Monday, October 30, 2017

Mahadevapura Lake Report


Summary
Mahadevapura Lake is on 22 acres and is located in the east of Bangalore between Purva Parkridge and Durga Rainbow Apartments. It is frequented by many local residents who enjoy the provided walking path. Currently, no STP exists in the lake premises, however there are plans for a 1 MLD Dewats STP to be setup by CDD. There are two wetlands, one in the southeast and the other in the northeast of the lake. In total, there are 4 inlet points and 1 outlet from the lake. Of the 4 inlets which carry sewage, 3 overflow into the lake during any flood event and one enters directly into the wetland area that is to the southeast side of the lake. The volume of inflow through the inlets could not be determined.

Mahadevapura MyMap.png



Overview and Observations
Mahadevapura Lake is located in Mahadevapura, Bangalore.
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Lake Area
22 acres
STP & Wetlands
No STP exists within the lake premises. However there is a proposed plan to commission a 1 MLD STP for which necessary government approvals have already been obtained.

There are 2 wetlands in this lake.
Until 2014, the lake was under the jurisdiction of Lake Development Authority(LDA). Due to lack of funding, LDA was unable to control the flow of sewage into the lake and therefore the jurisdiction of the lake control was shifted to BBMP1. With a budget of about 3 crores, the BBMP began the implementation of lake rejuvenation in early 20162. There are four inlet points, two of which are naala overflows, one is diversion drain overflow, and the other flows directly into the wetland area in the southeast of the lake. There is one outlet from the lake. Along the eastern side of the lake, there is a sewage inlet into the diversion drain (POI 1) which does not enter the lake and flows through the diversion drain.
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POI 1 - Diversion drain inlet on the eastern side of the walking path along the fence.

The lake premises are surrounded by a fence through which there is one entrance. In the mornings and evenings, many local residents use the 1.5 km path around the lake for walking, jogging, or other workouts.

The Lake
Four inlets where water would enter Mahadevapura Lake were identified and are summarized below.
Inlet
Name
Description
Photos
1
Culvert Inflow
Discharges into the wetland that is to the Southeast of the lake. This is the only inflow which flows directly into the wetland/lake. The rest of the inflows are overflows into the lake.
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2
Diversion Drain Overflow
Along the eastern perimeter of the lake, this diversion drain exists which overflows into the lake through two culverts during flood events
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3
Naala 1 Overflow
Overflows through a bar screen into the lake under a bridge from the Northeast direction. Source of flow is undetermined.
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4
Naala 2 Overflow
Overflows through a bar screen into the lake under a bridge from the Northwest direction. Source of flow is undetermined.
The region of water after the overflow is separated from the rest of the lake by a bund.
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The outlet from the lake is an overflow system under a bridge in the SW corner of the lake.
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Overflow outlet from Mahadevapura Lake

There was no apparent buildup of algae around the lake, nor was there any strong sewage odour.

The STP
Currently, there is no STP at Mahadevapura lake. However, we have learnt that an STP of 1 MLD capacity will be commissioned in the near future for which necessary approvals from the government authorities have been obtained. The vendor of the STP will be CDD and the technology is Dewats. However, we do not know the location of the STP in the lake premises.

The Wetlands
There are two wetland areas at Mahadevapura: Wetland 1 in the SE corner and Wetland 2 in the NE corner. Both are separated from the main lake by a bund and the raised walking path, respectively.

Both wetlands have a large number of plant species throughout which cover most of the surface. Because of this, any sewage that may enter these wetlands would undergo some treatment. Large solids may settle and be filtered as the water passes through the stones and plant growth on the bund between Wetland 1 and the main waterbody of the lake.
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Wetland 1 - SE wetland pictured above (facing southeast).  

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Wetland 2 - NE wetland pictured above (facing northeast). Sewage drain discharging from right-hand side.

Contact Info
BBMP : 08022221170

References


Saturday, October 28, 2017

Byrasandra Lake Report

Summary
Byrasandra Lake is on 10.2 acres and is located in the south of Bangalore near the NIMHANS hospital. The lake lies within the Puttenahalli Lake series within the Koramangala-Challaghatta Valley. It is frequented by local residents who enjoy the provided walking path and gym, though laying of pavers is still in progress. No STP exists in this lake, however a well-demarcated area of wetland exists to the west of the lake. There are two inlets, one into the wetland area and the other into the main lake from the wetland through a weir under a bridge. The inlet predominantly carries stormwater, but there have been many cases when the sewage lines clog, resulting in the backflow of sewage which enters into the storm drains and finally flows into the wetland area. The volume of inflow through the inlets could not be determined.

Byrasandra MyMap.png
Map 1


Overview and Observations
Byrasandra Lake is located in Jayanagar, Bangalore. Dr PU Antony, Professor of Zoology at Christ University and the founder/mentor of Green Army, has been declared as the warden of Byrasandra Lake by the KLCDA.
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Lake Area
10.2 acres
STP & Wetlands
No STP exists in the lake premises, however a 0.6 acre natural wetland exists to the western side of the lake and there have been some discussions regarding the construction of an STP in the future.

There are many activities in the lake premises that are being funded by the BBMP and have been undertaken by their contractors. The work which has been undertaken within the past 8 months includes: fencing, cemented walls near residential colonies, paving, cleaning/deweeding, diversion of inlets to a single line leading towards Agara, construction of gym, and tree planting. There are 2 inlet points. One inlet enters into the wetland from an approximately 30 acre catchment area which includes: the NIMHANS region, Gulbarga Colony, and Tilak Nagar. It was reported by the security of the lake, Mr. Yellappa, that the rainwater enters the lake only during a flood event when the storm drains fill completely. The second inlet is the inlet into the main lake from the wetland region. It was also reported that sewage enters the wetland as a result of backflow when the sewage line clogs during a flood event.

In the mornings and evenings, local residents use the 0.8 km path around the lake for walking, jogging, or other workouts.

The Lake
Two inlets where water would enter Byrasandra Lake were identified and are summarized below.
Inlet
Name
Description
Photos
1
Wetland Inlet
Stormwater and sometimes sewage (during flood events) flows into the wetland from NIMHANS region, Gulbarga colony, Tilak Nagar etc.
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2
Lake Inlet
The outlet of the wetland is the inlet to the main lake and flows through a weir under a bridge.
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The outlet from the lake is an overflow system under a bridge in the NE corner of the lake.
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Overflow outlet from Byrasandra Lake

There was minimal buildup of algae on the water surface. In the center of the lake, the depth may reach 9-10 feet.

Along the walking path, there is a gym near the gate and a filled kalyani along the western edge of the lake (see Map 1 for locations).
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The STP
At present, no STP exists at Byrasandra Lake. However, there have been discussions with the government authorities to build an STP. The nearby university was approached by Mr. Mallikarjuna who asked them for help in funding the STP if possible. These discussions are in early stages and so there is very little information available regarding the STP.

The Wetland
There is a 0.6 acre, 2 foot deep natural wetland at Byrasandra in the west side of the lake which  accounts for about 6% of the total lake area. The wetland is separated from the main lake by a bund/walking path, though there is a bridge under which water will flow from the wetland into the lake.

The wetland also has a large number of wetland plants throughout, though they did not cover the entire area.
20170920_083159.jpg
Wetland pictured above

We were told by the security that the wetland is regularly maintained by either trimming the vegetation growth or removing some species of the vegetation growth. At this time, we are uncertain of the effectiveness of vegetation removal as a method of wetland maintenance as it may impact its capacity for nutrient removal.

Contact Info
Byrasandra Security : Yellappa : 0 85499 76146
BBMP Incharge : Usha Rani : 98860-46498
Green Army : greenarmy@christuniversity.in
Dr P U Antony, Initiator, Green Army : 91 80 4012 9319 

References


Friday, October 27, 2017

All Citizen Lakes Dashboard Updates

This ongoing blog will capture all the updates (on Facebook) done so far on the Citizen Lakes Dashboard project. Links to those posts will be provided here and updated whenever a new post is made. Since the posts are "public" the links to them should also be accessible to those without Facebook accounts.

There is a dedicated Facebook page for the project - https://www.facebook.com/bcld5/ and all posts are made from that page

Posts in 2017-------------------------------------------------------------------------------

Latest post
Oct 27     :  https://www.facebook.com/bcld5/posts/158984981365740

Older posts
May 26   :  https://www.facebook.com/bcld5/posts/149353562328882
March 10: https://www.facebook.com/bcld5/posts/149353438995561

Koramangala Rain Gauge

From the street, the house I visited looked like any other. I was greeted at the door and led up to the terrace where I met Clement Silva. At the time, Mr. Silva was in the middle of one of his daily rituals - watering his garden. In among his plants sat the object of my interest and what set this house apart from others: a home-made rain gauge.



When asked, Mr. Silva explained that he noticed the rainfall recorded in the newspaper did not seem to match what he experienced at his home in Koramangala. To better understand the rainfall patterns in his neighbourhood, he did some research and decided to make his own rain gauge. After gathering the necessary parts – a funnel and large container – from a laboratory supply store opposite Christ University (details below) and having a glass graduated cylinder made, Silva had a complete rain gauge ready to go – and all for less than Rs. 350!

He has now been recording rainfall data on a daily basis since 2009. After taking the reading, he divides the amount by four to correct for the difference in diameters of the funnel and graduated cylinder. Any rainfall in excess of 58mm (the maximum amount the inside cylinder holds) is captured in the can and poured into another graduated cylinder before being added together for the total amount. This number is then written down on a sheet which Mr. Silva created specifically for rainfall data. At the end of the year, the data is saved to a computer and a new sheet is started.


Around three years ago, Silva also implemented RWH for recharge (contractor details below) following the BBMP mandate at a cost of about Rs. 20,000. At the same time, he decided to have small RWH structures installed to capture rooftop runoff. The structures are simple 6” PVC pipes used to encase a downtake pipe with a nozzle on the bottom. The captured water is used for the daily watering of ground-level plants which do not receive rainfall since they are shielded by the roof and building.


 

Rain gauge components obtained from:
              Laboratory Traders
11/1 Hosur Main Road
Bengaluru 560 029
Phones: 25536800 / 41106000

RWH Contractor:
              Drop by Drop
              PSR Arcade, 4th Floor
              1 Guddadahalli Main Road
              Hebbal, Bengaluru 24
              Mobile: Suchethana - 94485 30176

Note: This implementation took place in 2009 - the contractor, components, and costs may vary/be unavailable at this point in time.

Wednesday, October 25, 2017

Herohalli Lake Report

Summary
Herohalli Lake (water body area of about 25 acres) lies on approximately 35 acres and to the west of Bangalore between Andrahalli Main Road and Magadi Main Road. Herohalli is part of the Madavara lake series within Hebbal Valley. It is frequented by many local residents who use the provided walking path, kalyani, and other amenities. A 1.5 MLD Soil Biotechnology (SBT) STP exists in the lake premises which currently is not operational. No constructed wetlands exist in the lake. However, there are areas within the lake which have been separated by the bunds but have no vegetation except for significant algal growth. In total, there are 4 inlet points and 1 outlet from the lake. Inlet 2, which is the STP treated water inlet, does not discharge treated water into the lake as the STP is not operational. Inlets 1 and 4 are overflow inlets(overflows during a rain event) which carry a mix of sewage and stormwater. Inlet 3 is also an overflow inlet(overflows during a rain event), but which carries a mix of sewage, chemical effluent, and storm flows through the diversion drain to Malathalli kere and then towards Kengeri. The volume of inflow through the inlets 1, 3, and 4 could not be determined during the non-rain event.



Overview and Observations
Herohalli Lake is located in Sunkadakatte, Bangalore.
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Lake Area
35 acres
STP
Capacity: 1.5 MLD, but not operating; Design: Soil Biotechnology

There are 4 inlet points, of which one is a treated water inlet and the other three are overflow inlets into the lake. The three inlets when not overflowing flows into a diversion drain which flows towards Kengeri through Malathalli lake. We were told by people at the lake that the inflows to the lake include sewage from the Peenya and Madeshwara Nagara areas. There are no wetlands in the lake. Significant algal growth was observed, especially along the edges and in those areas that are separated by bunds. A few locals mentioned a strong sewage odor will often occur after a significant rain event. We were told that the area within the bunds is typically cleaned once every 3 or 4 days.
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In the mornings and evenings, many local residents use the 1.5 km path around the lake for walking, jogging, or other workouts. There is a kalyani and a gazebo on the northern part of the lake. We observed that there were no toilets all along the 1.5 kms perimeter of the path. There are three entrances: one in the north, one in the northwest, and the other in the south of the lake. Contracted fishing is also allowed at the lake.
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The Lake
Four inlets where water would enter Herohalli Lake were identified and are summarized below.
Inlet
Name
Description
Photos
1
Naala 1 overflow
During a rain event, the Naala 1 overflows into the lake from the northern direction. Otherwise, it flows through the diversion drain in the eastern direction. The Naala 1 carries a mix of sewage and stormwater.
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2
STP treated water
Currently, the STP is not functional and therefore there is no discharge into the lake. We were told that when the STP was functional the quality of the treated water was of good quality.

The water level in the lake was high and had submerged the treated water inlet. Therefore we were not able to see the treated water inlet.
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3
Naala 2 overflow
During a rain event, the Naala 2 overflows into that part of the lake separated by the bund from the eastern direction. Otherwise, it flows through the diversion drain in the southern direction. The Naala 2 carries a mix of effluent from industries, sewage and stormwater.
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4
Naala 3 overflow
During a rain event, the Naala 3 overflows into that part of the lake separated by the bund from the eastern direction. Otherwise, it flows through the diversion drain in the southern direction. The Naala 3 carries a mix of sewage and stormwater.
20170926_073457.jpg

The outlet from the lake is an overflow system under a bridge in the Southern side of the lake.
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Overflow outlet from Herohalli Lake

The STP
The STP at Herohalli is owned by the BBMP and was constructed in 2014 for about Rs. 2-3 crore2. The STP is capable of treating 1.5 MLD of sewage. Currently, the STP is not functional and we were told by the security at the lake that the reason for that is due to lack of manpower. During a visit with the BBMP on 23 October 2017, we were informed that the STP is expected to be operational in about five months following the construction of a silt trap prior to the inlet of the STP. The treated water is piped directly into the main part of the lake.
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The treatment plant is based on a technology called the Soil Biotechnology, a natural treatment system which uses microbes present in the soil coupled with engineered filtration units to treat the wastewater.

The Wetlands
There are no wetlands at Herohalli Lake.

Contact Info
BBMP : 080-22975648 / 22975601

References