Abstract: The present study was designed to understand the long-term impacts
of land-use/cover change on hydrology and nutrient dynamics of Loktak Lake in
Manipur. The major land-use/cover changes are the expansion of built-up land,
open forest land, aqua ponds/water bodies and wetland. There was increase in
built-up land by 0.80%, open forest by 9.39% and water bodies by 1.31%. The
surface inflow from rivers/streams accounts 52% of the total inflow into the
lake. The annual average sediment input into the lake was estimated as 650,000
metric tonnes. The nutrient (DO, free CO_2, chloride, TDS, BOD and phosphate
phosphorous, etc.) levels of the lake varied between seasons and sites. High
intensity of fertilizer usage in the agricultural fields and practice of fish
farming contribute significantly to water quality deterioration in the lake.
The highly polluted rivers (Nambul and Nambol) also finally discharge
pollutants in the lake. Today, Loktak Lake has been placed on the informal list
of threatened Ramsar sites of the world. Only a concerted effort on the part of
official agencies, professionals, NGOs and the local communities to comprehend
the complexities of this delicately balanced, biologically rich wetland
ecosystem, and take appropriate action, can save Loktak Lake from demise.
