Sitting a landfill using a GIS ( ArcGIS 10.3)
- Angela Forero
- Apr 30, 2013
- 4 min read
Before start talking about how to sit a landfill in a specific area, it is important to understand what a Geographical Information System is. A GIS (Geographical Information System) is a system and an useful tool with a large range of applications to visualise, capture, store, analyse, and manage many different kind of spatial or geographical information or data.
Having information in a reliable and organised way helps understand patterns, trends and relationships between variables. For example, GIS can help make better decision when it comes to urban planning as aspects such as biodiversity, water bodies, soil types are considered. If a council is looking into finding a place to sit a landfill several factors need to be taken into consideration:
1.Distance to superficial and ground water
2.Distance to settlements
3. Direction and wind speed
4. Type of road, traffic
5. Distance to natural parks or conservation zones
6. Others.
Making the right decisions on land management is crucial and a great part of local government duties and responsibilities . In this article, we will be focusing on applications of one of the features of ArcGIS 10.3 by reviewing one case study in Victoria.
Landfill Management in Victoria
In Victoria, there are three types of industrial waste. The classification of it, depends on their hazard level. Category A for example is in the highest hazard level, meanwhile 3 is the lowest. As category A is the most dangerous, cannot be accepted at any landfill.
Besides disposing materials in landfills is the least desirable management option, it will still continue to be necessary as a way to manage some wastes that cannot be removed from the waste stream. (EPA VICTORIA, 2015).
It is also important to highlight that landfills should not leave an unacceptable legacy for future generations to address. Land filling is part a waste management strategy, the best practices must be adopted to make sure these places are acceptable to the society.
EPA recommends the following buffers for landfills, in order to protect and mitigate impacts on natural resources and settlements:
Type of landfill number 2: Must be located 100 m from surface waters and 500 m from buildings or structures.
Type of landfill number 3: Must be located 100 m from surface waters and 200 m from buildings or structures
These buffers are set to avoid impacts such as odour, gas from biological decomposition that can also be explosive. Landfill gas potential risk remains for around 30 years post-closure. It is crucial to avoid any settlements in areas that will be affected. Let’s have a look at the study case.
Case Study
The municipality of La Rosa has 13 provinces as shown on map, it has also 5 rivers, 3 small streams and 2 lakes. Some of the rivers supply water to local waterways. Most of the "La Rosa´s" surface belong to residential areas, however, as the population grows, planners have been thinking of opening a landfill that will manage all “La Rosa” waste.
Knowing the buffers set in Victoria, we will be taken into consideration the distance to water surfaces. In the table is shown that there are several streams and rivers, it is not desired to impact negatively people and ecosystems .Using ArcGIS 10.3 software, will be applied a buffer of 100 meters around all the rivers and streams of La Rosa.
The blue intense buffer shows the area that cannot be used to sit a landfill, we also need to include other surface water such as lakes, lagoons that have an important role in the ecosystems such as drainage basin, storage of nutrient content, pH stabilization, and others. Applying this buffer, we obtain:
As it can be seen, the suitable area to sit a landfill has been reduced. It is also important to consider the proximity to buildings and structures. As part of the urban development, there is been built several houses over the past 30 years (black dots). Most of them are spread over the study area, as shown on map.
As it has been said, the buffers are established to protect populations from potential risks such as gas and offensive odours. The buffer applied is 200 m from structures and buildings for a type 3 landfill, besides this, if planners decided that, they would be taking waste from industries and subsequently more hazardous, it would be necessary to use a buffer of 500 m.
As it can be seen, the more dangerous the waste is, the more restricted and smaller the area to sit a landfill becomes.
It is to add that buffers must be measured from the sensitive land use to the edge of the closest cell. All cells need to be taken into consideration.
As a result of mixing all buffers, the next map shows the allowed area for sitting the landfill.
The boundary of the landfill premises is the point of measurement. Buffer measurement also needs to consider other activities capable of causing a nuisance, such as the leachate ponds, to the nearest sensitive land use.
The decomposition and stabilisation of waste in a landfill can take decades, there are many changes and/or impacts that need to be considered such as reduction of the volume of the waste, earthquakes and methane emissions.
In saying that, it is important that the areas the land form is stable, there won’t be human settlements and a suitable future use will be considered. Besides Australia is considered seismically stable, there should be a reasonable degree of assurance in the long term in order to protect the landfill from these natural catastrophes.
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