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CHAPTER 3
METHODOLOGY AND MODEL DESIGN
3.1
MIKE 11 Modeling System
Sources from: Danish Hydraulic Institute (1994).
The core of the flood forecasting system will be the MIKE 11 modeling system.
The MIKE 11 modeling system is a proven engineering software package. The MIKE 11
modeling system is built around a set of integrated modules for hydrology,
hydrodynamics, flood forecasting, advection-dispersion and cohesive sediment transport,
water quality, and non-cohesive sediment transport.
For Klang River Basin, the core system is the hydrology module (NAM) to model
the rainfall-runoff (RR) process, and the hydrodynamic (HD) module to calculate flows
and water levels within rivers and channels. These two modules are integrated so that a
range of problems from simple channel or catchments runoff calculations to complex
river basin problems with multiple rivers and numerous contributing catchments can be
addressed. The hydrodynamic formulation allows branched and looped networks and
quasi two-dimensional flow simulation on floodplains as well as flow over a variety of
structures, broad-crested weirs, culverts, pumps and user-defined structures. In particular
the MIKE 11 Flood Forecasting module is used in automatic real-time continuous
forecasting.
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3.2
Flood Forecasting Module
The MIKE 11 Flood Forecasting (FF) module has been developed to allow
modeling in real-time forecasting situations. It provides a quick and user-friendly data
management system and the transfer of real-time information on rainfall, water level,
discharge, and reservoir operation into forecasts of river flows and water levels.
The MIKE 11 FF module includes the following components:

Calculation of mean area rainfall from point rainfall in a number of subcatchments within the area;

Calculation of discharge from water level data and rating curves or rating tables;

The RR model, using mean area rainfall to calculate sub-catchments inflow to the
river system;

The hydrodynamic module of MIKE 11 for routing the river flow and predicting
water levels and inflow to reservoirs;

An automatic updating procedure which utilizes the measured and/or calculated
discharge or water levels for minimizing differences between observed and
simulated flow/water levels at the time of forecast; and

Specification of quantitative precipitation forecasts and predictions of boundary
inflow in the forecast period.
The MIKE 11 FF systems is fully integrated within the GIS based Flood Watch system.
Flood Watch is dedicated to minimizing the amount of information required to be given
by the operator in the daily forecast routine. All the model calculations required for
issuing a forecast are done automatically in a series of steps. Such a module is ideally
suited for real-time applications, where reliability and fast performance are crucial. Flood
Watch can be used in connection with either a manually based or a fully automatic data
collection and processing system.
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3.3
Flood Mapping
MIKE 11 GIS integrates the MIKE 11 Flood Forecasting modeling technologies
with the Arc View Geographic Information System (GIS). MIKE 11 GIS is ideally suited
as a framework and spatial decision support tool for spatial flood forecasting.
Based on various MIKE 11 inputs and terrain topography MIKE 11 GIS produces
three types of flood maps. These are depth/area inundation, duration and
comparison/impact flood maps.
3.4
Flood Watch
Sources from: Danish Hydraulic Institute (1994), (1995).
Flood Watch is a decision support system for real-time flood forecasting
combining an advanced time series data base with the MIKE 11 hydrodynamic (HD)
modeling and real-time forecasting system, MIKE 11 FF, together with the Geographical
Information System (GIS), Arc View.
Flood Watch comprises a number of separate elements:

The Flood Watch Graphical User Interface (GUI), a customized Arc View project
which provides a live display of station measurements and forecasts;

The MIKE 11 hydrodynamic (HD) modeling system with additional flood
forecasting (FF) module used to produce the forecasts;

The Flood Watch database, for the storage of real-time data; and

A suite of modular tools performing a range of tasks, from data transfer and
processing to forecast plotting and bulletin production.
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The integration of a flood forecasting system in a GIS environment provides a very
powerful tool for real-time flood forecasting and flood warning. Once the database is
established and the graphical display of stations configured, Flood Watch allows for the
fast and easy handling of the procedures involved in the management of a real-time flood
forecasting and warning system.
Input - Telemetry data is imported to Flood Watch from the hydro-meteorological
network through the data conversion module. Import of data can run automatically or
manually.
Quantitative precipitation forecast of weather conditions in the forecasting period can be
imported by means of the data entry module.
Modeling - The model generally runs a "warm-up" simulation period of 6 hours before
the time of forecast and simulates a 3 hours forecast. This has been defined specifically
after evaluating many simulations and based on the fast response of the catchments to
different storms. These parameters can be changed when more experience is gathered
after more on-line rainstorm simulations. However, the selected parameters of Warm-up
simulation = 6 hours and Forecast period = 3 hours may be in the average range. Once a
request for a forecast is made, the system will automatically extract the required data
from the Flood Watch database to MIKE 11, execute a model simulation and transfer the
MIKE 11 simulated forecasts to the Flood Watch database for display and further
dissemination.
Output - The graphical display in Arc View is automatically updated with the most
recent flood information. In addition forecasts can be produced as graphs of measured
and forecast water levels and discharges, as printed bulletins or saved in HTML format
for display on an Intranet or the Internet.
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3.5
Modeling Setup
To setup the modeling system for this study, the parameters such as rivers
network, cross-section, boundary data, time series, HD and RR parameters are created
according to the existing situation and for the future-planning situation of the Klang
River Basin system. Each of the system is created separately for the purpose of
comparison of each system.
3.5.1 Network Setup
This setup is to join up the entire river network in Klang River Basin. All the river
alignments are joining up according to the chainage from the plans. In this study, the
SMART Tunnel alignment is setup according to the plan. The example of this setup is
show in Figure 3.5.1.
Figure 3.5.1: Network Setup
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3.5.2 Cross-Section
This setup is to input the cross-section of the river system according to the plans as given
by surveyor. The physical of Cross-section River changed in different chainage. Besides
that the radius of the river is also considered in this setup. This process is the most
difficult part of the study and is time consuming. Figure 3.5.2 show the cross-section
setting.
Figure 3.5.2: Cross-section Setup
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3.5.3 Boundary Data
This setup is the most important part of the modeling system. It contains with
Hydrodynamic data that need the time series data of all the river discharge and water
level values. In this study, the river system with and without SMART use the same time
series so can see the result of the maximum discharge and water level. The setup is
shown in Figure 3.5.3(a) to (c)
Figure 3.5.3(a): Boundary Data Setup
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Figure 3.5.3(b): Discharge Time Series
Figure 3.5.3(c): Water Level Time Series
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3.5.4 Hydrodynamic
This setup is to input all the initial bed level and discharge data for every chainage of all
the rivers. It also needs the wind factor, bed resistant and many parameters as shown in
Figure 3.5.4.
Figure 3.5.4: Hydrodynamic Parameters
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3.5.5 Simulation
Simulation is the final stage of the modeling setup where it simulates all the parameter
data that was created. It needs to call in all the parameter files to run the simulation. The
simulation will provide the result of discharge and water level for the whole system of
Klang River Basin. The example of this setup is shown in Figure 3.5.5.
Figure 3.5.5: Simulation Setup