Streamlining Disaster Recovery with ICT! Using Drones to Cut Restoration Time by 50%

Challenges and Needs in Disaster Recovery

In recent years, Japan has experienced frequent natural disasters such as earthquakes, typhoons, and heavy localized rainfall. When roads are severed, river embankments breach, or landslides occur, rapid infrastructure restoration is directly linked to community safety and security. However, traditional civil engineering recovery efforts often require substantial manpower and time, and it is not uncommon for resolving isolation of affected areas and restoring lifelines to take prolonged periods. The larger the scale of damage, the longer restoration work can take, impacting local economies and residents’ lives during that time. From this perspective, there is a strong demand for streamlining recovery works, i.e., significantly shortening work durations and reducing labor.

Furthermore, the construction and civil engineering sectors face a severe shortage of workers, meaning that in the event of a large-scale disaster, a limited workforce must respond to numerous recovery sites. At the forefront of attention are the use of drones and ICT (information and communication technology). By leveraging the latest technologies to streamline processes from surveying and design to construction management, it is becoming possible to shorten the overall recovery period to less than half of traditional timelines. This article explains concrete methods by which introducing ICT and drones into disaster recovery sites can accelerate and improve accuracy across each process, reducing restoration time by more than 50%.

Limits of Conventional Methods and Causes of Delays

When a major disaster occurs, the sequence typically starts with assessing site conditions and damage surveys, followed by considering and designing recovery methods, then ordering and executing the work. However, conventional methods have various bottlenecks at each stage, often delaying the start of recovery. Major causes of delays include:

• Surveys and measurements are time-consuming: Traditionally, technicians went to the site and used total stations and staffs to measure dimensions and terrain point by point. Broad-area surveys can take days to weeks, during which full-scale recovery design cannot begin.

• Work constraints in hazardous areas: Disaster sites often have unstable ground and the risk of secondary disasters. Information about steep slopes or swollen rivers—areas where people cannot approach—is hard to obtain with conventional methods, and work may have to be suspended or postponed to ensure safety.

• Delays in information sharing and decision-making: If site damage information and survey data are managed as paper drawings or photographs, sharing them among stakeholders takes time. Sending data to responsible departments or partner companies and explaining them in meetings consumes effort, delaying decisions on recovery policy and the start of design.

• Person-dependent tasks and labor shortages: Traditional surveying and design rely heavily on the experience and intuition of skilled personnel, concentrating the burden on a limited number of technicians. When many locations are damaged in a single disaster, there may be insufficient manpower to quickly cover all sites.

Due to these factors, conventional disaster recovery often took a long time from immediately after the disaster until project completion. As a solution to these issues, reforming business processes through drone and ICT utilization is attracting expectations.

Speed and Accuracy of Situation Assessment with Drones

Aerial photography and photogrammetry using drones (unmanned aerial vehicles) are extremely effective for understanding the situation at disaster sites. Flying a drone overhead enables rapid imaging of the entire damage area, including dangerous places where people cannot enter. By capturing continuous aerial photos with high-resolution cameras mounted on drones and processing them with specialized software, detailed orthophotos (overhead real images) and three-dimensional models of the site can be produced. Surveys that previously took technicians days of manual work can be completed in only a few hours to about a day when combining drone flights and image analysis. For example, one road restoration site reported that terrain surveys that previously required four days in total were completed in half a day after introducing drones. In another riverworks case, initial surveys that used to take over a week were shortened to about two days with drones. Using drones in this way drastically reduces the time needed for situation assessment and enables earlier development of recovery plans.

The advantages of drone surveying are not limited to speed. Data captured from above are extremely high-density and high-precision, providing detailed topographic information that human survey teams cannot obtain. Point cloud data consisting of tens of millions of points can accurately capture subtle terrain undulations and tilting of damaged structures. This allows detection of small-scale collapses and cracks that might have been overlooked previously, leading to more appropriate choices of recovery methods. Drones also record damage without exposing workers to risk, offering safety advantages. In fact, during Typhoon Hagibis (Typhoon No. 19) in 2019, drone footage of a breached embankment was quickly shared and served as a basis for planning recovery work. Initial surveys that once relied on helicopters or manual methods can now be conducted quickly and in detail thanks to drone mobility.

Displacement Analysis and Volume Estimation Using Point Cloud Data

Three-dimensional point cloud data obtained with drones or laser scanners are powerful for quantitatively analyzing terrain changes and structural displacements caused by disasters. A point cloud is digital data representing the surface of terrain or objects with countless measurement points; by comparing pre- and post-disaster topography, one can determine where and how much movement has occurred. For example, in a large landslide, overlaying pre-collapse terrain data with post-collapse point cloud models enables accurate calculation of the volume of collapsed material. Traditionally, on-site longitudinal and cross-sectional surveys were used to roughly estimate volumes, which required time, but digital point cloud comparisons deliver reliable figures quickly.

Displacement analysis follows the same principle. On a slope affected by a landslide, point cloud data can reveal how many meters the ground surface moved compared to pre-disaster conditions and which areas have subsided or heaved. Specialized analysis software can display the elevation differences between two point cloud models as a color-coded heat map, making deformation amounts immediately visible. This enables rapid prioritization of areas with large changes or high risk. Calculated soil volumes directly inform arrangements for trucks and heavy equipment, and planning for waste disposal, making them vital for optimizing project schedule and cost. By leveraging point cloud data, terrain changes due to disasters can be understood quantitatively and intuitively, allowing formulation of recovery policies at unprecedented speed.

Immediate Use of Photogrammetry for Design and Procurement

Orthophotos and point cloud data obtained through drone photogrammetry can be immediately applied in the design phase of recovery works. Traditionally, survey maps and cross-sections of damaged sites were produced first, and designers used those to consider construction methods, but photogrammetric outputs can greatly reduce that workload. Specifically, it is possible to directly evaluate layout and dimensional planning of recovery structures on the 3D model captured by the drone.

For example, when constructing a retaining wall on a collapsed slope, designers can extract arbitrary cross-sections from point cloud data to compare pre- and post-damage terrain and instantly determine required wall height and foundation position. Designers can review recovery proposals on a PC in the office while viewing the 3D model and even perform quantity calculations (soil volume and material requirements) on the spot. What used to be a process of field survey → drafting → design planning → quantity calculation taking several days can, using photogrammetric data, be nearly completed in a one-stop workflow.

Moreover, these digital data are useful at the procurement stage. Municipalities and managers issuing contracts can provide 3D models and orthophotos directly as explanatory materials to contractors, allowing bidders to accurately grasp site conditions when preparing estimates and construction plans. In some cases, bidders can obtain the necessary information from drone data and submit bids without visiting the site, which is a significant advantage under time-limited emergency work. For contractors, early sharing of detailed as-built data and design conditions enables efficient preparation before mobilization. By linking photogrammetric outputs directly to design and procurement processes, unnecessary time lags are removed and the overall period of disaster recovery projects can be shortened.

Progress and Stakeholder Sharing via the Cloud

In ICT-driven disaster recovery, data sharing via the cloud is key to smooth information transmission and efficient progress management. Previously, survey data and photos were taken back on USB drives and stored on internal servers, and paper drawings were distributed to stakeholders. With the cloud, data can be uploaded directly from the site and shared instantly. For example, if 3D models and orthophotos generated from drone imagery are saved in a cloud project folder, designers and clients in distant offices can view and review the data the same day. When design revisions are needed, the latest data can be exchanged in real time between the field and the office, enabling rapid on-site adjustments.

Also effective is visualizing progress on cloud services and sharing it among all stakeholders. By centralizing project schedules, completion status of each process, daily site photos, and drone imagery on a dashboard, clients, contractors, and designers can discuss using the same up-to-date information. This reduces misunderstandings when problems arise and accelerates decision-making. Disaster recovery often involves multiple agencies (national, prefectural, municipal governments, and lifeline operators), so centralized cloud-based data and reporting help prevent coordination errors and enable smooth role allocation.

Furthermore, cloud usage contributes to more efficient data processing. Computationally intensive tasks like analyzing large point clouds or generating 3D models from photographs can be executed on high-performance cloud servers to produce results quickly. This allows access to the latest technologies regardless of the on-site PC environment. Disaster record data stored in the cloud also serve future disaster prevention planning and maintenance. For instance, past point cloud datasets can be referenced to analyze terrain changes over time or compared with cases from other regions. Overall, open information sharing through the cloud is indispensable for improving efficiency in recovery works and facilitating smooth collaboration among stakeholders.

Cases from Municipalities and Contractors (Concrete Examples)

There are increasing cases across regions where drones and ICT have been used to streamline disaster recovery. Among municipal initiatives, drone use in initial response immediately after damage is notable. One local government completed assessment of the damage range at a large landslide site—previously requiring several days of manual surveying—within the same day using drone aerial photography, enabling rapid development of recovery plans. In another prefecture, detailed orthophotos of a forest road collapsed by heavy rain were recorded by drone, allowing early procurement of emergency repair work. As municipalities take the lead in introducing ICT, local construction companies are also adopting digital technologies, and a new standard—"confirming the site by drone first in disasters"—is emerging.

As for contractors, some small-to-medium civil engineering firms have established in-house ICT teams and started training in drone operation and 3D data processing. A construction company in Tokyo quickly responded to the Ministry of Land, Infrastructure, Transport and Tourism's i-Construction initiative, introducing in-house drone surveying and ICT-equipped machinery. As a result, surveying tasks were reduced by nearly 80% compared to traditional methods, and safety dramatically improved by keeping personnel out of hazardous slopes. Using 3D models of collapsed areas, the company swiftly developed earthwork plans and implemented batter-board-free construction with ICT-equipped machines, achieving schedule reductions and labor savings. Such initiatives also enhance corporate competitiveness, and these firms have been highly rated by clients as contractors who "complete work quickly and safely."

Simple Site Surveying with LRTK (Control Point Measurement, As-Built Verification, Location Recording)

In addition to streamlining upstream processes with drones and the cloud, new technologies for simple surveying are proving powerful at actual construction sites. A representative example is RTK surveying technology using smartphones combined with GNSS (Global Navigation Satellite System), commonly called "LRTK." RTK (Real Time Kinematic) enhances positioning accuracy by applying differential corrections to satellite positioning information, achieving centimeter-level precision. Where once high-precision GNSS equipment costing millions of yen was required, recent advances allow using a smartphone with a compact RTK receiver attachment or smartphones with high-performance GNSS chips, turning a smartphone into a high-precision surveying tool.

Using LRTK dramatically improves efficiency for on-site control point surveys, as-built (finished shape) verification, and recording of position information. For example, installing construction control points that previously required two people and half a day can be done quickly by one person with just a smartphone and correction data. Obtained control point coordinates can be shared immediately via the cloud, eliminating time losses from suspending work to wait for survey results. Smartphone-based RTK surveying is also intuitive and easy to operate, allowing site staff without special qualifications to perform measurements with a certain level of accuracy. This enables onsite teams to conduct the minimum necessary surveying independently even when it is difficult to arrange a surveyor during emergencies.

LRTK is also useful for as-built verification. For embankments and slope shaping, heights at specific points can be measured with a smartphone to confirm compliance with design on the spot. Where needed, measured points can be compared against design data on the smartphone to check for discrepancies. Tasks that used to be verified after construction using batter-board-based measurements can now be done in real time, enabling early rework or adjustments to material quantities. Smartphones also include cameras, allowing measurement point photos to be saved with location information—useful for recording discovery locations of buried utilities or logging cracks that require ongoing observation. Introducing simple surveying with LRTK enables nimble measurements and instant information sharing on site, significantly enhancing responsiveness in recovery work.

Implementation Steps and Cost Estimates

Introducing drone and ICT utilization as described above requires phased planning and investment, but with appropriate implementation can yield significant benefits. Typical implementation steps and approximate cost ranges are as follows:

• Clarify needs and develop a plan: First, identify which parts of your organization’s workflows you want to digitize and streamline. Organize needs such as damage recording, sharing design data, and construction management, and develop an ICT adoption plan.

• Select technologies and prepare equipment: Decide on ICT technologies and equipment to be used. Specifically, this may include drones (camera-equipped platforms or LiDAR-equipped units as needed), photogrammetry software (or cloud services), 3D design CAD or CIM tools, cloud-sharing platforms, and LRTK devices (smartphone GNSS receivers). Also prepare in advance to comply with regulations such as drone flight permissions and radio-use applications.

• Human resource development and organizational setup: Train operators who handle equipment and personnel who process data. Since drone operation has become a nationally certified qualification, secure qualified personnel internally or collaborate with external professionals. Establish dedicated teams or staff to promote ICT adoption and act as liaisons between the field and headquarters/design departments.

• Pilot implementation (pilot project): Rather than deploying immediately on live disaster sites, test operations on small sites or with historical data. Test the workflow from drone capture to data processing and cloud sharing to identify issues and operational challenges. Conduct internal training and demonstrations to deepen on-site staff understanding of new technologies.

• Full deployment and standardization: Based on insights from pilots, integrate ICT into actual disaster recovery operations. Standardize operational rules both internally and externally—for example, using drone initial surveys or requiring submission of 3D data in tender documents. Validate effects (time reduction, improved safety, etc.) through real projects and refine operational flows based on feedback.

Regarding costs, prices vary depending on equipment and services adopted. As a reference, industrial drone packages including aircraft, camera, batteries, and peripherals typically range from several hundred thousand to several million yen. Photogrammetry software bought outright can start at several hundred thousand yen, and cloud services may be available from tens of thousands of yen per month. Smartphone-connected GNSS receivers for LRTK are on the market for around one hundred thousand yen, making them a lower-cost alternative to expensive dedicated equipment. Although initial investment is required, the reduction in labor costs from shorter schedules and the mitigation of social losses through earlier recovery often make the investment worthwhile. Additionally, government and municipal incentives or subsidy programs aimed at promoting ICT adoption may be available, so leveraging such support while proceeding in stages is recommended.

Future Prospects (AI Integration, Remote Support, Integrated Dashboards)

Disaster recovery support through ICT and digital technologies is evolving rapidly, and further advanced applications are expected. Finally, here are some prospects to watch.

• Automated damage assessment with AI: Going forward, AI is expected to analyze images and point cloud data from drones to automatically recognize damaged areas and assess risk levels. Research is already underway that uses multi-temporal point cloud data for AI to detect slope movements or classify building damage levels via image recognition. If AI can instantaneously draft damage reports or create priority maps for recovery, initial response speed would increase dramatically.

• Remote support and unmanned construction: The use of virtual sites created from drone data and live imagery will expand remote expert support and guidance. For example, technicians at headquarters may use VR goggles to view 3D imagery of a disaster site and give precise advice to field staff. As communication infrastructure and robotics advance, remote operation of heavy machinery and automated construction at disaster sites may also become commonplace. If remote-operated equipment can clear debris or perform emergency repairs without people entering dangerous collapse zones, safety and speed of operations will further improve.

• Integrated dashboards and disaster prevention platforms: The adoption of integrated dashboards that consolidate multiple information sources is also expected to progress. Disaster response involves diverse data—terrain data from drones, on-site work progress, resource and personnel allocation, as well as weather and evacuation information. In the future, these will likely be integrated into a disaster information platform where relevant organizations can share data and make decisions in real time. Overlaying a 3D map of affected areas with a construction dashboard on a single screen would allow everyone to share the same situational awareness and coordinate recovery work more effectively, enabling even faster and more efficient responses than before.

In this way, the efficiency and sophistication of civil engineering work through ICT are steadily advancing in the field of disaster recovery. With technological progress, it is becoming possible to restore infrastructure with speeds and accuracy previously unattainable by humans alone. Actively adopting advanced technologies such as drones and AI will become the standard in future civil engineering and disaster prevention, helping to realize faster recovery and reconstruction for affected communities.