Phewa is a stream-fed, dam regulated, semi-natural freshwater subtropical mountain lake which has multiple uses like one mega watt power generation, irrigation, and above all stands as the heart of tourism in Pokhara valley. It extends about 4 km northwest to southeast and is about 2 km at its widest and only a 100 m at its narrowest. It also accounts for rich biodiversity with 7 vegetation types in the watershed area, 104 birds including 14 migratory ones, 34 mammals, 16 fish, 4 exotic fish, 14 reptiles, and 6 amphibian species (IUCN, 1995). In addition, there are 39 aquatic macro-phytes including 23 hydrophytes and 16 helophytes (Shrestha and Janauer, 2001).
Scientific research has shown that Phewa Lake is stretched in area of 9000 ropanis (450 hectare). It is estimated that one third part of Lake i.e 150 hectare of lake area is inflicted by water hyacinth during summer and monsoon seasons.

Water hyacinth is one of the most invasive plant species in the world with a very fast growth rate. It can propagate by vegetative means and through very long lived seeds. Since it has been in Phewa lake for decades, it is nearly impossible to eradicate it completely. While water hyacinth is here to stay, its uncontrolled growth is still undesirable. The rafts of water hyacinth can be an ideal breeding ground for disease vectors like mosquitoes. It can also deprive the water and aquatic organisms of dissolved oxygen and reduce the diversity of life in the lake.
Eutrophication is a kind of nutrient-enrichment process in any aquatic body, which results in the excessive growth of phytoplankton (Beeby, 1995; Rao, 1998). In Phewa, run-offs containing chemical fertilizers used in agricultural land in upstream communities and uncontrolled disposal of sewage from the town area are the two major anthropogenic sources of eutrophication. In this regard, water hyacinth is very efficient both in fully exploiting aquatic nutrients and in utilizing solar energy for profuse biomass production. The rich aquatic biodiversity of Phewa wetland has been seriously threatened due to the depletion of dissolved oxygen in the lake as the water hyacinth forms a layer over the surface of the water-body that inhibits light penetration and re-oxygenation of water through air currents. In addition to this, death and decomposition of aquatic plants further depletes dissolved oxygen and threatens the fish population of the lake.
Water hyacinth also reduces the recreational value of this important lake. The rafts of water hyacinth create obstacles for the free movement of boats, while the decomposing plant matter creates a foul smell and increases water turbidity.

Throughout the world, several methods have been tried, but water hyacinth appears to be a tough plant as it is remarkably resilient. All measures of extermination or control utilizing modern technology, such as those of mechanical, biological and chemical means of destruction, have failed. It has been realized in the case of Phewa that control of water hyacinth cannot be pragmatically achieved since several civil organizations have already spent millions for its removal in past decades and yet these obnoxious weeds have shown no sign of extinction. Instead, they have spread to almost all parts of the lake. At present, efforts and resources are concentrated on removal of weeds at the south-western part of lake where the tourist area is located (popularly known as Lake Side area). Contrary to the existing approach, this project aims to intervene at the source itself so that the problem will be handled more effectively and efficiently. If the action to manage water hyacinth is concentrated at the source itself, it can play a pivotal role in successfully controlling the weeds as well as providing local communities with economic return.

Water hyacinth stems are long and soft which makes it a perfect raw material for the creation of various utilitarian crafts and products. The blending of a modern look with indigenous weaving techniques for the creation of crafts not only reduces environmental waste but also preserves the rich art of weaving which was once an integral part of Nepalese culture and tradition.

The roots and stem of water hyacinth can be used to prepare vermi-compost as the root stores high quantities of nutrients. The use of worms ensures the production of fine quality compost. Hence produced, the compost can be used in agricultural farms which can potentially replace the use of chemical fertilizers. Eutrophication of the lake may be reduced to some extent as the run-offs of chemicals like nitrogen and phosphorus from chemical fertilizers is nullified by the use of vermi-compost.
Phewa Lake along with other 7 lakes have been enlisted as Ramsar sites in 2015.