Land use temporal changes: a comparison using GIS analysis and statistical analysis...

Land use temporal changes: a comparison using GIS analysis and statistical analysis on the impact of water quality at Langat River Basin, Malaysia

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Hafizan Juahir
Chemistry Department, Faculty of Science, University Malaya

Sharifuddin M. Zain, M. Nazari Jaafar
Geography Department, Faculty of Art and Social Science, University Malaya

Zainal A. Majeed
School of Civil Engineering and Geosciences, University of Newcastle upon Tyne

M. Ekhwan Toriman
Centre of Environment, University Kebangsaan Malaysia

Abstract Extended Abstract
Land use change has been a critical issue for planning and management of resources and for modernisation agenda in most developing countries. Significant measure has been implemented to identify the feasible land use activities that could lead to disaster to human and issues to the development of infrastructure. According to United Nations assessment (1996), during the period from 1990 to 1995 the average annual urbanization rate in developing countries, were over 3.4% compared to only 0.7% in developed countries. Agricultural practice has been a major factor that can result in adverse impacts on the health of aquatic systems through contaminant and nutrient. Due to rapid urbanization, the water sector can cause two types of impacts: high demand for freshwater and serious pollution of the available water resources. River water pollution is caused by several effluents from local factories and other land use activities and their effects are of great concern to health. Disposal of waste water generated from municipal and industrial sources with little to no treatment prior to discharge is common practice in many developing countries such as Malaysia. As a result of population growth and increasing industrialization, serious problem of the water quality are commonplace. To deliver some of the issues and evaluate the possible outcomes of land changes management and water quality impact a study was taken using environmental and land use data surrounding the Langat River Basin in Malaysia.

Geography Information System (GIS) application was utilized to measure and evaluate the temporal changes in land use from year 1984 to 1990, 1990 to 1995 and 1995 to 1997 in the Langat River Basin. Four land-use maps of 1984, 1990, 1995 and 1997 were used in the study. A GIS analysis was carried out to quantify the land-use structure. According to ESRI (1995), GIS is defined as “computer system capable of holding and using data describing places on the earth’s surface. A GIS contains two types of information: (1) spatial information describing location and shape and (2) descriptive information relating features. The analysis was carried out using ESRI’s Spatial Analysis extension in ArcGis 8.2.

At the same time statistical analysis basically using Shannon Diversity Index (SDI) was employed to evaluate the impact of water quality of the river. Discharges (Q) and several water quality parameters were selected to measure the changes in water quality. The six selected parameters water quality were dissolved oxygen (DO), biological oxygen demand (BOD), chemical oxygen demand (COD), suspended sediment (SS), ammonia nitrogen (AN) and pH. The historical data was observed from seven sampling station monitoring by ASMA along the river basin. GLM3 was applied to test the significant of the relationship among the water quality itself and how strong the relationship with the land use within the buffer area. The analysis was accomplished using statistical software SPSS 10.0.

The objective of the study were: (1) to identify the land-use changes within the 1984, 1990, 1995 and 1997 in a Langat River Basin (2) to integrate the Langat River Basin ecology and GIS monitoring for land-use management (3) to analyze the relationships between land-use and water quality parameter. The research highlights some the issues in carrying out management and monitoring of land use activities and river water quality precaution.

The study area was divided into four sub-basins: downstream (DS), middle stream lower (MSL), middle stream upper (MSU) and upstream (US). The land-use analysis was carried out surrounding the main river areas. This study applied GIS to determine what type of land-use within the surrounding main rivers and calculate the indices of the land-use structure. The indices were then used to analyze the land-use changes in the study area. Two indices were used to characterize the land-use composition, that is Shannon Diversity Index (SDI) and patch richness (PR). To examine the variation of land use changes in the study area the t test is applied. This is based on the SDI and the equation as follows:


where LUi is the Shannon diversity index of land-use i or stage i, mi is the number of patch types, ni is the number of patches and Pj refers to the percentage of either the number of patch type j to the total number of patches. s2LU, is the variance and its equation and degree of freedom are as follows:


The result of the GIS analysis showed that land use change around the basin from 1984 to 1990 is not significant. Similar result was obtained for the period from 1995 to 1997. However, major land use changes occurred from 1990 to 1995. Components of land use are mostly composed of forest, grassland, horticulture, improved permanent, permanent crops, urban settlement, water bodies and others. To evaluate this significant effect on land-use changes between the interval years, a statistical test was carried out to test the extent of land-use changes. A t-test of SDI at 5% significant level was obtained. The result indicated that land use changes for interval years from 1984 to 1990 and from 1995 to 1997 are insignificant, while for 1990 to 1995, the result indicated a significant change. Eventually the rapid changes in land use can be pointed out by the resultant value of Shannon Diversity Index (SDI) which is significantly higher for 1995 (2.5923) compared to 1990 (1.0198).

In term of discharge, the result supported the decision to reject the null hypothesis concluding that there are significant differences between the discharges volume for 1984, 1990, 1995 and 1997 seasons at station 2917401 in the upper stream where land use has shown differences. As for the lower stream at station 2917401 the result supported the decision to accept the null hypothesis to conclude that there are no significant differences between the discharges volume for 1984, 1990, 1995 and 1997.

In summary, this paper has successfully addressed some of issues surrounding land use changes and the impact on water quality in the Langat River Basin. The full paper will describe more results and details in each part of analysis and draw upon detailed outcomes of the further implemented evaluation. The research would establish further findings and links between the two types of analysis adapted in the full version of the paper.