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How aerial imagery supports flood response

Aug 2023

Aerial mapping and GIS are invaluable tools for flood response. We show you the benefits of these tools for flood mapping, preparation and risk management.

Aug 2023

When flooding occurs, while a lot of factors are out of human control, there are ways we can intervene and mitigate disaster. One of the most vital tools for flood response is aerial mapping. Looking at current and historical imagery of locations from above can provide vital information for infrastructure planning, crisis management, and preventative measures.
Find out how aerial mapping applies to flood hazard mapping, including how you can use aerial imagery and GIS data to create safe, effective flood response plans.

What is flood mapping?

Flood mapping is the process of creating maps or models that show areas at risk of flooding. It involves analysing a range of factors including topography, hydrological data, rainfall patterns and historical flood records to assess the potential extent and severity of flooding in a particular area. The purpose of flood mapping is to identify, visualise and model areas prone to flooding, allowing for better understanding, planning and management of flood risks. Essentially, flood mapping is both a visual aid and a future-proof planning tool for major weather events.
Flood maps typically show different levels of flood risk, often represented by colour-coded zones or contour lines. Such maps are used by governments, emergency management agencies, urban planners and insurance companies to make informed decisions regarding land use, infrastructure development, disaster response and flood insurance. They serve three main purposes — to help in identifying high-risk areas, determining flood protection measures, and guiding evacuation plans during flood events.

How do tools like GIS and aerial maps help with flood mapping?

Tools like Geographic Information Systems (GIS) and aerial maps are instrumental in flood mapping as they offer advanced capabilities for data analysis, visualisation and spatial modelling.
On a holistic level, GIS can integrate various data sources relevant to flood mapping, including aerial imagery, 3D mapping, satellite data, hydrological data and historical flood records. These diverse datasets can be combined and analysed spatially to identify flood-prone areas and assess vulnerability, as well providing an understanding of the underlying factors contributing to flooding.
GIS platforms provide powerful analytical tools for processing, manipulating, and deriving insights from this data, helping planners make the most informed decisions based on a specific location.
On a micro level, GIS lets you create sophisticated flood models using a combination of terrain data, hydrological data, and hydraulic principles. By using elevation data from aerial maps, GIS-based modelling tools can simulate water flow, predict flood extents, and even estimate flood depth in certain scenarios. These models help in assessing the potential impact of floods, evaluating flood mitigation measures and formulating emergency response plans.
We go into more detail about using aerial mapping for flood preparation below.

How to prepare for floods using aerial mapping

Aerial mapping is an essential tool for flood preparation, as it can provide detailed and up-to-date information about the terrain and potential flood risks in an area. Here are some of the main ways aerial mapping can be used in flood preparedness.

Terrain analysis

Aerial mapping can capture high-resolution imagery of the land surface, allowing for detailed analysis of topography, elevation and land features. This information helps identify low-lying areas, natural drainage patterns and potential flood pathways. By understanding the terrain, planning authorities can assess the vulnerability of different regions to flooding and develop appropriate mitigation strategies.

Floodplain mapping

Aerial mapping can be used to delineate floodplains, which are the areas adjacent to rivers or other bodies of water that are prone to flooding. By accurately mapping floodplains, it’s possible to define flood risk zones and establish regulations for land use and development in these areas. This helps in minimising the exposure of infrastructure and communities to flood hazards.

Emergency response planning

Aerial mapping can aid in emergency response planning by providing accurate and up-to-date information on infrastructure, road networks and critical facilities within flood-prone areas. This data helps emergency management agencies identify evacuation routes, plan for the placement of emergency shelters, and coordinate rescue and relief operations effectively when disaster strikes. Nearmap ImpactResponse can provide a detailed view of this information in the wake of major events through near real-time high-resolution imagery and data. This information can be crucial to creating safe, time-sensitive strategies for response, recovery, and repairs.

Flood modelling and simulation

Aerial imagery can be used to create detailed 3D models of an area, which can then be integrated with hydrological data to simulate flood scenarios. These models help predict the potential extent and depth of flooding under different conditions, informing flood forecasting and early warning systems. By incorporating real-time data from weather stations and river gauges, aerial mapping can provide timely information to emergency responders and decision-makers during floods.

Flood risk mitigation during planning

Aerial mapping can assist in infrastructure planning and design by providing accurate spatial data. This includes identifying suitable locations for flood control structures such as levees, dams, and retention ponds. Aerial imagery can also help in assessing the impact of proposed infrastructure projects on flood patterns, which can inform more sustainable drainage system designs to manage excess water during heavy rainfall events.
In addition, flood maps inform the creation of zoning regulations and building codes during the planning process. Planners can establish floodplain zoning, which outlines specific land use regulations and development standards within flood-prone areas. For example, planners may require buildings to be elevated above the base flood level or restrictions to be imposed on certain activities within flood zones. These regulations can help mitigate flood risks and ensure that new developments are designed and constructed for flood resilience.

Finding the best geospatial tools for flood mapping

When it comes to geospatial tools for flood mapping, up-to-date information, quality historical data, and future-focused technology should be at the top of your checklist. Nearmap offers a suite of content, tools, and resources that create a clear and accurate aggregation of location data. The level of detail Nearmap content provides can be the difference between an intelligent, informed flood plan or one that misses crucial vulnerabilities.
Want to know how you can work with better flood hazard mapping? Get in touch today for a quick demo.