Nor Aizam Adnan

Event-based rainfall-runoff modelling of the Kelantan River Basin

Flood is one of the most common natural disasters in Malaysia. According to hydrologists there are many causes that contribute to flood events. The two most dominant factors are the meteorology factor (i.e climate change) and change in land use. These two factors contributed to floods in recent decade especially in the monsoonal catchment such as Malaysia. This paper intends to quantify the influence of rainfall during extreme rainfall events on the hydrological model in the Kelantan River catchment. Therefore, two dynamic inputs were used in the study: rainfall and river discharge. The extreme flood events in 2008 and 2004 were compared based on rainfall data for both years. The events were modeled via a semi-distributed HEC-HMS hydrological model. Land use change was not incorporated in the study because the study only tries to quantify rainfall changes during these two events to simulate the discharge and runoff value. Therefore, the land use data representing the year 2004 were used as inputs in the 2008 runoff model. The study managed to demonstrate that rainfall change has a significant impact to determine the peak discharge and runoff depth for the study area.

Temporal geospatial analysis of secondary school students' examination performance

Malaysias Ministry of Education has improved the organization of the data to have the geographical information system (GIS) school database. However, no further analysis is done using geospatial analysis tool. Mapping has emerged as a communication tool and becomes effective way to publish the digital and statistical data such as school performance results. The objective of this study is to analyse secondary school student performance of science and mathematics scores of the Sijil Pelajaran Malaysia Examination result in the year 2010 to 2014 for the Kelantans state schools with the aid of GIS software and geospatial analysis. The school performance according to school grade point average (GPA) from Grade A to Grade G were interpolated and mapped and query analysis using geospatial tools able to be done. This study will be beneficial to the education sector to analyse student performance not only in Kelantan but to the whole Malaysia and this will be a good method to publish in map towards better planning and decision making to prepare young Malaysians for the challenges of education system and performance.

Remote sensing of river bathymetry for use in hydraulic model prediction of flood inundation

Many studies have been carried out for bathymetry mapping based on remotely sensed imagery coupled with ancillary datasets. Most of the techniques that have been developed are mainly used for shallow and clear water rivers, while deep, turbulent and highly suspended sediment rivers have received little attention in terms of developing new techniques. The aims of this study were (i) to predict a bathymetry map by remote sensing and (ii) to map flood extent for the River Kelantan, Malaysia using a hydraulic model based on the bathymetry map. Firstly, a regression model was fitted to the relation between river depth and a SPOT satellite sensor image. The results showed a large correlation between river depth and the green band. Secondly, an image processing technique (i.e. density slicing) was applied to the SPOT image to classify river water depth and thus produce a map of bathymetry. A hydraulic model (HECRAS) was then used to predict flood inundation extent and the result compared to flood extent predicted from a RADARSAT image. The accuracy assessment was applied to identify spatial variation in the error between three areas (i.e. upstream, midstream and downstream).

Rainfall Trend Analysis and Geospatial Mapping of the Kelantan River Basin

Trend analysis was widely used as a tool to detect changes in climatic and hydrologic time series data such as rainfall. Fourteen rainfall stations in the Kelantan River Basin were used to detect trends for each of the sub-basin areas. Two objectives of the study are (i) to quantify the changing trends of rainfall of Kelantan River using statistical tests (i.e., Mann-Kendall test and Sen’s slope test) based on monthly, seasonal, and annual time series, and secondly, (ii) to map rainfall trend according to Mann-Kendall test result. Analysis for these two tests revealed that several stations indicated significant increasing and decreasing trends for monthly, seasonal, and annual rainfall time series. The study found that rainfall varies in different months, seasons, and annually as evidenced by the graph and trend maps. Therefore, this information will benefit especially for flood preparation and responses in Kelantan River Basin which annually experiences monsoon flooding.

Climate variability and anthropogenic impacts on a semi-distributed monsoon catchment runoff simulations

Recent studies has showed that the modification on land use have an impact to hydrology particularly flood and global climate variability. Therefore, the major factor decided to the effect of hydrological responses in contributing flood disaster in this research, is land use changes as well as climate variability. This study tries to provide a framework mainly to apply a semi-distributed hydrological model in a monsoon catchment and to quantify the relative contributions of physio-environment (i.e. land use change and climate change) effects to hydrological response and flooding in the River Kelantan catchment. The HEC-HMS hydrological model was utilized to show that land use change, predominantly deforestation for agricultural purposes, has potentially caused some increases in hydrological response over time (i.e. 16 years) in the upstream area. However, the predicted effect of precipitation change was about three-to-four times greater than that of land use change in the upstream area. In the downstream area land use change was predicted by the model to have led to a very small decrease in hydrological response between 1988 and 2004 compared to the precipitation change. It is plausible to suggest that during the monsoon season, with heavy precipitation and the large area involved, the effect of land use change on the hydrological response may reduce and allow precipitation to become the dominant factor in causing changes in peak discharge and runoff volume.

Delineation of wetland areas from high resolution WorldView-2 data by object-based method

Various classification methods are available that can be used to delineate land cover types. Object-based is one of such methods for delineating the land cover from satellite imageries. This paper focuses on the digital image processing aspects of discriminating wetland areas via object-based method using high resolution satellite multispectral WorldView-2 image data taken over part of Penang Island region. This research is an attempt to improve the wetland area delineation in conjunction with a range of classification techniques which can be applied to satellite data with high spatial and spectral resolution such as World View 2. The intent is to determine a suitable approach to delineate and map these wetland areas more appropriately. There are common parameters to take into account that are pivotal in object-based method which are the spatial resolution and the range of spectral channels of the imaging sensor system. The preliminary results of the study showed object-based analysis is capable of delineating wetland region of interest with an accuracy that is acceptable to the required tolerance for land cover classification.

Disentangling the effects of long-term changes in precipitation and land use on hydrological response in a monsoonal catchment

This research aimed to quantify the effects of precipitation and land use changes on the hydrological response (peak discharge and runoff volume) in the River Kelantan catchment, Malaysia. Two periods were studied, involving the years 1988 (lower hydrological response) and 2004 (greater hydrological response). Rainfall and land use observed for the year 1988 was used in the calibrated and validated model for 1988, but also used in the calibrated 2004 runoff model to simulate the impact of changes in these two factors on runoff generation. For the upstream gauge, differences in peak discharge and runoff volume were affected more by land use change compared to climate-related changes (i.e. precipitation). However, changes in hydrologic response in the downstream catchment were much more associated with precipitation changes. From these findings, we suggest that both land use and climate changes (i.e. precipitation) contributed to changes in hydrologic response in the Kelantan monsoonal catchment, but that for the downstream catchment, which is more prone to flooding, with associated potential socio-economic impacts, precipitation change is the major driver. The results have clear implications for planning and management decision-making.

Tree species classification using worldview-3 data

Tree species identification is a crucial matter in forest managing and supervision. In recent years, tree species identification has been studying a lot using high-resolution satellite imagery data of 0.5m spatial resolution Worldview-3. This has because of some of the tree species have very high market value type of wood. Besides that, Tropical forest stored a large stock of carbon that contributes to the huge amount of above and below ground biomass. Hence, tree species identification is important in order to manage and control such activities like critical timber logged, forest cut for agricultural and development purposes that would affect the carbon cycle and lead to global warming affect. Tree classification using conventional method is required more time and limited accessibility for site survey, so the remote sensing technology was applied to identify tree species. In this study, tree species classification was done to identify dominant tree species had in Ayer Hitam Forest Reserve Puchong to estimate biomass values. Support Vector Machine (SVM) supervised classification method was applied in this process. This study can give some ideas to researchers in the future on what type of improvements can be made for next research and is hoped to assist the forest managers to control and manage forest ecosystems in order to reduce climate change.

Land Use Change Effects on Extreme Flood in the Kelantan Basin Using Hydrological Model

Land use and land cover (LULC) change results in increased of flood frequency and severity. The increase of annual runoff which is caused by urban development, heavy deforestation, or other anthropogenic activities occurs within the catchment areas. Therefore, accurate and continuous LULC change information is vital in quantifying flood hydrograph for any given time. Many studies showed the effect of land use change on flood based on hydrological response (i.e., peak discharge and runoff volume). In this study, a distributed hydrological modeling and GIS approach were applied for the assessment of land use impact in the Kelantan Basin. The assessment focuses on the runoff contributions from different land use classes and the potential impact of land use changes on runoff generation. The results showed that the direct runoff from developmental area, agricultural area, and grassland region is dominant for a flood event compared with runoff from other land-covered areas in the study area. The urban areas or lower planting density areas tend to increase for runoff and for the monsoon season floods, whereas the inter-flow from forested and secondary jungle areas contributes to the normal flow.

Utilizing What-if? 2.0 GIS planning support system for future potential land use development area simulations

This study intend to utilize GIS planning support system software (i.e. What-if 2.0 software) with remote sensing and Geographic Information System techniques to quantify current land use as well as future suitable land for development. There are two objectives of this study, i) to identify the existing (i.e. years 2004 and 2010) land use area using digital image processing of satellite imageries of SPOT-5 image, 2) to propose potential future land development area based on appropriate suitability factors with the aid of the GIS planning support system software (i.e. ArcGIS 9.3 and What-if? 2.0). As a result, the approach proposed in this study is appropriate to provide alternative method for urbanization land development with the purpose of development suitability area. With the proposed spatially planning support system tool as presented in this study, hopefully it will aid better land use planning decision processes and making in the future.