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With Bangalore water supply and sewerage board (BWSSB) failing to ‘cope up’ with the water demand of the growing city, lakhs of bore wells and tankers extracting water from the groundwater have led to over exploitation of the groundwater. However, there have been efforts from communities and individuals to sustainably manage the water within their fence. This is one such story of a private gated community in Bangalore

Situated in the south east of the city, the Rainbow Drive (RBD) is a private gated residential layout with an area of 34-acre and total of about 360

housing plots. As of now, 260 plots are

occupied. The layout gets absolutely no

formal water supply from BWSSB and is

completely dependent on its bore wells

as a water source. The site developer had

provided initial infrastructure including:

• Storm water drain network to carry

storm water out of the layout

• Six community yielding bore wells

• Two overhead tanks with piped

water supply connections to all plots

• Piped sewage connection to each

plot

• Two Sewage treatment plants

The plot owners’ associat ion

(POA) that took over the ownership

in 2004 manages the water supply

and sanitation. During the same time,

urbanization started to happen in the

neighborhood, making the POA realize

the intensity of water problems in the

near future.

The members observed that a lot

of reinvestment as well as measures

were needed to build the new water

and sanitation infrastructure and

upgrade the existing one. Therefore,

they did a complete research of the

water issues in the layout, collected

data about consumption, demand,

quantum of waste water generated

daily, issues of water quality, etc. to

get an understanding of the problems.

POA initiated some interventions like

creating a tariff policy, banning of bore

well water use for construction and

forbidding digging individual bore wells.

Water Management Initiatives:The result of this study was:

• Hydrogeologists were called for

who suggested that this space could

support 10-15 bore wells.

• The community bore wells left by

the builder had dried up and water

shortage was being experienced

• Houses had consumption meters at

the household level. And the tariff

was charged at flat Rs. 6/KL. The

study showed that this was minimal

Case Study:

Integrated urban water management

Benchmark of consumption No of households Percentage of households

Up to 135 LPCD 32 14%

Up to 246 LPCD (layout average) 130 59%

Greater than 246 LPCD 89 40%

Some houses were consuming more water than others

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and provided no incentive for the household to save water

• The billing cycle was two months which resulted in accumulated issues of faulty meters and/or demand.

• The most important result was that, the cost of water in the tariff scheme did not capture the cost required for treating the wastewater.

Sewage treatment plant was not adequate and the output water quality was not good enough.

During heavy rains upstream storm waters entered into the layout and caused significant flash flooding at the low end of the layout. This got mixed with the stagnating sewage and caused a lot of problems.

Lowering the demand From the study, it was evident

that 40% of the layout consumed more than the layout average. Two scenarios were looked at to address this. To keep the demand same @246 LPCD or reducing the demand to 150 LPCD. This required investing in rainwater harvesting (RWH) and recharge and gardening making use of treated wastewater. Also, a water

balance analysis was done considering

the future full occupancy.

The ana lys i s showed that

reducing the demand @150 LPCD

with all other water conservation

measures was most beneficial. The

analysis also showed that if effectively

implemented, the net recharge

would be more than the overall

withdrawal. Hence, it was made

mandatory for individual houses

to practice rainwater harvesting as

well as recharge. In addition, POA

invested in groundwater recharge in

the common areas.

Changing Pricing Policy

The bi-monthly bil l ing cycle

was changed to monthly so that

households would come to know

about the faulty meters soon and

fixing could be done immediately.

This also gave an opportunity to

the home owners to be aware of

their consumption with time for

adjustment. The POA moved from

flat rate @6/KL to a block tariff

system corresponding to the actual

production cost of the water. The first

tariff was developed according to the

new slabs:

The plot owners’ association of the Rainbow Drive engaged with Biome Environmental Solutions Pvt. Ltd. to develop rainwater harvesting strategies. Subsequently, with the support of Arghyam Foundation, they engaged in a monitoring exercise in the layout over approximately a year to understand the issues in more detail and evolve relevant solutions.

Consumption slab Tariff

Slab 1 (0-10KL) Rs. 10

Slab 2 (10-20KL) Rs. 15

Slab 3 (20-30KL) Rs. 25

Slab 4 (30-40KL) Rs. 40

Slab 5 (>40KL) Rs. 60

Wells in common stormwater drain invested by household (Individual investment)

Wells in common stormwater drain invested by POA (Collective investment)

Wells in individual house (individual investment)

Borewell water was being used for construction purposes

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In addition, homes investing in RWH and recharge were given a discount of `100. The tariff was revised in 2008, 2012, and 2014 is the latest revision to drive the residents towards recharge and control demand.

The current tariff is:

The water got expensive, almost equal to the tanker water costs at the highest slabs of consumption. The benchmark for what the “highest slab” has changed from 60 KL & above to 25 KL & above

Ban on private borewells and borewell water usage for construction

T h e r e c o m m e n d a t i o n o f hydrogeologist that 10-15 bore wells would be maximum that the layout can sustain led to discussions about

banning of private bore wells within the layout. Community bore well water remained available for domestic purposes. For construction purposes, water had to be sourced from outside at market rates.

Waste water infrastructure investment

The existing STP infrastructure was inadequate and was not treating the water effectively. The result that STP pumping was the single most contributor of the electricity bill, led to a search for new technology which would be of less maintenance and requires less energy. After searching many options, the POA narrowed down to Soil Biotechnology (SBT), and Phytorid. In October 2014, the Phytorid system of 250 KLD capacity became operational. The system receives ~100-150 KLD sewage daily and the treated wastewater is being used for gardening in common areas, gardening in the houses, and a small quantity of treated water is sold to a farmer in the adjacent plot.

Mandatory rainwater harvesting and recharge

Rea l i z i ng tha t the l a you t i s comp l e t e l y dependen t on groundwater, groundwater recharge was critical. RWH and recharge was made mandatory by the POA. As of now, there are in total 250 recharge wells in the individual houses as well as in the common areas (Storm water drain and open spaces).

Consumption slab Tariff

First 15,000 litres `30 per KL

15KL to 25 KL `50 per KL

Above 25 KL `120 per KL

Below graph shows the demand management timeline over a period:

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Impacts of the interventionsIncreased compliance with RWH

There seem to exist a correlation with tariff rates and the compliance with RWH and groundwater recharge. Moreover, the informed citizenry made aware about RWH and its importance led

the initiative. This probably is the highest

density of recharge wells in urban India.

Decreased per capita demand on community water supply

Though the occupancy has increased

over a period, total demand has come down

from 246 LPCD to 150 LPCD.

Increased savings from the STP

The Phytorid technology requires

minimal electricity as compared to the other

conventional sewage treatment plants. The

extent of reuse of this waste water for

gardening and consequent reduction in use

of fresh water for gardening is still being

studied. The POA is now closely monitoring

the quality of treated waste water – so

far it has conformed to KSPCB’s discharge

norms.

Going ahead:The reforms at Rainbow Drive started

in 2004 by efforts of conscious residents of

the layout. The interventions that started

with 20 recharge wells now have reached

to 250. The relationship between shallow

groundwater recharge and the bore well

yields (if any) needs more exploration but,

the demand management with recharge

compliance has worked till now.

Courtesy: Biome Environmental Trust & Rainbow

Drive POA