02 WDHC V White APHW Seoul Loss of Resilience in Water Supply

APHW 6 Seoul 19-21 Aug 2013

Loss of Resilience in Water Supply in Atolls in the

Maldives Following the 2004 TsunamiIan White

Fenner School of Environment & SocietyTony Falkland

Island Hydrology ServicesRashid Mhd Bari

Development Technologies Male’Atlas of the Maldives


Key Message

Short term, major disaster relief responses can lead to long-term, broad-scale, loss of resilience in water supply if local hydrology, local experience, and capacity are not taken into account and monitoring is not continuedIsdhoo Laamu atoll


Outline

Overview MaldivesClimateWater SourcesImpacts of 2004 TsunamiDisaster ResponsesConsequences – loss of resilienceSteps to increase resilienceConclusions

Male’ Capital of Maldives

Study focuses on rural, non-resort outer islands


Maldives

870 km

Population ~350,000Urban 40%Growth rate 1.8 %

Urban growth rate ~ 4.2 %

26 AtollsHighest elevation ~ 2.4m ASL

Land area ~ 300 km2

>1,100 islands~ 200 inhabited~ 200 resort~ 600 ‘agricultural’

Principal industries: TourismTuna Fishing

Dispersed population 2/3 ruralAtlas of the Maldives


ClimateTwo monsoons NE, SW

Average Annual Temp ~ 28°

C

Av. Ann Rainfall DistributionNORTH1800 mm (CV 0.16)Dry season Dec -

MarSOUTH2320 mm (CV 0.15)Dry season Feb -

Mar

Jan –

Mar

Dry

May –

Nov

Wet

Atlas of the Maldives


Trends in Rainfall

Annual Decrease

5 mm/y

Wet Season Decrease

4 mm/y

Southern-most Met. Station S. Gan


Trends in Indian Ocean Dipole Moment Index


Atoll Water ResourcesShallow, thin fresh groundwater lens underlain by brackish water as the lens mixes with seawater

below. Aquifer is highly permeable & lens easily polluted

particularly with sewage

Ocean Lagoon

Seawater

Brackish water zone

Freshwater zone


Rural Water Sources pre-2004

Wet SeasonHousehold rain tanksDrinking & Cooking

Shallow household wellsAll other uses

Dry SeasonCommunity rain tanks

Shallow Household & Community wells


Urban Water Sources pre-2004

Wet

&

Dry

SeasonsSeawater Desalination very successfully operated since 1988

Over-extraction of groundwater plus pollution with sewage and other contaminants has exhausted the freshwater lens in Male’


Groundwater Use Pre-2004

About 75% of inhabited islands were drinking untreated groundwater for some part of the year prior to 2004 Tsunami

Characteristic (1999) No.Total no. of islands 202Total islands with fresh GW 132Total islands with salty GW 17Total islands drinking GW all the time 15Total islands drinking GW when no rainwater 146Total no. of Wells 38,476Average depth of well below ground surface(m) 1.6±0.5Average no. Pers/well 5.2No. people drinking GW all the time 32,300No. people drinking GW some of the time 104,975No. of people drinking untreated GW 95,815Estimated total annual GW use (m3/y) 10,269,637


2004 Indian Ocean Tsunami

26 December 2004


Maldives Tsunami Impacts• 88 dead

• ~ 80 inhabited islands overtopped

• Seawater intrusion in all freshwater lenses

• Severe pollution of groundwater from sewage, petroleum products and other sources

• Destruction of rain tanks

• Communities from most damaged villages relocated to other islands

Atla

s of

the

Mal

dive

s


Groundwater Impacts

Extensive immediate post-tsunami GW testing showed:Overtopping – salinising freshwater lensPathogenic contamination from septic tanks, soakaways and pit latrinesChemical contamination from petroleum stores

Warning that groundwater in all islands was unfit to drinkNo systematic wide-spread GW monitoring post-tsunamiIn effect, the warning is still in place


Donor Response to Disaster

2.5 m3 rain tank for every household in MaldivesIsland community rain tanks52 desalination plants, total capacity: 3,260 m3/d32 sewerage systems with 15 sewerage treatment systems

Focussed on WATSAN for outer islands


Outer Island Statistics in 2013Average outer island HH rain tank capacity 1.1→2.9 m3

Total community tank capacity 13,800→17,200 m3

Only 40% desalination plants still operational, (1,410 m3/d), in 20% capacity >10 L/pers/dOnly 30% of sewerage systems operationalOnly 6% of sewerage treatment plants operational


Net Result: Regular Dry Season “Emergencies”

0

1,000

2,000

3,000

4,000

5,000

6,000

7,000

8,000

2005 2006 2007 2008 2009 2010 2011 2012Year

Tota

l vol

ume

of w

ater

sup

plie

d (k

L)

No data available for 2010: water supplied by Provincial

offices

50% of outer islands request desalinated water from Male’ every year in dry season


Why the loss in outer island resilience?

Groundwater officially abandoned as water source (no monitoring)HH rain tank capacity too smallLocal desalination plants too expensive and too technical to operateSewerage systems and treatment plants too expensive and too technical to operateGeneral governance failure


Potential for Groundwater Use

K. Thanburudhoo Atlas of Maldives

To realise estimated GW potential requires:

• Detailed assessment and monitoring

• Appropriate land use planning and groundwater protection

• Appropriate extraction technology (skimming wells)

• Appropriate sanitation systems

Charateristic ValueTotal no. of inhabited islands 202Total Area (km2) 127No of islands with fresh GW (1999) 132No of islands with useable GW (2013) 77Area of potential sources (km2) 80.3Estimated sustainable yield (m3/d) 52,400Per Capita Atoll supply (L/pers/d) 182


Size of Rain tanks NeededMust take into account the rainfall distribution from North to South and the space available for rain tank installation


Sanitation Systems

Male’ the capital of the Maldives, with a current population of > 100,000 has been discharging untreated sewerage at depth from 6 outfalls into the deep sea since 1988.

The impacts appear minimal but a study is required to determine if this approach can be used in other, similarly located atolls.


Re-establishing Atoll ResilienceLh. Hudhifushi Atlas of Maldives

• Improve water governance recognising the diverse and dispersed nature of Maldives communities

• Introduce land use planning, recognising and protecting GW as a vital resource

• Assess island GW resources and re-introduce monitoring

• Increase household and community rainwater storage

• Use atoll-specific groundwater extraction and sanitation technology

• Strengthen island capacities in integrated water resource and sanitation operation and management


Conclusions

Sh. Komandhoo Google Earth

• Major disaster relief responses in the Maldives following the 2004 “Boxing Day” tsunami were successful in the short-term

• In the long-term they have resulted in a broad-scale loss of atoll and outer island community resilience in water supply

• The response did not take into account local hydrologic conditions, local experience in sanitation and local capacity and failed to recognise the importance of continued monitoring

This study was supported in part by the World Bank

02 WDHC V White APHW Seoul Loss of Resilience in Water Supply

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