15-Aquatic weeds - Problems control and management to Boost lake environment

Abstract

Aquatic plants have created havoc all over the world. Natural aquatic plants population to some extent is healthy for any aquatic ecosystem as it serves as fish feed, plays an important role in nutrient cycling, purify the water, control unwanted algal growth and support fauna including birds. Unwanted growth of aquatic plants especially some seriously invasive species like water hyacinth and Salvinia has caused a loss of billions of US$ all over the world. It affects the supply of drinking water and water hyacinth (Eichhornia crassipes) has proved to be a persistent and expensive aquatic weed problem costing millions of dollars to control and unaccounted millions of dollars more to the damage to the environment, irrigation systems and crops. Water hyacinth has posed ecological and economical problems in several countries. This weed pose problem especially in tropical and subtropical countries where environmental conditions provide a year round growing period. The natural loss of water from the water surface by evaporation is thought to increase through. transpiration from the leaves of water hyacinth by at least 40 to 50 percent. The dense growth of aquatic weeds obstructs water flow in irrigation channels, interferes with navigation and hydroelectric power generation. The flow of water is reduced by 40 to 95 percent and roughness coefficient increases from 0.024 to 0.055 in irrigation channel. Free floating aquatic weeds interferes with the seed germination and seedling establishment in paddy, resulting in heavy economic losses. Over the years, various control methods have been studied and tried including chemical, biological and mechanical means but with no lasting success. The simplest way to management of aquatic weeds is to harvest it and utilize it for useful products. In order to reduce the cost of transportation a mechanical system has been developed at CTAE, Udaipur which reduces the bulk of freshly harvested water hyacinth up to 73%.