Flood in General
A flood is an overflow of water that submerges features either man-made or natural that is usually dry and undisturbed portion. Floods are an area of study of the discipline hydrology and are of significant concern in agriculture, civil engineering infrastructures and public health. Due to extensive human activities, often increase the intensity and frequency of flooding, for example, land-use changes such as deforestation and removal of wetlands, changes in waterway course that lead to environmental issues.. synthesia torrent scary anime
Urban flooding is the inundation of land or property in a built environment, particularly in more densely populated areas, caused by rainfall overwhelming the capacity of drainage systems, such as storm sewers. In urban areas, flood effects can be exacerbated by existing paved streets and roads, which increase the speed of flowing water. Impervious surfaces prevent rainfall from infiltrating into the ground, thereby causing a higher surface run-off that may be over local drainage capacity. planswift download
- Many different situations can cause a flood. Here are just a few:
- Heavy rainfall
- Ocean waves coming onshore, such as a storm surge
- Melting snow and ice
- Dams or levees breaking due to debris dam
The summer monsoon brings torrential rainfall in the entire country which lasts for about 5 months in the southern region. Similarly, the winter monsoon brings the massive snowfall over the greater Himalayas of Bhutan.
As the monsoon rain rejuvenates the life back into the mountains, the mountain people prepare for cultivation, animals finally get the greens and flowers blossom, offering an alluring view of mountain slopes. On the other hand, the rainfall brings heavy devastation, especially in southern Bhutan. The frequent landslides obstruct the traffic for days and weeks. The media is flooded with the atrocities caused by the intense downpour. As this story repeats every year much can be done to understand the causes and consequences beforehand through scientific studies. The CDRR&CDS is instituted to approach the floods and likewise disasters scientifically.
Floods occurrence in Bhutan
Flooding causes such devastation that leaves behind a long term scar on the ground as well as on the soul of a victim. The loss of loved one can never be compensated by any flood relief efforts. Thus reflecting upon the past flooding event, a question must be raised. Are we prepared for such an event in the future? If yes, how? and if the answer is no then it is high time to think about it.
A peek on the comprehensive report published by NCHM titled “ Compendium of Climate and Hydrological Extremes in Bhutan since 1968” it is evident that all most all flooding has occurred between May and October with maximum events observed during the month of July and August. Coincidentally the flooding events highly correlates with the rainfall events in the country. If so, although not with a high degree of accuracy but with an acceptable degree, the flooding can be predicted through flood simulation and rainfall-runoff studies in the catchments.
Types of floods in Bhutan
Although the primary cause of floods is intense rainfall, many factors contribute to the severity of the flood. Technically, Flood is defined as a condition when the natural channel is filled and the excess water spill over the banks. Apart from rainfall, glacial lake outburst or landslide dam outburst can also cause a massive flood. Floods are of many types including flash flooding (Gruntfest and Handmer, 2001), flooding due to rising of groundwater (Burt et al, 2002), coastal flooding (Doornkamp, 1998, Nicholls, 2002) and flooding due to the opening of a dam or reservoir. Through the past flood events, floods in Bhutan can be broadly classified into four categories:
- Flood due to prolong rainfall
- Flash Flood which observes in the southern part of Bhutan makemkv registration code
- Glacial Lake Outburst (GLOF)-occurs in the northern part of Bhutan
- Debris Flow- Mostly in Southern part of Bhutan due to formation of the artificial lake as a moraine dam
Strategies to Address the Flood issues in Bhutan
Except for debris flow, the rest type of flooding can be modelled with an appreciable degree of accuracy. In-fact the modelling has proven to be one of the most effective tools for understanding the scenario beforehand thereby providing detail data for analysts and policymakers to develop and prioritize the developmental plan.
Flood management strategies have to be geared towards ‘compensating’ the people of the affected areas after flood occurrence. Very little attention is paid on formulating rational land use planning to reduce flood induced disaster, especially in Bhutan. Preparation of a flood hazard map for the affected regions would be one of the most crucial steps for implementing non-structural and structural remedial measures.
Author: Mr. Leki Dorji & Kirtan Adhikari