Baseflow is the primary source of water for irrigation and other water needs during prolonged dry periods; accurate and rapid estimation of baseflow is therefore crucial for water resource allocation. This research aims to estimate baseflow contribution during dry periods in three small watersheds in East Java: Surabaya-Perning (114 km2), Lamong-Simoanggrok (235 km2), and Bangsal-Kedunguneng (26 km2). Six recursive digital filters (RDFs) algorithms are explored using a procedure consisting of calibration, validation, evaluation and interpretation. In this study, the period of July to September is considered as the peak of the dry season. Moreover, data for the period 1996 to 2005 is used to calibrate the algorithms. By yearly averaging, values are obtained for the parameters and then used to test performance during the validation period from 2006 to 2015. Statistical analysis, flow duration curves and hydrographs are used to evaluate and compare the performance of each algorithm. The results show that all the filters explored can be applied to estimate baseflow in the region. However, the Lyne–Hollick (with RMSE = 0.022, 0.125, 0.010 and R2 = 0.951, 0.968, 0.712) and exponentially weighted moving average or EWMA (with RMSE = 0.022, 0.124, 0.009 and R2 = 0.957, 0.968, 0.891) for the three sub-watersheds versions give the best performance.

Water and wind erosion are the most powerful factors in the decrease of soil fertility and a threat to food security. The study was conducted on the steppe zone in Ukraine (total area of 167.4 thous. km2), including agricultural land (131.6 thous. km2). At the first stage, the modeling of spatial differentiation of water and wind erosion manifestations was carried out to calculate losses of soil (Mg·ha–1) and to determine their degradation. At the second stage, soil-climatic bonitet of zonal soils (points) is carried out to determine their natural fertility (Mg·ha–1). At the third stage, the spatial adjustment of the natural soil fertility to the negative effect of erosion was carried out. This made it possible to calculate crop losses and total financial losses due to water and wind erosion. The integrated spatial modeling showed that about 68.7% of arable land was constantly affected by the combined erosion, in particular the area of low eroded arable land (16.8%), and medium and highly eroded land (22.1%). Due to erodibility of soil, about 23.3% of agricultural land transferred from the category of high and medium quality to medium, low and very low quality, which is caused by the loss of soil fertility of up to 70%, crop losses of up to 1.93 Mg·ha–1 ha–1 and eduction of agricultural income up to 390 USD·ha–1. In the steppe region under the research, gross crop losses from erosion were up to 15.11 thous. Mg·ha–1 (3.05 mln USD). In order to protect soils, improve fertility and increase crop yields in the steppe zone in Ukraine, the following measures were suggested: adaptive and landscape erosion control design with elements of conservation farming in accordance with the spatial differentiation of soil quality and extent of water erosion deflation danger.

The purpose of this study is to develop mathematical models based on artificial intelligence: Models based on the support vectors regression (SVR) for drought forecast in the Ansegmir watershed (Upper Moulouya, Morocco). This study focuses on the prediction of the temporal aspect of the two drought indices (standardized precipitation index – SPI and standardized precipitation-evapotranspiration index – SPEI) using six hydro-climatic variables relating to the period 1979–2013. The model SVR3-SPI: RBF, ε = 0.004, C = 20 and γ = 1.7 for the index SPI, and the model SVR3-SPEI: RBF ε = 0.004, C = 40 and γ = 0.167 for the SPEI index are significantly better in comparison to other models SVR1, SVR2 and SVR4. The SVR model for the SPI index gave a correlation coefficient of R = 0.92, MSE = 0.17 and MAE = 0.329 for the learning phase and R = 0.90, MSE = 0.18 and MAE = 0.313 for the testing phase. As for the SPEI index, the overlay is slightly poorer only in the case of the SPI index between the observed values and the predicted ones by the SVR model. It shows a very small gap between the observed and predicted values. The correlation coefficients R = 0.88 for the learning, R = 0.86 for testing remain higher and corresponding to a quadratic error average MSE = 0.21 and MAE = 0.351 for the learning and MSE = 0.21 and MAE = 0.350 for the testing phase. The prediction of drought by SVR model remain useful and would be extremely important for drought risk management.

The article discusses the option for the application of the methodology for the solution of boundary value problems on the conformal mapping for the calculation of filtration process in the horizontal systematic drainage, provided that the drain is installed at a different depth. In particular, the case of methods combining fictitious areas and quasiconformal mappings for solving nonlinear boundary conditions problems for calculating filtration regimes in soils with free sections of boundaries (depression curves) and intervals of the “drainage” type. As an example, the authors designed a hydrodynamic flow grid, determined the values of the flows to the drain, established a section line and elicited other process characteristics. The algorithm for the numerical solution of model nonlinear boundary conditions problems of quasiconformal reflection in areas bounded by two equipotential lines and two flow lines, when for one of the sections, the boundary is an unknown (free) curve with fixed and free ends. The conducted numerical calculations prove that the problems and algorithms of their numerical solution, with a relatively small iterations number (k = 141) suggested in the paper, can be applied in the simulation of nonlinear filtration processes that arise in horizontal drainage systems. Total filtration flow obtained Q = 0.9 dm3·s–1; flow for drains Q1 = 0.55 dm3·s–1 and Q2 = 0.35 dm3·s–1 are quite consistent with practically determined values.

The accumulation of moisture from autumn and winter precipitation in poorly draining soil for plants in arid conditions during the initial stage of the vegetation period in the northern region of Kazakhstan was a severe production problem. Research methods included theoretical and experimental studies. In theoretical studies, the area of the treated surface by a chain harrow is determined. Then, the design of an improved harrow is proposed, including how the tooth chain tillage tools are positioned. Either as a “single action disc harrow” type with mounting four teeth on each chain link, or as a serial harrow with the tooth chain tillage tools located in a “diamond-shaped” double-action scheme with two teeth on each chain link. Experimental studies show that an improved harrow steadily performs the early spring harrowing process with a quality that meets normative requirements. In doing, so the working capacity is 4–5% higher than a serial harrow with a 4–5% lower fuel consumption. Furthermore, it is revealed that the early spring soil harrowing performed by tooth chain harrows allows the loss of productive moisture in the spring pre-sowing period by 1.8–1.9 times to be reduced compared to the untreated background.

This study attempts to find a fuzzy logic system for assessing the quality of water in water treatment plants (WTPs) providing water for irrigation purposes in the Basrah Governorate (South of Iraq). Each month, samples are taken in each of six major WTPs to measure electrical conductivity ( EC), and the content of sodium, magnesium and calcium. The calculated value which is the sodium adsorption ratio ( SAR) is plotted with EC on the Richard diagram. SAR and EC values are combined together in a fuzzy inference system (FIS) to find out a quality number called the fuzzy irrigation water quality index number ( FIWQI) which ranges from zero to one. The higher the value of the index, the better water quality. The Richard diagram, which helps to classify irrigation water, is used to adjust FIS components. Results show that the FIWQI for all WTPs changes depending on location and season. It ranges between 0.114–0.170, 0.120–0.190, 0.114–0.170, 0.114–0.202, 0.118–0.500 and 0.46–0.500 for Al-Bradhaia 1, Al-Jubaila 1, Shatt Al-Arab, Garmmah 1, Al-Rebat, and Old Shauaibah WTPs, respectively. The results indicate that WTPs effluent drawn from the Shatt Al-Arab River has poor water quality for irrigation purposes, except for an Old Shauaibah which receives water from another source called a sweet water canal. FIS results are compared with values obtained from the Richard diagram and 96% degree of compatibility between the two methods is attained. This indicates that FIS is an acceptable method for water quality classification.

The article discusses the spatial development of non-urban areas based on the use of local peat resources. Creating a methodology for the advanced spatial development of non-urban areas has peat resources based on multi- criteria optimisation of production and social infrastructures. The industrial and social infrastructure of the non-urban areas having reserves of peat, associated mineral, and industrial raw materials. Regularities, trends, and features of formation and functioning of the productive and social infrastructure of the natural and man-made complex in the development of peat reserves, associated mineral, and industrial raw materials. To achieve this goal, it is necessary to conduct interdisciplinary research and solve the following specific objectives: (1) the scientific justification of new technological processes and equipment for peat and mineral raw materials processing for obtaining new composite materials for multiple purposes; (2) the feature analysis of the use of local peat resources to provide the development of non-urban areas based on a set of scientific approaches; (3) the development of the methodology for project management of the natural and man-made complex to ensure multi-criteria optimisation of productive and social infrastructure. The example of the Khanty-Mansiysk Autonomous Okrug – Yugra development selected results of confronting the existing “big grand” and national challenges through the mechanisms of rational use of local peat resources non-urban areas are illustrated. The results indicated that by 2030 there would be a 3.8-fold increase in mineral extraction and a 5.9-fold increase in processing industries.

Over the past two decades, artificial neural networks (ANN) have exhibited a significant progress in predicting and modeling non-linear hydrological applications, such as the rainfall-runoff process which can provide useful contribution to water resources planning and management. This research aims to test the practicability of using ANNs with various input configurations to model the rainfall-runoff relationship in the Seybouse basin located in a semi-arid region in Algeria. Initially, the ANNs were developed for six sub-basins, and then for the complete watershed, considering four different input configurations. The 1st (ANN IP) considers only precipitation as an input variable for the daily flow simulation. The 2nd (ANN II) considers the 2nd variable in the model input with precipitation; it is one of the meteorological parameters (evapotranspiration, temperature, humidity, or wind speed). The third (ANN IIIP,T,HUM) considers a combination of temperature, humidity, and precipitation. The last (ANN VP,ET,T,HUM,Vw) consists in collating different meteorological parameters with precipitation as an input variable. ANN models are made for the whole basin with the same configurations as specified above. Better flow simulations were provided by (ANN IIP,T) and (ANN IIP,Vw) for the two stations of Medjez-Amar II and Bordj-Sabath, respectively. However, the (ANN VP,ET,T,HUM,Vw)’s application for the other stations and also for the entire basin reflects a strategy for the flow simulation and shows enhancement in the prediction accuracy over the other models studied. This has shown and confirmed that the more input variables, as more efficient the ANN model is.

The springs of the Taoura region flow from a syncline shaped structure. All resources in the region were mobilized as a result of increased demand. However, the development of anthropic activities and population growth in the area pose risk for groundwater. Analytical results obtained from a series of samplings in November 2017–April 2018, express the quality of water suitable for the irrigation of agricultural land. The highest values are recorded in April 2018 at 20.5 to 21.6°C and pH of 8.0 to 8.2. The study recorded high electrical conductivity from 1390 to 1495 μS·cm–1 and TDS from 1270 to 1500 mg·dm–3 in November 2017, which shows important mineralization that characterizes spring water. Physical parameters were measured in situ using a HORIBA multi-parameter probe. Chemical analyses were carried out using NFT 90-005 titration, and nitrogen parameters by DIN 38405-D92 spectrophotometry. Maximum levels of nitrates and phosphates were recorded at 228 and 18.4 mg·dm–3 respectively. The principal component analysis (PCA) showed a good correlation of the November 2017 period with mineralization parameters. Moreover, there is a strong correlation between the wet period and pollution factors. The two methods of analysis has allowed to distinguish three groups of geochemical water types: a bicarbonate calcium group typical for waters having transited in carbonate horizons. A second chloride calcium group shows basic exchange between water and clay levels, and the third chloride bicarbonate calcium group reveals an enrichment in calcium and chloride, which reflects water circulation with an exchange of the carbonated and evaporitic sedimentary rock matrix.

Biochar was prepared from corn ( Zea mays) stalks and impregnated with sulfuric acid. The biomass was impregnated for 24 h with a 50% solution of H2SO4 with impregnation ratios 1:2 (B 1:2) and 1:3 p/v (B 1:3); then, it was carbonized in a muffle furnace at 520°C for 30 min with a 10°C per min ramp. The adsorption capacity to remove anions (nitrate, sulfate, and phosphate) in an aqueous solution was evaluated by varying the temperature. The adsorption mechanism was studied by determining the thermodynamic parameters: Gibbs free energy (ΔGº), enthalpy (ΔHº) and entropy (ΔSº) standard. The biochars were characterized by Scanning Electron Microscopy-Energy Dispersive X-Ray Spectroscopy (SEM-EDS) analysis and were found to exhibit a heterogeneous surface and porous nature, with C, O, S, and Si. The experiments in the batch system showed the best performance of B 1: 2 in the removal of the three anions occurred at 303 K, while B 1: 3 had the best performance at 298 K. From the thermodynamic parameters, it was found that the removal processes are endothermic, their mechanism is by chemisorption. It is concluded that synthesized biochar is an excellent alternative to removing nutrient anions present in the solution.

This paper aims to analyse the flood discharge based on the Synthetic Unit Hydrograph (SUH), using the Soil Conservation Service method (SCS), the SUH of Nakayasu method, and the SUH of Gama I method. Modelling formed the basis of the research conducted on the Bengawan Solo River, Indonesia. The embankment construction on the Dengkeng–Pusur Section was designed as a method of flood control in 1988. The problem was that around its location are densely populated cities, industrial areas, and agricultural areas. In order to measure the risk of embankment failure and water structure planning in general, it is necessary to analyse the maximum flood discharge. There are several methods for analysing maximum flood discharge, so finding a suitable method is essential due to the lack of measuring tools to calculate flood discharge in some areas. The calculation is compared with the observation data at the Serenan AWLR station, which is in the Dengkeng–Pusur section. The observation rainfall data was covered a 20 year period (1999–2018). According to the method used, the analysis is based on series data on four rainfall stations, the watershed characteristics, and other parameters. Furthermore, the maximum flood discharge from the calculation is compared with the observational data at the Serenan station. The result shows that the best SUH is Gama I method compared to the observation maximum flood discharge in AWLR Serenan Station, with an 8.0% error. The other method, the SUH Nakayasu method with a 16.6% error, and the SUH SCS method with a 39.5% error.

Soil loss is a major problem for watersheds management in semi-arid environments. The objective of the present study is to analyze the annual and seasonal patterns of suspended loads and quantify the specific sediment yields in a semi-arid environment of the Mazafran Watershed in central Algeria. The obtained information of water discharge and suspended sediment load, recorded during 19 years, was confronted with precipitation data in order to establish the relationships between theforcing agents and erosive processes. The specific sediment yield was estimated by assessing rating curve data under two types of identified responses. The obtained results allowedconfirming the seasonality on suspended sediment transport in the studied basin, which accounts for 56% of the total suspended sediment load estimated in winter. The mean annual suspended sediment is estimated at 17.52 Mg·ha–1·y–1. The results highlighted that the type 2 event dominates the production of sediment in the study area in comparison with type 1 event. The analysis of the variability of rainfall erosivity index showed that there is a strong correlation between the annual precipitation and modified Fournier index ( MFI), and a weak correlation with the monthly precipitation concentration index ( PCI). Moreover, the spatial distribution of the modified Fournier index at the basin scale showed the highest precipitation aggressiveness in the Southern part of the study region for both type of events, whereas the precipitation aggressiveness low to moderate in the remaining part of the study region.

In this work, nickel adsorption onto low Jordanian zeolite dose is being investigated. Natural zeolite doses were stirred continuously with nickel solutions in batch reactors at 180 RPM for 24 hours, where the temperature was set to 20°C. The pH was initially 4.5 and reached 5.2 at equilibrium. The removal efficiency of nickel reaches maximum value when the initial nickel concentration is around 1 ppm and then tends to decrease when the initial nickel concentration increases above 1 ppm. The optimal nickel removal reaches 65% when the initial nickel concentration is 1 ppm and the zeolite dose is 26 mg·dm–3. This study investigates the behaviour of nickel removal and modelling isotherms below and above this critical peak point. At this level of zeolite dose, the adsorption does not follow either Freundlich or Langmuir isotherms, but rather, it follows Freundlich for the data plot just below the peak point with the highest coefficient of determination (R2) equals (0.98) when the zeolite dose is (26 mg·dm–3), whereas it follows Langmuir for the data plot just above the peak point with the highest coefficient of determination (R2) equals (0.99) when the zeolite dose is (10 mg·dm–3). These findings clarify the theory behind each isotherm and can be used to find new information for efficient treatment techniques.

The development of transport infrastructure strengthens the technogenic burden on the environment. Waste, thaw and rain waters from vehicle transport enterprises, such as car-washing installations, petrol stations, and car service stations may pollute ground and surface waters, and adjacent landscapes. The article presents quality parameters and suggests a number of measures permitting to minimize the harmful impact on the environment. The purpose is to improve the reagent treatment technology applicable to surface runoff from vehicle transport enterprises and the reuse of circulating waters by improving well-known methods with original technological procedures and chemical reagents. Research methods include the use of potentiometry, titrometry, and gravimetry. The investigation has shown the possibility to increase the efficiency of runoff treatment and removal of suspended particles and dissolved organic matter by 20–30%. This can be achieved by the application of a permanent magnetic field of 30–40 mT and the subsequent processing by the solution of aluminum chlorohydrate. Optimum parameters have been determined regarding magnetic field and processing conditions. It has been proven that the use of aluminum chlorohydrate in combination with polyhexamethyleneguanidine hydrochloride simplifies substantially the technological cycle. A better treatment can be achieved in comparison with the usual coagulant by 25%. Heavy metal ions are removed from water and the method includes microbiological disinfection and preservation of water in storage reservoirs. The improved technological scheme suggests the reagent treatment of storm and circulating waters for their repeated use.

In Algeria, modern agriculture was introduced in the Saharan region through the implementation of the law n° 83–18 of August 13, 1983, relating to access to agricultural land ownership (Fr. Accession à la Propriété Foncière Agricole (APFA) in French). This law was hugely successful and sparked a real enthusiasm for this type of activity, which resulted in an expansion of agricultural areas at the M’Zab level, similar to that observed in other Saharan regions. Over the past decades, the agricultural area has declined markedly (–0.4%), which was due to multiple causes, including ecological problems, such as urban discharges and the rise in the water level. So far, little research has been done to assess the agricultural situation and irrigation in this region. The objective of this work is to analyse and discuss the constraints and impacts of water and agricultural management on sustainability of the ecosystem in the Saharan environment. This work is based on extensive research, which has been carried out in the M’Zab region on the oasis system and its evolution. It was enriched with dozens of direct surveys, performed among farmers working in agricultural areas. The results show that agricultural development and the sustainability of farms in this region face several technical and social constraints, the most important of which are the workforce-related problems and water management. Several measures have been recommended to be taken not only to preserve the ecosystem but also to give significance to the large investments made by the public authorities.

Because of hydraulic jump, the scour downstream a stepped spillway is the most confusing issue that endangers the overall stability of the spillway. In this paper, thirty-six exploratory runs are described to explore the impact of utilizing submerged water jets fixed in the stilling basin of a stepped spillway on the downstream scour measurements under various flow conditions. A smooth apron where the water jets are disabled is incorporated to characterize the impact of adjustments studied. Trials are performed utilizing different upstream discharges, jets arrangements, and tailwater depths. The results are analyzed and graphically presented. The experimental data are contrasted to a scour formulae developed by other specialists. Outcomes indicated that by utilizing submerged floor water jets, the maximum scour depth is decreased between 14.3 and 36.0%. Additionally, the maximum scour length is reduced by 9.7 to 42.3%. Finally, involving regression analysis, simple formulas are developed to estimate different scour parameters.

Despite many studies on the hydrological responses to forest cover changes in micro and mesoscale watersheds, the hydrological responses to forest cover alterations and associated mechanisms through the large spatial scale of the river watershed have not been comprehensively perceived. This paper thus reviews a wide range of available scientific evidence concerning the impacts exerted by the forest removal on precipitation, water yield, stream flow, and flow regimes. It is concluded that there is no statistical correlation between forest cover and precipitation and water yield at the micro and mesoscale. In contrast, there is a relative correlation coefficient ( r = 0.77, p < 0.05) between forest cover and water yield at large scales (>1000 km2). These findings help our understanding of the hydrological response to forest disturbance at large and regional scale and provide a scientific perception to future watershed management in the context of human activities and natural hazards.

The production of biofuels using wastewater as a microalgae culture medium is a little explored technology, but with potential for success. In order to contribute to the knowledge of these technologies and their technical feasibility for microalgae growth, in this work the Chlorella sp. strain was cultivated in two types of effluents generated in an experimental farm located in eastern Colombia, before and after a biological treatment process. The consumption of the main nutrients that regulate growth and lipid production was evaluated, in order to extract, quantify, characterize and convert them into biodiesel. The results showed that Chlorella sp. growth and lipid production is more favourable in R2 medium of treated water than in R1 medium of raw water, mainly due to phosphorus limitation and higher N-NO3 concentration in R2 compared to R1. In the R2 medium culture, a percentage of 42.54% of long-chain fatty acids was found, which is necessary to obtain a high quality biodiesel. Finally, the best transesterification experiment allowed reaching a fatty acid methyl esters (FAME) percentage of 90.1 ± 2.7%. In general, the results demonstrated the potential viability of using the wastewater generated in the San Pablo farm to produce biomass with lipid content to obtain biodiesel, finding that where the concentration of nutrients, mainly nitrogen, has a great influence on the microalgal metabolism for lipid accumulation.