A beel thicky infested with water hyacinth
A beel thicky infested with water hyacinth
A beel thicky infested with water hyacinth
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sediments are of recent origin and largely consist of silt which can he easily emded.<br />
The Indo-Gangetic alluvial tracts, especially in the northeast, are also geologically<br />
unstable and experience ehquakes of varying intensities from time to time. 'Two<br />
devastating earthquakes occumed in the northeast during 1897 and 1950.<br />
Origin of floodplain wetlands<br />
The lithololgy, yeological structure. tectonic status. seasonal variation In rlvcr<br />
discharge and flow characteristics, largely deterniinc thc formation of the Iluodpla~n<br />
wetlands. The heels of the country owe their orig~n eithcr to the ofic~~ changing course<br />
of rivers in the potamonic stretches or lo tectonic adjustment.<br />
In the northern pan of Bihar and Wcst Bengal its also In Assam. tlic rl\crs<br />
cmcrglng from the central and easten) Htmalayas suddcrtly debouch into tlic plains .~ntl<br />
ultimately flou down as the river Ganga, Brahmaputra and Barak. Tliesc rl\ crs c;~r.l-\<br />
heavy loads of silt and dctritus from the Himalayas and ovcrflo~ dur~ng the sotrtt~ucsl<br />
monsoon season submerging huge tracts of lands every ycar. Ihesc rl\crs changc 111~1r<br />
course vcry oncn creatlng numerous floodpla~n lakes ;ind bralded channels. nia~til! 111<br />
the forni ol'ox-ho\*. lakes. In delta~c Wcst Bengal. due to low gradielit and h~gli rl\crltlc<br />
d~scharge dur~ng Ihc monsoon season. rccha~incl~sat~on of rivers occurs at tlic sl~glltcsi<br />
ob~t~ctlon to flow. resulting in creation of heels of varicd typcs. In thc n~rthc~~sl<br />
(Assam. f~iotli~lls of Arunaclial Pradesh arid Meghalaya), frequent cartltquahcs cuuplcd<br />
w~th heavy ramfall and cuttlng actlon of rlver meanders havc rcsultcd 111 thc Ibnlii~t~O~l<br />
of typical ox-bow lakes, lake-like becis or true tccto~tlc deprcsslons. 'Shc Ilnrs 01<br />
Van~pur owe thetr orlgin mainly to the cutting actlon of the stream nlcandcrs.<br />
Classification of floodplain wetlands/<strong>beel</strong>s<br />
S~nce the floodpla~n wetlands ~n~lude low lying udter bodlcs ul d~versc orlglrt<br />
SIL~, shape. depth, ~nundat~on pattern, ecologtcal charilc~enst~cs, err many dttcmpts<br />
havc been made to classify them according to these cr~terld Somc of thew<br />
class~ficat~ons are glren below