Wetland rejuvenation project at Puttenahalli Lake

Invariably these days visitors to the lake ask one question - what are those floating platforms in the water? Those of you who follow our updates on the lake would know that these are the Artificial Floating Islands we had first introduced in June last year. That was also when we signed an MoU with the BMS College of Engineering to test the lake water every month. Three prototype islands were joined by more. The plant species in the platforms increased and the water sampling points went up from four to seven. 

The BMS reports began to show a steady improvement.  The results from site 1 (wetland) for July 2016 and 2017 are given further below along with an analysis of the results.  As laymen, we believe what we see. We see the plants in the AFIs thriving (especially the Canna and how!). We see schools of fish and birds gorging on them (and growing plump!). The eyesore in our lake was the wetland which is a crucial biofilter site but needs to be tended more rigorously than perhaps the rest of the lake since this is the main entry point for rain water. We decided to revamp the wetland which was an unholy mess with trash galore and water snakes everywhere. We came up with a plan to make the vegetation easy to maintain using the floating platforms. 

BBMP cleared the area in February and then again in April. Almost at once, the entire wetland became covered with sticky duckweed. The wetland which looked like a jungle now looked like thick pea soup! We remembered that the duckweed usually kept away during the monsoon hence decided to divert the treated water into the wetland. Voila! The duckweed vanished like magic!

Since then, from May this year our gardeners have been steadily lining the entire inner boundary of the wetland with the floating platforms. Now they are in the process of installing AFIs rows within this bund. The smallest one in front of a silt trap is done. Giving enough space for a coracle, we will perhaps have three to four rows of platforms each with different species of plants. The photos in this link tell the story of our Floating Treatment Wetland:  https://goo.gl/photos/rmHGqJ1GsXai51tb7 

Wetland to the left of the stones, 20th Jun 2016

Wetland rejuvenation in progress, 29th Jun 2017

Our heartfelt thanks to our CSR partners in this project VMWare and Deloitte Shared Services India Pvt. Ltd.  Some of their volunteers made a few platforms as well. We are grateful to BMSCE for conducting the monthly water tests. Ever since we publicised the news of our AFIs last November, several lake teams have been visiting us. We are very happy to share our experience with all. 

See below are the lab reports of  water sample collected from the wetland at Puttenahalli lake. 

                                                      Sample  (Wetland)

Parameter                             July 2016    July 2017

pH                                                 6.81                 7.1

Turbidity                               18.6 NTU        20 NTU          

Dissolved Oxygen                  2 mg/lt          3 mg/lt           

BOD                                        188 mg/lt      62 mg/lt         

Total Solids                         2974 mg/lt      1920 mg/lt

Nitrates                                   68 mg/lt        28 mg/lt         

Phosphates                              21 mg/lt        18 mg/lt         

One of our volunteers, S.K. Srinivas, a pharmacologist, bio-chemist and birder analysed the results. His report is given below: 

"Overall, a good picture. Key points:

BOD (biological oxygen demand) : This is the primary indicator of water pollution. Lower the BOD level, the better is water quality.  Compared to what it was a year ago, the BOD has decreased dramatically.  That's really good. However, since BOD of 20 mg/liter is still considered severe pollution, we have some way to go. But, really good work all the same.

Nitrates / phosphates:   Significant reduction since the past year.  In a literal sense, there is less crap in the water!

Dissolved oxygen:  Has gone up since the past year. Very good. This, I think, is due to the floating islands.

Total solids:    Significant reduction.

Turbidity of the water has increased marginally since what it was a year ago. We need to see why this happening. Turbid water prevents sunlight from getting through the water and decreases plant photosynthesis. It may be due to the increased traffic inside the lake, i.e, increased use of coracle for fishing and weeding. Or it could even be the fish." 

And boy, do we have fish at the lake! :-)

Best

Usha

Artificial Floating Islands in our lake

Those of you who visited Puttenahalli Lake within the past few months may have noticed small platforms floating in the water. These are Artificial Floating Islands (AFIs) which we "launched", starting in June this year. The Vetiver and Canna planted in them are growing beautifully. PNLIT trustee Nupur, her husband Pranshu Jain together with our gardener, Jayanna, are the builders of five AFIs. With volunteers from Deloitte making two last Friday we now have seven AFIs. 

AFIs, Sep 2016

A Coot's nest in one of the AFIs

Deloitte volunteers with the AFIs they made, 25-Nov-2016

Briefly about the AFI - this is a variant of the wetland, an innovative way to improve water quality and keep the lake clean. In this system of Hydroponic Phytoremediation, plants in floating platforms absorb pollutants in the water to grow. AFIs are widely used abroad but not yet popular in India. 

Simultaneously with the AFIs, we began monthly testing of the water. We are delighted to see steady improvement in the each of the eight parameters we measure - pH, Turbidity, DO, BOD, Total Solids, Total Dissolved Solids, Nitrates and Phosphates. Some parameters still need improvement, but the trends are very encouraging. It may be too early to attribute this improvement to just the AFIs since they are few in number. We have been also curtailing the growth of aquatic weeds thereby exposing more water to the sun.  

Our sincere thanks to BMS College of Engineering for testing the water samples every month, their invaluable contribution to PNLIT. To Srinivas SK for analysing the test results.  CSR support from Deloitte Shared Services India Pvt Ltd. enabled us to remove the thick spread of invasive weed from the water, to hire people to keep the water clear of new sprouts as well as to fund the AFIs. 

Usha

Green to Clean

We are delighted to tell you that finally our lake is showing, almost, its true glory! The alligator weed which had covered most of the entire expanse of the water has been removed thanks to funding received from Deloitte Shared Services India Private Limited. 

27-Mar-2016 Before deweeding

18-Apr-2016

Their CSR support enabled us to hire Yellappa and his team of fishermen who began work from 3rd April and completed it on the 20th. They were an excellent group of workers who did not let anything deter them. Not the heat nor the water snakes nor the tangled shoots of the alligator weed which had spread like a large thick sheet over the water. 

Deweeding in progress

Indeed, except for us trustees and a few regular visitors to the lake, almost everyone who spoke to us doubted if there was any water at all in the lake. But little by little the water started to show as the men cut the weed deep down in the water and hauled the strips along for their colleagues to pull onto the land.They piled it along one side of the lake bed which is higher and still dry land. And what huge heaps they made! BBMP helped us dispose these off. They have sent a couple of JCBs to dig deep pits in the lake bed and tractors to fill the pits with the waste. 

We've documented all these through photographs, a selection of which you can see here. Yesterday evening, as if in celebration of Earth Day (22nd April), Yellappa released over 1200 fingerlings in the water. The four species of fish released included the Grass Carp which feeds on aquatic plants. We hope it lives up to its name and keeps the weeds under control. 

22-Apr-2016 Fish being released into the water

It is for the first time since 2009 that the lake has some water at this time of the year. (See here for pictures through the past few years.) This is because rather than depend on the unreliable monsoon, we have treated waste water from South City STP feeding the lake. What a welcome sight it is!     

21-Apr-2016

While we can now breathe easier than in the past few months, our work isn't done yet. We need to ensure that the lake remains free of all invasive aquatic weeds and implement measures to improve the quality of the water. 

It has been a long haul for both the lake and us, trustees, who are driven more by passion than by qualification or prior experience in conservation. We would not have been able to come this far without the help of all our supporters, donors and volunteers. Among many others, we would like to thank especially BBMP (lakes), South City apartment owners' association, Fisheries Dept, and Yellappa and his men. Above all, our heartfelt thanks to Deloitte Shared Services India Private Limited, our CSR Partner in this "Clean Puttenahalli Lake Project". 

- Usha Rajagopalan

Impact Day for Deloitte volunteers

The morning of 27th November saw the coming of enthusiastic Deloitte volunteers to Puttenahalli Lake as part of their yearly  'Impact Day event'.  Around 30 of them gathered at the gazebo to know more about the lake, how it was brought back to life and to find out how they could help.

Mr.S. Sundaresan from Deloitte kickstarted the proceedings by telling the others about our struggle to revive the lake and all the hard work that has gone behind it. As a resident of the neighbourhood (Mr. Sundaresan lives in South City), he had clearly kept himself abreast with the progress updates that are regularly sent out by PNLIT trustees. Mr Ramaswamy (Trustee, PNLIT) elaborated the challenges faced by the PNLIT team and about the long road ahead to complete the transformation. Mrs.Nupur Jain (Trustee, PNLIT) briefed the volunteers about the work that was planned for them to make an "impact" - repairing of broken benches in the gazebo, planting of saplings around the lake. The volunteers divided themselves into teams and set out to work with great excitement. Our neighbourhood volunteers Kalai and Divya, our manager Susheela and gardeners were actively around to coordinate their work. 

Some of the volunteers helped repair the benches which had been broken by miscreants a month ago, guided by the mason who had been called. The volunteers lifted the heavy stone slabs and placed them on the bases, brought bricks, mixed the cement and so on. They also cleaned up the gazebo area. 

Others were immersed in gardening work. From mixing the soil and manure to pushing the wheel barrow loaded with plants and tools, they enjoyed every bit. The hot sun above them did not dampen their spirits and they worked hard till it was lunchtime. It was a joy supervising them and listening to their talk. 

Deloitte had arranged for a quick but tasty lunch for all and then it was back to work. By 3:30 p.m. the volunteers completed all the work that had been planned for them. They were exhausted but deeply satisfied with what they had managed to accomplish that day. 

In appreciation of all their hard work, the volunteers each received a PNLIT wristband. Till their next visit to the lake, these bands that celebrate lakes and the group selfies/ photographs that they took would remind them of their Impact Day at Puttenahalli Lake. 

Sincere thanks to Deloitte volunteers for their contribution to Puttenahalli Lake.

- as reported by Nupur Jain with minor edits