جستجوی مقالات مرتبط با کلیدواژه « mann-kendall test » در نشریات گروه « مهندسی آب »

The permanent exploitation of groundwater requires adopting appropriate policies for the quantitative and qualitative protection of this valuable resource. Considering the reliance of a part of the development plans of Mazandaran province on groundwater, in this research, the sustainability and trend of groundwater depth (GWD) changes were investigated in the 1991 to 2020 period (1991 to 2000: first decade, 2001 to 2010: second decade, 2011-2020: third decade). Mann-Kendall test and Sen’s slope estimator were used for trend analysis. Groundwater sustainability was assessed using four indicators including, renewable groundwater per capita (GWRRp), total abstraction of groundwater/groundwater recharge (TAGR), total abstraction of groundwater/exploitation of groundwater resource (TAGE), and water exploitation index (WEI). The values of the Man-Kendall statistic ranged from -2.50 to 3.76, indicating the increasing trend of GWD during the last 30 years in all areas except Babol-Amol (second and third decades) and Noor-Nooshahr (third decade). During the first and second decades, the amount of GWD in Mazandaran province increased by 0.21 and 0.12 meters per year, respectively. According to GWRRP, TAGR, and TAGE indicators, the west of Mazandaran had better conditions than the central and eastern regions of the province. Based on the WEI indicator, Ramsar-Chalous and Noor-Nooshahr areas (WEI<10), Behshahr-Bandargaz, Babol-Amol and Sari-Neka areas (10<WEI<20), and Qaemshahr-Joybar area (WEI>20) were in a satisfactory, worrying and critical condition, respectively. Based on the results, the groundwater situation in a large part of Mazandaran is unsustainable and requires the adoption of appropriate management strategies to prevent the increase in this unsustainability.

Groundwater resources due to lately affected by climate changes and precipitation fluctuations are valuable. Given that the interaction between climate and groundwater components are more complicated than interaction between climate and surface waters components, therefore investigation of changes in groundwater has an important role in planning and sustainable water resources management In this research, trend of groundwater, precipitation and stream flow time series in monthly, seasonal and annual time scales and dominant periods of trend in original time series for stations located in Azarshahr plain, East Azerbaijan Province and part of the watershed of Urmia Lake were found by using the hybrid Mann-Kendall method with wavelet transform during 45 years. Results showed that, all the stations have a downward trend for all the time scale studied. Accurately, in the results, 16 months, 6 months and 8 years periods were detected as dominant periods for groundwater time series in monthly, seasonally and annual scales, respectively. According to sequential Mann-Kendall results, it can be obtained that a decreasing trend starts from 1378 in the stations. In addition, Sen’s method was used to confirm the proposed MK test and its accuracy was confirmed.

The aim of this study was the evaluation of drought effects through SPI index assessment on the water quality of the Dez River. For the determining the drought, ten-year meteorological data (2005-2014) were achieved through the weather stations of Hussainiya, Dezful, and Shush and for impact evaluation of drought on the water quality of the Dez River, discharge statistics and qualitative parameters related to seven hydrometric stations along the Dez River achieved through Khuzestan Water And Power Authority. The mean frequency of dissolved anions and cations in the hydrometric stations of the Dez River achieved like HCO3>SO4>Cl and Ca>Na>Mg. The variance analysis of the water qualitative parameters showed that the effect of station and year on the amounts of discharge, EC, TDS, SARIW, pH, Cl, HCO3, Ca, Mg, Na, and SO4 had a significant difference (P

In this study, the trend of water quality variables of Sosan and Gotvand hydrometer stations were estimated to evaluation the effectives of Gotvand's dam on Karoon River. The water quality variables are TDS, EC, pH and SAR in period of 1998 to 2012. The results of modified Mann-Kendall test for Sosan station showed that the TDS variable was seen the increasing and decreasing trend in monthly scale. Between all months, the August has the most significant increasing trend in TDS variable and with attention to the calculated the Sen slope, this variable was increased about 180.32 (mg/l) in resent 16 years. In annual scale, also the trend of TDS was calculated as non-significant increasing. Also the trend of EC variable in Sosan station was same as TDS and has a non-significant increasing trend in most of months. In annual scale also was seen the increasing trend in EC variable. GThe results of modified Mann-Kendall test for Gotvand station showed the decreasing trend in the water quality of Karon River after the Gotvand's dam. TDS variable has a increasing and decreasing trend in Gotvand station in monthly scale. EC variable in Gotvand station in all of months has a increasing trend. The results of evaluation the time of changing trend showed that the most significant failure occurred in year 2007. The results of chemical analysis of water quality in the Karun River gauging stations showed that from 2001 to 21013 the values of EC were increased about 160 percent.