Irrigation Demand Research Articles

Design and optimization of stand-alone hybrid energy system for rural areas

The main aim of this work to design and select the optimal photovoltaic based energy system that can meet the rural area irrigation and domestic load demand. The selection of optimal energy system configuration is based on modeling, economic and reliability analysis. Soft optimization computing tool (MATLAB & HOMER Pro) and Markov reliability method are used to identify optimal energy system configuration. The results show that COE of PV/battery is ₹6.87, PV/diesel/battery is ₹14.29, PV/DG is ₹30.25, DG/battery is ₹34.71 and DG is ₹36.12. Energy capacity shortage is higher in PV/battery (8%) and approx. zero in PV/DG/battery system. Reduction of fuel cost from diesel only system to hybrid PV/DG/battery energy system is 42.46%. PV/DG/battery failure rate (0.01101), EENS (0.080) and LOLP (0.00000725) are minimum as compared to another configuration. The obtained results concludes that hybrid PV/DG/battery energy system is cost-effective, sustainable and reliable system for rural areas in India.

Net irrigation requirement under different climate scenarios using AquaCrop over Europe

Abstract. Global soil water availability is challenged by the effects of climate change and a growing population. On average, 70 % of freshwater extraction is attributed to agriculture, and the demand is increasing. In this study, the effects of climate change on the evolution of the irrigation water requirement to sustain current crop productivity are assessed by using the Food and Agriculture Organization (FAO) crop growth model AquaCrop version 6.1. The model is run at 0.5∘lat×0.5∘long resolution over the European mainland, assuming a general C3-type of crop, and forced by climate input data from the Inter-Sectoral Impact Model Intercomparison Project phase three (ISIMIP3). First, the AquaCrop surface soil moisture (SSM) forced with two types of ISIMIP3 historical meteorological datasets is evaluated with satellite-based SSM estimates in two ways. When driven by ISIMIP3a reanalysis meteorology, daily simulated SSM values have an unbiased root mean square difference of 0.08 and 0.06 m3 m−3, with SSM retrievals from the Soil Moisture Ocean Salinity (SMOS) and Soil Moisture Active Passive (SMAP) missions, respectively, for the years 2015–2016 (2016 is the end year of the reanalysis data). When forced with ISIMIP3b meteorology from five global climate models (GCMs) for the years 2015–2020, the historical simulated SSM climatology closely agrees with the satellite-based SSM climatologies. Second, the evaluated AquaCrop model is run to quantify the future irrigation requirement, for an ensemble of five GCMs and three different emission scenarios. The simulated net irrigation requirement (Inet) of the three summer months for a near and far future climate period (2031–2060 and 2071–2100) is compared to the baseline period of 1985–2014 to assess changes in the mean and interannual variability of the irrigation demand. Averaged over the continent and the model ensemble, the far future Inet is expected to increase by 22 mm per month (+30 %) under a high-emission scenario Shared Socioeconomic Pathway (SSP) 3–7.0. Central and southern Europe are the most impacted, with larger Inet increases. The interannual variability in Inet is likely to increase in northern and central Europe, whereas the variability is expected to decrease in southern regions. Under a high mitigation scenario (SSP1–2.6), the increase in Inet will stabilize at around 13 mm per month towards the end of the century, and interannual variability will still increase but to a smaller extent. The results emphasize a large uncertainty in the Inet projected by various GCMs.

Effect of Rainfall Regime on Rainwater Harvesting Tank Sizing for Greenhouse Irrigation Use

The use of rainwater harvesting tanks to supply human water needs is an old and sustainable practice. In the case of covering irrigation demand in greenhouse agriculture, the potential is huge. Still, the relative research worldwide is low, while it is nearly absent in Greece. In this study, the rainwater harvesting tank size for irrigation use of greenhouse tomato cultivation was investigated by applying a daily water balance model in three regions of Crete Island (Greece) with significant greenhouse areas. Daily rainfall data from three representative rainfall stations of the study areas characterized by different rainfall regime for a 12-year time series were used. Additionally, the daily irrigation water needs for a tomato crop during an 8-month cultivation period were used. The greenhouse roof was defined as catchment area of the rainwater harvesting system and greenhouse areas of 1000, 5000 and 10,000 m2 were studied. In all areas examined, a tank of 30–100 m3 per 1000 m2 of greenhouse area could reach approximately 80–90% reliability. Higher values of reliability (reaching 100%) could be achieved mainly with covered tanks. Tank size for 100% reliability in covered tanks, ranged from 200 m3 (per 1000 m2 of greenhouse area) in the study area with high mean annual rainfall depth (974.24 mm) and moderate mean longest dry period (87.67 days), to 276 m3 (per 1000 m2 of greenhouse area) in the study area with relatively low mean annual rainfall depth (524.12 mm) and high mean longest dry period (117.42 days). For uncovered tanks, a 100% reliability value could be reached only with a tank size of 520 m3 (per 1000 m2 of greenhouse area) in the study area with high mean annual rainfall depth and moderate mean longest dry period.

Optimal Implementation of Climate Change Adaptation Measures to Ensure Long-term Sustainability on Large Irrigation Systems

Observed and projected consequences of climate change on streamflow generated in the Pyrenees threatens the long-term sustainability of water resources systems downstream, especially those with high irrigation demands. To tackle this challenge, the participation of stakeholders in defining potential adaptation strategies is crucial to building awareness and capacity for the community, providing agreed solutions, and reducing conflict. However, there is also a need for a top-down approach to incorporate other, large-scale, or innovative adaptation strategies. This article describes a bottom-up-meets-top-down approach to estimate the optimal implementation intensity of adaptation strategies under different climate scenarios on a complex water resources system. Future streamflow projections were used in a water allocation model combined with a Markov Chain Monte Carlo sampling process to obtain optimal combinations of measures to meet different sustainability objectives. The methodology was applied to the Gállego-Cinca River system in NE Spain, which relies on water from the Pyrenees. A stakeholder workshop identified storage development and irrigation modernisation as the preferred adaptation options. However, the modelling results show that more storage in the basin, especially on-farm reservoirs, is not enough to maintain current sustainability levels. This will enable the adoption of demand management measures that optimise water use despite not being among stakeholder preferences.

Irrigation demand of economically significant crops in the Araras Norte and Baixo Acaraú districts, Ceará, Brazil

The aim of this study was to analyze the water demand in banana, papaya and coconut crops grown in the irrigation districts of Araras Norte and Baixo Acaraú, located in the State of Ceará. A historical meteorological series of the regions where the irrigation districts from this study are located was used. Precipitation, maximum and minimum temperatures, and relative humidity data were obtained from these historical series. From the acquired precipitation data, to analyze the frequency and intensity of dry and rainy years in the area, the Rainfall Anomaly Index was calculated. Based on the meteorological data from the historical series, the reference evapotranspiration by the Hargreaves-Samani method and the crop evapotranspiration were determined. The crop water requirement was obtained based on crop evapotranspiration and precipitation. In the plots, irrigation systems were evaluated and the application efficiency was determined in order to obtain the supplementary irrigation requirement. The irrigation depths used in the Araras Norte and Baixo Acaraú irrigation districts were underestimated, not meeting the supplementary irrigation requirement. For banana and papaya crops in the Araras Norte irrigation district, performing irrigation in the first semester and applying irrigation management throughout the year could correct the water deficit. For banana and coconut crops in the Baixo Acaraú irrigation district, it would be necessary to correct the irrigation depth in the second semester, through adequate irrigation management, because in the first semester precipitation would be sufficient to meet the crop water requirement.

Fabric Containers Increased Irrigation Demand but Decreased Leachate Loss of Nitrogen and Phosphorus Compared With Conventional Plastic Containers During Production of Dwarf Burford Holly

Fabric containers (FAB), due to their root-pruning properties, can be used as an alternative to conventional plastic containers (PLA) in container nurseries. Because sidewall evaporation in FAB has been shown to reduce container substrate temperatures, our objective was to determine if FAB would reduce the release rate of controlled-release fertilizer (CRF), resulting in less leachate loss of nitrogen (N) and phosphorus (P) and greater CRF longevity. Dwarf Burford holly were grown in 36-cm-diameter (18-L substrate) FAB or PLA in a bark-peat substrate with incorporated CRF. Spray stake irrigation was routinely adjusted to a target leaching fraction of 25%. Maximum daily substrate temperature, measured 3 cm from southwest-facing container wall, averaged 6 °C lower in FAB than in PLA. For two 31-week experiments where leachate was continuously collected and sampled weekly, FAB reduced leachate N loss by 30% and P loss by 47% despite requiring 66% more irrigation water and collecting 31% more leachate than with PLA. FAB reduced average N loss from 114 to 78 kg·ha−1 and average P loss from 16.0 to 8.6 kg·ha−1. FAB increased plant size by 8% and shoot dry weight by 12% for one experiment but had no effect in the other. We concluded that compared with PLA, the use of FAB can decrease leachate loss of N and P but require considerably more irrigation water to offset water loss via sidewall evaporation.

A Study on Precipitation Change and its Impact on Wheat Cultivation in Sulaimaniyah Region, Iraq

Using a production function method and district-level data from 1941 to 2020, this study examines the influence of climate change on wheat cropped area in Sulaimaniyah. The data for these time periods provide evidence of an increase in mean rainfall. Since the quantity of rain that fell on Sulaimaniyah during the 79-year research period is averaged out, it comes to 679 mm, which is a good rate for fulfilling agricultural irrigation demands in this location, especially when an essential crop like wheat requires about 450 mm for adequate output. Only nine years, out of the 79 years analyzed, had less than 450 mm of rain, while the rest had more than 450 mm. During the research period, variations in rainfall quantities had an impact on the farmed areas. Season 2019-2020 cultivated about 39250 hectares in Sulaimaniyah Region, with precipitation of 746 mm, while the season before that was one of the wettest, with 1317 mm rain. For the rainy years, which allow greater areas for cultivation, the visual distribution of cultivated areas across the study years reveals a semi-organized pattern. Seasons 2006-2007, 2007-2008 and 2008-2009 were three of the driest seasons, with agricultural areas reduced to bare minimums despite acceptable rainfall levels, although those years were not drought years, since a drought year is defined as a year with less than 300 mm of rain.

Assessment of Crop Water Demand and Irrigation Water Supply in a Run-off-the-river Based Canal System

Proper assessment of irrigation water need for a canal command is required for long term planning and management of water resources. The present study was carried out in the Phulnakhara distributary command of the Puri main canal system distributed in Cuttack and Khurda districts of Odisha. During Kharif season, the Phulnakhara distributary command receives more than the required amount of irrigation water. However, during Rabi season, the canal does not flow at its full supply level as a result of which the total irrigation demand of the canal command area is not met leading to lower cropping intensity and poor crop productivity. The year-wise highest irrigation water demand in Kharif season was found to be 48646195 m3 during 2015-16 and the lowest was 22291100 m3 in 2017-18. Whereas the highest Kharif irrigation supply at the head regulator was 43402176 m3 during 2015-16 and the lowest was 29831328 m3 during 2013-14. The highest Rabi irrigation water demand was found to be 21700766 m3 during 2008-09 and the lowest was 9570257 m3 in 2017-18. Whereas the highest Rabi irrigation supply at head regulator was 26379648 m3 during 2008-09 and the lowest was 615168 m3 during 2009-10. As evident, there is a mismatch between the supply and demand in both the seasons and it is more prominent in the Rabi season. In order to bridge this gap, conjunctive use of canal water with groundwater is found to be a promising solution.

County-Level Irrigation Water Demand Estimation Using Machine Learning: Case Study of California

Irrigated agriculture is the largest consumer of freshwater globally. Despite the clarity of influential factors and deriving forces, estimation of the volumetric irrigation demand using biophysical models is prohibitively difficult. Data-driven models have proven their ability to predict geophysical and hydrological phenomena with only a handful of influential input variables; however, the lack of reliable input data in most agricultural regions of the world hinders the effectiveness of these approaches. Attempting to estimate the irrigation water demand, we first analyze the correlation of potential influencing variables with irrigation water. We develop machine learning models to predict California’s annual, county-level irrigation water demand based on the statistical analysis findings over an 18-year time span. Input variables are different combinations of deriving meteorological forces, geographical characteristics, cropped area, and crop category. After testing various regression machine learning approaches, the result shows that Gaussian process regression produces the best results. Our findings suggest that irrigated cropped area, air temperature, and vapor pressure deficit are the most significant variables in predicting irrigation water demand. This research also shows that Gaussian process regression can predict irrigation water demand with high accuracy (R2 higher than 0.97 and RMSE as low as 0.06 km3) with different input variable combinations. An accurate estimation of irrigation water use of various crop categories and areas can assist decision-making processes and improve water management strategies. The proposed model can help water policy makers evaluate climatological and agricultural scenarios and hence be used as a decision support tool for agricultural water management at a regional scale.

Quantifying the potential impacts of climate change on irrigation demand, crop yields, and green water scarcity in the New Jersey Coastal Plain

Climate change has significant implications for irrigated agriculture and global food security. Understanding how altered precipitation patterns and magnitudes, coupled with rising growing season temperatures, affect irrigation demand and crop production is a prerequisite for formulating effective water resources management strategies. This study evaluated the effects of near-term climate change (centered on 2035) on irrigation demand, green water scarcity, and row crop yields in a major agricultural watershed in southern New Jersey, USA. Downscaled precipitation and temperature from six General Circulation Models (GCMs) for two representative concentration pathways (RCP-4.5 and 8.5) from the Coupled Model Intercomparison Project Phase 5 (CMIP5) were used to drive the Soil and Water Assessment Tool hydrological model.Temperature and precipitation increases resulted in greater surface runoff, lateral flow, groundwater recharge, and total streamflow. Seasonal ET for corn is projected to alter between −3.0 % to 0.5 %, with irrigation demand between −17 % to −1 %, and yield ranges between −4 % to +9 % depending on the GCMs in the RCP-4.5 scenario, with similar patterns projected by RCP-8.5 scenario. For soybean, the simulation also indicates a declining trend of ET and irrigation demand while increasing yield. Increasing yield for both crops is attributed to changes in agronomic management practices combined with genetically improved cultivars and higher soil fertility due to CO2 fertilization. Green water scarcity analysis under future climate change for corn and soybean display a decreased soil moisture stress due to increased water use efficiency resulting from reduced stomatal conductance under elevated CO2 concentration.

The Role of Groundwater Withdrawals on River Regulation: Example From the Columbia River Basin

AbstractThe Columbia River Basin (CRB) is heavily regulated by more than 250 dams on its river system while depending significantly on groundwater withdrawals in certain sub‐basins. Neglecting groundwater withdrawals in hydrologic models of the basin could result in inaccurate predictions of its water budget and thus mislead water management decisions in the basin. This study aims to understand the impacts of groundwater pumping on the spatiotemporal patterns of modeling regulated streamflow in the CRB using a modified version of the Variable Infiltration Capacity (VIC) model integrated with a water management component that accounts for groundwater withdrawals, irrigation demands, and reservoir operation (VIC‐GIRR). The VIC‐GIRR simulations showed that considering additional groundwater withdrawals would alleviate the stress of irrigation water deficit in the Snake River Basin with an average reduction of 10 km3/year. Such a reduction in water deficit resulted in slight streamflow increase over the CRB with maximum increase up to 40% during dry period in certain locations. We also note that the implementation of groundwater withdrawal does not, however, improve the overall model performance in long‐term averaged streamflow and storage predictions. Our results highlight the efforts needed to examine additional important processes in representing the interactions between water withdrawals and reservoir operations. Such efforts will aid in better simulation of multi‐reservoir system and improve effectiveness for agricultural productivity, power generation, flood control, and navigation purposes.

Increased profitability and energy savings potential with the use of precision irrigation

Energy is currently one of the main production costs in irrigated agriculture and its cost must always be considered in irrigation projects. In regions such as the Brazilian Cerrado, where there is a continuous growth of irrigated agriculture, it is important to evaluate technologies that can increase the efficiency and viability of irrigation. Precision irrigation has great potential to increase the economic return on rural properties with a reduction in electricity consumption. The present work aimed to evaluate the increased profitability and energy savings potential of the soybean crop using precision irrigation with a center pivot. To evaluate the potential benefits of precision irrigation (PI), irrigation demand was simulated through modeling. The irrigation computer model was developed in Python language. The study was carried out in the area of two center pivots with soils with different hydro-physical characteristics. Soil available water capacity (AWC) was calculated based on field capacity, permanent wilting point and bulk density data. The irrigation management under homogeneous soil conditions was carried out considering the lowest, the average, and the highest AWC value. The management under variable conditions was carried out individually for each pixel, considering the real AWC value of the pixel. Also, four sowing dates of the soybean crop were considered in a rainy year and a dry year. The results indicated an average energy savings potential (ESP) of 5.0% in the rainy year and 4.5% in the dry year. The average potential for increasing profitability (IPP) was 20.4% in the rainy year and 12.5% in the dry year. The use of PI can reach ESPs of up to 25.3% and IPPs of up to 106.2%. The benefits documented here are an important step towards the development of precision irrigation as an efficient irrigation management strategy.

Banana growing and its climate suitability in the municipality of Recife-Pe, Brazil

The banana tree is a plant characteristic of the tropical region, demanding in temperatures and rainfall with good regional distribution, due to its low cost and high nutritional value, it is an integral part of the diet of populations. The objective is to analyze the climatic oscillations, from the calculation of the water balance and its climatic classification, according to the methods of Thorn Thwaite and Köppen, for the city of Recife, verifying the occurrence of the aptitude of the banana cultivar. The average rainfall and temperature data were acquired from the National Institute of Meteorology, for the period between 1962 and 2016. Banana plantations are moderate because they have a water deficit of 287.4 mm. The evaporative power registered in the municipal area is high, but the demand for irrigation complements the scarcity of water to cultivate it. The local altitude is in the range of planting of the cultivar as well as the variability of the relative humidity of the air. Wind is one of the limiting factors for commercial exploitation of banana cultivation, if the cultivars are tall and planted in sandy soils.

Historical climate change impacts on the water balance and storage capacity of agricultural reservoirs in small ungauged watersheds

Study regionAgricultural reservoirs are the principal source of irrigation supplies for sustaining rice production and play a critical role in the water resource management of South Korea. Study focusWe comprehensively evaluated the performance of 400 major agricultural reservoirs, spread throughout the country, as a function of climate change during 1973–2017 considering the constituents of reservoir water balance, such as watershed runoff, irrigation water demand, and evaporation loss. New hydrological insightsBased on the trend analysis during the 45-year study period, the reservoir inflows remained higher than the irrigation water demands because of the gradually increasing annual rainfall. Most reservoirs had enough storage capacities; their resilience gradually declined particularly during the last 15 years. The northern and northeastern region reservoirs had acceptable resilience whereas the reservoirs in the western and southwestern inland and coastal regions showed insufficient resilience. Reservoirs received sufficient inflows but the residence time of the excess inflow has to be increased to suffice the peak irrigation demands in the coming cropping season. Study outcomes could help prioritize the reservoirs requiring immediate rehabilitation located in the central and southwest regions with high failure risks. Results suggested that a reservoir with a watershed-irrigated area ratio > 5 would have a better chance of coping with future climate change threats.

Participatory design of robust and sustainable development pathways in the Omo-Turkana river basin

Study regionOmo-Turkana Basin, trans-boundary basin between Ethiopia and Kenya (North eastern Africa). Study focusSignificant investments in large dams have been mobilized in the Omo-Turkana basin to expand hydropower and support extensive irrigation projects. Assessing the impacts of these infrastructures, particularly on local stakeholders, constitutes a crucial foundation for socially inclusive as well as environmentally and economically sustainable development. This study showcases the potential of a participatory decision-analytic framework in investigating the impacts of alternative development pathways on competing stakeholders’ interests in the Omo-Turkana basin to support strategic planning under both current and projected hydroclimatic and socio-economic conditions. The optimal operation of the planned system expansion, including the current and future dam cascade and the irrigation projects, is investigated to provide insights into multisectoral trade-offs. Five main sectors with competing interests are considered: hydropower production, environmental protection, indigenous recession agriculture, fish yield in Lake Turkana, and large-scale commercial irrigated agriculture. New hydrological insights for the regionResults show that the planned infrastructure can negatively impact local stakeholders, particularly in terms of fish yields in Lake Turkana. Still, a potential exists for negotiating operational compromises that are both efficient and socially inclusive. Moreover, even though the performance of the planned infrastructure is expected to decline in the future under changing climate and irrigation demands, this can be mitigated by timely implementing robust solutions triggered by the alterations of streamflows in the northern part of the basin.

Impact of drought and salinity on olive potential yield, oil and fruit qualities (cv. Chemlali) in an arid climate

The increase water demand for irrigation is leading to the use of low-quality water resources. The combined impact of drought and salinity on olive production sustainability, yield quality, growth, soil salinity and soil water conditions in arid areas has been little investigated. This study’s purpose was conducted to investigate the effects of the monitoring of saline water irrigation on soil properties and olive trees (cv. Chemlali) grown in an arid region of Tunisia (Sfax), on the potential yield, growth and quality of the resultant virgin olive oil in comparison to Rain-fed conditions. It is also intended to compare olive productive performance during a severe drought with, and without, irrigation and to assess recovering capacities after long driest period. Three irrigation levels were considered: (i) Full irrigation (100%ETc) with saline water 7.5 dS m-1 (FI); (ii) Full irrigation with same amount of water than the FI applied with tap water 2.46 dS m-1 (TW); and (iii) Rain-fed conditions (Dry). The results have showed that irrigation with saline water maintained the soils permeability, induced the distribution of salts outside the root zone. Additionally, it has maintained an adequate hydration of the rhizosphere through continuous and efficient leaching of salts to deep horizons. After drought period, the increase of the yield of rain-fed trees indicated 50% of recovery as compared to saline water. Irrigation with saline water reduced this gap due to drought impact. But it was 50% under that tap water; while reduction was 15% as a reduction capacity of potential yield. Hence, drought and salt stress alter the olive tree capacity and potential yield in an irreversible way if their severity is very intense. As salinity increased, there was a desirable sink in measured total phenols and flavonoids levels and a rise of oleic and linoleic acids as compared to rainfed conditions. For the triglycerides composition, triolein (OOO) was present in very large quantity in three oils, with a high content for FI (23.94%). Saline water treatment did not affect free acidity, peroxide value, K232, K270, chlorophyll, carotenoids, in contrast to Rain-fed treatment which was decreased. Olive trees permanently lost less than half of their potential yield during drought without irrigation. Irrigation with saline water seems to ensure sustainable monitoring olive yield and oil quality.

Changing occurrence of crop water surplus or deficit and the impact of irrigation: An analysis highlighting consequences for rice production in Bangladesh

Disentangling the impacts of water deficit and lack of irrigation infrastructure on critical food supplies such as rice in countries like Bangladesh remains a challenge. In this paper, we explore this challenge using North Bengal as a case study site over 1979–2018. We characterise crop water surplus/deficit with meteorological and soil moisture data and analyse the coherence of these timeseries with rice production in the study region. We then examine the trends, periodicities and degree of coherence between crop water surplus/deficit, irrigation, and rice production. Our results indicate an almost constant water deficit during winter and maximum water deficits in the pre-monsoon and post-monsoon periods. Critically, crop water surplus shows a significantly decreasing trend since 1979 during the monsoon period. We find that the correlation between crop water surplus/deficit, while strongly correlated with meteorological drought, weakens over time. This is suggestive of the important role that irrigation development has played over this period. Although the severity and frequency of water deficits have increased during the study period, possibly as a result of climate change or variability, rice production has decoupled from this trend and is instead positively correlated with irrigation. Despite this encouraging finding, it is unknown if technological progress will continue and whether there will be sufficient extractable groundwater and surface water to meet increasing irrigation demand in the future. Our finding of a long-term increase in water deficit underscores the likely future challenges in these critical rice growing regions for the people of Bangladesh, should this trend continue. The future sufficient rice production in the region will likely rely on the availability of reliable and affordable fuel or electric power to operate irrigation systems and a proactive and vigilant approach to agricultural water security in a variable and changing climate.

The need for agricultural productive uses in the national electrification plan of sub-Saharan African countries—a call to action for Ethiopia

Abstract Access to electricity is a crucial aspect of sub-Saharan Africa’s path towards development. In light of the potential for electricity access to improve quality of life, the United Nations aims to achieve universal access to ‘clean, reliable, affordable and modern’ electricity as Goal 7 of its Sustainable Development Goals (SDG 7). As such, governments of sub-Saharan African (SSA) countries, such as Ethiopia, have developed national electrification plans to outline their pathway to universal access to electricity. In this paper, we identify why it is essential for the national electrification plans of SSA countries to prioritize electricity access for productive uses in its agricultural sector, using Ethiopia as a case study. Reviewing existing literature and using the authors’ research, we point out that there is 3.04 terawatt-hours of latent demand for small-scale pressurized cereal-crop irrigation alone in Ethiopia. Supplying this electricity demand for small-scale irrigation could lead to a reduction in the levelized cost of electricity of up to 95%. We conclude our paper by recommending the creation of a cross-sector national productive use commission that would be tasked with collecting and sharing relevant data from each sector and collaboratively creating a national productive use program that would ensure that Ethiopia reaps the full benefits and potential for wealth creation from access to electricity.

Managing environmental impacts of water and energy use by a multipurpose cropping pattern optimization

Abstract The present study proposes a multipurpose cropping pattern optimization to minimize the environmental impacts of water and energy use on agriculture through the income–energy–river ecosystem nexus approach in different hydrological conditions. The following three main purposes are considered in the optimization model: (1) mitigating greenhouse gas emissions due to farming by considering minimization of agricultural energy consumption; (2) mitigating environmental impacts on the river ecosystem by considering it as the main source for supplying irrigation demand in the case study and (3) maximizing farmers’ income. Field studies are carried out in the case study for recording energy inputs to assess average energy use, irrigation demand, production yield and other required parameters for the selected crops. The fuzzy physical habitat simulation is utilized to develop an environmental impact function in the river ecosystem. Based on the results of the case study, the optimization model is able to balance energy use, impacts on the river ecosystem and farmers’ income. However, its performance is not best in terms of all the defined purposes. The results indicate that more than 50% of the initial income is provided, while energy use is mitigated by more than 70% on average. Furthermore, the river ecosystem is protected properly.

Modified Hydrological Regime on Irrigation and Water Supply in Lake Areas: A Case Study of the Yangtze River–Dongting Lake

Lake systems are of fundamental significance for the ecological environment and social development. Driven by climatic changes and human activities, the hydrological situation of rivers and lakes has been altered considerably, and it has directly affected the reliability of irrigation and water supply in lake areas. In the case of the Yangtze River–Dongting Lake area, the quasi-equilibrium of their hydrological states and water balance have been affected by the operation of the Three Gorges Project that has led to irrigation and water supply problems across the lake area. Ever since, the available water supply in the Dongting Lake area has decreased by 31.5% and 47.7% during the months of September and October, and the overall water level in the lake area has dropped by 0.8–2.0 m. The proportion of domestic and agricultural irrigation water demands to available water supply in the Dongting Lake area is very small, and the decline of water level is the main reason for the lack of water supply in Dongting Lake area, Although the total amount of water in the lake area is still above the water supply threshold, an obvious decreasing trend has been observed in the fulfillment of the demand for both irrigation and water supply in urban and rural regions. Additionally, the fulfillment of secured water supply and irrigation requirements has respectively dropped from 95% to 78% before the operation of the Three Gorges Project to 82% and 46% after it. Meanwhile, the total water shortage increased from 57.683 to 143.607 million cubic meters. By advancing or postponing impoundment schedules, the impact of the Three Gorges Reservoir on irrigation and water supply in the lake area during September and October can be alleviated, and the water supply capacity can be respectively increased by approximately 1.3% and 1.4%. The highlights of this study include the quantification of the impacts of the operation of large-scale water conservancy projects at the level at which the requirements on irrigation and water supply in the lake area are satisfied, and the prediction of the trends for future evolvement. In addition, corresponding strategies that provide a technical reference for the comprehensive regulation and control over water resources and the security of water supply in the river basin are discussed.