Detecting Water Hyacinth Infestation in Kuttanad, India, Using Dual-Pol Sentinel-1 SAR Imagery

Abstract

Water hyacinth (Pontederia crassipes, also known as Eichhornia crassipes) is a highly invasive aquatic macrophyte species, indigenous to Amazonia, Brazil and tropical South America. It was introduced to India in 1896 and has now become an environmental and social challenge throughout the country in community ponds, freshwater lakes, irrigation channels, rivers and most other surface waterbodies. Considering its large speed of propagation on the water surface under conducive conditions and the adverse impact the infesting weed has, constant monitoring is needed to aid civic bodies, governments and policy makers involved in remedial measures. The synoptic coverage provided by satellite imaging and other remote sensing practices make it convenient to find a solution using this type of data. While there is an established background for the practice of remote sensing in the detection of aquatic plants, the use of Synthetic Aperture Radar (SAR) has yet to be fully exploited in the detection of water hyacinth. This research focusses on detecting water hyacinth within Vembanad Lake, Kuttanad, India. Here, results show that the monitoring of water hyacinth has proven to be possible using Sentinel-1 SAR data. A quantitative analysis of detection performance is presented using traditional and state-of-the-art change detectors. Analysis of these more powerful detectors showed true positive detection ratings of ~95% with 0.1% false alarm, showing significantly greater positive detection ratings when compared to the more traditional detectors. We are therefore confident that water hyacinth can be monitored using SAR data provided the extent of the infestation is significantly larger than the resolution cell (bigger than a quarter of a hectare).

Phytoremediation Capacity of Water Hyacinth (Eichhornia crassipes) as a Nature-Based Solution for Contaminants and Physicochemical Characterization of Lake Water

“…The sampling station selection was based on human intervention, through industry, city and agricultural actions land graving, and many more related anthropogenic activities. Water plants are free-floating plants, and therefore, field-based measurement carried on a temporal basis is recognized as the standard measurement [43,44]. Therefore, a change due to flotation is under control and less likely to affect the result.…”

Threat of water hyacinth (Eichhornia crassipes) on socio-economic and environmental sustainability of Koka and Ziway lakes, Ethiopia

“…From a health perspective, the WH creates the favourable conditions for mosquito breeding and the invasion of snails and other pathogens that cause malaria and bilharzia (9,21,22). A mat of WH over the surface of a water body disturbs tourism, recreation, irrigation, agricultural production, fishing, and transportation on the water body (9,16,23).…”

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

“…As an invasive alien species, the water hyacinth has a unique ability of producing a large number of offspring and easily spread over a considerable area (Bradley et al, 2022;Rejmánek, 2000). The origin of the water hyacinth is traced to the Amazon basin in South America, and north-eastern Brazil (Oliveira Junior et al, 2021; Simpson et al, 2022). The plant species later invaded Columbia, Guyana, Surinam, Venezuela and to other parts of the world (Karouach et al, 2020;Pagad et al, 2016).…”