Storm-inundation models based on hydrology and hydrodynamics require a large amount of input data (detailed terrain, sewer system and land use data). In this paper, in order to determine inundation conditions quickly with only a few usually available input data is proposed an urban storm-inundation simulation method (USISM) based on Geographic Information System (GIS). The USISM is a simplified method of distributed hydrological model based on DEM, in this method depressions in terrain are regarded as the basic inundated area. The amount of water that can be stored in a depression indicates the final inundation distribution. The runoff and maximum storage volume for each depression and the flow direction between these depressions are all considered in the final inundation simulation. The SCS method is used to calculate storm runoff and a water balance equation is used to calculate the water storage in each depression. The result shows that in all four-storm event, the average relative depth errors of depth in all inundation sites are less than 20%, while the average relative errors of area and volume are more than 60% Therefore, the USISM method has a higher ability to simulate the final depth of inundation than the surface and volume of inundation. The result reveals that the USISM method could find the inundation locations in the Damghan Urban Watershed and calculate inundation depth and area quickly and therefore display a significant role in the management of the urban crisis.

Storm-inundation models based on hydrology and hydrodynamics require a large amount of input data (detailed terrain, sewer system and land use data). In this paper, in order to determine inundation conditions quickly with only a few usually available input data is proposed an urban storm-inundation simulation method (USISM) based on Geographic Information System (GIS). The USISM is a simplified method of distributed hydrological model based on DEM, in this method depressions in terrain are regarded as the basic inundated area. The amount of water that can be stored in a depression indicates the final inundation distribution. The runoff and maximum storage volume for each depression and the flow direction between these depressions are all considered in the final inundation simulation. The SCS method is used to calculate storm runoff and a water balance equation is used to calculate the water storage in each depression. The result shows that in all four-storm event, the average relative depth errors of depth in all inundation sites are less than 20%, while the average relative errors of area and volume are more than 60% Therefore, the USISM method has a higher ability to simulate the final depth of inundation than the surface and volume of inundation. The result reveals that the USISM method could find the inundation locations in the Damghan Urban Watershed and calculate inundation depth and area quickly and therefore display a significant role in the management of the urban crisis.

In recent years, mangrove ecosystems have been threatened by effects of global climate change, in addition to human destructions. One of the most important impacts caused by climate change on mangroves, is the global sea- level rise and consequently, inundation of parts of coastal zone. Rising sea- level causes mangrove retreat in many areas. However, in some regions, human settlements and coastal structures and facilities, act as limiting factors. In this study, using the two scenarios of the lowest and highest mean sea level rise over the period of 2046-2065, according to IPCC report and the results of internal studies, inundation zones caused by sea level rise in the two protected areas of Harra in Bandar Khamir and Harra Tiab and Minab was determined. Results demonstrated that if the sea level rises, the lowest and highest levels of inundation, will be 1000 and 2000 hectares respectively in Harra protected area, and about 3500 and 7000 hectares, respectively in the protected area of Tiab and Minab. Results of land cover and land use showed that, most of the hinterland, is related to poor rangeland cover and empty lands and according to regional and global predictions in sea- level rise, there is currently no barrier for mangrove migration into hinterland, but in next few years and in the future plans, land use changes need to be addressed to make more appropriate management decisions to protect these valuable ecosystems.

This paper presents a new framework for floodplain inundation modeling in an ungauged basin using unmanned aerial vehicles (UAVs) imagery. This method is based on the integrated analysis of highresolution ortho-images and elevation data produced by the structure from motion (SfM) technology. To this end, the Flood-Level Marks (FLMs) were created from high-resolution UAV ortho-images and compared to the flood inundated areas simulated using the HEC-RAS hydraulic model. The flood quantiles for 25, 50, 100, and 200 return periods were then estimated by synthetic hydrographs using the Natural Resources Conservation Service (NRCS). The proposed method was applied to UAV image data collected from the Khosban village, in Taleghan County, Iran, in the ungauged sub-basin of the Khosban River. The study area is located along one kilometre of the river in the middle of the village. The results showed that the flood inundation areas modeled by the HEC-RAS were 33%, 19%, and 8% less than those estimated from the UAV’ s FLMs for 25, 50, and 100 years return periods, respectively. For return periods of 200 years, this difference was overestimated by more than 6%, compared to the UAV’ s FLM. The maximum flood depth in our four proposed scenarios of hydraulic models varied between 2. 33 to 2. 83 meters. These analyses showed that this method, based on the UAV imagery, is well suited to improve the hydraulic modeling for seasonal inundation in ungauged rivers, thus providing reliable support to flood mitigation strategies.

With the increasing of urbanization, conditions of the underlying surface and climate conditions have been changed by human activities. This resulted in more frequent floods and inundation problems in urban areas. Storm-inundation Models based on hydrology and hydrodynamics require a large amount of input data (detailed terrain, sewer system and land use data). In this paper, in order to determine inundation conditions quickly with only a few usually available input data, an urban storm-inundation simulation method (USISM) based on geographic Information System (GIS) is proposed. The USISM is a simplified method of distributed hydrological model based on DEM, in this method depressions in terrain are regarded as the basic inundated area. The amount of water that can be stored in a depression indicates the final inundation distribution. The runoff and maximum storage volume for each depression and the flow direction between these depressions are all considered in the final inundation simulation. The SCS method is used to calculate storm runoff and a water balance equation is used to calculate the water storage in each depression. The result reveals that the USISM method could find the inundation locations in the Damghan Urban Watershed and quickly calculate inundation depth and area. The USISM is valuable for simulating storms of short duration in an Urban Watershed with a few in commonly available input data.

The climate change issue is dramatically risen by developing of urbanization. This matter of change resulted in more frequent flooding and inundation problems in the urban areas. The urban flood inundation modeling act as an efficient way to rapidly address these challenges by helping disaster managers. This paper introduces a new simulation model of urban storm-inundation. The proposed method uses commonly available input data to estimate the conditions of inundation quickly. The method is based on hydrologic models and geographic information systems. The effects of storm water infrastructures were also considered in inundation calculation. Terrain depressions are regarded as initial inundated area. The amount of surface runoff, the maximum storage volume, the flow direction and the water flow order between these depressions are all considered in the final inundation simulation. A part of region 22 of Tehran was chosen as study area. The results revealed that the proposed method could find inundation locations in the urban area. It can also calculate inundation depth and its volume while considering the effects of storm water infrastructures. A comparison of our proposed model with the USISM showed that the simulated amount of total volume and total depth in our methodology are reduced about 9.13 and 7.12 percent respectively. The lack of consideration of the effects of land-use type and stormwater infrastructures in USISM model is attributed to this difference. The proposed method can be used to create forcasting system for disaster management of flood inundation and helps managers reduce the effects of stormwater disasters.

Introduction: Flood is a natural disaster that threatens the lives of millions of people yearly. Obtaining the flood zone and consequently obtaining the flood zone maps with a specific return period for a reach is one of the important issues. Therefore, estimation of flood maps is required for accurate river engineering studies, flood control projects and planning to reduce the economic and social flood damages. In most parts of the world, hydraulic models are the best ones for flood inundation mapping. However, due to the lack of data and numerical problems, it is not possible to use them for hydraulic simulations. Different of these models, topographically based models such as HAND due to their simple structure and minimum data requirements are the best choice for data sparse regions. Hence, evaluating the performance of the HAND model, which relies solely on topographic features, is one of the objectives of the present project. Methodology: In this study, the flood maps are determined using the HAND model with a calibration based on satellite observations. Seimareh river is selected as a case study to challenge the performance of the model in relation to the observational data and HEC-RAS hydraulic model. In addition, the efficiency of HAND model in low and high flows compared with a 1D and 2D hydraulic model to evaluate the performance of the model in different flow conditions. Results and Discussion: The most important results can be summarized as follows: • The results obtained from the HAND model indicate that this model has the high potential for flood inundation mapping in Seimareh river. The similarity percentages of the estimated and observed flood extents are higher than 92%. Also, the average relative error (ARE) between HAND model and observed flood extents through the study reach is 8. 5%. • The results in Seimareh river show that changing the discharge value does not change the performance of HAND model and the model has a good capability compared to HEC-RAS model. Based on the findings, the similarity percentage of estimated (based on HEC-RAS) and observed flood extents is limited to 83%. The ARE value of HECRAS model in simulation of flood extents is 13%. • Despite the excellent performance of the HAND model in estimating the flood maps, in some parts of the study reach there are differences between the HAND model, satellite images, and the hydraulic model. The main reason of this discrepancy can be related to the extraction and using only one rating-curve for Seimareh river. Therefore, dividing the river into different segments, which contain similar roughness coefficient and river geometry, can significantly increase the performance of the model. • Hydraulic model compared to HAND has more error in estimating flood extents. The main reason for this can be related to important factors such as distance between cross sections, computational dimensions, numerical parameters used in the 1D and 2D hydraulic models (such as θ parameter and currant number), boundary conditions, computational time step and Manning roughness coefficient for each cross section. In general, more factors affect the performance of the hydraulic models and affect theirs outputs, while the HAND model experiences relatively better conditions in this regard. Conclusion: Flood inundation mapping (FIM) is one the key parts of river engineering and flood control studies. Therefore, using a reliable and robust method for calculation of FIM is paramount of importance. In this research, the applicability of a topographic-based method (HAND model) is investigated in Seimareh River. In addition, the performance of is compared with HEC-RAS model and observed flood extents. Findings clearly showed that the HAND model, in spite of having simple structure, performed better than HEC-RAS and estimated the FIM as well as observed flood maps. This model can be used in data sparse regions or large scale reaches in which setting up or running hydrodynamic models is a daunting and time consuming task. Finally, coupling HAND approach with flood warning models can be used as an applicable system for flood emergency management and flood control studies.

In this study two numerical models, one a regional generation and propagation model and the other an inundation model, have been applied to the problem of examining the impact that a large, locally generated tsunami could have on Chabahar Bay facilities in Iran. To achieve a realistic outlook of tsunami hazards in the area, the generation, propagation and interaction of tsunami waves with Chabahar Bay coasts is being numerically modeled for specific events. The modeling is performed using the numerical code which solves the nonlinear Boussinesq wave equations. Results of numerical simulations performed in this study considering past tsunami occurrence records indicate that the multipurpose Chabahar Port is expected to experience the tsunami events with heights ranging between 8 to 10 meters. The model gives approximately the observed maximum area of flooding of Chabahar City. The large and small amount of fooding of Chabahar city coasts, Iran from the 9.1 and 8.3 magnitude erarthquake achieved respectively and extensively flooding was reproduced by the numerical model. The effect of the tide was modeled and found to be small. The results of this study are intended for emergency planning purposes. Appropriate use would include the identification of evacuation zones. The results are used also to find a best configuration advice for the urban facilities in order to mitigate tsunami related risks, with positioning such facilities at the Western Cape of the bay.