ArcSwat based Geospatial modeling of Rainfall-runoff processes in Rupen basin, Mehsana district, Gujarat

Aggarwal Ashish, Srivastava P.K., Tiwari Aman, Chatterjee R.S. and Gupta D.K.

Page No. 1-13

In ungauged localized river basins where stream flow data is rarely available, physical based continuous hydrological models such as Soil and Water Assessment Tool (SWAT) have proved quite useful to assess the importance of spatial and temporal variations of rainfall on runoff generation. The present study focuses on the utilization of ArcSWAT in Rupen watershed of Mehsana district, Gujarat to estimate the rainfall-runoff trends. Parameters like digital elevation model (DEM), land use land cover (LULC), soil data (FAO soils) and data for temperature, rainfall, relative humidity, solar and the wind speed are considered for the model to predict the monthly and yearly runoff at the watershed outlet and estimation of water balance components. Remote sensing data and GIS were used to prepare the thematic maps of the watershed. SWAT simulation was run for a time period of 17 years with 4 years of warm-up period and runoff value was calculated for each sub-basin. Runoff was estimated both on a monthly and yearly basis for 14 years (2004-2017) for corresponding rainfall.

The relationship between rainfall and surface runoff (SurQ) and between rainfall and discharge (Flow_out) was evaluated using correlation coefficient R2. The correlation coefficient for rainfall and the corresponding runoff was found to be 0.871 and for rainfall- discharge it was found out to be the 0.949. The results suggest that there is a positive correlation between rainfall and runoff and shows the effectiveness of SWAT for hydrologic simulations in ungauged agricultural watersheds.

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Risk Analysis and Mapping of Natural Disaster using QGIS tools for Mumbai City

Sansare Darshan and Mhaske Sumedh

Page No. 14-25

Sea levels are rising due to climate change which is projected to rise by significant level by next 100 years and also the rainfall patterns and intensities are changing by virtue of which several parts around the globe are witnessing intense occurrence of rainfall events viz. events of downpour and flooding experienced on the 26th July 2005 in coastal city like Mumbai, which made it a vulnerable city. That is why, the city is vulnerable to a host of natural disasters such as floods, landslides and subsidence of land. Flooding and Landslides in urban areas like Mumbai are major natural hazards causing devastating effect to life, property and infrastructure.

Data generated in QGIS software gives the information about severity and also its geographical location is very useful. After analyzing the different maps from this study, it is clear that majority of flood spots are in the reclamation zone. The deterioration levels of the natural hazards namely water areas, landslides and flood spots were evaluated by considering 100m, 200m and 300m buffers from the above hazard prone zones. The number of affected areas, railways, buildings, roads and population dwelling there was found out. Outfall of the city too waterlogged the city due to backwater effect. Thus, its severity is also analyzed for the same. Maps developed through this research can be utilized by planners, policy makers and stakeholders for strengthening the disaster management plans.

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Hypsometric Analysis and Identification of Natural Disaster-Prone Regions of the Glaciated Bhagirathi Basin, Garhwal Himalaya

Tamil Selvan M.

Page No. 26-33

Hypsometric analysis (or area-altitude analysis) is the study of the distribution of horizontal cross-sectional area of a landmass with respect to elevation. Hypsometric curves and integrals can be interpreted in terms of degree of basin dissection and relative landform age i.e. convex-up curves with high integrals are typical for youth, undissected landscapes, smooth, s-shaped curves crossing the center of the diagram characterize mature landscapes and concave-up with low integrals typify old and deeply dissected landscapes. For this study, SRTM Digital Elevation Model (DEM) data has been extensively used for various geomorphometric analysis of the Bhagirathi Basin, Garhwal Himalaya. The Hypsometric curves always originate in the lower left-hand corner and reach the upper right-hand corner.

The results show that whole of the valley is dominated by low value of Ruggedness index except few places at downstream at junction of the tributaries with main stream especially at lower altitude and main valley. Hypsometric curve shows convex profile which shows that it does not help in active mobilization of the weathered material at higher altitude while weathered material mobilization is quick at lower altitude. This helps to identify and demarcate the natural disaster-prone regions in various altitudes of the basin.

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Snow Avalanche Hazard Vulnerability Analysis of Himachal Pradesh

Arya Rakesh and Sharma Milap C.

Page No. 34-42

Snow avalanches in the Higher Himachal Himalaya are high- frequency low magnitude process since the winter snowfall is a common occurrence, where the slope aspect, relief and surface gradient are conducive for initiation of such failure. Shallow avalanches are common throughout the winter months (snow precipitation related to the mid-latitude westerlies) in higher altitudes, feeding to the glacier mass balance. Depending on the length of run-out distance and catchment area, these avalanches could be termed as routine or catastrophic. However, a single snowfall event contributing over 2-3 feet of snow accumulation in the high probability snow avalanche area may be disastrous, given the existing infrastructures which would be hit in the high probability area comprising only 1.2% of the total geographical area in highly spread-out space of the state. Moderately probable category occurs in about 15% of the geographical area which are mainly confined to higher altitudes that feed glaciers sustenance and mass balance and a small fraction of areas of human activity.

Presently, the state has developed immense amount of infrastructure in such avalanche prone areas, be it roads or bridges, there is a immediate need to develop a mechanism to artificially trigger avalanches in the event of single snowfall spell in excess of 2 feet or more to avoid large scale damage to inhabited areas and infrastructure. The state government constructing all weather roads in snow-bound areas, action-force may be constituted/devised to artificially trigger avalanches in areas which fall in high probability category to keep roads open year-round, whenever there is two-feet or more snowfall in a single spell, the damage to life and infrastructure is minimized in the face of avalanche failure.

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Sustainable Emergency Food Aid Design for the Preparedness of Flood Disaster in Malaysia: A Study Methodology Approach

Balachanthar S. and Lee L.K.

Page No. 43-47

Floods due to intense rain, or climate change, rising population and poorly adapted land use, are the most critical natural disasters to impact on Malaysia. Food aid makes up the majority of humanitarian appeals and remains an important tool in response to the flood events. There is considerable work needed to prepare a definitive design of emergency food aid plan for disaster relief. This study publishes the abridged methodological proposal of this preparatory work.

Emergency food menu will be developed using commonly available food items and local recipes according to the flood severity and nutritional requirements of the following target population: general population, population with diabetes mellitus, cardiovascular disease and kidney disease. Dietary optimization will be conducted in Microsoft Excel using food prices and food composition data to yield low-cost and nutritionally balanced food aid plan that satisfies energy, macronutrient and micronutrient constraints. This plan is expected to serve as national emergence nutrition policy reference for disaster management.

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Impacts of flood and its possible solution in Bangladesh

Md. Humayain Kabir and Md. Nazmul Hossen

Page No. 48-57

Flooding is a regular disastrous event in Bangladesh as it causes serious social and economic losses and damages in the different parts of the country in every year. Moreover, at least one- third of the country is vulnerable to flooding. Sufferings of people due to flood are beyond imagination. Despite its recurrent nature and devastation, the comprehensive research on flooding in Bangladesh has been limited. The aim of this research is to critically analyze the existing flood research conducted so far in Bangladesh. This study used a systematic literature review to understand the flood research in Bangladesh. This review clearly suggests that research related with flood modelling, forecasting and flood management is much less emphasized.

This review of flood research will help the authorities to have an overview of important aspects of flood during planning of mitigation measures and management projects. This in turn, will facilitate mitigation and adaption measures to better respond to the country’s chronic flood problem.

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Determinants of flood mitigation decisions, choices and behavior

Odidi Sylvan, Tantanee Sarintip and Buranajarukorn Panu

Page No. 58-65

Owing to the increase in the frequency and intensity of flood risk across the world, households especially those located in flood-prone areas have been on the forefront of implementing private flood mitigation measures in order protect themselves from the damaging effects of flooding. In addition, their quest for protection is driven by the fact that public mitigation measures such as dams and dikes cannot completely eradicate total flood risk.

This study examines the influence of socio-demographic, geographic and socio-psychological factors of flood mitigation decisions, choices and behavior by reviewing the findings of various authors. The results indicate that most factors have mixed influence. They include flood risk perceptions, self-efficacy, flood experience, dependence on public flood mitigation, age, income and education. While other factors such as response efficacy, social environment, location and house ownership have positive influence, flood mitigation cost has got a negative influence. Gaining insights into factors affecting flood mitigation decisions, choices and behavior are very crucial because of the continuing paradigm shift to flood risk management methods globally as individual households are encouraged and required to contribute to flood risk reduction through risk communication.

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