Ministry of Water Resources and Irrigation

A brief history of development of the 1985 Hargreaves equation and its comparison to evapotranspiration (ET) predicted by the Food and Agricultural Organization of the United Nations (FAO) Penman-Monteith method are described to provide background and information helpful in selecting an appropriate reference ET equation under various data situations. Early efforts in irrigation water requirement computations in California and other arid and semiarid regions required the development of simplified ET equations for use with limited weather data. Several initial efforts were directed towards improving the usefulness of pan evaporation for estimating irrigation water requirements. Similarity with climates of other countries allowed developments in California to be extended overseas. Criticism of empirical methods by H. L. Penman and others encouraged the search for a robust and practical method that was based on readily available climatic data for computing potential evapotranspiration or reference crop evapotranspiration (ETo). One of these efforts ultimately culminated in the 1985 Hargreaves ETo method. The 1985 Hargreaves ETo method requires only measured temperature data, is simple, and appears to be less impacted than Penman-type methods when data are collected from arid or semiarid, nonirrigated sites. For irrigated sites, the Hargreaves 1985 ETo method produces values for periods of five or more days that compare favorably with those of the FAO Penman-Monteith and California Irrigation Management Information Services (CIMIS) Penman methods. The Hargreaves ETo predicted 0.97 of lysimeter measured ETo at Kimberly, Idaho after adjustment of lysimeter data for differences in surface conductance from the FAO Penman-Monteith definition. Monthly ETo by the 1985 Hargreaves equation compares closely with ETo calculated using a simplified, “reduced-set” Penman-Monteith that requires air temperature data only.

Abstract When a fluid containing a tracer in solution is displaced from a porous medium by the same fluid without a tracer, this miscible displacement results in a tracer concentration distribution which depends upon microscopic flow velocities, tracer diffusion rates and other chemical and physical processes. Miscible displacement has been studied in several porous materials under saturated and unsaturated conditions at different average flow velocities. The tracer appeared at the end of the soil column well in advance of that expected had no mixing occurred at the boundary of the tracer and tracer‐free water. Physical differences between porous materials were manifested by changes in shape and position of breakthrough curves owing to ionic diffusion. One of the more important physical features was the magnitude of the volume of water not readily displaced at saturation and its increase when the soil was desaturated. Because the total flux of water moving through field soils is generally small, the role played by hydrodynamic dispersion and diffusion in transporting dissolved solutes must be included in the theory of most soil‐water processes.

Abstract Several theoretical models are examined as to their usefulness in describing miscible displacement in porous materials. These descriptions are discussed for glass beads, sieved aggregates and soils at several water contents and for several flow velocities. It is shown that mathematical descriptions which do not include individual mechanisms are unsatisfactory. The mechanisms that must be considered are discussed with specific reference to experimental data.

Abstract. This study analyses the output of 17 general circulation models (GCMs) included in the 4th IPCC assessment report. Downscaled precipitation and potential (reference crop) evapotranspiration (PET) scenarios for the 2081–2098 period were constructed for the upper Blue Nile basin. These were used to drive a fine-scale hydrological model of the Nile Basin to assess their impacts on the flows of the upper Blue Nile at Diem, which accounts for about 60% of the mean annual discharge of the Nile at Dongola. There is no consensus among the GCMs on the direction of precipitation change. Changes in total annual precipitation range between −15% to +14% but more models report reductions (10) than those reporting increases (7). Several models (6) report small changes within 5%. The ensemble mean of all models shows almost no change in the annual total rainfall. All models predict the temperature to increase between 2°C and 5°C and consequently PET to increase by 2–14%. Changes to the water balance are assessed using the Budyko framework. The basin is shown to belong to a moisture constrained regime. However, during the wet season the basin is largely energy constrained. For no change in rainfall, increasing PET thus leads to a reduced wet season runoff coefficient. The ensemble mean runoff coefficient (about 20% for baseline simulations) is reduced by about 3.5%. Assuming no change or moderate changes in rainfall, the simulations presented here indicate that the water balance of the upper Blue Nile basin may become more moisture constrained in the future.

The Imperial Irrigation District is a large irrigation project in the western United States having a unique hydrogeologic structure such that only small amounts of deep percolation leave the project directly as subsurface flows. This structure is conducive to relatively accurate application of a surface water balance to the district, enabling the determination of crop evapotranspiration (ETc) as a residual of inflows and outflows. The ability to calculate ETc from discharge measurements provides the opportunity to assess the accuracy and consistency of an independently applied crop coefficient—reference evapotranspiration (KcET0) procedure integrated over the project. The accuracy of the annual crop evapotranspiration via water balance estimates was ±6% at the 95% confidence level. Calculations using Kc and ET0 were based on the FAO-56 dual crop coefficient approach and included separate calculation of evaporation from precipitation and irrigation events. Grass reference ET0 was computed using the CIMIS Penman equation and ETc was computed for over 30 crop types. On average, Kc -based ET computations exceeded ETc determined by water balance (referred to as ETcWB ) by 8% on an annual basis over a 7 year period. The 8% overprediction was concluded to stem primarily from use of Kc that represents potential and ideal growing conditions, whereas crops in the study area were not always in full pristine condition due to various water and agronomic stresses. A 6% reduction to calculated Kc -based ET was applied to all crops, and a further 2% reduction was applied to lower value crops to bring the project-wide ET predicted by Kc -based ET into agreement with ETcWB . The standard error of estimate (SEE) for annual ETc for the entire project based on Kc , following the reduction adjustment, was 3.4% of total annual ETc , which is considered to be quite good. The SEE for the average monthly ETc was 15% of average monthly ETc . A sensitivity analysis of the computational procedure for Kc showed that relaxation from using the FAO-56 dual Kc method to the more simple mean (i.e., single) Kc curve and relaxation of specificity of planting and harvest dates did not substantially increase the projectwide prediction error The use of the mean Kc curves, where effects of evaporation from wet soil are included as general averages, predicted 5% lower than the dual method for monthly estimates and 8% lower on an annual basis, so that no adjustment was required to match annual ET derived from water balance. About one half of the reduction in estimates when applying the single (or mean) Kc method rather than the dual Kc method was caused by the lack of accounting for evaporation from special irrigations during the off season (i.e., in between crops).

Abstract It is of interest to know the microscopic flow velocity distribution of water moving through soil. Dissolved constituents frequently have been used to trace water movement in porous materials. It is apparent from this and previous investigations, that the distribution of a tracer some distance from its source, depends upon the geometry of the porous material and the physical and chemical interaction of the tracer solution and media during flow. Therefore, investigators studying water movement using tracers are compelled to ascertain the importance of the interaction of tracer solution in the media. Tritium and chloride ion were used as tracers for water flowing under stationary conditions in laboratory soil columns. The distribution of the tracers measured in the effluent is explained on the basis of the relative effects of pore geometry, diffusion rates, adsorption and exchange.

Analysis the water–food–energy nexus is the first step to assess the decision maker in developing and evaluating national strategies that take into account the nexus. The main objective of the current research is providing a method for the decision makers to analysis the water–food–energy nexus of the crop production system at the national level and carrying out a quantitative assessment of it. Through the proposed method, indicators considering the water and energy consumption, mass productivity, and economic productivity were suggested. Based on these indicators a water–food–energy nexus index (WFENI) was performed. The study showed that the calculated WFENI of the Egyptian summer crops have scores that range from 0.21 to 0.79. Comparing to onion (the highest scoring WFENI,i.e., the best score), rice has the lowest WFENI among the summer food crops. Analysis of the water–food–energy nexus of forty-two Egyptian crops in year 2010 was caried out (energy consumed for irrigation represent 7.4% of the total energy footprint). WFENI can be applied to developed strategies for the optimal cropping pattern that minimizing the water and energy consumption and maximizing their productivity. It can be applied as a holistic tool to evaluate the progress in the water and agricultural national strategies. Moreover, WFENI could be applied yearly to evaluate the performance of the water-food-energy nexus managmant.

Abstract There is a weak evidence base supporting the effective management of riparian ecosystems within tropical agriculture. Policies to protect riparian buffers—strips of non‐cultivated land alongside waterways—are vague and vary greatly between countries. From a rapid evidence appraisal, we find that riparian buffers are beneficial to hydrology, water quality, biodiversity and some ecosystem functions in tropical landscapes. However, effects on connectivity, carbon storage and emissions reduction remain understudied. Riparian functions are mediated by buffer width and habitat quality, but explicit threshold recommendations are rare. Policy implications . A one‐size fits all width criterion, commonly applied, will be insufficient to provide all riparian functions in all circumstances. Context‐specific guidelines for allocating, restoring and managing riparian buffers are necessary to minimise continued degradation of biodiversity and ecosystem functioning in tropical agriculture.

Abstract A critical discussion of recent studies that analysed the effects of climate change on the water resources of the River Nile Basin (RNB) is presented. First, current water-related issues on the RNB showing the particular vulnerability to environmental changes of this large territory are described. Second, observed trends in hydrological data (such as temperature, precipitation, river discharge) as described in the recent literature are presented. Third, recent modelling exercises to quantify the effects of climate changes on the RNB are critically analysed. The many sources of uncertainty affecting the entire modelling chain, including climate modelling, spatial and temporal downscaling, hydrological modelling and impact assessment are also discussed. In particular, two contrasting issues are discussed: the need to better recognize and characterize the uncertainty of climate change impacts on the hydrology of the RNB, and the necessity to effectively support decision-makers and propose suitable adaptation strategies and measures. The principles of a code of good practice in climate change impact studies based on the explicit handling of various sources of uncertainty are outlined. Citation Di Baldassarre, G., Elshamy, M., van Griensven, A., Soliman, E., Kigobe, M., Ndomba, P., Mutemi, J., Mutua, F., Moges, S., Xuan, J.-Q., Solomatine, D. & Uhlenbrook, S. (2011) Future hydrology and climate in the River Nile basin: a review. Hydrol. Sci. J. 56(2), 199–211.

Background and Objective: Salinity either saline water of irrigation or saline soil is considered a major factor in limiting plant growth. Nano fertilizers are used to reduce drastic effect of salinity. This study was performed to limit salinity drastic effect on plant productivity and to study the effect of SiO 2 nano fertilizers foliar spray on growth parameter, yield, chemical composition of cucumber (Cucumis sativa) grown under agricultural drainage water. Materials and Methods: A field experiment was carried out in Kasr Rashwan village at Tameya province, Fayoum Governorate, Egypt during season (2015) to study the effect of SiO 2 nano fertilizers foliar spray at a rates of (0, 15, 30, 60 and 120 mg LG 1 ) on growth parameters, yield and chemical composition of cucumber (Cucumis sativa) under (agricultural drainage water). All data were subjected to an analysis of variance (One-way ANOVA) for a split-plot design, after testing for the homogeneity of error variances. Statistically significant differences between means were compared at p<0.05. Results: The outcome data revealed an increase in plant height (cm), number of leaves/plant, fresh and dry weights of leaves/plant (g), number of fruits/plant, mean weight of fruit, fruit length and yield kg/plant total yield t haG 1 as compared with the untreated plants under agricultural drainage water. Data also, demonstrated that application a foliar spray of SiO 2 nanoparticle at rate of 60 mg LG 1 gave a significant increase LSD<0.05 for most of growth parameter as compared to other treatments (15, 30 and 120 mg LG 1 ). Conclusion: Accordingly, results indicated increase in nitrogen and phosphorus, content and uptake and decrease in Na content and uptake when adding SiO 2 nano fertilizer. This study has identified that Silicon dioxide nano fertilizer can have a positive effect on the growth of plant and yield of cucumber.

Oil spill cases in the river Nile have been reported in the recent decade. Orange peel is a major waste of the food processing industry in Egypt, one of the six largest orange peel producers of the world. The purpose of the current work was to evaluate the oil sorption capacity of dried raw orange peel waste (OP) and thermally modified (300 °C and 500 °C) orange peel waste (TMOP). The effect of oil type, sorption time, particle size and reusability on the oil uptake of raw dried orange peel was assessed. Results have indicated that the oil sorption capacity of OP ranged between 3 and 5 g/g at 25 °C, while its water uptake was found to be below 1 g/g, making the selectivity of OP to oil relatively higher than other bio-sorbents. Orange peel could not be used for more than 5 oil sorption cycles, since the oleophilic nature of the peel surface was lost during the regeneration process. Compared to OP, limited percent increase in oil sorption capacity (18–40%) was observed after the thermal modification of orange peel. However, the water uptake of the TMOP is significantly higher than OP. Based on the liquid retention model data fit; the TMOP had better oil retention characteristics than the dried orange peel. According to the results presented, dried orange peel waste is a potentially cheap efficient oleophilic oil spill sorbent that losses its inherent oil selectivity after carbonization.

Abstract Climate models are crucial for assessing climate variability and change. A reliable model for future climate should reasonably simulate the historical climate. Here, we assess the performance of CMIP6 models in reproducing statistical properties of observed annual maxima of daily precipitation. We go beyond the commonly used methods and assess CMIP6 simulations on three scales by performing: (a) univariate comparison based on L‐moments and relative difference measures; (b) bivariate comparison using Kernel densities of mean and L‐variation, and of L‐skewness and L‐kurtosis, and (c) comparison of the entire distribution function using the Generalized Extreme Value ( ) distribution coupled with a novel application of the Anderson‐Darling Goodness‐of‐fit test. The results reveal that the statistical shape properties (related to the frequency and magnitude of extremes) of CMIP6 simulations match well with the observational datasets. The simulated mean and variation differ among the models with 70% of simulations having a difference within 10% from the observations. Biases are observed in the bivariate investigation of mean and variation. Several models perform well with the HadGEM3‐GC31‐MM model performing well in all three scales when compared to the ground‐based Global Precipitation Climatology Centre data. Finally, the study highlights biases of CMIP6 models in simulating extreme precipitation in the Arctic, Tropics, arid and semi‐arid regions.

Ultra-high performance concrete (UHPC) is a special type of concrete with extraordinary potentials in terms of strength and durability performance. Its production and application implement the most up-to-date knowledge and technology of concrete manufacturing. Sophisticated structural designs in bridges and high-rise buildings, repair works and special structures like nuclear facilities are currently the main fields of applications of UHPC. This paper aimed to evaluate the behavior of ultra-high strength concrete beams. This paper also aimed to determine the effect of adding fibers and explore their effect upon the behavior and strength of the reinforced concrete beams. A total of twelve simple concrete beams with and without shear reinforcements were tested in flexure. The main variables taken into consideration in this research were the type of fibers and the percentage of longitudinal reinforcement as well as the existence or absence of the web reinforcement. Two types of fibers were used including steel and polypropylene fibers. The behavior of the tested beams was investigated with special attention to the deflection under different stages of loading, initial cracking, cracking pattern, and ultimate load. Increased number of cracks was observed at the end of loading due to the use of fibers, which led to the reduced width of cracks. This led to increased stiffness and higher values of maximum loads.

Soil salinity is a serious problem facing many countries globally, especially those with semi-arid and arid climates. Soil salinity can have negative influences on soil microbial activity as well as many chemical and physical soil processes, all of which are crucial for soil health, fertility, and productivity. Soil salinity can negatively affect physiological, biochemical, and genetic attributes of cultivated plants as well. Plants have a wide variety of responses to salinity stress and are classified as sensitive (e.g., carrot and strawberry), moderately sensitive (grapevine), moderately tolerant (wheat) and tolerant (barley and date palm) to soil salinity depending on the salt content required to cause crop production problems. Salinity mitigation represents a critical global agricultural issue. This review highlights the properties and classification of salt-affected soils, plant damage from osmotic stress due to soil salinity, possible approaches for soil salinity mitigation (i.e., applied nutrients, microbial inoculations, organic amendments, physio-chemical approaches, biological approaches, and nano-management), and research gaps that are important for the future of food security. The strong relationship between soil salinity and different soil subdisciplines (mainly, soil biogeochemistry, soil microbiology, soil fertility and plant nutrition) are also discussed.

One of the most vital environmental factors that restricts plant production in arid and semi-arid environments is the lack of fresh water and drought stress. Common bean (Phaseolus vulgaris L.) productivity is severely limited by abiotic stress, especially climate-related constraints. Therefore, a field experiment in split-plot design was carried out to examine the potential function of ascorbic acid (AsA) in mitigating the adverse effects of water stress on common bean. The experiment included two irrigation regimes (100% or 50% of crop evapotranspiration) and three AsA doses (0, 200, or 400 mg L−1 AsA). The results revealed that water stress reduced common bean photosynthetic pigments (chlorophyll and carotenoids), carbonic anhydrase activity, antioxidant activities (2,2-diphenyl-1-picrylhydrazyl free radical activity scavenging activity and 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) radical cation assay), growth and seed yield, while increased enzymatic antioxidants (peroxidase), secondary metabolites (phenolic, flavonoids, and tannins), malondialdehyde (MDA), and crop water productivity. In contrast, the AsA foliar spray enhanced all studied traits and the enhancement was gradual with the increasing AsA dose. The linear regression model predicted that when the AsA dose increase by 1.0 mg L−1, the seed yield is expected to increase by 0.06 g m−2. Enhanced water stress tolerance through adequate ascorbic acid application is a promising strategy to increase the tolerance and productivity of common bean under water stress. Moreover, the response of common bean to water deficit appears to be dependent on AsA dose.

This study presents an evaluation of Egyptian diatomite as a low cost adsorbent for the removal of heavy metal under different conditions (pH, weight of diatomite and contact time). The adsorption of heavy metals was investigated under various pH values ranged from 2 to 8 at 25 °C. The obtained results indicate that at low pH (2–4), the removal efficiency of diatomite for heavy metal increased slightly as the pH, adsorbent dose and contact time increased, while at pH > 4, the percentage of metal ions adsorbed decreased with increasing pH due to precipitation of heavy metals. At pH equal 4, with using 2 g L−1 of diatomite and 75 min as contact time, the maximum adsorption capacity of diatomite was obtained. The high adsorption capacity of diatomite makes it a suitable low cost material for the removal of different heavy metals from aqueous solutions.

A rainfall-runoff model based on an artificial neural network (ANN) is presented for the Blue Nile catchment. The best geometry of the ANN rainfall-runoff model in terms of number of hidden layers and nodes is identified through a sensitivity analysis. The Blue Nile catchment (about 300 000 km2) in the Nile basin is selected here as a case study. The catchment is classified into seven subcatchments, and the mean areal precipitation over those subcatchments is computed as a main input to the ANN model. The available daily data (1992–99) are divided into two sets for model calibration (1992–96) and for validation (1997–99). The results of the ANN model are compared with one of physical distributed rainfall-runoff models that apply hydraulic and hydrologic fundamental equations in a grid base. The results over the case study area and the comparative analysis with the physically based distributed model show that the ANN technique has great potential in simulating the rainfall-runoff process adequately. Because the available record used in the calibration of the ANN model is too short, the ANN model is biased compared with the distributed model, especially for high flows. Copyright © 2005 John Wiley & Sons, Ltd.

BACKGROUND: Investigating the current level and trends of access and identifying the underlying challenges to sanitation system development will be useful in determining directions developing countries are heading as they plan to promote sustainable development goals (post 2015 agenda). This research investigates the status and trends of access to improved sanitation coverage (ISC) in relation to the MDG target in Ethiopia with the aim of identifying prevailing constraints and suggesting the way forward in the post-MDG era. METHOD: We examined data from a nationwide inventory conducted in accordance with the sanitation ladder at the national level and from a household survey in randomly selected urban slums in Addis Ababa. The inventory data were analyzed and interpreted using the conceptual model of the sanitation ladder. We used administrative reports and survey results to plot the time trend of the ISC. RESULTS: The data from the nationwide inventory of sanitation facilities, which are presented along the sanitation ladder reveal that more than half of the Ethiopian population (52.1%) still used unimproved sanitation facilities in 2014. The majority (35.6%) practiced open defecation, implying that the country is far from the MDG target for access to improved sanitation (56%). Most people in urban slums (88.6%) used unimproved sanitation facilities, indicating that the urban poor did not receive adequate sanitation services. Trend analysis shows that access to ISC has increased, but Central Statistical Authority (CSA) data reveal a decline. This discrepancy is due to differences in data collection methods and tools. Dry pit latrines are the most widely used toilet facilities in Ethiopia, accounting for about 97.5% of the ISC. CONCLUSION: The sanitation coverage is far from the MDG target and the majority of the population, mainly the urban poor, are living in a polluted environment, exposed to water and sanitation-related diseases. The sanitation coverage estimates might be even lower if proper utilization, regular emptying, and fecal sludge management (FSM) of dry pit latrines were considered as indicators. In order to enhance sanitation services for all in the post-MDG era, urgent action is required that will establish proper monitoring and evaluation systems that can measure real access to ISC.

Abstract. Serious environmental problems are emerging in the River Nile basin and its groundwater resources. Recent years have brought scientific evidence of climate change and development-induced environmental impacts globally as well as over Egypt. Some impacts are subtle, like decline of the Nile River water levels, others are dramatic like the salinization of all coastal land in the Nile Delta – the agricultural engine of Egypt. These consequences have become a striking reality causing a set of interconnected groundwater management problems. Massive population increase that overwhelmed the Nile Delta region has amplified the problem. Many researchers have studied these problems from different perspectives using different methodologies, following different objectives and, consequently, arrived at different findings. However, they all confirmed that significant groundwater salinization has affected the Nile Delta and this is likely to become worse rapidly in the future. This article presents, categorizes and critically analyses and synthesizes the most relevant research regarding climate change and development challenges in relation to groundwater resources in the Nile Delta. It is shown that there is a gap in studies that focus on sustainable groundwater resources development and environmentally sound protection as an integrated regional process in Nile Delta. Moreover, there is also a knowledge gap related to the deterioration of groundwater quality. The article recommends further research that covers the groundwater resources and salinization in the whole Nile Delta based on integrated three-dimensional groundwater modelling of the Nile delta aquifer.

Longitudinal dispersion in pipelines leads to changes in the characteristics of contaminants. It is critical to quantify these changes because the contaminants travel through water networks or through chemical reactors. The essential characteristics of longitudinal dispersion in pipes can be described by the longitudinal dispersion coefficient. This paper presents the application of evolutionary gene expression programming (GEP) to develop new empirical formulas for the prediction of longitudinal dispersion coefficients in pipe flow using 220 experimental case studies of the dispersion coefficient with a R range of 2,000–500,000 spanning transitional and turbulent pipe flow. Gene expression programming is used to develop empirical relations between the longitudinal dispersion coefficient and various control variables, including the Reynolds number, the average velocity, the pipe friction coefficient, and the pipe diameter. Four GEP models are developed, and the weight and importance of each control variable is presented. The prediction uncertainties of all of the developed GEP models are quantified and compared with those of existing models. Finally, a parametric analysis is performed for further verification of the developed GEP models. The results indicate that the proposed relations are simple and can effectively evaluate the longitudinal dispersion coefficients in pipe flow.