India has been ranked sixth among those countries in the world with the highest landslide-related casualties over the last century. The death toll has been rising due to the increasing frequency of landslides and lack of right landslide monitoring, experts said. Landslides have claimed the lives of hundreds of thousands of people and caused billions of dollars worth of damage all over the world. To minimize loss of life and property, it is crucial to detect, track and record the presence of landslides in essence. Most landslides start with only a very small failure on a slope; however, as the failure spreads out, not only does it increase in the area but also in intensity. Therefore, landslide progress monitoring is an important aspect of mitigating their effects.
Landslides triggered by rain no longer occur only during the rainy season. From Sikkim to Arunachal Pradesh, India is a country full of hills and mountains. The Western Ghats, a 1,500-km-long mountain range bordering the western coast of peninsular India, hosts some of the oldest rainfall-triggered landslides in the world. If it is heavy rain that triggers landslides, they can occur during periods of dry weather too. In such cases, landslides are triggered by water accumulating gradually and then breaking loose. When this happens no one has much time to get to safety before the debris hits their home, and that increases the necessity for landslide monitoring.
In India, particularly in the northern and eastern regions especially in Bengal, Bihar, Uttar Pradesh, and Sikkim, where rainfall is heavy and terrain uneven or hilly, landslides are common during the rainy season. Research has shown that a landslide triggered by heavy rain has the potential of travelling much faster than a regular flow of water. Landslides triggered by rains have been among the deadliest hazards across countries that start experiencing wet seasons. Prevailing monsoon conditions and poor housing occupy a lot of them to be more susceptible to landslides. Hence, such mishaps continue taking scores of lives every year in India. But it looks like landslides triggered by rain no longer occur during just the rainy seasons, according to a recent National Institute of Disaster Management study on India's landslide disasters over the past 100 years. This activity is certainly not restricted to specific months of weak monsoon; it has become a year-round phenomenon, the study said.
While landslides are complex in nature and completely unpredictable, there are ways to reduce the risk. And one of the most used and proven ways is - Landslide monitoring.
Stay Ahead of Any Mishappening With Landslide Monitoring
Landslide monitoring is very important in order to protect material and human loss. A good prediction and forewarning system, when implemented with effective efforts to control and mitigate landslides, can drastically reduce destruction caused by landslides. Unstable slopes require monitoring systems that can be accessed remotely and provide an immediate warning in case of failure. Advances in geotechnical instrumentation, surveying technologies and data transmission systems now make it possible to monitor these slopes conveniently and economically.
The need for landslide monitoring is very common in Kenya and other parts of the world where landslide hazard is a continuous problem during rains. Landslide monitoring is crucial, especially in mountainous areas with a high level of traffic volume and on busy roads. This system aggregates the data from several sensors on a single platform, making it easier for road operators or public agencies to identify potential dangers.
Some landslides are sudden and catastrophic, but others are more gradual. Some might not even be noticeable until the initial movement has occurred if it happens at all. Monitoring conditions to identify any existing unstable land will alert residents before there is a landslide threat.
How Does Landslide Monitoring Work?
The importance of a real-time landslide monitoring system cannot be overemphasized. Remote (near real-time) monitoring of slope movement and other parameters potentially affecting it can be a correct approach for risk mitigation in unstable or potentially unstable slopes. Pore water pressure can be observed using vibrating wire piezometers. Lateral movements and deformations can be determined with in-place inclinometers, tilt meters, extensometers, crack meters and automatic survey systems. The chances of a landslide increase with the increase in rainfalls. Monitoring instrumetation are crucial for collecting data on rainfall and ground movement.
In landslide-prone areas, there are numerous structures that can be affected by a movement. Headworks for water supply systems, footbridges, railroads, public infrastructures, etc. These structures situated close to the unstable slope can cause further damage or even collapse in many cases. Wireless technologies provide more frequent data readings as compared to older technology like optical beacons and cables.
Role of Datalogger in Landslide Monitoring
Dataloggers are invaluable tools in having a real-time monitoring system for landslide detection process, helping scientists gain a better understanding from a remote location and alerting them to possible risks.
All the sensors monitoring different parameters are connected to a datalogger that automatically collects data at selected intervals and trigger an alarm or sends an SMS if pre-determined values are exceeded. Two types of dataloggers are commonly used:
- GSM/GPRS datalogger. A single datalogger can connect several digital sensors, up to 160 sensors. The advantage of the system is that only a single 3 conductor cable is required to interconnect all the sensors and the datalogger in a serial bus. A cellular network is required to transfer the data from the datalogger location to a remote server.
- RF datalogger (node) withg. In this end-to-end wireless monitoring system, the sensors (vibrating wire, analog or digital) are interfaced with the long-range, low-power wireless network through suitable RF dataloggers that send recorded data to the Gateway with utmost reliability. Gateway can be installed at a remote location, but in line of sight of the nodes. It uploads the collected sensor data to the central/cloud server via a cellular network.
Role of Wireless Technology in Landslide Monitoring
Various sensors exist for the detection and warning of approaching movement, including piezometers, in-place inclinometers, tiltmeters, borehole extensometers, crack meters, creep meters, load cells, rain gauges, etc.
These are installed in a landslide prone area, which are often remote locations not connected by cabled power or fiber-optic lines, and are difficult to access. Wireless data transmission helps in having the sensor data remotely, on your laptop/mobile.
Wireless network systems are capable of continuous and unattended operation over long periods, contributing to an integrated early warning system. The wireless system has a great advantage over wired monitoring systems in its ease of installation, flexibility and speed. By eliminating the need for wires, wireless monitoring systems offer more precise readings than wired systems.
Role of Web Based Data Management System in Landslide Monitoring
A highly flexible WEB based or local access data management software is the heart of real-time landslide monitoring system. The database software can combine data from geotechnical sensors as well as geodetic survey targets.
Some of the features of this software are:
- Single platform for comprehensive project data allows rapid evaluation, interpretation and decision-making
- Single portal to manage multiple projects
- Variety of visualization and analysis tools to identify potential failure scenarios.
- Support to have a live visual feed from the project site
- Offers an interactive user interface, taking care of all database interactions automatically
- User defined multiple graphs on single screen provide visual insight for analysis
- Real time multiple alarm setting ensures no critical information is missed.
- All key information can be viewed at a glance on customized screen options
- Virtual variable calculations available for corrections (temperature effect etc.) and re-calibration of sensor
- Instant automatic alerts sent via SMS or email for data variations, missed data or sensor malfunction
- User can generate comprehensive report or a customized report quickly
Let’s talk about the advantages of using wireless monitoring solutions in Landslide monitoring.
Real-time data: Landslide monitoring is about collecting important information about the land site to perform early warning operations in times of landslides. One of the best advantages of using automatic dataloggers, wireless technology and online database management system in landslide monitoring is that it offers real-time data. This allows the stakeholder to check the field data immediately, instead of going through laborious processing procedures or visiting a difficult site location. The use of this technology allows for quick characterization of the location and characteristics of landslides and even tracking their movement.
Gives Enough Time for Safety Preparation: With recent advancements in wireless technology, landslides can be detected and monitored much more quickly than in the past. Benefits for this include giving experts time to come up with an action plan, which could include informing the public of dangers in the area. Also, once a landslide is detected, remedial measures can be planned, such as reinforcing any buildings that might be at risk or evacuating nearby homes.
Accurate Reading: Accurate reading is important in landslide monitoring because it plays a significant role in landslide prediction and reduction. Wireless technologies have recently become popular and provide a alternate approach to rapidly transmitting reliable information from the landslide through conventional means of telemetry. An accurate landslide monitoring system reduces the risk of accidents and enhances safety conditions for the residents near landslide-prone areas.
Better Safety: Safety is not something that should be left to guesswork. Why take more chances than necessary when it comes to land stability? Ensuring that you have a reliable and safe monitoring system is critical when it comes to avoiding potential problems due to a landslide. Wireless monitoring system can deliver all the data you need, at any given time, to determine how safe a certain slope is.
Lower Installation Cost: The overall installation cost of wireless monitoring system is less than a conventional cabled system. Cabled systems require excavation and materials for conduit, cable armoring and protection, connections, and intermediate equipment installations. Wireless systems do not use physical cable, resulting in lesser installation costs.