اندرکنش آب‌های سطحی و زیرزمینی در تالاب قره‌قشلاق ساحل جنوب شرقی دریاچه ارومیه

تغییرات زمانی و مکانی اندرکنش آب های سطحی و زیرزمینی در تالاب ها، به منزله یکی از زیست بوم های آبی مهم، بسیار زیاد و پیچیده است. در محیط های خشک و نیمه خشک، که میزان بارش های جو ّی بسیار متغیر و به میزان چشمگیری کمتر از میزان تبخیر است، آب های زیرزمینی عامل اصلی تعادل و حفظ محیط زیست تالاب ها هستند. در این تحقیق تلاش شد با شناخت بهتر میزان و نحوه تغییرات در اندرکنش آب های سطحی و زیرزمینی تالاب قره قشلاق میزان آسیب پذیری این زیست بوم ارزشمند بررسی شود. این تالاب از نوع تالاب های ساحلی است و در انتهای مسیر رودخانه های مردوق چای و زرینه رود در جنوب شرقی دریاچه ارومیه قرار دارد. تالاب های انتهایی، مانند این تالاب، به دلیل نداشتن سازوکار حذف نمک، چنانچه در معرض ورود آب شور قرار گیرند، نسبت به سایر تالاب ها آسیب بیشتری می بینند. در این پژوهش با ترسیم جهت جریان آب زیرزمینی در زمان های مختلف این نتیجه به دست آمد که تالاب قره قشلاق از آبخوان های بالادست خود تغذیه می شود. با استفاده از قانون دارسی، میزان آب زیرزمینی ورودی به تالاب در سال آبی 1394 1395 حدود 0.738 میلیون متر مکعب برآورد شد. در روش دیگر، با استفاده از میزان ایزوتوپ های پایدار دوتریم و اکسیژن 18، مقدار آب زیرزمینی ورودی در سال یادشده به ترتیب 802/0 و 558/0 میلیون متر مکعب بر سال تخمین زده شد. ارزیابی مولفه های بیلان آب در تالاب قره قشلاق نشان می دهد حدود 20 درصد از آب این تالاب در سال آبی 1394 1395 با آب زیرزمینی تامین شده است.

Interaction of Surface water and Groundwater in Gareh Gheshlagh Wetland, Southeast of Urmia Lake

In this research, a sequential Gaussian simulation method has been used to determine the permeable zones in the hardrock aquifer of the GohrZamin open pit mine. For this purpose, 4946 RQD data from eightyseven exploratory boreholes was used and exploratoryspatial data analysis of these data was performed using the preliminary statistics, location maps, histograms and variograms. Results of preliminary statistics show that this variable has not a normal distribution and that the statistical parameters are not significantly affected considering the declustering weights. The RQD data was transformed to a normal distribution with a Gaussian transform. In the next step, the omnidirectional/directional experimental variograms of RQD data were calculated and modeled using the standard models. Three directions of (1) Azimuth 0Dip 0, (2) Azimuth 90 Dip 0 and (3) Dip 90 show the best spatial continuity. These variograms were combined together in a one single model. The highest spatial continuity is in the eastwest direction compared to the other two directions. Finally, the sequential Gaussian simulation of RQD variable was performed using the 3D modeled variogram and normalized data. A probability map was generated using the results of 100 simultaions. Results show that the southeastern, southwest, and western parts of the mine pit are the best places for drilling new pumping wells.IntroductionGoharZamin iron ore mine is located in 50 km southwest of Sirjan city in Kerman province. Due to the tectonic condition, fracture and fissure in the hardrock aquifer of area, the groundwater has been concentrated on the pit mine. Therefore, identifying the permeable zones is essential to mine dewatering process.Materials and methodsIn this research, ISATIS software has been used to sequential Gaussian geostatistical simulation. The exploratoryspatial data analysis was performed including preliminary statistics, location map, histogram and variograms of RQD values. Then the cell declustring method is used to decluster the RQD variable. Moreover, Gaussian transform method is applied to data normalization. In order to investigate the spatial continuity of the RQD variable, the omnidirectional and directional variograms were generated. Finally, sequential Gaussian simulation as well as simulation uncertainty analysis have been performed using threedimensional variograms of the RQD normal values.Results and discussionIt is clear from the indicator maps that high RQD values are concentrated in the south of pit and deeper levels. It is influenced by the shape of the iron ore deposit. According to the value of skewness and kurtosis coefficients of RQD, it seems that this variable do not has the normal distribution. The 3D variogram on the XY, XZ and YZ planes indicate (a) lower spatial continuity in the northsouth direction relative to the eastwest direction, (b) spatial continuity in the easternwestern axis is greater than the Z axis and (c) spatial continuity in the Y direction is greater than the Z direction. The final floor level in the pit is very important for designing and determining the position of pumping wells to dewatering process. Therefore, results of 100 simulations were overplayed. The mean values of simulations calculated from the final floor level in the pit to the top of hardrock aquifer. It was observed that at each elevation, minimum of RQD were concentrated in certain regions. These maps can be used to determine the high permeable zone.Also, two main strikeslip faults with an almost NWSE and EW trend, pass through the southern part of pit. These fults and crush zones are located almost in the same direction.ConclusionAccording to the results of study, the RQD variable does not follow the standard distribution and declustering weight on the data did not have much effect on the mean value. It indicats a fairly uniform distribution of RQD data in the study area. Omindirectional and directional variograms of the RQD variable (normal values) showed that this variable has good spatial continuity. Moreover, the threedimensional variogram of the RQD indicated that the EW direction has the highest spatial continuity relative to the two NS and Z directions. While, the spatial continuity in the NS direction is more than the spatial continuity in Z direction. Results showed two straightslip faults with NWSE and EW trends are located in the south of pit and These have important role in greating the crushed and permeable zones. Sequential Gaussian simulation and uncertainty maps in various parts of the pit showed that regions of southeast, southwest, and west of the pit have the highest probability is the low RQD and the high permeability.