جستجوی مقالات مرتبط با کلیدواژه "آسیب پذیری آب های زیرزمینی" در نشریات گروه "منابع طبیعی"

The state of groundwater pollution in Torghabeh-Shandiz watershed of Khorasan County has become a major problem, particularly in respect of the increasing population, and the agricultural, industrial and commercial development. The present work attempts to interpret the groundwater vulnerability of this watershed using the DRASTIC model together with the geographic information system (GIS). The data which correspond to the seven parameters (depth to water level, net recharge, aquifer media, soil media, topography, the impact of vadose zone and hydraulic conductivity) of the DRASTIC model were collected and converted into thematic maps with GIS. The study showed that the DRASTIC index shows lies in the range of 68 to 225 which were classified into five zones, very low, low, moderate, high, and very high-risk zone of groundwater contamination. The DRASTIC map illustrates that an area of 15.9% is a very low vulnerability, 20.29% low vulnerability, 26.33% moderate vulnerability, 24.34% high vulnerability and 13.14% very high vulnerability in the study area. The river flows from the northeast region of the watershed allows more recharge of water, which may drain the fertilizers from the surrounding agricultural lands along with it to the groundwater and hence leads to groundwater vulnerability of this region. To check the reliability of the DRASTIC index map in the field condition, groundwater samples were collected for the analysis of nitrate (NO3) which is found as one of the pollutants in groundwater resulting due to use of fertilizers during agriculture. The presence of high nitrate concentration over high to moderate risk pollution zone in the study area validated satisfactorily.

Aquifer vulnerability assessment to identify areas that have a potential contamination of water re-sources management, is very important. One of the rudimentary and important ways to prevent groundwater contamination is the identification of vulnerable areas and applied its results for land use management. In this study, the vulnerability of Ramhormoz aquifer evaluated by an Analytic hierarchy process (AHP) method and Modified DRASTIC based on GIS. In the DRASTIC model the map of seven hydrogeological characteristics affecting groundwater pollution (depth to water, net recharge, aquifer media, soil type, topography, the impact of vadose zone and hydraulic conduc-tivity) was combined using Geographic information system (GIS) and aquifer vulnerability map was prepared. In order to overlaying the data layer tree methods (DRASTIC-DRASTIC, DRASTIC-AHP and AHP-AHP methods) have been used. Nitrate concentration data of groundwater have been used for model validation. The results show that, except the southeast that have a high vulnerability, other parts of plain have a low to moderate vulnerability. In the study area, DRASTIC-DRASTIC and DRASTIC-AHP methods have a better results rather than AHP-AHP method. The correlation coefficient between Q index and nitrate concentration in DRASTIC-DRASTIC, DRASTIC-AHP and AHP-AHP methods is obtained 0.97, 0.96 and 0.81, respectively, which confirmed the results.