ASSESSMENT OF SEDIMENTATION IN LAKE CHIRWA USING REMOTE SENSING TECHNIQUE

Sediment particles originating from erosion processes in the catchment are propagated with the river flow. When the flow of the rivers stores water the sediment settles in the Lake and reduces its capacity. Remote sensing data through its spatial, spectral, and temporal attributes, can provide synoptic repetitive and timely information regarding the revised water spread area in a lake. By using digital image analysis water spread area of the Lake Chilwa was calculated to find how sedimentation in Lake Chilwa has affected the size of the Lake and classification image analysis was used to find how land cover changes around lake Chilwa has affected siltation deposit from 2000 to 2020. The study showed that the water spread area of the lake Chilwa kept on decreasing from 1020726900m2 to 792852300m2 for the years 2000 and 2020 respectively due to sediments deposition. The classification results have shown that there is an increase in bare land from 2000 to 2020 around the lake Chilwa which contributed to silt deposition in the Lake.

Remote sensing data through its spatial, spectral, and temporal attributes, can provide synoptic repetitive and timely information regarding the revised water spread area in a lake. By using digital image analysis water spread area of the Lake Chilwa was calculated to find how sedimentation in Lake Chilwa has affected the size of the Lake and classification image analysis was used to find how land cover changes around lake Chilwa has affected siltation deposit from 2000 to 2020. The study showed that the water spread area of the lake Chilwa kept on decreasing from 1020726900m2 to 792852300m2 for the years 2000 and 2020 respectively due to sediments deposition. The classification results have shown that there is an increase in bare land from 2000 to 2020 around the lake Chilwa which contributed to silt deposition in the Lake.

Lake Chilwa is situated in the center of the low-lying Chilwa-Phalombe plain in the southern part of Malawi at 35 ̊15'E and 15 ̊15'S (Ratcliffe 1971). It is the secondlargest lake in Malawi and the twelfth largest natural lake in Africa. It is an enclosed lake with a surrounding reed belt widest on the north and north-east side and a seasonally flooded plain. The water is saline ranging from 1-2% up to 12% during minor recessions.

Traditional authority: Lake Chilwa

District: Zomba

Coordinates: -15.32495, 35.7069