surge flow, aimed at reducing advance times and increasing irrigation efficiency.

Prediction of Groundwater Dynamics for Sustainable Water Resource Management in Bogra District, Northwest Bangladesh

The green revolution in the northwest region of Bangladesh over the past three decades has based on groundwater irrigation. For sustainable agricultural accretion, groundwater dynamics play a vital role in this region. In this study, the groundwater level dynamics have been analyzed with a model named “MAKESENS” and with geographical information systems (GIS). The study indicates that, in most of the wells, the water table (WT) depth and the rainfall intensity are declining slowly. The prediction of WT depth during the period of 2020, 2040, and 2060 indicate that, in some cases, the WT depth will approximately double by the year 2060, considering the present declining trend. This result suggests that, for the sustainable management of groundwater, necessary measures should be adopted to avoid or reduce the severe ecological, social, and economic impacts of groundwater mining. Moreover, crop diversification, conservation techniques, increasing irrigation efficiency, rainwater harvesting, etc. can be adopted to avoid groundwater declination and consequently to enhance the sustainable use of groundwater resources in the area.