Integrated Urban Water Resources

Management in Sri Lanka

Background, Issues and Training

Needs

N.T.S. WIJESEKERA

Department of Civil Engineering

University of Moratuwa,

Moratuwa, Sri Lanka

The Democratic Socialist

Republic of Sri Lanka

An Island in the Indian Ocean

surrounded by tropical

beaches

Latitude 5'55" - 9'51" &

Longitude 79'42" - 81'52".

Total land area is 65,610 sq. km

870 sq km of inland water

(1.3% of total)

Length-445 km Breadth- 225 km

SRI LANKA

Population of Sri Lanka is about 20 million

Density is highest in the southwest : Colombo

74% of the population are concentrated in

the southwest

The net population growth is about 1.2%.

21.5% Live in Designated Urban Areas

In Colombo and

Suburbs

Impervious Area is

varying around 25

– 40% in

residential areas

In commercial area

this is

approximately 95%

Colombo

Galle

Kandy

Major Urban Centers

Jaffna

Anuradhapura

Trincomalee

Negombo Kurunegala

Matara

Other Urban Centers

Jaffna

Anuradhapura

Trincomalee

Negombo Kurunegala

Matara

Close to Water

Bodies

Lake

Ocean

Colombo

Galle

Kandy

River Delta,

Habour,

Low Lying,

Land

Filling,

Water

Intakes,

Drainage

75% Urban and 14% Rural are served with

Pipe Borne Water

Demand for safe water increases by 8-10%

each year

Most urban water supply schemes do not

have the capability for 24 hr service

The Water Supply Sector Expenditure

0%

10%

20%

30%

40%

50%

1993

1994

1995

1996

1997

1998

1999

2000

2001

2002

2003

Getting Reduced

Water Sector Issues in the Urban Areas

of Sri Lanka

• Urban Water Supply and Sanitation

• Urban Area Flooding

• Quality of Water Bodies

Urban Water Supply

Sources: Mostly,- Surface Water Several, - Groundwater

Colombo – Surface water from Kelani and Kalu Rivers

Kandy – Mahaweli River

Galle – Gin River

Water is pumped from Rivers to storage reservoirs and replenished

Water availability is the availability of river flow: In the Dry Season Salt

water intrusion: (Elevation increase of Kelani and Gin Barrages)

Storage Reservoirs have limited Capacity and no expansions

have been done in the recent past

Groundwater is pumped from deep aquifers. Wells are designed

accordingly but the monitoring of the aquifer status other than

the quality of water is not done during extraction (in any of the

schemes)

Demand for Domestic and Industrial Uses are calculated based

on Daily Demand and the availability of sufficient storage until

replenished

Mid Night Noon 6 PM

Training Needs:

• Hydrological Assessment of the Source Watersheds

and Data Collection Needs

• Source Area Engineering and Management

• Basin Planning with adequate inputs from other

sectors to identify the availability for expansions

• System study techniques to identify alternative

solutions (to incorporate supplementary storage to

overcome dry season problems etc)

• Groundwater Aquifer Modelling and Data Collection

needs

• Groundwater enrichment developments and

infrastructure

Urban Water Supply

Water Demand for Pipe Borne water

NWSDB has done several studies in specific areas and

identified that the unaccounted for water is approximately 40 -

45%

It is introducing demand management techniques. In some

areas introducing GIS based models along with metering to

identify loss zones for remedying

Identified that rainwater harvesting should be promoted

No studies are done to determine the actual demand rates or to

identify the optimum allocations for system designs

Pipe borne water at doorstep is available to only 29% of the

population

Training Needs:

• Demand assessment techniques

• Incorporation of land occupancy variations/spatial

variations for the pipe network modeling to arrive at

better estimates

• Spatial Database or GIS based design techniques

for the establishment of such units to carryout

proper assessments in a changing environment

• Assessment of System Losses through

measurements and modelling with sensitivity

analysis to embark on better water management

• Houses of mostly low income – under water

• Roads become impassable – Disrupts economic activities

• Causes traffic congestions – Accidents, Vehicle Maintenance

• Pedestrians in a great difficulty –Splashes from passing by

vehicles, Water Pools to walk in

• Water logging and poor drainage –deteriorate road surface -

huge repair costs

• Mosquito Breeding, overflow of septic tanks, dirty drainages –

causes health hazards

• Urban Area Flooding

Being in the wet zone of Sri Lanka Most Urban Centers

are experiencing rain almost throughout the year, this

is a bigger concern than the water supply. (Urban

Status-Flooding and Drainage –intolerable)

The identified causes for urban flooding -

indiscriminate filling of lowlands, Alteration of

Drainage Paths, increase of impervious areas, and

inadequate drainage designs, and lack of adequate

legislation and commitment

Being an island, in Sri Lanka, urban storm water

management is vital because most of our urban

centres are either located in a river valley, in or close

proximity to an estuary, or by the side of a lake.

In Colombo the water and marshy

wetlands had been nearly 52% but

presently the water bodies and remaining

marshes occupy only approximately 5% of

the land area.

Water Bodies

Marsh

Commercial, Residential

Sanity, Vacant , Utilities

Modification of the drainage

system and Encroachments

The Hydrological assessments are done with models

which have not been verified or having less than

minimum verifications

There are no gauging stations with reliable stage

discharge curves

Except on a project wise, short term basis the RF is

not gauged at a spatial resolution satisfactory for

urban hydrological models

Legislation covers only large scale developments:

cumulative effects are ignored.

Flood Detention and Retention concepts are still

with the engineers awaiting acceptance of the

politicians

Training Needs:

• Urban Hydrology and Drainage issues in low lying and

downstream controlled situations

• Floodplain Management-Flood Retention and

Detention concepts, Design of infiltration facilities etc.

• Methods for Public awareness increase and public

corporation achievement

• Development of Spatially distributed models using GIS

to identify impacts of filling and encroachments

• Network Designs-Establish proper stations RF & SF

gauging

• Compute and Identify Appropriate Design Storms

Quality of Water Bodies

HIGHLY

POLLUTED

CANALS

Kittampahuw

a Ela

2 Water sampling point

Locations of Continuous Monitoring of Water

Quality & Levels

23

1

9

8

7

6

4

2

1

Sea

NORTH LOCK OUTLET TO KELANI

5

Training Needs:

• Water Quality modelling in GIS and identification of Dilution

factors – Lowflow periods, consequences with floods

• Community Awareness of Waste and Wastewater Disposal

• Effects of Disposal on Hydrology and water quality

• Ecological Modelling to Identify alternatives solutions to

improve already polluted water bodies

• Design and maintenance of wetlands for water quality

improvement and flood detention and retention

• Eco Tourism and river environment improvement concepts

• Benefits for low income groups and avenues for income

generation

Governance Issue

The Urban Development Authority under the

Ministry of Urban Public Utilities is vested with the

task of integrated planning and implementation of

economic, social and physical development of

urban development areas in the country, which are

specific areas declared by the Ministry

UDA is vested with very strong powers

Governance Issue

Water Supply

NWSDB is responsible for 95% of the Supply

Two Ministries + Two Authorities + Two Boards and

one Department, are involved in the Urban Water

Supply and Sanitation services – interrelation between

them is complex

The NWSDB has identified funding problems and

therefore promotes private sector investments

It has already been identified to establish an

industry specific water regulator

To ensure better water quality, it has been

identified to promote a “industry citing policy” in

relation to water intakes

There isn’t a clear cut policy on water sharing

between different competing agencies

Governance Issue

Storm Water and Drainage

SLLRDC – Sri Lanka land reclamation and

development corporation is the main agency.

UDA and the Agrarian Services corporation also

play major roles

CEA – the regulating authority

ID – Flood forecasting and fighting

Local Authorities such as Municipal councils,

provincial councils, Urban Councils are also

responsible for the land use and storm water

management

Issues and constraints

Unclear responsibilities among state agencies

for Storm water drainage works. (Different

agencies have different areas of jurisdiction

which are unclear)

Lack of an authorised landuse plan for urban

centers – case by case gives rise to malpractices

Malfunction of the Regulation system for low

land development

-No comprehensive statute for land use

regulation

-No proper evaluation system for land filling

proposals

-No guidelines backed by studies to identify

detention needs

Training Needs

Institutional needs and policy framework for good

governance

Public and State corporation for sustainable

environmental planning and management of storm

water infrastructure

Methods of identifying scientific studies to support

policy formulation

Conclusions

For Sri Lanka it is important that the water supply,

storm water management and water quality

training is strengthened to ensure a sustainable

urban environment.

The urban hydrology along with analysis

techniques through available models should be

taught incorporating the aspect of both spatial and

temporal variability

The training would have to incorporate a component

on group work case studies for practicing water

professionals to identify appropriate solutions.

The training should attempt to incorporate the

techniques of working with the public not only at the

implementation of solutions but also for data

collection, selection of decision making criteria and

making guidelines

Training could include short term training (seminar

type) on new methods, Techniques, Technology –

awareness (senior, middle, technical)

Training could have short term, hands on training

for middle and technical personnel

Collaborative (industry experience) postgraduate

degree programs with state and other funding

assistance (for the young and the enthusiastic)

have to be the foundation

The End

Thank you