HYDRODYNAMIC AND ECOSYSTEM MODELLING OF PUTRAJAYA LAKE

Transcription

1 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)

2 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

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

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

5 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

6 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

7 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

8 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

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

10 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

11 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

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

13 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

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

15 Results Wind speed (m/s) Rainfall (mm) Air T (oc) /05 17/05 27/05 06/06 16/06 26/06 06/07 16/07 26/07 05/ /05 17/05 27/05 06/06 16/06 26/06 06/07 16/07 26/07 05/ /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 (%) /05 17/05 27/05 06/06 16/06 26/06 06/07 16/07 26/07 05/08 30 Solar radiation (MJ/m2) /05 17/05 27/05 06/06 16/06 26/06 06/07 16/07 26/07 05/08

16 Diurnal variation a) Seri Bistari Bridge (a) T (oc) m 2.1 m 4.4 m DO (mg/l) m 2.1 m 4.4.m 12:00 00:00 12: :00 00:00 12:00 b) Seri Wawasan Bridge (b) T (oc) m 2.2 m 4.6 m 12:00 00:00 12:00 DO (mg/l) m 2.2 m 4.6 m 12:00 00:00 12: m 5.5 m m 5.5 m 11.0 m c) Dam (c) T (oc) m DO (mg/l) :00 00:00 12: :00 00:00 12:00

17 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<0.09 mg/l, mean Chl-a<7 mg/l Chlorophyta and Bacillariophyta represents 89% of phytoplankton group Most dominant zooplankton group - copepod

18 Results T (deg C) T (deg C) :48 09:36 14:24 19:12 00:00 04:48 09: :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) :48 09:36 14:24 19:12 00:00 04:48 09:36

19 Results Dissolved oxygen Phytoplankton Distribution of water quality during initial condition

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

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

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

23 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

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

25 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 Seri Kembangan, Selangor Hj. Akashah Majizat Lake and Wetland Unit Putrajaya Corporation, 24 Lebuh Perdana, Presint 3, Putrajaya, Malaysia