Context: The Subarnarekha River has flooded large parts of Balasore district in Odisha, affecting over 50,000 people and inundating dozens of villages.
Relevance of the Topic: Prelims: Key facts about Subarnarekha River; Flash Flood.
Subarnarekha River
- Subarnarekha (literally means Streak of Gold) is a rain-fed river that originates near Ranchi, the capital of Jharkhand on the Chhotanagpur plateau.
- The river flows through Jharkhand, West Bengal, Odisha and drains into the Bay of Bengal. The total length of the river is 395 kilometres.
- Kanchi and Karkari rivers are its chief tributaries.
- Subarnarekha passes through areas with extensive mining of copper and uranium ores. As a result of unplanned mining activities, the river is polluted. It has been the lifeline of tribal communities inhabiting the Chhotanagpur region, and water pollution affects their livelihood.
Flood and Flash Flood:
- Flood: An overflow of water onto normally dry land. The inundation of a normally dry area caused by rising water in an existing waterway, such as a river, stream, or drainage ditch. Ponding of water at or near the point where the rain fell. Flooding is a longer term event, it may last days or weeks.
- Flash flood: A flood caused by heavy or excessive rainfall in a short period of time, generally less than 6 hours. It can also occur even if no rain has fallen, for instance after a levee or dam has failed, or after a sudden release of water by a debris or ice jam. The intensity of the rainfall, the location and distribution of the rainfall, the land use and topography, vegetation types and growth/density, soil type, and soil water-content all determine the intensity and impact caused by flash flood.
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