Increasing Irrigation Efficiency Research Articles

Delivering global water security: Embedding water justice as a response to increased irrigation efficiency

AbstractIncreasingly, irrigation infrastructure upgrades have been regarded in global policy as a solution for both water scarcity and low agricultural productivity. However, these technical “fixes” may ultimately prove to be dangerous shortcuts that do little to address the concerns of irrigators, Indigenous People, environmental groups, and local communities about water scarcity, access, security, and sustainability. In the absence of transparent and rigorous governance safeguards, irrigation efficiency upgrades can result in higher water consumption, demand, and ultimately, increased water scarcity. Upgraded irrigation systems also tend to capture return flows and redistribute them to “high value” consumptive water uses, potentially displacing other users and uses, including Indigenous Peoples. In this article, we critique current approaches to governing irrigation efficiency, using a water justice lens to identify four key insights and their implications for governance. We propose new governance pathways and options that take into consideration hydrological realities and the full range of water demands and needs.This article is categorized under: Human Water > Water Governance Water and Life > Conservation, Management, and Awareness Human Water > Water as Imagined and Represented

Irrigation management zone strategies impact assessment on potential crop yield, water and energy savings

In irrigated agriculture, soil spatial variability is a primary factor for low irrigation efficiency. In regions such as the Brazilian Cerrado, where there is a continuous growth of irrigated agriculture and limited water supplies, it is important to seek alternatives to reach an efficient and sustainable irrigated agriculture. In this context, precision irrigation has great potential. Better strategies must be established, especially for center pivot irrigation conditions. Irrigation considering management zones is a promising option; however, criteria must be set to delimitate management zones and evaluate irrigation performance in such situations. This study aims to assess the impact of the use of management zones on irrigation performance. Therefore, two center pivots, PivoBHBV and PivoBHALPA, with distinct soil water physical traits, were evaluated. Two management zones strategies were considered to carry out the simulations. One of the strategies was based on regions in the format of square grids with areas of 25, 100 and 225 m2. In the other strategy, the unsupervised grouping algorithm Fuzzy C-Means was used to create management zones. The irrigation performed on those management zones was assessed by comparing their performance with the irrigation conducted in the grid areas. The irrigation management zones were delimited based on the interpolated maps of soil available water capacity (AWC), and the management was conducted individually for each zone. The simulations were made through a model developed with the Python language. The results indicate similarity between the irrigation with management zones and the grid irrigation, as it did not significantly increase water and energy demands or reduce soybean yield. Precision irrigation practiced management zones increased irrigation efficiency, reducing the effect of soil spatial variability. The total irrigation depth applied was, on average, 1.47 % lower than the irrigation by grids. Comparing the grid and the management zones irrigations, water and energy savings potential and the average yield increase potential were 1.85 %, 1.75 %, and 0.41 %.

Critical Role of Irrigation Efficiency for Cropland Expansion in Western China Arid Agroecosystems

AbstractThe rapid expansion of desert croplands in the Tarim River Basin, which depend heavily on irrigation with meltwater, has coincided with increases in snow and glacier melt in the high mountains of Asia during the past decades. Meanwhile, there have been intensive investments in modern irrigation technology aimed at enhancing water use efficiency. The importance of meltwater in mountain front agroecosystems has been widely acknowledged, but it is not clear how important this meltwater versus increased irrigation efficiency (IRE) has been for the rapid cropland expansion in the Tarim River Basin. Here we investigate changes in water supply and demand of the meltwater‐irrigated cropland bordering the Taklamakan Desert based on multiple remotely sensed and ground‐based observation datasets, and we evaluate the contributions of improved IRE to cropland expansion. We find that cropland has increased by 58% between 1990 and 2015. Net streamflow to the region increased by +10% over the same period, but the rate of increase was slower after 2000. This deceleration contrasts with the growing irrigation demand (IRD) imposed by dramatic cropland expansion. At the same time, IRE increased by 73% from 1990 to 2015, providing 18.5 billion m3irrigation water savings, which offset the increased IRD. With the adoption of more efficient irrigation, crop water stress due to continuous agricultural expansion in the Tarim River Basin declined significantly, making the dependence of agricultural production on runoff from glacier and snow meltwater less than would otherwise be expected.

Rebound Effects in Irrigated Agriculture in Uzbekistan: A Stakeholder-Based Assessment

There is wide consensus among scholars and practitioners that improved irrigation technologies increase farm productivity and improve resource use efficiency. However, there is also growing empirical evidence that efficiency improvements in irrigation water use may create rebound effects, i.e., they may trigger changes in farmers’ behavior that partly or fully offset the technical water savings expected under ceteris paribus conditions. In extreme cases, total water consumption may even increase. We studied the impacts of introducing water-saving irrigation technologies in Uzbekistan and used structured stakeholder interviews for an expert-based assessment of potential rebound effects. Our findings contribute to the understanding of impacts of technological and institutional responses to environmental and economic pressures in sustaining water resources. The study demonstrates that although the objective of increasing irrigation efficiency may be achieved, the actual water savings under Uzbek conditions are likely to be reduced due to rebound effects. Unless there are effective policy interventions, we expect rebound effects through an increase in water supply for crops that compensates for current shortages of irrigation water availability, an increase in irrigated area, a switch to more water-intensive crops, and overall economic growth. The findings of this paper provide a reference point for estimating the water-saving potential and for evaluating and adapting policies.

Building Type, Housing Density, and Water Use: Denver Water Data and Agent‐Based Simulations

AbstractThis study examined simulated changes in total (and outdoor) water demand with increased dwelling units per unit area (DUUA) for seven building types (BTs) in the Denver Water service area. We utilized the Denver Water Demand Model — a spreadsheet tool that uses inputs such as BT, population, household size, number of units, etc. — to develop an “agent‐based” simulator to permit scenario analyses of future water use for different mixes of BTs. We examined household “movement” for new residents from lower density to higher density classifications. Increased residential density can be achieved through multiple pathways. For instance, a family could move from a large single‐family (LSF) unit to a single‐family home with a smaller lot footprint (SSF). Or, a family could move into a multi‐family housing development from a SSF. Our results suggest uneven, nonlinear efficiency gains in water use with increased density, depending on the specific BT movements. Simulation outputs indicate that the greatest gains in water savings per unit change in DUUA can be achieved with short movements over the lowest density classes (e.g., LSF to a SSF). In addition, results suggest that increasing irrigation efficiency (less water applied per unit area irrigated) may decrease total residential water demand by 5% to 25% over baseline; efficiency of irrigation may prove to be as effective, if not more, at reducing residential water demand as increasing housing density.

Development of mini-lysimeter system for use in irrigation automation of container-grown crops

Development of more efficient and sustainable irrigation technology is critical to maintain horticultural production in a water scarce future. Sensor controlled irrigation is an emerging technology that has the potential to increase irrigation efficiency and reduce overwatering by using real-time data on container water status to control the timing and volume of irrigation events. This project presents a novel irrigation control system using lysimetry. We develop small scale lysimeters, referred to as mini-lysimeter, which provide a direct measure of actual evapotranspiration (ET) via a change in mass of containerized crops. As such, mini-lysimeter sensors have the potential to be an effective instrument for automatic irrigation scheduling. This paper presents the mini-lysimeter controlled irrigation system design in detail, including the mini-lysimeter sensors, data logger and control system configuration, and the hardware needed to integrate the control system into existing irrigation infrastructure. A proof of concept study is presented where mini-lysimeter (ML) controlled irrigation is compared to a traditional timer-based irrigation schedule. Results show that the ML controlled irrigation system can produce plants of equal size to traditional irrigation methods while using 26% less water on average. The outcome of this study indicates that the hardware presented here is reliable and robust enough to produce quality plants in a real nursery production setting, and this technology provides a novel approach to improving water efficiency in container nurseries.

Ресурсозберігаючі елементи технології краплинного зрошення інтенсивних насаджень черешні (Cerasus avium Moench.) в умовах Південного Степу України

The research is dedicated to establishing the parameters of the micro-irrigation regime in cherry orchards in the south of Ukraine using meteorological indicators and the amount of evapotranspiration as a basis for further determining the optimal irrigation regime. Field experiments were conducted in 2019-2020 on the lands of the M.F. Sydorenko Melitopol Research Station of Horticulture of the Institute of Horticulture, NAAS of Ukrain. In the investigation the following variants of the experiment are provided: a control variant – natural moistening, variants with the use of irrigation at pre-irrigation soil moisture level (PISML) of 70 % of least soil moisture (LSM) at different moisture layers of 0.4 m, 0.6 m, and 0.8 m, and variants with deficient irrigation at 100 %, 75 % and 50 % evapotranspiration compensation (ET0). As a result of research, it was established that the compensation of evapotranspiration (ET0) at the level of 75 % determines the maintenance of soil moisture in a layer of 0.6 m not lower than 67-70 % HB. The deviations of irrigation rates between this option and the PISML of 70 % LSM (0.6 m) do not exceed 6 % due to the increase in irrigation efficiency. Maintenance of 70 % LSM in the 0.4 m layer and at 50 % ET0 leads to a weakening of cherry production processes, which indicates the inconsistency of such a moisture regime with the biological requirements of cherry culture. The advantages of the irrigation regime for PISML 70 % LSM in a layer of 0.8 cm and for 100 % ET0 in terms of influence on cherry production processes were not revealed. At the same time, water consumption increases by 28-33 % due to a decrease in irrigation efficiency relative to compliance with this moisture regime in a layer of 0.6 m. The best indicators of irrigation efficiency were in the options of 75 % ET0 - 2.8 kg/m3 and with PISML 70 % LSM (0.6 m) – 2.2 kg/m3. Such data indicate the expediency of using the calculation method for determining the irrigation regime of cherry trees, as an alternative to the thermostatic-weight method.

Comparison of an Innovative Mobile Strip Irrigation System with Full-Area Sprinkler Watering

Highlights Innovative stripwise irrigation directs water only to ridge crests, not furrows. Mobile strip irrigation saved 51% of the carrot water requirements. The uniformity coefficient of the irrigation above the ridges was high. No significant differences in the carrot yield were verified between the irrigation systems. The water use efficiency was higher for the mobile strip irrigation system. ABSTRACT. Irrigation plays an important role in agriculture in temperate regions because of the reduction in rainfall frequency during the spring and summer months along with the increase in average temperature and evapotranspiration. To increase irrigation efficiency, we developed an innovative mobile strip irrigation system for ridge culture. The objective of this pilot study was to compare the new technology with a standard full-area sprinkler system and analyze the yield, flow rate, applied irrigation on the ridges, and variability of the irrigation depths expressed by the Christiansen uniformity coefficient (CUC) and distribution uniformity coefficient (CUD). The experimental design applied the two treatments to carrots grown on eight ridges covering an area of 210 m2. The experiment was conducted at the University of Kassel, Witzenhausen, Germany. The results showed a flow rate ranging from 54.7 to 72.7 l h–1. Good CUC (89%) and excellent CUD (82%) were obtained for the mobile irrigation system, indicating low variability of irrigation depths. The water content in the ridge crest increased to field capacity after irrigation, with a moderate coefficient of variation (14%) among the measurements. In addition, water use reduction with respect to the standard irrigation system of 51% during the treatments, or 29% considering the entire experiment time, was observed, and no significant differences in the total fresh yield between the irrigation systems were verified. Because only a single sprinkler irrigation system with an irrigation efficiency of 80% was used, care must be taken when extrapolating the findings of the present study. High irrigation efficiency sprinkler irrigation systems with multiple sprinklers, which reduce the sprinkler irrigation amount, can be considered in future studies to confirm the increased water usage efficiency of the mobile strip irrigation system. Keywords: Carrots cultivation, Irrigation, Ridge agriculture, Water content, Water distribution, Water saving.

The Water-Energy-Food-Ecosystem Nexus in the Mediterranean: Current Issues and Future Challenges

The Mediterranean is an area where the balance between water demand and abstractions vs. water availability is often under stress already, as demonstrated here with the Water Exploitation Index. In this work, model estimates on how different proposed measures for water resources management would affect different indicators. After a review of the current water resources status in the Mediterranean and the definition of indicators used in this study, aspects interlinked with water in the Water-Energy-Food-Ecosystems Nexus are briefly discussed, focusing on problems linked with water scarcity and depletion of groundwater resources as well as with climate change projections. Subsequently, the proposed measures for water efficiency are detailed—irrigation efficiency, urban water efficiency, water reuse and desalination—that might be effective to reduce the growing water scarcity problems in the Mediterranean. Their effects that result from the LISFLOOD model, show that wastewater reuse, desalination and water supply leakage reduction lead to decreased abstractions, but do not affect net water consumption. Increased irrigation efficiency does decrease consumption and reduces abstractions as well. We deduct however that the current envisaged water efficiency measures might not be sufficient to keep up with the pace of diminishing water availability due to climate change. More ambition is needed on water efficiency in the Mediterranean to keep water scarcity at bay.

Irrigation subsidy policy in Chile: lessons from the allocation, uneven distribution and water resources implications

ABSTRACT Globally irrigation subsidies are utilized to boost modernization and increase irrigation efficiency. This paper examines the effects of the irrigation subsidy programme in Chile by reviewing 32 years of allocations and exploring the drivers and consequences of the subsidy programme with a clear market approach based on competition and a state risk-free strategy. Our analysis reveals that, despite the flexibility in targeting, the results indicate an uneven allocation to smallholders’ detriment, a state inability to identify farmers’ needs, market concentration and a bias towards agricultural expansion. As long as the programme remains unaltered, it will threaten agriculture and water resources’ sustainability.

Fossil water: Last resort to resolve long-standing water scarcity?

Sistan is a drought-affected region in the southeast of Iran, dependent on the variable surface water inflow from the Helmand River basin in Afghanistan. The river flow has recently experienced sharp annual fluctuations in Afghanistan, resulting in a collapse of the agriculture and ecosystem in Sistan. Therefore, the authorities have recently decided to rely on non-renewable groundwater (fossil water aquifers) resources to support the current developments in Sistan. The current study aims to assess the adequacy of fossil water aquifers to back the water demand in scarcity. A system dynamics model for the Sistan Water Resources System (SWRS) is developed to analyze the complicated water management system in the basin, which considers major hydrological, socioeconomic, agricultural, and, specifically, environmental aspects. The results show that the water resources in Sistan are incredibly unreliable and vulnerable due to their dependence on the surface water inflow from Afghanistan. Fossil aquifer withdrawal can address the current water problems in Sistan. However, fossil water over withdrawal without considering the critical level of aquifers can eventually lead the project to fail. Unmanaged use of fossil aquifers in Sistan has the characteristics of a "Limits to Growth Archetype" system, with negative and dangerous effects in the long run. In the environmental subsystem, meeting the minimum environmental demand is demonstrated as the effective way to stabilize the soil of the lake and considerably reduce dusty days. Further, fossil aquifer exploitation and demand management by increasing irrigation efficiency and reducing wastage of reservoirs have a great impact on the sustainability of the agricultural sector.

Enhancing the sustainability of Mediterranean olive groves through adaptation measures to climate change using modelling and response surfaces

Some adaptation measures in response to the severe impacts of climate change on Mediterranean olive orchards were evaluated under a wide range of weather conditions. For this task, a decision support system for improving resources management by the integration of the AdaptaOlive simulation model, perturbed climate and impact and adaptation response surfaces for the model output analysis was developed. Thus, the introduction of irrigation (considering different irrigation strategies such as full demand, regulated deficit irrigation or irrigation support), the implementation of cultivars with lower chilling requirements, the modification of orchard density and an increase in irrigation efficiency were evaluated under current and future weather conditions.Optimal sustainable and environmentally friendly adaptation measures varied depending on the local weather conditions. Thus, the introduction of irrigation provided excellent results under dry and cool winter weather conditions. Cultivars with low chilling requirements reduced flowering failure associated with the lack of chill accumulation and registered optimal performance under mild winter conditions. This adaptation measure played a critical role under these weather conditions, even more so than measures focused on preventing water stress as irrigation. Finally, increasing orchard density was appropriate in non-water-limited areas with cool winter conditions.This study confirms the great importance of integrating crop modelling and tools for model output analysis into the assessment of site-specific adaptation measures to climate change, in order to ensure the sustainability of Mediterranean agricultural systems under semi-arid conditions.

Integral analysis of environmental and economic performance of combined agricultural intensification & bioenergy production in the Orinoquia region

Agricultural intensification is a key strategy to help meet increasing demand for food and bioenergy. It has the potential to reduce direct and indirect land use change (LUC) and associated environmental impacts while contributing to a favorable economic performance of the agriculture sector. We conduct an integral analysis of environmental and economic impacts of LUC from projected agricultural intensification and bioenergy production in the Orinoquia region in 2030. We compare three agricultural intensification scenarios (low, medium, high) and a reference scenario, which assumes a business-as-usual development of agricultural production. The results show that with current inefficient management or with only very little intensification between 26% and 93% of the existing natural vegetation areas will be converted to agricultural land to meet increasing food demand. This results in the loss of biodiversity by 53% and increased water consumption by 111%. In the medium and high scenarios, the intensification allows meeting increased food demand within current agricultural lands and even generating surplus land which can be used to produce bioenergy crops. This results in the reduction of biodiversity loss by 8–13% with medium and high levels of intensification compared to the situation in 2018. Also, a positive economic performance is observed, stemming primarily from intensification of cattle production and additional energy crop production. Despite increasing irrigation efficiency in more intensive production systems, the water demand for perennial crops and cattle production over the dry season increases significantly, thus sustainable management practices that target efficient water use are needed. Agricultural productivity improvements, particularly for cattle production, are crucial for reducing the pressure on natural areas from increasing demand for both food products and bioenergy. This implies targeted investments in the agricultural sector and integrated planning of land use. Our results showed that production intensification in the Orinoquia region is a mechanism that could reduce the pressure on natural land and its associated environmental and economic impacts.

Runoff responses to human activities and climate change in an arid watershed of central Iran

ABSTRACT In this study, contributions of climate change and human activity to streamflow changes were estimated to enable decision makers to develop adaptation strategies for management of regional water resources. Flow trends and climate variables were analysed with the Mann-Kendall method. The year 1986 was selected to perform the Pettitt test to identify the change point of the runoff time series. Then, three methods were used for impact differentiation: climatic elasticity, least-squares support-vector machine (LS-SVM), and the soil and water assessment tool (SWAT). The results showed that climate change (38–67%) and human activities (33–62%) influence runoff reduction. Thus three management scenarios are introduced to reduce the effects of climate change and human activity: (1) adjusting wheat and barley cultivation levels; (2) maintaining wheat and barley cultivation levels and replacing other crops with potatoes; (3) increasing irrigation efficiency. All scenarios showed an increase in runoff, but the first scenario had the most impact.

Irrigation efficiency and renewable energy powered desalination as key components of Pakistan's water management strategy

Pakistan is reported to be one of the top ten, most water stressed, countries in the world. In this research, the potential to use renewable energy-based seawater desalination and improved irrigation systems to overcome the water stress in Pakistan is evaluated. It was observed that increasing the country's overall irrigation efficiency to 90% by 2050, results in a 54% and 80% reduction in total water and desalination demand, respective to a business as usual scenario. In a moderate scenario, where the maximum increase in irrigation efficiency is 1% per year, the 2050 total water and desalination demand are reduced by 21% and 40% respectively. The projected desalination demand growth, across the three scenarios, can be powered solely by renewables by 2050, at an average cost of water production of 0.6 €/m3. This includes the cost of water transportation in Pakistan and is reported to be an attractive water cost for farmers. Solar photovoltaics and battery storage drive the low cost electricity generation production in Pakistan. Thus, the results show how Pakistan can use improved irrigation efficiency systems and the low cost renewable electricity to achieve water security for the country.

Model of evapotranspirative subsurface irrigation tested with water lettuce

Providing irrigation for plants that is appropriate with the amount of the crop evapotranspiration or loss of water by plants is crucial to increase water productivity. One of the ways to increase irrigation efficiency is to apply a smart irrigation system. Intelligent automatic irrigation systems can be costly because they use a variety of microcontroller instruments. In this study, the irrigation model design utilizes automatic irrigation technology based on the evapotranspiration principle that can reduce the high cost. The objective of this study was to develop the evapotranspirative subsurface irrigation tested with water lettuce and test the performance of the model in terms of physical and economical water productivity. The evapotranspirative subsurface irrigation system used an inverted cone-shaped pots with an upper diameter of 40 cm. The pots consist of 1 pot as a supply of irrigation water, and 13 pots as planting pots. The pots are connected by a ½ in diameter pipe so that the water level at the pots is at the same level. The model yielded good results. The physical water productivity was 12.32 g liter−1 and economical water productivity of IDR 9.2/kg can save IDR 22.7/kg on irrigation water costs in crop production.

A hybrid approach associating flow network modeling with AHP-Entropy for simulating and ranking water-demand management alternatives

In view of the water crises historically experienced by Brazil’s semi-arid region, it is necessary to search for methodological tools that allow us to propose efficient alternatives for managing water demand. In this regard, the present study developed and applied a hybrid approach of flow network modeling and the Analytic Hierarchy Process (AHP) combined with Shannon’s entropy for simulating and prioritizing water demand management alternatives in the Epitácio Pessoa Reservoir in the Brazilian semiarid region. The approach initially performed simulations of the hydro system flow network to explore rational alternatives that evaluated the following criteria: meet the demands of human supply, meet the demands for irrigation, maintain the reservoir above the target volume, and reduce consumption. Subsequently, Shannon's entropy was used to assess the importance of the criteria and the multicriteria analysis of ranking of alternatives was built. Finally, a sensitivity analysis of the model was performed regarding the dependence on respective weights of the criteria. The results made enabled evaluation of the hydro system’s water security, highlighting insufficient supply by the single measure of water management transposition of the São Francisco River, and based on the hierarchy of alternatives, suggesting actions to improve the sustainability of water use, such as reuse of water, reduction of losses in supply systems and increasing irrigation efficiency. The proposed hybrid approach permitted the synthesis of the simulation’s results, which may simplify and support the decision-making process in water-demand management.

The Role of Farmer Personal Characteristics in the Adoption of Localized Irrigation Technology (LIT)

In Morocco, one of the most important and effective ways to combat the water crisis is to increase irrigation efficiency through the use of water-efficient irrigation technologies. Among the existing irrigation technologies, LIT has the highest efficiency rate (up to 90-95% irrigation efficiency). However, the adoption of this technology is low and continues at a slow pace. The main objective of this study is to identify and understand the role of individual variables in the adoption of localized irrigation technology (LIT) by farmers in the Draa-Tafilalt region. The results of the analysis of data collected by questionnaire from 400 farmers in the Draa-Tafilalt region showed that the variables Self-Efficacy, Attitude and Education Level had a positive and significant effect on the probability of LIT adoption at the 1% significance level. On the other hand, the variables Age and Experience had a negative and significant effect on the probability of adopting LIT at the 1% significance level. While the effect of the personal innovation variable on LIT adoption in the Draa-Tafilalt region was non-significant. The results of this work are of obvious practical and operational significance, as they provide information on the individual factors that condition the successful adoption of LIT by farmers. The results obtained can serve as a guide for action that leads to practical responses to the problems of irrigation water management and valuation in the study area. Our results are therefore beneficial not only to equipment suppliers and consultants but also to public officials responsible for supporting the integration of innovations in agriculture.

Combining Remote Sensing and Crop Models to Assess the Sustainability of Stakeholder‐Driven Groundwater Management in the US High Plains Aquifer

AbstractNonrenewable groundwater contributes ∼20% of global irrigation water. As a result, key agricultural regions around the world are on unsustainable trajectories due to aquifer depletion, threatening food production and local economies. With increasing resource scarcity in the central High Plains Aquifer in the United States, an innovative stakeholder‐driven groundwater management framework emerged in Kansas referred to as the Local Enhanced Management Area (LEMA) program. This framework enables groups of irrigators to join together to implement measures to conserve groundwater. Here, we assessed the efficacy of the first LEMA to move the region toward sustainability with a process‐based crop model driven by well records and satellite‐derived annual land use. We found increased irrigation efficiency under the LEMA program reduced groundwater extraction by 25% (40 million m3). However, only 22% of pumping reductions benefitted the net water balance (9 million m3) due to decreased irrigation return flow resulting from increased irrigation efficiency. We then estimated economic impacts using simulated crop yields, commodity prices, and estimated energy saved from reduced groundwater pumping. Cost savings from reduced pumping were about 4.5 times greater than the income lost from minor yield penalties. This suggests that the program promotes both economic and water sustainability, but water targets may need to be more strict to stabilize groundwater levels. As aquifer depletion threatens crop production in many parts of the world, approaches that integrate dynamic process‐based models with in situ and satellite data can inform economically and hydrologically sustainable management strategies. Our work highlights the need to consider both economic factors and root zone processes when evaluating irrigation conservation programs.

Irrigation efficiency, drain outflow and yield responses to drain depth in the Nile delta clay soil, Egypt

The conventional sub-surface drainage (FD) in the Nile delta clay soil, northern Egypt, results in excessive drainage and low irrigation efficiency (IE). However, a shallower placement of drain might reduce drain outflow and increase IE. The ultimate objective of the present study was to determine the optimum drain depth that minimizes drain outflow and maximizes IE and irrigation water use efficiency (IWUE), while maintaining crop yield and soil salinity. Compared to FD at 120 cm below the soil surface (BSS), the effect of four controlled drain depths (CD) at 40, 60, 80 and 100 cm BSS on drain outflow, IE, salinity buildup, yield and IWUE were investigated for two seasons (2017–18 and 2018–19; wheat-sunflower cropping system). Measurements were conducted for sunflower (as a summer crop). Irrigation was applied based on the soil water content of FD-treatment, thus irrigation depth varied for each treatment. The results showed that decreasing drain depth significantly reduced drain outflow and water input, while IE, seed yield and IWUE were increased. The maximum seed yield and IWUE were obtained at the shallowest drains. Compared with FD at 120 cm, drain depth at 40 cm decreased drain outflow (by 77.20%) and water input (by 29.3%), while increased seed yield and IWUE by 27% and 86%, respectively. Based on water balance, water-uptake from shallow groundwater was maximum for CD-40 cm treatment (31.05% of water-uptake) and was significantly higher than the other treatments. However, by the end of the second season, treatment with drain depth at 40 cm BSS recorded the highest soil salinity (3.6 dS m−1) due to the upward capillary rise of shallow groundwater. Increased soil salinity had no effect on seed yield because it was below the salinity threshold of sunflower. In terms of IE and IWUE, decreasing drain depth to 40 cm BSS is recommended, but with potential salinity buildup. Therefore, drain at 60 cm BSS (had similar seed yield to drain at 40 cm BSS) might lead to significant water-saving (21.8%), while maintaining seed yield and soil quality. In conclusion, modifying the drainage system by reducing drain depth and considering crop water-uptake from shallow groundwater might contribute to water saving. After all, careful water and soil management (e.g., periodic leaching), and suitable cropping systems should be considered for salinity management when decreasing drain depth.