GIS as Decision Support Tool for Landfills Siting

GIS as Decision Support Tool for Landfills Siting

Gaim James Lunkapis
School of Social Sciences
Universiti Malaysia Sabah
Locked Bed 2073
88999 Kota Kinabalu, Sabah
Malaysia
Tel: +60-88-320000 ext 1832
Fex: +60-88-320242
Email: gaim@ums.edu.my
Web: www.ums.edu.my

Introduction
The purpose of this research is to use Geographic Information System (GIS) as a tool to aid the decision-making process and to test its effectiveness using some established government guidelines in the state of Sabah.

Landfill Siting Guidelines
During the last few years, Malaysia has come up with more structured waste management systems. In 1998, the Ministry of Housing and Local Government announced a policy known 2 as “A Beautiful and Clean Malaysia (ABC)”, which contained a strategy, by the government to immediately improve the level of waste management in all levels of administration especially in the Municipal Councils and Local Authorities.

Along this line, in 1995, the Department of Environment had published a guideline for selecting landfills sites known as Constraint Mapping Techniques (CMT). According to the guidelines, CMT shall be used to designate areas, which have unsuitable physical and other environmental characteristics. With unsuitable areas excluded, potential sites can simply be selected based on the remaining areas. According to the guidelines, sites can be selected based on performance basis, on ability and on economic grounds. Potential sites are then subject to rapid preliminary screening to narrow down numbers to more desirable sites which would then be subjected to detail evaluation studies.

The second step suggested by the guideline was to further screen the potential sites. A minimum of 3 sites should be selected in order to allow a reasonable comparison and allow the retention of alternate sites if the preferred site proved unworkable. Screening is conducted based on conceptual design and costing for the sites in question in addition to a selected specific set of critical environmental criteria. Due consideration must be given to key environmental issues associated with a specific project either by quantitative or qualitative ranking systems so that the best site can be designated for landfill site. The landfills site selection guidelines produced by the government in 1995 stressed that although the above process can identify a preferred site, its selections cannot be confirmed prior to completion of the feasibility study and the Environmental Impact Assessment (EIA) studies. This particular research will only cover the first step of the said guideline.

General Site Selection Criteria
Criteria used to determine the most suitable site for landfills have been identified based on the guideline produced by the Ministry of Environment, Malaysia in 1995 and also in collaboration with the Sandakan Spatial Planning Working Group. The criteria were both constraints and factors for an ideal siting of landfills. The constraints were related to roads, open water, protected areas, urban, rural residential areas, soil permeability and soil type, land use/land cover and distance to transportation routes. The above criteria were than refined according to the existing and established guidelines in Sabah and also in agreement with the Sandakan Spatial Planning Working Group, which are briefly explained in the following paragraphs.

1) Proximity to surface water
A landfill must not be located near any surface streams, lakes, rivers or wetlands. For this reason, a 100-meter buffer would be placed using the function in GIS software, which will be used to generate the buffer around all surface waters such as streams, lakes and wetlands. The 100-meter buffer is in line with riparian reserve guidelines produced by the Drainage and Irrigation Department, Sabah.

2) Distance from transportation routes
Aesthetic considerations would be of good practice for good planning and based on this principle, landfills shall not be located within 100 meters of any major highways, city streets or other transportation routes. The 100 meters was chosen based on the current practice provided under supplementary guidelines for development of residential, industrial and commercial sites under the Department of Town and Regional Planning, Sabah.

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