Water Surface Evaporation Research Articles

Water Quality Prediction of Water Sources Based on Meteorological Factors using the CA-NARX Approach

With the increasingly serious problem of surface water environmental safety, it is of great significance to study the changing trend of reservoir water quality, and it is necessary to establish a water quality prediction and early warning system for the management and maintenance of water resources. Aiming at the problem of water quality prediction in reservoirs, a CA-NARX algorithm is designed, which combines the improved dynamic clustering algorithm with the idea of machine learning and the forward dynamic regression neural network. The improved dynamic clustering algorithm is used to classify the eutrophication degree of waterbodies according to the total phosphorus and total nitrogen content. Considering four meteorological factors, air temperature, water temperature, water surface evaporation, and rainfall, synthetically for each water quality condition, the total phosphorus and total nitrogen in the waterbody are forecasted by an improved forward NARX dynamic regression neural network. Based on this, the CA-NARX prediction algorithm can realize short period water quality prediction. Compared with the traditional support vector regression machine model, improved GA-BP neural network, and exponential smoothing method, the CA-NARX model has the least prediction error.

Identifying surface water evaporation loss of inland river basin based on evaporation enrichment model

AbstractAccurately quantifying the evaporation loss of surface water is essential for regional water resources management, especially in arid and semi‐arid areas where water resources are already scarce. The long‐term monitoring of stable isotopes (δ18O and δ2H) in water can provide a sensitive indicator of water loss by evaporation. In this study, we obtained surface water samples of Shiyang River Basin from April to October between 2017 and 2019. The spatial and temporal characteristics of stable isotopes in surface water show the trend of enrichment in summer, depletion in spring, enrichment in deserts and depletion in mountains. The Local Evaporation Line (LEL) obtained by the regression of δ2H and δ18O in surface water has been defined by the lines: δ2H = 7.61δ18O + 14.58 for mountainous area, δ2H = 4.19δ18O − 17.85 for oasis area, δ2H = 4.08δ18O − 18.92 for desert area. The slope of LEL shows a gradual decrease from mountain to desert, indicating that the evaporation of surface water is gradually increasing. The evaporation loss of stable isotopes in surface water is 24.82% for mountainous area, 32.19% for oasis area, and 70.98% for desert area, respectively. Temperature and air humidity are the main meteorological factors affecting the evaporation loss, and the construction of reservoirs and farmland irrigation are the main man‐made factors affecting the evaporation loss.

Reliable Evapotranspiration Predictions with a Probabilistic Machine Learning Framework

Evapotranspiration is often expressed in terms of reference crop evapotranspiration (ETo), actual evapotranspiration (ETa), or surface water evaporation (Esw), and their reliable predictions are critical for groundwater, irrigation, and aquatic ecosystem management in semi-arid regions. We demonstrated that a newly developed probabilistic machine learning (ML) model, using a hybridized “boosting” framework, can simultaneously predict the daily ETo, Esw, & ETa from local hydroclimate data with high accuracy. The probabilistic approach exhibited great potential to overcome data uncertainties, in which 100% of the ETo, 89.9% of the Esw, and 93% of the ETa test data at three watersheds were within the models’ 95% prediction intervals. The modeling results revealed that the hybrid boosting framework can be used as a reliable computational tool to predict ETo while bypassing net solar radiation calculations, estimate Esw while overcoming uncertainties associated with pan evaporation & pan coefficients, and predict ETa while offsetting high capital & operational costs of EC towers. In addition, using the Shapley analysis built on a coalition game theory, we identified the order of importance and interactions between the hydroclimatic variables to enhance the models’ transparency and trustworthiness.

Hot Air and Microwave Combined Drying of Potato Monitored by Infrared Thermography

Hot air drying (HAD) at temperatures below the spontaneous evaporation temperature could be combined with microwave (MW) radiation as a thermal energy source in order to reduce the drying time. A photon flux in the microwave range interacts with dipolar molecules (water) through orientation and induction, producing electrical energy storage and thermal energy accumulation and generating an increase in the internal energy of food. The different mechanisms involved in water transport could change when the microwave penetration depth exceeds the sample characteristic dimension of mass transport. The aim of this paper is to determine the effect of MW in the combined HAD-MW drying of raw potato in order to obtain the real driving forces and mechanisms involved in the water transport, with the purpose of optimizing the MW power used. For this purpose, combined drying was carried out on potato samples (0, 4 and 6 W/g). The sample surface temperature was monitored by infrared thermography, and the sample mass was measured continuously through a precision balance. In parallel with continuous drying, another drying treatment was performed at different times (20, 40, 60, 90, 120, 180, 420 min) and conditions (0, 4 and 6 W/g) to analyze the dielectric properties, mass, moisture, volume and water activity. The results show that it is possible to monitor combined drying by infrared thermography, and it can be concluded that the convection heating is mostly transformed into surface water evaporation, with negligible thermal conduction from the surface, and microwave radiation is mostly transformed into an increase in the potato’s internal energy.

The Calibration of Evaporation Models against the Penman–Monteith Equation on Lake Most

Evaporation is one of the main components of the water cycle in nature. Our interest in free water surface evaporation is due to the needs of ongoing hydric recultivation of the former Ležáky–Most quarry, i.e., Lake Most, and also other planned hydric recultivations in the region. One of the key components of hydric reclamation planning is the securitization of long-term sustainability, which is based on the capability to keep the final water level at a stable level. In our work, we are interested in the evaporation estimation in the area of Lake Most (Czech Republic, Europe). This lake has been artificially created only a few years ago, and nowadays we are looking for a simple evaporation model, based on which we will be able to decide which measurement devices have to be installed at the location to provide more localized data to the model. In this paper, we calibrate state-of-the-art simplified evaporation models against the Penman–Monteith equation based on the Nash–Sutcliffe efficiency maximization. We discuss the suitability of this approach using real-world climate data from the weather station located one km from the area of interest.

Deep lake water balance by dual water isotopes in Yungui Plateau, southwest China

Stable isotopes of water (δ18O and δ2H) serve as a practical tool in the understanding of regional hydrological cycle, in particular, where the regional water cycle is stressed by both climate change and human activities. Lake water in southwest China is believed to play an important role in the local hydrology and possible modification of local climate. Water isotopes in lake systems are influenced by both the input water isotope and surface evaporation, such that they can be used as a natural tracer to evaluate these effects. Here we present a detailed water isotope balance study in a plateau lake – Fuxian Lake, the deepest and largest water body in Yungui Plateau, southwest China, with analogues of a steady state of water isotope equilibrium. The lake water isotopes are significantly enriched in heavy isotope due to evapoconcentration during the long residence time. We simulated the dual isotopes in the lake water using the Craig and Gordon model constrained by the observed water isotopes in lake water, river water, and atmospheric vapor. Results show consistent results for both δ18O and d-excess with values of −2.6‰ and −9.0‰ at the present relative humidity and E/I ratio. The test simulations also demonstrate how potential change in climate and/or lake water E/I ratio could impact lake water isotopes, and how the dual water isotope approach can unequivocally define the climatic and hydrological controls on lake water isotopes. These findings may be relevant for anticipating and detecting hydrological response to future climate change and water source management, e. g. inter - basin diversion projects. The results from this study highlight the potential of water isotopes in regional water cycle work, paleo climate reconstruction from lacustrine record, as well as human activity on water management.

Investigation of the Evaporation Rate of Water from Colloidal Unimolecular Polymer (CUP) Systems by Isothermal TGA

Studies of the evaporation of aqueous nanoparticle solutions have been limited due to lack of homogeneity of the solution, difficulties in obtaining reproducible samples and stability of substrates, as well as the effect of other volatile components or contaminants such as surfactants. Colloidal unimolecular polymer (CUP) is a spheroidal nanoparticle with charged hydrophilic groups on the surface, and the particle size ranges from 3 to 9 nm. The large amount of surface water on the CUP surface provides the opportunity to evaluate the evaporation of surface water, which may contribute to the investigation the factors that affect the evaporation rate in solutions of ultra-small particles, like protein, micelle, colloidal, etc. Six CUP systems were evaluated by thermogravimetric analysis (TGA) with respect to time and solids content. The evaporation rate of water was initially enhanced due to the deformation of the air-water interface at low to moderate concentration due to particle charge repulsive forces. At higher concentrations, above 20%, surface charge condensation and increasing viscosity began to dominate. At higher concentration where the CUP reached the gel point the rate of diffusion controlled the evaporation. The final drying point was the loss of three waters of hydration for each carboxylate on the CUP surface.

Experimental Analysis of Water Evaporation Inhibition of Plain Reservoirs in Inland Arid Area with Light Floating Balls and Floating Plates in Xinjiang, China

To reduce the ineffective evaporation of plain reservoirs in inland arid areas and improve the effective utilization of reservoirs, this work uses floating plates and floating balls as the main covering materials to reduce water surface evaporation. This paper investigates the motion characteristics of two covering materials with different structures under wind and waves through laboratory and field experiments. It analyzes the relation of evaporation inhibition rate of the floating plates and its area and thickness, and adopts the method of adding a counterweight to solve the problem of irregular rotation and easily rolling of the floating balls (the floating ball that serves as the added counterweight is called a tumbler floating ball). Then, it discusses the influence of diameter, counterweight, density, and type of the floating ball on evaporation inhibition rate by using the orthogonal design method and establishes a calculation equation of the water surface evaporation inhibition rate, which is applicable to the experiment area. Results show that: (1) the evaporation inhibition rate of the floating plates is positively correlated with the surface area and thickness, and (2) the influence degree of the four factors on the evaporation rate of the floating balls is diameter > counterweight > density > type of floating balls.

Climate change and predicting future temperature in Iraq using CanESM2 and HadCM3 modeling

Climate change and global warming have become a major environmental threat, especially for dry countries. Identifying and assessing future climate change are, therefore, paramount for suitable environmental planning to adapt to and reduce their effects. In this study, changes in the maximum and minimum temperatures in southwest Iraq during the period 2020–2099 were generated using two general circulation models (GCMs), CanESM2 and HadCM3, based on two special report emission scenarios (SRES), A2 and B2, and three representative concentration pathway (RCP) scenarios (RCP2.6, RCP4.5, and RCP8.5). Seven meteorological stations representing the study area were selected for model calibration and validation in the statistical downscaling model (SDSM) based on the observed period 1979–2018. The statistical indexes showed a good agreement between the downscaling and observed temperature data for seven meteorological stations in Iraq, where determination coefficient R2 ranged from 0.861 to 0.918 and 0.855 to 0.896 for maximum and minimum temperature, respectively. For the major changes, the results exhibited an increase in mean annual maximum temperature of between 0.48 and 2.5 ℃ (RCP8.5) over the stations by the end of the twenty-first century, while the minimum temperature is expected to rise by 0.22 ℃ (RCP2.6) and 1.76 ℃ (RCP8.5). This increase will affect water resources, because increased surface water evaporation causes water scarcity. HadCM3 shows greater maximum temperature changes than CanESM2 across Iraq.

Prediction model of ecological environmental water demand based on big data analysis

The existing prediction model of eco-environmental water demand has the problem of large prediction error. In order to solve the above problems, the prediction model of eco-environmental water demand is constructed based on big data analysis. In order to reduce the prediction error of the ecological environment water demand prediction model, the framework of the ecological environment water demand prediction model is built. On this basis, the principal component analysis method is used to select the auxiliary variables of the model. Based on the selected auxiliary variables, the minimum monthly average flow method is used to analyze the basic water demand of the ecological environment, the leakage water demand and the water surface evaporation ecological environment water demand, so as to analyze based on the results, the water demand of ecological environment is predicted by big data analysis technology, and the prediction of water demand of ecological environment is realized. The experimental results show that compared with the existing ecological environment water demand prediction model, the prediction error of the model is within 19.3, which fully shows that the constructed ecological environment water demand prediction model has better prediction effect and can provide a certain reference value for the actual use of water resources. • The framework of water demand prediction model reduces the prediction error. • Using the 3 σ rule to eliminate the abnormal data. • The minimum monthly average flow method is used to obtain the basic water demand.

Numerical Simulation Analysis of the Impact of Urbanization on an Extreme Precipitation Event over Beijing–Tianjin–Hebei, China

In this study, an extreme rainstorm that occurred in the Beijing–Tianjin–Hebei (BTH) region in China on 19–20 July 2016 is simulated and analyzed using the Weather Research and Forecasting model, coupled with a multilayer urban canopy scheme, to reveal the impact of urbanization on the extreme precipitation process in the region. The results show that the urban heat island effect (that is, surface warming and an increased near-ground sensible heat flux, which leads to increased vertical motion and atmospheric instability layer strengthening) plays a dominant role in the urban modification of rainfall during the early stages of urbanization, resulting in an increase of 6–10 mm in average hourly precipitation in urban and downwind areas. With the further development of urbanization in the BTH region, particularly in the big cities of Beijing and Tianjin, the large-scale expansion of the urban surface reduces the surface moisture, the evaporation of surface water from the ground, and the height of the atmospheric boundary layer, leading to an urban dry island effect brought about by the lack of near-surface water vapor, which inhibits an increase in precipitation. The positive effect of the urban heat island on precipitation was offset by the urban dry island effect, so the increase in precipitation in the urban areas was not obvious, but an increased range of 8–10 mm was noted. The existence of large cities changes the position of the strong upward movement of air, and convective upward movement is more likely to occur between the suburbs. With the further expansion of the underlying surface of the adjacent cities of Beijing and Tianjin, the upward movement between the two cities coincides, leading to an obvious increase in precipitation between the two cities.

Isotope Composition of Precipitation, Groundwater, and Surface and Lake Waters from the Plitvice Lakes, Croatia

The application of tritium, 2H, and 18O in the characterization of the precipitation, groundwater, and surface and lake water of the Plitvice Lakes (PL), Croatia, over the 1979–2019 period is presented. An increase in the mean annual air temperature of 0.06 °C/year and in the annual precipitation amount of 10 mm/year is observed. The good correlation of the tritium activity concentration in the PL and Zagreb precipitation implies that the tritium data for Zagreb are applicable for the study of the PL area. The best local meteoric water line at PL was obtained by the reduced major axis regression (RMA) and precipitation-weighted ordinary least squares regression (PWLSR) approaches: δ2HPWLSR = (7.97 ± 0.12) δ18O + (13.8 ± 1.3). The higher deuterium excess at PL (14.0 ± 2.2 ‰) than that at Zagreb reflects the higher altitude and influence of the Mediterranean precipitation. The δ2H in precipitation ranges from −132.4‰ to −22.3‰ and δ18O from −18.3 ‰ to −4.1‰. The much narrower ranges in the groundwater (<1‰ in δ18O, <10‰ in δ2H) indicate the good mixing of waters in aquifers and short mean residence times. The higher average δ2H in all three karst springs observed after 2003 can be attributed to the increase in the mean air temperature. The mean δ2H and δ18O values in the surface and lake water increase downstream due to the evaporation of surface waters. There is no significant difference between the surface water line and the lake water line (2011–2014). The stable isotope composition of the surface and lake waters reacts to extreme hydrological conditions.

Soil structuring using interpolyelectrolyte complexes of water‐soluble polysaccharides

Soil degradation is an important problem on a global scale. Suitable materials for its solution are interpolyelectrolyte complexes (IPEC) of biodegradable polymers. IPEC based on the oppositely charged pairs of biodegradable polymers—chitosan and sodium alginate (Ch‐SA), chitosan and sodium carboxymethylcellulose (Ch‐SC), and chitosan‐gellan gum (Ch‐GG) were prepared and studied using different physicochemical techniques (FTIR‐spectroscopy, dynamic light scattering, conductometric and turbidimetric titration, and rheoviscometric measurements). Thin films of IPECs were prepared by pouring polymer solutions on a flat surface and subsequent evaporation of water. These films were tested using mechanical analysis. Young modulus of IPEC films increases in the following order: Ch‐SC < Ch‐GG < Ch‐SA. Urban soil samples were sequentially treated with Ch solution and negatively charged polymer solution (SC, SA, GG). This technique of soil treatment leads to formation of IPEC within the soil surface layer. The soil structures and also soil treated with pure water and individual polymer solutions were also tested using mechanical analysis. It was found that the most durable structures are formed by IPEC based on Ch and SC. All the applied systems can be arranged in the following sequence in ascending order of the Young's modulus: GG < Ch < SA < Water < SC < Ch‐GG < Ch‐SA < Сh‐SC. The IPEC based on biodegradable and biocompatible polymers of polysaccharide nature can be successfully used for soil structuring. These polymers significantly increase the mechanical strength of the soil without harmful effects to the environment. Among the studied systems, the Ch‐SC system has the greatest structuring ability. These soil structuring agents can be applied for improving of the quality of urban and agricultural soils.

Flexible Pt3Ni-S-Deposited Teflon Membrane with High Surface Mechanical Properties for Efficient Solar-Driven Strong Acidic/Alkaline Water Evaporation.

Solar-driven water evaporation provides a promising solution to the energy crisis and environmental issues. Capitalizing on the high photothermal conversion efficiency and excellent resistance to strong acids or strong alkalis of Pt3Ni-S nanowires, we strategically design and prepare a flexible Pt3Ni-S-deposited Teflon (PTFE) membrane for achieving efficient strong acid/alkaline water evaporation under simulated sunlight irradiation (1 sun). By comparing the surface morphology, mechanical properties, and water evaporation performance of the as-prepared three different membranes, we have screened out a high-performance photothermal membrane that has good hydrophobicity (water contact angle = 106°), strong mechanical properties, high light-to-heat conversion efficiency (η = 80%), and excellent durability (10 cycles in a range of pH = 1.2-12). In particular, we explore the mechanism of high surface mechanical properties of the as-prepared membrane using density functional theory. The results demonstrate that the related mechanism can be ascribed to two main reasons: (1) hydrogen bonds can be formed between the 2-pyrrolidone ring and PTFE-3 and (2) the O atom in PTFE-3 carries more negative charge (-0.19 |e|) than PTFE-1 (-0.16 |e|) and PTFE-2 (-0.15 |e|). Our work highlights the great potentials of a Pt3Ni-S-deposited PTFE membrane as a device for implementing solar energy-driven evaporation of industrial wastewater with strong acidity or alkalinity and provides a new strategy for improving the surface mechanical properties of a photothermal membrane.

ESTIMATION OF WATER BALANCE UNDER THE CONDITIONS OF CROPS GROWING ON DRY PEAT SOILS OF POLISSІA ZONE

The paper presents the data concerning the researches which point out to the fact that the soil water flow plays an important role in the natural conditions biological complex as well as in the amelioration practice. The intensity of the soil water-intake process has been characterized by its variability and depends on the porousness, mechanical, mineral, chemical composition as well as on itscultivation, soil spaces, cracks, moles, roots and other openings. The water balance of meliorated soils includes some components such as the precipitation, surface and subsurface waters, which comes from he nearest headers, infiltrated rivers and storages lakes waters as well as from condensed waters, transpiration, soil and water surface evaporation in particular. The research of the matter needs the detail scientific substantiation under the conditions of different crops growing on dry soils of Polissya zone. The water balance of cropsgrowing on dry peat soils during the vegetation period for the layer of 0-50 cm has been investigated. The calculations showed that the process of water supply optimization on dry peat soils had an essential effect on its yielding level, herewith the crops efficiency under the regulated and controlled soils water levels increased greatly. Natural LSW comprise to special years as well as to theperiods of plant vegetation. In this case, the methods of moisture intensive management and modelling usage, can supply plant biological necessity under the efficient and qualitative yielding formation. The optimal moisture under the layer of 0-50 cm on dry peat soils during the period of yield forming for the perennial grasses and vetch-oat mixtures made up 77-89%. It has become possible to achieve the highest efficiency of crops green mass due to a givenmoisture parameters.

Isolation of Methylococcus Strain Resistant to Abnormal Climate Change to Reduce Methane Emissions from the Iranian Salt Lake

An increase in the atmospheric concentration of methane greenhouse gas results in an increase in global warming, surface water evaporation, and amount of the solutes in relevant areas besides, it also causes climate change. In these situations, methanotrophs that are resistant to climate change and deserted conditions could be applied. Methylococcus, as one of the most extensively studied methanotrophs is highly resistant to salinity, a strain of which was isolated in this study from Hoz-e Soltan Salt Lake in Iran as an example influenced by climate change. Isolated strain was identified. To determine the ability of the bacteria for decrease of methane gas, the culture medium was analyzed by gas chromatography. Results showed that isolated strain is able to grow in salt proportion of 3.3% and acidic pH of 3.5 in vitro, reducing more than 75% of total methane gas within 10 days. In addition to nitrogen fixation ability of the strain, positive results obtained regarding drought tolerance and heat shock in this study confirmed that Methylococcus strains may be able to withstand environmental conditions of foreseeable future. Thus, to prevent methane emission in regions such as Hoz-e Soltan Salt Lake in Iran, more compatible methanotroph strains need to be identified and used.

Effects of sand‐mulch thickness on soil evaporation during the freeze–thaw period

AbstractControl of evaporation from seasonally frozen soil is an important method for alleviating water shortages in arid and semi‐arid areas. To investigate the inhibition of soil evaporation by sand and the major factors that influence soil evaporation, a series of field experiments with five sand‐mulch thicknesses (0 cm, bare soil [BS], 1 cm [T1], 2 cm [T2], 3 cm [T3] and 4 cm [T4], with an average diameter of 1 mm) were conducted during the freeze–thaw period in Northern China. Soil evaporation characteristics in the three freeze–thaw stages were revealed and the major factors influencing soil evaporation were analysed using grey correlation analysis. The results showed that the cumulative soil evaporation decreased with increasing sand‐mulch thickness during the freeze–thaw period, and only small differences in soil evaporation were observed between the T3 and T4 treatments. The reduction in soil evaporation under different sand‐mulch thicknesses was 19.2–62.6% in the unstable freezing stage (P1), 2.0–28.3% in the stable freezing stage (P2) and 4.8–20.4% in the thawing stage (P3). In P1, solar radiation was a major factor influencing soil evaporation in all treatments and vapour pressure was a major factor in the sand‐mulch treatments, and the influence of relative humidity on soil evaporation decreased in the T4 treatment. During the coldest P2, solar radiation was lowest so that relative humidity and wind speed became the more dominant influence factors on soil evaporation in all treatments, and surface soil water content was a major factor in the sand‐mulch treatments. In P3, average air temperature and solar radiation were major factor influencing soil evaporation in all treatments and vapour pressure was a major factor in the BS and T1 treatments, whereas water surface evaporation was the major factor in the T2, T3 and T4 treatments. The results suggest that the addition of sand mulch in agricultural fields may be a beneficial practice to reduce water stress in arid and semi‐arid areas.

Modeling of Water Fluxes and Budget in Nam Co Basin during 1979–2013

AbstractIn this study, we established a hydrologic modeling framework over the Nam Co Lake basin by linking a glacier-melt scheme with a physically based, distributed land surface hydrologic model, and a heat-balance model was used for water surface evaporation. Hydrologic processes including evapotranspiration from land regions, runoff from both glacierized and nonglacierized areas, and lake surface evaporation were continuously modeled for 1979–2013, and then lake level changes were reconstructed. Rainfall runoff, snowmelt runoff, and glacier runoff contributed 59%, 28%, and 13% of total runoff, respectively. For the high-altitude region, runoff was mostly generated from glaciers. The lake had a positive water budget in most of the years with an average lake level depth of 128.8 mm, resulting in a total rise of approximately 4.5 m. Precipitation and precipitation-induced runoff were the main water supplies and played a dominant role in lake growth. Although the glacier runoff only contributed 13% of the total runoff, it played an important role in controlling the water level. The rising temperature led to increasing evaporation in two ways: one was providing an energy source for evaporation, and the second was extending the ice-free period. This mitigated the recent expansion of the lake, but on the other hand, it led to increasing glacier runoff into the lake. Hence, the rising temperature had two diametrically opposed effects on lake water balance.

A novel nonlinear Arps decline model with salp swarm algorithm for predicting pan evaporation in the arid and semi-arid regions of China

Accurate prediction of water surface evaporation (Ep) is important in the fields of both hydrology and irrigation engineering. This study evaluated the potential ability of a new hybrid model based on the salp swarm algorithm (SSA) and the kernel-based nonlinear Arps decline (KNEA) in predicting Ep. Two other common machine learning models, including the M5 model tree (M5) and the multivariate adaptive regression splines (MARS), were also applied in this study for comparison. All models were developed using daily records between 2000 and 2015 from 12 meteorological stations in the arid and semi-arid regions of northwest China. These daily records, including the maximum and minimum temperatures, solar radiation, wind speed and relative humidity, were randomly divided into two parts, with 70% of which used for model calibration and the others applied for validation. Four different parameter input combinations were equipped to explore the possibility of improving model accuracy. Two data application scenarios and five statistical indicators including the root-mean-square-error (RMSE), mean absolute error (MAE), scatter index (SI), d-index and determination coefficient (R2) were used for model evaluation. In the scenario of using local data as inputs for model calibration and validation, the impacts of wind speed and relative humidity on Ep were both greater than that of solar radiation, and SSA-KNEA was consistently superior to MARS or M5 across all the input combinations. In the scenario of using cross-station data, in which models using the best input combination were developed by local data of each station but validated by data from each of the remaining 11 stations, SSA-KNEA models performed better than MARS or M5 models on average. In addition, the SSA-KNEA model established by data from Station 51777 was the most suitable generalized model in this research area. Overall, our findings suggested that the new hybrid algorithm (i.e., SSA-KNEA) has high potential for Ep estimation in the arid and semi-arid regions of China, with local or cross-station data.

Alleviating Water Scarcity in the Central Rift Valley Lakes through an Inter-Basin Water Transfer, Ethiopia

Demand for fresh water, as one of the major natural resources, is increasing rapidly with increasing development and environmental degradation. The continued abstraction of water from Lake Ziway and its main feeder rivers Meki and Katar for irrigation indicates that the water demand may soon exceed the supply. To illustrate disparities in spatial distribution of water resources, the Upper Awash sub-basin, which shares a water-divide with the CRVL sub-basin, has large flow volumes particularly in the rainy season and suffers with seasonal flooding. The rationale behind regaining the water in CRVL relies on this non-uniform spatial distribution of fresh water, calling for a balance between water surplus and deficit regions. For this reason, Inter Basin Water Transfer (IBWT) is suggested as a viable option to augment utilizable water resources of the Upper Awash sub-basin to reduce the significant pressure on the water supply of the rapidly developing urban and irrigation areas in the CRVL sub-basin. A water evaluation and planning (WEAP) model was used to quantify the amount of surplus water in the donor basin, when examining the hydrological dynamics of the basins. Furthermore, optimal flow diversion scenarios were generated by maintaining two baseline scenario constraints. The estimated surplus water in the rainy season is expected to contribute 18 million cubic meters (mcm), 88 mcm and 192 mcm in months June, July and August respectively under average conditions. The optimal amount of diverted water could potentially stabilize the environmental degradation of Lake Ziway and Lake Abijata by compensating for development-driven abstraction and surface water evaporation respectively.