Mohammad Saeidi; Mehdi Komasi; Shahab Hasanpor
Abstract
Over the past few decades, as a result, population growth, industrialization, urbanization, etc., demand for water has increased, most of these requirements have provided by exploiting groundwater resources. Therefore, the uncertainty in the demand and supply of water should be minimized by proper groundwater ...
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Over the past few decades, as a result, population growth, industrialization, urbanization, etc., demand for water has increased, most of these requirements have provided by exploiting groundwater resources. Therefore, the uncertainty in the demand and supply of water should be minimized by proper groundwater management, by identifying areas with groundwater potential. In this study, it has been attempted to find the potential groundwater resources in Silakhor plain using combined Analytical Hierarchy Process (AHP) and fuzzy TOPSIS method in GIS environment. In this regard, eleven thematic layers including layers of lithology, rainfall, vegetation cover, lineament density and distance, elevation, slope, land surface temperature, land use and drainage density and distance were prepared based on satellite image processing and statistical data, used to create a groundwater resource potential mapping. Groundwater resource potential map was classified into five categories including high, good, medium, low and very low potential. Accordingly, the high to moderate potential sites are located more in the center and southwest of the plain and correspond to quaternary alluvial and carbonate hard rocks zones. Validation was done by the number of wells in the area and the results indicate that the use of an integrated approach AHP and Fuzzy TOPSIS methods in groundwater potential mapping with the location of the wells is in good agreement, about 87% of the wells are located in areas with moderate to high groundwater potential.
Mehdi Komasi; Soroush Sharghi; Vahid Nourani
Volume 3, Issue 9 , March 2017, , Pages 63-86
Abstract
Time series analysis of hydrological processes plays an important role in accurate recognition of this process. Wavelet-entropy index is a new indicator to assess the fluctuations of time series. In this paper, the effective factor in groundwater level declining in the Silakhor plain is examined using ...
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Time series analysis of hydrological processes plays an important role in accurate recognition of this process. Wavelet-entropy index is a new indicator to assess the fluctuations of time series. In this paper, the effective factor in groundwater level declining in the Silakhor plain is examined using wavelet-entropy index. Generally, wavelet-entropy index reduction or time series complexity reduction of a phenomenon, indicates the reduction in time series natural fluctuations and thus the occurrence of an unfavorable trend in time series. In this way, to identify the main cause of declining aquifer water table, firstly, monthly time series of precipitation, temperature and rivers flow of this plain divided into shorter time periods and then, each of these time series were decomposed to multiple frequent time series by wavelet transform and then, normalized wavelet energies were calculated for these decomposed time series and finally, wavelet-entropy index was calculated for each three different time periods. The results of wavelet-entropy index analysis reflect the fact that, the complexity reduction of the flow time series about 71% is more effective on groundwater time series complexity reducing compared to the complexity reduction of the precipitation and temperature time series about 13% and 10.5% respectively. This result indicates the primacy of the human factors compared with the climate change factors impacts in declining the groundwater level in this plain.
