Tuesday, August 9, 2016

Adarsh Palm Retreat, Bellandur: Road to Achieving Sustainable Extraction of Groundwater

With widespread extraction of groundwater in Bangalore, the search for a sustainable solution for the usage of groundwater is the call of the hour. What has been a repeated cause of worry in terms of supply has been the drying up of borewells that are an integral source of water to a majority of the population. In a scientific point of view, the borewells are our access points to what are called the ‘intermediate aquifer’ and the deep aquifer’. Intermediate aquifers can be found at a depth of 30 m to 40 m below ground level and the deep aquifers found at a depth of 150 m or lower. What has been the case for the past few years has been the vanishing of the intermediate aquifers, which has forced the digging of borewells further to try and extract from the deeper aquifers.


Particularly in the South Eastern part of Bangalore, the Sarjapur Road area and its surroundings, most borewells are preposterously deep, going as low as 1000 feet in search of water, and sometimes still failing to identify a sustainable source of water. Therefore we are now approaching a reality where having extraction of groundwater from where we live is as close to not being possible, for the resource has been nearly exhausted. 

The BWSSB supply of the Cauvery River water is non-existent in this part of the city in terms of infrastructural connection. In terms of the quantum of supply of BWSSB water, a bleak picture is being painted on that front as well. Currently, the Cauvery Water Supply Scheme (CWSS)  Stage I, II, II & Stage IV Phase I and II amounts to the total allocated water from the Cauvery River provisional for Bangalore city. The total installed capacity as of right now is 1310 MLD. Below given is the water supply requirements based on the future anticipated populations. Notice the amount of shorftfall in demand, which is already being experienced.

Source: https://bwssb.gov.in/content/about-bwssb-2

As it can be seen above, to put it bluntly, we just do not have enough supply of water to meet our basic needs, let alone our over consumption! Therefore, alternative sustainable options must be administered in order to solve such a crisis. A good example of such an occurrence is in Adarsh Palm Retreat who are fortunate to have an alternative resource in place that can aid in reducing their current dependency on unsustainable sources. 

Shallow Aquifers: Back to the Good Old Times!

Above, it was mentioned that our borewells largely tap onto the intermediate and deep aquifers. There is in fact a third form of aquifer that has been somewhat forgotten, the shallow aquifer. To say the least, this groundwater resource very close to ground level is not unheard of. We were in fact supporting our basic needs through this resource for thousands of years, while having access through open wells! The case of Adarsh Palm Retreat (APR) is a symbolic attempt to kind of back track our preexisting technologically advance solutions and revert to a simple solution that will provide far more sustainable results.  

Through a study done by Biome, a solution was identified to reform the water management strategy that is in place for the community. It was established that right under the 128 acres of APR, there lies a humongous resource in the form of a shallow aquifer, or to simply put, groundwater found at a depth of 10 m below the ground. This resource was disguised in the form of a problem for the residents, as during the rainy months, there was sever flooding that occurred in certain basements of houses. This provided Biome a suspicion that there seems to be a hidden resource in plain sight. After some deliberation, the size of the aquifer was identified with respect to APR's boundaries. Below given is information on the aquifer.

Weather Zone
10
m
Specific Yield of Aquifer
0.060

Storage
310976
KL
In terms of rain
600
mm of rain

The weathered zone, in effect the depth of the shallow aquifer has been taken as 10 m which is a conservative assumption made that needs to be ascertained. However, with the consultation of leading hydrologists with vast experience, it is certainly a good working assumption for now. To simplify the above data, the capacity of the aquifer has been determined to be  600 mm of rain. Now with an overall objective to harvest this aquifer twice in a year, which would amount to 1200 mm of water in terms of rainfall provisional for usage. With comparison to 2015's rainfall of 1188 mm this will ensure the utilization of the entire rainfall received in a year. With a systematic approach, this somewhat giant storage unit can be fed rainwater and extracted reasonably all throughout the year. This in turn can aid in reduction of dependency on other not so reliable resources such as tanker water. 

In the given below link is a quick presentation summarizing the story of APR and how this solution can be of benefit to the community-


Great! How do I tap this Shallow Aquifer?

Finally, a solution would need to be developed in order for the extraction of the water from this shallow aquifer. However, it must also be bared in mind that this solution can only be considered sustainable if adequate amount of water is also recharged into the aquifer. Therefore, there needs to be a system in place that will ensure a balance in withdrawing as well as in recharging. This can be conducted by having a network of withdrawal wells, that will be the extraction point for the water to be transported to the water treatment plant. Alongside, there will be an adequate number of recharge wells, whose purpose would be to recharge the well and that can be done by harvesting the rainwater runoff on APR's boundaries. 

The first withdrawal well was constructed on Phase 2, Lane 8 of APR. The well has a diameter of 5 ft and a depth of 25 ft. The volume of the well is around 12,000 L. Here are some photos of the withdrawal well.






Here is a quick video explaining the use of the withdrawal well and the challenges the community members faced in the execution of such a solution.



Specifications of the Withdrawal Well

The effective volume of the well is around 12,000 L. Recently, the performance of the withdrawal well was analyzed. This test was conducted by pumping out a majority of the water with the help of a 2 HP pump. It took roughly 20 minutes to pump out the water. Due to practical difficulties, unfortunately the volume of water could not be estimated in this test. Once the water was pumped to a dept of 20 feet, an automated data logging sensor was installed. This setup can then be utilized for understanding the recovery rate of the well. The meaning of the recovery rate of a well is the rate at which water rushes back into the well from the ground once space is made for it by pumping out the existing water.  The sensor's function was to log the water level of the well every 5 minutes. The sensor was kept for 2.5 days and no pumping was conducted during the time frame, Below is the results that were found in the duration.


To understand the graph, picture 0 being ground level and the y axis variables signifying the depth at which water was found below the ground level. Therefore, more the water in the well, closer is the surface to the ground. As it can be inferred, around 4 m of water was recovered during the span of the sensor being installed. That amounts to a volume of around 6,600 L! It can also be noticed that the majority of the recovery occurs in the first 24 hours. Zooming in on that portion of the data for analysis.


With this data, the initial recovery rate of the well can be calculated. In a span of 24 hours, the water level increases a column of about 3 m which gives a rate of 5833 L/day.

Water Quality

A water quality test was conducted previously, by sampling the water that was accessible from a private dewatering well which was constructed in order to cease the basement seepage problem that the resident was facing. In the below picture, the results of the test are given.


Through logical understanding, the water found in that well is from the same shallow aquifer. Therefore, we suspect the quality to be similar as well. One of the subsequent activities would be to conduct another water quality test for the water from the withdrawal well.

Pump Test

Another important activity that will be conducted is something known as a 'Pump Test'. This test would involve the monitoring of water levels while the pumping of the water occurs as well and data is collated for multiple days. This will allow us to further make more conclusions about the aquifer that will help fine tune the strategy and translate it into physical infrastructure to sustainably and effectively use the shallow aquifer. 

Monday, August 8, 2016

An Open Well as a source of water (Adarsh Palm Retreat near Devarabeesanahalli Lake)

Can Bengaluru work towards getting back to its openwells? This is the story of a community (Adarsh Palm Retreat near Devarabeesanahalli Lake) near a lake that is looking to use an open well as one of its sources of water. Do watch the video

Bengaluru (and other growing cities) are increasingly dependent on groundwater. In current time, borewells, are a very important source of water. Bengaluru now needs to manage its grounwater sustainably. While the city suffers from drying and dying borewells there are also pockets where water tables are shallow. We need to understand this and become stewards of our groundwater. And all of us need to be a part of this. Can we achieve this and in the process can we solve multiple problems of the city - water scarcity, flooding and pollution ? Can the actions of a gated community have a good positive externalities for the city. Can the city leverage private investment for larger public good? When this is coupled with good demand management and waste water management, are we helping the city solve its water prolems. Here is an example of a community that is trying to do just that - shifting from the deeper aquifer (borewells) to the shallow aquifer (open wells). Can the openwell become a metaphor for Bengaluru's path towards an enlightened water culture?


Can Bengaluru work towards getting back to its openwells? This is the story of a community (Adarsh Palm Retreat near Devarabeesanahalli Lake) near a lake that is looking to use an open well as one of its sources of water. Do watch the video Bengaluru (and other growing cities) are increasingly dependent on groundwater. In current time, borewells, are a very important source of water. Bengaluru now needs to manage its grounwater sustainably. While the city suffers from drying and dying borewells there are also pockets where water tables are shallow. We need to understand this and become stewards of our groundwater. And all of us need to be a part of this. Can we achieve this and in the process can we solve multiple problems of the city - water scarcity, flooding and pollution ? Can the actions of a gated community have a good positive externalities for the city. Can the city leverage private investment for larger public good? When this is coupled with good demand management and waste water management, are we helping the city solve its water prolems. Here is an example of a community that is trying to do just that - shifting from the deeper aquifer (borewells) to the shallow aquifer (open wells). Can the openwell become a metaphor for Bengaluru's path towards an enlightened water culture? - See more at: http://bangalore.citizenmatters.in/blogs/groundwater-stories/blog_posts/an-open-well-as-a-source-of-water-adarsh-palm-retreat-near-devarabeesanahalli-lake#sthash.MdMVDmFk.dpuf

Read more at: http://bangalore.citizenmatters.in/blogs/groundwater-stories/blog_posts/an-open-well-as-a-source-of-water-adarsh-palm-retreat-near-devarabeesanahalli-lake?utm_source=copy
Can Bengaluru work towards getting back to its openwells? This is the story of a community (Adarsh Palm Retreat near Devarabeesanahalli Lake) near a lake that is looking to use an open well as one of its sources of water. Do watch the video Bengaluru (and other growing cities) are increasingly dependent on groundwater. In current time, borewells, are a very important source of water. Bengaluru now needs to manage its grounwater sustainably. While the city suffers from drying and dying borewells there are also pockets where water tables are shallow. We need to understand this and become stewards of our groundwater. And all of us need to be a part of this. Can we achieve this and in the process can we solve multiple problems of the city - water scarcity, flooding and pollution ? Can the actions of a gated community have a good positive externalities for the city. Can the city leverage private investment for larger public good? When this is coupled with good demand management and waste water management, are we helping the city solve its water prolems. Here is an example of a community that is trying to do just that - shifting from the deeper aquifer (borewells) to the shallow aquifer (open wells). Can the openwell become a metaphor for Bengaluru's path towards an enlightened water culture? - See more at: http://bangalore.citizenmatters.in/blogs/groundwater-stories/blog_posts/an-open-well-as-a-source-of-water-adarsh-palm-retreat-near-devarabeesanahalli-lake#sthash.MdMVDmFk.dpuf

Read more at: http://bangalore.citizenmatters.in/blogs/groundwater-stories/blog_posts/an-open-well-as-a-source-of-water-adarsh-palm-retreat-near-devarabeesanahalli-lake?utm_source=copy

Friday, August 5, 2016

Talking Water Quality with Schools in Raichur


Grama Vikas had organized an awareness talk for various school headmasters and children. This was held at Raichur Govt Urdu School on the 30th July 2016. The agenda for the talk was to create awareness about the water quality and its implications on health. Mr S Vishwanath from the Biome Trust held the discussion on water quality. I joined with him to explain the audience about Fluorosis and its different manifestations. We emphasized on drinking safe water with better nutrition to mitigate the effects of Fluorosis.

Mr Vishwanath explaining about water quality.





Later there was a demonstration to test water quality for physical, chemical and bacteriological contamination using the field testing kit. Among which, there was focus on testing for Fluoride and bacteriological contamination in water. We explained the significance of the colour change upon adding the reagent and its corresponding Fluoride levels in water. Students were asked to check the color of the water and identify the fluoride levels. The Hydrogen Sulphide Test for bacteriological contamination was also demonstrated. Various methods to treat water at household level like chlorination and solar disinfection was discussed.

You can learn more about Fluoride Testing by following this link

At the end of the talk, Field Testing Kits were given to each school and asked to test water quality in their schools with the help of children. This was ensure that children inculcate the skills of water testing and create awareness about drinking safe water.

Later in the day, we visited an Environmental Park with Mr Afroz Pasha of the Swami Vivekananda Youth Movement, Raichur. 


The park is unique with the presence of different models for Toilets, Rainwater Harvesting and solid waste management. A walk within the park would help one in choosing the appropriate toilet (with quantity of materials used and their cost) best suited for one’s house. The park gives due importance to toilets and helps understand the relationship sanitation has with health. 

The pictures below show demos of different things in the park.





Overall it was good experience interacting with students, teachers , field officers and understanding their work.





Kiran Kumar Sen
Biome Environmental Trust
Fluoride Knowledge and Action Network