Islands of ‘hope’ at Madiwala Lake

Islands of ‘hope’ at Madiwala Lake
By Iffath Fathima

Call it natural tech, but these artificial floating islands are absorbing pollutants from one of city’s biggest lakes


The Karnataka Forest Department has just set up 10 artificial floating islands in one of the biggest and oldest lakes in the city, the Madiwala lake. Call it natural technology, but these islands with special plants act as cleaning agents that help absorb pollutants in the water, thereby keeping the lake water clean.

The artificial floating islands are basically raft like structures. The frames of these islands are made of Polyvincyl Chloride (PVC) pipes and PET bottles, while mesh and coir form the body of the island. Special varieties of plants which absorb pollutants are inserted into the coir. These plants absorb chemicals like excess nitrates, thereby reducing the concentration of these chemicals in the lake.

Looking at the many successful experiments of cleaning lakes through floating islands, the KFD decided to try the floating islands in Madiwala Lake. “We have seen how beautifully the artificial floating islands have benefitted many lakes. Puttenahalli lake and Hebbagodi lake are doing great with the floating islands. Adding these to Madiwala lake will help clean up the lake, ” said Assistant Conservator of Forest, Harshavardhan, Bengaluru Urban Division.

The World Wide Fund (WWF) for Nature was also a part of this initiative. They had been closely studying the Madiwala lake. They had even performed water quality analysis on the lake which showed that the water had a large amount of nitrates, phosphates and ammonia. The artificial floating islands will help in absorbing the chemicals. They have even recorded the species of the birds that visit the Madiwala lake. There are close to 67 species which come near the lake. To keep the birds coming to the lake, the lake must be kept free from pollutants, said experts.

Cleaner plants

The plants used in the floating islands were Typha and Canna, and these help in absorbing chemicals from the water. “These plants grow hydroponically in the absence of soil and removes excess chemicals from the lake water. The islands are easy to maintain and the roots of the plants flow very freely in the water, thereby purifying the water,” said a KFD official.

Students from Vidya Jyothi School, a Kannada medium school, had also come to the Madiwala lake to learn about floating islands. “It was great to see the students come and learn about something different. This was a new concept for them and they were very curious,” said a KFD official.


KFD will be responsible for maintaining the floating islands. “Once the plant has reached a certain height, we will change the plants. We are also planning to introduce floating islands on other lakes,” said Harshavardhan.
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