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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Clossrjicafion based on depth<br />
i) Shallow <strong>beel</strong>s: Beels having maximum depth up to 5 metres.<br />
il) Medium deep <strong>beel</strong>s : Bcels. which have maximum <strong>water</strong> in the range of 5 to 10<br />
metres.<br />
I~I) Deep <strong>beel</strong>s : Beels having maximum depth of over 10 metres<br />
I) Small <strong>beel</strong>s : Efl'ect~ve area less than 100 hectares<br />
i ~ ) Medium <strong>beel</strong>s : Effective area I00 to 500 hectares<br />
11i) Largc heel . Effective area more than 500 hectares<br />
Ox-bou shaped. crescenr shaped. serpentine, oval, irregular braided channels. ctc<br />
In\estlyat~ons on floodplain wetlands of West Rengal carrted out hq ClFKl for<br />
the Idst decade and A half tndlcate that <strong>water</strong> res~dence and renewal ttme as well as the<br />
extent of nlacrophvtc lntestation are the two most Imponant factors affecting thew<br />
ecology and fisheries In <strong>beel</strong>s that retarn rlvenne connecttons, the continuous <strong>water</strong><br />
exchange affects the nutnent ~npur-output ratlo While this adversely affects the<br />
btologteal productlv~ty of the ecosystem, rt helps rn delaytng eutrophtcatlon process<br />
Raptd <strong>water</strong> rtmewal also helps In breaktng the thermal stratrficalton. rf any, In deep<br />
heel. whtch IS benelicral for nutrlent recycling and gaseous exchange At the same tlme.<br />
continuous Hater flow does not allow the plankton speclcs to stahtltze. resulting in<br />
lower plankton dens~ty and pnmary productton rates tn such heels S~m~larly, aquattc<br />
macrophytes use up large chunks of plant nutrients, thus maklng them unava~lahle for<br />
the growth of phytoplankton (Phytoplankton IS a better prlmary producer than<br />
macrophytes tn heels for efficient conversion of energy) The aquallc weeds also render