Tuesday, February 13, 2018

Herohalli Lake Report

Authored by Shreyas Sati and Alana Helin as part of the BIOME Trust Wetlands & Lakes Project
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.
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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