مخاطرات محیط طبیعی (Dec 2022)
Modeling the subsidence development of Marvdasht plain in relation to groundwater abstraction
Abstract
Excessive abstraction of groundwater aquifers in the country has caused a sharp drop in the aquifer water level and the loss of aquatic aquifers, the effects of which is the phenomenon of subsidence. In this study, simulation of groundwater level changes in Marvdasht-Kharameh basin from a validation period and processing of a large set of raw data in Modflow mathematical model was used. The output results of sensitivity analysis of effective parameters in the calibration of Marvdasht aquifer show the maximum effect of hydraulic conductivity parameters and horizontal hydraulic conductance anisotropy and a set of linear groups of water supply network. Therefore, it is in line with the statistics of the Fars Regional Water Organization that there are wells with high discharge in these areas. According to the conditions of the aquifer, if the current operation trend continues, it is predicted that the groundwater level will drop by 15 meters during the years 2019 to 2029. Also, according to the average land subsidence, which averages 0.76 meters per 10 meters. The average land subsidence with the current harvest trend in the next ten years is predictable 114.78 cm and with a 30% increase in harvest, the rate of aquifer decline over the next 20 years is about 37 meters with an annual decline of about It is 1.9 meters. Land subsidence in this case is also predicted to be about 280 cm. Finally, according to the maps prepared from Marvdasht aquifer, due to the alluvial nature of the groundwater aquifer, the effect of water level drop can be observed from a short distance. The rate of subsidence in the southern and southwestern margins of the plain due to the low thickness of sediments and in the northern and northeastern parts of the plain due to coarse-grained sediments, is less than the central parts of the plain.
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