Irrigation Expansion Research Articles

Modeling surface water potential and allocating water demand in the Nashe River watershed using water evaluation and planning

ABSTRACT The Nashe River watershed in Ethiopia is experiencing increased water demand due to the growing socioeconomic activities. As a result, the study aimed to assess the surface water potential and allocate water demands in the Nashe watershed, Ethiopia, by utilizing the water evaluation and planning model. The model was calibrated using observed and simulated streamflow data, resulting in a good performance with a Nash–Sutcliffe efficiency of 0.955, a coefficient of determination (R2) of 0.952, and a percentage of bias of −2.859. In the base year (2019), the annual surface runoff was estimated at 1.197 billion cubic meters (BCM), while the current annual water demand is 328.35 million cubic meters (MCM), indicating no water shortage currently. However, future scenario analysis considering a 3.9% annual irrigation expansion showed an increase in irrigation water demand from 0.30076 MCM in the base year to 0.984 MCM by 2050. Additionally, a scenario analyzing natural climate variation indicated a decrease in available surface water resources, ranging from 1.197 BCM during a normal year to 0.267 BCM during a very dry year. The study revealed that there will be unmet water demand during dry months and excess water demand during wet months.

Contrasting impacts of irrigation and deforestation on Lancang-Mekong River Basin hydrology

Irrigation expansion and subsequent deforestation substantially affect large basin variability. However, given the complex interactions between hydrological variables, a more comprehensive understanding of the hydrological impacts within the coexisting land use changes is needed. Here, we applied surface-groundwater-coupled simulations with historical river gauges and satellite observations to evaluate long-term and seasonal changes in Lancang-Mekong River Basin hydrology. Increasing irrigation elevated soil moisture but depleted groundwater storage. Conversely, deforestation reduced soil moisture, and increased lateral flow in areas with steep terrain compensated for groundwater depletion. Irrigation affected runoff by augmenting evapotranspiration and baseflow, which had opposite implications for runoff changes, causing a mixed spatial pattern of decreases and increases. Meanwhile, decreases in soil moisture due to deforestation offset increases in evapotranspiration due to irrigation, resulting in wider areas of runoff increases than decreases. These illustrate the distinct hydrological impacts of different land use changes and a pathway to complex system assessments.

Impacts of irrigation expansion on moist-heat stress based on IRRMIP results

Irrigation rapidly expanded during the 20th century, affecting climate via water, energy, and biogeochemical changes. Previous assessments of these effects predominantly relied on a single Earth System Model, and therefore suffered from structural model uncertainties. Here we quantify the impacts of historical irrigation expansion on climate by analysing simulation results from six Earth system models participating in the Irrigation Model Intercomparison Project (IRRMIP). Results show that irrigation expansion causes a rapid increase in irrigation water withdrawal, which leads to less frequent 2-meter air temperature heat extremes across heavily irrigated areas (≥4 times less likely). However, due to the irrigation-induced increase in air humidity, the cooling effect of irrigation expansion on moist-heat stress is less pronounced or even reversed, depending on the heat stress metric. In summary, this study indicates that irrigation deployment is not an efficient adaptation measure to escalating human heat stress under climate change, calling for carefully dealing with the increased exposure of local people to moist-heat stress.

Irrigation Expansion and Rural Transformation in China: Evidence of Provincial Data in 1978–2018

ABSTRACTThe role of irrigation expansion in facilitating rural transformation has been widely documented, yet quantitative studies remain rather limited. Based on the statistical data from 27 provinces in China, this paper analyses the correlation between irrigation expansion and rural transformation over the period of 1978–2018. The econometric results indicate a positive relationship between irrigation expansion and high‐value agriculture. However, from a dynamic perspective, for each percentage point increase in the share of cultivated land with irrigation, the share of high‐value agriculture decreases by 0.09 percentage points in the early stage, but increases by 0.07 and 0.12 percentage points in the subsequent middle and later stages, respectively. Likewise, the relationship between irrigation expansion and non‐farm employment of rural labourers is not always negative. Specifically, an additional one percentage point increase in the share of cultivated land with irrigation is associated with a 0.09 percentage points decline in the share of rural labour non‐farm employment in the early stage. This reduction moderates to a 0.05 percentage points in the middle stage, but there is a 0.08 percentage points increase in the later stage. This paper further concludes with several implications for policymakers and academic research.

Drivers of global irrigation expansion: the role of discrete global grid choice

Abstract. Global statistical irrigation modeling relies on geospatial data and traditionally adopts a discrete global grid based on longitude–latitude reference. However, this system introduces area distortion, which may lead to biased results. We propose using the ISEA3H geodesic grid based on hexagonal cells, enabling efficient and distortion-free representation of spherical data. To understand the impact of discrete global grid choice, we employ a non-parametric statistical framework, utilizing random forest methods, to identify the main drivers of historical global irrigation expansion using, among other data, outputs from the global dynamic vegetation model Lund-Potsdam-Jena managed Land (LPJml). Irrigation is critical for food security amidst growing populations, changing consumption patterns, and climate change. It significantly boosts crop yields but also alters the water cycle and global water resources. Understanding past irrigation expansion and its drivers is vital for global change research, resource assessment, and the prediction of future trends. We compare predictive accuracy, simulated irrigation patterns, and identification of irrigation drivers between the two grid systems. Using the ISEA3H geodesic grid system increases the predictive accuracy by up to 28 % compared to the longitude–latitude grid. The model identifies population density, potential productivity increase, evaporation, precipitation, and water discharge as key drivers of historical global irrigation expansion. Gross domestic product (GDP) per capita also shows some influence. We conclude that the geodesic discrete global grid system significantly affects predicted irrigation patterns and identification of drivers and thus has the potential to enhance statistical modeling, which warrants further exploration in future research across related fields. This analysis lays the foundation for comprehending historical global irrigation expansion.

Beer, barley, livestock, milk: Who adopts agricultural innovations in rural Rajasthan?

Research conducted in developing countries in the past 50 years generally suggests that most agricultural innovations (whether technological, social, or financial in nature) end up reinforcing existing socio-economic hierarchies based on gender and class. Most of these findings are drawn from the Green Revolution, which focused overwhelmingly on high-yielding varieties of rice, maize, and wheat, along with the introduction or expansion of irrigation and extension services and the use of fertilizers and pesticides. Less is known about how agricultural innovations involving other crops or livestock, especially if introduced in tandem, perform in alleviating poverty or reducing gender inequality. We conducted a study in three agricultural communities in rural Rajasthan, India to understand how the adoption of agricultural innovations for barley cultivation and livestock rearing are influenced by the gender, age, and class background of farmers, and whether such innovations can alleviate poverty and promote gender equality in rural settings. We found that although innovation adoption is influenced by gender, class and age (with gender exerting a stronger influence than class or age), poorer farmers and women can under certain circumstances benefit from agricultural innovations adopted initially by wealthier male farmers.

Puzzlingly low utilization of solar irrigation pumps by smallholders in Nepal undermines cost-effectiveness

Abstract Solar Powered Irrigation Pumps (SIPs) hold substantial potential for low carbon irrigation expansion, particularly where affordable electricity is limited. In contrast to diesel-based irrigation, which carries steep fuel costs, irrigation by SIPs requires zero marginal costs, but high initial investments. This makes their competitiveness with diesel pumps highly dependent on the temporal frequency of their usage. Using unique and detailed data on SIP usage by smallholders in Nepal, we show SIP usage frequency is low, making it financially competitive with Diesel for only a small fraction of farmers. We analyze characteristics of farmers who make low/high usage of the SIP, and explore potential explanations for the puzzling low level of SIP use.

Sustainable land and irrigation management to limit loss of hydropower in the Andes-Amazon headwaters

Water plays a critical role in adapting food and energy systems to climate change in the Andes. However, robust climate solutions that work across sectors have not been explored for these working landscapes. Here we develop a framework consisting of high-fidelity catchment and hydropower models while considering climate and other uncertainties in a robust, bottom-up manner for the upper Huallaga River in Peru. We then explore adaptation strategies across sectors. Our results highlight that irrigation will be critical for maintaining food production under climate change. Yet, an unplanned expansion of irrigation could lead to a near total loss of firm hydropower downstream. Exploring 10,080 possible landuse/management adaptation pathways, we find limited opportunities for win-win solutions under climate change. In the light of such challenges, our results highlight the need for navigating structural trade-offs between upstream land and water users and downstream interests in the Andes in a strategic and equitable manner.

Water demand and supply under future water development and climate change scenarios in the upper Blue Nile basin

ABSTRACT Integrated methodological approaches to analyzing water demand and supply under changing scenarios in a river basin are crucial for managing water resources. To better understand the influence of socioeconomic and climate change on water supply, this study employed an integrated methodological approach that included the soil and water assessment tool (SWAT) hydrology and the water evaluation and planning (WEAP) models. Water development scenarios were created for two time periods: near future (2021–2040) and full development (2041–2060). During the current account period, water for irrigation delivery was balanced, and existing hydropower facilities generated energy at full capacity (3,159 GWh). However, irrigation water supply in the near future and full development scenarios shows a shortfall (267 Mm3 and 594 Mm3 under RCP4.5, and 213 Mm3 and 611 Mm3 under RCP8.5, respectively). Despite the basin's energy production will increase during the scenario periods, under-construction and planned hydropower plants are predicted to operate at less than full capacity (44,921 GWh under RCP4.5 and 44,539 GWh under RCP8.5). The study concluded that climate change-induced water availability and irrigation expansion would contribute to the water supply-demand mismatch. As a result, water resource management is required to increase water availability, minimize water demand, and reduce unmet demand.

Enhancing irrigation development and expansion through accurate spatial information of irrigated areas

Enhancing irrigation development and expansion through accurate spatial information of irrigated areas

Establishing the water resources implications for closing the land and water productivity gaps using remote sensing – A case study of sugarcane

Establishing the water resources implications for closing the land and water productivity gaps using remote sensing – A case study of sugarcane

Energy models in service of aquifer specific groundwater irrigation expansion in India

Abstract Pumping energy is a key component of the groundwater governance challenge, yet it is largely missing in the discourse on agricultural use of groundwater. A sub-category of literature studying groundwater-energy nexus tends to focus on groundwater depletion hotspots where entrenched interests and long-standing histories restrict the range of feasible energy pricing options. Using an agent based model, we estimate expected impacts of expanding groundwater irrigation under five different energy provision models in Odisha, an Indian state with among the lowest irrigation coverage, and therefore, free of path dependent policies. We find aquifer properties play a crucial role in mediating the groundwater-energy nexus. For this study region, on average, the maximum volume of water that can be pumped from a well of a specific depth in an alluvial aquifer is approximately 150 times the volume that can be pumped from a well in a hard-rock aquifer. Therefore, the risk of over-consumption and aquifer depletion is a far greater challenge in alluvial than hard-rock aquifers. Risks of groundwater consumption and depletion can be limited in hard-rock aquifers provided the number and depths of wells can be controlled. Capital subsidies for well construction could be an effective policy to increase irrigated area so long as economic incentives for digging deeper are not distorted. Our results imply that solar pumps are a relatively safe option for hard-rock regions where deep drawdowns naturally limit the extent of over-extraction. Solar pumps are also estimated to be among the most economical for expanding irrigation. Using a novel dataset comprising of biophysical and socioeconomic data, we find hard-rock regions to have limited irrigation coverage, high availability of annually replenishable groundwater, and high concentrations of marginalized farmers. Therefore, groundwater irrigation expansion in hard-rock areas could have dual benefits of ensuring future food security and targeting poverty reduction.

Identification of groundwater potential zones using geospatial technologies in Meki Catchment, Ethiopia

ABSTRACT Mapping groundwater potential zones helps in precisely planning well drilling. The Meki Catchment is currently experiencing irrigation expansion and water scarcity challenges, creating a strong need for groundwater exploitation. The goal of this study was to identify groundwater potential zones (GWPZs) in the Meki Catchment using geospatial technologies to enhance water resource management and support sustainable development in the region. Eight thematic components were used in this analysis. Analytical Hierarchy Process (AHP) method was applied to ensure consistency in judgments through paired comparisons. Weighted overlay analysis was then used to evaluate the GWPZs. The study found that out of the total Meki Catchment area (226,333.26 ha), 30.68% (69,448.31 ha) has high potential, and 34% (76,963.33 ha) has good potential. Validation was conducted using ground truth data, considering existing water point field data from borewells and springs. The results of this study can help prioritize strategies to ensure the sustainable use of groundwater in the area. Drilling organizations can utilize these findings as a resource for feasibility studies in groundwater prospecting projects to locate well sites. The validation results demonstrate that potential groundwater zones can be identified more accurately using GIS and RS approaches at a lower cost.

Leveraging atmospheric moisture recycling in Saudi Arabia and neighboring countries for irrigation and afforestation planning

Effective irrigation planning is crucial for sustainable agricultural development and ecosystem restoration projects in arid regions. With respect to ambitious greening initiatives, Saudi Arabia is establishing a national strategy toward a more sustainable and eco-friendly future not only for itself but also for the broader Middle East region. Thus, comprehensively understanding the water cycle in the region is essential to identify the most suitable target locations for afforestation and reforestation while considering the potential role of irrigation. Herein, in addition to traditional pedoclimatic factors, we introduce a complementary consideration—“irrigation recycling.” Building on the well-established concept of atmospheric moisture recycling and taking advantage from an atmospheric trajectory dataset, we track the path of evaporated water from current or potential irrigated sites to the location where the evaporated water eventually falls as precipitation. Our analysis offers two key benefits. First, it helps pinpoint the regions in which and the periods during which water recycling is maximum within the country, aiding more precise calculations of the investment return value for irrigation infrastructures. Second, it helps identify the land-use change patterns that contribute to international efforts such as drought mitigation in East Africa as an example. We found that one-third of the actual precipitation in the current Saudi irrigated sites originated from evapotranspiration over land, mainly from Saudi Arabia and surrounding countries. Interestingly, most of the evapotranspiration from these irrigated sites will eventually fall somewhere over land (primarily in Iran). Controlling the seasonality and spatial distribution of the future irrigation expansion will allow controlling the atmospheric moisture recirculation in Saudi Arabia and nearby drought-prone regions such as Eastern Africa. The outcomes of this study will be the subject of future integrated assessments to account for the climatic feedbacks of the land-use change scenarios. At present, they provide crucial insights to support the decision-making process surrounding the Saudi and Middle East Green Initiatives. Further, the presented methodology offers a pragmatic framework that can be applied to similar greening projects for other regions, making it a viable and valuable approach for global sustainability programs.

Irrigation expansion in the face of war and climate change.

Irrigation expansion in the face of war and climate change.

Blinded like a state: Water scarcity and the quantification dilemma in Morocco

Blinded like a state: Water scarcity and the quantification dilemma in Morocco

Why Do Farmers Not Irrigate All the Areas Equipped for Irrigation? Lessons from Southern Africa.

The reliance on rainfed agriculture exposes southern Africa to low agricultural productivity and food and nutritional insecurity; yet, the region is endowed with vast irrigation potential. Extreme weather events including drought, floods, and heatwaves exacerbate the existing challenges, underscoring the need to improve agricultural water management as a climate change adaptation strategy. This mixed-methods review followed the Search, Appraisal, Synthesis, and Analysis (SALSA) framework to explore the irrigation opportunities and challenges in southern Africa by critically analysing the drivers and constraints of irrigation systems in southern Africa. The premise is to understand the reasons behind the abandonment of some of the areas equipped for irrigation. In cases where irrigation systems are present, the study assesses whether such technologies are effectively being used to generate the expected agricultural productivity gains, and what factors, in cases where that is not the case, constrain farmers from fully using the existing infrastructure. The review further discusses the enabling environment supporting irrigated agriculture and the role of gender in irrigation development. An assessment of the role of women in agriculture on the share of land equipped for irrigation to total cultivated land area, as well as on the proportion of the area equipped for irrigation versus the area that is actually irrigated is conducted. The review found a divergence between countries' land areas equipped for irrigation and actually irrigated areas. Specific to irrigation expansion, the review rebuts the notion that increasing the irrigated area increases crop production and ensures food security. This may not always be true as irrigation development needs to consider the impacts on other closely linked water and energy sectors through transformative approaches like the water-energy-food (WEF) nexus and scenario planning. If well-planned and implemented, sustainable irrigated agriculture could be catalytic to transforming southern Africa's food system to be inclusive, equitable, socially just, and resilient, benefiting people and the planet.

Regional irrigation expansion can support climate-resilient crop production in post-invasion Ukraine.

Ukraine supplies a large proportion of grain and oilseeds to the world market and faces disruptions from the Russian invasion in 2022. Here we explore the combined effects of the invasion and climate change on Ukraine's irrigation. In 2021, only 1.6% of Ukraine's cropland was irrigated. Of this portion, 73% experienced substantial declines in irrigated crop production following the invasion. We estimate that by the mid-twenty-first century, three-quarters of croplands will experience water shortages, making business-as-usual rain-fed agricultural practices inadequate in addressing the challenges posed by climate change. We explore how leveraging local surface and groundwater resources could enable sustainable irrigation expansion over 18 million hectares of croplands and form a viable climate adaptation strategy. Finally, we identify regions for implementing enhancements or expansions of irrigation systems that can foster a more resilient agricultural sector-underscoring the growing importance of irrigation in sustaining crop production in Ukraine.

Irrigation expansion shows potential for increased maize yield and reduced nitrogen leaching in the Midwest US

Irrigation expansion shows potential for increased maize yield and reduced nitrogen leaching in the Midwest US

Forest management for water yield: Assessing the barriers and impacts of privately-owned open pine woodlands in the Southeastern United States

Forest management for water yield: Assessing the barriers and impacts of privately-owned open pine woodlands in the Southeastern United States