Irrigation Schemes Research Articles

Transforming Arid and Semi-Arid Areas to be Food Secure: The Role of Small-Scale Irrigation Projects

The primary aim of this research was to evaluate the contribution of irrigation-based initiatives towards ensuring food security. The specific objectives encompassed assessing the role of labor within small-holder irrigation projects in bolstering food security, analyzing the impact of external donor assistance on food security outcomes within these projects, and appraising the extent of governmental backing for small-holder irrigation endeavors in the pursuit of food security goals. Employing a descriptive survey methodology, the study was conducted within various small-holder irrigation projects. The research population consisted of 1303 members affiliated with the irrigation schemes, alongside 12 agricultural officers. Utilizing a simple random sampling technique, two agricultural extension officers were selected from the irrigation schemes, while a stratified sampling approach identified 66 irrigation scheme members for participation in the study. Data collection primarily relied on the administration of questionnaires. Findings revealed that the majority of farmers predominantly relied on their labor or that of family members, with minimal utilization of hired labor observed in small-scale irrigation ventures. Consequently, labor scarcity emerged as a notable challenge within these projects. Furthermore, the study highlighted that a significant proportion of small-holder irrigation initiatives benefited from external donor support. To address labor shortages, the research suggested incentivizing specialized labor while recommending collaborative efforts among farmers to engage specialists in crop management, thereby enhancing crop productivity within the schemes.

Design and Retrofitting of Irrigation Pumping System for the Middle Ogun Irrigation Project Using Hydrokinetic Technology

High cost of irrigation pumping by use of fossil fuel has negatively impacted irrigation efficiency on the Middle Ogun Irrigation scheme. Efficient irrigation pumping would improve agricultural productivity and food production on the irrigation scheme.  Many attempts have been made by stakeholders to seek alternative energy sources for powering irrigation pumping. This study aimed at the design and retrofitting of the irrigation water pumping system on the Middle Ogun Irrigation scheme using hydrokinetic technology. Hydrological modelling of the catchment was carried out using MapWindow Soil and Water Assessment Tool to determine the annual gross and recoverable hydrokinetic potential of the water resource from the river. A Savonius hydrokinetic turbine system was developed and tested on the river.  The mean voltage output at selected streamflow depths were determined to derive a power curve. Results showed that retrofitting the irrigation pumping system with an array of twenty units (20) of selected submersible irrigation pumps powered by twenty-two (22) units of an array of Savonius hydrokinetic turbines would satisfactorily deliver irrigation water into night storage and irrigate the pilot field of 100 ha of farmland on plot 2 and 5 on the scheme.

Study on irrigation scheme and nitrogen application to sunflower (Helianthus annuus L.) in saline farmland in the arid/semi-arid region of Hetao Irrigation District

Study on irrigation scheme and nitrogen application to sunflower (Helianthus annuus L.) in saline farmland in the arid/semi-arid region of Hetao Irrigation District

Effect of Bioactive Compound (Poultry Manure) on the Yield and Capsaicinoid Content of Sweet Pepper (Capsicum annuum L.) Cultivars

To assess the impact of poultry manure fertilization on the yield and capsaicinoid content of sweet pepper cultivars, field experiments were carried out during the 2018 rainy seasons at two locations within the Sudan savanna agro-ecological region: the Teaching and Research Farm Bayero University Kano (l1o 58 N, 8o 25 E, and altitude 458 m) and Kadawa Irrigation Scheme Bunkure (l1o 42 N, 8o 33 E, and altitude 476 m). The experiment was a 4 x 3 factorial laid out in a randomized complete block design with four replicates comprising four levels of poultry manure (PM) (0, 1.0, 2.0, and 3.0 tha-1) and three cultivars of sweet pepper (Tattasai Dan Damasak, Yolo wonder and Nsukka yellow). The result reveals that the growth, yield and capcisinoid content of sweet pepper cultivars were greatly influenced by the application of PM. The application of 3.0 tha-1 of PM significantly gave taller plants, more branches, larger leaves, and a higher number of fruits. Similarly, the Dan Damasak cultivar significantly produced higher growth characters above, except for the number of fruits plant-1. The Dan Damasak and Yolo wonder cultivars at BUK and Yolo wonder at BKR significantly gave a higher number of fruit plants. Fresh fruit yield, total fruit yield, and capsaicinoid content were significantly higher with 3.0 tha-1 of PM at both locations. The Dan Damasak cultivar resulted in higher yield related characters at both locations. The capsaicinoid content was, however, significantly higher with Nsukka yellow (17.43 and 18.83 mg kg-1) at BUK and BKR locations, respectively. Thus, the application of 3.0 tha-1 PM combined with the Dan Damasak cultivar for improved growth and yield, while the Nsukka Yellow cultivar and the application of 3.0 tha-1 PM for higher capsaicinoid could be suggested to the farmers in the study area to improve the productivity of the crop.

Performance evaluation of the Bilate and Furfuro irrigation schemes in Silti Zone, southern Ethiopia

Many irrigation schemes are performing poorly for a number of reasons, and this should be improved to increase the efficiency and productivity of the schemes. This study attempted to determine the performance of the Bilate and Furfuro irrigation schemes in Silti Zone, southern Ethiopia. For field data measurements, three farmers’ fields were selected at the head, middle, and tail end of each scheme. Average conveyance efficiencies were 53% and 56.1%, average field application efficiencies were 55.9% and 58.0%, average water storage efficiencies were 53% and 46.5%, irrigation uniformity was 91.03% and 92.9%, and overall irrigation efficiency was 28% and 32% for Bilate and Furfuro schemes respectively. This implied that the two schemes were performing inefficiently and inadequately, but water was distributed uniformly. The reason might be most canal sections had unreasonable losses of water in two schemes. Additionally, relative water supply was 0.68 and 0.79, relative irrigation supply was 0.61 and 0.77, output per unit irrigated area was 4140.4 and 1781.5 ($/ha), output per unit command area was 4510.3 and 1968.5 ($/ha), output per unit irrigation supply was 0.94 and 0.28 ($/m3), output per unit water consumed was 0.99 and 0.39 ($/m3), sustainability of irrigation area was 1.05 and 1.02, and irritation ratio was 1.11 and 1.09 for Bilate and Furfuro schemes respectively. This revealed that the applied water was not satisfied the crop water demand, but their irrigated lands were expanded for two irrigation schemes. Furfuro scheme was better than Bilate in terms of relative water supply and relative irrigation supply, but their results obtained were below acceptable values. However, Bilate scheme had significantly better land and water productivity than Furfuro scheme. This may be use high value crops, better agricultural inputs, and removal of grass cover and sedimentation from canal systems. Hence, Bilate irrigation scheme was better performing than Furfuro scheme. Therefore, adopt the best practices learned from Bilate irrigation scheme for the Furfuro scheme.

Empowerment of farmers through participatory irrigation management in Bihar, India

AbstractPoorly performing irrigation schemes in India require technical, managerial and institutional support on an urgent basis. In recent years, participatory irrigation management (PIM) has gained momentum as a strategy to improve the performance of irrigation systems, increase water use efficiency and promote equitable water distribution. This approach involves the active involvement of farmers and other stakeholders in the planning, implementation and management of irrigation systems. The state of Bihar has primarily an agrarian economy and irrigation is essential for agricultural production. However, Bihar's irrigation potential is being underutilized due to improper management of irrigation systems. In Bihar, the experiment of PIM in the Paliganj distributary of the Sone irrigation scheme was attempted as a local initiative by WALMI Patna, which was funded by USAID, and, thus, the need for an overall state policy and strategic plan was realized. Therefore, PIM has been implemented through the formation of water users' associations (WUAs) and farmers’ organizations (FOs) at different levels under the Bihar Irrigation Act of 1997, and Bihar Irrigation, Flood Management and Drainage Rules, 2003. The Bihar model of PIM is based on the macro‐to‐micro approach because of its geographical conditions and the size of the schemes in the state. This paper examines the implementation of PIM in Bihar and its impacts on farmers.

Are rice systems sustainable in Sri Lanka? - A case of Deduru Oya reservoir irrigation scheme

Sustainable rice systems play a crucial role in achieving sustainable development goals, particularly in countries like Sri Lanka that heavily rely on paddy production. The study aims to examine the economic, social, and environmental sustainability gaps of a rice production system at various spatial scales using the Sustainable Rice Platform (SRP) framework v2.1 and identify interventions that can address these gaps. Data for the study was collected through a structured questionnaire, which incorporated the 12 performance indicators of the SRP framework, including profitability, labor productivity, grain yield, water productivity, nutrient use efficiency, biodiversity, greenhouse gas emission, food safety, health and safety, child labor and youth engagement, and women empowerment. The survey was conducted over two consecutive cropping seasons, in 2019 dry and 2019/2020 wet seasons, in selected paddy fields representing three topo-sequences within the Deduru Oya irrigation project in Sri Lanka. The study's findings revealed that the rice systems' profitability ranges from 475 ± 45 to 642 ± 59 USD/ha across seasons and topo-sequences, and a yield gap of approximately 33% was observed. Substantial exploitable gaps were observed in labor productivity (67%–77%) and water productivity (58%–68%). Additionally, there was significant variability in nutrient use efficiency and greenhouse gas emissions due to variations in water management practices. The social sustainability of rice systems has received lower scores, particularly for health safety and women empowerment. The study attributed most of the economic and environmental sustainability gaps in the agricultural practices of cultivators, while various socio-political and cultural factors influenced the social sustainability gaps. This study offers valuable insights to policymakers and practitioners in countries with extensive rice systems, aiding their efforts toward achieving sustainable development goals.

Climatic impacts induced by winter wheat irrigation over North China simulated by the nonhydrostatic RegCM4.7

Quantification of the impact of winter wheat irrigation on the climate and the occurrence of extreme climatic events over North China is crucial for regional adaptation planning. Previous related studies mainly focused on the impact on surface processes; however, few focused on the effects of extreme events using high-resolution nonhydrostatic regional climate models. Here, the 9-km-resolution nonhydrostatic RegCM4.7 was coupled with a crop irrigation scheme and an updated winter wheat irrigation dataset to better simulate irrigation effects. Two experiments were conducted with and without winter wheat irrigation to isolate the effects of irrigation. Results showed that irrigation simulation reduces the model biases in temperature, precipitation, latent heat flux, soil moisture, sensitive heat flux, and top-layer soil moisture. Moreover, it also reduces the bias and increases the correlation with observations obtained in irrigated areas, especially in summer, indicating better representation of irrigation schemes. Winter wheat irrigation tends to cause substantial cooling of the local surface maximum, minimum, and mean air temperatures (by −0.79, −0.34, and −1.68 °C, respectively) over irrigated areas of North China, with the largest changes observed in relation to maximum temperature. Additionally, precipitation is found to increase during spring and summer, which is strongly related to water vapor transport in the lower levels of the atmosphere. Further analyses indicated that the number of annual mean hot days decrease (−13.9 d), whereas the number of both comfort days (+10.2 d) and rainy days (days with total precipitation greater than 1 mm: +6.6 d) increase over irrigated areas, demonstrating beneficial feedback to human perception and agriculture. Fortunately, although the heat wave risk increases (number of annual mean heat wave days: +5.8 d), the impact is limited to small areas within irrigated region. Additionally, no notable change was found in terms of heavy rainfall events and precipitation intensity, which might be an undereastimation caused by the less water use in model simulation. Although winter wheat irrigation does not have notable impact on the climate of the surrounding region, it is an important factor for the local-scale climate.

Integrated assessment of irrigation and agriculture management challenges in Nepal: An interdisciplinary perspective

Agriculture plays a critical role in ensuring food and nutrition security, livelihood, and rural employment in Nepal. Despite substantial investments and institutional reforms, irrigation projects have faced consistently low performance. While existing studies have shed light on technical aspects of irrigation performance, they often focus on specific themes rather than holistic evaluations of sustainability. This research systematically assesses barriers and challenges to effective irrigation water management in Nepal by assessing and ranking the challenges faced by three irrigation systems located in western Nepal: Mahakali, Rani Jamara Kulariya, and Babai. To investigate these challenges, we collected data from 449 households, which provided insights into 33 indicators representing key barriers to effective irrigation and agricultural management. The identified challenges were categorized into four broad thematic areas: physical and structural, agricultural and water, socioeconomic and market, and gender and governance. A comprehensive evaluation was conducted to compare these challenges among the three irrigation schemes, different thematic areas, and various locations within each scheme (namely, the head, mid, and tail sections of the system). The findings revealed that timely access and availability of fertilizers, spring water availability and fair market prices of agricultural products are the most significant challenges. The Babai irrigation system faced the most substantial challenges among the three systems, particularly in the middle section. These findings emphasize the interconnectedness of these challenges, highlighting the need for a holistic approach to planning, implementation, and management. Integrated strategies are essential to address socioeconomic, market, and endogenous farming issues, ensuring reliable irrigation water availability for sustainable agricultural production.

A Review on Precision Agriculture: An Evolution and Prospect for the Future

A farm management system that uses information and technology to identify, analyze, and control the temporal and spatial variability within a field is known as precision farming or precision agriculture. Its goals are to maximize productivity and profitability, preserve the land resource, and minimize production costs. The public's growing environmental consciousness is forcing us to alter agricultural management techniques in order to maintain economic profitability while preserving natural resources like water, air, and soil quality. The application of inputs (such as chemical pesticides and fertilizers) in accordance with the proper amount, timing, and location. "Site-Specific Management" is the term used to describe this kind of management. With over a third of the world's food now requiring irrigation for production, the productivity increase in the global food supply has depended more and more on the expansion of irrigation schemes in recent decades. The overall economic viability of traditional agricultural systems is being challenged by market-based global competition in agricultural products, which calls for the creation of new, flexible production systems.

Validation of farmers’ on-farm irrigation scheduling for optimal water utilization in Tigray Region, Ethiopia

Unwise use of irrigation water in water-scarce areas exacerbates water scarcity, diminishes crop yield, and leads to resource wastage. In the Tigray region of Ethiopia, where water is scarce and a determinant resource, no regional-level validation of on-farm irrigation scheduling had been conducted until now. The objectives of this study were to (i) validate farmers’ irrigation scheduling practices and (ii) optimize water consumption for increased irrigated area and number of farmers. Eight different irrigation schemes were purposively selected from the Tigray region. Primary data, acquired through field measurements, observations, and discussions, were supplemented with secondary data. Farmers' irrigation scheduling practices were predominantly of the "Fixed" type, characterized by constant irrigation intervals and amounts. Unfortunately, these practices were non-optimal, with 55% over-irrigation and 45% under-irrigation. Over-irrigation instances ranged from 1350 m3in a garlic plot within the Mesima scheme to a maximum of 1,327,067 m3in a maize plot within the Serenta scheme. The excess water could potentially be utilized to irrigate an additional area of 2 to 148 hectares, thereby benefiting 7 to 296 more farmers, respectively. Conversely, instances of under-irrigation in the Fre Lekatit scheme resulted in yield reductions of 10,445 kg for potatoes and 138,499 kg for maize. In the Tigray region, most of the schemes are semi-arid, emphasizing the imperative need for water conservation. Renovating regional-level irrigation scheduling by integrating performance assessment and enhancing water productivity at the field level, and establishing a remote-sensing-based 'Real-Time Irrigation Scheduling System' is deemed necessary to sustain dryland irrigated agriculture.

Alternating water sources to minimize contaminant accumulation in food plants from treated wastewater irrigation

The use of treated wastewater (TWW) for agricultural irrigation is a critical measure in advancing sustainable water management and agricultural production. However, TWW irrigation in agriculture serves as a conduit to introduce many contaminants of emerging concern (CECs) into the soil-plant-food continuum, posing potential environmental and human health risks. Currently, there are few practical options to mitigate the potential risk while promoting the safe reuse of TWW. In this greenhouse study, the accumulation of 11 commonly occurring CECs was evaluated in three vegetables (radish, lettuce, and tomato) subjected to two different irrigation schemes: whole-season irrigation with CEC-spiked water (FULL), and half-season irrigation with CEC-spiked water, followed by irrigation with clean water for the remaining season (HALF). Significant decreases (57.0–99.8 %, p < 0.05) in the accumulation of meprobamate, carbamazepine, PFBS, PFBA, and PFHxA in edible tissues were found for the HALF treatment with the alternating irrigation scheme. The CEC accumulation reduction was attributed to reduced chemical input, soil degradation, plant metabolism, and plant growth dilution. The structural equation modeling showed that this mitigation strategy was particularly effective for CECs with a high bioaccumulation potential and short half-life in soil, while less effective for those that are more persistent. The study findings demonstrate the effectiveness of this simple and on-farm applicable management strategy that can be used to minimize the potential contamination of food crops from the use of TWW and other marginal water sources in agriculture, while promoting safe reuse and contributing to environmental sustainability.

Incorporating Spatio-Temporal Changes of Well Irrigation into a Distributed Hydrologic Model to Improve Groundwater Anomaly Estimations for Basins with Expanding Agricultural Lands

AbstractThis paper seeks to address the deficiency of utilizing satellite-based GRACE observations and model-based GLDAS water budget components in estimating the changes in the groundwater storage in Konya Endorheic Basin (KEB), a basin experiencing considerable land use land cover (LULC) change, primarily agricultural expansion. Cereal cultivation in the basin has a slight decreasing trend, however, the cultivation of crops with high water consumption, such as maize and sunflower, is increasing substantially. And total agricultural areas are increasing. GRACE-GLDAS approach does not accurately give the long-term groundwater decline in the basin, mainly because the land surface models employed in GLDAS cannot realistically simulate variations in water budget components as they do not consider the changes in LULC and do not possess an elaborated irrigation scheme. Here, we used a fully-distributed mesoscale hydrologic model, mHM, that can handle multiple LULC maps from different years. The model was modified to incorporate the spatio-temporal changes of agricultural fields in KEB and an explicit irrigation scheme since we hypothesized that the groundwater depletion is mainly caused by well irrigation. mHM was calibrated against streamflow observations for the period 2004–2019. The simulations show that the use of mHM with the incorporated features gives groundwater storage changes that are more consistent with the well-based observations than those obtained from the GRACE-GLDAS approach. On the other hand, the mHM simulation with a static LULC map, as in GLDAS models but with a better representation of irrigated fields, provides groundwater anomaly changes that are more consistent with the GRACE-GLDAS results, a further justification of insufficiency of the GLDAS-based approach in estimating groundwater variations for basins with considerable landscape change.

A Study on Groundwater Irrigation Expansion in Bihar, India

Water use has increased by more than twice the rate of population growth over the past century. Although, there is worldwide water scarcity, an increasing number of areas are chronically short of water. There has been a substantial increase in irrigated areas in the last thirty -five years. The Net Irrigated Area (NIA) in Bihar has increased from 2808 thousand hectares in 1985 to 3083 thousand hectares in 2021. The total annual replenishable groundwater potential of Bihar has been estimated as 33.15 billion cubic meters (bcm) with an annual extraction of 13.50 bcm. The share of surface water is declining while groundwater is increasingly being used in crop production. A total of 11754 thousand hectares have been estimated as the ultimate irrigation potential in the state, including major, medium and minor irrigation schemes, utilizing both surface and groundwater. If the available potential is fully exploited, it can cover more than the total cultivated area of the state. Considering the interests of both present and future generations attention needs to be directed towards the sustainable use of groundwater and promoting various sources of surface water.

Analysis of heavy metals and pathogen levels in vegetables cultivated using selected water bodies in urban areas of the Greater Accra Metropolis of Ghana

Open-surfaced water sources have been used to irrigate vegetable farms in cities. Open-surface water often contains unmonitored concentrations of health-threatening contaminants that pose health risks, especially when used to produce vegetables for human consumption. However, information on levels of heavy metals and faecal coliform bacteria in such vegetables in selected sites, especially in Greater Accra Metropolitan Area (GAMA) of Ghana is rare. This study examines the levels of heavy metals and faecal coliform in two vegetables-lettuce and bell pepper - that were cultivated using open-surface wastewater from drains and constructed reservoirs at different locations of the GAMA. Using concurrent mixed methods, questionnaires were administered to 67 vegetable farmers, followed by the collection of vegetable samples from three urban farm sites, Haatso and Dzorwulu and Weija irrigation scheme site (WISS) for laboratory analysis. The concentrations of Lead (Pb), Mercury (Hg) and Cadmium (Cd) were determined using atomic absorption spectroscopy after microwave digestion of the vegetables while total faecal coliform was quantified using MacConkey-Endo broth method. The results from all three sites showed that the concentrations of Cd (=0.001 μg/mg) and Pb (=0.005 μg/mg) in lettuce were within the World Health Organization's (WHO) permissible levels. However, the Hg (≥0.309 μg/mg) and faecal coliform (>5 count/100 ml) in the vegetables from all three sites exceeded the WHO permissible limits. Therefore, consumers of vegetables from such urban farms are exposed to health risks associated with Hg and faecal coliforms. There is the need to intensify education on the health risks of consuming vegetables produced from open-surface water sources from the observed sites. The enforcement of existing phytosanitary standards to enhance food safety and the quality of urban vegetables is also recommended.

Using Principal Component Analysis to Assess Soil Chemical Properties in the Mwea Irrigation Scheme, Kenya: Implications for Rice Agronomic Management

Sub-Saharan Africa faces significant challenges as a net importer of rice, with self-sufficiency rates plummeting to as low as 14% in countries like Kenya. The Mwea irrigation scheme shoulders the bulk of rice cultivation, contributing over 80% of the country’s production. However, productivity within the scheme has seen a concerning decline, dropping from 5.6 ─ 6.0 t ha-1 to 1.3 ─ 4.6 t ha-1 between 1977 and 2018. This decline could be attributed to site-specific nutritional deficiencies and/or toxicities, rendering generalized agronomic recommendations ineffective in certain areas. To address this problem, our study aimed to assess soil chemical properties variability within the Mwea irrigation scheme, identify clusters with similar nutritional status, and tailor area-specific agronomic recommendations. During May to September 2020, we collected and analyzed four hundred samples from five sections of the scheme for total organic carbon, soil pH, macro and micronutrients, and exchangeable cations. Principal component analysis was conducted on the mean values of the soil chemical properties to identify significant contributors to variation and establish zones with similar patterns. Principal components 1 to 4 collectively explained 72.2% of the total variability. Cluster analysis revealed four distinct clusters, namely MW, TB, KT, and MU. Within cluster MW, soil pH was below the optimum range for rice cultivation, suggesting a need for liming. Potassium deficiency was observed across all clusters, with rice straw incorporation recommended as a long-term solution. Furthermore, zinc deficiency was noted in cluster WU, necessitating zinc fertilizer application. Conversely, iron toxicity was a concern in cluster MW, suggesting the adoption of alternating wetting and drying techniques and cultivating tolerant varieties. By proving tailored recommendations based on localized soil conditions, we aim to bolster rice productivity within the Mwea irrigation scheme and contribute to regional food security efforts.

Developing a New ANN Model to Estimate Daily Actual Evapotranspiration Using Limited Climatic Data and Remote Sensing Techniques for Sustainable Water Management

Accurate estimations of actual evapotranspiration (ETa) are essential to various environmental issues. Artificial intelligence-based models are a promising alternative to the most common direct ETa estimation techniques and indirect methods by remote sensing (RS)-based surface energy balance models. Artificial Neural Networks (ANNs) are proven to be suitable for predicting reference evapotranspiration (ETo) and ETa based on RS data. This study aims to develop a methodology based on ANNs for estimating daily ETa values using NDVI and land surface temperature, coupled with limited site-specific climatic variables in a large irrigation catchment. The ANN model has been applied to the two different scenarios. Data from only the 38 days of satellite overpass dates was selected in Scenario I, while in Scenario II all datasets, i.e., the 769-day data were used. An irrigation scheme, located in the Mediterranean region of Turkiye, was selected, and a total of 38 Landsat images and local climatic data collected in 2021 and 2022 were used in the ANN model. The ETa results by the ANN model for Scenarios I and II showed that the R2 values for training (0.79 and 0.86), testing (0.75 and 0.81), and the entire dataset (0.76 and 0.84) were all remarkably high. Moreover, the results of the new ANN model in two scenarios showed an acceptable agreement with ETa-METRIC values. The proposed ANN model demonstrated the potential for obtaining daily ETa using limited climatic data and RS imagery. As a result, the suggested ANN model for daily ETa computation offers a trustworthy way to determine crop water usage in real time for sustainable water management in agriculture. It may also be used to assess how crop evapotranspiration in drought-prone areas will be affected by climate change in the 21st century.

Validation of a new global irrigation scheme in the land surface model ORCHIDEE v2.2

Abstract. Irrigation activities are important for sustaining food production and account for 70 % of total global water withdrawals. In addition, due to increased evapotranspiration (ET) and changes in the leaf area index (LAI), these activities have an impact on hydrology and climate. In this paper, we present a new irrigation scheme within the land surface model ORCHIDEE (ORganising Carbon and Hydrology in Dynamic EcosystEms)). It restrains actual irrigation according to available freshwater by including a simple environmental limit and using allocation rules that depend on local infrastructure. We perform a simple sensitivity analysis and parameter tuning to set the parameter values and match the observed irrigation amounts against reported values, assuming uniform parameter values over land. Our scheme matches irrigation withdrawals amounts at global scale, but we identify some areas in India, China, and the USA (some of the most intensively irrigated regions worldwide), where irrigation is underestimated. In all irrigated areas, the scheme reduces the negative bias of ET. It also exacerbates the positive bias of the leaf area index (LAI), except for the very intensively irrigated areas, where irrigation reduces a negative LAI bias. The increase in the ET decreases river discharge values, in some cases significantly, although this does not necessarily lead to a better representation of discharge dynamics. Irrigation, however, does not have a large impact on the simulated total water storage anomalies (TWSAs) and its trends. This may be partly explained by the absence of nonrenewable groundwater use, and its inclusion could increase irrigation estimates in arid and semiarid regions by increasing the supply. Correlation of irrigation biases with landscape descriptors suggests that the inclusion of irrigated rice and dam management could improve the irrigation estimates as well. Regardless of this complexity, our results show that the new irrigation scheme helps simulate acceptable land surface conditions and fluxes in irrigated areas, which is important to explore the joint evolution of climate, water resources, and irrigation activities.

Assessment of Irrigation Water Management Performance Indicators and Mitigation Measure in Arba Minch Irrigation Scheme, Ethiopia

Assessment of Irrigation Water Management Performance Indicators and Mitigation Measure in Arba Minch Irrigation Scheme, Ethiopia

Analysis of the social and physical factors affecting irrigation scheme performance: The case of the Omo Gibe river basin in the Southern Nations, Nationalities and Peoples’ Region, Ethiopia

AbstractOne hundred years ago, irrigation development began in Ethiopia, but the efficiency and sustainability of the developed scheme have remained very low. As a result, this study aimed to assess the factors that most frequently affect a scheme's performance. The study analysed general physical and social performance indicators. Structural and social factors were used to identify the most common causes of underperformance of the schemes in the Omo Gibe river basin. Frequency analysis was conducted using Statistical Package for the Social Sciences (SPSS). The relative operational scheme performance and relative irrigated area were 32 and 31%, respectively. The beneficiary to target performance was 63%. Structural and social factors such as flooding and subsequent damage to the under sluice and lack of participatory approaches during scheme development were the most common determinants of irrigation scheme performance. Hence, catchment development and community participation in scheme development are crucial for mitigating irrigation scheme underperformance.