فهرست مطالب ghorban ali khoda bakhshi

In the last century, dams have constructed with the objective of water supplies for agriculture, drinking water and industry. However, the results from the performance review of dams show adverse effects on the downstream environment and the availability of water resources. The purpose of the Chashm dam construction on the TalarRiver's tributaries is the water supply for Semnan city.
This study was conducted in TalarRiver watershed. TalarRiveroriginatesfrom AlborzMountains in Mazandaran province, in the southern Caspian Sea basin, in north of Iran and flows parallel with the Firouzkooh-Ghaemshahr road and it arrives to the Caspian beach area in the Malek Kala village. In order to supply the water requirements of Semnan city, the construction of Chashm dam on the TalarRiver's tributaries placed on the agenda of the Ministry of Energy. However, because of the uncontrolled exploitation of agricultural streams and invasion of privacy riverbed, the TalarRiver has acute and critical conditions from the point of hydrologic and environmental. To study the hydrological impacts of Chashm dam, Talar watershed was considered with an area of approximately 1057 square kilometers of the Pole Sefid gauging station using a rainfall-runoff model.
Simulation of the study area hydrological behavior shows that the Chashm Dam average water discharge is near to 8.6 million m3. This figure will be significant changes during wet and droughtperiods. The minimum and maximum monthly discharge of the Chashm Dam watershed in August and February is equal to 0.31 and 0.55 m3/s respectively. The minimum and maximum monthly water demand in turn in October and August is equal to 0.015 and 0.4 m3/s respectively and this shows that the river discharge in June is lower than the downstream water demand. Based on confirmed studies of the Kamandab Consulting Engineers, drinking water requirement of Semnan province, water rights user's requirement and downstream environmental requirements are 4.54, 2.164 and 2.448 million m3, respectively. This is despite the fact that the volume of annual input water is slightly lower than this figure in normal.
Simulation of the study area hydrological behavior shows that the Chashm Dam average water discharge is near to 8.6 million m3. This figure will be significant changes during wet and drought periods. The minimum and maximum monthly discharge of the Chashm Dam watershed in August and February is equal to 0.31 and 0.55 m3/s respectively. The minimum and maximum monthly water demand in turn in October and August is equal to 0.015 and 0.4 m3/s respectively, and this shows that the river discharge in June is lower than the downstream water demand. Based on confirmed studies of the Kamandab Consulting Engineers, drinking water requirement of Semnan province, water rights user's requirement and downstream environmental requirements are 4.54, 2.164 and 2.448 million m3, respectively. This is despite the fact that the volume of annual input water is slightly lower than this figure in normal. In addition, the Chashm Dam area is about 110 hectares and given the minimum annual actual evaporation equal to 700 mm, about seven hundred thousand cubic meters of water stored in the reservoir will be lost. Due to the simultaneous occurrence of the maximum water requirement, maximum evaporation and a minimum of water inlet to the Chashm Dam reservoir in warm seasons, it seemsthat, it is not possible to provide needs based on these studies and no doubt, in the case of water supply in Semnan province, we have to stop the flow of the river in downstream of the dam. The results of this study suggest that on many rivers large headwater dams have reduced the frequency and duration of floodplain inundation downstream and these changes lead to changes in downstream ecosystems. The results from the simulation and analysis of the Chashm Dam in downstream are as follows: a) stop of the river flow in downstream of the dam site, b) the sharp decline in river discharge in minimum (varied) flows, c) reduce in the rate and volume of maximum flows, d) changes in the hydrological regime of the river such as base flow, flow stop, the frequency of the river full section and competency which will make dramatic changes in the morphology of the river and downstream ecosystems. Note that is not verified by modeling and forecasting studies, is how to manage the reservoir. The amount of water stored in the reservoir and discharge to downstream is directly a function of the reservoir management.

Several hundred pesticides of different chemical compositions are currently used for agricultural and vector control purposes all over the world. Because of their extensive use, they are detected in various environmental matrices, such as soil, water, and air. Due to their lipophilic nature, hydrophobicity, and low chemical and biological degradation rates, organochlorine pesticides (OCPs) have led to their accumulation in the biological tissues and subsequent magnification of concentrations in the organisms due to the progress up the food chain. The organochlorine pesticides group includes DDT (dichlorodiphenyl trichloroethane), methoxychlor, aldrin, dieldrin, chlordane, toxaphene, endrin, heptachlor, and lindane (gamma isomer of benzene hexachloride (BHC)). These are trade names for closely related hydrocarbon compounds to which several chlorine atoms have been joined. Residues of OCPs were detected in almost all environmental compartments, including water bodies, food, fish, and milk as well as in human beings. In this study, the residue levels of 20 organochlorine pesticides (OCPs) were found in the river water samples obtained from the different regions of Mazandaran province, Iran. Total water samples, from 6 sampling sites, were collected every two months between 2010 and 2011. For this study, a total of 56 water samples from 6 sampling sites were collected. All the water samples were collected in high purity glass bottles and immediately transported to the laboratory. After this, the samples were stored at +4°C and extraction of the OCPs was performed within 48 h. Some instruments were used for this experiment. 5.0 mL LiChrolut® EN cartridges were purchased from Merk, Germany. The vacuum assembly was homemade and the vacuum was generated by the homemade vacuum pump. The analysis of the reported OCPs after extraction was carried out by gas chromatography. Gas chromatograph used was of Agilent GC 6890 N with an electron capture detector (GC-ECD). The column used was HP-5 (30 m x 0.32 mm, IP 0.25 µm) and obtained from Sigma Chemical Co., USA. Solid Phase Extraction (SPE) methodology was developed by spiking of 1.0 mL of organochlorine pesticides mixture of 1.0 mg/mL concentration each (in methanol-water) in 499.0 mL tap water. This mixture was shaken for about 30 minutes. The spiked water sample was kept at room temperature overnight. C18 Cartridge was pre-conditioned by using methanol (10.0 mL) followed by water (10.0 mL). After equilibrium, 0.5 L of the spiked water was passed through this cartridge at 10.0 mL/min flow rates. The elution of OCPs was carried out by using ethyleacetate at different flow rates 1.0 mL/min. This methodology was applied to the natural conditions by replacing spiked water by Telar and Tajan rivers water and the results were compared. The developed SPE and GC methodologies were applied for the analysis of organochlorine pesticides in the Telar and Tajan rivers. For this purpose, river water samples were collected from the Telar and Tajan rivers at 6 different sites. The values of concentration of the organochlorine pesticides observed are given in Table 1. The developed SPE and GC methods were used for the separation, identification, and quantification of organochlorine pesticides in the water of Telar and Tajan rivers. The reported values of pesticides in the Telar and Tajan rivers water indicates that the rivers arent polluted. Besides, these methodologies are rapid, selective and reproducible. The percentage extractions of organochlorine pesticides are quite good. Therefore, these methods can be used for the analysis of organochlorine pesticides in waste, surface, ground and mineral water samples.