A beel thicky infested with water hyacinth

In Irld~a. the State of Assam has the maximum number and water area under
Ilot~tlpla~~i uctlands, malnly assoc~ated wlth the nvers Brahmaputra and Barak. Locally
~IIOWII 'IS heels, they arc n~ostly oxbow lakes, backswamps or tectonlc depressions The
prudonliruancc of lloodplaln wetlands In Brahmaputra basin 1s attributed to the oftcll,lng~ng
course of rivers and thelr tr~butar~es In the upper stretches. The Fiver
14r.1l~1nirp~1lra passes through 'ones of acute seismic actlvlly. Frequent earthquakes due
to crustal lnstahility Induce local and sudden shifts in basement levels Th~s coupled
u~th Iicavy dlschargc of water trlggers the process of meander cutoffs leading to
formitt~on of oxhow lakes Tecton~c depress~ons are also formed due to eanhquakes.
S~clrilarly, thc Brahmaputra is prone to frequent and heavy floods, which break the
Ic\ccs Ic;ldlt~g to fbrmation of back swamps and sloughs. Assam has 1.392 beels spread
ovcr niorc than 100.000 ha. Th~s lncludes 322 on the river Barak In the d~str~cts of
Ila~ldkand~. Kar~mganj and Cachar with a uater spread of 8,000 ha. Total area of beels
;~~sociatcd wlth tlic river Brahmaputra and its tributaries in Assani is estimated at 0Z.OOO
ha
Assall1 occup~cs an area of 78.338 km', the two important physlcal reglons of
the S~i~tc Jrc tlic Oarilk \alley (6.062 kn" dr~d tile Brahmaputra \alley \50.349 krn') 7'hc
:.orlo kni 1011g rI\cr Wralilnaputra entcrs tllc statc through the riorthcas!cnl distric! of
l~~ilii~k~;~
;it iiti cIe\at~on of' Inore than hOO ni ahovc MSI- and passes Iongltud~nall)
tl~~oi~gli IIIC \allc? ( 150 In ahovc MSl.) hcfore enrerlng Banglsdcsh through Dhuhr~
tl~str~st lllc \bllolc northcrn pan of the State is bordered by t11rnala)an h~lls. ranging III
hc~ght hct\\ccn 150 and 600 m above MSL. (aid sometlmcs between 600 and 1350 m
MSI ) 'l'ticsc li~lls give nse to nuny fast flowing rivulets flowing downwards and
~ilt~tiii~icly lncctlng Brahmaputra. Mik~r and Rengma hills. located centrally at the
clcviition of 150 to 1350 m are the ongln of many streams. North Cachar hills and Boral
rallgc (at .I relatively low elevat~on of 150 to 600 m above MSL) IS the source of Barak
Ilvcr system l'hcsc two river systems form a network of as 111any as 33 major
trlhut.lrlcs. Altogether, there arc 121 streams including distributaries (Fig. 1 )
'fhc State rccetves one of the h~yhest rainfall in the world ranging between 178
.rnJ 705 ern. In some places exceeding 400 cm. Soil character~st~cs of the regton IS
clo~n~r~atctl h! old alluvial types, however, areas along the bank of nver Brahn~aputra
p;~rt~r~~l;~rly 111 the lower reaches the soil is recent alluvial. Areas adjacent to Mik~r h~lls.
Kariglnd Iillls illid North Cachar are character~zed by either red loam or laterite soil.
Forcst co\cr of the State esttmated to be approximately 26%. most of which are
e\crgrccn fcircs1s. wet grass lands and dry grass lands.