Diatoms are the division of Bacillariophyceae. Epilithones are the group of diatoms which live on the stones and hard surface. This study concerned the identification and populational change of diatoms flora of Jajrood river .This study is based on the observations collected from 6 stations during a period of time from Jun 2004 to May 2005 at 30 days intervals. pH, dissolved oxygen levels, electrical conductivity and temperature were recorded during this study. Samples were prepared using Patrick & Reimer procedure.In total 51 species from 17 genus of diatoms identified. Cymbella Kutz., Navicula Grnn., Diatoma Ehr., Cocconeis Ehr., Gomphonema Kutz. and Nitzschia Hantz were abundant. Diatoms diversity decreased from upstream toward downstreams can be inferred as an indicator for the increasing of water pollution and its impacts on the diatoms species richness and also their population size at this part of the river.

Extended Abstract Introduction River terraces represent a history of river stratigraphy and provide valuable information for understanding the interactions of tectonics, erosion, and climate change. The high altitude of the Jajrood basin has resulted in extensive glacial remnants, especially the accumulation of moraines upstream of the basin. The extent of moraine depositions under the upstream basins of the Jajrood River is not evident in the structure of river terraces and they do not have a uniform elevation. Moreover, the relations of old glacial conditions in the sedimentary interference of terraces cannot be easily reconstructed and discriminated, and there is no regular order in the stratigraphic sequence and sedimentological conditions of the river terraces. The moraine deposition seemingly has had a major role in the differences in river terrace sequences from upstream to downstream of the study area, which calls for further investigation and is also addressed in this study. Many studies have delved into the analysis of the evolution of the river terraces. Other important areas of study include paleontology and sedimentology and their effects on the canal sustainability against flow dynamics. This study aimed to explore the climatic and neo-tectonic developments of the Jajrood River Basin and the role they have played in creating terrace sequences.   Materials and methods This pure research investigated the role of neo-tectonic developments and climate change on the formation and evolution of terraces in the Jajrood River Basin. The research was based on analytical calculations and reports prepared through surveys as well as remote sensing methods to examine the effects of tectonics in the area. In addition, sedimentological evidence was studied to see how climate change has affected the formation and evolution of these terraces. The primary research tools were topographic and geological maps alongside aerial photographs and satellite images. Other fieldworks such as terrace morphometry using GPS measurements and sedimentological analysis helped to add insight to the findings. Then, the data was analyzed in ArcGIS. Here, the Jajrood Canyon was divided into three sections to better examine the morphogenesis of the terraces. Next, the transverse profiles and stratigraphic sections were drawn up to investigate the sedimentary strata in each section through morphometry, and then the evolution of the terraces was analyzed and reconstructed. The tectonics were studied using radar images to determine vertical displacement through the small baseline subset (SBAS) time series. Here, 27 Sentinel-1 images were used for the period from Oct. 14, 2014, to Oct. 27, 2016. which was performed using Generic Mapping Tools (GMT) in Linux OS. After preparing the interferogram maps, a map of the displacement in the study area was generated using the SBAS method (Zhao, 2013). Moreover, changes in the climate were studied using sedimentological and stratigraphic evidence.   Result and discussion The research findings can be classified into two parts. First, neo-tectonics was investigated through remote sensing methods and the analysis of vertical displacement across the region. Then, the effects of these neo-tectonic processes on the genesis and evolution of terraces were examined. In the second part, the effect of climate change on terrace developments was explored using sedimentological and stratigraphic evidence.  In the first part, the region's tectonics was analyzed using radar imagery. In doing so, the vertical displacement was measured using SBAS time series and 27 Sentinel-1 imagery during the period from Oct. 14, 2014, to Oct. 27, 2016. The specifications of the research images are presented in Table 1. The images were selected based on the research purpose and the baseline of the images relative to each other. The VV polarization was used for all images since co-polarizations exhibit a stronger backscatter. Some sensors have different polarizations, and images with different polarizations can inform interpretations to a great extent. After preparing the images, for measuring displacement using the SBAS method, first, the temporal and spatial baseline of the images was examined and image pairs were selected for interferogram generation (Table 2 and Figure 3), which was performed using Generic Mapping Tools (GMT) in Linux OS. After preparing the interferogram maps, a map of the displacement in the study area was generated using the SBAS method. In the end, the role of morphotectonic relations in the morphogenesis (i.e., origin and development) of the terraces were examined.   Conclusion These findings suggest that terraces in the Jajrood Canyon are highly heterogeneous in terms of sedimentological structures, stratigraphy, and altitude. For instance, the T3 to T1 terraces, respectively, were located 130, 90, and 80 m above the river. These terraces have also experienced three intermittent processes. These three river terraces were created through the combined effects of climate change, tectonic uplifts, and the formation of dam lakes. The results of SAR interferometry (InSAR) and fieldworks also confirm the effect of active tectonic uplift differences along the main canal. These differences reflect the differences in their morphogenetic processes. The altitude of the terraces at the Oushan River tributary (Section 1) is nearly 130 meters. However, this section's altitude downstream (near Hajiabad Village) is estimated at 90 m. This difference cannot be merely due to baseline discrepancies. Evidence indicates that a sedimentary interference originating in the lake due to a past landslide downstream of the study area (Hajiabad landslide) is the cause of the higher altitude of the terraces in this section. The terrace sequences were not the same in any of the three sections. To be more precise, there are three identifiable terrace levels in Section 1, two in Section 2, and one in Section 3. In addition to the differences in the tectonic baseline, three factors—namely climate change, moraine, and the formation of a landslide-dam lake downstream—were identified for the genetic diversity, sequence differences, and terrace sequences throughout the three sections. In addition to morphometric differences, there were great differences in the genesis of the terrace sediments. The river has contributed the most to the formation and structure of terraces and their genesis. Nevertheless, the interference of landslide-dam lake deposits, moraines, and alluvial deposits, consecutively or simultaneously, have affected particularly sections 1 and 2 through differences in flow dynamics. Meanwhile, greater uniformity can be seen upstream, particularly in the Garmābdar basin (Section 3), such that upstream terraces in this section are predominantly glacial.

The Jajrood River originates from the Alborz Mountains north of Tehran, mounts Shemshak and Johnson, and flows towards southwest. After joining the Garmabdar and the Routeh rivers, it turns towards southeast and when joining the Big and the Small Lavasanat rivers, it pours in Latyan Dam. About 295 mm 3/y of the water of Latyan Dam is sent to Tehran's 4th water treatment plant in Tehranpars. The rest is released as riparian right for agricultural uses in Varamin Plain. The Jajrood River serves many villages on the trans-passing course and receives their entire wastewater because the region’s hills, the lack of facilities for wastewater treatment, and the problem of solid waste disposal on the river banks.The Jajrood River supplies the drinking water of about 2,600,000 people in the east of Tehran through Latyan Dam. That is why the management of its water quality seems to have a very high priority.During a period of 6 months in 2004, samples were taken from 18 villages before the water flowed in and after it flowed out of them. Then, the important factors of water quality of the samples were compared with those of the previous years and the standards. Changes in the amounts of certain parameters such as BOD, COD, and TDS were easily observed after the river passed through every village. Tests proved that the water would get polluted after passing through villages. It became clear that the sources of pollution were domestic sewage and leakages from fruit gardens as well as partially domestic solid wastes dumped into river banks. In the end, offensive and defensive methods of water quality management are recommended.

Flood is natural phenomena. That human social accept it, is inevitable. But the reason of occurrence, size, and repetition is multifactor that change condition region of climatology, natural and geographical. Obviously the reason of flood is precipitation. But studies show there is not liner relation with this factor. As such disruptive this relation in additional to geographical condition has physical properties of basin and is properties of hydrologic. The case study of this research is located northeast of Tehran. It located in the east longitude from 51o 22’ to 51o 52’ and north latitude from 35o 45to36, 50. In this research for modeling of flood flow of Jajrod river basin first effective indexes in flooding with use of experience past study and special traits of basin recognized that superlative indicator effective in flooding region has been characterized and proportion of each sub basin was characterized. Ultimately, with the use of multiple regression method (enter method) the flooding model of basin was produced. Required layer for evolution with use of GIS software was produced. Conclusion of research shows in physiographic properties of studied, invoices of ratio of figure, ratio of density, time concentration, basin surrounding, sum of length of river, length of first class River modeling of flooding has maximum importance.

Diatoms are major constituents of algal flora in aquatic ecosystem. This study was conducted in the 140-km Jajrood Rriver from April 2004 through May 2005. Samples were taken on monthly intervals from six stations. Physical parameters such as DO and EC were measured in situ and chemical parameters such as BOD and COD were measured in the laboratory. Samples of Epilithic diatoms were taken using a core device DI 25 cm2 , of Epipelic diatoms using a core device DI 16 cm2 , and of Epiphytic diatoms by cutting small portions of Microspora and Cladophora. For better observation, cell walls and permanent mounts were prepared using Patricke and Reimer procedure. In this study, 92 species belonging to 21 genera of diatomses were identified. A wide diversity of species was observed in Cymbella, Diatoma, Navicula and Cocconeis.

The Eurasian otter (Lutra lutra) is a semi-aquatic mammal from Mustelidae family. It is recognized as one of the top predators in freshwater systems, and thus has the potential to play an important role in the functioning of these systems. There are only 2 otter species in Iran. Information about this species in Iran is absent. River ecosystems are one of the important habitats for otters. Jajrood River with 140 km length in the east of Tehran is one of these habitats that were selected for this study. To study otter distribution standard method was used. This method is a systematic sample survey for field signs of otters.16 survey sites at about 5 km intervals were selected and Otter signs, habitat parameters such as vegetation cover, river width and fish of river were recorded for each 600m stretch by walking the entire it (both banks) of all rivers, wading in the river wherever possible. A total of 599 signs (spraints, tracks, holst, rolling places and passes) were identified over the whole study period, the most common being spraints. Otter spraints were found in 6 of the sites of river Surveyed and in the study area, three core areas could be identified.

Jajrood is a permanent stream with physical and chemical properties appropriate for cold water fishes. Significant populations of different species of fish were identified in the stream (Refer to table 1 for scientific names). Members of Salmonidae and Cyprinidae (Particularly Capoeta sp.) constituted the important fish fauna.Permanent now of water, different agricultural fields around, diversity of trees and shrubs along the river together with an abundance of insects provide an excellent habitat for bird funa. About 80 species of birds were identified in dependence with the river. Some bird species are aquatic, some depending on the margins of the river while others live on trees and shrubs.Fifteen species of mammals are living along the river. Some, such as otter (Lutra lutra) are completely dependent upon water, while some such as wild bard Jackals, although terrestrial, but are ecologically dependent on the aquatic environment.Amphibians possess the lowest number of species. Population abundance of two species, Rana ridibunda and bufo viridis, depends on local conditions. Aquatic vegetation of the river system were collected and I identified (label 4).

The aim of this study was to investigate Trichoptera (arthropod) fauna in the Jajroud River. For this purpose, Trichoptera were collected from three stations (Hajiabad, Saeedabad and Khojir) in Jajroud River and were identified in terms of morphology and taxonomy using identification keys to the level of genus and species. Based on the results, four species of Macrostemum hestia, M. fenesrtratum, M. dohrni and Hydropsyche dolosa from the family Hydropsychidae were identified, which is the first reported in Iran and this river. The frequency of Trichopters in the study areas was very low in the winter months and was highest in June, July and August and then decreased.

Jajrood River and its drainage basin are of utmost importance to Tehran. Samplings were carried out to determine factors affecting water quality and the changes in those factors. Fish culture ponds and the sewage produced by them are one of the most important sources of water contamination in the river. Chemical tests were also conducted in four stations.Considering flow of the river and its morphology, the results show that DO, BOD, COD, NO3, NO2, PH, NH3 and PO4 are in the standard range but the amount of Coliform bacteria in all stations are more than the standard limits.

Crustaceans are ecologically important, because of their effective role in food web and community structure of ecosystems. Taxonomic identity of fresh water crabs has been studied in Iran representing Potamidae family as dominant fluvial crabs (Khatami, 2001). Khatami (2001) also recorded an unknown oligochaete in the mantle cavity of fresh water crab “Potamon persicum”. The present study further separated and identified an oligochaete from Potamon persicum in Jajrood River, east of Tehran, Iran.