There is a wide variety of species of water plants found in India. When it comes to the subject of Lake Rejuvenation, there are some species that help us read the quality of lakes. In a small quantity, with the right species, these water plants are not very harmful. When these propagate in higher numbers, they can become harmful to the lake.
Let us look at the different types of freshwater aquatic plants to learn more about what they say about the lake.
Water Hyacinth: Water Hyacinth is a very invasive water plant and is one of the most common aquatic plants seen in lakes that need urgent rejuvenation. They spread very quickly in lakes and are known to block the entry of sunlight into the lake beds. Hyacinth also prevents water evaporation thus restricting the natural water cycle. They increase viscosity of the water and create a favorable environment for the growth of mosquitoes and other disease ridden germs.
Water bodies with these plants raise concern as it indicates that:
Nutrient content in water is very high.
Aquatic animals are at risk due to potential scarcity of dissolved oxygen due to these plants.
If infestation is high, the water body is unable to recharge ground water.
Alligator Weed: Alligator Weed is not very common in the southern regions of India and is commonly found in Bihar and West Bengal. Water bodies that have the alligator weed will witness the formation of very dense mats of roots that can restrict movement of aquatic animals. It can spread rapidly in streams and livestock. It is also toxic to some livestock. If a water body is infested with alligator weed:
In small quantities, it houses smaller organisms and supports reproduction.
In larger quantities, the plant has begun choking up the flowing pipes and water outlets.
Water Lettuce: Water lettuce is considered to be commonly present in the water bodies of the world and is not as much a harm to the water bodies as water hyacinths and the alligator weed. These can restrict human activities like fishing and boating. A thick spread of the plant over a lake can cause a degradation in the water quality and may even cause fishes to die. If a lake has water lettuce:
In small quantities, it can help reduce algae blooms and keep the water clear of decomposition byproducts supporting natural purification.
In large quantities, as it spreads rapidly, it can affect water quality and indicate necessity for immediate cleaning up of the lake from the plant.
Water Lilies and Lotus: These plants add colour to a lake and help next the eggs of aquatic animals along with smaller organisms. They can help bring more birds to a lake as well. Growing water lilies should be avoided in water bodies with heavy nutrient deposits as they can grow rapidly and cause infestation that is not safe. Removal of these plants becomes difficult as well. In a smaller and controlled manner, these can add value to an ecosystem. In a lake,
If these plants are there in smaller stretches, they are not really a threat and are just a part of the ecosystem.\
In larger quantities, they can create algal blooms, reduce dissolved oxygen content, indicate heavy nutrient presence and indicate absence of ground water recharge.
Water bodies can have aquatic plants but they need to be monitored. Infestation of aquatic plants, no matter the species, is a cause of concern. It is best to keep the growth in control otherwise the cost of rejuvenation can spike up.