In this study we investigated biometric and morphometric traits of Capoeta buhsei in Gharachay River, Saveh. Sampling was in 5.90, 11.90 and 8.91. Sampling was by electroshoker. Samples after catching transferred to Azad university of Babols labratoar and investigated. Measurement of length was recorded by digital caliper to the nearest 0.01 mm and weight was recorded by digital balance to the nearest 0.01 g .Age determination was by observing scales in benicular loop with 40..Results of investigation of 53 male and 39 female of this species indicated that mean standard length of male and female was 131.46±23.59 mm and 152.96±25.07 mm respectively. Ratio of female to male was 0.73 :1 and with x2-test there wasn’t a meaningful relashionship between male and female ratio.

Estimating flood events sediment yield and its temporal variation are of the main and basic issues in watershed management strategies. On the other and there are little investigations about sediment yield behavior of the flood events and applicability of the sediment rating curves to estimate sediment load of flood events. In this study in order to investigate bias and errors of the sediment rating curves in estimating sediment load of the flood events, the estimated values of 10 types of rating curves compared by the observed values of some hourly monitored flood events in the Gharachay River of Markazi provinces. By considering accuracy and precision indexes the results shows that in all of treated sediment rating curves underestimated (40-80%) flood hydrograph sediment yield in this case the FAO’s method has relatively closer estimates to the observed data and despite of suitable applicability of the MVUE method in estimating annual sediment yield it could not prove to be applicable in the flood events cases.

Capoeta buhsei is native species in the Namak Lake basin and biological aspects of life history of this fish in Iranian waters is not very well known. Life history of this fish examined by collecting 92 samples in Gharachay River. Sampling done by using Electroshoker in July and January 2011 and October 2012. The maximum age was found +4 years in female. Sex Ratio (male: female) was 1: 0. 73, and length – weight relationship was BW=35. 55. TL3. 2 in male and BW=14. 8. TL3. 07 in female. Mean egg diameter (ED) was 0. 8726  0. 12 mm ranging from 0. 67 to 1. 1 mm. Mean absolute (AF) and relative fecundity (RF) were 4917. 2157 (  1690. 04 SE) egg female-1 and 69. 1 (  16. 15 SE) eggs g-1 body weight, respectively. AF and ED were found to increase significantly with increasing fish size, whereas RF increased significantly with both fish TL and weight.

A temporary model to assess desertification and providing the map of land susceptibility to the reducing processes of land efficiency was proffered by FAO and UNEP. The results of regional implementation of the FAO and UNEP method in Gharachay watershed are presented in this article. In this method, five major processes of land degradation were evaluated with two aspects including “current status” and “inherent risk”. For any of these aspects, the maps of low, moderate, severe, and very severe desertification were separated and the area of each class was calculated. Then, the maps of main processes affecting desertification were integrated together and two maps including “current status and inherent risk” were provided. Afterward, the maps of livestock pressure and human population were prepared. In order to obtain the total risk of desertification, the four mentioned maps were integrated and finally the risk of desertification classes were calculated. In view of the current desertification status in the studied region, the following results were obtained: The highest vegetation decline (76%) was observed in the east, south, and center of the region. The highest percentage of water and wind erosion (45.2%, 57.9%) was obtained in the south and east respectively; the highest soil salinization (34.7%) was observed in the east. In addition, the highest loss of groundwater resources was observed in the center and east of the region. The highest livestock pressure (58.3%) was recorded in the center of region; however, population pressure had little impact on environmental degradation.The area of each category, including low, moderate, severe, and very severe, was calculated to be 39.4, 27.9, 25.1, and 7.3 percent, respectively. Overall, according to the obtained results, the natural and human factors, particularly livestock pressure, were effective to create these conditions.

Climatic conditions have dried up since the late 5th millennium BC as if Paleoclimate research in the northern hemisphere, particularly Iran and neighboring countries, shows unfavorable climatic conditions and several periods of severe drought during 4th millennium BC. Also, based on environmental sedimentological studies on archaeological sites such as Mafin Abad of Islamshahr and Meymanat Abad of Robat Karim in Tehran province and Ghara Tepe of Qomroud in Qom province, it has been determined that all three sites were flooded by neighboring rivers in the mid and late 4th millennium BC. The occurrence of these floods coincided with the severe droughts in the 4th millennium BC. The enormous floods caused by severe centralized rains are, in principle, one of the main features of climate change and droughts. As the drought intensified, especially since the late-4th millennium BC, human populations in the cultural region of North Central Iran have decreased, leading to a cultural decline during the Bronze Age. This research tries to study the destructive impacts of climate change on ancient societies of the Tehran plain and the Qomroud-Gharachay basin, located in the western part of the North Central region of Iran. For this purpose, paleoclimate research of the Holocene Age and environmental sedimentological studies of ancient sites contemporary with Sialk III period have been used. Also, during environmental surveys of the Mafin Abad site, evidence of an ancient stream (possibly one of the branches of the Karaj River) belonging to the mid-4th millennium BC, was discovered. It is probable that the uprising of the same river destroyed the ancient village. The XRD analysis on the sediments of this river indicates the deliberate selection of this location for establishment of the important settlement in 5th and 4th millennium BC. According to the sedimentology, the ancient stream has been one of the most valuable mine of pottery clay in the whole of North Central Iran. Previously, there was one of the largest ceramic factories near Mafin Abad, which uses peripheral soil. Also, the existence of very fine and excellent pottery of Mafin Abad, belonging to the Cheshmeh Ali Culture with 3mm thickness is another reason to support this hypothesis. Thus, Mafin Abad has great environmental potential for attracting human communities, but has failed to reach the threshold of urbanization. Mafin Abad and Ghara Tepe in the mid-4th millennium BC and Meymant Abad in the late-4th millennium BC ended their lives. Although it is not yet known exactly where the Meymanat Abad settlement was formed after the Mafin Abad collapse, but because the most recent Mafin Abad cultural material belongs to the early Sialk III phase and the oldest Meymanat Abad cultural material belongs to the same period, it is likely that after the end of Mafin Abad due to the flooding of the ancient stream which was a branch of the Karaj River, Meymanat Abad has been established. Since the absolute dating of Meymanat Abad indicates the oldest settlement at around 3700 BC, it may be possible to attribute this date time to the flood in Mafin Abad. As noted, most of the paleoclimate researches confirm the occurrence of a climate change and drought in about 3700-3500 BC. Also, the eventual collapse of Meymanat Abad in the late 4th millennium BC overlaps with the 5. 2 ka BP drought event (3200 BC) that continued until the early 3rd millennium BC. Since then, the long cultural decline began in the North Central Iran region and covered the whole Bronze Age. Perhaps one of the most important reasons for the significant decreased of settlements and the existence of only one to two layers of settlement after the Sialk III period was severe climate change. These natural hazards have undoubtedly had profound impacts on the subsistence system of the North Central societies of Iran.

Instantaneous unit sediment graph (IUSG) is one of the methods for predicting sediment graph of the flood events and its application needs to estimation of storage coefficient (Ks), dimensionless shape factor (ns), time to peak (tp) and instantaneous sediment supply. Investigation of relationships among the mentioned parameters and rainfall and water discharge characteristics could facilitates use of IUSG in ungaged drainage basins. In this research concurrent flow and sediment discharge of five flood events in Poledouab hydrometric station monitored hourly .IUSG parameters calculated using observed sediment graphs and rainfall hyetographs and their relationship investigated with excess rainfall and peak water discharge of flood events. The results show that correlation coefficient (r2) of power regression equation between Ks and rainfall excess is greater than peak flow (0.79 and 0.42).dimensionless shape factor of ns shows statistically weak relationship with rainfall excess and peak flow but its ratio to time to peak of sediment graph (ns/tp) resulted in statistically meaningful relationship with the rainfall excess and peak flow (respectively 0.85 and 0.67 of r2).application of the obtained equations in this research for predicting sediment graph of some flood hydrographs and comparing the results with the sediment rating curve methods show that rising limb of the sediment graph could be predicted more accurately than falling limb of sediment graph.

Flood is a natural phenomenon that inflicts damages and casualties throughout the world every year. For flood hazard zonation and determining the lands on the bank of the Gharachay River, located in the Ramian watershed, that may face flooding, a section of the river with a length of 8.5 km was selected. This length was divided into subsections with respect to morphological and hydraulogical characteristics, and 41 cross sections were chosen. Then, the Cowen method was adopted as the best method to determine the Manning's coefficient. In the next step, flow characteristics and geometrical specifications and the Manning coefficient for each cross section were inputted into the HEC-RAS software program and the water level profile for each return period was computed. Then, the AutoCad software program was employed to draw the flooding hazard zones and determine the flooding area and average depth of floods for all cross sections in various return periods. After determining the average area and depth of flood for hazardous areas, and by using flood damages functions, the amounts of damages in urban and agricultural regions were determined separately. Results of the research show that the amount of damages up to the 50-year return has a mild increasing trend, but after that the rate of damage increases sharply. Therefore, the 50-year return period has been interpreted to be the critical return period for this area.

Identifying and determining the flood potential and prioritizing of the flood discharge in the sub-basins is very important in terms of watershed management, flood control and watershed management projects. In many watersheds, it is difficult to investigate and determine the impact of each of the factors and even upstream sub-basins on creating an outlet flood, especially in the sub-basins without hydrometric station. The purpose of this study was to investigate the effective parameters in the occurrence of flood in the sub-basins of Koshkabad watershed and compare the two methods of Factor analysis and rational method for flood priority. Koshkabad Basin is located in the central part of the Hamedan province and hydrologically is the main part of the Gharachay basin that it flows into the Qom lake. In this study, to determine the potential of flood sub-basins and their prioritization, First, extracted of climatic and physiographic features in sub-basins, then provided flood potential map in the sub-basins using factor analysis method. Also, using the Rational method for estimating run off coefficient, flood intensity in the sub-basins was determined by considering the effective factors in the runoff coefficient of the area including slope, landuse and soil condition and were prepared Potential map and prioritization of flood sub-basins. Comparison results of the two methods shows that the potential map of the factor analysis method is very identical to the map of the flood potential map in the Rationnal method. The final results of prioritization in both methods indicated that the Abaro, Yelfan, Mary anadg and Dareh Moradbik sub-basins with Severe and very heavy flood Are in the first to fourth priority and Siakamar, Qaraachy and Koshkabad sub-basins with a relatively low to low flood intensity are in priority from eighth to tenth priority.