International Journal of Ground Sediment & Water

247-263

Authors: Adnan Khan*, Asal EghbalBakhtiari

Present study is aimed at assessing the groundwater quality in coastal part of Karachi and detection of seawater intrusion through major ion geochemistry of the coastal groundwater occurring in Korangi and DHA areas. For this purpose 6 groundwater samples were collected from deep wells (mean depth: 600ft) of Korangi and DHA phase VIII. Groundwater pH is slightly variable which ranges between acidic to alkaline (6.6-8.5) with a mean of 7.7. The groundwater is classified as moderate to highly saline (mean TDS: 21234 mg/L) and very hard (hardness: 3221.3 mg/L). Hydro-geochemical analysis of collected samples revealed that the dominant hydrofacies in the groundwater is Na-Cl. In addition, excess of Ca and Mg followed by dominance of Cl over alkali ions suggest that the groundwater is highly saline mixed through sea water intrusion. The overall major ion chemistry reveals that such groundwater is not suitable for domestic purpose. © International Journal of Ground Sediment & Water, @ Sun Jichao. The website is https://ijgsw.eu.org/ http://ijgsw.net/

277-292

Authors: Mohammad Sadegh Sadeghian, Mohammad Daneshkhah, Mohammad Heydari

Sedimentation of dams in Iran is an important issue. Often the sedimentation prediction is done in different ways in dams’ design. Sometimes due to lack of data of sedimentation, the calculations lead to false results. To compare the predictions made as to whether the design is correct or not a method called Bathymetry is being used to determine the amount of sediment deposited in the reservoir in a certain period of time. The comparison between the above methods can determine whether the rate of deposition matches the anticipated design time or not? Therefore, in this paper, deposition rate obtained through Bathymetry was compared to the amount of anticipated deposition at design time in Karaj and Latian dams. So we used 40 to 45 years of operation period, which is done by echo sounder system, with the gained results during designing of Karaj dam and Latian dam. Furthermore, sedimentation rate and volume reduction percentage are evaluated in these two dams and the results were analyzed for determining sedimentation rate and also to study whether the total sediment volume during the reservoir useful life coincides calculations during designing. In the end, it showed that the Area Increment Method for the mentioned dams was not an appropriate and adequate method to distribute sediments. The data obtained by sedimentation through Bathymetry findings can be a model for other dams in Iran and worldwide. © International Journal of Ground Sediment & Water, @ Sun Jichao. The website is https://ijgsw.eu.org/ http://ijgsw.net/