Sunday, February 25, 2018

Namma shaleyalli beleda banana

Hebbedara Metillu - a small village off Kanakapura Road, that does not even show up on Google Maps. The Head mistress of the lower primary school in the village was keen that RWH be implemented in the school and that the tiny students of the school be spoken to about the need for rainwater harvesting and water conservation. She found our number and requested us for the same. She said she would help us out by identifying a local contractor, material etc and only needed some guidance and some financial support. We managed to raise some funds, go out to the dot on the map and actually managed to get RWH implemented. It rained, their tank filled up and they called to thank us. About a year has gone by since. Now they send us this "Namma shaleyalli beleda banana" (banana grown in our school) - and ask us to swing by and eat their delicious bananas. This was grown with harvested rainwater !!

Saturday, February 24, 2018

Community Groundwater Management in Shantinagar

One of the streets in Shantinagar very close to the BMTC bus depot, floods every rain - upto 6ft standing water, manholes overflow, gets very little or no Cauvery water for most parts of the year. People have dug their own borewells 600ft and deeper but they yield very little water. Most people on the street (about 50 homes) have lived there for more than 30 years and have seen the area grow. The community is very close knit and has known each other forever. Recently drain works have been taken up by the BBMP to clean the larger drains, increase the diameter of the UGDs and storm water drains so as to deal with the flooding issues. As a part of the work the corporator is also considering digging a common borewell and laying supply lines to each of the homes from the borewell. 

One of the ladies from the community called BIOME to explore possible solutions to deal with their water issues. We managed to squeeze a visit to Shantinagar into our schedule and could inform them only a day in advance. It was amazing to see the large turnout for the meeting at short notice. The possibility of investing the "borewell" money for groundwater recharge was suggested and discussed. With some conversations between BIOME and the community it was apparent that the new borewell had little or no chance of being a steady source of water. The recharge wells on the contrary at least would increase the groundwater table. Some more conversations and people took us to see their old open wells. The wells still have water and have not been used in very long. There are memories of the well having water and the well being the source of drinking water when one of the ladies moved into the locality as a new bride. The wells do look unused and there seems to be some contamination as well. BWSSB water is many a time contaminated too. The residents are now keen to revive their opens well, invest in community recharge, implement RWH in each of their homes. The story has to still unfold but we are confident there will be a happy ending and plentiful water when they need it 
The meeting

Water at 8ft below ground level

looking around 

another well - water is cleaner - with RWH

Wednesday, February 21, 2018

TG Halli Reservoir Report

TG Halli Reservoir(TGR), also known as TG Halli Dam or Chamarajsagar, is a man-made reservoir built by constructing a dam in the year 1933. The reservoir lies at the confluence of Arkavathy River and Kumudvathy River 35 kms west of Bangalore[2].

The size of the TGR is as follows:
Catchment area
1453 sq. km
Covers parts of Doddaballapur, Nelamangala, Devanahalli, Magadi and Bangalore taluks.[3]
75 ft
Storage capacity
3.345 tmcft(Approximately 280,00,000 cum)                     1 tmcft= 2.83168466×1010 litres

During our visit to TG Halli on 18/01/2018, we observed that there isn’t any walking path around the lake, however, the reservoir has multiple entry points to reach close to water body. There is no STP at the reservoir, but during our visit to the reservoir, we were told that the treated water from Nagasandra STP joins the Arkavathi river before it enters the reservoir.

While there are no constructed wetlands throughout the reservoir, we observed natural growth of wetland species such as Water Hyacinth at certain points in the reservoir.

 TG Halli Catchment area[4]

Overview and Observations
The water from TGR is currently being used for irrigation purposes. However, until about 2012, the water was being used for drinking purposes as well. Because the water quality was found to be substandard and the water quantity reducing significantly, its usage for drinking purpose stopped[1]. 

There have been numerous articles on the water quality of TGR which mention that the TDS was beyond 500 ppm and both BOD and COD were way higher than acceptable levels. But, due to heavy rains Bangalore has witnessed this year, it was said that the water quality has improved to an extent that the TDS, BOD, and COD levels of inlet water at the confluence of Arkavathi and TGR were 450 ppm, 5 ppm, and 120 ppm respectively. The BOD and COD of the water at the outlet after the TGR water has been treated using WTP are 4 ppm and 30 ppm, respectively. The current level of the water is 66 ft and it was said that the water level has significantly increased in the last 6 months owing to heavy rainfall.

Water Hyacinth is found to grow in certain parts along the edges of the reservoir.

We observed significant algae buildup on the sides of the reservoir and the water colour seemed to be greenish.

Fishing is done in TGR. However, more information about who is allowed to fish is not available.

The Reservoir
Two inlets from which water would enter TGR are summarized below.
Arkavathy River
Mix of storm, sewage, treated STP water and effluent from various industrial estates enter the TGR through Arkavathi river. The engineer incharge of TG Halli informed us that Arkavathi river flows through Harekyathnalli, Kithnalli Bridge and Varthur Bridge before entering the TGR near Naganalli.

Kumduvathy River
We were told that currently, no water enters TGR through Kumduvathy river as the river has dried up.  

Pictures not available

There is one reservoir outlet which flows through a channel after the TGR water is treated using WTP. This water is being used for agricultural purposes and further flows into Manchinabele and Mekedatu Rivers.

The Nagasandra and Chikkabanavara STPs which are of 20 and 5 MLD capacities are upstream of TGR. It was said that the Nagasandra STP treated water is let into the Arkavathy river which enters TGR. However, we believe that treated water from various STPs could enter into Arkavathy river.

The Wetlands
Currently, there are no constructed wetlands in TGR. However, we observed floating wetland species along the edges at some parts of the lake.

It was reported in Deccan Herald on 30th Jan 2018 that the ambitious project to treat sewage in Arkavathi river flowing into TG Halli has been awarded to Hyderabad based Akhil Infrastructure Pvt Ltd. The cost of the project is 11.49 crore rupees and the technology that would be adopted is Natural Biological System(NBS) which uses engineered wetlands to treat wastewater.

Contact Info
Dr. P. N. Ravindra- CE(BWSSB): 09845444127,
Vivek- AE(BWSSB): 07411797586
Chetan-Engineer/Chemist(BWSSB): 08095843909,
Ramakrishne Gowda- AE(BWSSB): 09845655146


Tuesday, February 13, 2018

Herohalli Lake Report

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

Lake Area
35 acres
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.

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.

The Lake
Four inlets where water would enter Herohalli Lake were identified and are summarized below.
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.
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.
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.
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.

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

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.
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