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Sri Lanka Rainwater Harvesting
1. Sri Lanka
Sri Lanka
Rainwater harvesting
Rainwater harvesting
Why Sri Lanka should concentrate on
Why Sri Lanka should concentrate on
Rainwater Harvesting
Rainwater Harvesting
I.DISSANAYAKE
SRI LANKA
2.
3.
4. Introduction
Introduction
ƒ
ƒ Definition
Definition
ƒ
ƒ Rainwater harvesting (RWH) is the capture and
Rainwater harvesting (RWH) is the capture and
storage of rainwater for purposes such as potable
storage of rainwater for purposes such as potable
and non potable uses, storm water abatement and
and non potable uses, storm water abatement and
landscape irrigation. It is a strategic tool and
landscape irrigation. It is a strategic tool and
proactive approach for drought mitigation and
proactive approach for drought mitigation and
alleviate water scarcity.
alleviate water scarcity.
5. ƒ
ƒ Roof rainwater collection means getting clean
Roof rainwater collection means getting clean
water just from out side the door step.
water just from out side the door step.
ƒ
ƒ It
It’
’s method is simpler, reduces fetching time,
s method is simpler, reduces fetching time,
economical, no toxic, no fluoride, minimize
economical, no toxic, no fluoride, minimize
health risk.
health risk.
ƒ
ƒ Harvested rainwater can be particularly useful
Harvested rainwater can be particularly useful
when no other sources of water supply is
when no other sources of water supply is
available ,or if the available water supply is
available ,or if the available water supply is
inadequate or poor quality.
inadequate or poor quality.
6. Historical perspective
Historical perspective
ƒ
ƒ Traditionally and Historically evolved methods of
Traditionally and Historically evolved methods of
RWH
RWH
ƒ
ƒ The Great king
The Great king Parakramabahu
Parakramabahu –
–
Parakramabahu
Parakramabahu (1153
(1153 -
- 1186 A.D.) during
1186 A.D.) during
Polonnaruwa
Polonnaruwa kingdom.
kingdom. “
“Not a single drop of water
Not a single drop of water
received from rain should be allowed to escape in to the sea
received from rain should be allowed to escape in to the sea
without being utilized for the benefit of human kind.
without being utilized for the benefit of human kind.”
”
Sigiriya
Sigiriya Rock fortress
Rock fortress.
. In the 5th century, the
In the 5th century, the
construction of
construction of Sigiriya
Sigiriya rock fortress by the king
rock fortress by the king Kasyapa
Kasyapa was
was
the unique and magnificent showpiece with storage tanks and
the unique and magnificent showpiece with storage tanks and
swimming pools
swimming pools etc.to
etc.to present as rain water collection model.
present as rain water collection model.
7. Water scarcity and or stress
Water scarcity and or stress
inadequacy of water supply to match the
inadequacy of water supply to match the
demand
demand
-
-There are four main underlying causes
There are four main underlying causes
1. Population increase and demand for Public
1. Population increase and demand for Public
amenities
amenities
-
- Land clearing and reclamation
Land clearing and reclamation
-
- destruction to water bodies:
destruction to water bodies:
-
- siltation affect to water sources,
siltation affect to water sources,
-
- high demand for potable water and
high demand for potable water and
sanitation.
sanitation.
8. Water scarcity and or stress
Water scarcity and or stress
inadequacy of water supply to match the
inadequacy of water supply to match the
demand
demand
2. Urbanization and new townships
2. Urbanization and new townships
-
- Construction of new infrastructure,
Construction of new infrastructure,
new
new condominiums
condominiums
-
- demand for pipe borne water and
demand for pipe borne water and
sanitation.
sanitation.
9. Water scarcity/stress
Water scarcity/stress
inadequacy of water supply to match the
inadequacy of water supply to match the
demand
demand
3. Stress on pipe borne water supply
3. Stress on pipe borne water supply
(infrastructure and financial limitations).
(infrastructure and financial limitations).
new water supply schemes,
new water supply schemes,
water supply infrastructure
water supply infrastructure
costly maintenance
costly maintenance
10. Water scarcity and or stress
Water scarcity and or stress
inadequacy of water supply to match the
inadequacy of water supply to match the
demand
demand
4. Pipe borne water wastage
4. Pipe borne water wastage
-
- Flushing,
Flushing,
-
- Washing and gardening.
Washing and gardening.
-
- public water wastage
public water wastage
-
- water theft
water theft
11. Water scarcity/stress
Water scarcity/stress
inadequacy of water supply to match the
inadequacy of water supply to match the
demand
demand
Direct causes
Direct causes
ƒ
ƒ Surface water contamination
Surface water contamination
-
- Natural reasons such as pollution, chemical and
Natural reasons such as pollution, chemical and
negligence
negligence
-
- Agriculture waste Agro chemicals, nutrient
Agriculture waste Agro chemicals, nutrient
-
- Discharging effluent by industries
Discharging effluent by industries
-
- Dumping of Solid waste by local authorities and
Dumping of Solid waste by local authorities and
individuals
individuals
ƒ
ƒ Natural phenomena
Natural phenomena
-
-Geography, Geology naturally sloppy areas non
Geography, Geology naturally sloppy areas non
availability of water
availability of water
-
-Seasonal cycles such as Drought
Seasonal cycles such as Drought
-
-Disasters like earth slips .
Disasters like earth slips .
12. Water scarcity/stress
Water scarcity/stress
inadequacy of water supply to match the
inadequacy of water supply to match the
demand
demand
ƒ
ƒ Ground water resources depletion.
Ground water resources depletion.
-
- Water extraction for agriculture, Shrimp
Water extraction for agriculture, Shrimp
farms, domestic uses
farms, domestic uses
-
- Contamination due to salination,
Contamination due to salination,
Chemical and toxic substances
Chemical and toxic substances
-
- Less seepage /ground absorption due to
Less seepage /ground absorption due to
concrete canals and drainage
concrete canals and drainage
-
- Mining for sand, quarry, gem or other minerals
Mining for sand, quarry, gem or other minerals
13.
14.
15.
16.
17. 1961
1961-
-90 Annual
90 Annual
Average
Average 2001
2001 2002
2002 2003
2003 2004
2004 2005
2005 2006
2006
Rainfa
Rainfa
ll
ll
mm
mm
No of
No of
Rainy
Rainy
days
days
Rainfal
Rainfal
l
l
mm
mm
No of
No of
Rainy
Rainy
days
days
Rainfal
Rainfal
l
l
mm
mm
No of
No of
Rainy
Rainy
days
days
Rainfal
Rainfal
l
l
mm
mm
No of
No of
Rainy
Rainy
days
days
Rainf
Rainf
all
all
mm
mm
No of
No of
Rainy
Rainy
days
days
Rainf
Rainf
all
all
mm
mm
No of
No of
Rainy
Rainy
days
days
Rainfal
Rainfal
l
l
mm
mm
No of
No of
Rainy
Rainy
days
days
Anuradhapura
Anuradhapura
Bandarawela
Bandarawela
Colombo
Colombo
Hambantota
Hambantota
Kandy
Kandy
NuwaraEliya
NuwaraEliya
Ratnapura
Ratnapura
Trincomalee
Trincomalee
1285
1285
1572
1572
2424
2424
1050
1050
1840
1840
1905
1905
3749
3749
1580
1580
89
89
129
129
146
146
87
87
148
148
163
163
205
205
86
86
1262
1262
1539
1539
1933
1933
730
730
1922
1922
1681
1681
3264
3264
1431
1431
104
104
146
146
132
132
75
75
164
164
189
189
205
205
103
103
1260
1260
1602
1602
2100
2100
982
982
1927
1927
1517
1517
3202
3202
1725
1725
99
99
147
147
174
174
95
95
171
171
186
186
215
215
83
83
1192
1192
1498
1498
2030
2030
1273
1273
1502
1502
1374
1374
4021
4021
1425
1425
97
97
136
136
158
158
97
97
158
158
170
170
209
209
97
97
1444
1444
1591
1591
1958
1958
1165
1165
1565
1565
1741
1741
3742
3742
1926
1926
114
114
154
154
162
162
104
104
168
168
206
206
229
229
118
118
799
799
1516
1516
2814
2814
978
978
1784
1784
1347
1347
3405
3405
1792
1792
87
87
155
155
163
163
82
82
179
179
188
188
211
211
87
87
1324
1324
2081
2081
2723
2723
1334
1334
2121
2121
2555
2555
3736
3736
78
78
93
93
177
177
173
173
133
133
188
188
219
219
243
243
15
15
Met. stations
Met. stations
Rainwater Potential
Rainwater Potential
RAINWATER AVAILABILITY
RAINWATER AVAILABILITY
Annual rain fall and rainy days
Annual rain fall and rainy days
Source: Central Bank reports
19. Benefits from rainwater
Benefits from rainwater
ƒ
ƒ Reduce water stress
Reduce water stress to the people who practice RWH
to the people who practice RWH
ƒ
ƒ Time
Time saving from fetching of water
saving from fetching of water
ƒ
ƒ Health
Health-
- reduce water contamination
reduce water contamination
ƒ
ƒ Cost of water
Cost of water-
- No or less: water bills, water
No or less: water bills, water bowser
bowser cost,
cost,
transport expenses
transport expenses.
.
ƒ
ƒ Living condition
Living condition improvement by
improvement by labour
labour
time saving and water for better sanitation
time saving and water for better sanitation
ƒ
ƒ Support to environment
Support to environment water replenishment
water replenishment
ƒ
ƒ Reduce stress
Reduce stress to govt. by reducing heavy investment on
to govt. by reducing heavy investment on
infrastructure and it
infrastructure and it’
’s maintenances.
s maintenances.
21. Measures to be considered for future
Measures to be considered for future
ƒ
ƒ -
-Integrated approach
Integrated approach –
–Public, NGOO, CBOO,
Public, NGOO, CBOO, Govt
Govt, institutions,
, institutions,
local authorities and village level other organizations.
local authorities and village level other organizations.
ƒ
ƒ -
-Government patronage.
Government patronage.-
- Concessions, subsidies, Tax rebates,
Concessions, subsidies, Tax rebates, govt
govt
sponsored funding arrangements such as matching grants.
sponsored funding arrangements such as matching grants.
ƒ
ƒ -
-Develop mechanism based on policy
Develop mechanism based on policy-
-. individual Activity based
. individual Activity based
work
work programme
programme
ƒ
ƒ -
-New schemes for implementation
New schemes for implementation -
- Public private partnership
Public private partnership
programmes
programmes
ƒ
ƒ -
-Reduce misconceptions among people
Reduce misconceptions among people-
-Measure to improve
Measure to improve
rainwater quality for people to believe value of rainwater
rainwater quality for people to believe value of rainwater
ƒ
ƒ -
-Show benefits
Show benefits-
- improvement to livelihood, economic benefits,
improvement to livelihood, economic benefits,
improve sanitation.
improve sanitation.
ƒ
ƒ -
-Creation of Awareness
Creation of Awareness –
–Different types of awareness
Different types of awareness programmes
programmes
ƒ
ƒ -
-Make Legal /mandatory requirement
Make Legal /mandatory requirement –
–Such as Chennai/
Such as Chennai/
bangalore
bangalore India, selected cities in Japan ,Texas USA,
India, selected cities in Japan ,Texas USA,
22. Future interventions
Future interventions
Issues
Issues Programme
Programme Activities
Activities Benefits
Benefits
No policy
No policy
interventions
interventions
Non availability of
Non availability of
integrated
integrated
approach
approach
Lack of
Lack of
arrangement for
arrangement for
water quality
water quality
checking
checking
Lack of awareness
Lack of awareness
and education
and education
programme
programme
Policy based development
Policy based development
approach
approach
Introduce legislative
Introduce legislative
support: flood
support: flood
mitigation, Building and
mitigation, Building and
apartment construction
apartment construction
approval with (COC)
approval with (COC)
Road development;
Road development;
NWSDB by laws
NWSDB by laws
development
development
Stormwater
Stormwater control,
control,
Reduction in Cost to
Reduction in Cost to govt
govt
for water infrastructure
for water infrastructure
Water security and
Water security and
confidence in
confidence in
water availability
water availability
Integrated approach for
Integrated approach for
development
development
Public participation,
Public participation,
Govt
Govt patronage and
patronage and
support; NGOO
support; NGOO
involvement; village level
involvement; village level
community group
community group
involvement; identify
involvement; identify
role of the individual
role of the individual
group
group
Collective effort; cost
Collective effort; cost
reduction; establish
reduction; establish
equity; fulfilling actual
equity; fulfilling actual
requirements; reduce
requirements; reduce
misconceptions.
misconceptions.
Scientific approach
Scientific approach Water quality checking
Water quality checking
at intervals; Involve
at intervals; Involve
relevant agencies for
relevant agencies for
advises and field work
advises and field work
coordination.
coordination.
Get confidence on water
Get confidence on water
quality; development of
quality; development of
proper mechanism for
proper mechanism for
field
field programmes
programmes; Better
; Better
coordination with
coordination with
relevant groups
relevant groups
Awareness and education
Awareness and education
programmes
programmes
Schools, temples and
Schools, temples and
larger institutions based
larger institutions based
programmes
programmes for
for
implementation.
implementation.
Creation of awareweness
Creation of awareweness
among relevant groups
among relevant groups
and reduce
and reduce
misconceptions and
misconceptions and
popularize RWH
popularize RWH
23. Future interventions
Future interventions
Need for
Need for
demonstratio
demonstratio
n tank
n tank
construction
construction
programmes
programmes
Demonstration effect
Demonstration effect
Sponsored
Sponsored
activities;
activities;
demonstration
demonstration
tanks
tanks
construction
construction
Encourage people ;create tendency to
Encourage people ;create tendency to
have and own tank and popularize
have and own tank and popularize
tank construction.
tank construction.
Assessment
Assessment
for incentives
for incentives
No institution
No institution
interested in
interested in
RWH
RWH
Concessions and
Concessions and
incentives
incentives
Tax rebates ,tax
Tax rebates ,tax
incentives;
incentives;
grants or
grants or
matching
matching
grants;
grants;
material
material
supply.
supply.
Cost reduction in tank construction,
Cost reduction in tank construction,
more demand for water harvesting.
more demand for water harvesting.
Institutional
Institutional
arrangements for
arrangements for
RWH. Higher level
RWH. Higher level
commitment.
commitment.
Study
Study
infrastructure
infrastructure
requirements
requirements
Benefit to the water authorities;
Benefit to the water authorities;
reduction of monthly water expenses
reduction of monthly water expenses
to the institution
to the institution