نوع مقاله : مقاله پژوهشی
نویسندگان
1 کارشناسی ارشد منابع آب دانشکدة کشاورزی دانشگاه تبریز
2 دانشیار منابع آب دانشکدة کشاورزی دانشگاه تبریز
3 استادیار منابع آب دانشکدة کشاورزی دانشگاه شهرکرد
4 استادیار منابع آب دانشکدة کشاورزی دانشگاه تبریز
چکیده
کلیدواژهها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
A study of changes in groundwater resources of Najafabad plain is an important issue as
regards water resources management, especially after dry becoming of Zayandehrood
River. In the present study trend analysis was conducted on groundwater level of 33
piezometeric stations, located in Najafabad plain during 1374-1391 while using Mann-
Kendall non-parametric test. The slope of trend line was estimated through Sen’s
estimator method for each time series. Homogeneity of trends was tested using Van Belle
and Hughes method. Results indicated that trends of groundwater level for all the stations
(except stations located out of drainage and irrigation networks) were significantly
negative. Significantly negative trends (P<0.1) were exhibited for above 52 percent of
stations. Results of trend line slopes revealed that on the average, groundwater level of
Najafabad plain declined for about 32 cm/year. The strongest decline belonged to Kahrizsang-
jadid Station, which declined for about 5.92 m/year. Results of homogeneity of the
trends indicated that trends were homogeneous for monthly periods, but heterogeneous
for stations. Results of trend maps showed that a maximum level of groundwater changes
occurred on drainage and irrigation network sites. The isopiz maps showed that some
stations located on the drainage and irrigation network range sites had declined for about
50 to 100 meters in the recent 17-years. The results of MK4 method (significant at 1%
level) were chosen for Pettitt Test. Pettitt Test was done on data series which showed that
during 1999-2002 and year 2007 a maximum downward jump occurred in Najafabad
groundwater level series and knowing that in these years Zayandehrood river had be dried
for political reasons. Diagram of Pettitt Test was plotted with the mean before jump and
that after jump as specified on the diagram. The diagram revealed that the difference
between mean before vs. after jump of the groundwater level series, was 50-100 meters,
indicating the phenomenon as being a disaster for Najafabad plain.
کلیدواژهها [English]