Robotic Control of Water Hyacinth in Vembanad Lake

The State Wetland Authority Kerala (SWAK) is launching a one-month pilot project at Kumarakom, Kerala, to control the spread of the invasive aquatic weed water hyacinth (Eichhornia crassipes) in Vembanad Lake through the use of robotic technology.

The project represents an application of technology-based wetland management for controlling an invasive species that threatens aquatic ecosystems and associated economic activities.

Government Framework

The pilot project is being implemented under the National Plan for Conservation of Aquatic Ecosystems (NPCA) of the Ministry of Environment, Forest and Climate Change (MoEFCC).

The NPCA provides a framework for the conservation and management of aquatic ecosystems, including wetlands and other important water bodies.

Vembanad Lake

Vembanad Lake is a major Ramsar Wetland Site and is among the most important aquatic ecosystems of Kerala.

The lake supports biodiversity, fisheries, tourism and local livelihoods. Therefore, the uncontrolled spread of invasive aquatic weeds can have ecological as well as socio-economic consequences.

Water Hyacinth (Eichhornia crassipes)

Scientific Identity

Water hyacinth (Eichhornia crassipes) is a free-floating freshwater aquatic weed belonging to the Pontederiaceae family. It is an invasive alien species in several parts of the world, including India.

Its ability to reproduce rapidly allows it to establish dense populations in suitable freshwater environments.

Origin and Introduction

Water hyacinth is native to the Amazon Basin of South America. It was introduced into several countries, including India, mainly as an ornamental plant because of its attractive purple flowers.

After introduction, its rapid growth and reproduction enabled it to spread extensively in many freshwater bodies.

Rapid Growth and Formation of Floating Mats

The plant can reproduce rapidly and form dense floating mats over the surface of water bodies.

These thick mats can block sunlight from penetrating the water and reduce the availability of light for aquatic organisms and submerged vegetation. They can also contribute to a decline in dissolved oxygen levels, thereby adversely affecting aquatic biodiversity.

Ecological and Economic Impacts

Excessive growth of water hyacinth can contribute to eutrophication and can choke rivers, lakes, ponds and wetlands.

Its dense growth can interfere with several human activities and ecosystem functions. It can disrupt fisheries, navigation, irrigation channels, tourism activities and recreational use.

Therefore, water hyacinth represents not merely a weed-management problem but also a challenge for wetland ecology, local livelihoods and water-body management.

Management of Water Hyacinth

Mechanical Removal

Mechanical removal is one of the methods used to control water hyacinth. Plants are physically removed from the water body to reduce their abundance and prevent the formation of extensive floating mats.

The proposed robotic technology at Kumarakom represents a technology-based approach to this form of control.

Biological Control

Water hyacinth can also be controlled through biological methods, including the use of Neochetina weevils. These insects feed on water hyacinth and can help reduce its growth and spread.

Reducing Nutrient Pollution

Controlling the excessive availability of nutrients is another important management strategy. Reduction of nutrient pollution and sewage discharge can limit the conditions that encourage excessive growth of water hyacinth.

Thus, long-term management requires addressing both the existing weed biomass and the environmental conditions that promote its proliferation.

Potential Uses of Water Hyacinth

Despite being an invasive species, the removed biomass can potentially be utilised for several purposes. Water hyacinth can be used in the production of compost, bio-fertiliser and soil supplements.

It can also be used for making handicrafts and paper products. In addition, the plant can be employed in phytoremediation, a process in which plants are used to help remove or reduce pollutants from water.