LESSON -1 FLOODS
About Me SNEH KUMAR o M.Sc. in GEOLOGY from University of Lucknovw. Qualified CSIR-NET with AIR 115 JRF in Earth Science category . Qualified GATE exam. Received award of INSPIRE Scholarship from Department of Science and technology Gol during 2012-2017.
WE WILL DISCUSS . The nature and extent of the flood hazard The effects of urbanization on flooding in small drainage basins environmentally preferable. channelization and the benefits of channel . The major adjustments to flooding and which are . The potential adverse environmental effects of restoration.
DEFINITION AND CAUSES . The natural process of overbank flow is termed flooding . Most river flooding is a function of the total amount and distribution of precipitation in the drainage basin, the rate at which precipitation infiltrates the rock or soil, and the topography . Some floods, however, result from rapid melting of ice and snow in the spring or, on rare occasions, from the failure of a dam e Finally, land use can greatly affect flooding in small drainage basins.
FLOOD TYPES RIVERINE FLOODS are the result of heavy precipitation over large areas, of the melting of winter's accumulation of ice and snow, or a combination of both . Riverine floods occur in river systems whose tributaries drain large geographic areas and encompass many independent river basins e Condition Of the ground, the amount of soil moisture, the vegetative cover, and the level of urbanization, where impervious pavement prevents the infiltration of water into the ground
UPSTREAM FLOOD Upstream floods occur in the upper parts of a drainage system .They are produced by intense rainfall of short duration over a relatively small area
FLASH FLOOD Flash floods are among most severe forms of flooding. They are local floods of great volume and short duration. e They occur during violent thunderstorms or cloudbursts on a relatively small drainage area over a short period. They are particularly hazardous if the ground is heavily soaked with water from previous rains or when streams are already at capacity. Flash floods also occur following dam breaks or by the sudden breakup of ice jams, causing the rapid release of large volumes of flow.
A GLACIER OUTBURST FLOOD is a sudden release of meltwater Irom a glacier or subglacial lake and can be quite destructive
FLOOD CONTROL e Flood protection projects include the construction of reservoirs with a storage capacity that can absorb increased flow during floods and moderate the flow rates of rivers. e The dams also generate hydroelectric power. Their reservoirs provide river navigation, irrigation municipal water supplies, fisheries, and recreation o Channelization is the straightening, deepening, widening, cleaning, or lining of existing streams.
Flood prevention requires engineering structures such as artificial levees and flood walls that serve as barriers against high water. e Building reservoirs that store excess water that is later released at safe rates. Increasing the channel size to move water quickly off the land, and diverting channels to route floodwaters around areas requiring protection
Appeared UPPSC ACF Mains ,Completed Masters in Geology.Qualified GATE and CSIR-NET JRF , INSPIRE SCHOLAR I love to share my knowledge with o