putrajaya lake

NATIONAL SEMINAR ON
ECOSYSTEM MANAGEMENT FOR LAKES AND WETLANDS PUTRAJAYA 2013
HYDRODYNAMIC AND ECOSYSTEM MODELLING
OF PUTRAJAYA LAKE
Dr. Zati Sharip
Head Lake Research Unit
Research Centre for Water Quality and Environment
National Hydraulic Research Institute of Malaysia (NAHRIM)

Zati Sharip 1 , Normaliza Noordin 2 , Jarina M.Saman 2 ,
Saim Suratman 1 , Ahmad Jamalluddin Shaaban 1 & Akashah Hj Majizat 2
1
National Hydraulic Research Institute of Malaysia (NAHRIM)
2
Lake and Wetland Unit, Putrajaya Corporation

Outlines
• Introduction
• Description of the Putrajaya Lake
• Objectives
• Materials and method
• Data Collection
• Model set up and simulation
• Results
• Summary

Malaysia’s administrative Centre
Photo: Perbadanan Putrajaya
PUTRAJAYA LAKE
A scenic and self-sustaining ecosystem for
recreation, sports and tourism

PUTRAJAYA LAKE AND WETLANDS
• Part of Langat River
Basin
Langat River
• Catchment area 51.0
km 2
• 56% discharges
into wetlands
• 44% flows directly
into lake

THE PUTRAJAYA LAKE
• Surface area of
400 hectares
• An average depth
of 6.6 m
• Mean hydraulic
retention time of
132 days
Natural filtration system
Source: Perbadanan Putrajaya

Challenges
• Increasing development & land use
changes
• Vulnerable to pollution
• The need to retain lake water quality at
high standard
‣ Integrated catchment management
‣ Continuous environmental monitoring
‣ Development of Ecosystem model

Objectives
• To understand the ecohydrological
dynamic for
sustainable management of
these urban water-bodies
• To monitor the aquatic
environment response to the
increasing development and
land-use changes, coupled
with climate variations

Methodology
Field Data:
Meteorological, flow, Bathymetry
Hydrodynamic model
Ecosystem model
Field data:
Water quality, biological
Calibration and verification
Analysis

Data Collection
Weather monitoring station
Rainfall station
Flow Measurement
Water level Measurement
Presint 13
Presint 11
Presint 1
Presint 7
Presint 2
• Weather and rainfall
monitoring
Dam
• Water level and flow
measurement

Data Collection
Biological Measurement
WQ Measurement
Diurnal WQ Measurement
• Water quality measurement
(monthly, bi-weekly, diurnal)
Seri Wawasan
Brudge
Seri
Bistari
Bridge
Photo: Perbadanan Putrajaya
• Biological surveys
Dam
Photo: Perbadanan Putrajaya

Model set-up and assumptions
• Lake shoreline and depth
data - bathymetry survey
• Complex morphology
• Depth varies from ~ 3m
(upstream) to ~14 m
(downstream)
0 305 610 m

Model set-up and assumptions
• Grid size 100m x 100m
• Inflow estimation based on
designed flow ratio
• Exclusion of groundwater
exchange
• Simulation period – dry
season

Model Coupling
Hydrodynamic Model
Scalar transport
Thermodynamics
Boundary Conditions
Initial Conditions
Ecosystem Model
Water Quality
Biochemical
parameters

Results
Wind speed
(m/s)
Rainfall (mm)
Air T (oC)
6
4
2
0
07/05 17/05 27/05 06/06 16/06 26/06 06/07 16/07 26/07 05/08
40
20
0
07/05 17/05 27/05 06/06 16/06 26/06 06/07 16/07 26/07 05/08
40
30
20
07/05 17/05 27/05 06/06 16/06 26/06 06/07 16/07 26/07 05/08
• Low wind
speed
• Low lake
inflow
• High solar
radiation
Humidity (%)
100
50
0
07/05 17/05 27/05 06/06 16/06 26/06 06/07 16/07 26/07 05/08
30
Solar radiation
(MJ/m2)
20
10
0
07/05 17/05 27/05 06/06 16/06 26/06 06/07 16/07 26/07 05/08

Diurnal variation
a) Seri Bistari Bridge
(a)
T (oC)
32
31
30
0.3 m
2.1 m
4.4 m
DO (mg/L)
8
6
4
0.3 m 2.1 m 4.4.m
12:00 00:00 12:00
2
12:00 00:00 12:00
b) Seri Wawasan Bridge
(b)
T (oC)
32
31
30
0.3 m
2.2 m
4.6 m
12:00 00:00 12:00
DO (mg/L)
8
6
4
2
0.3 m 2.2 m 4.6 m
12:00 00:00 12:00
32
0.3 m
5.5 m
8
0.3 m 5.5 m 11.0 m
c) Dam
(c)
T (oC)
31
30
11.0 m
DO (mg/L)
6
4
12:00 00:00 12:00
2
12:00 00:00 12:00

Results
• Water quality levels comply with the Class IIB
requirement
• Some parameters exceed the Putrajaya Lake and
Wetlands Water Quality Standards
• chlorophyll, total coliform and ammoniacal-N
• TSI – Mesotrophic; TP

Results
T (deg C)
T (deg C)
32
31
30
04:48 09:36 14:24 19:12 00:00 04:48 09:36
32
31
30
04:48 09:36 14:24 19:12 00:00 04:48 09:36
Reasonably matched
between simulated and
observed variables
•Temperature
•DO
T (deg C)
32
31
30
04:48 09:36 14:24 19:12 00:00 04:48 09:36

Results
Dissolved oxygen
Phytoplankton
Distribution of water quality during initial condition

Results
High-wind event
• South-west
Simulated velocity under different wind condition

Results
• Convective motion
• Differential
cooling
Low-wind event
Simulated velocity under different wind condition

Results
High-wind event
Low-wind event
Simulated DO and phytoplankton under different wind condition

Summary
• Coupled hydrodynamic and ecosystem modeling
• Guide intensive and coordinated data collection
program
• Provide understanding on the eco-hydrological
dynamic in lakes
• Useful to monitor the aquatic environment
response to the increasing development and landuse
changes, coupled with climate variations

Way forward
‣ Long-term simulation & validation
‣ Continuous & intensive data
‣ Model simulation to predict pollution scenarios
and recommend mitigation program

Thank you
For further details:
Dr. Zati Sharip
Lake Research Unit
Research Centre for Water Quality and Env.
National Hydraulic Research Institute of Malaysia
Lot 5377, Jalan Putra Permai
43300 Seri Kembangan, Selangor
Email: zati@nahrim.gov.my
Hj. Akashah Majizat
Lake and Wetland Unit
Putrajaya Corporation,
24 Lebuh Perdana, Presint 3,
62675 Putrajaya, Malaysia
Email: akashah@ppj.gov.my