Flood History

Environment Agency 2016 Web, Mapping, GIS, Data management

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We were commissioned by the Environment Agency (EA) to develop a masterplan for investment in reducing flood risk. As part of that commission, we developed a website that would be used to record and visualise the history of flooding and flood events in the area.

The site was built using the .NET framework under the Model-View-Controller (MVC) design principle. The data are stored in an SQL Server 2012 spatial database, with much of the user interface and mapping created using open-source products: MapServer for the mapping engine; OpenLayers for mapping interaction and interface; background tile-mapping derived from OpenStreetMap data; and jQuery and Bootstrap Javascript libraries and styling. A Web API is used for sending and receiving data in the site in a flexible, lightweight and transferable way.

The site is hosted in the Cloud using Amazon Web Services (AWS), allowing for flexible increases in power or capacity, scalability, as well as high availability and resilience.

The site features two versions of OpenStreetMap as switchable background layers as well as a further selectable Light Detection and Ranging (LIDAR) background option. The latter is a Digital Terrain Model (DTM) at 2m resolution processed into a greyscale Web Mapping Service (WMS) layer. Other available layers for the user include various EA flood risk datasets including the Risk of Flooding from Surface Water and the Flood Map for Planning. These flood layers are ingested as WMS layers from the EA. Further data layers can be readily added, demonstrating the flexibility and customisation of the system.

Finally, the main purpose of the site is to feature flood events as points and polygons. Users can see any events that have already been added and approved on the site; they can also add their own events by drawing on the map and adding further details. Further, they can upload data in spreadsheet or shapefile format in order to bring in multiple event data. Any suggested event data must be approved by an administrator before they become public.

For any event that is on the site, users may also add relevant media, including photographs, PDFs and Microsoft Word files, and videos. Media are stored in AWS Simple Storage Service (S3) in order not to affect the performance and disk space of the web server itself. The file types accessible can be managed to restrict certain media types if required.

The interface includes a date ‘slider’, which lets the user easily filter the flood data in the view according to the recorded date of events.

For information on this project, contact Roger Winterbottom on 01756 699500.