Protecting the Land: Strategies to Prevent Devastating Landslides

Various landslide prevention techniques had to be considered in order to find the best fitting solution. The solutions investigated are simple yet effective in strengthening the slopes in the absence of detailed soil or bedrock analysis or in low-risk situations. In how to prevent landslides essay this topic will be considered.

The first solution discovered was a drainage system. The use of drains is becoming increasingly widespread in slope stabilisation. This technology is less costly than other types of control works and is suitable for a large number of situations, even when the landslide is very deep and structural measures are inadequate. But suits Timor Leste due to the 2000 km of rough mountains terrain, with almost half of its surface being sloped between 40 and 90 degrees. When slope analysis is carried out, it provides results of detailed, accurate calculation of pore pressures. This information can be used to determine the factor of safety of the slope as well as precisely determine where the drains must be. According to the Faculty of Civil Engineering, Department of Geotechnics, Slovak University of Technology, this technique, on average, discharges 45% of the moisture in a slope.

The initial large dis-charge is mostly because of static groundwater reserves. Water from rainfalls and inflowing groundwater is not sufficient source to recharge the slope to a level of potential landslide due to the discharge of water being of greater volume. This strategy has proven to work, namely in Sele Valley, Italy, where a landslide was stabilised by drainage even though groundwater regime was monitored for a long period of time. The slip surface was found to be at immediate risk; however, the relatively cheap and quick implementation of the drainage successfully reduced the moisture levels by 30-40%. This raised the slopes factor of safety to 1.2–1.3, which is considered large. Slope drainage systems have proven to be an effective and reliable strategy to reduce landslide risk, but it does have downsides which would be enlarged if applied to a developing country. Inspections of already built systems reveals the development of corrosion of casting with filter, mechanical clogging with fine sludge, chemical and biochemical clogging with iron oxides, CaCO3 precipitation or overgrowth of borehole head with algae and moss or even with plant roots. These issues would require an EWB to fly in multiple industry professionals to correct the issue, due to the system being unsustainable by the population of Timor-Leste.

Another solution found to be effective against landslide prevention is the plantation of deep-rooted crops. This technique’s aim to prevent landslides as much as possible. In addition, deep-rooted crops on the hillsides or mountainsides can develop to hold soil together if the deforestation happens. When taking the context of Suco Holarua and Timor-Leste into account, deep-rooted crops are the most effective type of vegetation because of the food insecurity in Timor-Leste. Some common deep-rooted crops include pumpkin, tomato and watermelon. In addition, the soil pH in Suco Holarua is relatively in good condition, elephant grass and vetiver grass are chosen the best for deep-rooted vegetation.

There are many benefits of deep-rooted vegetation. Firstly, deep-rooted crops can help to stabilize the soil layers and improve water drainage, especially during rainy seasons. This is due to the plant’s foliage being able to prevent and hold back the compaction of the soil, which protects the soil from heavy rain and livestock. The deep roots create many small passages and spaces to allow for water to move easily, allowing moisture percolation, as well as essential microorganisms to increase the health of the soil. As the soil layers stable and the water drainage improved, the landslide can be easily prevented. The second advantage is that it can help to prevent erosion. As the consequence of the exposed ground which makes higher risk of erosion by wind and water runoff, deep-rooted crops can help to stabilize the ground and soil, which helps to prevent runoff and improve the structures. Improving the ground structures means that the structures is stronger and more stable, which can prevent landslide. The third advantage is that improving the moisture in soil. Using deep-rooted crops is an efficient and effective solution to conserve and develop the moisture content of the soil. This technique helps cover the soil and protect the vaporization by the hot weather caused by the sun or from the windy weather. In addition, deep-rooted crops can bring up moisture from lower down in the soil from the ground. Thanks to improving the moisture, the risk of landslide may decrease. The last benefit is that improving the nutrients. Making use of deep-rooted crops can provide and develop valuable nutrients to the soil, which can provide essential elements for the plants to grow. Moreover, the deep-rooted crops can extract nitrogen, which is one of the most valuable and important elements. Not only there is an increasing in levels of nitrogen in the soil ground from the original plants, but also when the plants die, the soil still keeps the nitrogen in the soil and make this element available to new plants on the ground.

The third and final option for a long-term landslide prevention strategy are eco briquettes. Raw coal is still burnt as fuel in many developing countries. Besides pollution from coal combustion, coal briquettes always face problems during transportation and storage because they are friable and susceptible to moisture. On the other hand plastic waste in municipal solid waste is also a big problem which many countries are facing. Since synthetic plastics originate from petroleum products, plastic waste has high energy content. To solve these problems, a new solid fuel called Eco-fuel has been developed by briquetting a mixture of coal and different plastics. The commonly used plastics (polyethylene and polystyrene) were used in this study. Eco-fuel is clean, strong and easy to handle. It is easier to ignite than raw coal. Eco-fuel is resistant to water and water vapour. The acidic emissions of Eco-fuel are lower than that of coal briquette and can be well controlled by adding lime products.

Overall there are several solutions to prevent landslides. The first solution discovered was a drainage system. Another solution found to be effective against landslide prevention is the plantation of deep-rooted crops. The third and final option for a long-term landslide prevention strategy are eco briquettes.