پهنه بندی تراز آب زیرزمینی دشت مرند بر اساس پتانسیل های موجود (مقاله علمی وزارت علوم)
درجه علمی: نشریه علمی (وزارت علوم)
آرشیو
چکیده
سطح و کیفیت آب های زیر زمینی در ارتباط با متغیرهای مختلف تغییر می کند. هدف از این تحقیق، تخمین تغییرات زمانی و مکانی تراز آب زیرزمینی دشت مرند می باشد. برای این منظور، محاسبات بی لان آبی در نرم افزار Excel و پهنه ب ندی مکانی تغییرات در ArcGIS انجام شد. نتایج بررسی ها در وضعیت موجود نشان می دهد که در دوره ی آماری 32 ساله تراز آب زیرزمینی دشت به طور متوسط با افتی معادل 52 سانتی متر در سال و در 10 سال اخیر ب ه طور متوسط با افتی معادل 48 سانتی متر در سال روب رو شده است. برای بررسی روند تغییرات تراز آب زیرزمینی دشت در سال های آتی، ابتدا آبخوان دشت مرند به چهار پهنه ی مختلف تقسیم و سپس سه سناریو به صورت، 1) تأمین همه ی مصارف از منابع آب زیرزمینی، 2) تأمین مصارف شرب و صنعت از رودخانه ی ارس، 3) تأمین مصارف شرب و صنعت از رودخانه ی ارس و اعمال مدیریت مصرف بهینه تعریف شد و در نهایت برای هر یک از سناریوها، تراز آب زیرزمینی دشت در شهریور 1393 و 1398 پهنه بندی گردید. نتایج بررسی ها نشان می دهد که در سناریوی اول، با تشدید افت سطح آب زیرزمینی در تمامی پهنه ها، وضعیت آبخوان بحرانی تر شده و افت تراز آب زیرزمینی در برخی نواحی به 6/2 متر می رسد. با اعمال سناریوی دوم، تراز آب زیرزمینی دشت حداقل 67/1 و حداکثر 93/1 متر افزایش می یابد و با ادامه این روند بعد از 14 سال آبخوان به وضعیت سال 1384 برمی گردد. همچنین با اعمال سناریوی سوم تراز آب دشت، حداقل 78/4 متر و حداکثر 29/5 متر افزایش می یابد که با ادامه این روند بعد از 5 سال آبخوان به وضعیت سال 1384 برمی گردد.The Zoning of Groundwater Level in the Marand Plain Based on the Existing Potential
Introduction
Due to an intense loss in groundwater level and a high decrease in reservoir capacity, the Marand plain has been banned since 1991. However, since 1994, the groundwater level been dropping year by year. As a result, many wells and qanats have been dried or their discharge capacity has been decreased, which has caused a lot of problems for the operating organizations. In this study, to investigate and manage the groundwater level variation in the Marand plain, three scenarios including supplying all consumption from groundwater resources, supplying drinking and industry consumption from the Aras River, and supplying drinking and industry consumption from the Aras River and applying the optimal management of the consumption for agricultural uses were defined. The water balance equation was used to establish the relationship between input, output, storage in an aquifer, and a variation of groundwater level in the Marand plain was estimated based on the available data (2005-2014). Finally, the zoning of the groundwater level was done for the September 1398 and the results were compared with the September 1393.
Methodology
In this research, the Marand plain with an area of 562.22 km2 in the northwest of East Azerbaijan province was selected as a case study. Investigating the hydrological and meteorological parameters of the Marand plain between the years 1982 and 2013 showed that the average annual precipitation was 283 mm, the average annual temperature was 12.8°C, and the average annual pan evaporation was 104 mm. The aim of this research was to estimate the spatial and temporal variation of the groundwater level of the Marand plain. For this purpose, the water balance estimation was done by using Excel and the zoning of groundwater level variation was done by using ArcGIS. A groundwater level analysis of the Marand plain was carried out based on the 50 observations of wells during 2005 to 2014. In this period, according to the groundwater level data, the aquifer parameters, such as the loss of the groundwater level and the amount of water withdrawal from the aquifer were determined. Then, various scenarios were defined for assessing the status of the aquifer.
Result and Discussion
The analysis of the groundwater level in the Marand Plain in a year statistical period (1982-2013) showed that the groundwater level of the plain had decreased about 16.56 m. Also the average annual groundwater level of the plain decreased about 48 cm between the years 2005 and 2015.
By applying the first scenario, in the next five years, the fall of the groundwater level in the zone 1 will be 2.35 m, in the zone 2 will be 2.25m, in the zone 3 will be 2.6m, and in the zone 4 will be 2.45m.
Also the area of the zone 4 had increased from 246 km2 to 252 km2 which indicated a further fall of the groundwater level in a large area of the plain. By applying the second scenario, in the next five years, the growth of the groundwater level in the zone 1 will be 1.74 m, in the zone 2 will be 1.67 m, in the zone 3 will be 1.93 m, and in the zone 4 will be 1.82 m. Indeed, following this trend, the groundwater level after 14 years will return to the situation of 10 years ago (2005). In addition, after 46 years, it will return to the situation of 32 years ago (1982). By applying the third scenario, in the next five years, the growth of the groundwater level in the zone 1 will be 4.78 m, in the zone 2 will be 4.58 m, in the zone 3 will be 5.29 m, and in the zone 4 will be 4.99 m. Following this trend, the groundwater level after 5 years will return to the situation of 10 years ago (2005). After 17 years, it will return to the situation of 32 years ago (1982).
Conclusion
The aim of this research was to estimate the spatial and temporal variation of the groundwater level in the Marand plain. The results showed that the annual average groundwater level had decreased 48 cm/year between the years 2005 and 2014. Also by applying the first scenario, with an intensified decline in the groundwater level in all zones, the status of the Marand aquifer becomes more critical. For example, in some areas, the groundwater level will decease about 2.6 m. By applying the second scenario, the groundwater level will increase at least 1.67 m and utmost 1.93m and by following this trend, after 14 years, the aquifer will return to the situation of 2005. Also by applying the third scenario, the groundwater level will increase at least 4.78 m and utmost 5.29m and by following this trend, after 5 years, the aquifer will return to the situation of 2005.
تبلیغات
