It is estimated that 40 per cent of the population of Bangalore is dependent on groundwater, whereas the remaining part is pumped from the Cauvery river through a distance of 95 kilometres and a head of 1000 metres.

Bangalore receives 970 mm rainfall annually and the number of rainy days is 59.8. Highest amount of rainfall is received during April to November, while the rest of the months receive scanty rainfall. Peak runoff is 50 millimeters per hour. Due to the availability of rainwater throughout the year, water is basically stored in these rainwater harvesting systems and used for non-potable purposes. Water from the rooftops is led into storage structures. First flushing is normally done by providing an extra length of pipe to collect the polluted 2.5 mm of rainfall. Filters are made of sponge and a mixture of sand, gravel and charcoal. After first flushing and filtration water is led into under ground sumps (which are very common in Bangalore) or to a new storage tank.

click here

The overflow from this tank is taken to an open well to recharge the aquifer.The geological formations are predominantly granite and granitic gneiss, with joints and fractures in abundance due to intense chemical weathering of rocks. The depth of weathering varies from 0.2 m to 20 m. This geological set-up offers an immense scope for recharging of ground aquifers.

The undulating terrain with gentle slopes draining into lakes offer an ideal situation for water harvesting. In the urban area of Bangalore waterbodies cover about 5 per cent of land.

Potential of rainwater harvesting

Name of City
Proposed area for 2011(category and area in Sq km)
Annual water harvesting potential in billion litres
100 per cent harvesting
50 per cent harvesting
Bangalore Development area 597.0 579.10 289.55
Green Belt 682.0 661.54 330.77
Total area 1279 1240.64 620.32

Notes: Average annual Rainfall = In mm 970; Annual demand-supply gap 49.28 billion litres
Case studies:

The project:
The industrial unit of a 20 hectare

Breakup of the area:
Rooftop area: 29,961 Sq. m
Paved area : 43,095.66 Sq.m
Unpaved area : 129,286.98 Sq.m
The total rainwater harvesting potential of the site is 185 million litres.

A pilot project was set up in May 2000 covering about 1, 280 sq.m of roof area for the administrative block and the canteen building. With storage capacity of 42,00 litres, the unit collects about 1.05 million litres per year. The system is expected to pay back for itself in five years.



Community of Practice on Arsenic Contamination

Community of Practice on Arsenic Contamination

The context

Water quality concerns are immensely important from human health and ecological perspective. Recent literature on water quality issues clearly establishes that in India, some of the levels of contaminations have reached or even passed the critical stage. It also reveals that while increasing access to water is crucial, doing so without addressing quality issues may prove to be a futile exercise. Indeed, as per study conducted by Goldman Sachs to India, in order to accelerate its growth and reach its full economic potential, environmental protection with environmental sustainability of water and energy needs to become one of the top 10 interventions in the country (Goldman Sachs 2008). Based on the recent data on the percentage of habitations affected, Figure 1.1 shows top five states in the country that are most affected by water quality. Other pollutants include mercury, uranium, etc., which are leached into the water bodies due to excessive mining in many regions of the country.

Figure 1.1: Top Five Water Quality Affected States in India

Source: Data from DDWS, April 2011

Although the Indian government is working proactively on the increasing threat of water pollution, it will take far more than political will for these actions to translate into concrete measures resulting in improved water quality. Within the whole debate on water quality, chemical pollutions such as nitrate, fluoride and arsenic need special mention because they are closely associated with the level of groundwater use and lack of regulation.

Understanding the state of knowledge on Arsenic Contamination in India?

The desirable limit of arsenic in water according to Indian standards is 0.01 mg/l, while the permissible limit in the absence of an alternate source is 0.05 mg/l. Skin conditions such as increased pigmentation and decrease in normal pigmentation, peripheral neuropathy, skin cancer, bladder and lung cancers, and peripheral vascular disease are observed in populations ingesting arsenic-contaminated drinking water (WHO 2011). Since the first case of groundwater arsenic contamination was reported in the year 1983, from 33 affected villages in four districts in West Bengal, the number of affected villages has increased to 3,417 in 111 blocks in nine districts in West Bengal alone (Ghosh and Singh, 2009).1 In a joint study conducted by the Indian Institute of Technology (IIT), Guwahati, and Public Health Engineering Department (PHED), Assam, 8 per cent of the samples were found to be above the BIS permissible level and 30 per cent were above the WHO permissible limit thus exposing about 0.7 million people to contamination (Borah, 2011). The top five arsenic affected states in terms of percentage of habitations affected as on 1 April 2011 are Assam (2.4% of habitation affected), West Bengal (1.83% of habitation affected), Bihar (1.03% of habitation affected), UP and Karnataka (0.12% and 0.07% habitation affected).

Arsenic contamination in Bangladesh, Nepal and Pakistan

Apart from the arsenic contamination which has been reported in India, large population also exist in Bangladesh and tarai region of Nepal. Rough estimates suggest that about 122 million populations in 64 districts of Bangladesh are affected by arsenic.2 In Nepal, the inhabitants in Terai region is largely affected. The National Sanitation Steering Committee (NSSC), with the help of many other organizations, has completed arsenic blanket test in 25 districts of Nepal by analysing 737,009 groundwater samples. 23% of the samples were containing 10–50 µg/L of As, and the 8% of the samples were containing more than 50 µg/L of As. Recent status of over 737,009 samples tested, the 7.9% and 2.3% were contaminated by 10–50 µg/L and >50 µg/L, respectively of As (Thakur et al, 2011). In Pakistan, arsenic is reported in Punjab and Sindh regions. It is estimated that in Punjab, 18 districts out of 34 have arsenic contamination in both shallow and deep water sources. A recent study shows that out of 2.36,000 samples in Punjab – 31% contain 10-50 μg/L, while 9.0% had As over 50 μg/L. Maximum contaminated samples of 250-500 μg/L found in southern and eastern Punjab. Also, serious arsenic contamination over 1000 μg/L has also been found in two central districts in Sindh.3

The Problem

Number of times key stakeholders at various events, have called for a broad community of practice on Arsenic Contamination that will link arsenic contamination with groundwater development and management issues and link practitioners, policymakers, academia in substantive issues and challenges that confront this sub-sector. Despite the plethora of networks and thematic working groups on various issues related to arsenic contamination, there has been a persistent gap in translating academic findings into actionable items. There are issues of socio-economic exclusions where discourse on arsenic largely remained techno centric without appropriate inclusion of the voices of the poor and the vulnerable population. The research, seminars, workshops, analysis of problems, prioritizing and decision-making for mitigation of the arsenic problem – are far from the reach of the affected communities. Many a time, primary stakeholders, are not even aware of the disaster. They know very little about the long- and short-term impact of arsenic on their lives and livelihoods. Governments all across the subcontinent are seen to be opting for a fire fighting approach- reacting to the situation with short term solutions without proper understanding of the local context.

Considerable gap exists in cross regional learning and linking of success stories into country specific arsenic policies and strategies. For instance, Bangladesh and India have received greatest attention in terms of groundwater testing, maintaining the data bank on arsenic distribution in the aquifers and formulating effective policy framework than any other countries in south Asia. In fact Bangladesh is one country that has come up with national arsenic policy (March 2004) and have developed a detailed plan of action. Compared to this Nepal is at the nascent stage of tackling this known problem while Pakistan is only now discovering that such problem exists there, particularly in the Indus basin.

At this critical juncture, it has been increasingly realized that if we are to meet future challenges with effective solutions and sufficient levels of preparedness, it is imperative to have a pan India/South Asia understanding of these issues and develop more coordinated responses. Developing effective platform for information sharing amongst the arsenic affected countries of South Asia with a purpose of coordinated action towards arsenic mitigation is thereby imperative. In addition to filling knowledge gaps and facilitating information exchange and debate, the platform is envisaged as an inclusive space for practitioners oriented towards change and more importantly for the affected citizens to voice their concerns.

The analysis made by individuals and organisations working on Arsenic issues across south Asia shows that currently, there are a very few exiting networks that address the issue in a comprehensive way. Few qualified organisations or networks with their localised mandate and limited outreach are in existence currently and although thematic or regional focus is their strength they are limited or constrained in terms of providing opportunity for successes to be disseminated widely and ideas to be challenged. It won’t be an exaggeration to say that currently, the gaps in the knowledge and efforts in addressing the issue manifest in lack of collaboration, duplication of efforts and competition leading to conflicting messages at the county level. These are at best, inefficient and, at worst, detrimental to the collective goal of improving status of arsenic affected people. Therefore there is certainly, a pressing need for larger learning alliances and groups with an explicit focus on arsenic. There is a need for; consultations with numerous sector practitioners and professionals to identify several gaps in knowledge, collaboration with practitioners at all levels seeking the opportunities for frank dialogue and debate resulting into, collaborative learning though exchanging problems and solutions with peers. Such an effort can lead to improving the learning curve and uptake of knowledge, identifying best practices, translating research to practice, greater visibility of who is working on what and very importantly linking of the grassroot level concerns over arsenic to the top & channelizing the solutions and knowledge to the grassroot level. In response to these identified needs the community of practice for arsenic contamination seeks to address two problems:

  • There is poor uptake of learning and best practices specifically between national and international levels and cross regionally.

  • There is presently no national platform for open exchange and frank debate across thematic areas and on controversial issues and between professionals representing different views and interests.


Borah, H.K. 2011. ‘Drinking Water Scenario in Assam’, India Water Development Report Multistakeholder Consultation Workshop, Indian Institute of Technology (IIT), Guwahati, Assam.

Central Pollution Control Board (CPCB). 2008. ‘Status of Water Quality in India- 2007: Executive Summary’,

Department of Drinking Water Supply (DDWS). 2011. Compiled from the online data of National Rural Drinking Water Programme. See

Ghosh, N.C. and R.D. Singh. 2009. Ground Water Arsenic Contamination in India: Vulnerability and Scope of Remedy’, 5th Asian Regional Conference of ICID, 9-11 December 2009, New Delhi Available at: [accessed on October 16, 2012].

Goldman Sachs. 2008. ‘Ten Things for India to Achieve its 2050 Potential’, Global Economics Paper No. 169. Available at: [accessed on: October 16, 2012].

Thakur, Jay Krishna, Rinku Kumari Thakur , AL Ramanathan Manish Kumar  and Sudhir Kumar Singh. 2011. Arsenic Contamination of Groundwater in Nepal—An Overview. Water 2011, 3(1), 1-20.

WHO. 2011. Guidelines for Drinking Water Quality, 4th Edition. Geneva: WHO.


Dug Wells

Dugwells – Lessons learnt


  • Wells sourcing from Deep Aquifer are usually potable (beyond 30 mtr)
  • Space availability for digging well
  • Skilled labour availability for construction of well
  • Should be in an open / clear space (no contamination from leaf litter / bird dropping)
  • Natural filter media should be ensured at the bottom / sidewalls
  • No contamination points like toilets, garbage pits, drainage line etc, near to well

Reasons for success

  • Easy access to dugwells (in terms of distance and caste barriers)-
  • Plastering and whitewash of the inner walls of dugwells reduced algal growth
  • Use of Neem leaves / Jamun leaves acts as dis-infectant
  • Dugwells built around the homogeneous community helps in maintenance and better access-
  • Cemented platform and proper drainage of excess water while drawing of water, needs to be ensured
  • Community participation in deciding the location, design and execution is needed. Cash or labour contribution is also needed for bringing ownership.

Reasons for Failure

  • Village dynamics can lead to access barrier to few people in the village
  • As in the past, the introduction of new technologies leads to defunctional & abondoning of wells (MPA, SSUD)
  • Due to permeable layer at the bottom, few dugwells get murkier. Also due to improper lining, the wells also cave in.
  • Due to open space and common ownership, scope for contamination are higher




Concern Area




Cost Economics

The cost of digging new wells costs ranges from Rs. 126000 (in case of MPA) and Rs. 100000 (in case of ASA). The cost of renovation of well costs around Rs. 25000 in both cases.