Eichhornia crassipes expansion detection using geospatial techniques: Lake Dambal, Oromia, Ethiopia

Abstract

Eichhornia crassipes growth is threatening fresh water bodies such as Lake Dambal. The study's goal is to map Eichhornia crassipes expansion and detect changes from 2017 to 2021. The instrument used to collect field point data was the Geographical Positioning System. The USGS and Copernicus Hub Open Access provided the Sentinel-2 satellite images. QGIS and eCognition software were used to preprocess and classify the images. An accuracy assessment and a feature space plot were used to examine the classified images. Each year's image was divided into five categories: water, irrigated land, Eichhornia crassipes, wetland, and grazing land (Settlement & Iceland). In 2017, Eichhornia crassipes covered 32.51 ha, accounting for 0.06% of the total area of 52,285.4 ha. Eichhornia crassipes coverage increased to 64.92 ha in 2019, accounting for 0.12% of the total area. Eichhornia crassipes was expanded to 317.69 ha in 2021, accounting for 0.61% of the study area. From 2017 to 2021, the expansion of Eichhornia crassipes increased by +285.18 ha (+0.55%). The spread of Eichhornia crassipes around Lake Dambal was rapid. This resulted in socioeconomic issues. As a result, the appropriate authorities should take appropriate action to limit the spread of the weed.

Keywords

• Eichhornia crassipes
• Weed invasion
• Sentinel-2 image
• Segmentation
• Change detection