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Researchers :
Prof. Dr. Nor Azazi Zakaria <redac01@eng.usm.my>
Prof. Dr. Aminuddin Ab. Ghani <redac02@eng.usm.my>
Zorkeflee Abu Hasan <redac04@eng.usm.my>
Leow Cheng Siang <redac21@eng.usm.my>
Chang Chun Kiat <redac10@eng.usm.my>
Mohd Fazly Yusof <redac07@eng.usm.my>
Muhamad Nurfasya Alias <redacfasya@eng.usm.my>
Muhammad Zaki Mohd Kasim <redaczaki@eng.usm.my>
Study Area and Problem Statement :
Paddy fields are found
majority in the Asian regions where it contributes staple food i.e. rice
which are consume by almost half of the world's population in this
region. Paddy fields have multifunctionalities or multiple roles (e.g.
food production and security, flood control, water purification, social
economic improvement, preservation of soil erosion, cultivation of
ground water, habitats of aquatic animals, reduction of nitrogen content
in irrigation water, climatic mitigation agro and eco-tourism and
amenities, cultural and education, etc..) which are important to the
stakeholders.
This study is part of
Malaysia's continuous support to the International Network of Water and
Ecosystem of Paddy Fields (INWEPF) in promoting the benefits of paddy
cultivation beyond rice production. The Malaysian INWEPF Chapter,
through Agriculture Drainage and Irrigation Division of the Ministry of
Agriculture and Agro-based Industry Malaysia, has initiated this study
to provide scientific evidence of such multi-functionalities of paddy
fields in Malaysia.
REDAC (through USAINS Holdings Sdn Bhd) was appointed by
Ministry of Agriculture and Agro-based Industry Malaysia to conduct this
study, concentrating on the capacity of paddy fields in providing flood,
sedimentation and erosion control. The 8-month study will be conducted
in selected paddy plots in Pendang, Kedah, which is under the Muda
Irrigation Scheme, operated and managed by Muda Agricultural Development
Authority (MADA).
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Figure 1: Location
of Study Area |
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Figure 2: Study
Plot and River |
Scope of Works :
The scope of this study
includes:
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To study the
effectiveness for the flood, soil erosion and sediment control of
paddy fields under the context of sustainable paddy cultivation.
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To produce
guideline or standard format on the planning aspect to execute this
study or task.
Multi Functionality of
Paddy Fields :
Multifunctionality of
paddy field has been widely studied in developed rice-growing countries
such as Japan, Korea and Taiwan. However, very few if any, of such study
have been conducted in Malaysia, or the South East Asia region. Table 1
summarised some of the multifunctionalities of paddy field documented by
several literatures. Among some widely acknowledged functions of paddy
fields include flood control, erosion control and water purification.
Monetary evaluation suggested that these multifunctionalities of paddy
field could provide millions in benefit of the people and government.
These saving come from mitigating possible flood, land slide hazard, and
mitigating draughts, as showed in Table 2.
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Function: |
Masumoto (2003) |
Matsuno et al. (2006) |
Huang et al. (2006) |
Kim et al. (2006) |
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Water Cycle Control |
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Flood control
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Groundwater recharge
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Soil erosion prevention
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Flood alleviation
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Groundwater recharge
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Environmental Load Control |
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Nature Formation |
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Social and Cultural Formation |
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Health and recreation
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Participatory learning
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Negative Impact |
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Water contamination
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Methane emission
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Pesticide contamination
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Methane gas emission
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Disturbance and extinction of ecosystem
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Excessive use of fertilizers and pesticides
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Over withdrawal of surface and groundwater.
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Table 1: Multifunctionality of paddy fields
Table 2: Monetary evaluation of Multifunctionality of
Paddy Fields
(Kim et al., 2006)
Study Methodology :
The study will be conducted in two parts to examine the
flood and sediment control capacities of paddy fields. In each part, the
functions will be examined in two scales, namely micro (local) and macro
(regional) scales. Finally, the flood and sediment control capacity will
be determined, and the findings will be compiled and documented as a
guideline for paddy fields flood and sediment control assessment and
management practices. Figure 3 illustrates the proposed work flow for
the study.
Figure 3: The proposed study methodology
In order to determine flood control capacity of paddy field, two
assessments will be carried out. First, a plot water balance model will
be established at 3 selected plots within study area to examine the
capacity of paddy field in reducing rainfall runoff. Field works will be
carried out to survey the plots, determine soil infiltration rate, and
hydraulic parameters. It is expected that flood control capacity will
vary due to seasonal changes (soil condition) and farmer's practices.
This study will also look into these factors. Second assessment will
determine how paddy plots collectively perform as floodplains in order
to mitigate regional flood. A hydraulic model will be used to examine
the effect of having paddy field floodplains in Pendang area.
As for sediment control, there will also be two
assessments to be carried out. Firstly, the plot level sediment control
of paddy field will be determined. As water enters paddy plots through
irrigation canal in normal operation condition, it will flow through the
plot and exits at the outlet of the plot into agricultural drainage.
There will be expected change of sediment content due to the change of
flow regime during this period. Several factors which will affect this
change include flow, farmer's practice, and crop growth stages. The
sediment control relationship to these factors will be determined.
Second assessment involves determination of sedimentation capacity of
paddy plots in regional scale. As river flood occurs, paddy fields as
floodplains will attenuate flood flow, thus encouraging settlement of
larger particles. This phenomenon will be simulated using sediment
transport computer model.
Study Deliverables
:
The final output of the
study will include the assessment of flood and sediment control in the
Pendang paddy fields as a representation of Malaysia paddy cultivation
practice in general. The study is also expected to identify factors
influencing flood and sediment control capacity of paddy fields
including plot physical condition, crop growing stages, and farmer's
practices.
Finally, the
methodology applied in this study will be properly compiled and improved
at the end of the study to provide guidelines for any future paddy field
multifunctionality evaluation, particularly for flood and sediment
controls. Suggestions to optimise flood and sediment control capacities
will also be documented to maximize values of paddy cultivation.
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