Multispectral remote sensing approach of predicting the potential distribution and evaluating the current spread of water hyacinth (Eichhornia crassipes)

Abstract

The water hyacinth is categorized among the world’s top ten worst invasive plant species of aquatic ecosystems. This study assessed changes in the spatiotemporal distributions of the water hyacinth in Lake Koka and Ziway of the Upper Awash River basin during the peak growth season of the plant. Household questionnaires and key informant interviews along with Landsat images for 2013, 2017, and 2021 were collected to identify the past, present, and future potential distributions of the invasive plant in the two lakes. Household surveys and key informant interviews were prepared using the Kobo Toolbox which monitors data collection online. A total number of 413 households were sampled and the data were analyzed through descriptive statistics. For Landsat images, a supervised classification technique was applied to classify the land use classes using the maximum likelihood algorithm. The survey results showed increased water hyacinth expansion in the area since the year 2011. The water hyacinth expansion affected 285 households’ livelihoods by invading 69.0% of their farmlands which caused 97.6% food scarcity in the study districts. The results of the Landsat image indicated that the water hyacinth invasion in Lake Koka occupied 1.48% in 2013, and this increased to 7.13% in 2021, while the water body decreased from 75.94 to 69.90%, respectively. However, the area of the other vegetation is nearly identical between the years 2013–2021. Likewise, water hyacinth covered 4.66% of Lake Ziway in 2013, and this was raised to 8.42% in 2021. At Lake Ziway water hyacinth invasion affected the area of other vegetation coverage as it decreased from 16.19 to 10.67% but the area of the water body remained almost the same during the years. Between 2013 and 2025, the amount of water hyacinths increased in both Lake Koka and Lake Ziway. According to LULC data, the water hyacinth's rate of spread was 0.56% in Lake Koka and 0.95% in Lake Ziway. The results of this study revealed the signals of LULC change due to water hyacinth invasion in the Upper Awash Basin which is considered an important aspect for future water resources planning and management.