بررسي و ارزيابي سناريوهاي مديريتي احيا و تعادل بخشي آب هاي زيرزميني در راستاي كاهش فرونشست زمين، مطالعه ي موردي: آبخوان دامنه و داران

چكيده انگليسي :

Investigation and Assessment of Management Scenarios for Groundwater Rehabilitation to Reduction of Land Subsidence Case study Damane Daran Sub basin Marziyeh Khajeali m khajeali@cv iut ac ir Date of Submission 2019 06 22 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor H R Safavi hasafavi@cc iut ac ir AbstractPopulation growth and consequently the extension of water demands caused sharp increasing water use in theagricultural and industrial sectors This increase in demands which has been accompanied by an increase in the rateof groundwater extraction caused irreparable damage Land subsidence caused by groundwater exploitation is oneof the most critical issues that many countries in the world now get involved as a big problem For instance in thepast two decades the Damane Daaran aquifer in Gavkhoni river basin has been abandoned due to the land subsidencecaused by the over extraction of groundwater The occurrence of subsidence is because of the drawdown due to theextraction of groundwater so that water from the pores of the soil will be evacuated because of the pressure of theupper layers The subsidence will become more critical if the over extraction of groundwater causes the aquifer tomiss the elastic behavior in which case the changes will become inelastic and the possibility of the aquiferrehabilitation will be eliminated In this research groundwater rehabilitation to the reduction of land subsidence ispresented assessed and analyzed Therefore a modeling tool has been used to understand the behavior of aquifer First a groundwater flow model was developed in ModelMuse software from 2011 to 2018 water year with thecalibration validation in steady state and unsteady state condition and the period of 2019 to 2024 for prediction Subsequently the SWT package was used in ModelMuse software to model land subsidence and the calibration validation and prediction had done For calibration and validation of land subsidence modeling the process resultsof 52 Sentinel 1 satellite images were used The high rate of land subsidence in the aquifer especially in agriculturalland determines the necessity of management scenarios to reduce this phenomenon Presented scenarios are 1 continuation of an existing trend 2 4 respectively 25 50 and 75 reduction in groundwater extraction fromwells 5 A 200 increase in recharge rates of critical areas After the implementation of each scenario on landsubsidence model their effects on decreasing land subsidence rates are assessed and analyzed by comparing withscenario1 then compared with other scenarios to ranking them The results show that the general trend of landsubsidence complies with the process of changes in the water level which is nonlinear and involves other factorssuch as thickness storage properties and the thickness of interbeds and so on Therefore it can be said that pumpingreduction scenarios will have a significant effect on controlling land subsidence The results show that if the currentprocess of groundwater extraction continues the maximum land subsidence will be 0 65m while in the case ofscenarios 2 to 4 this value will be 0 52 0 41 and 0 31m respectively so that with the implementation of scenario 4 the subsidence rate is almost zero Also the average drawdown in the aquifer in scenario 1 is 11 5 m and this valuewill be reduced under the scenarios 2 4 to 10 7 5 and 4 15 m respectively These scenarios can be implemented bylowering the crop area or changing the crop pattern by planting the products with lesser water requirements On theother hand scenario 5 was only effective for the quantity rehabilitation of aquifer and not for reduction of landsubsidence rate so that under this scenario the maximum land subsidence reached 0 65 m which is almost constantrelative to scenario 1 and the average drawdown was 10 2 m that was 1 3 m lower than scenario 1 In this case thequantity of groundwater rehabilitation is due to

خواجه علي، مرضيه

بررسي و ارزيابي سناريوهاي مديريتي احيا و تعادل بخشي آب هاي زيرزميني در راستاي كاهش فرونشست زمين، مطالعه ي موردي: آبخوان دامنه و داران

فرونشست زمين , دامنه و داران , احيا و تعادل بخشي آبخوان , نرم افزار ModelMuse , شبيه سازي كمي آب زيرزميني , تحليل سناريو