WATER HYACINTH COVER HYDROLOGICAL PATTERN OF KANJT LAKE

Bi-arinual circum-navigation of Kainji Lake between 1996 and 1999 to determine the level of cover of water hyacinth show that the weeds are more abundant in the high water periods than in the low water times. The surveys were undertaken in August (period of low water) and December/January (period of high water). Results from eight surveys show that all the high water periods had the greatest spatial cover totaling 664.86Km2 or 56.18 % compared to low water coverage of 101.74Km2or 8.6%. The reason for this can be attributed to the annual hydrological cycle of the lake which cause the weeds to be pushed far inland at high water and leaves them stranded at shore where they wither as the floods recedes. Over the years the population of water hyacinth at high water dropped from 16 % in 1994 to 10.36 % in 1999 and from 1.9 % at low water to 0.74%. Communal removal, the impact of weevils that feed only-on the plant and the establishment o the boon ' across the lake are all factors that have contributed to this declining trend