Irrigation
H. Mohammadzadeh; M. Bonyabadi; F. Jangjoo
Abstract
Introduction: Sulfate is one of the important groundwater pollutant sources in many parts of the world and it can enter into groundwater from various sources, such as lithology (dissolution of evaporative and pyrite oxidation), atmosphere (sea water spray), industrial (combustion of fossil fuels, sulfide- ...
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Introduction: Sulfate is one of the important groundwater pollutant sources in many parts of the world and it can enter into groundwater from various sources, such as lithology (dissolution of evaporative and pyrite oxidation), atmosphere (sea water spray), industrial (combustion of fossil fuels, sulfide- minerals production, and agricultural fertilizers), and etc. Identifying sources of soluble sulfate in water sources is important. The sulfate in groundwater can be investigated using isotope and geochemistry techniques. Using isotope (34S and 18O) and hydro geochemical techniques, it can be possible to find out: sulfate origins and the effective processes/reactions on sulfate concentrations and hydrogen sulfide gas (H2S) production. In this paper, for the first time, the sulfate source in groundwater of Sarpol Zahab and the parameters affecting sulfate concentration and its isotopic compositions (d34S and d18O) in groundwater were studied. Sarpol-e Zahab is located in the catchment area of Alvand river in the west of Kermanshah province, west of Iran. The formations of the region, based on age from old to new, include the Ilam, Gurpi, Amiran, Telezang, Pabdeh, Asmari, Gachsaran, Aghajari, Bakhtiari and Quaternary alluvium formations. Asmari formation and Quaternary alluvial sediments form the largest area of the region. Gachsaran formation contains evaporative materials which is reducing the quality of groundwater in the region. Ilam formation is effective in providing the organic matter required for the bacterial sulfate reduction process.
Materials and Methods: 13 water samples were taken from the water resources (wells, springs and river) of Sarpol-e Zahab region in two steps (December 2014 and September 2015). Measuring field parameters (T, pH, Eh, Ec, and TDS) and sampling of water resources were performed according to the instructions of Groundwater and Geothermal Research Center (GRC), Ferdowsi University of Mashhad. Field parameters were measured by VWR Handheld Multi parameter Research meter at the location of each water source. The concentration of cations and the anions were determined by the devices inductively coupled plasma elemental analyzer (ICP-EA) and ion chromatography (IC), respectively. Chemical and isotopic analyses of all water samples were performed in Ottawa university geochemistry laboratory and Waterloo university isotope laboratory, respectively. The measurement reference for isotopic sulfate and oxygen were VCDT and VSMOW, respectively, and the value isotopic are expressed as permil ((‰.
Results and Discussion: The sulfate concentrations in different water resources of the region varied from 5 to 950 mg L, however, it is very high in Gandab spring’ water, due to the association with hydrocarbons, and in Patagh Tunnel water, due to discharging of water from Gachsaran Formation (339.6 mg L and 950.1mg L, respectively). Chenarpiran spring has the lowest sulfate concentration because it is located in highlands and is discharged from Asmari formation with good water quality. The amount of d18O varied between 5.8 to 13.1 VCDT ‰ and the amount of d34S ranges from 9.5 to 31.8 VSMOW ‰. In Gandab spring’ water, due to sulfate reduction by microorganisms, in addition to the unpleasant smell of sulfide hydrogen (H2S), the d34S and d18O values were enriched than the isotopic composition of other water sources ( about 31.8 ‰ and 10.3 ‰, respectively). In other hand, the Gel va Darreh spring's water, due to the effect of upstream bath waste water (soap and detergent with a value of about 1 ‰ for d34S), indicated depleted isotope values.
Conclusion: The concentration and isotopic composition of sulfate in the water resources of the Sarpol-e Zahab region are affected by the geological, atmospheric, human and hydrocarbon materials. The impact of human and hydrocarbon factors on the concentration and isotopes of sulfate is local, however, the lithology effects are on all water resources of the region. Since, Gachsaran formation forms the alluvial aquifer bedrock of Ghaleshahin plain, the dissolution of gypsum has an effective role in the hydro chemical evolution of the alluvial aquifer of this plain. The lithology of the area is often limestone and evaporation. Due to the high solubility of these materials in water, they have been able to have a significant effect on sulfate isotopic in water sources. The amount of measured isotopic values indicated that the origin of evaporators and atmospheric sulfate is in water. The dissolution of the evaporation formation has reduced the water quality. The association of bedrock in the Gandab spring has led to have a reduction environment and the occurrence of sulfate reduction and production of hydrogen sulfide gas (H2S). The human activities (by making bath upstream) caused oxidizing conditions, isotopic depletion and contamination of the Glodarreh spring.
Irrigation
M. Komasi; A. Alizadefard
Abstract
Introduction: The occurrence of successive droughts, along with increasing water needs and lack of proper management of water resources has caused a water crisis that has various environmental and economic consequences. In addition to the drought, the change in the cropping pattern towards water crops ...
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Introduction: The occurrence of successive droughts, along with increasing water needs and lack of proper management of water resources has caused a water crisis that has various environmental and economic consequences. In addition to the drought, the change in the cropping pattern towards water crops has also made the water crisis the first critical phenomenon in recent years in the community, which has a direct impact on the agricultural sector as the largest consumer of water. Therefore, optimizing the cropping pattern is one of the most important factors in managing water resources and coping with water shortages. In this study, to determine the optimal cropping pattern of major crops in Silakhor plain in the next three years using two approaches using Linear Programming and Meta-Heuristic Algorithms. Materials and Methods: In the first step, in order to determine the optimal cropping pattern with the aim of maximizing farmers' incomes in the next three years and the limited water and land available, the amount of rainfall recharge is used as a criterion to determine the water exploitation interval and determine the minimum and maximum exploitation each year. In order to forecast rainfall, SARIMA time series models and Genetic Programming were used considering the data of the last 10 years in both seasonal and monthly modes, and according to RMSE and D.C. criteria, a better model was selected. Then, for each crop year, 100 exploitation scenarios were determined according to the amount of groundwater recharge caused by rainfall and the amount of exploitation in previous years. In the second step, Linear Programming was used to determine the optimal cropping pattern with the aim of maximizing farmers' incomes and limitations of exploitable water in each scenario and arable land. The price of each product is projected according to the average long-term inflation of the country, i.e., 20%, and the profit from the cultivation of each product was calculated as a proportion of the price of the product in each year by examining the previous years. Finally, the performance of three types of Static, Dynamic, and Classified Dynamics Penalty Functions into two algorithms, Differential Evolution and PSO was investigated to achieve the results obtained from Linear Programming. Static penalty functions use a constant value during the optimization process, whereas in dynamic penalty functions, the fines are modified during the process and depend on the number of generations. In the classified dynamics penalty, groups of violations are also determined, and the penalty of each response is determined according to the amount of violation of the restrictions and the generation number. Results and Discussion: The results show that with increasing groundwater exploitation, farmers' incomes also increase; However, in the exploitation of more than 223.5, 222.2, and 225.1 million cubic meters for the cropping years 2020-2021, 2021-2022, and 2022-2023, respectively, the limitation of the total arable land has prevented the increase of the area under cultivation, and by increasing exploitation, farmers' incomes remain stable. Also, in order to cultivate four crops of wheat, barley, rice, and corn with the current area under cultivation in Silakhor plain, 142 million cubic meters of water is harvested annually from underground sources. By optimizing the cropping pattern for the four crops studied, with the current water exploitation, the income of farmers in the region will increase by 18%. In general, the PSO algorithm answers this problem much faster. The average number of iterations of the PSO algorithm to solve each scenario in this problem is 38% of the number of iterations of the Differential Evolution algorithm. Overall, in solving this problem, the PSO algorithm has performed better in 84% of the scenarios. In penalty functions, the best performance in both algorithms belongs to the classified dynamics, dynamic, and static penalty functions, respectively. By changing the penalty function from static to classified dynamics penalty function, the number of iterations of the Differential Evolution algorithm to achieve the Linear Programming solution is reduced by an average of 11%; In contrast, the PSO algorithm did not react significantly to the change in the penalty function, and its repetitions decreased by an average of only 3%. Conclusion: The results show that the cropping pattern of the region is not optimal, and with the increase of water exploitation, it will move towards the cultivation of water products. Also, by optimizing the cultivation pattern of the region, farmers' incomes can be increased. Examination of Differential Evolution and PSO algorithms with three types of penalty functions also show that using the classified dynamics penalty function in the PSO algorithm can have good results.
Alieh Saadatpour; Amin Alizadeh; Ali Naghi Ziaei; azizallah izady
Abstract
Introduction: During the last decades, arid and semi-arid regions has faced a severe problem of depletion of groundwater resources due to the over-exploitation of the aquifer. Moreover, groundwater and surface water are not isolated components of the hydrologic system, but instead ...
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Introduction: During the last decades, arid and semi-arid regions has faced a severe problem of depletion of groundwater resources due to the over-exploitation of the aquifer. Moreover, groundwater and surface water are not isolated components of the hydrologic system, but instead interact in a variety of aspects in which development of one commonly affects the other. Additionally, the interaction is often complicated by agricultural activities including surface water diversion, groundwater pumping and irrigation. This study presents an integrated SWAT-MODFLOW model that couples land surface hydrology and groundwater hydrology to determine spatial groundwater percolation patterns considering allowable groundwater pumping rates for the Neishaboor watershed, Iran. Within the integrated model, the pumped groundwater is applied as irrigation to the cultivated fields within the SWAT model, with deep percolation from the soil profile bottom applied to the MODFLOW model as recharge. The model is tested against observed stream flow and water table elevation, with model output then used to assess and quantify spatial-temporal patterns of groundwater recharge to the aquifer.
Materials and Methods: The recently developed SWAT-MODFLOW modeling code simulates spatially-distributed hydrologic processes in the coupled land surface / aquifer system, with SWAT simulating land surface, soil zone, and stream flow routing processes and MODFLOW simulating groundwater flow and groundwater/surface water interaction processes. Modifications which is done to the modeling code includes: 1) Linking pumping from MODFLOW cells to SWAT HRUs for groundwater irrigation and 2) Imposing shallow water table percolation and lateral flow conditions for SWAT HRUs when the MODFLOW-simulated water table is within the soil profile of the HRU. The integrated SWAT-MODFLOW framework is tested in the Neishaboor watershed (9157 km2) for the 1998 to 2011 time period. Climate of the region is classified as semi-arid, with an average annual precipitation of 265 mm that varies considerably from one year to another. The mean annual temperatures changes from 13°C in the mountainous area to 13.8°C in the plain area and the annual potential evapotranspiration is about 2,335 mm. The main crops that are grown in the watershed is irrigated and rain fed wheat during fall and winter and corn silage during summer. Regarding previous studies, about 93.5% of the groundwater withdrawals in the Neishaboor watershed are consumed in agriculture, mostly for irrigation. Therefore, irrigation practices play a crucial role in the water resources balance in the study area. Within the integrated model, the pumped groundwater is applied as irrigation to the cultivated fields within the SWAT model, with deep percolation from the soil profile bottom applied to the MODFLOW model as recharge. The SWAT model was calibrated and tested in SWAT-CUP for the 2001-2009 and 2010-2011 periods, against stream flow and developed model was calibrated manually against groundwater level data.
Results and Discussion: Annual average recharge, calculated from the daily recharge values pass from SWAT to MODFLOW, demonstrating higher recharge rates in the alluvial fans and upland plain. Observed and simulated stream discharge in four hydrometric stations demonstrate good similarity results with the observed hydrograph. The NS values for monthly discharge rates are considered acceptable, however, the field-estimated stream flow estimates contain a high degree of uncertainty. Simulated cell-wise groundwater hydraulic head at the end of the simulation is compared with observation values with the highest water table elevation occurring in the north east and low water table elevation occurring in the outlet. Comparing observed and simulated average groundwater levels at the 48 monitoring wells, the deviation from the 45-degree line is less than 2.5 m for over 73% of the circles. The manual calibrated model can capture the main temporal trend. Overall, the model well captures the long-term characteristics of the regional groundwater level.
Conclusion: In this study, a new coupled model, referred to as SWAT-MODFLOW was used to model a dry and semi-arid region with a complicated irrigation system with groundwater pumping. A comprehensive model, will enable accurate simulations of stream flow and water table fluctuations in watersheds and aquifers respectably. In short, surface water infiltration is passed from SWAT to MODFLOW based on the contributing areas of the HRUs to the groundwater grid. Pumping agriculture water is then calculated and passed back to SWAT. The need for such a model is highlighted by the Neishaboor basin, where the agriculture is completely based on groundwater pumping. The case study in the Neishaboor basin demonstrated the applicability of the model for large, dry basins. The model will be used to determine best management practices for groundwater pumping in the region.
Banafsheh Sheikhipour; Saman Javadi; Mohammad ebrahim Banihabib
Abstract
Introduction: Most part of Iran is located in an arid and semi-arid region, thus in most parts of a region; groundwater is the only water resource also Population growth, limitation of surface water resources and excessive water withdrawal from the aquifers, caused a sharp drop in groundwater level in ...
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Introduction: Most part of Iran is located in an arid and semi-arid region, thus in most parts of a region; groundwater is the only water resource also Population growth, limitation of surface water resources and excessive water withdrawal from the aquifers, caused a sharp drop in groundwater level in many plains of Iran such as Shahrekord plain, So it is necessary to have suitable management plans to improve the aquifer and evaluate some indicators to see the effects of the methods. In this research, many management plans were assessed for the case study.
Materials and Methods: A groundwater numerical flow model (GMS 10.2) was established by using the monthly data including hydraulic heads, depletion volume of the wells, springs and qanats, precipitation values in Shahrekord aquifer. The model was prepared and calibrated for both status of steady (October 2010) and unsteady flow (November 2010-October 2012), and verified for the following year (November 2012- October 2013). The final values of hydraulic conductivity and specific discharge were obtained by trial and error and PEST method. The water level fluctuation was predicted for three years later (until October 2016) by applying management scenarios of 5% and 10% reduction in water withdrawal, underground dam and artificial recharge. After that, two indicators of Sustainability Index and modified Water Exploitation Index (WEI+) were calculated to determine the effect of the scenarios. The Sustainability Index indicates the consumption ratio of natural resources to water demand. The optimal value of this Index is 1 and it may also have negative values. Low values of this index mean high usage of natural resources. The Water Exploitation Index shows to which extent the total water demand puts pressure on water resources. This index has positive values and its optimal value is close to zero. These two indicators were used for surface water resources in the past studies so in this article they were redefined for underground water resources.
Results and Discussion: The result of groundwater modeling shows that the hydraulic conductivity from 1 to 25 m/day and specific yield from 0.01 to 0.08 are varied also the result of prediction shows that the underground water level would be decreased about 1.34 meter per year in the next 3 years when it hadn’t any management plans in this area but after 5% and 10% reduction water withdrawal scenarios Decreasing of water level were, respectively, 1.33 and 0.71 meter for each year also, considering that there were more wells in the center of the aquifer, water level in this area increased more than other areas, after 5% and 10% Reduction scenarios. According to the results of the artificial recharge and underground dam storage prediction, groundwater head increased in upstream of underground dam and the area near the artificial recharge. Considering the results it was found that the current condition of the aquifer is inappropriate and the amount of withdrawal from the aquifer is more than its capacity. The amount of Water Exploitation Index for business as usual scenario equal to 1.068 and for underground dam, artificial recharge, 5% and 10% reduction water withdrawal, were, respectively, equal to 1.068, 1.061, 1.045 and 0.969. Also the amount of Sustainability Index for business as usual scenario equal to 0.071 and for the other scenario were 0.068, 0.071 and 0.114. , respectively.
Conclusion: Considering the values of the indicators, 10% reduction water withdrawal scenario improved both indicators and selected as the best scenario. After that, 5% reduction water withdrawal was in the second place, then the artificial recharge scenario and underground dam scenarios, respectively, were in the third and fourth place. The scenario of underground dam had any positive effect on these two indicate. Regarding the calculated values of the indicators, it can be seen that although management scenarios have improved these two indicators, the amounts obtained are also significantly different from their optimal values. Several management scenarios can be used simultaneously to bring the calculated index values closer to their optimal values. Used two indicators of sustainability and modified water exploitation can be used exploitation for other management scenarios and assess the performance of them for the other aquifers.
Yavar Pourmohamad; Mohammad Mousavi baygi; Amin Alizadeh; Alinaghi Ziaei; Mohammad Bannayan
Abstract
Introductionin current situation when world is facing massive population, producing enough food and adequate income for people is a big challenge specifically for governors. This challenge gets even harder in recent decades, due to global population growth which was projected to increase to 7.8 billion ...
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Introductionin current situation when world is facing massive population, producing enough food and adequate income for people is a big challenge specifically for governors. This challenge gets even harder in recent decades, due to global population growth which was projected to increase to 7.8 billion in 2025. Agriculture as the only industry that has ability to produce food is consuming 90 percent of fresh water globally. Despite of increasing for food demand, appropriate agricultural land and fresh water resources are restricted. To solve this problem, one is to increase water productivity which can be obtain by irrigation. Iran is not only exempted from this situation but also has more critical situation due to its dry climate and inappropriate precipitation distribution spatially and temporally, also uneven distribution of population which is concentrate in small area. The only reasonable solution by considering water resources limitation and also restricted crop area is changing crop pattern to reach maximum or at least same amount of income by using same or less amount of water. The purpose of this study is to assess financial water productivity and optimize farmer’s income by changing in each crop acreage at basin and sub-basin level with no extra groundwater withdrawals, also in order to repair the damages which has enforce to groundwater resources during last decades a scenario of using only 80percent of renewable water were applied and crop area were optimize to provide maximum or same income for farmers.
Materials and methodsThe Neyshabour basin is located in northeast of Iran, the total geographical area of basin is 73,000 km2 consisting of 41,000 km2 plain and the rest of basin is mountains. This Basin is a part of Kalshoor catchment that is located in southern part of Binaloud heights and northeast of KavirMarkazi. In this study whole Neyshabour basin were divided into 199 sub-basins based on pervious study.Based on official reports, agriculture consumes around 93.5percent of the groundwater withdrawals in Neyshabour basin and mostly in irrigation fields, surface water resources share in total water resource withdrawals is about 4.2percent, which means that groundwater is a primary source of fresh water for different purposes and surface water has a minor role in providing water supply services in the Neyshabour basin. To determine crop cultivation area, major crops divided into two groups. two winter crops (Wheat and Barley) and two summer crops (Maize and Tomato). To accomplish land classification by using supervised method, a training area is needed, so different farms for each crop were chosen by consulting with official agricultural organization expert and multiple point read on GPS for each crop. The maximum likelihood (MLC) method was selected for the land cover classification. To estimate the amount of precipitation at each 199 sub-basins, 13 station data for precipitation were collected, these stations are including 11 pluviometry stations, one climatology station and one synoptic station. Actual evapotranspiration (ETa) is needed to estimate actual yield (Ya). Surface Energy Balance Algorithm for Land (SEBAL) technique were applied on Landsat 8 OLI images. To calculate actual ETa, the following steps in flowchart were modeled as tool in ArcGIS 10.3 and a spreadsheet file. To estimate actual crop yield, the suggested procedure by FAO-33 and FAO-66 were followed. Financial productivity could be defined in differently according to interest. In this study several of these definition was used. These definitions are Income productivity (IP) and Profit productivity (PP). To optimize crop area, linear programing technique were used.
Results and discussionaverage actual evapotranspiration result for each sub-basin are shown in context. In some sub-basins which there were no evapotranspiration are shown in white. And it happens in those sub-basins which assigned as desert in land classification. In figures 8 and 9 minimum amount of income and profit productivity for wheat and barley is negative, this number means in those area the value of precipitation is higher than value of evapotranspiration, so lower part of eq. 21 and 22 would be negative and in result water productivity would be negative. Since most of precipitation occurs during cold season of the year these numbers are expected. Two sub-basins of 43 and 82 has the value of negative, it means in these two sub-basins groundwater are recharging during the year 2014-2015.The maximum value of income and profit productivity belong to wheat and barley which are winter crops and mostly rain fed, so amount applied water would be so low and in result productivity increased. Among the summer crops maize has the most income and profit income which can be interpret due to their growing period and the crop types. Maize has around 110 days to reach to maturity and harvest, on the other hand tomato needs 145 days to harvest. Some plant is C3 and some are C4. C4 plants produce more biomass than C3 crops with same amount of water which leads to more productivity. The results showed that tomato should have the most changes in area reduction (0.2) and maize should have no changes in both scenarios. Crop area should reduce to 66percent of current cultivation area to maintain ground water level and only 6percent reduction in cultivation area would result in 20percent groundwater recharging.
Conclusion to save groundwater resources or even retrieve the only water resource, cultivation area must reduce if the crop pattern will not change. In this study only four crops were studied. It seems best solution is to introduce alternative crop.
Sahar Babaei Hessar; Qasem Hamdami; Hoda Ghasemieh
Abstract
Introduction: Groundwater is the most important resource of providing sanitary water for potable and household consumption. So continuous monitoring of groundwater level will play an important role in water resource management. But because of the large amount of information, evaluation of water table ...
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Introduction: Groundwater is the most important resource of providing sanitary water for potable and household consumption. So continuous monitoring of groundwater level will play an important role in water resource management. But because of the large amount of information, evaluation of water table is a costly and time consuming process. Therefore, in many studies, the data and information aren’t suitable and useful and so, must be neglected. The PCA technique is an optimized mathematical method that reserve data with the highest share in affirming variance with recognizing less important data and limits the original variables into to a few components. In this technique, variation factors called principle components are identified with considering data structures. Thus, variables those have the highest correlation coefficient with principal components are extracted as a result of identifying the components that create the greatest variance.
Materials and Methods: The study region has an area of approximately 962 Km2 and area located between 37º 21´ N to 37º 49´ N and 44º 57´ E to 45º 16´ E in West Azerbaijan province of Iran. This area placed along the mountainous north-west of the country, which ends with the plane Urmia Lake and has vast groundwater resources. However, recently the water table has been reduced considerably because of the exceeded exploitation as a result of urbanization and increased agricultural and horticultural land uses. In the present study, the annual water table datasets in 51wells monitored by Ministry of Energy during statistical periods of 2002-2011 were used to data analysis. In order to identify the effective wells in determination of groundwater level, the PCA technique was used. In this research to compute the relative importance of each well, 10 wells were identified with the nearest neighbor for each one. The number of wells (p) as a general rule must be less or equal to the maximum number of observations (n), here it is the number of years. So, for each well there are a 10 * 10 matrix. It should be noted in monitoring adjacent wells to a specific well, its dataset is not used. To quantify the effect of each well according to the number of its participation in the analysis and frequency of its effectiveness, each well is ranked. In the next step, the ineffective wells were recognized and eliminated using both the variation coefficient and Error criteria. Following, the procedure will be discussed.
Results Discussion: In this study, at first step using PCA technique wells were identified with a more than 0.9 correlation coefficient. Then each well ranked based on the relative importance and according to the specified thresholds, the variation coefficient and error of monitoring was estimated. The wells remain in threshold 1 led to the lowest variation coefficient, considered as effective wells in the evaluation of aquifer parameters. By eliminating ineffective wells at each threshold, the variation coefficient is reduced because of the elimination of wells with a greater difference in water depth compared to the average of whole wells. To check the certainty of obtained results, the error criteria were calculated for each threshold. According to the results, both variation coefficient and standard error of monitoring in threshold 1 come to be at least. Thus, 12 wells remain in the threshold 1 are considered as the important wells in monitoring the water table of plain Urmia. Monitoring error for these 12 wells is equal to 5.1 % which is negligible and can be introduced as index wells in sampling and estimation of groundwater table in plain Urmia. Using this method, instead measurements of water table in 51 wells it can be performed exclusively in the 12 wells.
Conclusion: Due to reduction of precipitation and unauthorized uses of groundwater resources, water table monitoring is very important in the accurate management of these resources. Because of extensive aquifers and large number of wells, water sampling and data collection is very time consuming and costly process, that leads to no economic justification in the lot of proceedings. Principal component analysis technique is suitable method to reduce sampling points and summarize information. In this study, at first step using PCA technique wells were identified with a more than 0.9 correlation coefficient. Then each well ranked based on the relative importance and according to the specified thresholds, the variation coefficient and error of monitoring was estimated. The results showed that the 12 wells remain in threshold 1. In this way, the cost, time and manpower required to measurements and analysis process cut into quarters.
Moslem Akbarzadeh; Bijan Ghahraman; Kamran Davary
Abstract
Introduction: For water resources monitoring, Evaluation of groundwater quality obtained via detailed analysis of pollution data. The most fundamental analysis is to identify the exact measurement of dangerous zones and homogenous station identification in terms of pollution. In case of quality evaluation, ...
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Introduction: For water resources monitoring, Evaluation of groundwater quality obtained via detailed analysis of pollution data. The most fundamental analysis is to identify the exact measurement of dangerous zones and homogenous station identification in terms of pollution. In case of quality evaluation, the monitoring improvement could be achieved via identifying homogenous wells in terms of pollution. Presenting a method for clustering is essential in large amounts of quality data for aquifer monitoring and quality evaluation, including identification of homogeneous stations of monitoring network and their clustering based on pollution. In this study, with the purpose of Mashhad aquifer quality evaluation, clustering have been studied based on Euclidean distance and Entropy criteria. Cluster analysis is the task of grouping a set of objects in such a way that objects in the same group (called a cluster) are more similar (in some sense or another) to each other than to those in other groups (clusters). SNI as a combined entropy measure for clustering calculated from dividing mutual information of two values (pollution index values) to the joint entropy. These measures apply as similar distance criteria for monitoring stations clustering.
Materials and Methods: First, nitrate data (as pollution index) and electrical conductivity (EC) (as covariate) collected from the related locational situation of 287 wells in statistical period 2002 to 2011. Having identified the outlying data and estimating non-observed points by spatial-temporal Kriging method and then standardizes them, the clustering process was carried out. A similar distance of wells calculated through a clustering process based on Euclidean distance and Entropy (SNI) criteria. This difference explained by characteristics such as the location of wells (longitude & latitude) and the pollution index (nitrate). Having obtained a similar distance of each well to others, the hierarchical clustering was used. After calculating the distance matrix, clustering of 287 monitoring stations (wells) was conducted. The optimal number of clusters was proposed. Finally, in order to compare methods, the validation criteria of homogeneity (linear-moment) were used. The research process, including spatial-temporal Kriging, clustering, silhouette score and homogeneity test was performed using R software (version 3.1.2). R is a programming language and software environment for statistical computing and graphics supported by R foundation for statistical computing.
Results and Discussion: Considering 4 clusters, the silhouette score for Euclidean distance criteria was obtained 0.989 and for entropy (SNI) was 0.746. In both methods, excellent structure was obtained by 4 clusters. Since the values of H1 and H2 are less, clusters will be more homogeneous. So the results show the superiority of clustering based on entropy (SNI) criteria. However, according to the results, it seems there is more homogeneity of clustering with Euclidean distance in terms of geography, but the measure of entropy (SNI) has better performance in terms of variability of nitrate pollution index. To prove the nitrate pollution index effectiveness in clusters with entropy criteria, the removal of nitrate index, the results was influenced by location index. Also, by removing index locations from clustering process it was found that in clusters with Euclidean distance criteria, the influence of nitrate values is much less. Also, compared to Euclidean distance, better performance was obtained by Entropy based on probability occurrence of nitrate values.
Conclusion: Results showed that the best clustering structure will obtain by 4 homogenous clusters. Considering wells distribution and average of the linear-moment, the method based on entropy criteria is superior to the Euclidean distance method. Nitrate variability also played a significant role in identification of homogeneous stations based on entropy. Therefore, we could identify homogenous wells in terms of nitrate pollution index variability based on entropy clustering, which would be an important and effective step in Mashhad aquifer monitoring and evaluation of its quality. Also, in order to evaluate and optimize the monitoring network, it could be emphasized on network optimization necessity and approach selection. Accordingly, less monitoring network clusters lead more homogeneous. Therefore the optimization approach will be justified from increasing to decreasing. In this case the monitoring costs, including drilling, equipment, sampling, maintenance and laboratory analysis, also reduce.
S.M. Hosseini-Moghari; K. Ebrahimi
Abstract
Introduction: Groundwater resources are the main source of fresh water in many parts of Iran. Groundwater resources are limited in quantity and recently due to increase of withdrawal, these resources are facing great stress. Considering groundwater resources scarcity, maintaining the quality of them ...
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Introduction: Groundwater resources are the main source of fresh water in many parts of Iran. Groundwater resources are limited in quantity and recently due to increase of withdrawal, these resources are facing great stress. Considering groundwater resources scarcity, maintaining the quality of them are vital. Traditional methods to evaluate water quality insist on determining water quality parameter and comparison between them and available standards. The decisions in these methods rely on just specific parameters, in order to overcome this issue, water quality indices (WQIs) are developed. Water quality indexes include a range of water quality parameters and using mathematical operation represent an index to classify water quality. Applying the classic WQI will cause deterministic and inflexible classifications associated with uncertainties and inaccuracies in knowledge and data. To overcome this shortcoming, using the fuzzy logic in water resources problems under uncertainty is highly recommended. In this paper, two approaches are adopted to assess the water quality status of the groundwater resources of a case study. The first approach determined the classification of water samples, whilst the second one focused on uncertainty of classification analysis with the aid of fuzzy logic. In this regard, the paper emphasizes on possibility of water quality assessment by developing a fuzzy-based quality index even if required parameters are inadequate.
Materials and Methods: The case study is located in the northwest of Markazi province, Saveh Plain covers an area of 3245 km2 and lies between 34º45′-35º03′N latitude and 50º08′-50º50′E longitudes. The average height of the study area is 1108 meter above mean sea level. The average precipitation amount is 213 mm while the mean annual temperature is 18.2oC. To provide a composite influence from individual water quality parameters on total water quality, WQI is employed. In other words, WQI is a weighting average of multiple parameters. The present research used nine water quality parameters (Table 2). In this paper Fuzzy Water Quality Indices (FWQIs) have been developed, involving fuzzy inference system (FIS), based on Mamdani Implication. Firstly, five linguistic scales, namely: Excellent, Good, Poor, Very poor, and Uselessness were taken into account, and then, with respect to ‘If→then’ rules the FWQIs were developed. Later, the seven developed FIS-based indexes were compared with a deterministic water quality index. Indeed seven FWQIs based on different water quality available parameters have been developed. Then developed indices were used to evaluate the water quality of 17 wells of Saveh Plain, Iran.
Results and Discussion: The present study analysed groundwater quality status of 17 wells of Saveh Plain using FWQI and WQI. Based on the driven results from WQI and its developed fuzzy index, similar performance was observed in most of the cases. Both of them indicated that the water quality in six wells including NO.1, 2, 6, 12, 13, and 17 were suitable for drinking. Due to the fact that the values of both indexes were under 100, the mentioned wells could be considered as drinking water supplies. The indexes illustrated the very poor quality of wells NO.7, 9, 10, 11, 14, and 16. As a result, according to FWQI1 along with WQI, nearly 35% of wells have proper drinking water quality, while approximately 30% and 35% of them suffered from poor and very poor quality, respectively. The overall picture of water quality within the study area was not satisfying, hence, an accurate site selection for discovering water recourses with appropriate quality for drinking purpose must be responsible authorities’ priority. Analysis of FWQI2, FWQI3 and FWQI4 revealed that elimination of the parameters slightly changed the result of FWQI2; however, FWQI3 and FWQI4 did not vary considerably. Thus, Cl influenced the water quality slightly, but Ca and K did not affect the water quality of the plain. The results showed that inexistence of one of the mentioned parameters would not affect the computational process adversely. A glance at FWQI5, FWQI6 and FWQI7 revealed the improper performance of FWQI5 to show wells’ water quality status. Throughout the FWQI5 evaluation process, all the wells’ water quality stood in Excellent category. Due to the considerable values of TDS in the Plain, elimination of this parameter in FWQI5 caused inappropriate evaluation. Hence, whenever a case study deals with a high value of a specific quality parameter, elimination of that parameter would negatively demote validation of the analysis. Figures (3)-(6) represented the results of WQI along with seven FWQIs for 17 utilized wells’ water quality assessment in the study area during the proposed periods.
Conclusion: Throughout the present study, the capability of seven FIS-based indexing procedures in modelling the water quality analysis of 17 wells of Save Plain was discussed. The proposed FWQIs were developed on the basis of Mamdani approach by applying triangular and trapezoidal membership functions to determine the groundwater quality of the case study according to the nine parameters. The results revealed that FWQI1-4 outperformed others. On the other hand, FWQI5-7 which eliminated three out of the nine parameters, did not made a valid contribution to the computational context. This might be related to omitting the effective water quality parameters from the inputs of the model. The results also illustrated that, only six out of 17 wells of the region could be considered as suitable sources for the drinking purpose. The water quality status in five wells was not satisfying, and six wells were plagued by very poor quality of water.
A. Pourhaghi; F. Radmanesh; A. Maleki
Abstract
Introduction : Sustainable development of groundwater resourcesrequires a proper assessment of available resources, understanding of system behavior and interaction between groundwater and surface water.In recent years, a Delfan plain (in Iran) is facing a sharp decline in groundwater levels due to increasing ...
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Introduction : Sustainable development of groundwater resourcesrequires a proper assessment of available resources, understanding of system behavior and interaction between groundwater and surface water.In recent years, a Delfan plain (in Iran) is facing a sharp decline in groundwater levels due to increasing in population and exploitation of groundwater resources.In this study, using modflow model effect of drought and wet conditions on water table fluctuations of Delfan plain aquifer was evaluated.
Materials and Methods: Delfan plain is one of the Lorestan Plains (in Iran Country) and located in the north of the Lorestan Province, around the city ofNurabad (Delfan).Precipitation survey of the region shows that the average annual rainfall in the plains is 480 mm and aquifers of the region has 10 piezometric wells. Drawing of the groundwater hydrograph from 2004 to 2013 shows that the general trend of the groundwater level is downward, which represent decreasing in groundwater resources of the region. At the beginning of the modeling process using Modflow model, after gathering all the required information, conceptual model of the plain was generated. To preparing this model, various data such as topographic maps, geophysical data, logs of wells, pumping tests and observation wells data and flow data taken from exploitation wells was used. Water level data of October 2007 which has the lowest fluctuation was used for the calibration of steady state.In this step with model successive run, hydraulic conductivity is optimized. After model calibration in the steady state, do same in the unsteady state.Specific discharge was optimized at this step.After calibration in the unsteady state, model needs verification to be trusted.For this purpose, verification was done in November 2012 to November 2014.After calibration and validation of the model, the model was carried out under drought and wet conditions.Drought is one of the environmental disasters that its occurrence could bring the water challenges in the field of quality and quantity. Because of drought and lack of rainfall affect groundwater resources, soil moisture and river flow, used index called Standard Precipitation Index (SPI) to quantify the impact of rainfall in of 3, 6, 12, 24-month period.This index is calculated based on long-term statistics.
Results Discussion :In steady state, the model's sensitivity is studied according to changes in hydraulic conductivity value and discharge of pumping wells and in the unsteady state according to specific yield and other parameters was investigated. Based on this analysis in steady state, generally it can be said that the model is more sensitive to the exploitation wells. In unsteady state, the model is more sensitive to specific yield and hydraulic conductivity and other parameters are in the next level.With SPI reviewing of 120-months, it was seen that the plain in 1984 and 1993 has the lowest 120-month SPI with the value of -1.08 (with average precipitation value of 423 mm).For applying virtual wet period with 30-years precipitation reviewing, it was observed that years of 2001 and 2010 have the most 120-month SPI value with value of 1.86 (with average precipitation value of 587 mm).For applying the virtual wet conditions in the next step, the model was simulated with the rainfall data of 2001 and 2010.To decrease the water table drop, considering the amount of drop and water needs of the region, several runs were performed which ultimately results showed to offset the drop in these three exploitation areas, the discharge of exploitation wells must be reduce 20% that This strategy is able to reduce the average annual rate of water table drop for the next 10 years. Finally, after model’s run and piezometers drop, plain model was used to obtain groundwater balance.
Conclusion: The model implementation in drought and wet conditions shows that in these conditions the groundwater level decreases with the average of (-7.80m) and (-5.83m), respectively. which with the 20 % decrease of the discharge of the exploitation wells in these conditions, the level groundwater and aquifer balance improves.For the next ten years in the normal condition or present situation of exploitation, plain balance is -83.20 million cubic meters which by 20% reduction in wells exploitation, this water balance is predicted -41.20 million cubic meters for next 10 years.In the drought conditions Delfan aquifer water balance is predicted as -91.20 million cubic meters during ten years which by 20% reduction of wells exploitation this water balance increases to -49.20 million cubic meters.
A. Khashei Siuki; B. Ghahraman; M. Kouchakzadeh
Abstract
Nayshabour plain in Khorasan Razavi with arid and semi-arid climate, have an important role in agricultural production by using groundwater resources. In this study, by using groundwater balance model the equations which are required for estimating water table variations is obtained for plain. afterwards ...
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Nayshabour plain in Khorasan Razavi with arid and semi-arid climate, have an important role in agricultural production by using groundwater resources. In this study, by using groundwater balance model the equations which are required for estimating water table variations is obtained for plain. afterwards since, there are too many variables in the objective function of water consumption(optimized crop pattern and intensification) a meta heuristic method which require less computation of effect while it is more efficient will be used. In this research PSO optimization algorithm (Particle Swarm Optimization) is used. Model results based on a normal year (2008) showed that can earn highest income from the aquifer with 30 percent reduced spring cultivation, and increased 30 percent of wheat, barley and calona. Among the spring crops, corn and tomato ratio to another crops have largest increase area. The results showed that can obtain 7500 (thousands rial /hec)more benefit with increasing 20,591 hectares to autumn crops and reduced 10,970 spring products
