Probability of earthquake hazard | Distance to fault lines | Relative area | |||
Active Faults | Passive Faults | Active Faults | Passive Faults | ||
Very low risk | 0-20 | 60-76 | 32-42 | 7.29 | 1.42 |
Low risk | 20-40 | 45-60 | 24-32 | 13.82 | 3.96 |
Medium risk | 40-60 | 30-45 | 16-24 | 16.66 | 8.13 |
High risk | 60-80 | 15-30 | 8-16 | 21.51 | 22.04 |
Very high risk | 80-100 | 0-15 | 0-8 | 40.72 | 64.45 |
sum | - | 100 |
Probability of earthquake hazard | urban Settlement | Population (2011) | Relative population frequency (percent) | ||||
Active Faults | Passive Faults | Active Faults | Passive Faults | Active Faults | Passive Faults | ||
Very low risk | 0-20 | 3 | 1 | 135846 | 17106 | 1.14 | 9.07 |
Low risk | 20-40 | 6 | 4 | 86133 | 144021 | 9.62 | 5.75 |
Medium risk | 40-60 | 10 | 8 | 739095 | 754968 | 50.43 | 49.37 |
High risk | 60-80 | 14 | 18 | 380908 | 273137 | 18.24 | 25.44 |
Very high risk | 80-100 | 18 | 20 | 155188 | 307938 | 20.57 | 10.37 |
sum | 51 | 1497170 | 100 |
Probability of earthquake hazard | Rural Settlement | Population (2011) | Relative population frequency (percent) | ||||
Active Faults | Passive Faults | Active Faults | Passive Faults | Active Faults | Passive Faults | ||
Very low risk | 0-20 | 162 | 42 | 54240 | 30236 | 5.51 | 3.07 |
Low risk | 20-40 | 379 | 147 | 183718 | 92018 | 18.68 | 9.35 |
Medium risk | 40-60 | 481 | 291 | 255412 | 176183 | 25.96 | 17.91 |
High risk | 60-80 | 553 | 766 | 245392 | 340448 | 24.95 | 34.61 |
Very high risk | 80-100 | 1350 | 1679 | 244942 | 344819 | 24.90 | 35.05 |
sum | 2925 | 983704 | 100 |
The correct management in natural ecosystems is not possible without knowledge of the health in its sectors. Vegetation is the most significant sector in ecosystem that has important role in its health. Resilience is one of the defining features of health vegetation The term resilience was first introduced in the study of ecological systems and demonstrates the ability of the ecosystem to maintain its performance in the face of environmental disorders. A resilience-based system is not only equipped with a disorder adjustment mechanism but also has the potential to benefit from changes in a way that lead to creating an opportunity for development, innovation, and updating. Therefore, when a change occurs, the resilience provides the needed conditions for restarting and reorganization. If this goes beyond disturbing forces, the system will have the power to return to the maximum vegetation density with the least erosion effects, otherwise the system will be vulnerable to the change that was created and could already be controlled.
This research was done in part of North east of South Khorasan province (arid climate) with the aim of quantifying vegetative resilience on behalf of ecosystem health in response to drought occurrences and long-term precipitation changes, as environmental disturbances. Therefore first, using daily precipitation data from 15 meteorological stations around the study area, their annual precipitation was extracted and was standardized by Standard Precipitation Index (SPI) over the course of thirty years (1986 - 2015). Then, the SPI index data in 15 stations were interpolated by ArcGIS software based on Inverse Distance Weighted (IDW) method and dry, wet and normal years was estimated in the study region for each year. On the other hand, from archive of satellite images of Landsat 5 and Landsat 7, an image was created for each year in study period, between 15 June and 15 July, with permanent coverage at the best of growth. Following the necessary corrections for satellite images, the average Transformed Normalized Difference Vegetation Index (TNDVI) was obtained of each image by ENVI software. Finally, effected of precipitation changes on mean TNDVI was assessed and vegetation resilience was stabilized whit selected of sever time period samples based on four effective parameters (Amplitude, Malleability, Damping and Hysteresis).
Comparison of annual precipitation variations in the thirty-year time series (1986 -2015) indicated two approximate wet and dry periods in study area. The wet period is related to the first fourteen years of the time series (1986-1999) and the dry period is related to the last sixteen years (2000-2015). In this term, severe precipitation incidents with different intensities were occurred in the study area including one case of very intense precipitation (1986), one case of intense precipitation (1991) and two cases of moderate precipitation (1996 and 1992). Also, four drought incidents were occurred including one case of intense drought (2001) and three cases of moderate drought (1987, 2006 and 2008). All precipitations (wet years) are related to the first half and most droughts are related to the second half of the studied period. In this study for fixing of vegetation resilience in study area and for calculating of its parameters, In addition to the thirty-year time series selected sever time sections. in the whole study series (1986 - 2015), maximum of mean TNDVI (49.37 %) was in 1986 (reference), the lowest mean TNDVI (43.58%) was in 2010, The year effect of the decrease precipitation and drought, and mean TNDVI in 2015 was 44.28 %. Amount of parameters amplitude, malleability and damping are respectively 5.79, 0.7 and 5.09, and hysteresis was zero (%). The result of this case showed that the vegetation has moved towards the reference state (Resilience) but has not reached to amount of reference vegetation. The most specific cases for vegetation resilience happened from 1986 to 1996 (wet period) and 2003- 2009 time sector (dry period). In the first time section amount of amplitude and malleability were 0.64 %, damping was zero and hysteresis was 0.25%. The result of this case showed that not only the vegetation was returned to the reference state but also was increased to the reference (Cross reference).So despite the reduced rainfall and occurrence of sever occurrences of drought in dry period, hysteresis parameter (0.05 %) observed in 2003- 2009 time sector too that confirmed clearly vegetation health in study area whit dry climate.
Awareness of the health status of the vegetation and its response to long-term precipitation changes and environmental disorders, such as drought occurrence, ensure the success of the managerial plans for renewable natural resources. The present study is the second study on quantifying the vegetation resilience and the first study under dry climatic conditions in Asia (an average annual precipitation of 160 mm) conducted in Iran by calculating four factors related to resilience, and is the first study that has presented the factor hysteresis in the calculations. Despite continuous of difficult condition, the native vegetation of the study area has been able to return the reference state not only by resolving the disorder relatively, but also it has experienced hysteresis stage. A set of quantitative calculations showed despite reduced annual precipitation and drought events, vegetation has been able to maintain its resilience, which indicates the health of the vegetation in the studied ecosystem. With the presence of such amazing protective and consistent mechanisms in the vegetation of arid regions, it is possible to maintain and restore these regions by proper managerial plans.
Quantitative assessment of landslide sedimentation in the ILAM dam Basin
Information on the accurate volume of landslides and sedimentation in landslides is a research necessity, with the assumption that the bulk of sediment accumulated in the ILAM Dam (located between , E and , N) is related to the surface landslides of the basin. Although the role of landslides in erosion, sediment transport and sedimentation of slippery basins is confirmed and different experts understand and determine the relationship between the fluctuation of slopes and the fluctuation system in many respects more important than other areas. Because according to the results they can assess the widespread environmental changes, but comprehensive research on the scale of catchment basins has done very little (Harvey 2002). So far, the study of wet landscapes in Iran has been more sensitive to the factors, their sensitivity and their hazards, and there has been no study on the sedimentation of landslides.
Data and Method
First, using a geomorphologic system methodology with topographic maps of 1: 50000, geological map of 1: 100000, aerial photography1: 20000, Landsat TM1988 ETM2002,2013 satellite imagery, and Google Earth in the GIS environment in the following sub-basins and landslide events at the following levels The basin was drawn. The discharge data of the water and sediment flow of three hydrometric stations GOLGOL,CHAVIZ and MALEKSHAHI Station were provided from the waters of the ILAM province. Two models of estimated MPSIAC and EPM models have been used to estimate soil erosion and subsoil sedimentation. The Moran spatial correlation model was used to introduce the spatial pattern of landslides, and the fuzzy logic model was used to determine the relationship between the dependent landslide to the independent variables and the potential risk of landslide hazard in the basin. In order to elucidate the quantitative results of landslide sedimentation, empirical models of estimation of sediment erosion, hydrological model of discharge curve and sediment, observational statistics of sediment during statistical period, landfall time occurrence in compliance with the hydrometric station sediment peak during the statistical period of computation Estimated a small amount of sedimentation of the landslides of the ILAM dam basin.
Result and Discussion
The spatial correlation model of Moran showed that the data have spatial correlation and cluster pattern. The average total sediment production in the MPSIAC model in the GOLGOL basin was estimated to be 13.3 tons per hectare per year under the CHAVIZ basin of 10.3 tons per hectare for one year and 4.00 tons per hectare in the sub-basin MALEKSHAHI. Using hydrological model of discharge-sediment curve, the mean sediment was calculated during the statistical period at the hydrometric station of the sub-basin of GOLGOL 18.8 ton per hectare, the station CHAVIZ 10.4 tons and the station MALEKSHAHI 0.9 tons of sediment per hectare per year was calculated. According to the results of the research methodology, the observation of the sediment in the two stations of GOLGOL and CHAVIZ compared to estimated sediment is related to the events occurring in these two sub-basins.
The data of 16 active landslides were recorded. Under the GOLGOL basin, 9 landslide events occurred, and in the CHAVIZ basin, 7 landslide events, the time of landfall occurrence recorded with sedimentary peaks, the length of the statistical period, the precipitate in the sub-basins was almost synchronized. Average relationship between suspended period of the statistical period - average of the peak delayed flight time of the statistical period coinciding with the occurrence of landslide = the amount of suspended load of landfall occurrence in the basin.
The amount of suspended land slip under the GOLGOL 75088.19 - 315.85=74772.34
Landing slope under the Chavez Basin 19907.30 - 20.24=19887
The area of the sub-basin is about 29,000 hectares and the active landslide area is about 100 hectares. According to the calculations, 77772.34 tons of suspended sediment is a sedimentary passage passing at the GOLGOL hydrometric station, which shows with a coefficient of 1.4 times the suspended sediment load of approximately 104681 tons of landslide sedimentation in this sub-basin, which shows the amount of sediment yield 100 hectares of landslide, so each landslide hectare had an average of 1046. 81 tons of sediment deposited at the GOLGOL hydrometric station. The area under the Chavez Basin is about 14000 hectares and the active landslide area of this sub-basin is about 65 hectares. According to the data of the discharge data, the sedimentation of the Chavez hydrometric station is 19887 tons of suspended sediment load, which shows a 1.4 equivalent of 27842 tons of landslide sedimentation in this sub-basin, equivalent to a slope of 428.33 tons per hectare.
Conclusion
According to the calculations, it is concluded that in the sub-basin of flowering GOLGOL, 37.35% is equivalent to 4.9 tons per hectare per year, the increase of sediment is related to landslide events. As a result, 28.2 tons of sediment per hectare were introduced in one year Dam reaches ILAM. The results showed that in the CHAVIZ sub basin, 38.2 percent is equivalent to 4.6 tons per hectare per year for the increase of sediment related to landslide events. As a result, an amount of 14.5 tons of sediment per hectare has entered ILAM dam in one year. In the sub-basin MALEKSHAHI, there was no increase in sediment during the period without active landslide occurrence. A total of 1237314 tons of landslide deposition have entered the ILAM Dam. To control this threat, the appropriate action by the executive office for sustainable development should be applied.
In Iran, there is a general risk of runoff and flood, and since this country has a dry to semi-arid climate, its predominant rainfall is not evenly distributed in terms of time and place. Routine runoff at the earth's surface can lead to risks such as groundwater abatement, social issues such as population migration, erosion and loss of soil fertility, sedimentation in reservoirs and water quality in rivers. Also, damage to the agricultural sector, subsidence, the destruction of residential buildings and the reconciliation of the urban, rural and nomadic order are all examples of controversy about the risks that runoff and flooding are due to. The severity of these hazards in the Afje watershed is due to the geographical location, the specific climate, geology and pond factors, and a large volume of flooding every year causes the destruction of residential areas, agricultural lands and many financial and financial losses.
In this research, data collection was carried out through library and field resources. The main tools of this research were topographic map of 1: 25000 which was used by GIS software for the separation of layers and determining the boundaries of the basin; Land use maps and user data and hydrologic groups of the study area were also used to estimate runoff height using curve number method and Arc-CN Runoff instrument. Then Arc-CN Runoff tool was used to prepare layers and curve number map (CN). Finally, the runoff height of the studied basin was prepared in the GIS software.
Soil Hydrology Group: According to the studies, in terms of breadth and extent, the Hydrologic Groups C has the largest area with relatively high runoff potential. By matching the map of Hydrologic Soil Groups and the mineralogical units of the basin it can be stated that the green mass tuff and thick conglomerates are in the hydrologic group D, and the thick layers of green tuff, marl and sandstone in the hydrologic group C and the rocky layer of limestone in The hydrological group B is located.
Land use: The hydrological status of the land and types of uses in the Afje watershed basin are as follows. Most of the catchment area is covered by medium-sized meadows, which comprises 53.77% of the basin area and is located in the hydrological group C with relatively high potential of runoff production. The rock outcrops are in the next rank, which is in the hydrological group D.
Runoff curve number (CN): Land use maps and soil hydrologic groups were combined and extracted for each curve number range (CN) and CN map was prepared. The Afjeh basin has a curtain number of 66 to 100. The highest value of the curve number is 100, which is related to the outflow of the Afjeh watershed basin, which is practically inert, so all precipitation becomes runoff. The Afjeh basin has a curtain number of 66 to 100. The highest value of the curve number is 100, which is related to the outflow of the Afjeh watershed basin, which is practically Impervious, so all precipitation becomes a runoff. In fact, the curve number 100 in stone is 5.59 square kilometers from the area of the Afjeh watershed. But gardens and Agricultural land have the lowest CN (curve numbers 66 to 77) in the Afjeh basin, and include 4.53 square kilometers of basin area. Therefore, the lower parts have a lower CN than the upstream of basin.
The runoff height in the four seasons was calculated based on the daily precipitation values occurring at mentioned times.
Based on the average daily rainfall of spring with a value of 10.79 mm and runoff classification, in a small part of the gardens in catchment area due to high permeability of the soil, 2.54 mm of precipitation has become runoff, although it is due to stone due to The Impervious of the surface, 10.66 mm of precipitation, turned into runoff.
According to the studies carried out and according to the potential maps of runoff production in the Afje watershed, in the garden with the value of the curve number 66 and daily precipitation (for example, in the winter with a rainfall of 4.04 mm), the runoff height is 0.76 mm And the peak of discharge of 0.47 cubic meters per second And has the lowest runoff potential. In winter, the upstream sediments of the basin with curve number 100, runoff height of 3.81 mm and peak of discharge of 2.65 cubic meters per second and almost all rainfall becomes runoff. Therefore, the shortage of water resources, the presence of dry and semi-arid climates in the country and the achievement of sustainable development leads to the optimal use of water resources.
keywords: hazard, Arc- CN Runoff, GIS, high runoff, catchment Afjeh
The most important role that the managed areas will play to attain sustainable development goals would be protecting ecosystem and genetic diversity to achieve the scientific, aesthetics, social and economic potential benefits in future. Proper management of protected areas requires a full understanding of the present conditions, detailed and exact implementation, planning, regular monitoring and risks changes detection in protected areas to understand how are they, how they would effect on nature, recovery and rehabilitation processes and to protect them in long term is very important. Karkhe National Park and protected area is one of the most valuable and most strategic areas in the country that can be protected. This study aimed to identify and analyze threatening risks in Karkhe protected area and national park. The Study area is located with an area of 15828 hectares (sum of national park and protected area) on both side of Karkhe river in Khuzestan province. In this research based on field visits and using the Delphi technique, that there were 15 experts and specialist joint it, 28 risks in two terms of the natural and anthropogenic environment (physicochemical, biological, economical, social and cultural) are identified. Then to order the identified risks, The TOPSIS method was used according to the three fectors, severity, probability and sensitivity of the host environment. The results showed that the risk of lack of conservative officer by closeness coefficient (CC) 1 is the highest risk in the area and The risk of soil pollution with heavy metals by closeness coefficient 0.149 is the lowest priority. The most obtain risks has been socio-economic risks. After ordering the environmental risks was found that existing risks in the region has been in a considerable level. Finally, strategies to control risk in the region was presented. As a result, management solutions should be provided to reduce, control, or eliminate the most important risks. In the meantime, strengthening the existing environmental laws and the necessary guarantees for their implementation seems necessary.
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